Key points from article :
Cidara Therapeutics, a biotech company based in San Diego, has developed a new antiviral drug called CD388 to prevent seasonal flu. In a Phase 2b study, researchers tested this drug on healthy adults aged 18 to 64. Participants were split into groups to receive one of three doses — 150 mg, 300 mg, or 450 mg — or a placebo.
The main goal was to see if the drug could prevent flu-like illness over 24 weeks. The highest dose showed 76% effectiveness, while the lower doses also performed well, crossing 50%, which experts consider very encouraging. The drug combines a strong antiviral component, zanamivir, with a protein fragment, designed to provide long-lasting protection with just one shot per season.
Unlike traditional flu vaccines, this therapy could serve as an alternative for people who cannot take vaccines due to allergies or other health issues. No serious or unexpected side effects were observed, suggesting it is safe for further testing.
Cidara now plans to discuss Phase 3 trial designs with the FDA and hopes this treatment could become a new option for flu prevention. The study results were announced in June 2025 and reported by BioPharma Dive, sparking major interest in the biotech community.
