Pharma BD Deal Intelligence
Arcturus gets its vaccine portfolio back, and the commercialisation problem with it
Full analysis, sources & comparables →Arcturus Therapeutics and CSL Seqirus mutually terminated their vaccine collaboration agreement under a termination and settlement agreement entered into on August 3, 2026 and disclosed publicly with Arcturus's second-quarter 2026 results on August 7, 2026. Arcturus regained strategic control of its self-amplifying mRNA vaccine portfolio, including the approved COVID-19 vaccine KOSTAIVE and its programs for seasonal influenza, pandemic influenza, respiratory syncytial virus and Epstein-Barr virus, subject to ongoing arrangements with Meiji Seika Pharma for the Northern Hemisphere 2026-2027 season in Japan. Arcturus received a one-time cash payment of $12.0 million from CSL Seqirus and was released from a liability and from repayment of an R&D credit with an aggregate value of approximately $16.0 million, for an effective value of roughly $28 million. The settlement also resolved the pending arbitration relating to a European regulatory approval milestone payment.
Arcturus gets its vaccine portfolio back, and the commercialisation problem with it
Assessment window: 5yr post-close.
Note: this deal's 5-year assessment window closes Aug 2031; the outcome grade above is a projected assessment, not yet finalized.
COVID-19 has settled into an endemic seasonal-respiratory pattern in the United States. CDC's Center for Forecasting and Outbreak Analytics reported that the 2025-2026 season peaked in the week ending 3 January 2026 at a hospitalisation rate of 2.0 per 100,000, within 20% of the combined peak of the prior season and consistent with the pre-season outlook. Ensemble forecasts put new laboratory-confirmed COVID-19 hospital admissions at approximately 2,800 (range 1,600-5,000) for the week ending 29 August 2026. Declining and increasingly seasonal demand has compressed COVID-19 vaccine revenue and left the category dominated by two conventional modRNA franchises, Comirnaty and Spikevax, which raises the bar for a differentiated entrant.
This is a reversion, not an acquisition: Arcturus recovered strategic control of its entire sa-mRNA vaccine portfolio and was paid to do so. The settlement removes a large-pharma partner from KOSTAIVE and the influenza, RSV and EBV programs, and simultaneously resolves arbitration over a disputed European regulatory approval milestone. The economics are modest and one-directional - $12.0M cash plus release from roughly $16.0M of liability and R&D-credit repayment - so the real question is whether a company of Arcturus's scale can commercialise an approved COVID-19 vaccine against Pfizer/BioNTech and Moderna without a partner, in a market whose seasonal volumes are contracting.
The parties entered into a termination and settlement agreement mutually terminating the CSL Collaboration Agreement, returning KOSTAIVE and the seasonal influenza, pandemic influenza, RSV and EBV vaccine programs to Arcturus and resolving the arbitration over a European regulatory approval milestone payment.
Announcing second-quarter 2026 results, Arcturus disclosed it received a one-time $12.0M cash payment from CSL Seqirus and was released from a liability and from repayment of an R&D credit with an aggregate value of approximately $16.0M, an effective value of roughly $28M.
| Deal | Year | Value | Outcome |
|---|---|---|---|
| Arcturus Therapeutics, Inc. / CSL Seqirus (CSL Limited) (this deal) | 2026 | $28M | 100 |
| Genentech, Inc. (Roche Group) / Duality Biologics (Suzhou) Co. Ltd. | 2026 | $1.0B | 100 |
| Genentech, Inc. (Roche Group) / Hanmi Pharmaceutical Co. Ltd. | 2026 | $2.3B | 100 |
| Servier Pharmaceuticals LLC / Day One Biopharmaceuticals Inc. | 2026 | $2.5B | 75 |
| Servier / Edgewise Therapeutics, Inc. | 2026 | $2.6B | 75 |
| AstraZeneca PLC / Dizal Pharmaceutical Co., Ltd | 2026 | $1.5B | 73 |
| Travere Therapeutics, Inc. / Everest Medicines Limited | 2026 | $1.1B | 72 |
← Browse all deals · How we score deals
More: 2026 deals