6. Acquisitions

Generation Bio Acquisition

On December 15, 2025, the Company entered into the Generation Bio Merger Agreement, pursuant to which the Company acquired Generation Bio through a tender offer for (i) $4.2913 in cash per share of Generation Bio common stock and (ii) one non-transferable CVR per share of Generation Bio common stock. In-the-money Generation Bio options were vested immediately upon closing of the tender offer and were entitled to $4.2913 less the exercise price per Generation Bio option in cash. The merger closed on February 9, 2026, and XRA 7 merged with and into Generation Bio. Following the merger, Generation Bio continued as the surviving entity and became a wholly-owned subsidiary of the Company.

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Under the Generation Bio CVR Agreement, CVR holders are entitled to a portion of the net proceeds from the sale, transfer, license or other disposition or monetization of any or all of Generation Bio’s legacy IP rights and patents for ten years following the Generation Bio Merger Closing Date, if such transactions occur within five years following such date. CVR holders are entitled to receive 70% of these net proceeds during years one through two, 60% during years three through four, 50% during years five through six, and 30% during years seven through ten following the Generation Bio Merger Closing Date.

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CVR holders are also entitled to receive a portion of the net proceeds related to the Moderna Collaboration and License Agreement (as discussed below), including 90% of the net proceeds during years one through three, 80% during

years four through five, 70% during years six through seven, and 50% during years eight through ten following the Generation Bio Merger Closing Date.

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Additionally, CVR holders are entitled to receipts associated with the Binney Lease (as discussed below), including the return of the Binney Lease security deposit of approximately $2.1 million, any interest accrued on the bank account associated with the Binney Lease, and a portion of the excess of any savings realized against estimates in connection with the Binney Lease payment obligations.

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The Company concluded that each of these CVR elements are contingent liabilities under ASC 450 and will be recognized when probable and reasonably estimable.

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Under the Generation Bio CVR Agreement, the CVR payments are adjusted for the excess and shortfall in the closing net cash, which is accounted for as a working capital adjustment to the purchase price and no contingent liability was recorded as of the acquisition date.

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The total purchase consideration for Generation Bio, as of February 9, 2026, was as follows (in thousands):

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In August 2018, Generation Bio entered into the Binney Lease for office and laboratory space located in Cambridge, Massachusetts, which was historically classified as an operating lease. The Binney Lease commenced in August 2018, with base rental payments beginning in April 2019 and ending in April 2029. On February 9, 2026, prior to the closing of the merger, the Binney Lease was terminated for a termination fee of $22.4 million.

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In March 2023, Generation Bio entered into the Moderna Collaboration and License Agreement, pursuant to which Generation Bio collaborated with Moderna on developing treatments for certain diseases by targeting delivery of nucleic acids to liver cells and certain cells outside of the liver. In April 2023, Moderna made an upfront payment to Generation Bio of $40.0 million, and prepaid research funding of $7.5 million. In addition, Generation Bio was eligible to receive up to $1.8 billion in milestone payments upon the achievement of specified development, regulatory, commercial, and sales milestone events, research term extension fees and exclusivity extension fees. Subject to reductions in specified circumstances, Generation Bio would also be entitled to receive tiered royalties ranging from mid-single-digits to low-double-digits. As part of the Generation Bio acquisition, the Company also acquired the Moderna Collaboration and License Agreement.

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The Generation Bio acquisition was accounted for as an asset acquisition under ASC 805 because the assets acquired did not meet the definition of a “business” under ASC 805. As such, the Company recognized the assets acquired and liabilities assumed based on the total purchase consideration on a relative fair value basis. The acquired assets primarily included cash and cash equivalents, restricted cash, receivables, prepaid expenses, and IP assets. The value of the acquired IP assets was reduced to zero because the fair value of the net assets acquired exceeded the initial consideration.

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The following table shows the allocation of the purchase consideration based on the relative fair value of assets acquired and liabilities assumed by the Company as of February 9, 2026 (in thousands):

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LAVA Acquisition

In November 2025, the Company completed the acquisition of LAVA for (i) $1.04 in cash per LAVA ordinary share and (ii) one non-transferable CVR per share. In-the-money LAVA options vested immediately upon closing of the initial tender offer and were entitled to (i) $1.04 less the exercise price per LAVA option in cash and (ii) one non-transferable CVR per option. Total purchase consideration was approximately $39.0 million as of the acquisition date.

Under the LAVA CVR Agreement, CVR holders are entitled to 75% of the net proceeds from ongoing and future collaborations related to the partnered programs with J&J and Pfizer over a 10-year period. As of March 31, 2026, the Company does not expect to receive any milestone or royalty payments under these partnered programs, and no contingent consideration was considered probable.

Under the LAVA CVR Agreement, CVR holders are also entitled to 75% of the net proceeds from the sale, transfer, license, assignment, or other divestiture of LAVA-1266. As of March 31, 2026, the Company has not yet sold or licensed LAVA-1266 and no contingent consideration was considered probable.

Additionally, CVR holders were entitled to 100% of the amount by which LAVA’s closing net cash exceeded the amount of closing net cash as determined by the LAVA Purchase Agreement, minus any permitted deductions. In March 2026, the Company distributed $2.1 million to the LAVA CVR holders representing the excess net cash received in the transaction. CVR holders are also entitled to 100% of the tax reserve in the amount of $6.3 million, plus $0.4 million in receipts after the excess net cash distribution, minus any permitted tax reserve matter expenses. As of March 31, 2026, the total LAVA CVR payment liability was estimated at $6.7 million.

Refer to Note 6 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, for additional information related to this acquisition.

HilleVax Acquisition

In September 2025, the Company completed the acquisition of HilleVax through a tender offer for (i) $1.95 in cash per share of HilleVax common stock and per RSU, plus (ii) one non-transferable CVR per share of HilleVax common stock and per RSU, resulting in total purchase consideration of approximately $105.3 million as of the acquisition date.

Under the HilleVax CVR Agreement, CVR holders are entitled to 90% of the net proceeds from the subsequent licensing or other disposition of HIL-216, if sold within two years of the merger and 100% of the unused funds in the related expense fund at the end of the two-year period. As of March 31, 2026, the Company has not yet sold or licensed HIL-216 and no contingent consideration under ASC 450 was considered probable.

As part of the HilleVax acquisition, the Company acquired the Boston Lease that expires on December 31, 2032, the Swiss Lease that expires on September 30, 2026 and an executed sublease agreement with a sublessee for a portion of Boston Lease premises. CVR holders are entitled to 100% of security deposit receipts associated with the Boston Lease. As of March 31, 2026, the Company had $40.2 million held in restricted cash to pay the Boston Lease obligations. If the Boston Lease is terminated, assigned, or subleased within twelve months of the HilleVax Merger Closing Date, 100% of the amount received from any subtenant will be distributed to CVR holders; thereafter 90% of the applicable receipts will be distributed to CVR holders. As of March 31, 2026 the CVR liability related to the return of the security deposit and the sublease payments was $5.6 million.

Under the HilleVax CVR Agreement, the CVR payments are adjusted for the excess and shortfall in the closing net cash. In December 2025, the Company recalculated the final closing net cash of HilleVax, and recognized a reduction to the contingent value rights liabilities – long-term in its consolidated balance sheet for the cash shortfall of $0.7 million, with the corresponding income recorded in other income, net in its consolidated statement of operations.

Refer to Note 6 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, for additional information related to this acquisition.

Turnstone Acquisition

In August 2025, the Company completed the acquisition of Turnstone through a tender offer for (i) $0.34 in cash per share of Turnstone common stock and per RSU, plus (ii) one non-transferable CVR per share of Turnstone common stock and per RSU, resulting in total purchase consideration of approximately $9.6 million as of the acquisition date.

Under the Turnstone CVR Agreement, CVR holders are entitled to up to 100% of the net proceeds from specified legacy Turnstone assets, including tax receivables and a lease security deposit. The consideration to be transferred under the Turnstone CVR Agreement is not contingent on any future event or conditions being met and represents a return of Turnstone’s legacy assets to the CVR holders. As a result, the CVR consideration of approximately $1.1 million is accounted for as a working capital adjustment to the purchase price and there is no contingent liability recorded. The Company will recognize any subsequent adjustments to CVR payment amounts in earnings. As of March 31, 2026, no subsequent adjustment was made to the CVR liability.

Refer to Note 6 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, for additional information related to this acquisition.

Mural Acquisition

In December 2025, the Company completed the acquisition of Mural for a cash price of $2.035 per Mural ordinary share and RSU, resulting in total purchase consideration of approximately $37.6 million as of the acquisition date.

Refer to Note 6 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2025, for additional information related to this acquisition.

Kinnate Acquisition

In April 2024, the Company completed the acquisition of Kinnate through a tender offer for $2.5879 per share plus CVRs, for a total purchase consideration of $126.4 million. As part of the merger, the Company acquired an IPR&D asset related to KIN-3248 (a Phase 1 clinical trial candidate) as well as several pre-clinical assets.

Under the Kinnate CVR Agreement, Kinnate CVR holders are entitled to 100% of the net proceeds of the $30.5 million potential milestone related to the sale of exarafenib to Pierre Fabre in February 2024. The Exarafenib milestone contingent consideration is accounted for as a derivative under ASC 815. As of March 31, 2026, the fair value of the Exarafenib milestone contingent consideration was $3.7 million, which had an estimated fair value of $3.6 million as of December 31, 2025.

The Company accounts for potential contingent consideration related to KIN-3248, KIN-8741, KIN-7136, and KIN-2524 as period expenses when incurred. In the second quarter of 2025, the Company sold KIN-3248, KIN-8741 and KIN-7136 to third parties and Kinnate CVR Holders are entitled to 85% of the net proceeds from future milestone and royalty payments associated with these sales. As of March 31, 2026, no contingent consideration associated with these sales were probable.

Pulmokine Acquisition

In November 2024, the Company acquired Pulmokine for $20.5 million to obtain an economic interest in seralutinib, a Phase 3 asset being studied in pulmonary arterial hypertension. The acquisition included an intangible asset related to seralutinib with an estimated useful life of 12 years. The Company recognized $0.5 million and $0.5 million of amortization expense for the three months ended March 31, 2026 and 2025, respectively.

In February 2026, Gossamer Bio announced topline results from the Phase 3 PROSERA clinical trial evaluating seralutinib for the treatment of pulmonary arterial hypertension. The trial did not meet its prespecified primary endpoint. Gossamer Bio plans to engage with regulatory authorities to discuss potential next steps for the seralutinib program. The Company evaluated the impact of this development on its seralutinib‑related assets. No impairment indicators were identified and no impairment was recorded during the three months ended March 31, 2026.

Contingent consideration related to the seralutinib asset could be payable subject to certain development and commercial milestones. As of March 31, 2026, there were no contract assets or contract liabilities related to this agreement and no revenue was recognized during the three months ended March 31, 2026 and 2025.