AstraZeneca backs Summit with $2 billion stake and cancer-drug collaboration

AstraZeneca agreed to invest $2 billion in Summit Therapeutics through convertible preferred shares, rather than buying the company outright. The shares imply a price of $18.36 per common share—an 18.6% premium to Summit’s closing price on the announcement day.

After the investment, AstraZeneca would hold rights equivalent to about 12% of Summit’s outstanding common stock, or roughly 10.6% on a fully diluted basis.

The investment is tied to clinical collaboration around ivonescimab, Summit’s cancer drug licensed from China’s Akeso. Ivonescimab targets PD-1 and VEGF, two pathways involved in cancer growth and immune evasion.

The companies plan to test ivonescimab with AstraZeneca’s antibody-drug conjugate sonesitatug vedotin in gastrointestinal cancers, and have outlined a broader, nonbinding program to study combinations with other AstraZeneca cancer medicines.

Each company retains development and commercial rights to its own medicines, and they will contribute their drugs and share costs for planned combination trials. The investment was reported as expected to close subject to customary conditions.