Collaboration and License Agreements

9 Months Ended

Sep. 30, 2025

License Agreement with Sanofi

On September 9, 2024 (Acquisition Date), the Company closed the license agreement with Amunix Pharmaceuticals, Inc., a Sanofi company, previously announced on August 1, 2024 (Sanofi Agreement). The Sanofi Agreement provides the Company with an exclusive worldwide license to use of the proprietary PRO-XTEN® universal masking technology for oncology and infectious disease, excluding the ophthalmological field, and to three early-stage clinical dual-masked TCEs that all leverage the PRO-XTEN® universal masking platform within a range of oncology indications.

Under the Sanofi Agreement the Company made an upfront payment to Sanofi in the amount of $100.0 million and placed into escrow a $75.0 million milestone payment due to former shareholders of Amunix Pharmaceuticals, Inc., which is subject to VIR-5525 achieving “first in human dosing” by 2026. In July 2025, the first patient was dosed in phase 1 study evaluating VIR-5525. During the three months ended September 30, 2025, the Company paid the $75.0 million milestone, which was recorded as part of research and development expenses in the Company’s unaudited condensed statement of operations for the three and nine months ended September 30, 2025.

Sanofi will also be eligible to receive up to an additional $323.0 million in future development and regulatory milestone payments, up to an additional $1.49 billion in commercial net sales-based milestone payments, and low single-digit to low double-digit tiered royalties on worldwide net sales. In addition, if, within a two-year period from the execution of the Sanofi Agreement, the Company executes a transaction that gives rise to Vir Bio receiving certain sublicense income related to the licenses obtained from the Sanofi Agreement, Sanofi may be eligible to receive a portion of such income.

Additionally, as part of the Sanofi Agreement, the Company paid $3.7 million to acquire certain lab equipment and cash deposits primarily related to contract manufacturing agreements. Shortly after the closing of the Sanofi Agreement, the Company hired certain former Sanofi personnel. The Company incurred approximately $4.6 million of transaction costs associated with the closing of the Sanofi Agreement. The following table summarizes the aggregate amount paid for the assets acquired by the Company in connection with the Sanofi Agreement as of the Acquisition Date (in thousands):


Upfront	$	100,000
Equipment	1,150
Deposits	2,580
Transaction costs	4,612
Total purchase consideration	$	108,342

The Company accounted for the Sanofi Agreement as an asset acquisition in accordance ASC 805-50 as substantially all of the fair value of the assets acquired is concentrated in a group of similar identifiable assets. The three early-stage clinical oncology TCEs use the same universal PRO-XTEN® masking technology and have similar development timelines, probabilities of risk, and loss of patent exclusivity among other characteristics. ASC 805-50 requires the acquiring entity in an asset acquisition to recognize assets acquired and liabilities assumed based on the cost to the acquiring entity on a relative fair value basis, which includes consideration given. The total purchase price was allocated to the acquired assets based on their relative fair values, as of the Acquisition Date as follows (in thousands):


In-process research and development (IPR&D)	$	102,836
Property and equipment	1,119
Prepaid expenses and other current assets (1)	3,975
Assembled workforce	412
Total purchase consideration	$	108,342

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(1) Includes acquired cash deposits primarily related to contract manufacturing agreements.

The fair value of the IPR&D was estimated using a multi-period excess earnings income approach that discounts expected cash flows to present value by applying a discount rate that represents the estimated rate that market participants would require for the intangible asset. The expected cash flows and related discount rate are significant unobservable inputs categorized within Level 3 of the fair value hierarchy. In accordance with ASC 730, as the three early-stage clinical oncology TCEs have not achieved regulatory approval when acquired, the portion of the purchase price allocated to the IPR&D was immediately expensed to research and development expenses as they had no alternative future use. Contingent milestone payments were determined to be within the scope of ASC 450 and will be recognized when the contingency is resolved and the consideration is paid or becomes payable. Any milestone payments made in the future will either be expensed as research and development or capitalized as a developed asset based on when regulatory approval is obtained. The Company will recognize sales-based milestone and royalty payments in cost of sales as revenue from product sales is recognized. The fair value of the assembled workforce was estimated using a replacement cost method. The assembled workforce is classified as intangible assets, net and is amortized over an expected useful life of five years.

Alnylam Pharmaceuticals, Inc.

In October 2017, the Company and Alnylam Pharmaceuticals, Inc. (Alnylam) entered into a collaboration and license agreement (the Alnylam Agreement). Under the Alnylam Agreement, the Company obtained a worldwide, exclusive license to develop, manufacture and commercialize siRNA product candidates, including elebsiran, for all uses and purposes including the treatment of hepatitis B virus (HBV) and hepatitis delta virus (HDV). Under the Alnylam Agreement, the Company also held options to obtain similar licenses to siRNA product candidates for up to four other infectious disease targets selected by Vir Bio, but following an amendment and restatement of the Alnylam Agreement in March 2025 (the Restated Alnylam Agreement), those options (and all rights and obligations related to those infectious disease targets) were terminated. At the same time Alnylam elected to not opt-in to the profit-sharing arrangement with respect to any approved siRNA product candidates, including elebsiran, directed to HBV or HDV. The Company remains solely responsible, at its expense, for conducting all development, manufacture and commercialization activities for elebsiran in HBV and HDV indications, and the Company is required to use commercially reasonable efforts to develop and commercialize elebsiran for the treatment of HBV or HDV in the United States and specified major markets.

In connection with the Restated Alnylam Agreement and Alnylam’s election to not opt-in to the profit-sharing arrangement, the Company paid Alnylam $30.0 million, which was recorded as part of research and development expenses in the Company’s unaudited condensed statement of operations for the nine months ended September 30, 2025. After this payment, the remaining amount of the development and regulatory milestones is up to $145.0 million, down from the $175.0 million as previously disclosed in the audited consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2024. Any development and regulatory milestones for an elebsiran product will be payable to Alnylam only once, irrespective of dosage, formulation forms, route of administration or indication. Following commercialization, the Company will be required to pay to Alnylam up to $250.0 million in the aggregate for the first achievement of specified levels of net sales by elebsiran products directed to HBV, whether for the treatment of HBV or HDV. The Company will also be required to pay Alnylam tiered royalties at percentages ranging from the low double-digits to mid-teens on annual net sales of siRNA products directed to HBV, such as elebsiran, whether for the treatment of HBV or HDV, subject to specified reductions and offsets. The royalties are payable on a product-by-product and country-by-country basis until the later of the expiration of all valid claims of specified patents covering such product in such country and 10 years after the first commercial sale of such product in such country. Alnylam may also be entitled to receive a portion of any consideration the Company receives as a result of granting a sublicense under the licenses granted to Vir Bio by Alnylam under the Alnylam Agreement.

The term of the Restated Alnylam Agreement will continue, on a product-by-product and country-by-country basis, until expiration of all royalty payment obligations under the Restated Alnylam Agreement. The Company may terminate the Alnylam Agreement on a program-by-program basis or in its entirety for any reason on 90 days’ written notice. Either party may terminate the agreement for cause for the other party’s uncured material breach on 60 days’ written notice (or 30 days’ notice for payment breach), or if the other party challenges the validity or enforceability of any patent licensed to it under the Restated Alnylam Agreement on 30 days’ notice.