RCUS Stock Down on Decision to Discontinue GILD Partnered Study

Core Insights - Arcus Biosciences, Inc. (RCUS) shares fell 14.4% after the discontinuation of the STAR-221 study due to futility in improving overall survival (OS) in upper gastrointestinal cancers [1][7] - The STAR-221 study was a collaboration with Gilead Sciences, Inc. (GILD) and evaluated a combination of domvanalimab and chemotherapy against nivolumab plus chemotherapy [2][4] Study Discontinuation - The Independent Data Monitoring Committee recommended discontinuing the STAR-221 study based on interim analysis data showing no improvement in OS [2][5] - The domvanalimab combination demonstrated a safety profile comparable to nivolumab plus chemotherapy, with no new safety findings [5] Future Focus - Arcus will shift its focus to the development of casdatifan, a potential best-in-class HIF-2a inhibitor, which has shown robust single-agent activity in late-line clear cell renal cell carcinoma [8][9] - The company retains full rights to casdatifan worldwide, except in Japan and certain Asian territories [10] Oncology Portfolio - Arcus's oncology portfolio includes quemliclustat, a CD73 inhibitor, which is in late-stage PRISM-1 study for pancreatic cancer, with results expected in 2027 [11] - The company is also developing five programs targeting inflammatory and autoimmune diseases, with a small molecule targeting MRGPRX2 expected to enter clinical trials in 2026 [12] Financial Outlook - Arcus expects to fund its operations until at least the second half of 2028, supported by approximately $1 billion in cash and investments [13]