AstraZeneca to Invest $2B in Summit Therapeutics for 12% Stake, Ivonescimab Cancer Drug Alliance

AstraZeneca announced on Sept. 29, 2026, a $2 billion equity investment in Summit Therapeutics (SMMT), securing a roughly 12% stake through convertible preferred stock. The U.S.-listed biotech's shares jumped about 17% in early trading following the disclosure. The deal includes a broad alliance to test Summit's ivonescimab, a PD-1/VEGF bispecific antibody, with multiple AstraZeneca oncology drugs, initially pairing it with the antibody-drug conjugate Sone-Ve in gastrointestinal tumors. The companies will jointly fund development while retaining rights to their respective medicines. Summit holds U.S., Canadian, European and Japanese rights to ivonescimab via a $500 million 2022 licensing deal with China's Akeso. AstraZeneca gains exposure to the most advanced clinical-stage candidate among PD-1/VEGF blockers, a class drawing deals from Pfizer, Merck, AbbVie and Bristol Myers Squibb. Jefferies analyst Michael Leuchten said the investment gives AstraZeneca a "seat at the table" without major risk, should ongoing global trials validate the approach. Summit shares climbed on the news.