Long-Acting experimental Influenza Drug Shows Strong Protection, may outperform Vaccines: Study

A new long-acting influenza drug by Cidara Therapeutics demonstrated up to 76% protection against symptomatic flu in a phase 2b trial, lasting for about six months with a single dose. The results suggest it could outperform traditional flu vaccines, and data has been submitted to the FDA for review.

Cidara Therapeutics, a biotechnology company applying its proprietary Cloudbreak® platform to develop drug-Fc conjugate (DFC) therapeutics, has announced positive topline results from its randomized, double-blind, placebo-controlled Phase 2b NAVIGATE trial evaluating CD388 for the prevention of seasonal influenza in healthy unvaccinated adults aged 18 to 64. The study met its primary endpoint, demonstrating a statistically significant prevention efficacy (PE) for each of three dose groups in individuals who received a single dose of CD388 at the beginning of the flu season and were evaluated for laboratory and clinically confirmed influenza over 24 weeks. The study also met all secondary endpoints, including efficacy at 37.8 and 37.2 degree Celsius temperature thresholds, as well as maintenance of PE up to 28 weeks with statistical significance. Over the same period, CD388 was well-tolerated at all doses with no unexpected dose-limiting treatment-emergent adverse events observed.

Safety and tolerability data were similar in all arms with no safety signals observed. No drug-related serious adverse events were observed, and treatment-emergent adverse events showed no dose-dependent pattern between CD388 and placebo groups. Injection site reaction rates were similar across all CD388 dose groups and placebo.

Cidara expects to present additional results from the NAVIGATE trial at upcoming scientific conferences in 2025.

“Results such as these are unprecedented in influenza and support our confidence in the potential of CD388 to offer robust, once-per-season protection against influenza A and B,” said Jeffrey Stein, Ph.D., president and chief executive officer of Cidara. “As a long-acting antiviral drug, CD388 was designed to provide once per season protection against all strains of influenza in all people, irrespective of immune status. These results provide us with continued conviction in the remarkable opportunity CD388 presents to deliver broad influenza protection. We thank all of our collaborating partners for their dedication and hard work to reach this milestone. Cidara is grateful to the individuals whose participation helped us to generate these important results.”

Nicole Davarpanah, M.D., J.D., chief medical officer of Cidara added, “The statistically significant and clinically meaningful results shown with CD388 mark a potential breakthrough for patients and the future of influenza prevention. These Phase 2b results support the potential of CD388 to be a highly effective and well-tolerated seasonal prophylactic for high-risk individuals, such as those with compromised immune systems or those at a heightened risk of severe illness due to underlying health conditions. We look forward to engaging with the FDA and expanding on these results in our planned Phase 3 trial.”

Cidara has submitted an end of Phase 2 meeting request to the FDA to review the Phase 2b results and further discuss the Phase 3 trial design and start time.