Milestone Pharmaceuticals Inc.

1. Organization and Nature of Operations

Milestone Pharmaceuticals Inc., or “Milestone,” or the “Company,” is a biopharmaceutical company incorporated under theBusiness Corporations Act (Québec). Milestone’s headquarters is currently located in Montréal (Québec), Canada. The Company’s common shares began trading on The Nasdaq Global Select Market on May 9, 2019, and trade under the symbol “MIST”. Milestone is focused on the development and commercialization of innovative cardiovascular medicines. Milestone’s lead product candidate, etripamil, is a novel, potent rapid-onset calcium channel blocker that the Company designed and is developing as a rapid-onset nasal spray to be administered by patients. On December 12, 2025, CARDAMYST™ (etripamil) was approved by the U.S. Food and Drug Administration, or “FDA,” to treat paroxysmal supraventricular tachycardia, or “PSVT.” The Company is also developing etripamil for the treatment of atrial fibrillation with rapid ventricular rate, or “AFib-RVR,” and other cardiovascular indications.

2. Summary of Significant Accounting Policies

a) Basis of Consolidation

The condensed consolidated financial statements include the accounts of the Company and Milestone Pharmaceuticals USA, Inc. All intercompany transactions and balances have been eliminated.

b) Basis of Presentation and Use of Accounting Estimates and Significant Accounting Policies

These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America, or “U.S. GAAP,” pursuant to the rules and regulations of the Securities and Exchange Commission (SEC) for interim financial information, and on a basis consistent with those accounting principles followed by the Company and disclosed in Note 2, “Summary of Significant Accounting Policies,” of its most recent annual consolidated financial statements. Certain information, in particular the accompanying notes normally included in the annual financial statements prepared in accordance with U.S. GAAP, has been omitted or condensed. Accordingly, these unaudited interim condensed consolidated financial statements do not include all the information required for full annual financial statements, and therefore, should be read in conjunction with the annual consolidated financial statements and the notes thereto for the year ended December 31, 2025.

In the opinion of the Company's management, the accompanying unaudited interim condensed consolidated financial statements contain all adjustments, consisting of only normal recurring adjustments, necessary for a fair statement of its condensed consolidated balance sheet as of March 31, 2026, and its condensed consolidated statements of loss and shareholders’ equity for the three-months ended March 31, 2026 and 2025, and its condensed consolidated statements of cash flows for the three-months ended March 31, 2026 and 2025.

The condensed consolidated balance sheet as of December 31, 2025, was derived from the audited annual consolidated financial statements, but does not contain all the footnote disclosures required by U.S. GAAP. Commencing in the three months ended March 31, 2026, amounts previously presented as “Accounts payable and accrued liabilities” on the Condensed Consolidated Balance Sheets are presented separately as “Accounts payable” and “Accrued liabilities.” Comparative amounts have been reclassified to conform with the current period presentation.

These unaudited interim condensed consolidated financial statements are presented in US dollars, which is the Company’s functional currency.

The preparation of unaudited interim condensed consolidated financial statements in conformity with U.S. GAAP requires the Company to make estimates and judgments that affect certain reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the period. The Company bases its estimates and assumptions on current facts, historical experience

and various other factors that it believes are reasonable under the circumstances, to determine the carrying values of assets and liabilities that are not readily apparent from other sources. Significant estimates and judgments include, but are not limited to,

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 condensed 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. These estimates 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 from those estimates, and any such differences may be material to the Company’s condensed consolidated financial statements.

c) Significant Risks and Uncertainties

The Company is subject to challenges and risks specific to its business and its ability to execute on its strategy, as well as risks and uncertainties common to companies in the pharmaceutical industry, including, without limitation, risks and uncertainties associated with: commercializing CARDAMYST; procuring inventory given the Company’s reliance on a concentrated supplier base, delays or problems in the supply of its study drug or failure to comply with manufacturing regulations; identifying, acquiring or in-licensing product candidates; pharmaceutical product development and the inherent uncertainty of clinical success; and the challenges of protecting and enhancing its intellectual property rights; and complying with applicable regulatory requirements.

Further, the Company may be impacted by general economic, political, and market conditions, including deteriorating market conditions due to investor concerns regarding inflation, armed conflicts, and overall fluctuations in the financial markets in the U.S. and abroad.

d) Recent Accounting Pronouncements

In November 2024, the Financial Accounting Standards Board, or “FASB,” issued Accounting Standards Update, or “ASU” 2024-03 “Income Statement: Reporting Comprehensive Income— Expense Disaggregation Disclosures,” which requires more detailed information about specified categories of expenses (purchases of inventory, employee compensation, depreciation, amortization, and depletion) included in certain expense captions presented on the face of the income statement, as well as disclosures about selling expenses. This ASU is effective for fiscal years beginning after December 15, 2026, and for interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. The amendments may be applied either (1) prospectively to financial statements issued for reporting periods

after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating this guidance to determine the impact it may have on its financial statement disclosures.

In November 2024, the FASB issued ASU 2024-04,“Debt—Debt with Conversion and Other Options (Subtopic 470-20): Induced Conversions of Convertible Debt Instruments,” which clarifies the requirements for determining whether certain settlements of convertible debt instruments should be accounted for as induced conversions or as debt extinguishments. This ASU is effective for fiscal years beginning after December 15, 2025, including interim periods within those fiscal years. The amendments may be applied on either a prospective or retrospective basis. The Company adopted this standard and determined that it did not have a material impact with respect to the condensed consolidated financial statements.

In July 2025, the FASB issued ASU 2025-05,“Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses for Accounts Receivable and Contract Assets,” which provides a practical expedient for estimating expected credit losses on current accounts receivable and current contract assets arising from transactions accounted for under ASC 606. This ASU is effective for fiscal years beginning after December 15, 2025, including interim periods within those fiscal years. The amendments are applied prospectively. The Company adopted this standard and determined that it did not have a material impact with respect to the condensed consolidated financial statements.

e) Sources of Liquidity and Funding Requirements

The Company has incurred operating losses and experienced negative operating cash flows since its inception and expects to incur additional costs in connection with commercialization. To date the Company has, and intends to continue, financing commercialization and working capital needs from existing cash, proceeds from the commercialization of CARDAMYST, royalty revenue, the exercise of outstanding common stock options and warrants to purchase common stock, and existing and future licensing and commercial partnership agreements. As of March 31, 2026, the Company had cash, cash equivalents and short-term investments of $184.2 million and an accumulated deficit of $456.7 million. The Company believes that its cash, cash equivalents and short-term investments as of March 31, 2026, will be sufficient to allow the Company to fund its planned operations for at least the next 12 months from the date of these unaudited interim condensed consolidated financial statements.

The Company has historically financed its operations primarily through the sale of equity securities, convertible notes, short-term investments, and from cash received pursuant to its license agreement. Although the Company is now generating product revenues, management expects operating losses and negative cash flows from operations to continue for the foreseeable future. There can be no assurance that, in the event the Company requires additional financing, such financing will be available at terms acceptable to the Company, if at all. Failure to generate sufficient cash flows from operations, raise additional capital and reduce discretionary spending should additional capital not become available could have a material adverse effect on the Company’s ability to achieve its business objectives.

f) Revenue Recognition

Product Revenue, net

The Company recognizes revenue in accordance with FASB Accounting Standards Codification (“ASC”) Topic 606,Revenue from Contracts with Customers (“ASC 606”). Revenue is recognized at a point in time when the customer obtains control of promised goods or services in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligation(s) in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract; and (v) recognize revenue when (or as) the Company satisfies its performance obligation(s).

The Company’s product revenues for the three months ended March 31, 2026 relate to sales of CARDAMYST. The Company recognizes revenue on product sales when control of the promised goods is transferred to its customers in an amount that reflects the consideration expected to be received in exchange for transferring those goods. The Company accounts for a contract when it has approval and commitment from both parties, the rights of the parties are identified, payment terms are identified, the contract has commercial substance and collectability of consideration is probable. When determining whether the customer has obtained control of the goods, the Company considers any future performance obligations.

Revenue is recorded net of variable consideration, which includes prompt pay discounts, distribution fees, returns, chargebacks, rebates, co-payment assistance, and patient assistance programs. The variable consideration is estimated based on contractual terms as well as management assumptions. The amount of variable consideration is calculated by using the expected value method, which is the sum of probability-weighted amounts in a range of possible outcomes, or the most likely amount method, which is the single most likely amount in a range of possible outcomes. Estimates are reviewed quarterly and adjusted as necessary.

Accruals are established for gross to net deductions and actual amounts incurred are offset against applicable accruals. The Company reflects these accruals as either a reduction in the related account receivable from the customer or as an accrued liability, depending on the means by which the deduction is settled. Sales deductions are based on management’s estimates that involve a substantial degree of judgment.

Prompt Pay: Customers receive a prompt pay discount for payments made within a contractually agreed number of days before the due date. The discounts are accounted for as a reduction of the transaction price and recorded as a contra-receivable.

*Distribution fees:*The Company compensates its customers for distribution of its products and the use of data. The Company has determined that such services received to date are not distinct from its sale of products and may not reasonably represent fair value for these services. Therefore, estimates of these payments are recorded as a reduction of revenue based on contractual terms.

Returns: The Company records allowances for product returns as a reduction of revenue at the time product sales are recorded. Product returns are estimated based on forecasted sales and historical and industry data. Returns are permitted in accordance with the return of goods policy defined within each customer agreement. A returns reserve is recorded as an accrued liability.

Chargebacks: The Company estimates obligations resulting from contractual commitments with the government and other entities to sell products to qualified healthcare providers at prices lower than the list prices charged to the customer who directly purchases from the Company. The customer charges the Company for the difference between what it pays to the Company for the product and the selling price to the qualified healthcare providers, with the difference recorded as a contra receivable.

Co-payment assistance and patient assistance programs: Patients who have commercial insurance and meet certain eligibility requirements may receive co-payment assistance. Based upon the terms of the program and co-payment assistance utilization reports received, the Company estimates the co-payment assistance amounts, which are recorded in the same period in which the related revenue is recognized, resulting in a reduction of product revenue and establishment of a current liability.

Rebates: The Company’s rebates include amounts paid to managed care organizations, Medicaid, Medicare, and other rebate programs. Reserves for rebates are recorded in the same period the related product revenue is recognized,

resulting in a reduction of product revenues and a current liability that is included in accrued liabilities on the consolidated balance sheet. The Company’s estimate for rebates is based on statutory or contractual discount rates, expected utilization or an estimated number of patients on treatment, as applicable.

License Revenue

The Company recordedno license revenue for either of the three months ended March 31, 2026 and 2025.

In prior periods, the Company recognized license revenue upon achievement of milestones under its License and Collaboration Agreement, dated May 15, 2021 (the “Ji Xing License Agreement”), with Corxel Pharmaceuticals (formerly known as Ji Xing Pharmaceuticals Limited, “Ji Xing”). On March 23, 2026, Corxel announced that it had entered into an Asset Purchase Agreement with Everest Medicines (“Everest”), pursuant to which Everest acquired the rights to develop, manufacture and commercialize CARDAMYST™ (etripamil) nasal spray in Greater China, including mainland China, Hong Kong, Macau and Taiwan.

No milestones were achieved under the Ji Xing License Agreement during either of the three months ended March 31, 2026 and 2025. For additional information regarding the license agreement, see Note 3, “Revenue,” to the Company’s audited consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

g) Cost of Product Sales

Cost of product sales includes the costs of producing inventory related to CARDAMYST, including manufacturing, freight, overhead, and any inventory valuation adjustments, and is recognized in the period in which the related product revenue is earned.

Prior to FDA approval of CARDAMYST on December 12, 2025, all manufacturing costs were expensed as research and development costs. As a result, inventory on hand at the time of approval had a zero-cost basis.

For the three months ended March 31, 2026, the Company recognized a de minimis amount of cost of product sales, consisting primarily of post-approval manufacturing activities, including final packaging costs. Accordingly, cost of product sales for the period may not be indicative of the full cost of units sold, and gross margin may not be representative of future periods. The Company recordedno cost of product sales for the three months ended March 31, 2025.

h) Royalty Financing Obligation

The royalty financing obligation is required to be repaid based on royalties from net sales of CARDAMYST in the United States under the Royalty Purchase Agreement with RTW – see Note 11, “Royalty Financing Obligation,” for further details on the Royalty Purchase Agreement. Interest expense is accrued using the effective interest rate method over the estimated period of royalty payments. This requires the Company to estimate the total amount of future royalty payments to be generated from product sales in the United States over the estimated repayment term of the obligation. The Company imputes interest on the carrying value of the royalty financing obligation and records interest expense using an imputed effective interest rate. The Company reassesses the expected royalty payments each reporting period and accounts for any changes through adjustments to the effective interest rate on a prospective basis. The assumptions used in determining the estimated repayment term of the debt require that the Company make estimates which could impact the carrying value of the obligation. A significant increase or decrease in forecasted net sales could materially impact the liability balance, interest expense, and the time period for repayment.

i) Concentration Risks

Concentration of Credit Risk

Financial instruments that potentially subject the Company to concentration of credit risk consist primarily of cash and cash equivalents and investment securities classified as held-to-maturity. The Company maintains deposits at major financial institutions and such amounts may exceed those amounts insured by the Federal Deposit Insurance Corporation, or the “FDIC.” The Company has not experienced any losses on its deposits since inception, and the Company believes that minimal credit risk exists with respect to these financial institutions. Additionally, the Company has adopted an investment policy that includes guidelines relative to credit quality, diversification of maturities and liquidity.

Concentration of Supplier Risk

The Company relies on a single source manufacturer for starting materials and active pharmaceutical ingredient, or “API,” packaging components, and packaged pharmaceutical product ready for commercial sale.

j) Inventory

Inventory is stated at the lower of cost or net realizable value, with cost determined on a first-in, first-out, or “FIFO,” basis. Inventory costs include raw materials, work-in-process, finished goods, and applicable manufacturing overhead. Raw materials include starting materials used to manufacture the API. Work-in-process includes API, intermediate compounding steps, and bulk drug product. Finished goods include packaging components and the packaged pharmaceutical product ready for commercial sale.

Prior to the FDA’s approval of CARDAMYST on December 12, 2025, costs associated with manufacturing pre-approval commercial batches and clinical materials were expensed as research and development expenses in accordance with the Company’s accounting policy and SAB Topic 5A, as the product had not yet received regulatory approval and therefore did not meet the criteria for capitalization. Following FDA approval, the Company began capitalizing inventory related to CARDAMYST manufactured after the approval date. Inventory produced prior to approval and previously expensed as research and development remains recorded at a zero-cost basis and is excluded from the inventory balance.

Because the Company’s inventory is subject to expiration, the Company evaluates its carrying value each reporting period and records allowances for any estimated excess, obsolete, short-dated, or otherwise unmarketable inventory. In accordance with regulatory requirements and current Good Manufacturing Practices, or “cGMP,” the Company’s inventory is also subject to strict quality control and monitoring throughout the manufacturing process. If certain batches or units do not meet quality specifications, the Company would write down the related inventory to its estimated net realizable value and record the expense as a cost of production in the Consolidated Statement of Loss. Inventory valuation adjustments require judgment and consideration of various factors, including forecasted demand, remaining shelf life, and quality assessments, among others.

k) Income Taxes

The provision for income taxes is computed using the liability method. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is recorded to reduce the carrying amount of deferred income tax assets until when it is more likely than not that these assets will be realized. Tax benefits related to tax positions not deemed to meet the “more likely than not” threshold are not permitted to be recognized in the consolidated financial statements.

For interim reporting, the Company estimates its annual effective tax rate, adjusted for discrete items, and applies that rate to its year-to-date pre-tax income (loss) to determine its income tax provision.

3. Revenues

The Company recorded product revenues from the U.S. sales of CARDAMYST of $0.2 million for the three months ended March 31, 2026, andno revenue for the three months ended March 31, 2025.

The Company recordedno license revenue for the three months ended March 31, 2026, and 2025, respectively.

4. Short-term Investments

As of March 31, 2026, short-term investments of $112.9 million were comprised of term deposits issued in U.S. currency, earning interest between 2.61% and 4.48%, maturing between April 21, 2026 and March 9, 2027. These short-term investments were in scope of ASC 320,Investments-Debt Securities. The short-term investments maturity is greater than 90 days but less than one year, and they were classified as held to maturity, recorded as current assets and were accounted for at amortized cost. Interest income earned on short-term investments is reported in interest income. The Company had short-term investments of $32.9 million as of December 31, 2025.

As of March 31, 2026, $0.9 million in short-term investments were pledged as collateral for a letter of credit.

5. Inventory

As of March 31, 2026 and December 31, 2025, the Company’s inventory consisted entirely of CARDAMYST related inventory. The Company’s inventories consisted of the following:

**6.**Debt

On March 27, 2023, the Company entered into a note purchase agreement, or the “Note Purchase Agreement,” with RTW Investments LP and certain of its affiliates, or collectively, “RTW.” On March 29, 2023, the Company closed the transactions contemplated by the Note Purchase Agreement, and issued and sold $50.0 million principal amount of 6.0% Convertible Senior Notes due 2029, or the “2029 Convertible Notes,” to the holders. For more details on the agreement with RTW, see Note 11, “Debt,” to the Company’s audited consolidated financial statements, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

In accounting for the issuance of the 2029 Convertible Notes, the Company determined there were no embedded features, which require bifurcation between debt and equity components. As a result, the 2029 Convertible Notes are accounted for as a liability. As of March 31, 2026, the estimated fair value of the 2029 Convertible Notes was approximately $58.4 million based on level 2 inputs, including volatility and credit spread.

The net carrying amount of the 2029 Convertible Notes are as follows:

The following table presents the total amount of interest cost recognized relating to the 2029 Convertible Notes:

7. Accrued Liabilities

Accrued liabilities are comprised of the following:

8. Shareholders’ Equity

Authorized Share Capital

The Company has authorized and issued common shares, voting and participating, without par value, of which unlimited shares were authorized, and 117,794,417 shares were issued and outstanding as of March 31, 2026.

As of March 31, 2026, there were 2,774,440 common shares available for issuance under the Employee Stock Purchase Plan, or the “ESPP,” of which 2,145,794 are available for future purchases.

On July 11, 2025, the Company entered into an underwriting agreement, or the “Underwriting Agreement,” related to an underwritten public offering, or the “2025 Offering,” of (i)31,500,000 of the Company’s common shares, without par value, accompanying Series A common warrants, or the “Series A Common Warrants,” to purchase an aggregate of

31,500,000 common shares and accompanying Series B common warrants, or the “Series B Common Warrants,” to purchase an aggregate of 31,500,000 common shares, at a combined public offering price of $1.50 per share and accompanying Series A Common Warrant and Series B Common Warrant and (ii) in lieu of common shares to certain investors that so choose, pre-funded warrants to purchase 3,502,335 common shares, or the “2025 Pre-Funded Warrants” and, together with the Series A Common Warrants and the Series B Common Warrants, the “Warrants,” accompanying Series A Common Warrants to purchase an aggregate of 3,502,335 common shares and accompanying Series B Common Warrants to purchase an aggregate of 3,502,335 common shares, at a combined public offering price of $1.499 per Pre-Funded Warrant and accompanying Series A Common Warrant and Series B Common Warrant, which represented the combined public offering price for the Shares and accompanying common warrants less the $0.001 per share exercise price for each such Pre-Funded Warrant. All the Securities sold in the 2025 Offering were sold by the Company.

The net proceeds to the Company from the 2025 Offering were $48.6 million after deducting underwriting commissions and other offering expenses payable by the Company, in the amount of $3.9 million.

On July 29, 2020, the Company entered into an Open Market Sale Agreement SM, or the “Original Sale Agreement,” with respect to an at-the-market offering program, or the “ATM Program,” under which the Company could issue and sell its common shares having an aggregate offering price of up to $50.0 million. On March 18, 2025, the Company entered into an Amended and Restated Open Market Sale Agreement SM, or the “Amended Agreement.” Under the Amended Agreement, the Company may issue and sell its common shares, no par value per share, for an aggregate offering price of up to $77.8 million (which includes the approximately $2.8 million of sales previously made pursuant to the Original Sale Agreement through the date the Amended Agreement was entered into), or the “ATM Shares.” As disclosed in Note 21, “Subsequent Events,” to the Company’s audited consolidated financial statements, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, the Company issued 5,526,590 shares under the amended agreement resulting in net proceeds of $10.9 million, after deducting sales agent commissions payable by the Company of $0.3 million during the three-month period ended March 31, 2026. On March 6, 2026, the Company terminated the Amended Agreement.

The Company determines the accounting classification of warrants that are issued, as either liability or equity, by first assessing whether the warrants meet liability classification in accordance with ASC 480-10,Accounting for Certain Financial Instruments with Characteristics of both Liabilities and Equity, and then in accordance with ASC 815-40,Accounting for Derivative Financial Instruments Indexed to, and Potentially Settled in, a Company’s Own Stock. Under ASC 480, warrants are considered liability classified if the warrants are mandatorily redeemable, obligate the issuer to settle the warrants or the underlying shares by paying cash or other assets, or must or may require settlement by issuing a variable number of shares.

If warrants do not meet liability classification under ASC 480-10, the Company assesses the requirements under ASC 815-40, which states that contracts that require or may require the issuer to settle the contract for cash are liabilities recorded at fair value, irrespective of the likelihood of the transaction occurring that triggers the net cash settlement feature. If the warrants do not require liability classification under ASC 815-40, in order to conclude equity classification, the Company assesses whether the warrants are indexed to its common stock and whether the warrants are classified as equity under ASC 815-40 or other applicable U.S. GAAP. After all relevant assessments are made, the Company concludes whether the warrants are classified as liability or equity. The Company's outstanding common stock warrants are classified as equity and recorded in additional paid-in capital, or “APIC,” based on an allocation of the proceeds from the 2025 Offering, which was based on the relative fair value of the Series A and B Common Warrants at the issuance date and is not subject to change after the issuance date. The fair value used for the relative fair value allocation was calculated using the Black-Scholes Model for the Series A Warrants and the Monte-Carlo simulation method for the Series B Warrants.

During the three-month period ended March 31, 2026,5,666,666 Series A Common Warrants were exercised for net proceeds of $8.0 million, after deducting underwriting commissions paid and payable by the Company of $0.5 million. As

of March 31, 2026,15,705,662 Series A Common Warrants and 34,335,669 Series B Common Warrants remained outstanding.

9. Share-Based Compensation

Stock Options

Under the Company’s 2019 Equity Incentive Plan, or the “2019 Plan,” and the Company’s Stock Option Plan, or the “2011 Plan,” unless otherwise decided by the Company’s board of directors, options vest and are exercisable as follows:25%vest and are exercisable on the one year anniversary of the grant date andone thirty-sixth (1/36 th) of theremaining options vest and are exercisable each month thereafter, such that options are vested in full onfour-year anniversary of the grant date.

Under the 2019 Plan,183,349 options have been forfeited or expired under the 2011 Plan since the adoption of the 2019 Plan and have become available for issuance under the 2019 Plan. Further, since the adoption of the plan,561,000 of previously issued options were cancelled and were made available for future grants. As of March 31, 2026, there were 15,714,455 common shares available for issuance under the 2019 Plan, of which 1,482,710 common shares were available for future grants.

On November 10, 2021, the Company established a 2021 Inducement Plan, or the “Inducement Plan.” This 2021 Inducement Plan is intended to help the Company provide an inducement for certain individuals to enter employment with the Company, incentives for such persons to exert maximum efforts for the success of the Company and a means by which employees may benefit from increases in value of the common shares. On March 17, 2026, the Company’s board of directors approved an increase to the 2021 Inducement Plan pool of 800,000 shares. As of March 31, 2026, there were 1,129,000 shares available for issuance under the 2021 Inducement Plan, of which 671,000 shares were available for future grants.

The total outstanding and exercisable options from the 2011 Plan, 2019 Plan, and Inducement Plan as of and for the three-month periods ending March 31 were as follows:

The weighted average remaining contractual life was 6.9 and 6.9 years for outstanding options as of March 31, 2026 and 2025, respectively. The weighted average remaining contractual life was 5.5 and 6.0 years for vested options, as of March 31, 2026 and 2025, respectively.

There was $7.3 million and $7.4 million of total unrecognized compensation cost related to non-vested share options as of March 31, 2026 and 2025, respectively. The share options are expected to be recognized over a remaining weighted average vesting period of 2.97 years and 2.09 years as of March 31, 2026 and 2025, respectively.

Options granted are valued using the Black-Scholes option pricing model. This model also requires assumptions, including expected option life, volatility, risk-free interest rate, and dividend yield, which greatly affect the calculated values. Amortization of the fair value of the options over vesting years has been expensed and credited to additional paid-in capital in shareholders’ equity.

The non-vested options as of and for the three-month period ending March 31 were as follows:

The fair value of options granted for the 2011 Plan, 2019 Plan and Inducement Plan were estimated using the Black-Scholes option pricing model, resulting in the following weighted average assumptions for the options granted:

Expected volatility is determined using the Company’s historical volatility. Prior to establishing sufficient historical volatility, the Company used comparable companies for which the information is publicly available. The risk-free interest rate is determined based on the U.S. sovereign rates benchmark in effect at the time of grant with a remaining term equal to the expected life of the option. Expected option life is determined based on the simplified method as the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate expected term. The simplified method is an average of the contractual term of the options and its ordinary vesting period. Dividend yield is based on the share option’s exercise price and expected annual dividend rate at the time of grant. The total grant date fair

value for options granted during the three-months ended March 31, 2026 and 2025 was $4.4 million and $2.3 million, respectively.

Performance Stock Options

On May 6, 2024, the Company, pursuant to the 2019 Plan, awarded 924,000 performance stock options to employees. The performance stock options were granted “at-the-money” and have a term of 10 years.

The original grant-date fair value of each option was estimated on the date of grant using the same option valuation model used for the options outlined above. The original grant-date fair value of $1.3 million was determined using an expected volatility of 98.5%, term of 5.82 years, strike price of $1.74, and risk-free rate of 4.43%. Compensation expense for performance-based stock options is only recognized when management determines it is probable that the awards will vest.

The vesting of the performance-based stock options was conditional upon the FDA approval of etripamil. Subject to the option-holder’s continuous service as of each such date,50% of the option shares will vest on thesix-month anniversary of the approval date and the remaining 50% of the option shares will vest on theone-year anniversary of such approval date. The weighted average grant date fair value of the performance stock options awarded was $1.38 per option. The Company recorded $0.1 million of expense related to the performance-based stock options during the three months ended March 31, 2026, as the performance conditions were met with FDA approval of etripamil for the treatment of PSVT on December 12, 2025. The Company did not record any expense related to the performance-based stock options during the three months ended March 31, 2025 as the performance conditions were not deemed probable of being met. No performance stock options were awarded for the three months ended March 31, 2026 and 2025.

Employee Stock Purchase Plan

On July 15, 2022, the Company offered an ESPP, in which participation is available to the Company’s employees in the United States and Canada who meet certain service eligibility requirements. Eligible employees may authorize an amount up to 15% of their salary to purchase common shares at the lower of a 15% discount to the beginning price of the participation period or a 15% discount to the ending price of eachsix-month purchase interval. The ESPP also provides for an automatic reset feature to start participants on a newtwelve-month participation period in the event that the common share market value on a purchase date is less than the common shares value on the first day of thetwelve-month offering period.

On January 1, 2026, the number of common shares reserved for issuance under the ESPP automatically increased by 487,837 shares. During the three months ended March 31, 2026, the Company terminated the ongoing ESPP offering effective in March after the completion of the first purchase period and recognized a de minimis amount of incremental stock-based compensation expense related to the unamortized compensation costs of the cancelled period. Compensation expense for purchase rights under the ESPP related to the purchase discount and the “look-back” option was determined using a Black-Scholes option pricing model. As of March 31, 2026,628,646 common shares have been issued under the ESPP.

Performance Share Units

On May 6, 2024, the Company, pursuant to the 2019 Plan, awarded 924,000 Performance Share Units, or “PSUs,” to employees. The PSUs vest subject to the satisfaction of certain performance conditions established by the Company’s Compensation Committee. The FDA approval of etripamil represents the performance condition for the vesting of these PSUs. As a result of the FDA approval on December 12, 2025,100% of the outstanding PSUs vested at a grant date fair value of $1.74 per share. No additional PSUs were awarded for the three months ended March 31, 2026.

Restricted Stock Units

Pursuant to the 2019 Plan, the Company issues restricted stock units, or “RSUs,” to employees which vest based on a service criteria. When vested, the RSUs represent the right to be issued a number of shares of the Company’s common shares equal to the number of RSUs granted. The grant date fair value for RSUs is based on the market price of the Company’s common shares on the date of the grant. The fair value is then amortized to compensation expense over the requisite service period or vesting term.

The total outstanding RSUs from the 2019 Plan as of and for the three-month period ending March 31 were as follows:

The total unrecognized compensation cost related to the non-vested RSUs as of March 31, 2026, was $4.4 million and will be recognized over a weighted average period of approximately 3.50 years. The total unrecognized compensation cost related to the non-vested RSUs as of March 31, 2025 was $1.9 million and will be recognized over a weighted average period of approximately 3.8 years.

Share-based Compensation Expense

The Company recognized total share-based compensation expense for all plans as follows:

10. Net Loss Per Share

Basic and diluted net loss per common share is determined by dividing net loss applicable to common shareholders by the weighted average number of common shares and pre-funded warrants outstanding during the period. In addition to the conversion feature on the 2029 Convertible Notes and common warrants described in Note 8, “Shareholders’ Equity,” which the Company reviewed and concluded would be anti-dilutive if converted or exercised due to the facts surrounding the instruments, the following potentially dilutive securities have also been excluded from the computation of diluted weighted average shares outstanding as of March 31, as they would be anti-dilutive:

Amounts above reflect the common share equivalents of the noted instruments.

11. Royalty Financing Obligation

On March 27, 2023, the Company entered into a purchase and sale agreement, or the “Royalty Purchase Agreement,” with RTW and certain of its affiliates.

Pursuant to the Royalty Purchase Agreement, RTW agreed to purchase, following the FDA approval of etripamil (subject to certain conditions), at a purchase price of $75.0 million, the right to receive a tiered quarterly royalty payments, or the “Royalty Interest,” on the net product sales of etripamil in the United States in an amount equal to: (i)7%, or the “Initial Tier Royalty,” of annual net sales up to $500 million, (ii)4% of annual net sales greater than $500 million and less than or equal to $800 million, and (iii)1% of annual net sales greater than $800 million. If certain revenue thresholds for aggregate annual net sales are not met, the Initial Tier Royalty will increase to 9.5% beginning on January 1 of the following calendar year until a subsequent sales threshold is attained, at which time the Initial Tier Royalty would revert back to 7%.

On January 12, 2026, the Company closed the sale of the Royalty Interest under the Royalty Purchase Agreement and received the $75.0 million purchase price.

The cash consideration obtained pursuant to the Royalty Purchase Agreement is recorded in “Royalty financing obligation” on the Company’s Condensed Consolidated Balance Sheets. Upon initial recognition, the royalty financing obligation was recorded based on the proceeds received. The Company subsequently measures the royalty financing obligation at amortized cost using the effective interest method. As of March 31, 2026, the carrying value of the royalty financing obligations under the Royalty Purchase Agreement approximated its fair value. The estimated fair value of the royalty financing obligations was based on the Company’s current estimates of future payments to RTW over the estimated term of the obligation, which are considered Level 3 inputs.

The Company utilizes the prospective method to account for subsequent changes in the estimated future royalties to be paid by the Company to the counterparty over the estimated term of the obligation. Under the prospective method, a new effective interest rate is determined based on the revised estimate of remaining cash flows. The new rate is the discount rate that equates the present value of the revised estimate of remaining cash flows with the carrying amount of the debt, and it will be used to recognize interest expense for the remaining periods. If the amount or timing of expected royalty payments differs from prior estimates, the Company will prospectively adjust the amortization of the royalty financing obligations and the effective interest rate. On a quarterly basis, the Company assesses the projected royalty payments relative to the projected interest accretion for the next twelve months to determine if the royalty liability balance needs to be reduced relative to the current outstanding liability. In such case of excess payments relative to interest accretion for the next twelve months, the excess payments are considered to be a short-term liability and classified within current liabilities on the Company’s Condensed Consolidated Balance Sheets.

During the three months ended March 31, 2026, there were no significant changes to the amount and timing of expected royalties under the Royalty Purchase Agreement based on the Company’s latest forecasts subsequent to the initial measurement.

The following table shows the royalty financing obligation activity for the three months ended March 31, 2026 as well as the effective interest rate as of March 31, 2026:

12. Other** Receivables**

Other receivables are comprised of the following:

13. Segment Reporting

The Company manages its operations as asingle operating segment for the purpose of assessing performance and making operating decisions while focusing on the development and commercialization of innovative cardiovascular medicines. These operations, which are reported on a consolidated basis, are focused on a single product. The accounting policies of the single operating segment are the same as those described in the summary of significant accounting policies. The chief operating decision maker, or “CODM,” assesses performance of the Company’s single operating segment based on consolidated net loss. Net loss is used by the CODM to evaluate budget to actual analytics, which are used to monitor expenditures and ensure the Company is meeting established budgets. The CODM is the principal officer group, which includes the Company’s chief executive officer and chief financial officer.

The following table presents information about the Company’s significant segment expenses, as provided to the Company’s CODM, and includes a reconciliation to consolidated net loss:

The measure of segment assets is reported on the balance sheet as total consolidated assets.

14. Fair value of financial instruments

Pursuant to the accounting guidance for fair value measurement and its subsequent updates, fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (i.e. the exit price) in an orderly transaction between market participants at the measurement date. The accounting guidance establishes a hierarchy for inputs used in measuring fair value that minimizes the use of unobservable inputs by requiring the use of observable market data when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on active market data. Unobservable inputs are inputs that reflect the assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances.

The fair value hierarchy is broken down into the three input levels summarized below:

For the three months ended March 31, 2026 and 2025, there wereno financial instruments measured at fair value on a recurring or non-recurring basis. The carrying amounts of certain financial instruments, including cash and cash equivalents, short-term investments, accounts receivable, accounts payable and accrued expenses approximate their fair values due to the short-term nature of such instruments. Refer to Note 6, “Debt,” for disclosure of the fair value of the 2029 Convertible Notes and Note 11, “Royalty Financing Obligation,” for disclosures about the royalty financing obligation. The estimated fair value of the royalty financing obligations is based on the Company’s current estimates of future payments to RTW over the estimated term of the obligation, which are considered Level 3 inputs.

15. Subsequent Event

Warrants Exercised

Subsequent to the three-month period ended March 31, 2026, through to the date of issuance of the condensed consolidated financial statements, the Company raised aggregate gross proceeds of $10.0 million from the exercise of Series A Common Warrants previously issued in connection with the 2025 Offering. Specifically,6,678,642 Series A Warrants were exercised for net proceeds of $9.4 million, after deducting underwriting commissions payable by the Company of $0.6 million.

Controlled Equity Offering

On May 13, 2026, the Company entered into a Controlled Equity Offering SMSales Agreement, or the "Sales Agreement," with Cantor Fitzgerald & Co., as sales agent, or the "Sales Agent," pursuant to which the Company may, from time to time, sell common shares, without par value per share, through the Sales Agent, or the “ATM Offering”. The Company will pay the Sales Agent a commission for its services as Sales Agent of 3.0% of the aggregate gross proceeds from each sale of the common shares sold through the Sales Agent pursuant to the Sales Agreement.