Regeneron stock drops double digits on oncology trial failure

Shares of Regeneron Pharmaceuticals (REGN) fell about 12% on Monday, making the biotech company the worst-performing stock in the S&P 500 after its experimental melanoma treatment failed a pivotal late-stage clinical trial. The sharp selloff followed Regeneron's announcement that its high-dose fianlimab and cemiplimab combination failed to significantly outperform Merck's Keytruda in a Phase 3 study involving patients with previously untreated metastatic melanoma.