Lantheus Holdings, Inc.

Note Regarding Company References and Trademarks

Unless the context otherwise requires, references to the “Company,” “our Company,” “Lantheus,” “we,” “us” and “our” refer to Lantheus Holdings, Inc. and its direct and indirect wholly-owned subsidiaries; references to “Lantheus Holdings” refer to Lantheus Holdings, Inc. and not to any of its subsidiaries; references to “Lantheus Medical” refer to Lantheus Medical Imaging, Inc., the wholly-owned subsidiary of Lantheus Holdings; references to “Aphelion,” “Cerveau,” “Evergreen,” “Lantheus Alpha,” “Lantheus Radiopharm UK,” “Lantheus Real Estate,” “Lantheus Three,” “Lantheus Two,” and “Progenics” refer to Aphelion LLC; Cerveau Technologies, Inc.; Evergreen Theragnostics, Inc.; Lantheus Alpha Therapy, LLC; Lantheus Radiopharmaceuticals UK Limited; Lantheus MI Real Estate, LLC; Lantheus Three, LLC; Lantheus Two, LLC; and Progenics Pharmaceuticals, Inc., respectively, each a wholly-owned subsidiary of Lantheus Medical; references to “Lantheus Biosciences” refer to Lantheus Biosciences Ltd. (or to Life Molecular Imaging Limited prior to the Company’s acquisition of it in July 2025 and a name change in February 2026), a wholly-owned subsidiary of Lantheus Radiopharm UK.

Solely for convenience, the Company refers to trademarks, service marks and trade names in this Quarterly Report on Form 10-Q (“Form 10-Q”) without the TM, SM and ® symbols. Those references are not intended to indicate, in any way, that the Company will not assert, to the fullest extent permitted under applicable law, its rights to its trademarks, service marks and trade names. Each trademark, service mark or trade name of any other company appearing in this Form 10-Q, is, to the Company’s knowledge, owned by that other company.

1. Basis of Presentation

The accompanying unaudited condensed consolidated financial statements include the accounts of Lantheus and have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Accordingly, these condensed consolidated financial statements do not include all of the information and notes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal and recurring adjustments) considered necessary for a fair statement have been included. The preparation of the Company’s condensed consolidated financial statements requires management to make certain estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue and expenses, and related disclosures. The results of operations for thethree and nine months ended September 30, 2026 and 2025 are not necessarily indicative of the results that may be expected for any future period.

The condensed consolidated balance sheet at December 31, 2025 has been derived from the audited consolidated financial statements at that date but does not include all the information and notes required by U.S. GAAP for complete financial statements. These condensed consolidated financial statements and accompanying notes should be read in conjunction with the consolidated financial statements and notes thereto included in Item 8 of the Company’s most recent Annual Report on Form 10-K (“Form 10-K”) for the year ended December 31, 2025 filed with the Securities and Exchange Commission (“SEC”) on February 26, 2026.

2. Summary of Significant Accounting Policies

Equity Investments Without Readily Determinable Fair Values

The Company accounts for investments in equity instruments that do not have a readily determinable fair value and do not provide the Company with control or significant influence under the measurement alternative, defined as cost, less impairment, adjusted for subsequent observable price changes. The Company assesses relevant transactions that occur on or before the balance sheet date to identify observable price changes, and regularly monitors these investments to evaluate whether there is an indication that the investment is impaired.

Recent Accounting Pronouncements

The Company has considered the applicability and impact of all new Accounting Standards Updates (“ASUs”) issued by the Financial Accounting Standards Board (“FASB”). ASUs not discussed below were assessed and determined to be either not applicable or are expected to have minimal impact on the Company’s consolidated financial statements.

Accounting Pronouncements Adopted During the Period

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 related to the estimation of expected credit losses for accounts receivable and current contract assets that arise from transactions accounted for under Accounting Standards Codification (“ASC”) 606,“Revenue from Contracts with Customers.”ASU 2025-05 requires an entity to disclose whether it has elected to use the practical expedient. An entity that makes the accounting policy election is required to disclose the date through which subsequent cash collections are evaluated. The

Company adopted ASU 2025-05 effective January 1, 2026 on a prospective basis and elected the practical expedient for the calculation of expected credit losses for the Company’s current accounts and notes receivables. Adoption of this standard did not have a material impact on the Company’s condensed consolidated financial statements and related disclosures during the nine months ended September 30, 2026.

In November 2024, the FASB issued ASU 2024-04, “Debt - Debt with Conversion and Other Options (Subtopic 470-20),”which clarifies the requirements for determining whether certain settlements of convertible debt instruments should be accounted for as an induced conversion rather than as extinguishment of debt. The requirements of ASU 2024-04 are effective for the annual periods beginning after December 15, 2025, including interim periods within those fiscal years. The Company prospectively adopted ASU 2024-04 as of January 1, 2026. The adoption did not have a material impact on the Company’s condensed consolidated financial statements during the nine months ended September 30, 2026, as the Company has not entered into any exchange-related settlements, modifications, or inducement transactions related to its 2.625% Convertible Senior Notes due December 2027. However, the Company will utilize this guidance for any future induced conversions or extinguishments of these notes.

Accounting Pronouncements Not Yet Adopted

In December 2025, the FASB issued ASU 2025-11,“Interim Reporting (Topic 270) Narrow-Scope Improvements,”which clarifies that the interim reporting requirements in Topic 270 apply to all entities that issue interim financial statements prepared in accordance with U.S. GAAP and consolidates such requirements within Topic 270. The amendments provide a comprehensive list within Topic 270 of required interim disclosures, establishes a principle requiring disclosure of events or changes occurring after the end of the most recent annual reporting period that have a material impact on interim results and clarify the form and content requirements applicable to interim financial statements. The requirements of ASU 2025-11 are effective for interim reporting periods within annual reporting periods beginning after December 15, 2027 (for the Company’s Form 10-Q for the three months ending March 31, 2028). The Company is currently in the process of evaluating the effects of this pronouncement on its consolidated financial statements and related disclosures.

In September 2025, the FASB issued ASU 2025-06,“Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software,”which simplifies the capitalization guidance by removing all references to software development project stages so that the guidance is neutral to different software development methods. Entities will now capitalize costs associated with internal-use software only when management has authorized and committed funding, and it is probable that the project will be completed and the software will be used to perform its intended function. ASU 2025-06 is effective for interim and annual periods beginning after December 15, 2027, with early adoption permitted. The Company is currently in the process of evaluating the effects of this pronouncement on its consolidated financial results and related disclosures.

In November 2024, the FASB issued ASU 2024-03, “Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40),”and in January 2025, the FASB issued ASU 2025-01,“Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Clarifying the Effective Date.”ASU 2024-03 requires additional income statement disclosures, including the disaggregation of specific categories of expenses underlying the line items presented on the income statement. Additionally, ASU 2024-03 requires enhanced disclosure of selling expenses. As clarified by ASU 2025-01, the requirements of the guidance are effective for annual periods beginning after December 15, 2026 and interim periods within fiscal years beginning after December 15, 2027. For the Company, annual reporting requirements under ASU 2024-03 will be effective for its Form 10-K for the year ending December 31, 2027 and interim reporting requirements will be effective beginning in the first quarter of 2028. Early adoption is permitted and the amendments should be applied on a prospective basis; however retrospective application is permitted. The Company is currently in the process of evaluating the impact of this pronouncement on its consolidated financial results and related disclosures.

3. Revenue from Contracts with Customers

Disaggregation of Revenue

The following table summarizes revenue by source as follows:

(1)

The Company’s product revenue includes PYLARIFY, Neuraceq, DEFINITY, and prior to January 1, 2026, TechneLite, among other products. TechneLite was sold in connection with the Company’s sale of its single-photon emission computerized tomography (“SPECT”) business to SHINE Technologies, LLC (“SHINE”), a wholly-owned subsidiary of Illuminated Holdings, Inc. (“Illuminated”), on January 1, 2026. This category represents the delivery of physical goods. The Company applies the same revenue recognition policies and judgments for all its principal products.

Prior to January 1, 2026, the Company classified its revenues into three product categories: Radiopharmaceutical Oncology, Precision Diagnostics, and Strategic Partnerships and Other Revenue. Following the Company’s sale of its SPECT business on January 1, 2026, the Company classifies its revenues into four product categories: Oncology, Neurology, Cardiology, and Strategic Partnerships and Other Revenue. The change in classification reflects the Company’s current business structure subsequent to its acquisition of two companies in 2025 and the sale of the SPECT business. The Company has presented the prior year numbers for revenues to conform with its current year presentation, including the disaggregation of revenue related to its sale of the SPECT business.

Revenue by product category on a net basis is as follows:

The following table presents the Company’s revenue by geographic region determined by location of customer or other party for the periods presented:

Product Returns

The Company generally offers customers a limited right of return due to non-conforming product. The Company estimates the amount of its product sales that may be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product return liabilities using its historical product return information and considers other factors that it believes could significantly impact its expected returns, including product recalls. Reserves for product returns are not significant to the Company due to the nature of its products including radiopharmaceutical products with limited half-lives.

Rebates

Estimates for rebates represent the Company’s estimated obligations under contractual arrangements with third parties. Rebate accruals are recorded in the same period the related revenue is recognized, resulting in a reduction of revenue and the establishment of a liability which is included in accrued expenses and other current liabilities in the Company’s condensed consolidated balance sheets. These rebates result from performance-based offers that are primarily based on attaining contractually specified sales volumes or market share, Medicaid rebate programs for the Company’s products, administrative fees of group purchasing organizations and certain distributor-related commissions. The calculation of the accrual for these rebates is based on an estimate of the third-party’s expected purchases and the resulting applicable contractual rebate to be earned over a contractual period.

An analysis of the amount of, and change in, accruals for rebate liabilities is summarized as follows:

Contract Assets and Liabilities

The Company recognizes an asset for incremental costs of obtaining a contract with a customer if it expects to recover those costs. The Company’s sales incentive compensation plans qualify for capitalization since these plans are directly related to sales achieved during a period of time. However, the Company has elected the practical expedient to expense these costs as incurred within sales and marketing expenses, because the amortization period is less than one year.

The following table provides a roll forward of deferred revenue:

The Company is required to allocate a portion of its revenue received from commercial contracts to future reporting periods to the extent the Company had performance obligations that extended beyond one year. However, the Company’s performance obligations are typically part of contracts that have an original expected duration of one year or less. Therefore, since the Company elected the practical expedient under ASC 606-10-50-14, it does not disclose information regarding remaining performance obligations for contracts with an original expected duration of one year or less.

4. Fair Value of Financial Instruments

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. In order to increase consistency and comparability of fair value measurements, financial instruments are categorized based on a hierarchy that prioritizes observable and unobservable inputs used to measure fair value into three broad levels, which are described below:

•

Level 1 — Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date.

•

Level 2 — Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.) and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs).

•

Level 3 — Unobservable inputs that reflect the Company’s estimates about the assumptions that market participants would use in pricing the asset or liability. The Company develops these inputs based on the best information available, including its own data.

The Company’s financial assets and liabilities that are measured at fair value on a recurring basis consist of money market funds, deferred compensation plan liabilities, contingent consideration liabilities and equity investments. The Company invests excess cash from its operating cash accounts in overnight investments and reflects these amounts in cash and cash equivalents in the condensed consolidated balance sheets at fair value using quoted prices in active markets for identical assets. Investment in equity securities resulting from the Perspective Therapeutics, Inc. (“Perspective”) and Radiopharm Theranostics Limited (“Radiopharm”) strategic agreements were recorded at fair value by the Company and are adjusted for price changes observable in the market each quarter. The Company measured the Series E-1 convertible preferred stock of Illuminated (the “Series E-1 Preferred”), acquired in April 2026 upon conversion of the promissory note from Illuminated, with a principal amount of $70.0 million that bears no interest and has a maturity date of June 14, 2028 (the “Installment Note”), at their initial fair value, with subsequent carrying value adjustments recorded for impairment and observable price changes. See the section entitled”Installment Note”below for more information about this transaction. The Company recorded the contingent consideration liabilities resulting from the acquisitions of Evergreen and Lantheus Biosciences at fair value based on inputs that are not observable in the market. Consideration received from the sale of the SPECT business on January 1, 2026 was initially measured at fair value. See Note 8,“SPECT Business” for more information about the sale of the SPECT business in the first quarter of 2026.

The tables below present information about the Company’s assets and liabilities measured at fair value on a recurring basis:

Nonqualified Deferred Compensation Plan

The Company maintains the Lantheus Nonqualified Deferred Compensation Plan (the “LDCP”) for the benefit of certain key, highly-compensated employees and non-employee directors. The assets of the LDCP are invested in corporate-owned life insurance (“COLI”) at September 30, 2026 and in COLI and mutual funds at December 31, 2025. The mutual funds are classified as Level 1 of the fair value hierarchy because they are valued using quoted market prices. The liabilities of the LDCP are presented in other long-term liabilities in the Company’s condensed consolidated balance sheets. See Note 16,“Benefit Plans”for more information on the LDCP.

Investments in Equity Securities with Readily Determinable Fair Values

Perspective Therapeutics Inc. Equity Securities

The Company held 8,739,011 shares and 11,677,339 shares of Perspective common stock (“Perspective Shares”) at September 30, 2026 and December 31, 2025, respectively. The Company accounts for its investment in Perspective Shares as an equity investment with a readily determinable fair value, as the securities are publicly traded on the New York Stock Exchange (“NYSE”). The fair value of the Perspective Shares is based on their closing price on the NYSE at the end of the fiscal period and is classified within Level 1 of the fair value hierarchy because the equity securities are valued using quoted market prices. The fair value of the Perspective Shares as of September 30, 2026 was approximately $24.0 million based on a closing market price of $2.75 per share on September 30, 2026. The fair value of the Perspective Shares as of December 31, 2025 was approximately $32.1 million based on a closing market price of $2.75 per share on December 31, 2025. See Note 18,“Acquisitions” for further discussion of the Perspective transaction.

During the three months ended September 30, 2026, the Company received $8.6 million in cash from the sale of 2,938,328 Perspective Shares and realized a loss of $2.3 million, which was recorded within net loss (gain) on investment in equity securities in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026.

Radiopharm Theranostics Limited Equity Securities

The Company held 537,958,513 shares of Radiopharm common stock (“Radiopharm Shares”) as of September 30, 2026. The Company accounts for its investment in Radiopharm Shares as an equity investment with a readily determinable fair value, as the securities are publicly traded on the Australian Securities Exchange (“ASX”). The fair value of the Radiopharm Shares is based on their closing price on the ASX at the end of the fiscal period and is classified within Level 1 of the fair value hierarchy because the equity securities are valued using quoted market prices. The fair value of the Radiopharm Shares as of September 30, 2026 was approximately $2.3 million based on the converted closing market price of approximately $0.004 per share on September 30, 2026 using the exchange rate in effect on that day. The fair value of the Radiopharm Shares as of December 31, 2025 was approximately $9.0 million based on the converted closing market price of approximately $0.02 per share on December 31, 2025 using the exchange rate in effect on that day. See Note 18, “Acquisitions” for further discussion of the Radiopharm transaction.

Contingent Consideration Liabilities

Evergreen Theragnostics, Inc.

Pursuant to the terms of the Agreement and Plan of Merger (the “Evergreen Merger Agreement”) with Evergreen and Shareholder Representative Services LLC governing the Company's acquisition of Evergreen in April 2025 (see Note 18,“Acquisitions”), the Company is required to pay up to $727.5 million in cash upon the achievement of specified milestones in connection with the development and commercialization of certain milestone products, as defined in the Evergreen Merger Agreement, and OCTEVY (also referred to as LNTH-2501), a registrational-stage positron emission tomography (“PET”) diagnostic imaging agent targeting neuroendocrine tumors. The Company records these possible payments as contingent consideration liabilities that are classified within Level 3 of the fair value hierarchy. The Company estimated the fair value of the contingent consideration liabilities associated with the sales milestones using a Monte Carlo simulation in a risk-neutral framework, whereby the achievement of the future revenue associated with the sales milestones was simulated using a geometric Brownian motion model. The Company estimated the fair value of the contingent consideration liability associated with the development and commercialization milestones using a probability-weighted discounted cash flow (“DCF”) approach. The most significant unobservable inputs with respect to these milestone products and OCTEVY, are the revenue volatility and probabilities of achieving regulatory milestones. A significant change in probability of payment of the first regulatory milestone payment for OCTEVY could result in a material fluctuation in the value of the contingent consideration liability.

Lantheus Biosciences Ltd.

Pursuant to the terms of the Sale and Purchase Agreement (the “LMI Purchase Agreement”) with Life Medical Group Limited (“Life Medical”) in connection with the Company’s acquisition of Lantheus Biosciences in July 2025 (see Note 18, “Acquisitions”), the Company is required to make certain earn-out andmilestone payments as a percentage of and upon the achievement of specified net sales thresholds, respectively, of Neuraceq and certain other imaging agents in Lantheus Biosciences’s pipeline. These contingent cash earn-out and milestone payments total up to $400.0 million.

In addition to the net sales earn-out and milestone payments, the Company also assumed a contingent consideration liability owed to Piramal Holdings SA (“Piramal”), pursuant to an assumed contract (the “Piramal SPA”). The Company is required to make cash payments of up to $30.0 million upon the achievement of specified earnings metrics of Lantheus Biosciences, as defined in the Piramal SPA.

The Company estimated the fair value of the contingent consideration liabilities using a Monte Carlo simulation model in a risk-neutral framework, whereby the achievement of the future revenue and other specified earnings metrics associated with the contingent payments were simulated using a geometric Brownian motion model. The most significant unobservable inputs with respect to Neuraceq and other imaging agents in Lantheus Biosciences’s pipeline include revenue volatility and the probability of commercial success. A significant change in the revenue volatility or forecasted commercial revenue could result in a material fluctuation in the value of the contingent consideration liability.

The following table reflects the activity for the Company’s contingent consideration liabilities for these acquisitions, measured at fair value using Level 3 inputs for the nine months ended September 30, 2026:

Significant changes in any of the probabilities of success, the probabilities as to the periods in which sales targets and milestones will be achieved, discount rates or underlying revenue forecasts would result in a higher or lower fair value measurement. For example, on June 26, 2026, the Company announced that the U.S. Food and Drug Administration (the “FDA”) issued a Complete Response Letter (“CRL”) regarding the New Drug Application (“NDA”) for LNTH-2501, stating that the FDA could not approve the NDA by the June 29, 2026 extended Prescription Drug User Fee Act target action date due to unresolved third-party facility manufacturing-related conditions. The Company included this information in its assessment of the probability of success attached to the contingent consideration for LNTH-2501 as of September 30, 2026. As a result of the assessment of all such changes, including settlements, the Company determined the value of the contingent consideration liabilities related to the acquisitions to be $68.2 million at September 30, 2026, $26.1 million less than the December 31, 2025 value of $94.3 million, net of settlements. The Company records the contingent consideration liabilities at fair value with changes in estimated fair values recorded within general and administrative expenses in its condensed consolidated statements of operations. The Company can give no assurance that the actual amounts paid, if any, in connection with the contingent consideration liabilities, will be consistent with any recurring fair value estimate of such contingent consideration liabilities.

The recurring Level 3 fair value measurements of the Company's contingent consideration liabilities include the following significant unobservable inputs (in thousands, except percent data):

Consideration Received From the Sale of the SPECT Business

On January 1, 2026, as a result of the sale of the Company’s SPECT business pursuant to the Equity and Asset Purchase Agreement, by and among Lantheus Medical, Lantheus MI Canada, Inc., Lantheus EU Limited, and Illuminated, SHINE SPECT, LLC, SHINE SPECT Medical Products, Ltd., and SHINE SPECT Limited (collectively referred to as “SHINE SPECT”), dated as of May 1, 2025 (the “SHINE SPECT Agreement”), the Company received consideration consisting of cash, notes receivable that may be settled in equity of Illuminated or in cash depending on their specific terms, a right to receive additional cash on the earlier of January 1, 2030 or upon the occurrence of certain specified events, and the right to certain contingent consideration, as described below.

Installment Note

The Company received the Installment Note from Illuminated on January 1, 2026. The Company estimated the fair value of the Installment Note issued on January 1, 2026 using a probability-weighted DCF model. The discount upon issuance of the Installment Note is being recognized into other income, net in the Company’s condensed consolidated statements of operations for the periods in which the instrument remains outstanding.

Illuminated completed a qualified financing in February 2026, resulting in the conversion of the Installment Note into Series E-1 Preferred on April 6, 2026 (the “Conversion Date”). On the Conversion Date and in accordance with the Installment Note, the Company entered into an Adoption Agreement with Illuminated pursuant to which the Company acquired 2,545,454 shares of Series E-1 Preferred upon the conversion in full and cancellation of the $70.0 million Installment Note at a conversion price of $27.50 per share. The Company estimated the fair value of the Series E-1 Preferred at $70.0 million based on the contemporaneous price paid by third-party investors for identical Series E-1 Preferred shares in Illuminated’s February 2026 qualified financing and in subsequent financings during the three months ended June 30, 2026. At the Conversion Date, the carrying value of the Installment Note was $70.0 million, with an unamortized discount of $2.5 million, and the fair value of the Series E-1 Preferred was $70.0 million, resulting in a $2.5 million gain on conversion of the Installment Note. The gain on conversion of the Installment Note is included in other income, net on the Company’s condensed consolidated statements of operations for the nine months ended September 30, 2026.

The Series E-1 Preferred is convertible, at any time upon the election of the holder, into shares of Illuminated common stock on a one-for-one-basis, votes on an as-converted basis alongside other shares of Illuminated’s preferred stock, and entitles the holders of the Series E-1 Preferred, voting as a single class along with the holders of all other shares of Series E convertible preferred stock, to elect one member to Illuminated’s board of directors, subject to certain minimum ownership thresholds. The Series E-1 Preferred are equity securities and within the scope of ASC 321,“Investments - Equity Securities.”The Company elected the measurement alternative for this investment in the Series E-1 Preferred because the shares do not have a readily determinable fair value and therefore are excluded from the assets and liabilities measured at fair value on a recurring basis table above. Under this alternative, the Company measures investments without readily determinable fair values at cost, less impairment, adjusted for changes from observable price changes in orderly transactions for identical or similar investments. As of September 30, 2026, the carrying value of the investment in Series E-1 Preferred was $70.0 million and is included in investment in equity securities on the Company’s condensed consolidated balance sheet.

Seller Note

The Company received an unsecured promissory note from SHINE SPECT (the “Seller Note”), with a principal amount of $20.0 million, an 8.0% annual interest rate payable semi-annually of which up to half can be paid in-kind, and a maturity date of the earlier of January 1, 2029 or completion of an initial public offering by Illuminated (“SHINE IPO”). The terms of the Seller Note are governed by a Subordination Agreement dated January 1, 2026, by and between Lantheus Medical, SHINE SPECT and other parties (the “Subordination Agreement”). Pursuant to the Seller Note, if a change in control or a material financing (each as defined in the Seller Note) occurs on or prior to the maturity date, the Company has the option to require a cash repayment equal to the outstanding principal amount of the Seller Note plus accrued interest, subject to the terms of the Subordination Agreement. In addition, SHINE SPECT has the option to prepay the Seller Note prior to the maturity date, subject to the Subordination Agreement. At issuance, the Company concluded that certain contingent repayment and acceleration features embedded within the Seller Note require separate accounting as an embedded derivative under ASC 815,“Derivatives and Hedging.” Accordingly, the Company recognized an immaterial derivative asset related to those features. The Company estimated the fair value of the Seller Note on January 1, 2026 using a DCF technique that incorporated probability-weighted repayment scenarios including scenarios involving the timing of payments. In connection with that analysis, the Company identified an immaterial embedded derivative that was bifurcated from the host debt contract. The carrying amount of the host debt instrument was determined after giving effect to the bifurcation of the embedded derivative. The resulting debt discount on the host debt-instrument is being accreted into other income, net in the Company’s condensed consolidated statements of operations over the period the Seller Note remains outstanding.

Deferred Cash Purchase Price

The Company will receive $20.0 million in cash on the earlier of (i) January 1, 2029 or (ii) a SHINE IPO (“Deferred Cash Purchase Price”). If the Deferred Cash Purchase Price is not paid by January 1, 2029, the Company will be entitled to an additional $5.0 million of cash consideration, for a total of $25.0 million in cash to be paid no later than January 1, 2030. The Company estimated the fair value of the Deferred Cash Purchase Price on January 1, 2026 using a probability-weighted DCF technique that incorporated various repayment timing scenarios, including the potential timing of a SHINE IPO. In connection with its accounting analysis of the Deferred Cash Purchase Price, the Company identified an immaterial derivative related to certain contingent repayment features and bifurcated those features from the host contract. The resulting discount on the host contract is being accreted into other income, net in the Company’s condensed consolidated statements of operations over the period in which the instrument remains outstanding.

Net Contingent Consideration

The Company may earn up to $30.0 million in a combination of cash and capital stock of Illuminated upon exceeding specified annual and cumulative revenue milestones of the SPECT business for each calendar year through December 31, 2027 (“Contingent Consideration Receivable”). The Company estimated the fair value of the Contingent Consideration Receivable on January 1, 2026 associated with the revenue annual and cumulative milestones using a Monte Carlo simulation in a risk-neutral framework, whereby the achievement of the future revenue associated with the sales milestones was simulated using a geometric Brownian motion model. The Company estimated the fair value of the Contingent Consideration Receivable to be $6.5 million on January 1, 2026.

A contingent consideration payable of $1.4 million for the 2025 fiscal year was payable by the Company pursuant to terms of the SHINE SPECT Agreement, and settled shortly after January 1, 2026, and was included in the computation of the net consideration received.

All components of net consideration received were measured at fair value on January 1, 2026 in computing the gain on sale of business. The fair value of total net consideration received by the Company was approximately $131.2 million, including $32.1 million in cash, as well as other instruments as follows:

(1)

This amount includes a net working capital settlement of $0.7 million received on July 1, 2026.

5. Income Taxes

The Company calculates income taxes at the end of each reporting period based on the estimated effective tax rate for the full year, adjusted for any discrete events which are recorded in the period they occur. Cumulative adjustments to the tax provision are recorded in the reporting period in which a change in the estimated annual effective tax rate is determined. The Company’s income tax expense and effective tax rate are presented below:

The Company’s effective tax rate for the three months ended September 30, 2026 differs from the U.S. statutory rate of 21% primarily due to a partial release of the valuation allowance related to losses on its investment in equity securities, partially offset by the non-deductible change in fair value of contingent consideration and non-deductible milestone payments.

The Company’s effective tax rate for the nine months ended September 30, 2026 differs from the U.S. statutory rate of 21% primarily due to a partial release of the valuation allowance related to losses on its investment in equity securities and the non-taxable change in fair value of contingent consideration, partially offset by state income taxes.

6. Inventory, Net

Inventory, net of related reserves, consisted of the following:

The majority of the value of the inventory relates to non-radioactive products. With respect to the Company’s products that are radiopharmaceuticals, due to the limited shelf life of such products, they are generally not held as finished goods.

7. Property, Plant and Equipment, Net

Property, plant and equipment, net, consisted of the following:

Depreciation and amortization expense related to property, plant and equipment, net, was $6.1 million and $5.6 million for thethree months ended September 30, 2026 and 2025, respectively, and $17.9 million and $16.3 million for thenine months ended September 30, 2026 and 2025, respectively.

8. SPECT Business

Sale of SPECT Business

On January 1, 2026 (the “Disposition Date”), the Company completed the sale of its SPECT business to SHINE SPECT (the “Disposition”). Upon completion of the Disposition, the Company did not retain an equity interest in the SPECT entities sold in connection with the Disposition and concluded that it no longer held a controlling financial interest in the SPECT business. Accordingly, all previously recognized assets and liabilities of the SPECT business that were conveyed to SHINE SPECT were deconsolidated. Assets and liabilities derecognized upon the Disposition included those relating to the Company’s approved SPECT products (TechneLite, NEUROLITE, Xenon Xe-133 Gas, and Cardiolite), the portion of the North Billerica, Massachusetts campus that manufactures the SPECT products and specified assets and liabilities of the Company’s Canada-based SPECT operations. The Company has concluded that following the Disposition, SHINE SPECT and the Company are not related parties.

Consideration received from SHINE SPECT on the Disposition Date consisted of cash, the Installment Note, the Seller Note, the Deferred Cash Purchase Price and the right to certain contingent consideration. All components of consideration received were measured at fair value on the Disposition Date in computing the loss (gain) on sale of business, net of transaction costs. The fair value of total net consideration received on the Disposition Date was approximately $131.2 million. See Note 4,“Fair Value of Financial Instruments”for more information on the total net consideration received for the Disposition.

The Company recognized a gain on sale of the SPECT business of$59.4 million, net of transaction costs, for the nine months ended September 30, 2026, including a $0.1 million loss, which was an adjustment recorded during the three months ended September 30, 2026 for a true-up of assets. The Company recorded a post-closing working capital settlement related to the sale of its SPECT business which was partially offset by miscellaneous asset and liability true-ups recorded during the nine months ended September 30, 2026. In addition, the nine-month period ended September 30, 2026 includes the Disposition Date fair value of consideration received of $131.2 million, including a $0.7 million net working capital settlement received in July 2026, less the carrying value of the deconsolidated assets and liabilities of approximately $64.5 million, and is net of transaction costs incurred and paid by the Company of $7.2 million during the first quarter of 2026 and a $0.1 million loss, which was an adjustment recorded during the third quarter of 2026 for the true-up of assets. This gain on sale of business, net of transaction costs is presented within non-operating income on the Company’s condensed consolidated statements of operations for the nine months ended September 30, 2026.

Assets and Liabilities Held for Sale

As of December 31, 2025, assets and liabilities associated with the Company’s SPECT business were presented in the Company’s consolidated balance sheet as assets and liabilities held for sale since it was determined that those assets and liabilities met the criteria of held-for-sale under ASC 360,“Impairment or disposal of long-lived assets.”

The Company does not believe the sale represented a strategic shift that had a major effect on the Company's consolidated financial results and therefore did not meet the criteria for classification as discontinued operations.

The table below presents the estimated carrying amounts of assets and liabilities held for sale related to the SPECT business as of December 31, 2025:

9. Accrued Expenses, and Other Current and Long-Term Liabilities

Accrued expenses, and other current and long-term liabilities are comprised of the following:

10. Goodwill and Intangibles, Net

Goodwill

The following table represents the change in the carrying value of goodwill for thenine months ended September 30, 2026:

Intangibles, net, consisted of the following:

During the third quarter of 2026, the Company identified an impairment triggering event on its LNTH-2620 (previously referred to as PI-2620) and LNTH-2515 in-process research and development (“IPR&D”) intangible assets, and after completing the quantitative impairment test, recognized impairment charges of $21.0 million and $10.0 million, respectively. LNTH-2620 and LNTH-2515 were acquired in July 2025 with the acquisition of Lantheus Biosciences and had initial fair values of $21.0 million and $13.0 million, respectively, based on expected future cash flows on the date of acquisition. The impairment charges for LNTH-2620 and LNTH-2515 are included in research and development (“R&D”) expenses in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026.

On August 14, 2026, the Company announced that the FDA approved TAUKLARIFY (florquinitau F-18 injection), also referred to as MK-6240. As a result, the Company reassessed the existing development plan for LNTH-2620 and because there is no near-term plan to commercialize the asset, the Company determined that based on the updated analysis of the future cash flow, the value of the asset that remained was immaterial and therefore the Company recorded the full impairment in an amount equal to $21.0 million for the three and nine months ended September 30, 2026.

During the third quarter of 2026, the Company performed an updated analysis of the future cash flows of LNTH-2515 and as a result, recognized an impairment charge of $10.0 million during the three and nine months ended September 30, 2026.

The estimate of future cash flows used in impairment testing involves significant management judgment, and is based upon assumptions about expected future operating performance, economic conditions, market conditions and cost of capital. Inherent in estimating the future cash flows are uncertainties beyond our control, such as changes in capital markets. The actual cash flows could differ materially from management’s estimates due to changes in business conditions.

The Company recorded amortization expense for its intangible assets of $16.7 million and $14.6 million for thethree months ended September 30, 2026 and 2025, respectively, and $50.2 million and $30.6 million for thenine months ended September 30, 2026 and 2025, respectively.

The table below summarizes the estimated aggregate amortization expense expected to be recognized on the above intangible assets:

11. Long-Term Debt, and Other Borrowings, Net of Current Portion

The carrying value of the Company’s long-term debt and other borrowings, net of current portion is comprised of the following:

2022 Revolving Facility

In December 2024, the Company entered into an amendment to its $350.0 million five-year revolving credit facility originally entered into in December 2022. The amendment, among other things, increased the facility from $350.0 million to $750.0 million (as amended, the “2022 Revolving Facility”) and extended the maturity date from December 2, 2027 to December 19, 2029. Under the terms of the 2022 Revolving Facility, the lenders are committed to extending credit to the Company from time to time consisting of revolving loans (the “Revolving Loans”) in an aggregate principal amount not to exceed $750.0 million (the “Revolving Commitment”) at any time, including a $40.0 million sub-facility for the issuance of letters of credit (the “Letters of Credit”) and a $20.0 million sub-facility for swingline loans (the “Swingline Loans”). The Revolving Loans, Letters of Credit, and the Swingline Loans, if used, are expected to be used for working capital and for other general corporate purposes.

The Revolving Loans bear interest, with pricing based from time to time at the Company’s election, at (i) the secured overnight financing rate as published by the Federal Reserve Bank of New York on its website plus an applicable margin that ranges from 1.25% to 2.00% based on the Company’s total net leverage ratio or (ii) the alternative base rate plus an applicable margin that ranges from 0.25% to 1.00%, in either case, based on the Company’s total net leverage ratio. The 2022 Revolving Facility also includes an unused commitment fee at a rate ranging from 0.15% to 0.30% per annum based on the Company’s total net leverage ratio. Interest associated with the unused commitment is recorded to accrued expenses and other current and long-term liabilities on the condensed consolidated balance sheets and paid out on a quarterly basis.

The Company is permitted to voluntarily prepay the Revolving Loans, in whole or in part, or reduce or terminate the Revolving Commitment, in each case, without premium or penalty. On any business day on which the total amount of outstanding Revolving Loans, Letters of Credit, and Swingline Loans exceeds the total Revolving Commitment, the Company must prepay the Revolving Loans in an amount equal to such excess. The Company is not required to make mandatory prepayments under the 2022 Revolving Facility. As of September 30, 2026, there wereno outstanding borrowings under the 2022 Revolving Facility.

The Company has the right to request an increase to the Revolving Commitment in an aggregate principal amount of up to the greater of $685.0 million (so that the total amount available would be approximately $1.44 billion)or 100% of consolidated earnings before interest, taxes, depreciation and amortization for the four consecutive fiscal quarters most recently ended, plus additional amounts in certain circumstances (collectively, the “Incremental Cap”), minus certain incremental term loans made pursuant to specified incremental term loan commitments (“Incremental Term Loans”). The Company has the right to request Incremental Term Loans in an aggregate principal amount of up to the Incremental Cap less any incremental increases to the Revolving Commitment. Proceeds of Incremental Term Loans may be used for working capitaland for other general corporate purposes and will bear interest at rates agreed between the Company and the lenders providing the Incremental Term Loans.

2022 Revolving Facility Covenants

The 2022 Revolving Facility contains a number of affirmative, negative and reporting covenants, as well as financial maintenance covenants pursuant to which the Company is required to be in quarterly compliance, measured on a trailing four quarter basis, withtwo financial covenants. The minimum interest coverage ratio must be at least 3.00 to 1.00. The maximum total net leverage ratio permitted by the financial covenant is 3.50 to 1.00, other than in connection with certain acquisitions, in which case, the maximum total net leverage ratio permitted can be increased to 4.00 to 1.00.

The 2022 Revolving Facility contains usual and customary restrictions on the ability of the Company and its subsidiaries to: (i) incur additional indebtedness (ii) create liens; (iii) consolidate, merge, sell or otherwise dispose of all or substantially all of its assets; (iv) sell certain assets; (v) pay dividends on, repurchase or make distributions in respect of capital stock or make other restricted payments; (vi) make certain investments; (vii) repay subordinated indebtedness prior to stated maturity; and (viii) enter into certain transactions with its affiliates.

Upon an event of default, the Administrative Agent (as defined in the 2022 Revolving Facility) will have the right to declare the loans and other obligations outstanding under the 2022 Revolving Facility immediately due and payable and all commitments immediately terminated.

The 2022 Revolving Facility is guaranteed by Lantheus Holdings, and certain subsidiaries of Lantheus Medical, including Progenics and Lantheus Real Estate, and obligations under the 2022 Revolving Facility are generally secured by first priority liens over substantially all of the assets of each of Lantheus Medical, Lantheus Holdings, and certain subsidiaries of Lantheus Medical, including Progenics and Lantheus Real Estate (subject to customary exclusions set forth in the transaction documents) owned as of December 2, 2022 or thereafter acquired.

2.625% Convertible Senior Notes due December 2027

On December 8, 2022, the Company issued $575.0 million in aggregate principal amount of 2.625% Convertible Senior Notes due December 2027 (the “Notes”), which includes $75.0 million in aggregate principal amount of Notes sold pursuant to the full exercise of the initial purchasers’ option to purchase additional Notes. The Notes were issued under an indenture, dated as of December 8, 2022 (the “Indenture”), among the Company, Lantheus Medical, a wholly owned subsidiary of the Company, as Guarantor, and U.S. Bank Trust Company, National Association, as Trustee. The net proceeds from the issuance of the Notes were approximately $557.8 million after deducting the initial purchasers’ discounts and offering expenses payable by the Company.

The Notes are senior unsecured obligations of the Company. The Notes are fully and unconditionally guaranteed on a senior unsecured basis by the Guarantor. The Notes bear interest at a rate of 2.625% per year, payable semi-annually in arrears on June 15 and December 15 of each year, beginning on June 15, 2023, and will mature on December 15, 2027 unless earlier redeemed, repurchased or converted in accordance with their terms. The initial conversion rate for the Notes is 12.5291 shares of the Company’s common stock per $1,000 in principal amount of Notes (which is equivalent to an initial conversion price of approximately $79.81 per share of the Company’s common stock (the “Conversion Price”), representing an initial conversion premium of approximately 42.5% above the closing price of $56.01 per share of the Company’s common stock on December 5, 2022). In no event shall the conversion rate per $1,000 in principal amount of the Notes exceed 17.8539 shares of the Company’s common stock. Prior to the close of business on the business day immediately preceding September 15, 2027, the Notes may be converted at the option of the holders only upon occurrence of specified events and during certain periods, and thereafter until the close of business on the business day immediately preceding the maturity date, the Notes may be converted at any time. The Company will satisfy any conversion by paying cash up to the aggregate principal amount of the Notes to be converted and by paying or delivering, as the case may be, cash, shares of the Company’s common stock, or a combination of cash and shares of the Company’s common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted. The Company may redeem for cash all or any portion of the Notes, at its option if the closing sale price per share of the Company’s common stock exceeds 130% of the Conversion Price of the Notes for at least 20 trading days of the last 30 consecutive trading days of the quarter. The redemption price will be equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date.

The Company evaluated the Notes upon completion of the sale and concluded on the following features:

•

Conversion Feature: The Company determined that the conversion feature qualifies for the classification of equity. As a result, the conversion feature should not be bifurcated as a derivative instrument and the Notes were accounted for as a single liability.

•

Redemption Features: The redemption features were reviewed within the Notes and the Company determined that the redemption features are closely related to the Notes and as such should not be separately accounted for as a bifurcated derivative instrument.

•

Additional Interest Features: The Notes may result in additional interest if the Company fails to timely file any document or report that the Company is required to file with the SEC pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The Company will pay additional interest on the Notes at a rate equal to 0.25% to 0.50% per annum based on the principal amount of Notes outstanding for each day the Company’s failure to file has occurred or the Notes are not otherwise freely tradable. Further, if the Notes are assigned a restricted CUSIP number or the Notes are not otherwise freely tradable pursuant to Rule 144 under the Securities Act of 1933, as amended, by holders other than Company affiliates or holders that were Company affiliates at any time during the three months immediately preceding as of the 385 th day after the last date of original issuance of the Notes, the Company will pay additional interest on the Notes at a rate equal to 0.25% to 0.50% per annum based on the principal amount of Notes outstanding for each day until the restrictive legend has been removed from the Notes, the Notes are assigned an unrestricted CUSIP and the Notes are freely tradable. The Company concluded that the interest feature is unrelated to the credit risk and should be bifurcated from the Notes, however, the Company assessed the probabilities of triggering events occurring under these features and does not expect to trigger the aforementioned events. These events will continue to be monitored to determine whether the interest feature will be bifurcated if it has value.

Holders of the Notes may require the Company to repurchase their Notes upon the occurrence of a fundamental change prior to the maturity at a repurchase price equal to 100% of the principal amount thereof, plus accrued and unpaid interest to, but excluding, the date of repurchase. In connection with certain triggering events, the Company will, under certain circumstances, increase the conversion rate for holders of the Notes who elect to convert their Notes in connection with such corporate events.

Holders of the Notes may elect to convert their Notes during a calendar quarter if the trading price of the Company’s common stock was greater than or equal to 130% of the Conversion Price of the Notes (or $103.75 per share) for at least 20 trading days of the last 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter (the “Stock Price Conversion Threshold”). During the third quarter of 2026, the closing price of the Company’s common stock did not exceed the Stock Price Conversion Threshold. As a result, the Notes are not convertible at the option of the holders of the Notes during the fourth quarter of 2026. Because the Notes are not considered convertible under the terms of the Notes and pursuant to ASC 470-10, the Company classified the carrying value of the Notes as long-term debt and other borrowings on the Company’s condensed consolidated balance sheets as of September 30, 2026.

As of September 30, 2026, the carrying value of the Notes was $575.0 million, the Notes had an unamortized discount of $4.2 million, and the fair value of the liability was $739.4 million. The Company recorded interest expense of approximately $3.8 million and $11.3 million related to the Notes for the three and nine months ended September 30, 2026, respectively.

12. Stockholders' Equity and Stock-Based Compensation

Equity Incentive Plan

On April 30, 2026, the Company’s stockholders approved the Amended and Restated 2026 Equity Incentive Plan (the “2026 Plan”) which amended and restated the 2015 Equity Incentive Plan to (i) increase the number of shares of common stock reserved for issuance thereunder by 2,000,000 shares, (ii) effect the name change of the 2026 Plan, (iii) change the provision regarding non-employee director compensation limits from a number of shares of common stock not to exceed 500,000 shares to total compensation of (a) no more than $1,250,000 in combined cash and equity awards during such director’s year of appointment and (b) no more than $750,000 in combined cash and equity awards in any other year of service, and (iv) remove and revise certain provisions that were otherwise required for awards to qualify as performance-based compensation under Section 162(m) of the Internal Revenue Code of 1986, as amended, prior to the repeal of the applicable limitations thereunder. The 2026 Plan is administered by the Board of Directors (the “Board”) and permits the granting of stock, stock options, stock appreciation rights, restricted stock, restricted stock units and dividend equivalent rights to employees, officers, directors and consultants of the Company. As of September 30, 2026, the aggregate shares of common stock reserved for issuance under the 2026 Plan, as amended, is 16,930,277 shares.

Common Stock Repurchases

On July 31, 2025, the Board authorized a program to repurchase up to $400.0 million of shares of the Company’s common stock through December 31, 2027 (the “2025 Program”). During the three and nine months ended September 30, 2026, the Company didnot repurchase any of its common stock under the 2025 Program. During 2025, the Company repurchased a total of 3.5 million shares for an aggregate purchase price of approximately $200.0 million under the 2025 Program for an average stock price of $56.72. A total of approximately $200.0 million of shares of the Company’s common stock remain available for repurchase under the 2025 Program as of September 30, 2026.

Employee Stock Purchase Plan

Effective September 11, 2026, the Lantheus Holdings, Inc. 2023 Employee Stock Purchase Plan (the “2023 ESPP”) was suspended after the completion of the current offering period. The 2023 ESPP provided for the granting of up to 500,000 shares of the Company’s common stock to eligible employees. The 2023 ESPP allowed eligible employees to contribute up to 15% of their qualifying compensation toward the semi-annual purchase of the Company’s common stock in March and September of each year, subject to an annual maximum dollar amount. The purchase price was the lesser of 85% of the fair market value of the stock on the last trading day of each Offering Period (as defined in the 2023 ESPP); or the first trading day of each Offering Period. In March 2026 and September 2026, the Company issued 58,907 shares and 31,956 shares under the 2023 ESPP, respectively. As of September 30, 2026, the number of shares that would have been available for issuance under the 2023 ESPP if the suspension was not in place was 308,437 shares. The Company calculated the fair value of the shares issued under the 2023 ESPP using the Black-Scholes model at the commencement of an Offering Period in March and September of each year and the related expense is recorded over the Offering Period. Shares issuable under the Offering Period ending September 11, 2026 were issued in accordance with the 2023 ESPP, and no additional Offering Period commenced thereafter.

Stock-Based Compensation Expense

The following table presents stock-based compensation expense recognized in the Company’s accompanying condensed consolidated statements of operations:

13. Net Income Per Common Share

A summary of net income per common share is presented below:

Impact of the Convertible Notes

The Company considers shares issuable upon conversion of the Notes to be common stock equivalents and are only included in the calculation of diluted net income per share when their effect is dilutive. The Company has the option to settle the Notes through cash settlement or a combination of cash and share settlement provided that the principal is settled in cash and the conversion spread is settled in cash or shares as elected by the Company. The Company considers the Notes to be participating securities through the two-class method. Per the terms of the Indenture, the Company determined that if a cash dividend is paid that is greater than the stock price at the time such dividend is declared, the holders of the Notes will receive cash on an if-converted basis. While this feature is considered to be a participating right, basic income attributable to common stockholders is only impacted if the Company’s earnings per share exceeds the current share price, regardless of whether such dividend is declared. During the three and nine months ended September 30, 2026 and 2025, no such dividend was declared, and the Company’s earnings per share did not exceed its share price. The Company is required to settle the principal amount of the Notes in cash upon conversion, and convertibility of the Notes is dependent upon the Company’s share price. Therefore, the Company used the if-converted method for calculating the dilutive effect of the conversion option on diluted net income per share. The conversion option will have a dilutive impact on net income per share of common stock when the average price per share of the Company's common stock for a given period exceeds the Conversion Price of the Notes. See Note 11,“Long-Term Debt, and Other Borrowings, Net of Current Portion” for further discussion on the Notes.

14. Other Income

Other income consisted of the following:

(1)

In 2025, the Company revised certain inputs to its estimate of decommissioning costs expected to be incurred throughout the period of remediation, which reduced the estimate of remediation costs at the time by $4.7 million. See Note 9,“Asset Retirement Obligations” included in the Company’s Form 10-K for the year ended December 31, 2025 for more information.

(2)

In April 2026, the Company converted the $70.0 million Installment Note received upon the sale of its SPECT business into the Series E-1 Preferred. Upon conversion, the Company recognized a gain on conversion of $2.5 million. See Note 4, “Fair Value of Financial Instruments,”above for more information.

15. Commitments and Contingencies

Legal Proceedings

From time to time, the Company is a party to various legal proceedings arising in the ordinary course of business. In addition, the Company has in the past been, and may in the future be, subject to investigations by governmental and regulatory authorities, which expose it to greater risks associated with litigation, regulatory or other proceedings, as a result of which the Company could be required to pay significant fines or penalties. The costs and outcome of litigation, regulatory or other proceedings cannot be predicted with certainty, and some lawsuits, claims, actions or proceedings may be disposed of unfavorably to the Company and could have a material adverse effect on the Company’s business, financial condition, results of operations and cash flows. In addition, intellectual property disputes often have a risk of injunctive relief which, if imposed against the Company, could materially and adversely affect its financial condition or results of operations. If a matter is both probable to result in material liability and the amount of loss can be reasonably estimated, the Company estimates and discloses the possible material loss or range of loss. If such loss is not probable or cannot be reasonably estimated, a liability is not recorded in its condensed consolidated financial statements.

On January 26, 2024, the Company was sued in the United States District Court for the District of Delaware (the “District Court”) by Advanced Accelerator Applications USA, Inc. and Advanced Accelerator Applications SA (collectively known as “ADACAP” in the court proceedings), each a Novartis entity, for patent infringement in response to the filing of the Company’s Abbreviated New Drug Application (“ANDA”) and Paragraph IV certification in connection with PNT2003, consistent with the process established by the Hatch-Waxman Act. In December 2025, the court conducted its trial. On June 17, 2026, the District Court issued an opinion in Lantheus’s favor; specifically, the District Court determined that all the patents asserted by ADACAP are invalid. On June 23, 2026, ADACAP appealed the District Court’s decision to the Court of Appeals for the Federal Circuit (“CAFC”) and moved for an emergency injunction to stay Lantheus’s launch of PNT2003 pending appeal. On July 2, 2026, the CAFC denied ADACAP’s motion to stay Lantheus from launching PNT2003 during the appeal process. As of the date of this Form 10-Q, the Company has received final FDA approval for PNT2003, now referred to as BRAVNETSA (lutetium Lu 177 dotatate), and is participating in the appeal briefing process on an expedited basis which will culminate in an oral hearing before the CAFC currently scheduled for December 14, 2026. The timing of the final decision of the CAFC on ADACAP’s appeal is not known. Because the outcome of litigation is uncertain, the Company cannot predict how or when this matter will ultimately be resolved.

On September 9, 2025, an alleged stockholder initiated a putative securities class action against the Company in the United States District Court for the Southern District of New York, styled Margolis v. Lantheus Holdings, Inc., et al. The operative complaint also asserts claims against certain of the Company’s named executives. A related action, styled Indiana Pub. Ret. Sys. v. Lantheus Holdings, Inc., et al., was filed in the same court on November 5, 2025. Those actions are now consolidated into a single putative securities class action (captioned In re Lantheus Holdings, Inc. Secs. Litig.), the theory of which is that the defendants made materially false or misleading statements (or omitted material facts) in violation of the Exchange Act. The lead plaintiff filed an amended complaint on March 13, 2026. The Company and its executives filed a motion to dismiss the amended complaint on May 11, 2026, and under the operative scheduling order, that motion was fully briefed by August 10, 2026. Additionally, on December 17, 2025, another alleged stockholder of the Company filed a shareholder derivative action in the same court, styled Lelchuk v. Heino et al., nominally on behalf of the Company and naming as defendants the current directors of the Board and the same officers named in the consolidated securities class action described above (a similar derivative complaint styled Jones v. Markison et al., was previously filed on October 31, 2025 but was voluntarily withdrawn without prejudice). The derivative complaint largely repeats the allegations asserted in the consolidated securities class action, and asserts claims for alleged breaches of fiduciary duties, aiding and abetting breach of fiduciary duty, unjust enrichment, waste of corporate assets, and violations of the Exchange Act. The plaintiff seeks damages and other relief on behalf of the Company. The derivative action is stayed pending one or more of the following events: (i) a public announcement of any settlement of the putative securities class action; (ii) a ruling on the defendants’ motion to dismiss; or (iii) a dismissal with prejudice of the putative securities class action and exhaustion of all related appeals. Because the outcome of litigation is uncertain, the Company cannot predict how or when these matters will ultimately be resolved.

Following the filing on September 8, 2026 of the Company’s definitive proxy statement (the “Definitive Proxy Statement”) relating to the Merger (as defined below), three complaints were filed by purported stockholders against the Company and certain members of the Board in connection with the Merger. Two such complaints were filed in the Supreme Court of the State of New York, County of New York: Hamilton v. Lantheus Holdings, Inc., et al., Index No. 655291/2026, filed on September 16, 2026, and McDaniels v. Lantheus Holdings, Inc., et al., Index No. 655281/2026, filed on September 16, 2026, and one was filed in the Superior Court of the Commonwealth of Massachusetts, Middlesex County: Garfield v. Lantheus Holdings, Inc., et al., Civil Docket No. 2681CV02581, filed on September 25, 2026 (collectively, the “Merger Complaints”). The Merger Complaints generally alleged, among other things, that the Definitive Proxy Statement omitted or misrepresented certain material information and asserted claims under state common law.

In addition to the Merger Complaints, the Company has received sixteen demand letters from purported stockholders of the Company, two of which attached a draft complaint, making similar allegations to the Merger Complaints (the “Demand Letters”).

On October 2, 2026, solely to avoid the costs, burden, nuisance and uncertainties inherent in litigation and without admitting any liability or wrongdoing, the Company filed supplemental disclosures to the Definitive Proxy Statement. On October 14, 2026, the Company’s stockholders adopted the Merger Agreement (as defined below) and approved related proposals at a special meeting of stockholders. The Company believes the Merger Complaints and the Demand Letters are without merit. Additional demand letters or lawsuits may be received or filed in connection with the Merger. Because the outcome of litigation is uncertain, the Company cannot predict how or when these matters will ultimately be resolved.

As of September 30, 2026, the Company was not a party to any other material ongoing legal proceedings and has determined that the aforementioned matters are not expected to have a material adverse effect on its business or consolidated financial results.

Technology License and Other Commitments

The Company has licensed from third parties the rights to use certain technologies in its R&D processes as well as in other products it may develop, commercialize, or sell. In accordance with the related license or sublicense agreements, the Company is contractually required to make certain future payments to these third parties contingent upon (i) the achievement of specified regulatory, development and/or commercialization milestones and (ii) future sales of specified products in the form of royalty payments. Milestone payments are generally recognized in the period in which the achievement of the underlying milestone becomes probable, which is generally the period in which it is actually achieved. Royalty payments are generally recognized in the period in which the associated revenue is recognized.

Repurchase of License

In June 2026, the Company entered into a repurchase agreement (the “Repurchase Agreement”) with its distributor in China pursuant to which the Company repurchased from the distributor the license to DEFINITY in China along with the related materials, approvals and clinical trial research that had been accumulated since the original Distribution and Supply Agreement between the same parties (the “Supply Agreement”), which was executed in April 2012. The Company’s repurchase right was in accordance with the Supply Agreement. The total consideration to be paid as part of the Repurchase Agreement is $30.0 million. The Company paid $15.0 million of this consideration during the three months ended September 30, 2026. The remaining $15.0 million is expected to be paid in two tranches by the end of 2026 upon satisfaction of certain conditions, is recorded as an obligation in accrued expenses and other current liabilities on the Company’s condensed consolidated balance sheet as of September 30, 2026 and was fully expensed to sales and marketing expenses on the Company’s condensed consolidated statements of operations during the second quarter of 2026.

16. Benefit Plans

Nonqualified Deferred Compensation Plan

In October 2024, the Company adopted the LDCP to provide key, highly-compensated employees and non-employee directors an additional opportunity for personal financial planning by allowing an option to defer a portion of their base salary and variable compensation each year. Under the LDCP, which is an elective nonqualified deferred compensation plan, employee participants are eligible to defer up to 80% of base salary and up to 80% of any bonus award beginning in 2025. Non-employee directors that are participants of the LDCP are eligible to defer up to 100% of their Board fees. Additionally, Company matching or employer contributions may be credited to the LDCP. Any matching or employer contributions cliff vest after the earlier of (i)five years, (ii) the participant reaching age 55, (iii) death, or (iv) disability. All amounts deferred or credited to a participant’s account (the “Deferred Amounts”) are held in a separate trust which was established by the Company to administer the LDCP. The LDCP assets held in trust by the Company to offset its obligation, which could currently consist of COLI and mutual funds, are subject to the claims of the Company’s creditors in the event that the Company becomes insolvent. Consequently, the trust qualifies as a grantor trust for income tax purposes, or a Rabbi Trust (the “Trust”). Amounts deferred (and earnings on those amounts) are generally distributed following termination of employment unless the participant has elected an earlier distribution date, which may be no earlier than January 1st of the second year following the year of deferral. Vested Company matching or employer contributions (and earnings on those amounts) are generally distributed following termination of employment. Participants can elect to receive distributions in a lump sum, in annual installments over a period of not more than ten years for a qualifying distribution event (as defined in the LDCP), or in annual installments over a period of not more than five years if distributions are made prior to termination of employment.

As of September 30, 2026, assets and liabilities held by the Trust were $2.1 million and $1.9 million, respectively. As of December 31, 2025, assets and liabilities held by the Trust were $1.1 million and $0.9 million, respectively. Assets and liabilities held by the Trust as of each such date were included in other long-term assets, accrued expenses and other current and long-term liabilities in the Company’s condensed consolidated balance sheets. Changes in the value of the LDCP assets and liabilities are charged to net loss (gain) on investment in equity securities and to general and administrative expenses, respectively, in the Company’s condensed consolidated statements of operations and were de minimis for the three and nine months ended September 30, 2026.

17. Proposed Merger

Pending Merger with Curium US Holdings LLC

On August 3, 2026, the Company entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Curium US Holdings LLC (the “Parent”), and Coco Merger Sub Inc. (the “Merger Sub”), pursuant to which, subject to the terms and conditions set forth therein, the Parent will acquire the Company by means of a statutory merger of the Merger Sub with and into the Company, with the Company surviving as the Parent’s wholly-owned subsidiary (the “Merger”).

Upon the terms and subject to the conditions set forth in the Merger Agreement, the Parent will acquire all of the outstanding shares of the Company’s common stock (other than certain excluded shares and shares for which appraisal rights have been properly exercised) for $102.50 per share in cash at the effective time of the Merger. In addition, the Company’s stockholders will receive one contingent value right (“CVR”) per share representing the right to receive up to $12.00 per share in cash upon the achievement of certain specified commercial milestones, all subject to the terms and conditions set forth in a CVR agreement to be entered into between the Parent and a rights agent selected by the Parent and reasonably acceptable to the Company. The Merger is currently expected to close in the first half of 2027, subject to the satisfaction or waiver of customary closing conditions, including required regulatory approvals. If the Merger is consummated, the Company’s common stock will be delisted from the Nasdaq Global Market and deregistered under the Exchange Act.

The Company has also agreed not to (i) initiate, solicit or knowingly facilitate or knowingly encourage the making of any proposal or offer that constitutes or would reasonably be expected to lead to, a Competing Proposal (as defined in the Merger Agreement), (ii) engage in, continue or otherwise participate in any discussions or negotiations regarding, or furnish to any person (other than the Parent or its representatives) any non-public information in connection with or for the purpose of knowingly facilitating or knowingly encouraging, a Competing Proposal or (iii) enter into any letter of intent, acquisition agreement, agreement in principle or similar agreement with respect to a Competing Proposal.

The consummation of the Merger is subject to the fulfillment or waiver of certain customary mutual closing conditions, including, among other things, (a) that no law or governmental order, injunction, decree or decision preventing the consummation of the Merger is in effect and no statute, rule or regulation shall have been enacted, entered, promulgated or enforced, and still be in effect, that prohibits or makes illegal consummation of the Merger and (b) that any waiting period (or any extension thereof) applicable to the Merger and the other transactions under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”) have terminated or expired and all other scheduled antitrust or investment screening law approvals having been obtained. The obligation of each party to consummate the Merger is also conditioned upon the accuracy of the other party’s representations and warranties (subject in certain cases to customary materiality qualifications) and the other party’s performance or compliance in all material respects with its obligations under the Merger Agreement, and the obligation of the Parent and Merger Sub is also conditioned upon there being no Company Material Adverse Effect (as defined in the Merger Agreement) having occurred that is continuing at the effective time of the Merger. The consummation of the Merger is not subject to any financing condition.

The Merger Agreement contains certain termination rights for each of the Company and the Parent, including, among others, the right of either party to terminate if the Merger is not consummated on or before 11:59 p.m. Eastern Time on May 2, 2027 (the “Outside Date”), subject to extension in certain circumstances (provided that the Outside Date shall not be extended beyond November 30, 2027), and the right of the Company, in certain circumstances, to terminate the Merger Agreement and accept a Superior Proposal. The Company will be required to pay the Parent a termination fee of $228.0 million in cash if the Merger Agreement is terminated (a) by the Parent because, prior to receipt of the requisite approval by the Company’s stockholders, the Board or any committee thereof makes a change to its recommendation of the Merger, (b) by the Company in order to enter into an alternative acquisition agreement with respect to a Superior Proposal or (c)(i)(A) by the Parent or the Company pursuant to the Outside Date termination right, (B) by the Parent or the Company because the Company stockholder approval was not obtained, or (C) by the Parent because of a willful breach of the Merger Agreement by the Company, and (ii) a bona fide Competing Proposal (as defined and so modified in the Merger Agreement) was publicly disclosed after the date of the Merger Agreement and prior to such termination and was not publicly withdrawn prior to such termination, and (iii) within 12 months after such termination, the Company enters into an alternative acquisition agreement with respect to such Competing Proposal (and such transaction is subsequently consummated) or consummates such a transaction. In no event will the Company be required to pay such termination fee more than once. The Parent will be required to pay the Company a general termination fee of $385.0 million or, alternatively, a regulatory termination fee of $100.0 million, in each case under specified circumstances, including, in the case of the regulatory termination fee, the termination of the Merger Agreement due to the failure to consummate the Merger by the Outside Date as a result of the failure to obtain certain required regulatory approvals or due to a final and non-appealable injunction or order relating to antitrust laws or foreign direct investment laws. In no event will Parent be required to pay both fees.

The Company incurred approximately $18.6 million in costs during the three and nine months ended September 30, 2026, consisting primarily of legal and other advisor costs related to the proposed Merger, which are included in general and administrative expenses in the Company’s condensed consolidated statements of operations.

For additional information regarding the Merger Agreement and the proposed Merger please see the Company’s Current Report on Form 8-K filed with the SEC on August 4, 2026 and Definitive Proxy Statement. A special meeting of the Company’s stockholders was held on October 14, 2026, at which, among other items, the Merger Agreement was adopted. See Note 20, “Subsequent Event”for more information on the results of the stockholders’ vote and the status of required regulatory approvals.

18. Acquisitions

Acquisition of Businesses

Evergreen Theragnostics, Inc.

On April 1, 2025 (the “Evergreen Closing Date”), the Company acquired all the issued and outstanding shares of Evergreen by means of a statutory merger of a subsidiary of the Company with and into Evergreen, with Evergreen surviving as the Company’s wholly-owned subsidiary (the “Evergreen Acquisition”), pursuant to the terms of the Evergreen Merger Agreement. Evergreen is a clinical-stage radiopharmaceutical company engaged in contract development and manufacturing organization services as well as drug discovery and commercialization of proprietary products.

As consideration for the Evergreen Acquisition, the Company made an upfront payment of $276.4 million in cash. The upfront cash consideration included a $25.0 million milestone payment that was triggered prior to the Evergreen Closing Date, the cash settlement of the options and restricted stock units granted to certain Evergreen equity holders related to pre-acquisition services, which was recorded as a component of consideration transferred of $6.1 million, the settlement by the Company of the pre-existing Evergreen debt of $4.3 million, and the payment of transaction expenses paid by the Company on behalf of Evergreen of $11.6 million. In connection with the Evergreen Acquisition, certain equity awards that were outstanding and unvested prior to the acquisition became fully vested per the terms of the

Evergreen Merger Agreement. The Company recognized $7.5 million of nonrecurring post-combination expense related to the acceleration and cash settlement of unvested historical Evergreen employee stock awards, which was recorded to operating expenses in the Company’s consolidated statements of operations in 2025.

In the event of achievement of specified milestones, the Company would be required to pay up to an additional $727.5 million in cash pursuant to the Evergreen Merger Agreement. The potential remaining milestone payments are accounted for as contingent consideration, the fair value of which is determined using a Monte Carlo simulation for sales milestones and a probability-weighted DCF approach for development and commercialization milestones. The fair value of the total contingent consideration is included in long-term contingent consideration liabilities, net of current portion in the Company’s condensed consolidated balance sheets at September 30, 2026.

The acquisition date fair value of the consideration transferred in the Evergreen Acquisition consisted of the following:

The Evergreen Acquisition was accounted for as an acquisition of a business under ASC 805,“Business Combinations(“ASC 805”),”which requires that assets acquired and liabilities assumed on the acquisition date be recognized at their fair values as of the acquisition date. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to value the assets acquired and liabilities assumed, its estimates and assumptions are subject to change during the measurement period, which is up to one year from the acquisition date. Fair value estimates are based on a complex series of judgments about future events and uncertainties and rely on estimates and assumptions. The judgments used to determine the estimated fair value assigned to each class of assets acquired and liabilities assumed, as well as asset lives, can materially impact the Company’s condensed consolidated statements of operations.

The purchase accounting for the Evergreen Acquisition has been finalized. The following table summarizes the final fair value of assets acquired and liabilities assumed as of the date of acquisition:

(1)

The value approximates the gross contractual amount of accounts receivables. The contractual amount not expected to be collected is immaterial.

(2)

Intangible assets acquired consisted of IPR&D. The fair values of the IPR&D assets were determined based on the present values of the expected cash flows to be generated by the respective underlying assets. The Company used a discount rate of 11.5%and cash flows that have been probability adjusted to reflect the risks of product commercialization, which the Company believes are appropriate and representative of market participant assumptions.

(3)

The goodwill recognized is attributable to future technologies that are not separately identifiable that could potentially add to the currently developed and pipeline products and Evergreen’s assembled workforce. Future technologies did not meet the criteria for recognition separately from goodwill because they are part of the future development and growth of the business. Goodwill of $116.2 million recognized in connection with the Evergreen Acquisition is not deductible for tax purposes.

Acquisition-related costs are not included as a component of consideration transferred but are expensed in the periods in which costs are incurred. The Company didnot incur any acquisition- and integration -related costs during the three months ended September 30, 2026. For the nine months ended September 30, 2026, the Company incurred$1.9 million of acquisition- and integration-related costs, including legal, accounting, compensation arrangements and other related fees. The Company incurred $5.8 million and $23.3 million of acquisition- and integration-related costs in the three and nine months ended September 30, 2025, respectively. These costs were recorded in operating expenses in the condensed consolidated statements of operations in the period in which they were incurred.

Lantheus Biosciences Ltd.

On July 21, 2025, Lantheus Radiopharm UK acquired the entire issued share capital of Lantheus Biosciences pursuant to the LMI Purchase Agreement with Life Medical, Life Healthcare Group Holdings Limited and Lantheus Medical as Lantheus Radiopharm UK’s guarantor (such acquisition, the “LMI Acquisition”). Lantheus Biosciences possesses an Alzheimer’s disease radiodiagnostic commercial infrastructure, R&D capabilities, and an established international footprint. The LMI Acquisition includes Neuraceq, an Alzheimer’s disease radiodiagnostic. Neuraceq is commercially approved in the United States, Canada, the European Union, the United Kingdom, Switzerland, China, Japan, South Korea, and Taiwan. As consideration for the LMI Acquisition, the Company remitted an upfront payment of $355.2 million in cash to Life Medical. In November 2025 and in accordance with the terms of the LMI Purchase Agreement, the Company finalized the net working capital accounts with Life Medical and received a $2.3 million payment from Life Medical. The Company received an additional $0.3 million working capital settlement from Life Medical in April 2026. The total $2.6 million payments were recorded as adjustments to purchase consideration since the date of acquisition. During the three months ending September 30, 2026, the Company adjusted its purchase price allocation by decreasing goodwill by $0.3 million, increasing accrued expenses and other current liabilities by $0.2 million and decreasing deferred tax liability by $0.5 million. This is the result of the Company recording a return-to-provision true-up for the period it owned Lantheus Biosciences.

In connection with the LMI Acquisition, the Company could be required to pay up to an additional $400.0 million in potential earn-out and milestone paymentsas a percentage of and upon the achievement of specified net sales thresholds, respectively, of Neuraceq and other pipeline assets. Additionally, the Company assumed a contingent consideration liability owed to Piramal (see Note 4,“Fair Value of Financial Instruments”), which is excluded from purchase consideration.

The potential remaining earn-out and milestone payments are accounted for as contingent consideration, the fair value of which is determined using a Monte Carlo simulation in a risk-neutral framework. The fair value of the total contingent consideration is included in accrued expenses and other current liabilities, long-term contingent consideration liabilities, net of current portion and other long-term liabilities in the Company’s condensed consolidated balance sheets at September 30, 2026.

The acquisition date fair value of the consideration transferred in the LMI Acquisition consisted of the following:

The LMI Acquisition was accounted for as an acquisition of a business under ASC 805, which requires that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. While the Company uses its best estimates and assumptions as part of the purchase price allocation process to value the assets acquired and liabilities assumed, its estimates and assumptions are subject to change during the measurement period, which is up to one year from the date of acquisition. Fair value estimates are based on a complex series of judgments about future events and uncertainties and rely heavily on estimates and assumptions. The judgments used to determine the estimated fair value assigned to each class of assets acquired and liabilities assumed, as well as asset lives, can materially impact the Company’s condensed consolidated statements of operations.

As of September 30, 2026, the purchase accounting for the LMI Acquisition has been finalized. The following table summarizes the final fair value of assets acquired and liabilities assumed as of the date of acquisition:

(1)

The value approximates the gross contractual amount of accounts receivables. The contractual amount not expected to be collected is immaterial.

(2)

Intangible assets acquired consisted of IPR&D and currently marketed products. The fair values of the IPR&D and currently marketed product assets were determined based on the present values of the expected cash flows to be generated by the respective underlying assets. The Company used a discount rate of 23.5% and 23.0% for IPR&D and currently marketed products, respectively. IPR&D cash flows have been probability-adjusted to reflect the risks of technical and regulatory success of the products, which the Company believes are appropriate and representative of market participant assumptions. The Company estimates that the acquired currently marketed product asset has a useful life of 10.5 years.

(3)

The goodwill recognized is attributable to future technologies that are not separately identifiable that could potentially add to the currently developed and pipeline products and Lantheus Biosciences’s assembled workforce. Future technologies did not meet the criteria for recognition separately from goodwill because they are part of the future development and growth of the business. Goodwill of $62.6 million recognized in connection with the LMI Acquisition is not deductible for tax purposes.

Acquisition-related costs are not included as a component of consideration transferred but are expensed in the periods in which costs are incurred. The Company incurred$1.9 million and$5.7 million of acquisition and integration-related costs, including legal, accounting, compensation arrangements and other related fees in the three and nine months ended September 30, 2026, respectively. The Company incurred $22.2 million and $27.6 million of acquisition- and integration-related costs in the three and nine months ended September 30, 2025, respectively. These costs were recorded in operating expenses in the condensed consolidated statements of operations in the period in which they were incurred.

Acquisition of Assets

Strategic Agreements with Perspective Therapeutics, Inc.

On January 8, 2024, the Company entered into an agreement with Perspective to participate in Perspective’s next qualified financing to purchase Perspective Shares. On January 22, 2024, the Company purchased 56,342,355 Perspective Shares, representing 11.39% of the outstanding Perspective Shares, at the fair market offering price of $0.37 pershare. Included within the agreement is a covenant which allows for the Company to designate one observer to Perspective’s board of directors, however, the Company is not currently exercising its board observer right. The Company purchased 60,431,039 Perspective Shares at a fair market purchase price of $0.95 per share as an investor in a private placement transaction on March 6, 2024, which resulted in the Company holding a cumulative 19.90% of the outstanding Perspective Shares (or 17.35% on a fully diluted basis) after giving effect to the closing of the private placement transaction. The Company’s ownership has been further diluted since the original investment was made, and Perspective effected a 1-for-10 reverse stock split. The Company does not have the ability to exercise significant influence over operating and financial policies of Perspective. See Note 4, “Fair Value of Financial Instruments,” for more information on the Company’s investment in Perspective.

Also effective January 8, 2024, the Company obtained certain options and rights from Perspective for an aggregate upfront payment of $28.0 million in cash. The options and rights received from Perspective that remain open are as follows:

•

An option from Perspective to negotiate for an exclusive license under the rights of Perspective and its affiliates to Perspective’s Pb212-VMT-α-NET, a clinical stage alpha therapy developed for the treatment of neuroendocrine tumors, to develop, manufacture, commercialize and otherwise exploit its VMT-α-NET product candidate.

•

A right to co-fund the investigational new drug application (“IND”) enabling studies for early-stage therapeutic candidates targeting prostate-specific membrane antigen and gastrin releasing peptide receptor and, prior to IND filing, a right to negotiate for an exclusive license to such candidates.

None of these options and rights have been exercised as of September 30, 2026.

During the three months ended September 30, 2026, the Company received $8.6 million in cash from the sale of 2,938,328 Perspective Shares and realized a loss of $2.3 million, which was recorded within net loss (gain) on investment in equity securities in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026.

Exclusive License for Radiopharm Theranostics Limited

On June 15, 2024, the Company entered into an agreement with Radiopharm to acquire all of Radiopharm’s rights totwo licensed then preclinical assets for an upfront payment of $2.0 million. The Company acquired global exclusive rights to both a leucine-rich repeat-containing protein 15 (“LRRC15”)-targeted monoclonal antibody and to a Trophoblast cell surface antigen-2 (“TROP2”)-targeted radiodiagnostic. LRRC15, which is also known as LNTH-2403, is a potential first-in-class, highly specific monoclonal antibody radio-conjugate with both Orphan Drug and Rare Pediatric Disease designations from the FDA for the treatment of osteosarcoma. The agent is designed to target the surrounding tumor micro-environment cells expressing the protein potentially treating a broad range of cancers. The TROP2-targeted nanobody radio-conjugate, which is also known as LNTH-2404, is designed to target TROP2, an intracellular calcium signal transducer that is overexpressed in various types of adenocarcinomas with minimal expression in normal tissues and is associated with tumor aggressiveness, poor prognosis and drug resistance.

In connection with this acquisition, the Company assumed the underlying license agreements related to the two preclinical assets, together with their respective milestone and royalty payment obligations. The Company could pay up to an additional $20.0 million in milestone payments upon achievement of specified regulatory milestones. The Company could also pay up to an additional $6.5 million in sales milestone payments upon the achievement of specified annual commercial sales thresholds in the event the Company pursues commercialization, as well as royalty payments for commercial sales. Costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use are expensed when incurred.

During the third quarter of 2024, the Company purchased 149,625,180 Radiopharm Shares, for an aggregate purchase price of approximately $5.0 million. During 2025, the Company purchased an aggregate additional 388,333,333 Radiopharm Shares for an aggregate purchase price of approximately $10.0 million. The Company does not have the ability to exercise significant influence over operating and financial policies of Radiopharm based on its ownership and because there is no participation in policy-making processes, no interchange of managerial personnel, and no sharing of technology between the Company and Radiopharm. See Note 4,“Fair Value of Financial Instruments,”for more information on the Company’s investment in Radiopharm.

Exclusive License for PNT2003/BRAVNETSA™

Under the terms of the license and collaboration agreement between Lantheus Three and POINT Biopharma Global Inc. (“POINT”), dated November 11, 2022, the Company paid POINT an upfront cash payment of $10.0 million in December 2022. Costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use are expensed when incurred, and therefore, a charge of $10.0 million was recognized in R&D expenses during the year ended December 31, 2022 for PNT2003.

On September 22, 2026, the Company announced that the FDA granted final approval for BRAVNETSA (lutetium Lu 177 dotatate), previously known as PNT2003, through the FDA’s ANDA pathway. BRAVNETSA is indicated for the treatment of adult patients with somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (“GEP-NETs”), including foregut, midgut, and hindgut neuroendocrine tumors. Upon the FDA’s final approval of BRAVNETSA, the Company was required to pay POINT a $10.0 million regulatory milestone payment, which will be paid in the fourth quarter of 2026, and which the Company has included a charge for in R&D expenses of the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026, based on the current commercialization plans for the asset.

The Company could pay up to an additional $24.5 million in milestone payments upon the achievement of specified U.S. and ex-U.S. regulatory milestones related to PNT2003. POINT is also eligible to receive up to $275.0 million in sales milestone payments upon the achievement of specified annual sales thresholds of PNT2003, as well as royalty payments of 15% of net sales of PNT2003.

MK-6240/TAUKLARIFY

On February 6, 2023, the Company acquired Cerveau. Cerveau holds the rights under a license agreement to develop and commercialize MK-6240, a radiodiagnostic agent indicated for PET imaging of the brain in adults with cognitive impairment who are being evaluated for Alzheimer’s disease to identify patients with tau neurofibrillary tangle pathology. The Company determined that its acquisition of Cerveau did not meet the definition of a business combination and accounted for the transaction as an asset acquisition.

In February 2023, the Company made an up-front payment of approximately $35.3 million to the stockholders of Cerveau (the “Cerveau Stockholders”) and paid the Cerveau Stockholders an additional $10.0 million in May 2023 upon the successful completion of a technology transfer. On August 14, 2026, the Company announced that the FDA approved MK-6240 under the brand name TAUKLARIFY (florquinitau F-18 injection). As a result of the FDA approval, the Company was required to pay the Cerveau Stockholders a $13.0 million regulatory milestone payment, which was paid in September 2026, and is included in R&D expenses in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026, based on the current commercialization plans for the asset. The Company is also required to pay Merck Sharp & Dohme Corp. a $1.3 million milestone payment upon the approval of the NDA. This amount will be paid in the fourth quarter of 2026 and was also included in R&D expenses in the Company’s condensed consolidated statements of operations for the three and nine months ended September 30, 2026.

The Company could pay up to an additional $33.0 million in milestone payments upon the achievement of specified U.S. regulatory milestones related to TAUKLARIFY. The Cerveau Stockholders are also eligible to receive up to $1.2 billion in sales milestone payments upon the achievement of specified annual commercial sales thresholds of TAUKLARIFY.

RM2 Asset Purchase

On July 3, 2024, the Company acquired from Life Molecular Imaging (now known as Lantheus Biosciences) the global rights to RM2, a gastrin-releasing peptide receptor-targeting agent, including the associated novel, clinical-stage radiotherapeutic and radiodiagnostic pair, referred to as 177Lu-DOTA-RM2 and 68Ga-DOTA-RM2 (which the Company now refers to as LNTH-2402 and LNTH-2401, respectively), for an upfront payment of $35.0 million plus a $1.0 million payment made prior to the acquisition (the “RM2 Asset Purchase”), pursuant to the Sublicense, Development and Collaboration Agreement, by and between the Company and Lantheus Biosciences, dated as of June 27, 2024 (the “RM2 Sublicense Agreement”). Pursuant to the RM2 Sublicense Agreement, the Company incurred €10.0 million in regulatory milestones in 2025, and agreed to pay up to an additional €127.5 million (reduced as discussed below) in regulatory and development milestone payments upon the achievement of clinical trial thresholds and approvals in different regions, up to €280.0 million in net sales milestone payments if products are commercialized and meet certain sales thresholds, and royalties on net sales of RM2.

Costs of IPR&D projects acquired as part of an asset acquisition that have no alternative future use are expensed when incurred, and therefore, charges of $11.2 million in 2025 and $36.0 million in 2024 were recognized in R&D expenses related to the RM2 Asset Purchase.

In connection with the LMI Acquisition, the RM2 Sublicense Agreement was amended to (i) reduce the contingent regulatory and development milestones by €45.0 million to €82.5 million;(ii) assign the right to future payments from Lantheus Biosciences to its former parent, Life Medical; and (iii) eliminate certain other non-substantive rights contained in the RM2 Sublicense Agreement (the “RM2

Amendment”). The Company determined that the RM2 Amendment did not constitute settlement of a pre-existing relationship in accordance with ASC 805, and concluded that the amendment represented a modification to the RM2 Sublicense Agreement, whereby the Company did not reacquire any incremental rights or assets. Accordingly, the Company continues to account for the RM2 Sublicense Agreement as an asset acquisition, separate from the LMI Acquisition.

19. Segment Information

The Company operates asone business segment. The results of this operating segment are regularly reviewed by the Company’s chief operating decision maker (“CODM”), the Chief Executive Officer. The CODM does not manage any part of the Company separately, and the allocation of resources and assessment of performance are based on the Company’s consolidated operating results. In order to evaluate thereportable segment’s performance, the CODM uses net income and gross margin based on the condensed consolidated statements of operations. The CODM uses net income to monitor budget and forecast versus actual results in assessing segment performance and to evaluate income generated from segment assets in deciding how to allocate resources. The measure of segment assets is reported on the condensed consolidated balance sheets as total consolidated assets.

Significant segment expenses reviewed by the CODM on a monthly basis include sales and marketing, general and administrative and R&D expenses as reported in the Company’s condensed consolidated statements of operations. However, the CODM reviews R&D expenses in more detail for certain expenses related to the Company’s development of new products and clinical programs. The approximate disaggregated amounts that comprise R&D expenses regularly reviewed by the CODM are as follows:

(1)

Other R&D expenses consist of all other R&D costs incurred for the benefit of multiple R&D programs, including legal, employee costs, depreciation, information technology, other facility-based expenses and other third-party costs.

Geographic Information

See Note 3,“Revenue from Contracts with Customers”for a disaggregation of revenue by geographic region. Long-lived assets by geographic region, which are based on asset location, are not presented because it is impracticable to do so.

20. Subsequent Events

On October 14, 2026, the Company held a special meeting of stockholders, at which the Company’s stockholders voted to adopt the Merger Agreement. On October 21, 2026, the Company received a request for additional information and documentary materials (a “Second Request”) from the Federal Trade Commission (“FTC”) in connection with the FTC’s review of the Merger. The effect of a Second Request is to extend the waiting period imposed by the HSR Act until 30 days after the Company and the Parent each have substantially complied with the Second Request issued to it, unless that period is terminated sooner by the FTC. Completion of the Merger remains subject to the expiration or termination of the waiting period under the HSR Act and the satisfaction or waiver of the other closing conditions specified in the Merger Agreement. The Company and the Parent continue to expect to consummate the Merger in the first half of 2027.