On November 25, 2024, the Company entered into an exclusive global licensing and collaboration agreement and a stock purchase agreement (collectively, the “Arrowhead Agreement”) with Arrowhead Pharmaceuticals, Inc. (“Arrowhead”), providing the Company with exclusive global rights to multiple clinical, preclinical and discovery-stage programs for rare, genetic diseases of the muscle, CNS and the lungs.

The closing of the transaction was subject to the expiration or termination of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 and other customary conditions. The agreement became effective as of February 7, 2025 (the “Effective Date”).

When the Arrowhead Agreement became effective, the Company paid Arrowhead an up-front payment of $500.0 million and invested $325.0 million in Arrowhead's common stock at a premium to the valuation on the closing date. As of the date of this report, the Company expects to record between approximately $500.0 million to $600.0 million in research and development expense for the three months ended March 31, 2025, related to those two payments to Arrowhead. Additionally, the Company will pay Arrowhead a total of $250.0 million in annual installments of $50.0 million over five years, with the first payment due on the first anniversary of the Effective Date. The Company may be obligated to make payments to Arrowhead totaling up to $10.3 billion upon the achievement of certain development, regulatory and sales milestones, inclusive of $300.0 million in near-term payments associated with the continued

enrollment of certain cohorts of a Phase 1/2 study. Furthermore, upon commercialization, the Company will be required to make tiered royalty payments based on net sales.

For the year ended December 31, 2024, there was no accounting impact as a result of the execution of the Arrowhead Agreement because the closing of the transaction did not occur until subsequent to year-end.

On December 21, 2019, the Company entered into a license, collaboration and option agreement with Roche and a stock purchase agreement (collectively, the “Roche Agreement”) with Roche, providing Roche with exclusive commercial rights to ELEVIDYS outside the U.S. The Company retains all rights to ELEVIDYS in the U.S. and will perform all development activities within the joint global development plan necessary to obtain and maintain regulatory approvals for ELEVIDYS in the U.S. and the EU, unless otherwise agreed to by the parties. Further: (i) research and development expenses incurred under the joint global development plan will be equally shared between the Company and Roche, (ii) Roche is solely responsible for all costs incurred in connection with any development activities (other than those within the joint global development plan) that are necessary to obtain or maintain regulatory approvals outside the U.S, and (iii) the Company will continue to be responsible for the manufacturing of clinical and commercial supplies of ELEVIDYS. The Company has also granted Roche options to acquire ex-U.S. rights to certain future Duchenne-specific programs (the “Options”) in exchange for separate option exercise payments, milestone and royalty considerations, and cost-sharing provisions. The agreement became effective on February 4, 2020. The Roche Agreement is governed by a joint steering committee (“JSC”) formed by representatives from Roche and the Company. The JSC, among other activities, manages the overall strategic alignment between the parties, approves any material update to the joint global development plan and budget and oversees the operations of the subcommittees.

The Company received an aggregate of approximately $1.2 billion in cash consideration from Roche, consisting of an up-front payment and an equity investment in the Company. The Company may receive up to $1.7 billion in development, regulatory and sales milestones related to ELEVIDYS. The Company receives tiered royalty payments on net sales of ELEVIDYS outside of the U.S. based on the average cost to manufacture ELEVIDYS. Of the $1.2 billion up-front cash received from Roche, (i) $312.1 million, net of issuance costs, was allocated to the approximately 2.5 million shares of the Company’s common stock issued to Roche based on the closing price when the shares were issued, (ii) $485.0 million was allocated to the Options, and (iii) $348.7 million was allocated to a single, combined performance obligation (“Combined Performance Obligation”) comprised of: (i) the license of IP relating to ELEVIDYS transferred to Roche, (ii) the related research and development services provided under the joint global development plan, (iii) the services provided to manufacture clinical supplies of ELEVIDYS, and (iv) the Company’s participation in the JSC, because the Company determined that the license of IP and related activities were not capable of being distinct from one another.

The value assigned to the Options is reflected as deferred revenue and will not be recognized until an option is either: (i) exercised by Roche, or (ii) expires. If exercised, the value will be aggregated with the option exercise price and recognized over the applicable performance period. If expired, the value will be recognized immediately. The Company recognizes revenue related to the Combined Performance Obligation on a straight-line basis over the expected performance period of the joint global development plan, which extended through the fourth quarter of 2023. Revenue relating to future development, regulatory and sales milestones will be recognized when the milestone is probable of achievement (which is typically when the milestone has occurred). Any royalties payable by Roche will be recognized in the period earned.

For the years ended December 31, 2024, 2023 and 2022, the Company recognized $114.0 million, $98.5 million and $89.2 million of collaboration and other revenues, respectively, which primarily consists of collaboration revenue, contract manufacturing revenue and royalty revenue related to the Roche Agreement.

On February 12, 2024, Roche declined to exercise a certain Option related to one external, early-stage development program, which resulted in that Option's expiry and the immediate recognition of the value assigned to that Option as collaboration revenue. As such, the Company recognized $48.0 million of collaboration revenue during the year ended December 31, 2024. As of December 31, 2024 and 2023, the Company had total deferred revenue of $455.3 million and $487.4 million, respectively, which is primarily associated with the Roche Agreement, of which $130.3 million and $50.4 million was classified as current. On February 5, 2025, an option for a certain program expired, which resulted in the immediate recognition of the value assigned to that option, $112.0 million, as collaboration revenue during the three months ended March 31, 2025. As of December 31, 2024, the amount is classified as deferred revenue, current portion, on the Company's consolidated balance sheets.

For both the years ended December 31, 2023 and 2022, the Company recognized $89.2 million of collaboration revenue, which relates to the amortization of the Combined Performance Obligation. The fair value allocated to Combined Performance Obligation was fully amortized as of December 31, 2023.

In accordance with the Roche Agreement, the parties agreed to enter into a supply agreement with Roche in order to supply them with clinical and commercial batches of ELEVIDYS (the “Supply Agreement”). Roche utilizes the supply for sales of ELEVIDYS in territories outside of the U.S where Roche has received certain approvals for ELEVIDYS. The Company is eligible to receive royalties on these sales. While the Supply Agreement is in the process of being negotiated at the issuance of this annual report, the Company delivered several batches of commercial ELEVIDYS supply to Roche that were agreed upon on a purchase order-by-purchase order basis. Contract manufacturing revenue and royalty revenue are included in collaboration and other revenues in the accompanying consolidated statements of comprehensive income (loss). The following table summarizes certain Roche activity for each of the periods indicated. There was no similar activity for the year ended 2022.


	For the Year Ended December 31,
	2024			2023
	(in thousands)
Contract manufacturing revenue	$	49,038		$	9,216
Royalty revenue		16,981			—
Cost of sales (inventory costs related to products sold to Roche)		(22,247	)		(1,818	)

The costs associated with co-development activities performed under the Roche Agreement are included in operating expenses, with any reimbursement of costs by Roche reflected as a reduction of such expenses when the related expense is incurred. For the years ended December 31, 2024, 2023 and 2022, costs reimbursable by Roche and reflected as a reduction to operating expenses were $127.1 million, $106.9 million and $117.8 million, respectively. As of December 31, 2024 and 2023, there were $34.6 million and $29.8 million of collaboration and other receivables included in other current assets on the consolidated balance sheets, respectively.

The Company entered into a sponsored research agreement in May 2017 and subsequently a license and collaboration agreement with Genethon in November 2019 (the “Genethon Collaboration Agreement”) for Genethon’s micro-dystrophin gene therapy program for the treatment of Duchenne. The Genethon Collaboration Agreement grants the Company with exclusive rights in the majority of the world (primarily excluding the EU) to Genethon’s micro-dystrophin gene therapy products (“Genethon Products”) and other micro-dystrophin gene therapy products.

Upon signing the Genethon Collaboration Agreement, the Company made an up-front payment of $28.0 million, which was recorded as research and development expense in the Company’s consolidated statements of comprehensive loss for the year ended December 31, 2019. Additionally, for the years ended December 31, 2024, 2023 and 2022, the Company recorded $6.8 million, $6.6 million and $3.5 million, respectively, of research and development expense related to reimbursable development costs incurred by Genethon for Genethon Products. For the years ended December 31, 2024, 2023 and 2022, there were no development or regulatory milestones deemed probable of being achieved and, accordingly, no additional expense has been recognized.

During May 2024, the Company and Genethon agreed to terminate the Genethon Collaboration Agreement, effective June 2024. This resulted in the elimination of all future shared development costs and future development, regulatory and sales milestone obligations.

In April 2019, the Company completed its acquisition of Myonexus Therapeutics, Inc. (“Myonexus”), a clinical-stage gene therapy biotechnology company that was developing gene therapies for LGMD for $178.3 million. The Company may also be required to make up to $200.0 million in additional payments to selling shareholders of Myonexus based on the achievement of certain sales-and regulatory- related milestones. The acquisition was accounted for as an asset acquisition as substantially all of the fair value of the gross assets acquired is concentrated in a group of similar identifiable assets (the five LGMD gene therapy programs). As part of the consideration for the transaction, the Company is required to make contingent payments to the selling shareholders of Myonexus upon the receipt and subsequent sale of a PRV with respect to a Myonexus product. As of December 31, 2024 and 2023, the contingent consideration liability was $47.1 million and $37.7 million, respectively. The changes in fair value are recorded within other income (expense), net, in the Company’s consolidated statements of comprehensive income (loss). Please read Note 5, Fair Value Measurements for further information on the change in fair value of the contingent consideration liability.

In December 2016, the Company entered into an exclusive option agreement with Nationwide from which the Company obtained an exclusive right to acquire a worldwide license of the micro-dystrophin gene therapy technology for Duchenne and Becker

muscular dystrophy. In October 2018, the Company exercised the option and entered into a license agreement with Nationwide, which granted the Company exclusive worldwide rights to develop, manufacture and commercialize a micro-dystrophin gene therapy product candidate. Under this agreement, the Company is liable for future regulatory milestone, sales milestone and sublicense payments as well as lower single-digit royalties upon commercialization.

During the year ended December 31, 2023, the Company recorded $23.0 million as an in-licensed right intangible asset in its consolidated balance sheets, $10.0 million of which related to the regulatory approval of ELEVIDYS, and the remaining related to sales-based milestones as the Company determined that all sales-based milestones were achieved or were probable of being achieved. As of December 31, 2024, the in-licensed right asset with a net carrying value of $20.6 million is being amortized on a straight-line basis over the remaining life of the relevant patent. Royalty payments due to Nationwide associated with commercial sales of ELEVIDYS totaled $30.6 million and $6.0 million for the years ended December 31, 2024 and 2023, respectively, and were recorded as cost of sales in the accompanying consolidated statements of comprehensive income (loss).

In July 2017, the Company and UWA entered into a settlement agreement with BioMarin, and simultaneously entered into a license agreement, which was subsequently amended in April 2019 (the “BioMarin Agreement”), with BioMarin and Academisch Ziekenhuis Leiden (collectively with the Company, UWA and BioMarin, the “Settlement Parties”). The BioMarin Agreement provides the Company with an exclusive license to certain intellectual property with an option to convert the exclusive license into a co-exclusive license and the Settlement Parties agreed to stop most existing efforts to continue with ongoing litigation and opposition and other administrative proceedings concerning BioMarin’s intellectual property. BioMarin is also eligible to receive tiered royalty payments, ranging from 4% to 8%, based on the net sales for the three products and product candidates.

In November 2021, the Company entered into a second settlement agreement and second amendment to the license agreement (the “Second Amendment”), which waived certain future milestone payments and altered royalty payment terms of the agreement. Under the Second Amendment, the Company may be liable for up to approximately $50.0 million in regulatory milestones for eteplirsen, casimersen and golodirsen. In addition, on and after July 1, 2022, the tiered royalty payments ranged from 4% to 5%. The royalty terms under the license agreement expired in March 2024 in the U.S. and expired as of December 31, 2024 in the EU and other countries.

As a result of the execution of the license agreement with BioMarin, the Company recorded an in-licensed right intangible asset of $6.6 million in its consolidated balance sheets as of December 31, 2017, representing the fair value of the U.S. license to BioMarin’s intellectual property. The intangible asset is being amortized on a straight-line basis over the remaining life of the patent and has a carrying value of $1.8 million as of December 31, 2024.

For the years ended December 31, 2024, 2023 and 2022, the Company recognized royalty expense of $4.4 million, $17.6 million and $30.4 million, respectively, which is included in cost of sales in the accompanying consolidated statements of comprehensive income (loss). For the years ended December 31, 2024, 2023 and 2022, no regulatory milestones were deemed probable of being achieved and, accordingly, no additional in-licensed rights or expenses have been recognized.

In April 2013, the Company and UWA entered into an amendment to an existing exclusive license agreement relating to the treatment of Duchenne by inducing the skipping of certain exons. The agreement was further amended in June 2016. Under the amended agreement, the Company may be obligated to make payments to UWA totaling up to $26.0 million upon the achievement of certain development, regulatory and sales milestones. Additionally, the Company is required to pay a low-single-digit percentage royalty on net sales of products covered by issued patents licensed under the agreements with UWA. Corresponding to the FDA approval of EXONDYS 51 in 2016, VYONDYS 53 in 2019, and AMONDYS 45 in 2021, the Company recorded milestone payments of $1.0 million, $0.5 million and $0.5 million as in-licensed right intangible assets in its consolidated balance sheets, respectively. Each in-licensed right is being amortized on a straight-line basis over the remaining life of the relevant patents and have a combined carrying value of $0.5 million as of December 31, 2024. For the years ended December 31, 2024, 2023 and 2022, the Company recorded $12.1 million, $11.8 million and $10.5 million in royalty expense, respectively, which is included in cost of sales, related to agreements with UWA. For the years ended December 31, 2024, 2023 and 2022, no development, regulatory or sales milestones were deemed probable of being achieved and, accordingly, no additional in-licensed rights or expenses have been recognized.

The Company has research and option agreements with third parties in order to develop various technologies and biologics that may be used in the administration of the Company’s genetic therapeutics. The agreements generally provide for research services related to pre-clinical development programs and options to license the technology for clinical development. Prior to the options under these agreements being executed, the Company may be required to make up to $34.8 million in research milestone payments. Under these agreements, there are $116.8 million in potential option payments to be made by the Company upon the determination to exercise the options. Additionally, if the options for each agreement are executed, the Company would incur additional contingent obligations and may be required to make development, regulatory, and sales milestone payments and royalty payments based on the sales of the developed products upon commercialization.

For the years ended December 31, 2023 and 2022, the Company recognized $5.1 million, and $6.0 million in research, option and milestone expense as research and development expense in the accompanying consolidated statements of comprehensive income (loss), respectively, with no similar activity during the year ended December 31, 2024. For the years ended December 31, 2023 and 2022, the Company exercised options in a research and option agreement and recognized $7.5 million and $8.5 million, respectively, of up-front expense as research and development expense in the accompanying consolidated statements of comprehensive income (loss), separately from the research, option and milestone expense listed above, with no similar activity for the year ended December 31, 2024.

Including the agreements discussed above, the Company has license and collaboration agreements in place for which it could be obligated to pay, in addition to the payment of up-front fees upon execution of the agreements, certain milestone payments as a product candidate proceeds from the submission of an investigational new drug application through approval for commercial sale and beyond. As of December 31, 2024, the Company may be obligated to make up to $2.3 billion of future development, regulatory, commercial, and up-front royalty payments associated with its collaboration and license agreements. These obligations exclude potential future option and milestone payments for options that have yet to be exercised within agreements entered into by the Company as of December 31, 2024, as well as the Arrowhead Agreement that had not yet closed as of December 31, 2024, which are discussed above. For the years ended December 31, 2023 and 2022, the Company recognized approximately $13.2 million and $32.6 million relating to certain up-front, milestone, settlement and other payments as research and development expense, respectively, under these agreements, with no similar activity for the year ended December 31, 2024.