AstraZeneca invests $2 billion in Summit to advance ivonescimab

AstraZeneca agreed to invest $2 billion in newly issued convertible preferred shares of Summit Therapeutics, giving it rights equivalent to about 12% of Summit’s outstanding common stock (about 10.6% fully diluted). The purchase price equates to $18.36 per common share, an 18.6% premium to Summit’s closing price before the announcement.

The deal centers on ivonescimab, Summit’s bispecific antibody that blocks both PD-1, an immune-checkpoint target, and VEGF, a protein involved in tumor blood-vessel growth. Summit licensed the drug from China’s Akeso; it is approved in China for several non-small-cell lung cancer indications.

The companies will collaborate on trials pairing ivonescimab with AstraZeneca’s experimental ADC sonesitatug vedotin (Sone-Ve), which targets CLDN18.2. Initial studies are planned in gastrointestinal cancers, with both companies contributing their medicines and sharing trial costs.

A nonbinding memorandum of understanding outlines possible global development trials combining ivonescimab with other AstraZeneca cancer medicines, including additional ADCs. Each company retains rights to its own medicines.

The strategic bet is that combining a PD-1/VEGF bispecific with ADCs could broaden treatment options across tumor types. The proposed combinations still need clinical testing, so their safety and effectiveness are not yet established.