Thursday, October 1, 2026

AstraZeneca invests $2bn in Summit to advance ADC combinations

AstraZeneca is expanding its oncology strategy through a strategic equity investment in Summit Therapeutics. The company said on 28 September 2026 that it will buy newly issued Summit preferred stock worth $2 billion. The investment is intended to support development of ivonescimab in combination with antibody drug conjugates, or ADCs, across tumour types.

Ivonescimab is a bispecific antibody designed to target both PD-1 and VEGF. It was engineered by Akeso. Summit holds exclusive development and commercialisation rights in major territories outside China, while Akeso retains rights in China and certain other regions.

Clinical collaboration in gastrointestinal cancer

Alongside the investment, AstraZeneca and Summit have agreed a clinical collaboration. The first programme will evaluate sonesitatug vedotin, also known as Sone-Ve, together with ivonescimab in gastrointestinal cancers. The companies said the studies are expected to begin imminently.

Sone-Ve is a Claudin 18.2-directed ADC carrying an MMAE payload. AstraZeneca is already studying the candidate in several gastrointestinal cancer trials. Under the collaboration, each company will provide its own medicine for the planned combination trials and share trial costs. Development and commercial rights for the respective assets will remain unchanged.

Broader programme under discussion

The two companies have also signed a memorandum of understanding covering a potential global development programme. That programme would combine ivonescimab with cancer medicines from AstraZeneca’s portfolio, including additional ADCs.

The agreement fits AstraZeneca’s focus on broadening the use of ADCs within oncology combination regimens. Bispecific PD-1 and VEGF approaches are being developed in several settings, including lung, breast and gastrointestinal cancers.

Trial data and development status

AstraZeneca recently reported positive high-level results from the Phase III CLARITY-Gastric01 study of Sone-Ve. The trial tested Sone-Ve in second-line and later Claudin 18.2-positive advanced gastric cancer. According to the company, the study showed a statistically significant and clinically meaningful overall survival benefit compared with investigator’s choice of therapy. Results are scheduled for presentation at the ESMO Congress 2026 in a Presidential Symposium.

Ivonescimab is approved in China for certain patients with non-small cell lung cancer. In the US, the FDA is reviewing a Biologics License Application for EGFR-mutated non-small cell lung cancer. The therapy is also being tested in Phase III trials in non-small cell lung cancer, small cell lung cancer, biliary tract cancer, bladder cancer, triple-negative breast cancer, head and neck squamous cell carcinoma, colorectal cancer and pancreatic cancer.

Stake equal to about 12 percent

AstraZeneca will purchase about 109,000 newly issued Summit preferred shares. These are convertible into common stock at a ratio of 1 to 1,000. After completion, AstraZeneca will hold rights equivalent to approximately 12.0 percent of Summit’s outstanding common stock, or about 10.6 percent on a fully diluted basis.

The preferred stock investment is expected to close within one week. Any future conversion into common stock would be subject to customary regulatory clearances.