Cidara Therapeutics reported positive top-line Phase 2b results for its long-acting antiviral biologic CD-388, demonstrating significant efficacy in preventing seasonal influenza in healthy, unvaccinated adults aged 18 to 64. The single-dose therapy met all primary and secondary endpoints, including sustained prevention efficacy up to 28 weeks, and was well-tolerated without dose-limiting adverse events. The data have sparked a substantial increase in Cidara’s stock price and a planned FDA meeting to discuss Phase 3 trial design, positioning CD-388 as a potential alternative to traditional flu vaccines with a multibillion-dollar market opportunity.