Shares of Kiniksa Pharmaceuticals Ltd. KNSA, -1.28% tumbled 15.1% in premarket trading Tuesday, after the biopharmaceutical company said a Phase 3 trial of mavrilimumab for treatment of COVID-19-related acute respiratory syndrome (ARDS) failed to meet the primary efficacy endpoint. The company said a total of 582 patients in the Phase 3 trial were randomized to receive a single intravenous dose of mavrilimumab or placebo, and the primary efficacy endpoint was for proportion of patients alive and free of mechanical ventilation at Day 29. “The Phase 3 study of mavrilimumab in COVID-19-related ARDS did not provide the expected outcome, however we are proud of our efforts to help patients in need during this unprecedented time,” said Kiniksa Chief Executive Sanj Patel. “We continue to believe in the potential broad utility of mavrilimumab and are evaluating next steps for the molecule.” The stock has rallied 7.1% over the past three months through Monday, while the iShares Biotechnology ETF IBB, +0.52% has dropped 5.4% and the S&P 500 SPX, +0.16% has gained 10.1%.
