After reviewing stunning Phase 2 results for flu preventative CD388, the FDA proactively asked Cidara to expand its Phase 3 trial to include all individuals over 65. This highly unusual step, where a regulator suggests broadening a study's scope, indicates immense confidence in the drug's potential public health impact.
Cidara's core technology attaches potent small-molecule drugs to an inert antibody fragment. This design extends a drug's presence in the body while preventing it from entering human cells. This reduces the off-target toxicities common in high-dose treatments, a principle the company is applying to both its flu preventative and cancer therapies.
An unexpectedly severe flu season, the worst in 15 years, created ideal conditions for Cidara's Phase 2b clinical trial. The high infection rate allowed the 5,000-participant study to demonstrate statistically significant efficacy, an outcome researchers hadn't anticipated would be possible at that stage of development.
Unlike vaccines requiring a patient's immune system to generate antibodies, Cidara's CD388 is a long-acting antiviral drug. It provides direct, passive protection by targeting a non-mutating part of the flu virus, making it effective for the millions of people with weakened immune systems who don't respond well to traditional shots.