Arcus & Summit Partner on Kidney Cancer

On July 22, Arcus Biosciences, Inc. and Summit Therapeutics Inc. announced a significant clinical trial collaboration. This partnership will combine Arcus's investigational HIF-2α inhibitor, casdatifan, with Summit's investigational PD-1/VEGF bispecific antibody, ivonescimab.

The primary goal of this new study is to assess the safety and efficacy of this combination therapy. The focus is specifically on treating clear cell renal cell carcinoma (ccRCC), including cases of first-line metastatic disease. Arcus's CEO, Terry Rosen, emphasized the potential for this combination to establish a well-tolerated, TKI-sparing regimen.

Under the terms of their agreement, Summit Therapeutics will provide ivonescimab, while Arcus will sponsor and conduct the study as part of its existing ARC-20 platform. Both companies will share the associated costs and retain commercial rights to their respective drugs. Initial data from this collaborative trial is projected to be available by mid-2027.

In parallel, Arcus Biosciences also entered into a clinical supply pact with AVEO Oncology on July 22, further supporting its broader casdatifan strategy.

Financially, as of Q2 2026, both Arcus and Summit maintain strong liquidity. However, Arcus demonstrates more robust revenue generation and a longer operating runway. Arcus reported $41 million in Q2 2026 revenue and a net loss of $91 million, with cash reserves extending into the second half of 2028. Summit Therapeutics reported no product revenue and a net loss of $215.7 million, with its cash position bolstered by significant ATM equity facility funding.

Arcus's bull case is centered on casdatifan's potential as a backbone HIF-2α inhibitor, with aggressive program expansion preceding pivotal clinical readouts in October. The bear case for Arcus includes potential revenue fluctuations due to partner milestone payments and reduced pipeline diversification following the wind-down of certain trials.