Despite Phase 3 Trial Halt, U.S. Biotech Stocks Surge by Over $300 Billion in a Day

Arcus Biosciences Inc. (NYSE: RCUS), a U.S. cancer‐drug developer, closed at $24.71 on April 21, up 8.66% from the prior trading day. Its market capitalization stands at about $3.1 billion—roughly ₩4.6 trillion at an exchange rate of ₩1,480 per U.S. dollar—and rose by approximately $290 million (about ₩440 billion) in a single session.

The day before, Arcus announced that its Phase III STAR-121 trial evaluating the anti-TIGIT antibody domvanalimab in combination therapy for lung cancer patients had been halted for futility. It also disclosed that its option-collaboration period with Gilead Sciences will expire on July 14, 2026. Despite an initial sell-off, investors perceived the company’s pipeline as still diversified and saw the pullback as a buying opportunity, driving the stock’s rebound.

Headquartered in Hayward, California, Arcus Biosciences is a clinical-stage oncology company with several late-stage assets, including the immune-checkpoint–targeting antibody domvanalimab and a HIF-2α inhibitor for renal cancer. Since 2020, Arcus has maintained a ten-year strategic alliance with Gilead to co-develop immuno-oncology combination therapies; Gilead holds roughly a 33% ownership stake in Arcus.