AstraZeneca has agreed to invest $2bn in newly issued equity in Summit Therapeutics to develop combination therapies using the bispecific antibody ivonescimab and antibody-drug conjugates (ADCs) across multiple tumour types.
Under the transaction, AstraZeneca will acquire around 109,000 preferred shares convertible into Summit common stock at a 1:1,000 ratio.
This will provide an estimated 12% stake in the outstanding common stock, or 10.6% on a fully diluted basis.
Alongside the equity investment, the two companies agreed to a clinical collaboration to assess ivonescimab in combination with sonesitatug vedotin (Sone-Ve), an ADC targeting CLDN18.2 with a monomethyl auristatin E payload.
The partners plan to begin clinical trials in gastrointestinal cancers imminently, with each party supplying its respective candidate, sharing clinical trial expenditures, and retaining independent commercial and development rights.
Concurrently, a non-binding memorandum of understanding (MoU) was executed to pursue a wider global programme evaluating ivonescimab with additional AstraZeneca oncology therapies.
Ivonescimab is a bispecific antibody engineered by Akeso and blocks both programmed cell death protein 1 (PD-1) and vascular endothelial growth factor (VEGF).
Summit holds exclusive development and commercialisation rights for Ivonescimab outside China, while Akeso retains rights in China and other regions.
The therapy is approved in China for certain non-small cell lung cancer (NSCLC) patients, and a biologics license application (BLA) for EGFR-mutated NSCLC is being reviewed by the US Food and Drug Administration (FDA).
AstraZeneca oncology haematology R&D executive vice-president Susan Galbraith said: “A core pillar of our oncology strategy is to broaden the reach of our ADC portfolio as the backbone of treatment across tumour types with combinations alongside next-generation immunotherapies.
“Bispecifics targeting PD-1 and VEGF are rapidly advancing in development and have the potential to improve on current immunotherapies, particularly in lung, breast and gastrointestinal cancers.
“This opportunity to combine ivonescimab with AstraZeneca’s ADC portfolio, including with Sone-Ve, could enable new regimens that raise the bar for patients with cancer across the treatment landscape."
AstraZeneca licensed Sone-Ve globally from KYM Biosciences in March 2023.
Earlier this month, the FDA granted accelerated approval to AstraZeneca’s Etcamah (camizestrant), used with a cyclin-dependent kinase (CDK) 4/6 inhibitor (abemaciclib, palbociclib or ribociclib), for breast cancer.
