October 19, 2025 — Leads & Copy — Taiho Pharmaceutical Co., Ltd. and Arcus Biosciences, Inc. (NYSE:RCUS) have announced that Taiho has exercised its option to develop and commercialize casdatifan, an investigational small molecule HIF-2α inhibitor, in Japan and certain other territories in Asia (excluding mainland China).
The decision is based on a 2017 option and license agreement between the two companies, marking the fifth option exercise by Taiho to an Arcus program.
Taiho will make an option exercise payment, as well as additional payments upon achievement of clinical, regulatory and commercialization milestones. If any products from the program are approved, Taiho will pay royalties on net sales of such products.
Arcus is currently conducting a global Phase 3 study, PEAK-1, comparing casdatifan and a VEGFR-targeted tyrosine kinase inhibitor (TKI) combination therapy to monotherapy using a VEGFR-targeted TKI alone in patients with clear cell renal cell carcinoma (ccRCC). Japan is expected to participate in the study starting in the first half of 2026.
Casdatifan is a small-molecule inhibitor of HIF-2α, which is involved in kidney cancer development. Kidney cancer incidence is rising worldwide, with ccRCC being the most common type in adults.
The 2017 agreement between Taiho and Arcus has granted Taiho exclusive rights to five Arcus programs in Japan and certain other Asian territories. These programs include casdatifan, etrumadenant, zimberelimab, domvanalimab, and quemliclustat.
Taiho Pharmaceutical, a subsidiary of Otsuka Holdings Co., Ltd., focuses on oncology and immune-related diseases. Arcus Biosciences is a clinical-stage biopharmaceutical company developing molecules and combination therapies for cancer.
Source: Taiho Pharmaceutical Co., Ltd.
