Biopharmaceutical company AstraZeneca plc (STO:AZN) (LON:AZN) (NYSE:AZN) announced on Tuesday that it has agreed to invest USD2bn in newly issued equity in biopharmaceutical oncology company Summit Therapeutics Inc (NASDAQ:SMMT) to accelerate the development of ivonescimab, a PD-1/VEGF bispecific antibody, in combination with antibody drug conjugates (ADCs) across tumour types.

The companies will initially collaborate on clinical trials evaluating sonesitatug vedotin (Sone-Ve), a potential first-in-class Claudin-18.2-targeting ADC, with ivonescimab in gastrointestinal cancers.

Under the agreement, AstraZeneca and Summit will each provide their respective medicines and jointly fund trial costs, while retaining development and commercial rights to their own products.

The companies also signed a memorandum of understanding covering a planned global development programme combining ivonescimab with AstraZeneca's cancer medicines, including additional ADCs.

AstraZeneca recently reported positive high-level results from the CLARITY-Gastric01 trial of Sone-Ve in second-line and later Claudin18.2-positive advanced gastric cancer, with the results due to be presented at the European Society for Medical Oncology Congress 2026.

Ivonescimab, engineered by biopharmaceutical company Akeso Inc (HKEX: 9926), combines PD-1 blockade with VEGF inhibition and is approved for certain non-small cell lung cancer patients in China, while a US FDA application for EGFR-mutated NSCLC is under review. Summit holds exclusive rights to develop and commercialise ivonescimab in major territories outside China, with Akeso retaining rights in China and other regions.

AstraZeneca will receive approximately 109,000 preferred shares convertible into common stock at a 1:1,000 ratio, giving it rights equivalent to approximately 12.0% of Summit's outstanding common stock, or about 10.6% on a fully diluted basis. Closing of the investment is expected within one week.

Sone-Ve is continuing development in Phase III and Phase II trials across gastric, gastroesophageal junction, oesophageal adenocarcinoma, pancreatic and biliary tract cancers.