Cara Therapeutics Inc

1. Business

Cara Therapeutics, Inc., or the Company, is a development-stage biopharmaceutical corporation formed on July 2, 2004. The Company is leading a new treatment paradigm to improve the lives of patients suffering from pruritus. The Company’s primary activities to date have been organizing and staffing the Company, developing its lead product and product candidates, including conducting preclinical studies and clinical trials of difelikefalin-based product candidates, and raising capital.

In August 2021, the Company received U.S. Food and Drug Administration, or FDA, approval for KORSUVA® (difelikefalin) injection, or KORSUVA injection, for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. Commercial launch of KORSUVA injection began in the United States in April 2022 and the Company began recording the associated profit-sharing revenues in the second quarter of 2022.

In April 2022, the European Commission granted marketing authorization to difelikefalin injection under the brand name Kapruvia® (difelikefalin), or Kapruvia, for the treatment of moderate-to-severe pruritus associated with chronic kidney disease in adult hemodialysis patients. The marketing authorization approved Kapruvia for use in all member states of the European Union, or EU, as well as Iceland, Liechtenstein, and Norway. Kapruvia was also approved in the United Kingdom in April 2022. Commercial launches in Austria, Germany, Sweden, France, the Netherlands, and Finland have commenced. In August 2022, as part of the Access Consortium, difelikefalin injection was approved in Switzerland under the brand name Kapruvia, as well as Singapore and Canada under the brand name KORSUVA. In November 2022, difelikefalin injection was approved in the last Access Consortium country, Australia, under the brand name KORSUVA. Difelikefalin injection was also approved in the United Arab Emirates, Kuwait, Israel, and Japan under the brand name KORSUVA in January 2023, May 2023, June 2023, and September 2023, respectively. The Company expects additional approvals and commercial launches over the next 12-18 months. On November 1, 2023, the Company entered into a Purchase and Sale Agreement, or the HCR Agreement, with HCRX Investments Holdco, L.P. and Healthcare Royalty Partners IV, L.P., or collectively HCR, where HCR will receive future royalty and milestone payments for Kapruvia and KORSUVA (ex U.S. only) up to certain capped amounts in exchange for certain payments to the Company (see Note 10,Royalty Purchase and Sale Agreement).

In 2018, the Company entered into a licensing and collaboration agreement with a joint venture between Vifor Pharma Group and Fresenius Medical Care Renal Pharmaceutical Ltd., or Vifor Fresenius Medical Care Renal Pharma Ltd., that provides full commercialization rights of Kapruvia, and where applicable KORSUVA, to Vifor Fresenius Medical Care Renal Pharma Ltd. worldwide (excluding the United States, Japan, and South Korea). In 2020, the Company entered into a second licensing and collaboration agreement, along with stock purchase agreements, with Vifor (International) Ltd., or Vifor International, that provides full commercialization rights of KORSUVA injection to Vifor International in dialysis clinics in the United States under a profit-sharing arrangement (see Note 13,* Collaboration and Licensing Agreements*).

In May 2022, Vifor International assigned its rights and obligations under the license agreement and a supply agreement, as permitted under the agreements, to Vifor Fresenius Medical Care Renal Pharma Ltd. The Company’s rights and obligations under these agreements were unaffected by this assignment, and the assignment did not affect the Company’s economic rights under the agreements with Vifor International.

In August 2022, Vifor Pharma Group (which includes Vifor International) was acquired by CSL Limited and subsequently renamed CSL Vifor as part of the acquisition. The acquisition of Vifor Pharma Group did not affect any of the Company’s rights and obligations pursuant to these agreements.

The Company also has a license agreement with Maruishi Pharmaceutical Co. Ltd., or Maruishi, under which the Company granted Maruishi an exclusive license to develop, manufacture, and commercialize drug products containing difelikefalin for acute pain and/or uremic pruritus in Japan. In September 2023, Maruishi received manufacturing and marketing approval from Japan’s Ministry of Health, Labour and Welfare for KORSUVA IV Injection Syringe for the treatment of pruritus in hemodialysis patients. In conjunction with the approval, the Company earned a $1,449 milestone payment per the terms of the licensing agreement (see Note 13,Collaboration and Licensing Agreementsand Note 14*, Revenue Recognition)*. On November 1, 2023, the Company entered into the HCR Agreement where HCR will receive future royalty and milestone payments for KORSUVA (Japan) up to certain capped amounts in exchange for certain payments to the Company (see Note 10,Royalty Purchase and Sale Agreement).

As of December 31, 2023, the Company has raised aggregate net proceeds of approximately $520,700 from several rounds of equity financing, including its initial public offering, or IPO, which closed in February 2014 andfour follow-on public offerings of common stock, which closed in July 2019, July 2018, April 2017 and August 2015, respectively, the issuance of common stock pursuant to its open market sales agreement with Jefferies LLC as sales agent, or the Sales Agreement, in 2023 and the issuance of convertible preferred stock and debt prior to the IPO. Including profit share revenue and royalties, the Company has also earned approximately $287,000 under its license and supply agreements for difelikefalin, primarily with CSL Vifor, Maruishi, and Chong Kun Dang Pharmaceutical Corp., or CKDP, and an earlier product candidate for which development efforts ceased in 2007. Under the terms of the HCR Agreement, the Company received net proceeds of $36,474 for the sale of future ex U.S. royalties and milestones under Vifor Agreement No. 2 and the Maruishi Agreement in November and December 2023. In October 2021, the Company received net proceeds of $44,969 from the issuance and sale of 3,282,391 shares of the Company’s common stock to Vifor International in connection with U.S. regulatory approval for KORSUVA injection in August 2021. Additionally, in October 2020, the Company received net proceeds of $38,449 from the issuance and sale of 2,939,552 shares of the Company’s common stock to Vifor International in connection with the Company’s license agreement with Vifor International. Furthermore, in May 2018, the Company received net proceeds of $14,556 from the issuance and sale of 1,174,827 shares of the Company’s common stock to Vifor International in connection with the Company’s license agreement with CSL Vifor (see Notes 11,Stockholders’ Equity and 13,Collaboration and Licensing Agreements).

As of December 31, 2023, the Company had unrestricted cash and cash equivalents and marketable securities of $100,758 and an accumulated deficit of $684,745. The Company has incurred substantial net losses and negative cash flows from operating activities in nearly every fiscal period since inception and expects this trend to continue for the foreseeable future. The Company recognized net losses of $118,513, $85,474, and $88,441 for the years ended December 31, 2023, 2022 and 2021, respectively. The Company had net cash used in operating activities of $92,078, $78,730, and $60,087 for the years ended December 31, 2023, 2022 and 2021, respectively.

The Company is subject to risks common to other life science companies including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing, and compliance with FDA and other government regulations. If the Company does not successfully develop and commercialize its other product candidate, it will be unable to generate additional recurring product revenue or achieve profitability.

2. Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The Company’s consolidated financial statements include the results of the financial operations of Cara Therapeutics, Inc. and its wholly-owned subsidiary, Cara Royalty Sub, LLC, or Cara Royalty Sub, a Delaware limited liability company which was formed in November 2023 for the purpose of the transactions contemplated by the HCR

Agreement described in Note 10,Royalty Purchase and Sale Agreement. All intercompany balances and transactions have been eliminated.

The Company’s consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States, or GAAP.

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities, as of the date of the consolidated financial statements as well as the reported amounts of revenues and expenses during the reporting period. The more significant estimates include the fair value of marketable securities that are classified as level 2 of the fair value hierarchy, the amount and periods over which certain revenues will be recognized, including licensing and collaborative revenue recognized from non-refundable up-front and milestone payments and future ex U.S. royalties and milestones projected in relation to the HCR Agreement, related party accounts receivable reserve, as applicable, inventory valuation and related reserves, research and development, or R&D, clinical costs and accrued research projects included in prepaid expenses and accounts payable and accrued expenses, the amount of non-cash compensation costs related to share-based payments to employees and non-employees, the incremental borrowing rate used in lease calculations and the likelihood of realization of deferred tax assets.

The impact from global economic conditions and potential and continuing disruptions to and volatility in the credit and equity markets in the United States and worldwide are highly uncertain and cannot be predicted, including impacts from public pandemics or future global health crises, geopolitical tensions, such as the ongoing conflicts between Russia and Ukraine, conflicts in the Middle East, and increasing tensions between China and Taiwan, and government actions implemented as a result of either of the foregoing, high rates of inflation, rising interest rates, uncertainty and liquidity concerns in the broader financial services industry, such as those caused by certain recent banking failures, and a potential recession in the United States. Estimates and assumptions about future events and their effects cannot be determined with certainty and therefore require the exercise of judgment. As of the date of issuance of these consolidated financial statements, the Company is not aware of any specific event or circumstance that would require the Company to update its estimates, assumptions and judgments or revise the reported amounts of assets and liabilities or the disclosure of contingent assets and liabilities. These estimates, however, may change as new events occur and additional information is obtained, and are recognized in the consolidated financial statements as soon as they become known.

Actual results could differ materially from the Company’s estimates and assumptions.

Concentration of Credit Risk

The Company’s financial instruments, which potentially subject the Company to significant concentrations of credit risk consist primarily of cash and cash equivalents, marketable securities, and related party accounts receivable. The Company invests its cash reserves in money market funds or high-quality marketable securities in accordance with its investment policy. The stated objectives of its investment policy are to preserve capital, provide liquidity consistent with forecasted cash flow requirements, maintain appropriate diversification and generate returns relative to these investment objectives and prevailing market conditions. The Company’s investment policy includes guidelines on acceptable investment securities, limits interest-bearing security investments to certain types of debt and money market instruments issued by the U.S. government and institutions with investment grade credit ratings and places restrictions on maturities and concentration by asset class and issuer. The Company’s cash and cash equivalents and marketable securities are held bythree major financial institutions. In accordance with the Company’s policies, the Company monitors exposure with its counterparties. The Company also maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and

management believes that the Company is not exposed to significant credit risk due to the financial position of the depository institutions in which those deposits are held.

The percentages of revenue recognized from license agreement partners of the Company in the years ended December 31, 2023, 2022 and 2021 are included in the following table:

• Includes amounts earned from Vifor Fresenius Medical Care Renal Pharma Ltd. and Vifor International prior to Vifor International’s assignment of its rights and obligations to Vifor Fresenius Medical Care Renal Pharma Ltd. in May 2022.

For the years ended December 31, 2023, 2022 and 2021, no additional license agreement partners or customers accounted for more than 10% of the Company’s revenue.

Concentration of Suppliers

The Company relies onthree suppliers to manufacture KORSUVA injection active pharmaceutical ingredient, or API, finished drug product, and finished goods. If any of the Company’s suppliers were to limit or terminate production or otherwise fail to meet the quality or delivery requirements to satisfy the supply commitments, the process of locating and qualifying alternate sources would require up totwo years, during which time production could be delayed. Such delays could have a material adverse effect on the Company’s business, financial position, and results of operations.

Cash and Cash Equivalents

Cash and cash equivalents include cash on hand, demand deposits, deposits with banks and highly liquid money market funds with holdings of cash and other investments with original maturities of three months or less.

Marketable Securities

The Company deems certain of its investments to be marketable securities if the investment, or in the case of money market funds, the securities underlying the money market fund, meet the definition of a debt security. The Company’s investments in marketable securities, historically including U.S. Treasury securities, U.S. government agency obligations, corporate bonds, commercial paper, and municipal bonds are highly rated by Moody’s and S&P and have maturities of less than one year as of December 31, 2023. Accordingly, credit risk associated with the Company’s available-for-sale debt security portfolio is mitigated.

The Company reviews each of its available-for-sale marketable securities for unrealized losses (declines in fair value below its amortized cost basis) at each balance sheet date presented in its consolidated financial statements and whenever events or changes in circumstances indicate that the amortized cost basis of an asset may not be recoverable. The Company determines whether any portion of the unrealized loss for any available-for-sale debt security is due to a credit loss, and if so, measures the amount of the credit loss.

The Company relies on both qualitative and quantitative factors to determine whether the unrealized loss for each available-for-sale debt security at any balance sheet date is due to a credit loss.

Qualitative factors may include a credit downgrade, severity of the decline in fair value below amortized cost and other adverse conditions related specifically to the security, as well as the intent to sell the security, or whether the Company will “more likely than not” be required to sell the security before recovery of its amortized cost basis. The Company’s assessment of whether a security is impaired could change in the future due to new developments or changes in assumptions related to any particular security. If material qualitative factors indicate that a credit loss has occurred, the Company will determine the magnitude of that credit loss using a discounted cash flow model or other quantitative method.

If the Company intends to sell the security or it is “more likely than not” that the Company will be forced to sell the security before recovery of the amortized cost of the security, the entire unrealized loss is deemed to be a credit loss, which is recognized in net loss. Otherwise, the portion of the unrealized loss that is due to a credit loss will be recorded as an allowance for credit loss, which will offset the balance of marketable securities and as credit loss expense within other income, net. The portion of the unrealized loss that is not due to a credit loss as well as all unrealized gains will be recorded in Accumulated Other Comprehensive (Loss) Income (see Note 3,Available-for-Sale Marketable Securities, and Note 12,Fair Value Measurements).

Accrued interest receivables are excluded from the Company’s amortized cost bases for its available-for-sale marketable securities and are included within other receivables. The Company’s policy is to not measure an allowance for credit losses on accrued interest receivable balances at each reporting period since it elects to write off uncollectible accrued interest receivable balances as credit loss expense in a timely manner, which is by maturity date for all categories of its debt securities.

Fair Value of Financial Instruments

The Company applies fair value accounting for all financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. The Company defines fair value as the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities which are required to be recorded at fair value, the Company considers the principal or most advantageous market in which it would transact and the market-based risk measurements or assumptions that market participants would use in pricing the asset or liability, such as risks inherent in valuation techniques, transfer restrictions and credit risks.

The Company’s financial instruments consist of cash, cash equivalents, available-for-sale marketable securities, accounts receivable, net – related party, prepaid expenses, restricted cash, accounts payable and accrued liabilities, and liability related to the sales of future royalties and milestones. The fair values of cash, cash equivalents, accounts receivable, net – related party, prepaid expenses, restricted cash, accounts payable and accrued liabilities approximate their carrying values due to the short-term nature of these financial instruments. The fair value of the liability related to the sales of future royalties and milestones approximates the carrying value due to the short period of time that has elapsed from the origination date. Available-for-sale marketable securities are reported at their fair values, based upon pricing of securities with the same or similar investment characteristics as provided by third-party pricing services, as described below.

The valuation techniques used by the Company are based on observable and unobservable inputs. Observable inputs reflect readily obtainable data from independent sources, while unobservable inputs reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances.

The Company classifies its investments in a fair value hierarchy that is intended to increase consistency and comparability in fair value measurements and related disclosures. The fair value hierarchy is divided into three levels based on the source of inputs as follows:

The Company records transfers between levels in the hierarchy by assuming that the transfer occurred at the end of the quarter or year-to-date period.

Valuation Techniques - Level 2 Inputs

The Company estimates the fair values of its financial instruments categorized as level 2 in the fair value hierarchy, historically including U.S. Treasury securities, U.S. government agency obligations, corporate bonds, commercial paper and municipal bonds, by taking into consideration valuations obtained from third-party pricing services. The pricing services use industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities, benchmark yields, issuer credit spreads, benchmark securities, and other observable inputs. The Company obtains a single price for each financial instrument and does not adjust the prices obtained from the pricing service.

The Company validates the prices provided by its third-party pricing services by reviewing their pricing methods, obtaining market values from other pricing sources and comparing them to the share prices presented by the third-party pricing services. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by its pricing services as of December 31, 2023 or December 31, 2022.

Accounts Receivable, Net – Related Party

Accounts receivable, net – related party primarily consists of amounts due from sales of KORSUVA injection under the Company’s supply agreements with CSL Vifor, as well as revenues earned from its share of the profit generated from KORSUVA injection sales in the United States under the licensing agreements with CSL Vifor and royalty payments to the Company under Vifor Agreement No. 2. The Company does not obtain collateral for its accounts receivable.

The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for credit losses when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices and the overall quality and age of those invoices not specifically reviewed. The Company believes that credit risk associated with its licensing partners, CSL Vifor and Maruishi, is not significant. The Company reviews the need for an allowance for credit losses for any receivable based on various factors including payment history and historical bad debt experience. The Company had an insignificant allowance for credit losses as of December 31, 2023.

Inventory, net

Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of inventory using first-in, first-out, or FIFO, method.

The Company capitalizes inventory costs associated with the Company’s products prior to regulatory approval, when, based on management’s judgment, future commercialization is considered probable and the future economic benefit is expected to be realized; otherwise, such costs are expensed. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval. As KORSUVA injection is the Company’s first commercial product and probability could not be established prior to regulatory approval on August 23, 2021, all inventory costs prior to regulatory approval were expensed as incurred.

The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale or has a cost basis in excess of its estimated realizable value and writes down such inventories as appropriate. In addition, the Company’s products are subject to strict quality control and monitoring which the Company performs throughout the manufacturing process. If certain batches or units of product no longer meet quality specifications or become obsolete due to expiration, the Company records a charge to write down such unmarketable inventory to its estimated realizable value.

Property and Equipment, net

Property and equipment (consisting of computer and office equipment, furniture and fixtures and leasehold improvements) are stated at cost, net of accumulated depreciation and amortization of leasehold improvements. Depreciation and amortization are calculated using the straight-line method over the estimated useful lives of the respective assets. Leasehold improvements are amortized over the lesser of their useful lives or the life of the lease. Leasehold improvements also include leasehold improvements in process which relate to leasehold improvements not yet completed for our new principal office. Amortization of leasehold improvements in process begins when the improvements are completed and transferred to leasehold improvements.

The Company reviews the recorded values of property and equipment for impairment whenever events or changes in business circumstances indicate that the carrying amount of an asset or group of assets may not be fully recoverable.

Leases

The Company hasone lease, a new lease agreement in May 2023 for new principal office space in Stamford, Connecticut, or the New Lease, which is included in operating lease-right of use assets, or ROU assets, operating lease liabilities – current and operating lease liabilities – non-current as of December 31, 2023. The Company hadtwo leases, a lease agreement for previous office space, or the Stamford Lease, and an amendment to the Stamford Lease to add additional office space, or the Lease Amendment, which was included in ROU assets and operating lease liabilities –

current as of December 31, 2022. Both the Stamford Lease and Lease Amendment were not renewed and, as a result, terminated in December 2023 (see Note 19,Commitments and Contingencies: Leases).

In general, the Company determines if a contract, at its inception, is a lease or contains a lease based on whether the contract conveys the right to control the use of identified property, plant, or equipment (an identified asset) for a period of time in exchange for consideration. To determine whether a contract conveys the right to control the use of an identified asset for a period of time, the Company assesses whether, throughout the period of use, it has both the right to obtain substantially all of the economic benefits from use of the identified asset, and the right to direct the use of the identified asset. Both of these criteria were met by the Stamford Lease, the Lease Amendment, and the New Lease.

The Company accounted for the terms and conditions of the Lease Amendment as a lease modification because it granted an additional right-of-use to an underlying asset (the new additional space). A lease modification can result in either a new lease that is accounted for separately from the original lease or as a single modified lease. The Lease Amendment was accounted for separately from the original Stamford Lease because the Lease Amendment granted the right-of-use to additional space and the price of the additional right-of-use was commensurate with its standalone price as no discounts were provided to the Company. Furthermore, there were no material changes to the original Stamford Lease.

The Stamford Lease, the Lease Amendment and the New Lease contained both a lease and non-lease component which were accounted for separately. The Company allocated the consideration to the lease and the non-lease component on a relative standalone price basis.

Since the Stamford Lease and Lease Amendment did not provide an implicit interest rate, the Company used an annual incremental borrowing rate of 7% for each, which is based on the rate that the Company could obtain in the market for a fully collateralized loan equal to the term of the Stamford Lease and the Lease Amendment. Similarly, since the New Lease also did not provide an implicit interest rate, the Company used an incremental borrowing rate equal to the 3-month Secured Overnight Financing Rate, or SOFR, plus 7.75% per annum subject to a 3-month SOFR floor of 2.75%, which was based on the rate that the Company could obtain in the market for a fully collateralized loan equal to the term of the New Lease, or 12.83%.

The Company determines the amount of the operating lease liability for its leases based on the present value of the future minimum lease payments over the term of the lease. The amount of the operating lease ROU asset is equal to the amount of the lease liability, less accrued rent and lease incentives received from the landlord. There were no lease incentives identified in the Stamford Lease and the Lease Amendment, but lease incentives were identified in the New Lease which reduced the initial ROU asset for the New Lease. Initial direct costs were deemed to be immaterial for all of the Company’s leases. During the term of the lease, interest expense is calculated using the effective interest method and the ROU asset is amortized on a straight-line basis over the lease term, and both are recorded as lease expense.

Liability Related to the Sales of Future Royalties and Milestones, Net

The Company recognizes a liability related to the sales of future royalties and milestones under ASC 470-10: Debt and ASC 835-30: Interest – Imputation of Interest. The initial funds received by the Company pursuant to the terms of the HCR Agreement were recorded as a liability and will be accreted under the effective interest method up to the estimated amount of future royalties and milestone payments to be made under the HCR Agreement. The issuance costs were recorded as a direct deduction to the carrying amount of the liability and will be amortized under the effective interest method over the estimated period the liability will be repaid. The Company estimated the total amount of future royalty revenue and milestone payments to be generated over the life of the HCR Agreement based on estimates and projections from CSL Vifor and Maruishi, and a significant increase or decrease in these estimates could materially impact the liability balance and the related interest expense. If the timing of the receipt of royalty and milestone

payments is materially different from the original estimates, the Company will prospectively adjust the effective interest and the related amortization of the liability and related issuance costs.

Revenue Recognition

The Company recognizes revenue in an amount that reflects the consideration to which it expects to be entitled in exchange for the transfer of promised goods or services to customers. To determine revenue recognition for contracts with customers, the Company performs the following steps: (1) identifies the contract with the customer, (2) identifies the performance obligations in the contract, (3) determines the transaction price, (4) allocates the transaction price to the performance obligations in the contract, and (5) recognizes revenue when (or as) the entity satisfies a performance obligation.

The Company has entered into agreements to license its intellectual property, or IP, related to difelikefalin to develop, manufacture and/or commercialize drug products. These agreements typically contain multiple performance obligations, including licenses of IP and R&D services. Payments to the Company under these agreements may include nonrefundable license fees, payments for research activities, payments based upon the achievement of certain milestones and royalties on any resulting net product sales. The Company receives its share of the net profits from the sale of KORSUVA injection in the United States through its license agreement with CSL Vifor. The Company has adopted a policy to recognize revenue net of tax withholdings, as applicable.

The Company identifies agreements as contracts that create enforceable rights and obligations when the agreement is approved by the parties, identifies the rights of the parties and the payment terms, has commercial substance and it is probable that the Company will collect the consideration to which it will be entitled in exchange for the goods and services that will be transferred to the customer. The counterparty is considered to be a customer when it has contracted with the Company to obtain goods and services that are the output of the Company’s ordinary activities (i.e., development of pharmaceutical products) in exchange for consideration.

A performance obligation is a promise to transfer distinct goods or services to a customer. Performance obligations that are both capable of being distinct and distinct within the context of the contract are considered to be separate performance obligations. Performance obligations are capable of being distinct if the counterparty is able to benefit from the good or service on its own or together with other resources that are readily available to it. Performance obligations are distinct within the context of the contract when each performance obligation is separately identifiable from each other; i.e., the Company is not using the goods or services as inputs to produce or deliver the combined output or outputs specified by the customer; one or more of the goods or services does not significantly modify or customize one of the other goods or services in the contract; and goods or services are not highly interdependent or not highly interrelated. Performance obligations that are not distinct are accounted for as a single performance obligation over the period that goods or services are transferred to the customer. The determination of whether performance obligations in a contract are distinct may require significant judgment.

The transaction price is the amount of consideration that the Company expects to be entitled to in exchange for transferring promised goods or services to the customer based on the contract terms at inception of a contract. There is a constraint on inclusion of variable consideration related to licenses of IP, such as milestone payments or sales-based royalty payments, in the transaction price if there is uncertainty at inception of the contract as to whether such consideration will be recognized in the future because it is probable that there will be a significant reversal of revenue in the future when the uncertainty is resolved. The determination of whether or not it is probable that a significant reversal of revenue will occur in the future depends on the likelihood and magnitude of the reversal. Factors that could increase the likelihood or magnitude of a reversal of revenue include (a) the susceptibility of the amount of consideration to factors outside the entity’s influence, such as the outcome of clinical trials, the timing of initiation of clinical trials by the counterparty and the approval of drug product candidates by regulatory agencies, (b) situations in which the uncertainty

is not expected to be resolved for a long period of time, and (c) level of the Company’s experience in the field. When it becomes probable that events will occur, for which variable consideration was constrained at inception of the contract, the Company allocates the related consideration to the separate performance obligations in the same manner as described below.

At inception of a contract, the Company allocates the transaction price to the distinct performance obligations based upon their relative standalone selling prices. Standalone selling price is the price at which an entity would sell a promised good or service separately to a customer. The best evidence of standalone selling price is an observable price of a good or service when sold separately by an entity in similar circumstances to similar customers. Since the Company typically does not have such evidence, it estimates standalone selling price so that the amount that is allocated to each performance obligation equals the amount that the Company expects to receive for transferring goods or services. The methods that the Company uses to make such estimates include (1) the adjusted market assessment approach, under which the Company forecasts and analyzes difelikefalin in the appropriate market, the phase of clinical development as well as considering recent similar license arrangements within the same phase of clinical development, therapeutic area, type of agreement, etc. and (2) the expected cost of satisfying the performance obligations plus a margin, or the expected cost plus a margin approach.

The Company recognizes revenue when, or as, it satisfies a performance obligation by transferring a promised good or service to a customer and the customer obtains control of the good or service. Revenue related to the grant of a license that is a distinct performance obligation and that is deemed to be functional IP is recognized at the point in time that the Company has the right to payment for the license, the customer has legal title to the license and can direct the use of the license (for example, to grant sublicenses), the customer has the significant risks and rewards of ownership of the license and the customer has accepted the asset (license) by signing the license agreement.

Recognition of revenue related to R&D services that are a distinct performance obligation or that are combined with granting of a license as a single performance obligation is deferred at inception of a contract and is recognized as those services are performed based on the costs incurred as a percentage of the estimated total costs to be incurred to complete the performance obligation.

The Company’s license agreements include the right to grant sub-licenses. The amount of any potential sub-license fees to be received by the Company, which is based on a formula if applicable to that respective agreement, is considered to be variable consideration and is constrained from inclusion in the transaction price at inception of the contract since at that time it was probable that there would be a reversal of such revenue in the future because the Company did not know if a sublicense would be granted in the future.

Milestone payments are considered to be variable consideration and are not included in the transaction price at inception of the contract if it is uncertain that the milestone will be achieved. Rather, when it becomes probable that the milestone will be achieved and, therefore, there will not be a significant reversal of revenue in future periods, the respective amount to be earned is included in the transaction price, allocated to the distinct performance obligations based on their relative standalone selling price and recognized as revenue, as described above. Sales milestones and sales-based royalty payments related to a license of IP are recognized as revenue when the respective sales occur.

Collaborative Revenue

Collaborative revenue includes the Company’s share of the profits generated by CSL Vifor’s sale of KORSUVA injection to third parties in the United States under its existing license agreements. The Company has adopted a policy to recognize revenue net of tax withholdings, as applicable.

The Company determined that CSL Vifor is a customer in relation to its profit share arrangement with CSL Vifor. The Company sells commercial product to CSL Vifor, who ultimately sells the commercial product to third parties. The Company’s profit share arrangement revenues generated from sales of KORSUVA injection in the United States are considered akin to sales-based royalties. In accordance with the sales-based royalty exception, the Company recognizes its share of the pre-tax commercial net profit generated from the sales of KORSUVA injection in the United States in the period the product sales are earned, as reported by CSL Vifor. The related COGS for CSL Vifor associated with the net profit share arrangement as well as the marketing and distribution fee for the applicable period reduces the Company’s profit share revenue for the period. The net sales amounts are determined based on amounts provided by CSL Vifor and involve the use of estimates and judgments, such as product sales allowances and accruals related to prompt payment discounts, and chargebacks, which could be adjusted based on actual results in the future. The Company is dependent on CSL Vifor for timely and accurate information regarding the net revenues from sales of KORSUVA injection in the United States to accurately report its results of operations. If the Company does not receive timely and accurate information or incorrectly estimates activity levels associated with the profit share arrangement at a given point in time, the Company could be required to record adjustments in future periods.

The Company records revenue transactions as net product revenue if it is deemed the principal in the transaction, which includes being the primary obligor, retaining inventory risk, and control over pricing. Given that the Company is not the primary obligor and does not have the inventory risks in the license agreement with CSL Vifor, it records its share of the net profits from the sales of KORSUVA injection in the United States on a net basis and presents the settlement payments from CSL Vifor as collaborative revenue. The Company and CSL Vifor settle the profit sharing quarterly (see Note 13,Collaboration and Licensing Agreements).

Collaborative revenue also includes milestone payments associated with the Company’s license agreement with Maruishi. Upfront and milestone payments associated with the license agreement with Maruishi are allocated between license and milestone fees and collaborative revenue based on the relative standalone selling prices determined at contract inception that were allocated to the R&D services performance obligation (see Note 14,Revenue Recognition).

Commercial Supply Revenue

Commercial supply revenue includes sales of KORSUVA injection commercial product to CSL Vifor, which ultimately acts as the principal in the net profit-sharing arrangement between the two parties since commercial launch in April 2022, which then sells to third parties in the United States. Commercial supply revenue is recognized when CSL Vifor obtains control of the Company’s commercial product, which occurs at a point in time, typically upon receipt of KORSUVA injection by CSL Vifor, and generally occurs after the commercial product has passed all quality testing required for acceptance by CSL Vifor. The Company calculates its commercial supply revenue based on its COGS plus an agreed upon margin.

License and Milestone Fees

License and milestone fees include upfront and milestone payments associated with the Company’s license agreements with CSL Vifor, Maruishi and CKDP. All upfront and milestone payments associated with the license agreements with CSL Vifor and CKDP are recognized as license and milestone fees since they contain onlyone performance obligation. Upfront and milestone payments associated with the license agreement with Maruishi are allocated between license and milestone fees and collaborative revenue based on the relative standalone selling prices determined at contract inception (see Note 14,Revenue Recognition).

Royalty Revenue

Royalty revenue includes amounts related to the Company’s royalties earned from CSL Vifor on the net sales of Kapruvia in Europe, based on the amount of net sales in a licensed territory during a calendar year. Sales-based royalty payments related to a license of IP are recognized as revenue when the respective sales occur, and the net sales tier is achieved. Beginning on October 1, 2023, royalty revenue will no longer be recognized until the Company has fulfilled its obligations under the HCR Agreement (see Note 10,Royalty Purchase and Sale Agreement).

Clinical Compound Revenue

Clinical compound revenue includes sales of clinical compound to CSL Vifor (prior to FDA approval), and Maruishi. The Company recognizes revenue on clinical compound sales when control has transferred to CSL Vifor and Maruishi, which occurs at a point in time, typically upon receipt of the clinical compound, and generally occurs after the clinical compound has passed all quality testing required for acceptance. The sales of clinical compound are reimbursed at COGS plus an agreed upon margin.

Other Revenue

Other revenue includes the royalty and milestone payments earned under Vifor Agreement No. 2 and the Maruishi Agreement in conjunction with ex-U.S. sales of KORSUVA/Kapruvia in the fourth quarter of 2023. This non-cash revenue will continue to be recorded until the Company has fulfilled its obligations under HCR Agreement.

Cost of Goods Sold (COGS)

COGS includes costs related to sales of the Company’s commercial product, KORSUVA injection, to CSL Vifor. Costs related to the sales of KORSUVA injection are generally recognized upon receipt of shipment by CSL Vifor. The Company’s COGS for KORSUVA injection includes the cost of producing commercial product that correspond with commercial supply revenue, such as third-party supply and overhead costs, as well as certain period costs related to freight, packaging, stability, and quality testing. No COGS was recognized prior to January 1, 2022, as regulatory approval of KORSUVA injection occurred in August 2021 and all inventory costs prior to regulatory approval were expensed as incurred.

Research and Development (R&D) Expenses

R&D costs are charged to expense as incurred. Costs incurred under agreements with third parties are charged to expense as incurred in accordance with the specific contractual performance terms of such agreements. R&D expenses include, among other costs, compensation and other personnel-related costs, including consultant costs, and costs to conduct clinical trials using clinical research organizations, or CROs, which include upfront, milestone and monthly expenses as well as reimbursement for pass through costs. The amount of clinical trial expense recognized in any period varies depending on the duration and progress of each clinical trial, including the required level of patient enrollment, the rate at which patients actually enroll in and drop-out of the clinical trial, and the number of sites involved in the trial as well as the activities to be performed by the sites each period. R&D costs also include costs to manufacture product candidates and clinical supplies, laboratory supplies costs, facility-related costs and stock-based compensation for R&D personnel. Non-refundable R&D advance payments are deferred and capitalized as prepaid R&D expense. The capitalized amounts are expensed as the related goods are delivered or services are performed. As of December 31, 2023 and 2022, the Company recorded $7,245 and $15,188 as prepaid R&D expense, respectively.

General and Administrative (G&A) Expenses

G&A costs are charged to expense as incurred. G&A expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in executive, finance, accounting, legal, business development, information technology, human resources, project management, alliance management, and procurement functions. Other costs include facility costs not otherwise included in R&D expenses, legal fees, insurance costs, investor relations costs, patent costs and fees for accounting and consulting services.

As noted in Note 13,Collaboration and Licensing Agreements, the Company’s license agreement with CSL Vifor provides full commercialization rights of KORSUVA injection to CSL Vifor under a profit-sharing arrangement. Under this profit-sharing arrangement, in consideration of CSL Vifor’s conduct of the marketing, promotion, selling and distribution of KORSUVA injection in the United States, the Company will pay a marketing and distribution fee to CSL Vifor based on the level of annual net sales. This fee will be deducted from product sales in calculating the net profits that are subject to the profit-sharing arrangement.

Stock-Based Compensation

The Company grants stock options to employees, non-employee members of the Company’s Board of Directors and non-employee consultants as compensation for services performed. All share-based payments, including grants of stock options, are recognized based on their grant date fair values. The grant date fair value of stock options is estimated using the Black-Scholes option valuation model.

Using this model, fair value is calculated based on assumptions with respect to (i) the fair value or market price of the Company’s common stock on the grant date; (ii) expected volatility of the Company’s common stock price, (iii) the periods of time over which employees and members of the Company’s Board of Directors or non-employee consultants are expected to hold their options prior to exercise (expected term), (iv) expected dividend yield on the Company’s common stock, and (v) risk-free interest rates.

The Company’s common stock has been traded on a public exchange only since January 31, 2014. Since that time, exercises of stock options have been limited due to various factors, including fluctuations in the Company’s stock price to below the exercise prices of awards and blackout periods during which exercises are not allowed, among others. Therefore, the Company believes that as of December 31, 2023, it does not have sufficient company-specific information available to determine the expected term based on its historical data. As a result, the expected term of stock options granted is determined using the average of the vesting period and term (6.25 years), an accepted method for the Company’s option grants under the SEC’s Staff Accounting Bulletin No. 110,Share-Based Payment.

The Company calculates the expected volatility using company-specific trading activity of its common stock over the option’s expected term. The expected dividend yield iszero as the Company has never paid dividends and does not currently anticipate paying any in the foreseeable future. Risk-free interest rates are based on quoted U.S. Treasury rates for securities with maturities approximating the option’s expected term.

The Company’s policy is to account for forfeitures of share-based payments as they occur. Compensation cost for all share-based payments granted with service-based graded vesting schedules is recognized using the straight-line method over the requisite service period.

Other income, net consists of interest and dividend income earned on the Company’s cash, cash equivalents, and marketable securities, realized gains and losses on the sale of marketable securities and property and equipment, as well

as accretion of discounts/amortization of premiums on purchases of marketable securities. In the event the Company records a credit loss expense on its available-for-sale debt securities, those expenses would be offset against other income.

Non-Cash Interest Expense on Liability Related to Sales of Future Royalties and Milestones

Non-cash interest expense on liability related to sales of future royalties and milestones consists of imputed interest on the carrying value of the liability and the amortization of the related issuance costs.

Income Taxes

The Company accounts for income taxes using the asset and liability method. Under this method, deferred tax assets and liabilities are determined based on differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Deferred income tax assets are reduced, as necessary, by a valuation allowance when management determines it is more likely than not that some or all of the tax benefits will not be realized.

There wereno material uncertain tax positions taken as of December 31, 2023 and 2022. The Company doesnot have any interest or penalties accrued related to tax positions as it does not have any unrecognized tax benefits. In the event the Company determines that accrual of interest or penalties are necessary in the future, the amount will be presented as a component of interest expense.

Loss Per Share

The Company computes basic net loss per share by dividing net loss by the weighted average number of shares of common stock outstanding. Diluted net loss per share includes the potential dilutive effect of common stock equivalents as if such securities were converted or exercised during the period, when the effect is dilutive. Common stock equivalents may include outstanding stock options and restricted stock units, which are included under the treasury stock method when dilutive. For each of the years ended December 31, 2023, 2022 and 2021, the Company excluded the effects of potentially dilutive shares that were outstanding during those respective periods from the denominator as their inclusion would have been anti-dilutive due to the Company’s net losses for those periods.

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business asone operating segment, which includes all activities related to the discovery, development, and commercialization of novel therapeutics to treat serious medical conditions, including pruritus.

Litigation Reserves

From time to time, the Company may become subject to arbitration, litigation or claims arising in the ordinary course of its business. Accruals are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. The Company reviews these reserves at least quarterly and adjusts these reserves to reflect current law, progress of each case, opinions and views of legal counsel and other advisers, the Company’s experience in similar matters and intended response to the litigation. The Company expenses amounts for administering or litigating claims as incurred. Accruals for legal proceedings, if any, are included in accounts payable and accrued expenses.

Accounting Pronouncements Recently Issued

In December 2023, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2023-09,Income Taxes (Topic 740): Improvements to Income Tax Disclosures, or ASU 2023-09, which applies to all entities subject to income taxes. ASU 2023-09 requires disaggregated information about a reporting entity’s effective tax rate reconciliation as well as information on income taxes paid. ASU 2023-09 is intended to provide more detailed income tax disclosures. For public business entities (PBEs), the new requirements will be effective for annual periods beginning after December 15, 2024. ASU 2023-09 will be applied on a prospective basis with the option to apply the standard retrospectively. The Company expects to adopt ASU 2023-09 on January 1, 2025, and it does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

In November 2023, the FASB issued ASU 2023-07,Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU 2023-07, which expands the disclosures for reportable segments made by public entities. These amendments within ASU 2023-07 retain the existing disclosure requirements in ASC 280 and expand upon them to require public entities to disclose significant expenses for reportable segments in both interim and annual reporting periods, as well as items that were previously disclosed only annually on an interim basis, including disclosures related to a reportable segment’s profit or loss and assets. In addition, entities with a single reportable segment must provide all segment disclosures required in ASC 280, including the new disclosures for reportable segments under the amendments in ASU 2023-07. The amendments do not change the existing guidance on how a public entity identifies and determines its reportable segments. A public entity should apply the amendments in ASU 2023-07 retrospectively to all prior periods presented in the financial statements. Upon transition, the segment expense categories and amounts disclosed in the prior periods should be based on the significant segment expense categories identified and disclosed in the period of adoption. The amendments in ASU 2023-07 are effective for annual periods for all public entities in fiscal years beginning after December 15, 2023, and in interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The Company will adopt ASU 2023-07 on January 1, 2024, and it does not expect the adoption to have a material effect on its results of operations, financial position, and cash flows.

3. Available-for-Sale Marketable Securities

As of December 31, 2023 and 2022, the Company’s available-for-sale marketable securities consisted of debt securities issued by the U.S. Treasury, U.S. government-sponsored entities and investment grade institutions (corporate bonds). As of December 31, 2022, the Company’s available-for-sale marketable securities also consisted of debt securities issued by investment grade institutions (commercial paper) and municipal bonds.

The following tables summarize the Company’s available-for-sale marketable securities by major type of security as of December 31, 2023 and 2022:

As of December 31, 2023

As of December 31, 2022

The following tables summarize the fair value and gross unrealized losses of the Company’s available-for-sale marketable securities by investment category and disaggregated by the length of time that individual debt securities have been in a continuous unrealized loss position as of December 31, 2023 and 2022:

As of December 31, 2023

As of December 31, 2022

As of December 31, 2023 and 2022, respectively, no allowance for credit losses were recognized on the Company’s available-for-sale debt securities asno portion of the unrealized losses associated with those securities were due to credit losses. The information that the Company considered in reaching the conclusion that an allowance for credit losses was not necessary for the following categories of securities is as follows:

As of December 31, 2023 and 2022, the Company held a total of 3 out of 9 positions and 35 out of 39 positions, respectively, that were in an unrealized loss position, all of which had been in an unrealized loss position for 12 months or greater as of December 31, 2023. Unrealized losses individually and in aggregate, including any in an unrealized loss position for 12 months or greater, were not considered to be material for each respective period. Based on the Company’s review of these securities, the Company believes that the cost basis of its available-for-sale marketable securities is recoverable.

**U.S. Treasury securities and U.S. government agency obligations.**The unrealized losses on the Company’s investments in direct obligations of U.S. Treasury securities and U.S. government agencies were due to changes in

interest rates and non-credit related factors. The credit ratings of these investments in the Company’s portfolio have not been downgraded below investment grade status. The contractual terms of these investments do not permit the issuer to repay principal at a price less than the amortized cost bases of the investments, which is equivalent to the par value on the maturity date. The Company expects to recover the entire amortized cost bases of these securities on the maturity date. The Company does not intend to sell these investments, and it is not “more likely than not” that the Company will be required to sell these investments before recovery of their amortized cost bases. The Company held 0 out of 5 positions for its U.S. Treasury securities and 2 out of 2 positions for its U.S. government agency obligations, that were in unrealized loss positions as of December 31, 2023.

Corporate bonds. The unrealized losses on the Company’s investments in corporate bonds were due to changes in interest rates and non-credit related factors. The credit ratings of these investments in the Company’s portfolio have not been downgraded below investment grade status. The contractual terms of these investments do not permit the issuer to repay principal at a price less than the amortized cost bases of the investments, which is equivalent to the par value on the maturity date. The Company expects to recover the entire amortized cost bases of these securities on the maturity date. The Company does not intend to sell these investments, and it is not “more likely than not” that the Company will be required to sell these investments, before recovery of their amortized cost bases. The Company held 1 out of 2 positions for its corporate bonds, that were in unrealized loss positions as of December 31, 2023.

The Company classifies its marketable debt securities based on their contractual maturity dates. As of December 31, 2023, the Company’s marketable debt securities mature at various dates through November 2024. The amortized cost and fair values of marketable debt securities by contractual maturity were as follows:

All available-for-sale marketable securities are classified as marketable securities, current or marketable securities, non-current depending on the contractual maturity date of the individual available-for-sale security. Other income, net includes interest and dividends, accretion/amortization of discounts/premiums, realized gains and losses on sales of securities and credit loss expense due to declines in the fair value of securities, if any. The cost of securities sold is based on the specific identification method.

There wereno sales of available-for-sale marketable securities during the years ended December 31, 2023 and 2022. During the year ended December 31, 2021, the Company sold certain of its available-for-sale debt securities with a total fair value of $10,029, which resulted in realized gains of $39.

As of December 31, 2023 and 2022, accrued interest receivables on our available-for-sale debt securities were $139 and $489, respectively.

4. Accumulated Other Comprehensive (Loss) Income

The following table summarizes the changes in accumulated other comprehensive (loss) income, net of tax, from unrealized gains (losses) on available-for-sale marketable securities, the Company’s only component of accumulated other comprehensive (loss) income, for the years ended December 31, 2023, 2022 and 2021.

Amounts reclassified out of accumulated other comprehensive (loss) income into net loss are determined by specific identification. The reclassifications out of accumulated other comprehensive (loss) income and into net loss were as follows:

5. Inventory, net

Inventories consist of the following:

As of December 31, 2023 and December 31, 2022, inventory balances include inventory costs subsequent to regulatory approval of KORSUVA injection on August 23, 2021. During the years ended December 31, 2023 and 2022,

the Company wrote down $526 and $34, respectively, of commercial supply inventory due to obsolescence. There wereno write-downs of commercial supply inventory during the year ended December 31, 2021.

6. Prepaid Expenses

As of December 31, 2023, the amount of prepaid expenses was $8,154, consisting of $7,245 of prepaid R&D clinical costs, $492 of prepaid insurance and $417 of other costs. As of December 31, 2022, the amount of prepaid expenses was $16,267, consisting of $15,188 of prepaid R&D clinical costs, $543 of prepaid insurance and $536 of other costs.

7. Property and Equipment, net

Property and equipment, net consists of the following:

Leasehold improvements include $2,533 relating to the New Lease entered into in May 2023 that are still in process as of December 31, 2023 and will begin amortization once the improvements are complete. In October and November 2023, the Company determined that $1,755 of these costs qualified for reimbursement as lease incentives, of which $808 had been reimbursed to the Company as of December 31, 2023 (see Note 19,*Commitments and Contingencies -*Lease (New Corporate Headquarters in May 2023).

Depreciation and amortization expense included in R&D expense and G&A expense was $259, $248 and $248 for the years ended December 31, 2023, 2022 and 2021, respectively.

There wereno gains or losses on sales of property and equipment during the years ended December 31, 2023 and 2022. During the year ended December 31, 2021, the Company sold laboratory equipment that was fully depreciated, which resulted in gains on sales of property and equipment of $70.

8. Restricted Cash

In May 2023, the Company entered into the New Lease with 400 Atlantic Joint Venture LLC and SLJ Atlantic Stamford LLC (tenants-in-common), or the Landlord, for the lease of 26,374 square feet of office space located at 400 Atlantic Street, Stamford, Connecticut 06901 for its new principal offices. The Company is required to maintain a stand-by letter of credit as a security deposit under the New Lease for its office space in Stamford, Connecticut (refer to Note 19,Commitments and Contingencies: Leases). The fair value of the letter of credit approximates its contract value. The Company’s bank requires the Company to maintain a restricted cash balance to serve as collateral for the letters of credit issued to the landlord by the bank for the New Lease and the previous Stamford Lease. As of December 31, 2023, the restricted cash balance for the New Lease and the Stamford Lease was invested in a commercial money market account.

As of December 31, 2023, the Company had $408 of restricted cash related to the Stamford Lease (which was terminated in December 2023 but not yet released) that became unrestricted in January 2024 and $1,500 of restricted cash related to the New Lease in long-term assets. After the first and second anniversaries of the rent commencement date, the face amount of the letter of credit relating to the New Lease can be reduced by $500 each period if the Company is not in default of its lease obligations. As of December 31, 2022, the Company had $408 of restricted cash related to the Stamford Lease in current assets.

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Consolidated Statements of Cash Flows.

9. Accounts Payable and Accrued Expenses

Accounts payable and accrued expenses consist of the following:

10. Royalty Purchase and Sale Agreement

During the fourth quarter of 2023, the Company, through its wholly-owned subsidiary Cara Royalty Sub, LLC, a Delaware limited liability company, or Cara Royalty Sub, entered into the HCR Agreement with HCR, pursuant to which Cara Royalty Sub sold, or agreed to sell, to HCR certain of its rights to receive royalty payments, or the Royalties, due and payable to Cara Royalty Sub (as assignee of the Company) under the Maruishi Agreement and Vifor Agreement No. 2., collectively the Covered License Agreements, in exchange for up to$40,000. The Company has retained all of its right, title and interest in, to and under the Covered License Agreements that relate to any non-intravenous formulation of difelikefalin.

Under the terms of the HCR Agreement, Cara Royalty Sub received an upfront payment of $16,915 in November 2023, representing the $17,500 to which the Company was initially entitled, net of advisory fees and certain of HCR’s transaction-related expenses which the Company agreed to reimburse. In December 2023, Cara Royalty Sub received an additional payment of $19,770, representing the $20,000 milestone it achieved for Kapruvia (difelikefalin) pricing in Germany being approved above a certain threshold amount per dose, net of advisory fees. There were additional issuance costs of $211 related to the HCR Agreement resulting in aggregate net proceeds of $36,474. An additional $2,500 milestone payment is due to Cara Royalty Sub upon achievement of a 2024 sales milestone of KORSUVA in Japan.

The HCR Agreement will automatically expire, and the payment of Royalties to HCR will cease, when HCR has received payments of Royalties equal totwo times the aggregate amount of payments made by HCR under the HCR Agreement if achieved on or prior to December 31, 2029, or 2.8 times the aggregate amount of payments made by HCR under the HCR Agreement, if not achieved on or prior to December 31, 2029. After the HCR Agreement expires, all rights to receive the Royalties return to Cara Royalty Sub.

Issuance costs pursuant to the HCR Agreement consisting primarily of advisory and legal fees totaled $1,025 including the amount of HCR’s transaction-related expenses that the Company reimbursed. The effective interest rate includes cash flow projections for future royalty and milestone payments, which are sensitive to certain assumptions, including market size, market penetration and sales price, that are forward looking and could be affected by future market conditions.

The following table summarizes the activity of the HCR Agreement (in thousands):

11. Stockholders’ Equity

The Company’s Board of Directors has authorized 100,000,000 shares of the Company’s common stock, par value $0.001 per share, and 5,000,000 shares of undesignated preferred stock, par value $0.001 per share, that may be issued from time to time by the Board of Directors of the Company in one or more series. As of December 31, 2023, there were 54,480,704 shares ofcommon stock andno shares of preferred stock issued andoutstanding.

Each share of common stock entitles the holder toone vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are entitled to dividends when and if declared by the Board of Directors, subject to the preferential rights of the holders of preferred stock, if any.

In October 2023, as a result of completion of the quarterly vesting period for restricted stock units granted in October 2021, an aggregate of 8,875 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In August 2023, as a result of completion of the vesting period for restricted stock units granted in October 2022, an aggregate of 7,267 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In July 2023, as a result of completion of the quarterly vesting period for restricted stock units granted in October 2021, an aggregate of 8,875 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In June 2023, as a result of completion of the final vesting period for restricted stock units granted in December 2021, an aggregate of 26,199 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In June 2023, as a result of the completion of theone-year vesting period, an aggregate of 59,380 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In April 2023, as a result of completion of the quarterly vesting period for restricted stock units granted in October 2021, an aggregate of 8,875 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In March 2023, as a result of the completion of the second year of thethree-year vesting period for restricted stock units granted in March 2021, an aggregate of 15,999 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In February 2023, as a result of the completion of the first year of thethree-year vesting period for restricted stock units granted in February 2022, an aggregate of 42,920 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

Also in February 2023, as a result of the completion of the third year of thethree-year vesting period for restricted stock units granted in February 2020, an aggregate of 15,999 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In January 2023, as a result of completion of the quarterly vesting period for restricted stock units granted in October 2021, an aggregate 8,875 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In December 2022, as a result of the achievement of certain performance targets, an aggregate of 26,204 performance-based restricted stock units of certain employees vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In October 2022, as a result of the completion of the first year of vesting associated with awards granted to the Company’s new Chief Executive Officer, or CEO, an aggregate of 35,500 restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In September 2022, as a result of the appointment of the Company’s new Chief Financial Officer, or CFO,7,500 time-based restricted stock units held by the Company’s interim principal financial and accounting officer vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In June 2022, as a result of the accelerated vesting of restricted stock units previously granted to the Company’s former CEO, an aggregate of 33,999 restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In June 2022, as a result of the completion of theone-year vesting period, an aggregate of 43,200 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock. Also in June 2022, the Company granted 11,876 fully vested restricted stock units, which were immediately settled in shares of common stock, to the Company’s chairman in consideration of his effort in connection with the Company’s CEO transition in 2021 (see Note 15,Stock-Based Compensation).

In March 2022, as a result of the achievement of certain performance targets, an aggregate of 37,999 performance-based restricted stock units of certain employees vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In March 2022, as a result of the completion of the first year of thethree-year vesting period for restricted stock units granted in March 2021 and the full vesting of the second tranche of restricted stock units granted to the new CEO in October 2021, an aggregate of 39,278 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In March 2022, the Company filed a universal shelf registration statement, or the Shelf Registration Statement, which provides for aggregate offerings of up to $300,000 of common stock, preferred stock, debt securities, warrants or any combination thereof. The Shelf Registration Statement was declared effective on May 11, 2022. The securities registered under the Shelf Registration Statement include $154,525 of unsold securities that had been registered under the Company’s previous Registration Statement on Form S-3 (File No. 333-230333) that was declared effective on April 4, 2019.

Also in March 2022, the Company entered into the Sales Agreement, pursuant to which it may, from time to time, issue and sell common stock with an aggregate value of up to $80,000 in an at-the-market offering pursuant to the Shelf Registration Statement. Jefferies is acting as sole sales agent for any sales made under the Sales Agreement for a 3% commission on gross proceeds. The common stock will be sold at prevailing market prices at the time of the sale, and, as a result, prices may vary. Unless otherwise terminated earlier, the Sales Agreement continues until all shares available under the Sales Agreement have been sold. During the year ended December 31, 2023,386,881 shares were sold under the Sales Agreement and the Company received net proceeds of $1,117.

The Company may offer additional securities under its Shelf Registration Statement from time to time in response to market conditions or other circumstances if it believes such a plan of financing is in the best interests of its stockholders.

In February 2022, as a result of the completion of the second year of thethree-year vesting period for restricted stock units granted in February 2020, an aggregate of 32,666 time-based restricted stock units vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In October 2021, the Company issued 3,282,391 shares of its common stock to Vifor International in connection with the milestone earned for the U.S. regulatory approval of KORSUVA injection in August 2021 (see Note 13,Collaboration and Licensing Agreements).

In August 2021, as a result of the achievement of certain performance targets, an aggregate of 44,002 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In June 2021, as a result of the completion of theone-year vesting period, an aggregate of 36,000 restricted stock units of members of the Board of Directors vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In February and March 2021, as a result of the achievement of certain performance targets, an aggregate of 76,750 performance-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

In February 2021, as a result of the completion of the first year of thethree-year vesting period, an aggregate of 32,669 time-based restricted stock units of various executive officers vested and were settled in shares of the Company’s common stock (see Note 15,Stock-Based Compensation).

12. Fair Value Measurements

The following tables summarize the Company’s financial assets measured at fair value on a recurring basis as of December 31, 2023 and 2022, and by level within the fair value hierarchy:

Fair value measurement as of December 31, 2023:

Fair value measurement as of December 31, 2022:

There wereno purchases, sales or maturities of Level 3 financial assets andno unrealized gains or losses related to Level 3 available-for-sale marketable securities for the years ended December 31, 2023, 2022 and 2021. There wereno transfers of financial assets between Levels 1, 2, or 3 classifications during the years ended December 31, 2023 and 2022.

13. Collaboration and Licensing Agreements

Vifor (International) Ltd. (Vifor International)

In October 2020, the Company entered into a license agreement with Vifor International, or Vifor Agreement No. 1, under which the Company granted Vifor International an exclusive license solely in the United States to use, distribute, offer for sale, promote, sell and otherwise commercialize difelikefalin injection for all therapeutic uses

relating to the inhibition, prevention or treatment of itch associated with pruritus in hemodialysis and peritoneal dialysis patients in the United States. Under Vifor Agreement No. 1, the Company retains all rights with respect to the clinical development of, and activities to gain regulatory approvals of, difelikefalin injection in the United States. The Joint Commercialization Committee, or JCC, have the responsibility for overall coordination and oversight of Vifor International (and any affiliates or sublicensees). The Company’s membership on the JCC is at its sole discretion and is not its obligation.

After the assignment of rights of Vifor Agreement No. 1 from Vifor International to Vifor Fresenius Medical Care Renal Pharma Ltd. in May 2022, Vifor Agreement No. 1 provides full commercialization rights in dialysis clinics to CSL Vifor in the United States under a profit-sharing arrangement. Pursuant to the profit-sharing arrangement, the Company is generally entitled to 60% of the net profits (as defined in Vifor Agreement No. 1) from sales of difelikefalin injection in the United States and CSL Vifor is entitled to 40% of such net profits (excluding sales to Fresenius Medical Center dialysis clinics, compensation for which is governed by Vifor Agreement No. 2, as defined below), subject to potential temporary adjustment in future years based on certain conditions. Under Vifor Agreement No. 1, in consideration of CSL Vifor’s conduct of the marketing, promotion, selling and distribution of difelikefalin injection in the United States, the Company pays a marketing and distribution fee to CSL Vifor based on the level of annual net sales. This fee as well as CSL Vifor’s COGS are deducted from net sales in calculating the net profits that are subject to the profit-sharing arrangement under Vifor Agreement No. 1.

After U.S. regulatory approval of KORSUVA injection in August 2021, the Company received $50,000 in October 2021 for the purchase of an aggregate of 3,282,391 shares of the Company’s common stock at a price of $15.23 per share, which represented a 20% premium to the 30-day trailing average price of the Company’s common stock as of the date of the achievement of the milestone. The purchase of the Company’s common stock was governed by a separate stock purchase agreement, or the Vifor Stock Purchase Agreement. The excess of the stock purchase price over the cost of the purchased shares at the closing price of the Company’s common stock on the date of the achievement of the milestone of $5,031 was included as license and milestone fees revenue for accounting purposes (see Note 14,Revenue Recognition – License and Milestone Fees).

In addition, pursuant to Vifor Agreement No. 1, the Company is eligible to receive payments of up to $240,000 from CSL Vifor upon the achievement of certain sales-based milestones.

The license also requires CSL Vifor to promote and take orders for difelikefalin injection, or Licensed Product, throughout the United States, including coordinating with CSL Vifor promotional activities to FMC U.S. Dialysis Clinics which are subject to the Company’s rights under Vifor Agreement No. 2. The license also allows CSL Vifor to grant sub-licenses, which, in certain cases, requires the Company’s prior written consent. The Company retains the rights to import, distribute, promote, sell and otherwise commercialize the Licensed Product on an exclusive basis outside of the Field either in or outside of the United States.

The Company retains the rights to make and have made the Licensed Product, on a non-exclusive basis, in the United States for commercial sale of the Licensed Product for use for all therapeutic uses to prevent, inhibit or treat itch associated with pruritus in hemodialysis and peritoneal-dialysis patients, or the Field, anywhere in the world and for supply of Licensed Product to CSL Vifor under the terms of a supply agreement, or the Vifor International Supply Agreement, which was executed in September 2021. The supply price is the Company’s COGS, as calculated under GAAP, plus an agreed upon margin. The Vifor International Supply Agreement will co-terminate with Vifor Agreement No. 1.

The Vifor International Supply Agreement is accounted for as a customer option that is not a material right because the selling price of the Licensed Product under the Vifor International Supply Agreement is the Company’s COGS plus an agreed upon margin, which is commensurate with the “COGS plus” model that the Company would

charge other parties under similar agreements (the standalone selling price) and not at a discount. Therefore, the sale of commercial supply to CSL Vifor is not a performance obligation under Vifor Agreement No. 1 but rather the Vifor International Supply Agreement is a separate agreement from Vifor Agreement No. 1. The only performance obligation under the Vifor International Supply Agreement is the delivery of the Licensed Product to CSL Vifor for commercialization.

Vifor Agreement No. 1 will continue in effect until its expiration upon the cessation of commercial sale of difelikefalin injection in the United States by CSL Vifor and its affiliates and sublicensees, or until the earlier termination of Vifor Agreement No. 1.

Vifor Agreement No. 1 may be terminated earlier by either party for material breach that is not cured within 60 days, bankruptcy by either party and by both parties upon mutual written consent. The Company may terminate Vifor Agreement No. 1 if CSL Vifor challenges the validity of any licensed patent rights, except if such patent challenge results from the Company’s action against CSL Vifor for infringement of any licensed patent in the United States. In addition, upon the earlier of (1) the acceptance for filing of an NDA covering Licensed Product filed with the FDA (after completion of the Phase 3 program) or (2) the third anniversary of the Effective Date, Vifor Agreement No. 1 may be terminated by CSL Vifor in its entirety upon written notice to the Company. Such termination will be effective twelve months following the date of such notice.

Vifor Fresenius Medical Care Renal Pharma Ltd.

In May 2018, the Company entered into a license agreement with Vifor Fresenius Medical Care Renal Pharma Ltd., or Vifor Agreement No. 2, under which the Company granted Vifor Fresenius Medical Care Renal Pharma Ltd. an exclusive, royalty-bearing license, or the Vifor License, to seek regulatory approval to commercialize, import, export, use, distribute, offer for sale, promote, sell and otherwise commercialize the Licensed Product in the Field worldwide (excluding the United States, Japan and South Korea), or the Territory. Vifor Fresenius Medical Care Renal Pharma Ltd. cannot perform development activities on their own unless specifically allocated to Vifor Fresenius Medical Care Renal Pharma Ltd. by the Joint Development Committee, or JDC, and Joint Steering Committee, or JSC. The Company’s membership on the JSC or JDC is at its sole discretion and is not its obligation.

The Company was responsible, at its own cost, to undertake clinical and non-clinical development, or the R&D services. The Company was also responsible to provide all content and subject matter expertise required for registration with the European Medicines Agency, or EMA, in the EU that will be needed by Vifor Fresenius Medical Care Renal Pharma Ltd. for such registration, including participation in regulatory meetings, as needed. CSL Vifor contributed, at its own cost, its clinical development expertise as reasonably useful for such development activities, such as preparing the clinical results that the Company presents to it in a format acceptable to the EMA to obtain marketing approval in the EU.

As a result of the European Commission’s regulatory approval of Kapruvia in April 2022, the Company received a $15,000 regulatory milestone payment from Vifor Fresenius Medical Care Renal Pharma Ltd. under Vifor Agreement No. 2 during the year ended December 31, 2022. In addition, after U.S. regulatory approval of KORSUVA injection in August 2021, the Company earned a $15,000 regulatory milestone payment from Vifor Fresenius Medical Care Renal Pharma Ltd. under Vifor Agreement No. 2 during the year ended December 31, 2021.

The Company is eligible to receive from Vifor Fresenius Medical Care Renal Pharma Ltd. additional commercial milestone payments in the aggregate of up to $440,000, all of which are sales related. The Company is also eligible to receive tiered double-digit royalty payments based on annual net sales, as defined in Vifor Agreement No. 2, of difelikefalin injection in the licensed territories. The Company retains full commercialization rights for difelikefalin injection for the treatment of CKD-aP in the United States except in the dialysis clinics of FMCNA, where Vifor

Fresenius Medical Care Renal Pharma Ltd. promotes difelikefalin injection under a profit-sharing arrangement (as defined in Vifor Agreement No. 2) based on net FMCNA clinic sales (as defined in Vifor Agreement No. 2) and Vifor Fresenius Medical Care Renal Pharma Ltd. is entitled to 50% of such net profits, subject to potential adjustments in a calendar year based on certain conditions.

The license also requires Vifor Fresenius Medical Care Renal Pharma Ltd. to promote and take orders in the United States for sale by the Company to FMC U.S. Dialysis Clinics and allows Vifor Fresenius Medical Care Renal Pharma Ltd. to grant sub-licenses, which, in certain cases, requires the Company’s prior written consent. The Company retains the rights to import, distribute, promote, sell and otherwise commercialize the Licensed Product outside of the Field and outside of the Territory.

The Company retains the rights to make and have made the Licensed Product in the Territory for commercial sale by Vifor Fresenius Medical Care Renal Pharma Ltd. in the Field in or outside the Territory and for supply of Licensed Product to Vifor Fresenius Medical Care Renal Pharma Ltd. under the terms of a supply agreement, or the Vifor Supply Agreement, which was executed in May 2020. The supply price is the Company’s COGS, as calculated under U.S. GAAP, plus an agreed upon margin. The Vifor Supply Agreement will co-terminate with the Vifor Agreement No. 2.

The Vifor Supply Agreement is accounted for as a customer option that is not a material right because the selling price of the Licensed Product under the Vifor Supply Agreement is the Company’s COGS plus an agreed upon margin, which is commensurate with the “COGS plus” model that the Company would charge other parties under similar agreements (the standalone selling price) and not at a discount. Therefore, the sale of clinical compound to Vifor Fresenius Medical Care Renal Pharma Ltd. is not a performance obligation under Vifor Agreement No. 2 but rather the Vifor Supply Agreement is a separate agreement from Vifor Agreement No. 2. The only performance obligation under the Vifor Supply Agreement is the delivery of the Licensed Product to Vifor Fresenius Medical Care Renal Pharma Ltd. for commercialization.

Vifor Agreement No. 2 terminates upon the expiration of all royalty terms with respect to the Licensed Products, which expire on a Product-by-Product and country-by-country basis, at the latest of (a) the expiration of all patent rights licensed to Vifor Fresenius Medical Care Renal Pharma Ltd. covering such Licensed Product; (b) the expiration of all regulatory and data exclusivity applicable to such Licensed Product in such country and (c) the tenth anniversary of the first commercial sale of such Product in such country.

Vifor Agreement No. 2 may be terminated earlier by either party for material breach that is not cured within 60 days, bankruptcy by either party and by both parties upon mutual written consent. The Company may terminate Vifor Agreement No. 2 if Vifor Fresenius Medical Care Renal Pharma Ltd. challenges the validity of any licensed patent rights, except if such patent challenge results from the Company’s action against Vifor Fresenius Medical Care Renal Pharma Ltd. for infringement of any licensed patent in the Territory. In addition, upon the earlier of (1) the acceptance for filing of an NDA covering Licensed Product filed with the FDA (after completion of the Phase 3 program) or (2) the third anniversary of the Effective Date, Vifor Agreement No. 2 may be terminated by Vifor Fresenius Medical Care Renal Pharma Ltd. in its entirety or with respect to any countries within the Territory upon written notice to the Company. Such termination will be effective twelve months following the date of such notice.

If Vifor Agreement No. 2 terminates early for any reason stated above, Vifor Fresenius Medical Care Renal Pharma Ltd.’s licenses will terminate, Vifor Fresenius Medical Care Renal Pharma Ltd.’s rights to use the Company’s confidential information and the Company’s know-how will revert to the Company and Vifor Fresenius Medical Care Renal Pharma Ltd. will assign and transfer to the Company all right, title and interest in all regulatory applications (IND’s and NDA’s), regulatory approval applications and regulatory approvals in the Territory covering Licensed Product.

Maruishi Pharmaceutical Co., Ltd. (Maruishi)

In April 2013, the Company entered into a license agreement with Maruishi, or the Maruishi Agreement, under which the Company granted Maruishi an exclusive license to develop, manufacture, and commercialize drug products containing difelikefalin for acute pain and/or uremic pruritus in Japan. Maruishi has the right to grant sub-licenses in Japan, which entitles the Company to receive sub-license fees, net of prior payments made by Maruishi to the Company. Under the Maruishi Agreement, the Company and Maruishi are required to use commercially reasonable efforts, at their own expense, to develop, obtain regulatory approval for and commercialize difelikefalin in the United States and Japan, respectively. In addition, the Company provided Maruishi specific clinical development services for difelikefalin used in Maruishi’s field of use.

Under the terms of the Maruishi Agreement, the Company is eligible to receive milestone payments upon the achievement of defined clinical and regulatory events as well as tiered, low double-digit royalties with respect to any sales of the licensed product sold in Japan by Maruishi, if any, and share in any sub-license fees.

The Maruishi Agreement continues until terminated. Either the Company or Maruishi may terminate the Maruishi Agreement for the other party’s breach of the agreement or bankruptcy. Maruishi may terminate the agreement at any time at will. The Company may terminate the agreement as a whole if Maruishi challenges the licensed patent rights, and it may terminate the agreement with respect to any indication if Maruishi discontinues its development activities.

In September 2022, Maruishi submitted a New Drug Application in Japan for approval of difelikefalin injection for the treatment of pruritus in hemodialysis patients. In September 2023, Maruishi received manufacturing and marketing approval from Japan’s Ministry of Health, Labour and Welfare for KORSUVA IV Injection Syringe for the treatment of pruritus in hemodialysis patients. In conjunction with the approval, the Company earned a $1,449 milestone payment per the terms of the licensing agreement (see Note 14*, Revenue Recognition)*. In November 2023, the Company entered into an API supply agreement with Maruishi for difelikefalin.

Chong Kun Dang Pharmaceutical Corporation (CKDP)

In April 2012, the Company entered into a license agreement with CKDP, or the CKDP Agreement, in South Korea, under which the Company granted CKDP an exclusive license to develop, manufacture and commercialize drug products containing difelikefalin in South Korea. The Company and CKDP are each required to use commercially reasonable efforts, at their respective expense, to develop, obtain regulatory approval for and commercialize difelikefalin in the United States and South Korea, respectively.

Under the terms of the CKDP Agreement, the Company is eligible to receive milestone payments upon the achievement of defined clinical and regulatory events as well as tiered royalties, with percentages ranging from the high single digits to the high teens, based on net sales of products containing difelikefalin in South Korea, if any, and share in any sub-license fees.

The CKDP Agreement continues until CKDP no longer has any obligation to pay the Company royalties on any product. Either the Company or CKDP may terminate the CKDP Agreement for the other party’s breach of the CKDP Agreement or bankruptcy. CKDP may terminate the CKDP Agreement if any of the licensed patent rights is invalid, unenforceable, is narrowed in scope or is deemed unpatentable, except as a result of a challenge by CKDP, or a third party commercializes a product containing a compound identical to difelikefalin without infringing any of the licensed patent rights in South Korea. The Company may terminate the CKDP Agreement if CKDP challenges the licensed patent rights or if a third party in South Korea owns an issued patent that claims difelikefalin and CKDP’s sale of products would infringe that patent.

14. Revenue Recognition

The Company has primarily recognized revenue under its license and collaboration agreements from (1) its share of the profit generated by KORSUVA injection sales in the United States; (2) upfront license fees and milestone payments, including development and regulatory milestones; (3) commercial supply revenue from CSL Vifor; (4) royalty revenue from net sales of Kapruvia; and (5) clinical compound sales from certain license agreements. As of December 31, 2023, the Company has not earned any sales-based milestones under its collaboration agreements.

As of December 31, 2023, the Company had license and collaboration agreements with CSL Vifor, Maruishi and CKDP. The following table provides amounts included in the Company’s Consolidated Statements of Comprehensive Loss as revenue for the years ended December 31, 2023, 2022 and 2021:

• Includes amounts earned from Vifor Fresenius Medical Care Renal Pharma Ltd. and Vifor International prior to Vifor International’s assignment of its rights and obligations to Vifor Fresenius Medical Care Renal Pharma Ltd. in May 2022.

Collaborative revenue

Beginning in April 2022, the Company began recording its share of the profit generated by KORSUVA injection sales by CSL Vifor to third parties in the United States. Under the license agreements with CSL Vifor, KORSUVA injection net sales are calculated by CSL Vifor which are net of discounts, rebates, and allowances. These amounts include the use of estimates and judgments, which could be adjusted based on actual results in the future. The Company records its share of the net profits from the sales of KORSUVA injection in the United States on a net basis (since the Company is not the primary obligor and does not retain inventory risk) and presents the revenue earned each period as

collaborative revenue. During the years ended December 31, 2023 and 2022, the Company recorded $12,397 and $16,572, respectively, as collaborative revenue for its profit-share from the sales of KORSUVA injection in the United States. There wasno profit share revenue recorded during the year ended December 31, 2021.

The Company’s distinct performance obligations under the Maruishi Agreement included transfer of the license to the Company’s IP, which allowed Maruishi to develop and commercialize difelikefalin, for acute pain and uremic pruritus indications in Japan, which occurred at inception of the contract in 2013 (considered license and milestone fees revenue), and performance of R&D services, which occurred from 2013 to 2015 (considered collaborative revenue), as those services were rendered. The Company agreed to conduct limited work on an oral tablet formulation of difelikefalin and to conduct Phase 1 and proof-of-concept Phase 2 clinical trials of an intravenous formulation of difelikefalin to be used to treat patients with uremic pruritus. The Company agreed to transfer the data and information from such development to Maruishi for its efforts to obtain regulatory approval in Japan. These activities are referred to as R&D services and were included as collaborative revenue.

In addition, the Company’s promise in the Maruishi Agreement to transfer the license is separately identifiable from the promise to provide defined R&D services (i.e., distinct within the context of the contract) because the Company was not using the goods or services as inputs to produce or deliver the combined output or outputs specified by the customer. The combined output specified by Maruishi is its right to conduct development activities related to difelikefalin in Japan, which could result in regulatory approval in Japan. That right is derived from the Company’s grant of the license. Maruishi is conducting clinical trials on its own and does not require the R&D services provided by the Company. Furthermore, the R&D services do not significantly modify or customize the license and vice versa. Finally, the license and R&D services were not highly interdependent or highly interrelated because the Company was able to fulfill its promise to transfer the initial license independently from its promise to subsequently provide the R&D services, which Maruishi can obtain on its own. There wereno remaining performance obligations under the Maruishi Agreement as of December 31, 2023.

During the year ended December 31, 2023, the criteria for revenue recognition for a regulatory milestone event set forth in the Maruishi Agreement was achieved, and the Company earned $1,449, of which $539 was recorded as collaborative revenue based on the relative standalone selling prices described at contract inception. This regulatory milestone payment was considered variable consideration due to the uncertainty of occurrence of this event as specified at inception of the agreement. Therefore, this potential regulatory milestone payment was not included in the transaction price at the inception of the agreement. There wasno collaborative revenue recognized under the Maruishi Agreement during the year ended December 31, 2022. During the year ended December 31, 2021, the criteria for revenue recognition for a milestone event set forth in the Maruishi Agreement was achieved, and the Company recorded $706 as collaborative revenue based on the relative standalone selling prices described above at contract inception (see Note 2,Summary of Significant Accounting Policies – Revenue Recognition).

Commercial supply revenue

Under the Vifor International Supply Agreement, the Company’s only performance obligation is the delivery of KORSUVA injection to CSL Vifor in accordance with the receipt of purchase orders. Revenue from the sale of commercial supply product to CSL Vifor is recognized as delivery of the Licensed Product occurs. The Company had commercial supply revenue of $5,843 with associated COGS of $6,174 since these inventory costs were capitalized as inventory subsequent to regulatory approval. The Company had commercial supply revenue of $10,223 for the year ended December 31, 2022, of which $2,295 was recognized in January 2022 withno associated COGS since these inventory costs were incurred prior to regulatory approval on August 23, 2021, and $7,928 was recognized throughout the remainder of 2022 with associated COGS of $7,266 since these inventory costs were capitalized as inventory subsequent to regulatory approval.

The Company had $701 of commercial supply revenue for the year ended December 31, 2021 withno associated COGS since these inventory costs were incurred prior to regulatory approval on August 23, 2021.

License and milestone fees revenue

Under Vifor Agreement No. 2, the Company identifiedtwo performance obligations at contract inception in 2018: (1) granting of the license to CSL Vifor, and (2) the R&D services. The Company determined that thesetwo performance obligations were not capable of being distinct (i.e., did not have standalone value for CSL Vifor) because CSL Vifor could not benefit (derive potential cash flows) from either one on its own or together with other resources that are readily available to it since CSL Vifor was relying on the Company’s expertise in investigating chronic kidney disease-associated pruritus, or CKD-aP, and its know-how obtained from multiple years of pre-clinical and clinical development, and years of interactions with the FDA which other companies or CROs would not have. The license to CSL Vifor did not provide benefit to CSL Vifor until and unless the Company conducted the pivotal clinical trials and other supportive trials in CKD-aP to gather sufficient clinical data for CSL Vifor to obtain marketing approval in the Territory. Furthermore, CSL Vifor did not have the right to perform development activities on its own unless specifically allocated by the JDC or JSC.

Thetwo identified performance obligations were also not distinct within the context of the contract, (i.e., were not separately identifiable from each other) because of the nature of the promise within the context of the contract. The nature of the promise was to transfer a combined deliverable to CSL Vifor based on the agreement (to support the ability of CSL Vifor to commercialize the Licensed Product) and the Company determined that the license granted to CSL Vifor and the R&D services are inputs rather than a transfer of each of these goods and services individually. In addition, thetwo identified performance obligations were highly interrelated and interdependent because satisfaction of both performance obligations was required for CSL Vifor to derive benefit from Vifor Agreement No. 2 for commercialization of the Licensed Product in the Territory. Therefore, thetwo performance obligations were not distinct from each other and were accounted for as a single performance obligation.

After U.S. regulatory approval of KORSUVA injection in August 2021, the Company achieved a $15,000 regulatory milestone payment and was recorded as license and milestone fees revenue for the year ended December 31, 2021, since this regulatory milestone payment was considered variable consideration at contract inception, was not included in the transaction price at the inception of the agreement and was allocated to theone performance obligation identified at contract inception (see Note 2,Summary of Significant Accounting Policies – Revenue Recognition).

In addition, after U.S. regulatory approval of KORSUVA injection in August 2021, the Company received an additional $50,000 in October 2021 for the purchase of an aggregate of 3,282,391 shares of the Company’s common stock at a price of $15.23 per share, which represented a 20% premium to the 30-day trailing average price of the Company’s common stock as of the date of the achievement of the milestone. The excess of the stock purchase price over the cost of the purchased shares at the closing price of the Company’s common stock on the date of the achievement of the milestone of $5,031 was allocated to theone performance obligation identified at contract inception and included as license and milestone fees revenue for the year ended December 31, 2021 (see Note 2,Summary of Significant Accounting Policies – Revenue Recognition).

As a result of the European Commission’s regulatory approval of Kapruvia in April 2022, the Company received a $15,000 regulatory milestone payment from CSL Vifor under Vifor Agreement No. 2, which was recorded as license and milestone fees revenue for the year ended December 31, 2022, since this regulatory milestone payment was considered variable consideration at contract inception, was not included in the transaction price at the inception of the agreement and was allocated to theone combined performance obligation identified at contract inception (see Note 2,Summary of Significant Accounting Policies – Revenue Recognition).

During the year ended December 31, 2023, the criteria for revenue recognition for a regulatory milestone event set forth in the Maruishi Agreement was achieved and the Company earned $1,449, of which $910 was recorded as license and milestone fees revenue based on the relative standalone selling prices described at contract inception. This regulatory milestone payment was considered variable consideration due to the uncertainty of occurrence of this event as specified at inception of the agreement. Therefore, this potential regulatory milestone payment was not included in the transaction price at the inception of the agreement. There wereno license and milestone fees revenue recognized under the Maruishi Agreement during the year ended December 31, 2022. During the year ended December 31, 2021, the criteria for revenue recognition for a milestone event set forth in the Maruishi Agreement was achieved, and the Company recorded $1,192 as license and milestone fees revenue based on the relative standalone selling prices described above at contract inception (see Note 2,Summary of Significant Accounting Policies – Revenue Recognition).

Royalty revenue

Royalty revenue includes amounts related to the Company’s royalties earned from CSL Vifor on the net sales of Kapruvia in Europe, based on the amount of net sales in a licensed territory during a calendar year. Sales-based royalty payments related to a license of IP are recognized as revenue when the respective sales occur, and the net sales tier is achieved. The Company recognized royalty revenue of approximately $415 and $72 for the years ended December 31, 2023 and 2022, respectively, which were related to the Company’s royalties on the net sales of Kapruvia in Europe prior to October 1, 2023. There wasno royalty revenue for the year ended December 31, 2021.

Beginning on October 1, 2023, royalty revenue will no longer be recognized until the Company has fulfilled its obligations under the HCR Agreement (see Note 10,Royalty Purchase and Sale Agreement).

Clinical compound revenue

The Company’s only performance obligation under the supply agreement with Maruishi is to deliver clinical compound to Maruishi in accordance with the receipt of purchase orders. During the years ended December 31, 2023 and 2021, the Company recognized clinical compound revenue of $165 and $37, respectively, from the sale of clinical compound to Maruishi. There wereno sales of clinical compound to Maruishi during the year ended December 31, 2022.

The Company’s only performance obligation under the Vifor Supply Agreement is to deliver compound to CSL Vifor in accordance with the receipt of purchase orders. There wereno sales of clinical compound under the Vifor Supply Agreement during the years ended December 31, 2023 and 2022. During the year ended December 31, 2021, the Company recognized clinical compound revenue of $361 from the sale of clinical compound to CSL Vifor.

Other revenue

The Company recorded other non-cash revenue of $699 which represents the royalty and milestone payments earned by the Company under Vifor Agreement No. 2 and the Maruishi Agreement during the fourth quarter of 2023 in conjunction with ex-U.S. sales of KORSUVA/Kapruvia, which will be remitted to HCR under the terms of the HCR Agreement. This non-cash revenue will continue to be recorded until the Company has fulfilled its obligations under the HCR Agreement (see Note 10,Royalty Purchase and Sale Agreement).

Contract balances

As of December 31, 2023 and 2022, the Company recorded accounts receivable, net – related party of $2,765 and $3,260 which primarily related to its profit-sharing revenue from sales of KORSUVA injection in the United States by CSL Vifor, its commercial supply of KORSUVA injection to CSL Vifor, and royalty payments from CSL Vifor. The Company also recorded other receivables of $415 which related to royalty payments from Maruishi. There wereno other

contract assets or contract liabilities related to the CSL Vifor, Maruishi and CKDP agreements as of December 31, 2023 and December 31, 2022.

The Company routinely assesses the creditworthiness of its license and collaboration partners. The Company has not experienced any losses related to receivables from its license and collaboration partners as of December 31, 2023 and December 31, 2022.

15. Stock-Based Compensation

2019 Inducement Plan

In October 2019, the Company’s Board of Directors adopted the 2019 Inducement Plan, or the 2019 Plan, which is a non-stockholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq Listing Rule 5635(c)(4), or Rule 5635, for the purpose of awarding (i) non-statutory stock options, (ii) restricted stock awards, (iii) restricted stock unit awards, (iv) other stock awards (collectively, the Inducement Awards) to new employees of the Company, as inducement material to such new employees entering into employment with the Company. In November 2019, the Company filed a Registration Statement on Form S-8 with the SEC covering the offering of up to 300,000 shares of its common stock, par value $0.001, pursuant to the Company’s 2019 Plan. No stock options were granted under the 2019 Plan during the years ended December 31, 2023, 2022 and 2021. Initial grants of Inducement Awards made to employees vest as to 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months and subsequent grants vest monthly over a period offour years from the grant date. As of December 31, 2023,300,000 shares remained available for grant pursuant to the Plan.

2014 Equity Incentive Plan

The Company’s 2014 Equity Incentive Plan, or the 2014 Plan, is administered by the Company’s Board of Directors or a duly authorized committee thereof, referred to as the Plan administrator. The 2014 Plan provides for the grant of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards, stock appreciation rights, performance stock awards and other forms of equity compensation, collectively referred to as Stock Awards. Additionally, the 2014 Plan provides for the grant of performance cash awards. Incentive stock options may be granted only to employees. All other awards may be granted to employees, including officers, non-employee directors, and consultants. No incentive stock options may be granted under the 2014 Plan after the tenth anniversary of the effective date of the 2014 Plan. Stock Awards granted under the 2014 Plan vest at the rate specified by the Plan administrator. Initial grants of Stock Awards made to employees and non-employee consultants generally vest as to 25% on the first anniversary of the date of grant and the balance ratably over the next 36 months and subsequent grants vest monthly over a period offour years from the grant date. Stock options initially granted to members of the Company’s Board of Directors vest over a period ofthree years in equal quarterly installments from the date of the grant, subject to the option holder’s continued service as a Director through such date. Subsequent grants to Directors that are made automatically at Annual Meetings of Stockholders vest fully on the earlier of the first anniversary of the date of grant and the next Annual Meeting of Stockholders. The Plan administrator determines the term of Stock Awards granted under the 2014 Plan up to a maximum often years.

The aggregate number of shares of the Company’s common stock reserved for issuance under the 2014 Plan has automatically increased on January 1 of each year, beginning on January 1, 2015 and will continue to increase on January 1 of each year through and including January 1, 2024, by 3% of the total number of shares of the Company’s capital stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares determined by the Company’s Board of Directors. On January 1, 2024, the aggregate number of shares of common stock that may be issued pursuant to Stock Awards under the 2014 Plan automatically increased from 12,203,023 to 13,837,444. The maximum number of shares that may be issued pursuant to the exercise of incentive stock options under the 2014 Plan is 30,000,000 shares.

Restricted Stock Units

Pursuant to the Company’s non-employee director compensation policy, an aggregate of 194,172 restricted stock units were granted to non-employee directors on June 1, 2023, the date of the Company’s 2023 Annual Meeting of Stockholders, under the 2014 Plan with a grant date fair value of $3.09 per share. The restricted stock units will vest on the earlier of (i) June 1, 2024 and (ii) immediately prior to the Company’s next Annual Meeting of Stockholders following the grant date, subject to the recipient’s continued service through such date. As a result, the Company recognizes compensation expense associated with these restricted stock units ratably over theone-year vesting period following the grant date. For the year ended December 31, 2023, stock compensation expense associated with these awards of $292 was recognized in general and administrative expense, or G&A expense. In November 2023,32,362 of these restricted stock units were forfeited as a result of the retirement of a member of the Company’s Board of Directors. As of December 31, 2023,161,810 restricted stock units were outstanding and available to vest and settle in shares of the Company’s common stock.

On March 1, 2023, the Compensation Committee of the Company’s Board of Directors, or the Compensation Committee, approved and granted a total of 407,000 restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $10.06 per share. Vesting of the restricted stock units is contingent on the achievement of certain performance targets, subject to the recipient’s continuous service through each performance target. Recognition of compensation expense associated with these awards begins when, and to the extent, the performance criteria are probable of achievement and the employee has met the service conditions. For the year ended December 31, 2023, no stock compensation expense relating to these restricted stock units was recognized. In December 2023,168,150 of these restricted stock units were forfeited as the performance targets associated with them were not achieved. As of December 31, 2023,238,850 restricted stock units were outstanding and available to vest and settle in shares of the Company’s common stock.

On October 12, 2022, the Compensation Committee of the Company’s Board of Directors, or the Compensation Committee, approved and granted a total of 7,267 time-based restricted stock units under the 2014 Plan, with a grant date fair value of $9.42 per share, to an executive officer of the Company. The restricted stock unit grant fully vests on August 31, 2023, subject to the recipient’s continued service through such date. For the years ended December 31, 2023 and 2022, the Company recognized $51 and $17, respectively, of stock compensation expense associated with these awards, all of which was recorded within G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units vested fully in August 2023.

On June 15, 2022, the Compensation Committee approved and granted a total of 7,500 time-based restricted stock units to the Company’s interim principal financial officer and principal accounting officer, as a result of his assuming the responsibilities of the Company’s former Chief Financial Officer, or CFO, on an interim basis, under the 2014 Plan with a grant date fair value of $7.94 per share. The Company accelerated the recognition of compensation expense and the restricted stock units vested fully on September 12, 2022, when the appointment of the Company’s new CFO occurred. For the year ended December 31, 2022, the Company recognized $60 of stock compensation expense associated with these awards, all of which was recorded within G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units vested fully in September 2022.

Pursuant to the Company’s non-employee director compensation policy, an aggregate of 59,380 restricted stock units were granted to non-employee directors on June 2, 2022, the date of the Company’s 2022 Annual Meeting of Stockholders, under the 2014 Plan with a grant date fair value of $8.42 per share. These restricted stock unit grants fully vested on June 2, 2023. As a result, the Company recognizes compensation expense associated with these restricted stock units ratably over theone-year vesting period following the grant date. For the years ended December 31, 2023 and 2022, stock compensation expense of $209 and $290, respectively, was recognized in G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units vested fully on June 2, 2023. Also in June 2022, the Company granted 11,876 fully vested restricted stock units, which were immediately settled in shares of common stock, to the Company’s chairman in consideration of his effort in connection with the Company’s CEO transition in 2021. For the year ended December 31, 2022, stock compensation expense of $100 was recognized in G&A expense associated with this award.

On February 25, 2022, the Compensation Committee also approved and granted a total of 243,000 restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $10.46 per share. Vesting of the restricted stock units was contingent on the achievement of certain performance targets related to commercial milestones, subject to the recipient’s continuous service through each performance target. Recognition of compensation expense associated with these awards began when, and to the extent, the performance criteria are probable of achievement and the employee has met the service conditions. For the year ended December 31, 2022, no stock compensation expense relating to these restricted stock units was recognized. In June 2022,29,000 of these restricted stock units were forfeited as a result of the resignation of the Company’s former CFO. In December 2022,214,000 of these restricted stock units were forfeited as the performance targets associated with them were not achieved. As of December 31, 2023, none of these restricted stock units were outstanding as they were forfeited in 2022.

Additionally on February 25, 2022, the Compensation Committee also approved and granted a total of 145,170 time-based restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $10.46 per share. The restricted stock units vest inthree equal installments annually from the date of the grant. As a result, the Company recognizes compensation expense associated with these restricted stock units ratably over thethree-year vesting period following the grant date. In April 2023,3,585 of these restricted stock units were forfeited. In February 2023,42,920 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the first year of vesting. In June 2022,20,000 of these restricted stock units were forfeited as a result of the resignation of the Company’s former CFO. For the years ended December 31, 2023 and 2022, the Company recognized $406 and $390, respectively, of stock compensation expense associated with these awards, with $135 recorded in R&D expense and $271 recorded in G&A expense for the 2023 period, and $161 recorded in R&D expense and $229 in G&A expense for the 2022 period. As of December 31, 2023,78,665 restricted stock units were outstanding and available to vest and settle in shares of the Company’s common stock.

On December 17, 2021, the Compensation Committee approved and granted a total of 63,573 time-based restricted stock units to certain executive officers under the 2014 Plan with a grant date fair value of $12.45 per share. The restricted stock units vested intwo equal installments on December 15, 2022 and June 15, 2023. As a result, the Company recognized compensation expense associated with these restricted stock units ratably over the 18-month vesting period following the grant date. On June 15, 2023,26,199 of these restricted stock units fully vested and were settled in shares of the Company’s common stock. In December 2022, an aggregate of 26,204 of these restricted stock units vested and were settled in shares of the Company’s common stock. In June 2022,11,170 of these restricted stock units were forfeited as a result of the resignation of the Company’s former CFO. For the years ended December 31, 2023, 2022 and 2021, the Company recognized $199, $433 and $20, respectively, of stock compensation expense, with $96 recorded in R&D expense and $103 recorded in G&A expense for the 2023 period, $210 recorded in R&D expense and $223 recorded in G&A expense for the 2022 period, and $8 recorded in R&D expense and $12 in G&A expense for the 2021 period. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units fully vested in June 2023.

On October 29, 2021, the Compensation Committee also approved and granted 147,942 time-based restricted stock units in connection with the appointment of the Company’s new Chief Executive Officer, or CEO, under the 2014 Plan with a grant date fair value of $16.83 per share. The first tranche of 142,000 restricted stock units vested 25% on the first anniversary of the date of grant and the balance vests quarterly over the next 36 months. The Company recognizes compensation expense associated with thesetwo restricted stock unit tranches ratably over their respective vesting periods following the grant date. During the year ended December 31, 2023,35,500 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the quarterly periods of vesting. In addition,35,500 of these restricted stock units vested and were settled in shares of the Company’s common stock in October 2022. The second tranche of 5,942 restricted stock units fully vested on March 31, 2022. For the years ended December 31, 2023, 2022 and 2021, stock compensation expense of $598, $657 and $144 respectively, was recognized in G&A expense. As of December 31, 2023,71,000 restricted stock units were outstanding and available to vest and settle in shares of the Company’s common stock.

Pursuant to the Company’s non-employee director compensation policy, an aggregate of 43,200 restricted stock units were granted to non-employee directors on June 3, 2021, the date of the Company’s 2021 Annual Meeting of Stockholders, under the 2014 Plan with a grant date fair value of $13.06 per share. The restricted stock units vested on June 3, 2022. As a result, the Company recognized compensation expense associated with these restricted stock units ratably over theone-year vesting period following the grant date. For the years ended December 31, 2022 and 2021, stock compensation expense of $238 and $326 respectively, was recognized in G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these were fully vested in June 2022.

On March 30, 2021, the Compensation Committee approved and granted a total of 176,000 restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $20.59 per share. Vesting of the restricted stock units was contingent on the achievement of certain performance targets related to clinical and regulatory milestones, subject to the recipient’s continuous service through each performance target. Recognition of compensation expense associated with these awards begins when, and to the extent, the performance criteria was probable of achievement and the employee had met the service conditions. In March 2022,93,999 restricted stock units were forfeited as a result of not achieving certain defined performance targets of the awards. In February 2022 and August 2021, performance targets relating to 37,999 and 44,002 restricted stock units, respectively, had been achieved and thus restricted stock units vested and the awards were settled in shares of common stock. For the year ended December 31, 2022, the Company recognized $729 of stock compensation expense associated with these awards in G&A expense. G&A amounts recorded for the year ended December 31, 2022 included $303 of stock compensation expense relating to the modification of certain of these restricted stock units on November 1, 2021 (seeStock Award Modifications below). For the year ended December 31, 2021, the Company recognized $906 of stock compensation expense, with $329 recorded in R&D expense and $577 recorded in G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units were either fully vested or forfeited in prior periods.

Additionally on March 30, 2021, the Compensation Committee also approved and granted a total of 100,000 time-based restricted stock units to certain executive officers under the 2014 Plan with a grant date fair value of $20.59 per share. The restricted stock units vest inthree equal installments annually from the date of the grant. As a result, the Company recognizes compensation expense associated with these restricted stock units ratably over thethree-year vesting period following the grant date. In March 2023,15,999 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the second year of vesting. In June 2022,17,333 of these restricted stock units vested and were settled in shares of the Company’s common stock in accordance with the acceleration of vesting provisions relating to the modification of certain of these restricted stock units on November 1, 2021. Also in June 2022,17,333 restricted stock units were forfeited as a result of the completion of the consulting agreement in relation to the modification of certain of these restricted stock units on November 1, 2021 (see* Stock Award Modifications* below). In March 2022,33,336 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the first year of vesting. For the years ended December 31, 2023, 2022 and

2021, the Company recognized $329, $646 and $592, respectively, of stock compensation expense associated with these awards, with $219 recorded in R&D expense and $110 in G&A expense for the 2023 period, $219 recorded in R&D expense and $427 in G&A expense for the 2022 period, and $166 recorded in R&D expense and $426 in G&A expense for the 2021 period. G&A amounts recorded for the years ended December 31, 2022 and 2021 included $317 and $75, respectively, of stock compensation expense relating to the modification of certain of these restricted stock units on November 1, 2021 (seeStock Award Modifications below). As of December 31, 2023,15,999 restricted stock units were outstanding and available to vest and settle in shares of the Company’s common stock.

Pursuant to the Company’s non-employee director compensation policy, an aggregate of 36,000 restricted stock units were granted to non-employee directors on June 4, 2020, the date of the Company’s 2020 Annual Meeting of Stockholders, under the 2014 Plan with a grant date fair value of $15.62 per share. The restricted stock units fully vested on June 3, 2021. As a result, the Company recognized compensation expense associated with these restricted stock units ratably over theone-year vesting period following the grant date. For the year ended December 31, 2021, $239 of stock compensation expense relating to these restricted stock units was recognized in G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units were fully vested in June 2021.

In February 2020, the Compensation Committee approved and granted a total of 138,000 restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $16.36 per share. Vesting of the restricted stock units was contingent on the achievement of certain performance targets related to clinical and regulatory milestones, subject to the recipient’s continuous service through each performance target. Recognition of compensation expense associated with these awards begins when, and to the extent, the performance criteria is probable of achievement and the employee has met the service conditions. During the year ended December 31, 2022,24,500 of these restricted stock units were forfeited as a result of not achieving certain defined performance targets of the awards. In February and March 2021, performance targets relating to 36,750 and 40,000 restricted stock units, respectively, had been achieved and thus restricted stock units vested and the awards were settled in shares of common stock. For the year ended December 31, 2021, the Company recognized $1,256 of stock compensation expense relating to the vesting of these restricted stock units, with $524 recorded in R&D expense and $732 in G&A expense. As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units were either fully vested or forfeited in prior periods.

Additionally in February 2020, the Compensation Committee also approved and granted a total of 98,000 time-based restricted stock units to certain employees under the 2014 Plan with a grant date fair value of $16.36 per share. The restricted stock units vested inthree equal installments annually from the date of the grant. As a result, the Company recognized compensation expense associated with these restricted stock units ratably over thethree-year vesting period following the grant date. In February 2023,15,999 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the third year of vesting. In June 2022,16,666 of these restricted stock units vested and were settled in shares of the Company’s common stock in accordance with the acceleration of vesting provisions relating to the modification of certain of these restricted stock units on November 1, 2021 (see* Stock Award Modifications* below). In February 2022,32,666 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the second year of vesting. In February 2021,32,669 of these restricted stock units vested and were settled in shares of the Company’s common stock in satisfaction of the first year of vesting. For the years ended December 31, 2023, 2022 and 2021, the Company recognized $39, $526 and $607 of stock compensation expense associated with these awards, with $26 recorded in R&D expense and $13 in G&A expense for the 2023 period, $175 recorded in R&D expense and $351 in G&A expense for the 2022 period, and $174 recorded in R&D expense and $433 recorded in G&A expense for the 2021 period. G&A amounts recorded for the years ended December 31, 2022 and 2021 included $264 and $73, respectively, of stock compensation expense relating to the modification of certain of these restricted stock units on November 1, 2021 (see* Stock Award Modifications* below). As of December 31, 2023, none of these restricted stock units were outstanding as these restricted stock units were fully vested in February 2023.

A summary of restricted stock unit activity related to employees and non-employee members of the Company’s Board of Directors as of and for the year ended December 31, 2023 is as follows:

Stock Options

A summary of the Company’s stock option activity related to employees, non-employee members of the Board of Directors and non-employee consultants for the 2019 Plan and the 2014 Plan as of and for the year ended December 31, 2023 is as follows:

The total fair value of options vested during the years ended December 31, 2023, 2022 and 2021 was $12,810, $14,156, and $12,844, respectively. The intrinsic value of options exercised during the years ended December 31, 2023, 2022 and 2021 was $476, $118, and $965, respectively.

During the years ended December 31, 2023, 2022 and 2021, the Company granted 2,004,668,1,899,919 and 1,422,750 stock options, respectively, to employees and non-employee members of the Board of Directors. There wereno options granted to nonemployee consultants during the years ended December 31, 2023, 2022 and 2021. The fair values of the stock options granted to those groups were estimated using the Black-Scholes option valuation model with

the following ranges of assumptions (see Note 2,Summary of Significant Accounting Policies – Stock-Based Compensation):

The weighted average grant date fair value of options granted to employees and non-employee members of the Board of Directors for their Board service during the years ended December 31, 2023, 2022 and 2021 was $5.75, $7.25, and $12.00, respectively.

During the years ended December 31, 2023, 2022 and 2021, the Company recognized compensation expense relating to stock options as follows:

The following were excluded from the table above as they are not related to stock options: compensation expense for i) the vesting of certain employees’ restricted stock units for $476, $765 and $1,201 in R&D expense for the years ended December 31, 2023, 2022 and 2021, respectively, and $1,146, $2,693 and $2,324 in G&A expense for the years ended December 31, 2023, 2022 and 2021, respectively; and ii) compensation expense relating to the Board of Directors’ restricted stock units for $501, $628 and $565 in G&A expense for the years ended December 31, 2023, 2022 and 2021, respectively.

As of December 31, 2023, the total compensation expense relating to unvested options granted to employees and non-employee members of the Board of Directors that had not yet been recognized was $20,263, which is expected to be realized over a weighted average period of 2.33 years. The Company will issue shares upon exercise of options from common stock reserved.

The Company does not expect to realize any tax benefits from its stock option activity or the recognition of stock-based compensation expense because the Company currently has net operating losses and has a full valuation allowance against its deferred tax assets. Accordingly, no amounts related to excess tax benefits have been reported in cash flows from operations for the years ended December 31, 2023, 2022 and 2021.

Stock Award Modifications

In November 2021, the Company and the former President and CEO mutually agreed to a transition from CEO to a consulting role through June 30, 2022, if not terminated earlier per the terms of the consulting agreement. As a result, the Company modified the terms of its former CEO’s outstanding Stock Awards to (1) automatically vest any unvested stock options or time-based restricted stock units that would have vested in thetwelve month period following the end of the consulting period if continuous service is achieved with the Company during such twelve-month period; (2) extend the period during which the vested stock options may be exercised through the earlier of (i)eighteen months following

the separation date (November 8, 2021); or (ii) the original expiration date applicable to each of the stock options, unless terminated earlier in accordance with the 2014 Plan, if continuous service is achieved with the Company; and (3) extend the period in which performance-based vesting milestones for restricted stock units may be achieved through March 31, 2022, if continuous service is achieved with the Company. The consulting agreement ended on June 30, 2022.

The Company determined that vested Stock Awards which had modifications due to the extension of the exercise period were Type 1 modifications pursuant to ASC 718 because those Stock Awards would have vested before and after the modification. Acceleration of vesting for the Stock Awards that would have vested in thetwelve-month period following the consulting term was determined to be a Type 3 modification requiring stock compensation expense pursuant to ASC 718 because absent the modification terms, those Stock Awards would have been forfeited as of the last day that the former CEO provided continuous service as a consultant. In addition, Type 4 performance-based restricted stock units were not considered probable of achieving performance targets on the modification date, but the vesting targets were achieved with respect to 17,333 performance-based restricted stock units in February 2022, which resulted in additional stock compensation expense being recorded through June 30, 2022.

During the year ended December 31, 2022, total incremental stock compensation expense relating to modifications of stock options, time-based and performance-based restricted stock units of the former CEO was $2,563, which was included in G&A expense. Of this total amount, $1,679 was included in G&A expense in the stock option expense table above for the year ended December 31, 2022. During the year ended December 31, 2021, total incremental stock compensation expense relating to modifications of stock options and time-based restricted stock units of the former CEO was $5,056, which was included in G&A expense. Of that total amount, $4,908 is included in G&A expense in the stock option compensation expense table above for the year ended December 31, 2021.

16. Income Taxes

The Company’s benefit from income taxes is as follows:

Historically, the Company’s benefit from income taxes related to state R&D tax credits exchanged for cash. The State of Connecticut provides companies with the opportunity to exchange certain R&D credit carryforwards for cash in exchange for foregoing the carryforward of the R&D credit. The program provides for such exchange of the R&D credits at a rate of 65% of the annual R&D credit, as defined. The Company opted not to exchange its R&D tax credit for the year ended December 31, 2023, and the Company was not eligible to exchange its R&D tax credit for cash during the years ended December 31, 2022 and 2021, therefore there wasno benefit from income taxes for the years ended December 31, 2023, 2022 and 2021. As of December 31, 2023, the Company recorded $697 within income tax receivable which related to the 2020 R&D credit.

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations is as follows:

Significant components of the Company’s deferred tax assets and liabilities are as follows:

A 100% valuation allowance has been recorded on the deferred tax asset as of December 31, 2023 and 2022 because management believes it is more likely than not that the asset will not be realized. The change in the valuation allowance during 2023 and 2022 was an increase of $31,977 and $17,426, respectively.

The consolidated financial statements reflect expected future tax consequences of such positions presuming the taxing authorities possess full knowledge of the position and all relevant facts. As of December 31, 2023 and 2022, the Company hadno unrecognized tax benefits or related interest and penalties accrued. In the event the Company determines that accrual of interest or penalties are necessary in the future, the amount will be presented as a component of income tax expense.

At December 31, 2023, the Company had federal and state net operating loss, or NOL, carryforwards of $467,005 and $473,265, respectively. The federal and state tax loss carryforwards will begin to expire in 2026 and 2027, respectively, unless previously utilized. The federal NOLs arising in 2018 and forward have an unlimited carryforward period and losses from 2018-2020 may be carried back five years due to the Coronavirus Aid, Relief, and Economic Security Act of 2020, or the CARES Act. The Company conducted a 382 analysis in the first quarter of 2021. This analysis showed a limited change of ownership had occurred, and thus the full amount of the Company’s NOL carryforwards and R&D tax credits could be utilized annually in the future to offset taxable income or tax, respectively. The Company also had federal and state R&D tax credit carryforwards of $27,488 and $4,495, respectively. The federal credits will begin expiring in 2025 unless previously utilized. The Connecticut credit carryforwards have no expiration period. Because of the NOL and research credit carryforwards, tax years 2006 through 2023 remain open to U.S. federal and state tax examinations.

Further, beginning in the Company’s tax year ending December 31, 2022, as a result of the Tax Cuts and Jobs Act of 2017, current R&D expenditures incurred in the United States must be capitalized for tax purposes, and amortized over a period of five years (fifteen years in the case of R&D performed outside the United States).

In March 2020, former President Trump signed into law the CARES Act (H.R. 748), which was further expanded with the signing of the Consolidation Appropriations Act of 2021 (H.R. 133) on December 27, 2020. The CARES Act (and December expansion) includes a variety of economic and tax relief measures intended to stimulate the economy, including loans for small businesses, payroll tax credits/deferrals, and corporate income tax relief. Due to the Company’s history of tax loss carryforwards and full valuation allowance, the CARES Act did not have a significant effect on the income tax provision, as the corporate income tax relief was directed towards cash taxpayers.

17. Net Loss per Share

The denominators used in the net loss per share computations are as follows:

Basic and diluted net loss per share is computed as follows:

As of December 31, 2023,7,897,647 stock options and 566,324 restricted stock units were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive as a result of the net loss for the period.

As of December 31, 2022,7,689,449 stock options and 372,513 restricted stock units were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive as a result of the net loss for the period.

As of December 31, 2021,6,512,280 stock options and 576,544 restricted stock units were outstanding, which could potentially dilute basic earnings per share in the future, but were not included in the computation of diluted net loss per share because to do so would have been anti-dilutive as a result of the net loss for the period.

18. Employee Benefit Plan

The Company’s defined contribution retirement plan complies with Section 401(k) of the Internal Revenue Code. All employees over the age of 21 are eligible to participate in the plan on the first day of the month after completing three consecutive months of service. Employees are able to defer a portion of their pay into the plan on the first day of the month on or after the day all age and service requirements have been met. All eligible employees receive an employer contribution equal to 3% of their salary up to the annual IRS limit. During the years ended December 31, 2023, 2022 and 2021, employer contributions to the plan were$643,$505, and$460, respectively.

19. Commitments and Contingencies

License Agreement with Enteris Biopharma, Inc.

In August 2019, the Company entered into a non-exclusive license agreement, or the Enteris License Agreement, with Enteris Biopharma, Inc., or Enteris, pursuant to which Enteris granted to the Company a non-exclusive, royalty-bearing license, including the right to grant sublicenses, under certain proprietary technology and patent rights related to or covering formulations for oral delivery of peptide active pharmaceutical ingredients with functional excipients to enhance permeability and/or solubility, known as Enteris’s Peptelligence® technology, to develop, manufacture and commercialize products using such technology worldwide, excluding Japan and South Korea.

As consideration for the licensed rights under the Enteris License Agreement, the Company paid an upfront fee equal to$8,000, consisting of$4,000 in cash and$4,000 in shares of the Company’s common stock pursuant to the Purchase Agreement with Enteris.

The Company is also obligated, pursuant to the Enteris License Agreement, to pay Enteris (1) milestone payments upon the achievement of certain development, regulatory and commercial milestones and (2) low-single digit royalty percentages on net sales of licensed products, subject to reductions in specified circumstances. During the year ended

December 31, 2023, no milestone payments or royalties were paid to Enteris by the Company in relation to the Enteris License Agreement. During the years ended December 31, 2022 and 2021, the Company paid$5,000 and$15,000, respectively, to Enteris for milestones earned in relation to the Enteris License Agreement and as a result, the Company recognized$5,000 and$15,000 of R&D expense related to the Enteris License Agreement during these respective years.

The Enteris License Agreement will expire on a country-by-country, licensed product-by-licensed product basis upon the later of (1) the expiration (or invalidation) of all valid claims in licensed patent rights that cover such product in such country, (2) the end of the calendar quarter in which generic competition (as defined in the Enteris License Agreement) occurs for such product in such country and (3)ten years from the first commercial sale of such product.

Either party may terminate the Enteris License Agreement upon written notice if the other party has failed to remedy a material breach within 60 days (or 30 days in the case of a material breach of a payment obligation). Enteris may terminate the Enteris License Agreement upon 30 days’ written notice to the Company if the Company or any of its affiliates formally challenge the validity of any licensed patent rights or assists a third party in doing so. The Company may terminate the Enteris License Agreement for any reason or no reason (a) prior to receipt of first regulatory approval for a licensed product in the United States for any indication upon 30 days’ prior written notice to Enteris or (b) on or after receipt of first regulatory approval for a licensed product in the United States for any indication upon 60 days’ prior written notice to Enteris.

Manufacturing Agreements

In July 2021, the Company entered into an API Commercial Supply Agreement with Polypeptide Laboratories S.A., or PPL, that defines each party’s responsibilities with respect to PPL’s manufacture and supply of the API difelikefalin, for the difelikefalin injection product candidate. Under the API Commercial Supply Agreement, PPL shall manufacture API at its facility for sale and supply to the Company, in the amounts as set forth in purchase orders to be provided by the Company. The Company will be required to purchase its requirements of API for each year of the term of the agreement, based on internal forecasts.

The API Commercial Supply Agreement will continue until the fifth anniversary of the approval by the FDA of the new drug application for KORSUVA injection, unless the API Commercial Supply Agreement is earlier terminated, and will automatically be extended for successive five-year periods unless either party gives notice to the other party of its intention to terminate.

In July 2019, the Company entered into a Master Manufacturing Services Agreement, or MSA, with Patheon UK Limited, or Patheon. The MSA governs the general terms under which Patheon, or one of its affiliates, will provide non-exclusive manufacturing services to the Company for the drug products specified by the Company from time to time. Pursuant to the MSA, the Company has agreed to order from Patheon at least a certain percentage of its commercial requirements for a product under a related Product Agreement. Each Product Agreement that the Company may enter into from time to time will be governed by the terms of the MSA, unless expressly modified in such Product Agreement.

The MSA has an initial term ending December 31, 2024, and will automatically renew after the initial term for successive terms oftwo years each if there is a Product Agreement in effect, unless either party gives notice of its intention to terminate the MSA at least 18 months prior to the end of the then current term.

Either party may terminate the MSA or a Product Agreement upon written notice if the other party (1) has failed to remedy a material breach within a specified time or (2) is declared insolvent or bankrupt, voluntarily files a petition of bankruptcy or assigns such agreement for the benefit of creditors. The Company may terminate a Product Agreement (a) upon 90 days’ prior written notice if any governmental agency takes any action that prevents the Company from selling the relevant product in the relevant territory, (b) uponsix months’ prior written notice if it does not intend to

order manufacturing services due to a product’s discontinuance in the market, or (c) upon 90 days’ prior written notice if it determines that the manufacture or supply of a product likely infringes third-party rights. Patheon may terminate the MSA or a Product Agreement (i) uponsix months’ prior written notice if the Company assigns such agreement to an assignee that is unacceptable to Patheon for certain reasons, or (ii) upon 30 days’ prior written notice if, after the first year of commercial sales, the Company forecasts zero volume for 12 months.

The MSA contains, among other provisions, customary representations and warranties by the parties, a grant to Patheon of certain limited license rights to the Company’s intellectual property in connection with Patheon’s performance of the services under the MSA, certain indemnification rights in favor of both parties, limitations of liability and customary confidentiality provisions.

Also in July 2019, the Company entered intotwo related Product Agreements under the MSA, one with each of Patheon and Patheon Manufacturing Services LLC, or Patheon Greenville, to govern the terms and conditions of the manufacture of commercial supplies of difelikefalin injection, the Company’s lead product candidate. Pursuant to the Product Agreements, Patheon and Patheon Greenville will manufacture commercial supplies of difelikefalin injection at the Monza, Italy and Greenville, North Carolina manufacturing sites, respectively, from API supplied by the Company. Patheon and Patheon Greenville will be responsible for supplying the other required raw materials and packaging components, and will also provide supportive manufacturing services such as quality control testing for raw materials, packaging components, and finished product.

In December 2023, the Company entered into an agreement with Patheon to reimburse Patheon approximately $1,700 for forecasted manufacturing commitments that are no longer needed due to the reduced demand expectations of KORSUVA in the United States and was recorded within accounts payable and accrued expenses on its Consolidated Balance Sheet. In connection with the agreement with Patheon, the Company agreed to schedule additional manufacturing commitments in 2024.

Lease (New Corporate Headquarters in May 2023)

On May 11, 2023, the Company entered into the New Lease for the Company’s new principal executive offices. The initial term of the New Lease commences on the earlier to occur of (a) the date the Company first occupies the premises for the regular conduct of its business therein, and (b) the date the Landlord delivers the premises to the Company in the condition required under the terms of the New Lease, provided that such date shall be no sooner than November 1, 2023, or the Commencement Date, and will expire on the last day of the calendar month in which occurs the tenth anniversary of the Rent Commencement Date, as defined below, or the Term.

In connection with the signing of the New Lease, the Company entered into a standby letter of credit agreement for $1,500 which serves as a security deposit for the leased office space. This standby letter of credit is secured with restricted cash in a money market account and is included within long-term assets as of December 31, 2023 (refer to Note 8,* Restricted Cash*).

The annual fixed rent rate under the New Lease will initially be $1,300 (considered by the Company to be at market rate as of the signing of the New Lease), commencing on the date which is the later to occur of (a) the date which is 12 months after the Commencement Date and (b) November 1, 2024, or the Rent Commencement Date, and will increase 2.5% annually thereafter. The Company expects to begin paying rent in November 2024.

The Company is also responsible for the payment of Additional Rent, as defined in the New Lease, including its share of the operating and tax expenses for the building. As a result, the New Lease contains both a lease (the right to use the asset) and a non-lease component (common area maintenance services) which are accounted for separately. The Company allocates the consideration to the lease and non-lease component on a relative standalone price basis.

The Company will have theoption to extend the Term under the New Lease for an additional five years on the same terms and conditions (other than with respect to the annual fixed rent at the annual fair market rental rate, as defined in the New Lease) as set forth in the New Lease. This renewable term is not included as part of the lease term as defined in ASC 842 since it is not reasonably certain that the Company will exercise that option on the Commencement Date.

On July 28, 2023, the Company recorded a lease liability and a ROU asset for the New Lease since it obtained control of the premises to begin work on its leasehold improvements prior to the Commencement Date. The initial lease liability of $6,672 was recorded as the sum of the present value of the future minimum lease payments over the term of the lease. Lease incentives of $2,900 were not included within lease payments since the timing of these costs being incurred and reimbursed to the Company was uncertain, and they are neither paid nor payable as of July 28, 2023. These lease incentives will reduce the lease liability and ROU asset by the costs incurred once the Company actually incurs the costs and the amounts qualify for reimbursement. The reduction to the lease liability will be reversed once the Company is reimbursed for the qualified costs. The reduction to the ROU asset will be recognized prospectively over the remainder of the lease term. The ROU asset of $6,779 was initially recorded as the amount of the lease liability plus prepaid rent paid in May 2023. In October and November 2023, the Company incurred $1,755 of costs that qualified for reimbursement as lease incentives, of which $808 had been reimbursed to the Company as of December 31, 2023.

Beginning on July 28, 2023 and during the entire term of the New Lease, interest expense is calculated using the effective interest method and the ROU asset (including prepaid rent) will be amortized on a straight-line basis over the lease term, and both will be recorded as lease expense. As a result, lease expense of $524 for the New Lease was recorded for the year ended December 31, 2023, consisting of $367 relating to R&D lease expense and $157 relating to G&A lease expense.

Leases (Original Corporate Headquarters in 2015 & Amendment for Additional Space in 2020)

The Company’s original Stamford Lease and Lease Amendment for prior office space both terminated in December 2023. Lease expense for the Stamford Lease and Lease Amendment was recognized on a straight-line basis over the lease term of the Company’s prior lease agreements in Stamford, Connecticut. As a result, $1,624 of operating lease cost, or lease expense, was recognized for each of the years ended December 31, 2023, 2022 and 2021, respectively, consisting of $1,137 relating to R&D lease expense and $487 relating to G&A lease expense in each respective period.

Other information related to the leases (both new in May 2023 and terminated in December 2023) was as follows:

Future minimum lease payments under the non-cancellable operating lease for the New Lease, as well as a reconciliation of these undiscounted cash flows to the operating lease liability as of December 31, 2023, were as follows:

20. Legal Matters

From time to time, the Company may become subject to arbitration, litigation or claims arising in the ordinary course of its business. The Company is not currently a party to any arbitration or legal proceeding that, if determined adversely to the Company, would have a material adverse effect on its business, operating results or financial condition. The results of any future claims or proceedings cannot be predicted with certainty, and regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors.

21. Related Party Transactions

As of December 31, 2023, Vifor International owned 7,396,770, or 13.6%, of the Company’s common stock. CSL Vifor and its affiliates are considered related parties as of December 31, 2023, 2022 and 2021(see Note 13,Collaboration and Licensing Agreements).

As of December 31, 2023 and 2022, amounts due from CSL Vifor of$2,765 and$3,260, respectively, primarily relating to the Company’s share of the profit generated by sales of KORSUVA injection in the United States by CSL Vifor, its commercial supply of KORSUVA injection to CSL Vifor, and royalty payments from CSL Vifor were included within accounts receivable, net – related party.

The Company’s collaborative revenue of$12,397 and$16,572 from its share of the profit generated by sales of KORSUVA injection in the United States by CSL Vifor was included within collaborative revenue for the years ended December 31, 2023 and 2022, respectively.

Sales of KORSUVA injection to CSL Vifor of$5,843,$10,223 and$701 were included within commercial supply revenue for the years ended December 31, 2023, 2022 and 2021, respectively. The associated COGS for the Company’s commercial supply revenue from CSL Vifor was$6,174,$7,266, and$0 for the years ended December 31, 2023, 2022 and 2021, respectively.

The Company recorded$15,000 as license and milestone fees revenue from Vifor Fresenius Medical Care Renal Pharma Ltd. for the year ended December 31, 2022, as a result of the European Commission’s regulatory approval of KORSUVA in April 2022. During the year ended December 31, 2021, the Company recorded as license and milestone fees revenue: i)$15,000 as license and milestone fees revenue from Vifor Fresenius Medical Care Renal Pharma Ltd. for the approval of KORSUVA injection in August 2021, and ii)$5,031 of premium from Vifor International’s purchase of the Company’s common stock.

The Company recorded $415 and $72 as royalty revenue based on net sales of Kapruvia outside of the United States during the years ended December 31, 2023 and 2022, respectively.

Sales of clinical compound to CSL Vifor for $361 were included within clinical compound revenue for the year ended December 31, 2021.

The Company recorded $284 as other revenue from its royalty payments from CSL Vifor for the year ended December 31, 2023.

22. Subsequent Event

On January 22, 2024, the Company announced a planned workforce reduction of up to 50% of its employees in order to reduce its operating expenses and focus its efforts on development of oral difelikefalin in chronic pruritus associated with notalgia paresthetica. The Company expects to record a pre-tax severance expense of approximately $2,700 during the first quarter of 2024. As a result of these workforce reductions, approximately 703,000 stock options and 46,000 restricted stock units, as of December 31, 2023, are expected to be forfeited (see Note 15,Stock-Based Compensation).