There have been no material changes to the risk factors set forth in our Annual Report on Form 10-K for the year ended December 31, 2025 (our “Form 10-K”), except as set forth below: Risks Related to Our Pending Merger with Curium US Holdings LLC We may not complete the pending transaction with Curium US Holdings LLC (the “Parent”) within the time frame we anticipate or at all, which could have an adverse effect on our business, financial results, operations and/or the market price of our common stock. On August 3, 2026, we entered into an Agreement and Plan of Merger (the “Merger Agreement”) with the Parent and Coco Merger Sub Inc. (the “Merger Sub”), pursuant to which, on the terms and subject to the conditions set forth in the Merger Agreement, the Merger Sub will merge with and into us and we will continue as the surviving corporation in such merger as a wholly-owned subsidiary of the Parent (the “Merger”). The completion of the Merger is subject to the fulfillment or waiver of certain customary mutual closing conditions, including, among other things, (i) the adoption of the Merger Agreement by the affirmative vote of the holders of a majority of the outstanding shares of our common stock entitled to vote at our shareholders meeting, (ii) the absence of any law or order by a governmental authority of competent jurisdiction prohibiting or otherwise making illegal the consummation of the Merger, (iii) the expiration or termination of the applicable waiting period (or any extensions thereof) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, (iv) that no voluntary agreement between the parties and a governmental entity not to consummate the Merger shall be in effect and (v) that certain other specified approvals, filings, notifications, clearances or expirations or terminations of waiting periods shall have occurred or been obtained, made or waived, as applicable. The obligation of each party to consummate the Merger is also conditioned upon (i) the accuracy of the other party’s representations and warranties, (subject, in certain cases, to certain customary materiality qualifications) and (ii) the other party’s performance or compliance in all material respects with its obligations under the Merger Agreement. In addition, the obligation of Parent and Merger Sub to consummate the Merger is also conditioned up on there being no continuing Material Adverse Effect (as defined in the Merger Agreement) having occurred that is continuing at the Effective Time. In addition, we have certain customary termination rights pursuant to the Merger Agreement, including our right to terminate the Merger Agreement to accept a “Superior Proposal” (as defined in the Merger Agreement) subject to compliance with certain procedures specified in the Merger Agreement. As a result, we cannot assure you that all of the various closing conditions will be satisfied and that the Merger with the Parent will be completed, or that, if completed, it will be exactly on the terms set forth in the Merger Agreement or within the expected time frame. If the Merger is not completed within the expected time frame or at all, we may be subject to a number of material risks. The price of our common stock may decline to the extent that the current market price of our common stock reflects a market assumption that the Merger will be completed. We could also be required to pay the Parent a termination fee if the Merger Agreement is terminated under specific circumstances set forth in the Merger Agreement. The failure to complete the Merger also may result in negative publicity, a decline in investor confidence, stockholder litigation being brought against us, adverse impacts to our relationships with our existing and prospective employees, collaborators, customers, regulators, suppliers and other business partners, us being unable to recruit prospective employees or to retain and motivate existing employees, and adverse financial impacts due to costs incurred in connection with the Merger. We may also be required to devote significant time and resources to litigation related to any failure to complete the Merger or related to any enforcement proceeding commenced against us to perform our obligations under the Merger Agreement. The pendency of the Merger with the Parent could adversely affect our business, financial results, operations and/or the market price of our common stock. Our efforts to complete the Merger could cause substantial disruptions in, and create uncertainty surrounding, our business, which may materially adversely affect our results of operation and our business. Uncertainty as to whether the Merger will be completed may affect our ability to recruit prospective employees or to retain and motivate existing employees. Employee retention may be particularly challenging while the Merger is pending because employees may experience uncertainty about their roles following consummation of the Merger. Our 52 Table of Contents management’s and certain of our employees’ attention is being directed toward the completion of the Merger and thus is being diverted to some extent from our day-to-day operations. Uncertainty as to our future could adversely affect our business and our relationship with collaborators, customers, regulators, suppliers and other business partners. For example, collaborators, suppliers, and other counterparties may defer decisions concerning working with us, or seek to change existing business relationships with us. Changes to or termination of existing business relationships could adversely affect our results of operations and financial condition, as well as the market price of our common stock. The adverse effects of the pendency of the Merger could be exacerbated by any delays in completion of the Merger or termination of the Merger Agreement. We are subject to certain restrictions on the conduct of our business under the terms of the Merger Agreement. Under the terms of the Merger Agreement, we have agreed to certain restrictions (unless approved by the Parent) on the operations of our business that could harm our business relationships, financial condition, operating results, cash flows and business, including restrictions with respect to our ability to, among other things, subject to certain specified exceptions: incur capital expenditures in excess of a specified aggregate amount for an applicable calendar year, incur or assume any long-term or short-term indebtedness for borrowed money or materially modify the terms of any indebtedness for borrowed money other than revolver borrowings or letters of credit in the ordinary course of business, commence any clinical study except for select studies or discontinue, terminate or suspend any ongoing clinical study other than (i) for efficacy or safety reasons, (ii) as mandated by any health regulatory authority or (iii) pursuant to any discontinuation, termination or suspension, for bona fide business reasons. Because of these restrictions, we may be prevented from undertaking certain actions with respect to the conduct of our business that we might otherwise have taken if not for the Merger Agreement. Such restrictions could prevent us from pursuing certain business opportunities that arise prior to the effective time of the Merger and are outside the ordinary course of business and could otherwise adversely affect our business and operations prior to completion of the Merger. In certain instances, the Merger Agreement requires us to pay a termination fee to the Parent, which could require us to use available cash that would have otherwise been available for general corporate purposes. Under the terms of the Merger Agreement, we may be required to pay the Parent a termination fee of $228.0 million if the Merger Agreement is terminated under specific circumstances therein, including, but not limited to, in the event we accept and enter into an agreement for the consummation of a transaction which our Board of Directors (“Board”) determines is a Superior Proposal. If the Merger Agreement is terminated under such circumstances, the termination fee we would be required to pay under the Merger Agreement may require us to use available cash that would have otherwise been available for general corporate purposes and other uses. For these and other reasons, termination of the Merger Agreement could materially and adversely affect our business operations and financial condition, which in turn would materially and adversely affect the price of our common stock. We have incurred, and will continue to incur, direct and indirect costs as a result of the Merger. We have incurred, and will continue to incur, significant costs and expenses, including regulatory costs, fees for professional services and other transaction costs in connection with the Merger, for which we will have received little or no benefit if the Merger is not completed. There are a number of factors beyond our control that could affect the total amount or the timing of these costs and expenses. Many of these fees and costs will be payable by us even if the Merger is not completed and may relate to activities that we would not have undertaken other than to complete the Merger. Lawsuits relating to the Merger could be filed against us, including by our stockholders. Although litigation is common in connection with acquisitions of public companies in the United States, regardless of any merits related to the underlying acquisition, the outcome of any lawsuits filed against us is uncertain and could delay or prevent completion of the Merger. We may not be successful in defending against any such claims. Additionally, the costs of defense of such litigation, including costs associated with the indemnification of directors and officers, and other effects, such as negative publicity or damage to our relationships with business partners, suppliers and customers, could have an adverse effect on our business, financial condition and operating results. The Merger Agreement contains provisions that could discourage a potential competing acquirer of our company or could result in any competing proposal being at a lower price than it might otherwise be. We are subject to certain restrictions on our ability to solicit alternative acquisition proposals from third parties, to provide information to third parties and to enter into or continue discussions or negotiations with third parties regarding alternative acquisition proposals, subject to customary exceptions. In addition, we may be required to pay the Parent a termination fee of $228.0 million under specific circumstances described in the Merger Agreement, including, but not limited to, in the event we accept and enter into an agreement for the consummation of a transaction which our Board determines is a Superior Proposal. These provisions could discourage a potential competing acquirer that might 53 Table of Contents have an interest in acquiring all or a significant part of our company from considering or proposing such an acquisition, including, if the Merger Agreement is terminated prior to the consummation of the Merger, after such termination of the Merger Agreement, even if it were prepared to pay a purchase price per share higher than the purchase price per share proposed to be paid in the Merger, or might result in a potential competing acquirer proposing to pay a lower price than it might otherwise have proposed to pay because of the added expense of the termination fee that may become payable in specified circumstances under the Merger Agreement, including, in certain circumstances, after a valid termination of the Merger Agreement in accordance with the terms thereof. Because the value of the contingent value rights (“CVRs”) is uncertain, our stockholders cannot be certain of the precise value of the consideration they may receive in the Merger. At the time the Merger is completed, each issued and outstanding share of our common stock will be automatically cancelled and converted into the right to receive $102.50 per share in cash, without interest, plus a non-transferable CVR to receive up to $12.00 in cash, for total potential consideration of $114.50 per share in cash. The non-transferable CVR will be issued to our stockholders at closing and paid, in whole or in part, following achievement of certain specified milestones. There can be no assurance that any payment will be made under the CVR, or regarding the amount or timing of any such payment. As mentioned above, any amounts to be received in connection with the CVR are contingent upon achievement of certain specified milestones, which may or may not occur. Risks Related to Our and Our Strategic Partners’ Portfolios of Clinical Development Candidates We may not, or may take longer to, realize the expected benefits and opportunities related to PYLARIFY TruVu, our recently-approved new formulation of our prostate-specific membrane antigen (“PSMA”) positron emission tomography (“PET”) Imaging Agent. On March 6, 2026, the U.S. Food and Drug Administration (the “FDA”) approved PYLARIFY TruVu (piflufolastat F18), a new formulation of our F-18 PSMA PET imaging agent. PYLARIFY TruVu is designed to enhance product stability at higher radioactive concentrations, supporting more efficient manufacturing and distribution, including the potential to increase batch sizes and serve broader geographic markets. PYLARIFY TruVu is expected to become commercially available beginning in the fourth quarter of 2026 and will be introduced on a rolling geographic basis, with the intent to transition customers from PYLARIFY to PYLARIFY TruVu. It is anticipated that once a PMF site receives FDA approval to manufacture PYLARIFY TruVu and begins to supply PYLARIFY TruVu commercially, it will no longer supply PYLARIFY. We plan to work closely with clinicians and PET manufacturing facility (“PMF”) sites to support a smooth transition, including providing guidance on ordering, handling, and clinical use to support continuity of care. We are also pursuing reimbursement for PYLARIFY TruVu from the Centers for Medicare and Medicaid Services (“CMS”), including seeking three years of transitional pass-through payment status (“TPT Status”). In the second quarter of 2026, we submitted applications for both Healthcare Common Procedure Coding System (“HCPCS”) coding and TPT Status, with a targeted October 1, 2026 effective date for both. On July 24, 2026, CMS granted a HCPCS code for PYLARIFY TruVu, with an effective date of October 1, 2026. However, we can provide no assurance that we will be able to complete the technology transfer across our PMF network for PYLARIFY TruVu or obtain FDA approval for each PMF site to manufacture PYLARIFY TruVu on our expected timeline or at all. Additionally, we may be unable to obtain adequate coverage and payment, including TPT Status, for PYLARIFY TruVu on our expected timeline or at all, and payers may not add the HCPCS code to their systems on our expected timeline. Furthermore, there is no assurance that any customer transition will occur on our expected timeline or that our customers will adopt PYLARIFY TruVu at all. If customers do not adopt PYLARIFY TruVu we may not be able to reintroduce PYLARIFY and we would then lose customers to competitors which would have an adverse effect on our business, results of operations, financial condition and cash flows. All of the risks as described in Part I, Item 1A, “Risk Factors” in our Form 10-K with respect to our ability to continue to generate substantial revenue from PYLARIFY, as well as the risks associated with launching a product, also apply to PYLARIFY TruVu, and we can provide no assurances that the anticipated increase in batch size or other expected improvements associated with the design of the new formulation will be realized or be viewed in the market as differentiating factors. We may not, or may take longer to, realize the expected benefits and opportunities related to our acquisition of the rights to LNTH-2501. In April 2025, we acquired Evergreen, including the rights to LNTH-2501. On October 30, 2025, we announced that the FDA had accepted our New Drug Application (“NDA”) for LNTH-2501 and set a PDUFA target action date of March 29, 2026. On March 17, 2026, the FDA extended its review of the NDA, moving the PDUFA target action date to June 29, 2026, which would allow the FDA additional time to review and consider further manufacturing-related information. On June 26, 2026, we announced that the FDA issued a Complete Response Letter (“CRL”) regarding the NDA, stating that the agency could not approve the NDA by the June 29, 2026 extended PDUFA target action date due to unresolved third-party facility manufacturing-related conditions. The third-party facility is responsible for drug product manufacturing. Satisfactory resolution of the unresolved facility inspection-related conditions is required before the LNTH-2501 NDA may be approved. The CRL did not identify any concerns regarding the data we submitted in support of the application, nor did it identify any issues 54 Table of Contents related to the safety or efficacy of LNTH-2501. We can provide no assurance that the third-party facility manufacturing-related conditions identified in the CRL will be resolved in a manner satisfactory to the FDA, that LNTH-2501 will be approved by the FDA in a timely manner or at all. If LNTH-2501 is approved, there is no guarantee that we will be successful in gaining post-approval market acceptance and adequate coding, coverage, and payment for LNTH-2501 or that our manufacturer will be able to successfully develop and scale the manufacturing capabilities to support the launch of LNTH-2501. Even if we do receive NDA approval, all of the risks as described in Part I, Item 1A, “Risk Factors” in our Form 10-K with respect to launching a product would apply to LNTH-2501. Additionally, LNTH-2501 is a kit product with a supply chain that differs from that of our other commercial products, which may introduce additional operational complexity, coordination requirements, and sourcing and supply risks, and we can provide no assurance that we will be able to successfully or timely launch LNTH-2501, achieve anticipated adoption, or realize expected commercial results. We may not, or may take longer to, realize the expected benefits and opportunities related to, the POINT Biopharma Global Inc. (“POINT”) License Agreements, including PNT2003. On December 20, 2022, we announced the closing of a set of strategic collaborations with an affiliate of POINT, in which we were granted a license to exclusive worldwide rights (excluding Japan, South Korea, China (including Hong Kong, Macau and Taiwan), Singapore and Indonesia) to co-develop and commercialize POINT’s PNT2003 and PNT2002 product candidates (the “POINT License Agreements”). The expected benefits and opportunities related to the POINT License Agreements and related agreements for the supply of PNT2003 by POINT may not be realized or may take longer to realize than expected due to, for example, challenges and uncertainties inherent in product research, development, manufacturing, regulatory approval, marketing and competition. In particular, activities under the POINT License Agreements may not result in viable products suitable for commercialization in a timely manner or at all, due to a variety of reasons, including any inability of the relevant parties to perform their commitments and obligations under the POINT License Agreements, our ability to obtain final FDA approval for PNT2003, to successfully defend the favorable U.S. District Court ruling invalidating all patents asserted by Advanced Accelerator Applications USA, Inc. and Advanced Accelerator Applications SA as part of the PNT2003 Hatch-Waxman litigation through any appeals, and, if approved by the FDA, the timing, execution and success of launching and commercializing PNT2003. The POINT License Agreements impose various development, regulatory filing, commercialization and other obligations on us, and require us to meet development timelines or to exercise commercially reasonable efforts to develop and commercialize licensed products. With respect to PNT2003, in March 2026, we announced tentative approval of our Abbreviated New Drug Application (“ANDA”) for PNT2003, which indicates that the FDA has completed its review of the ANDA and determined that it meets the requirements for approval. The timing of our launch will consider the following factors: the timing of final FDA approval and disposition of legal proceedings related to the Hatch-Waxman process, as well as manufacturing and commercial readiness to ensure launch success. Even if we do receive ANDA approval, all of the risks as described in Part I, Item 1A, “Risk Factors” in our Form 10-K with respect to launching and successfully commercializing a radiopharmaceutical product as well as those related to our dependence on third parties for the manufacturing of products would apply to PNT2003. In addition, we are also currently dependent on POINT to develop commercial product capacity and manufacture for both PNT2003 and PNT2002. Disagreements with POINT in the POINT License Agreements over proprietary rights, contract interpretation or the preferred course of product research, development, regulatory strategy or marketing, might cause delays in performance of the POINT License Agreements or termination of the POINT License Agreements, or might result in litigation or arbitration, which could be time-consuming and expensive. Additionally, if we fail to comply with our obligations under the POINT License Agreements, then POINT may conclude that we have materially breached and may terminate one or both of the POINT License Agreements, in which event we may lose our rights to develop and market PNT2003 and PNT2002 or incur liability for damages. The Phase 3 registrational clinical trial for PNT2002, known as the “SPLASH” study, reached 100% of prespecified overall survival events. The results of the readout were comparable to the previously reported 46% and 75% readouts and remain confounded by the overwhelming number of patients who crossed over within the study to receive PNT2002. As a result, we may never realize any future benefits from the related POINT License Agreement. Any of the foregoing risks could have a material adverse effect on our business, results of operations, financial condition and cash flows. Risks Related to Our Business Operations and Financial Results We may not receive the expected financial benefits from our sale of our single-photon emission computerized tomography (“SPECT”) business, and a failure to receive future and contingent payments could adversely affect our liquidity and financial condition. 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 Holdings, Inc. (“Illuminated”), SHINE 55 Table of Contents 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”), we are entitled to receive future and contingent consideration, including (i) a seller note with a principal amount of $20.0 million (the “Seller Note”), which bears interest at 8.0% per year payable semi-annually (with up to half payable in-kind) and matures on the earlier of January 1, 2029 or completion of an initial public offering by Illuminated (a “SHINE IPO”), and which may be repaid earlier in certain circumstances, including in connection with a change in control or a material financing, as defined in the governing note agreement, and (ii) $20.0 million in cash on the earlier of January 1, 2029 or a SHINE IPO (the “Deferred Cash Purchase Price”), with an additional $5.0 million payable if the Deferred Cash Purchase Price is not paid by January 1, 2029, for a total of $25.0 million in cash to be paid no later than January 1, 2030. In addition, we 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. There can be no assurance that SHINE SPECT will have sufficient financial resources to make payments on the Seller Note or the Deferred Cash Purchase Price as they come due, or at all. The Seller Note is an unsecured obligation, and we do not have collateral protection in the event of non-payment, insolvency or other financial distress of SHINE SPECT. Further, the contingent consideration depends on the achievement of specified revenue milestones that may not be achieved in whole or in part, may take longer than we expect to be achieved, or may never be achieved, and the form of any contingent consideration may include equity rather than cash. If we do not receive some or all of these future and contingent payments, or if receipt of these amounts is delayed, disputed or otherwise not realized on the expected terms or timing, our liquidity, financial condition and results of operations could be materially adversely affected. In addition, we received a 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”). Illuminated completed a qualified financing in February 2026, resulting in the conversion of the Installment Note into Series E-1 convertible preferred stock of Illuminated (the “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 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. There can be no assurance that the Series E-1 Preferred will maintain their current value, that the common stock into which they are convertible will have value or be freely tradeable, or that we will otherwise receive any financial benefits from holding the Series E-1 Preferred. Further, because the shares do not have a readily determinable fair value, the fair value that Illuminated or another third party may attribute to them could be different than the fair value that we have determined. If the value of the Series E-1 Preferred declines, or if we are unable to realize the value from the Series E-1 Preferred on a timely basis or at all, our liquidity, financial condition and results of operations could be materially adversely affected. We may not be successful in identifying a transaction partner or buyer for our radiotherapeutic assets, and the pursuit of strategic alternatives could adversely affect our business. As previously announced, we are pursuing value-maximizing alternatives for our radiotherapeutic assets. We are evaluating potential transactions, however, there can be no assurance that this process will result in the identification of a suitable buyer, partner or transaction structure, or that any transaction will be completed on acceptable terms, within this anticipated timeframe, or at all. Market conditions, financing availability, regulatory considerations, due diligence findings, valuation expectations and other factors could adversely affect our ability to consummate such a transaction. The pursuit of strategic alternatives is complex and time-consuming and may divert the attention of management and other personnel from the operation of our business, execution of our strategic priorities, commercialization activities and advancement of our development programs. In addition, uncertainty regarding the outcome of the process may adversely affect our relationships with employees, customers, suppliers, strategic partners and investors, result in the loss of key personnel, or otherwise disrupt our operations. If we are unable to complete a transaction, or if a transaction is delayed or completed on terms that are less favorable than anticipated, we may incur significant costs without realizing the anticipated strategic, operational or financial benefits. Any of these factors could have a material adverse effect on our business, results of operations, financial condition and cash flows. Risks Related to Our Capital Structure Our business and operations could be negatively affected by any pending or future securities litigation or claims that we have otherwise engaged in wrongdoing. 56 Table of Contents We are, and may become in the future, subject to securities class actions, derivative suits or other securities-related legal actions. For example, on September 9, 2025, an alleged stockholder initiated a putative securities class action against us 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 our 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, we filed a motion to dismiss the amended complaint on May 11, 2026, and under the operative scheduling order that motion will be fully briefed by August 10, 2026. Additionally, on December 17, 2025, another alleged stockholder 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 our 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, we cannot predict how or when these matters will ultimately be resolved. These actions, or any other stockholder litigation against us, could cause us to incur substantial costs defending the lawsuit. Such a lawsuit could also divert the time and attention of our management from our business, which could significantly harm our profitability and reputation. If any of these actions are resolved adversely to us, the amount of any potential loss is difficult to predict, and an adverse resolution could materially and adversely affect our business and financial condition. 57 Table of Contents