The Phase III study of CD388, a non-vaccine preventative of seasonal flu, has been accelerated by six months, biotechnology company Cidara Therapeutics has announced. 

The planned Phase III study will be a global, multicentre, randomised, double-blind, placebo-controlled study to evaluate the safety and efficacy of a single 450-milligram dose of CD388. The drug will be administered via subcutaneous injection at the beginning of the flu season. 

The acceleration of the Phase III trial follows a meeting between Cidara Therapeutics and the US Food and Drug Administration (FDA). Based on FDA feedback, the study population will be expanded to include adults over 65 years of age with no specific co-morbidities, as well as people over 12 years of age with high-risk comorbidities or immune compromised status. The expansion increases the initial number of patients potentially eligible to receive CD388 from approximately 50 million to well over 100 million people in the US. 

The company intends to begin enrolment by the end of September 2025 in the Northern Hemisphere with continuation into the spring of 2026 in the Southern Hemisphere, with a target enrolment of 6,000 subjects. This represents a six-month acceleration from the prior plan to initiate the Phase III study in the spring of 2026 in the Southern Hemisphere. 

Adults over 65 to be included 

The study will include an interim analysis following the Northern Hemisphere flu season, assessing the trial size, powering assumptions and determining enrolment for the Southern Hemisphere flu season. 

“The FDA’s input on our Phase III study design was invaluable and we welcome the opportunity to expand the trial to include adults over 65 years of age who are among the most vulnerable to serious complications from influenza,” said Jeffrey Stein, President and Chief Executive Officer of Cidara.

“Older adults receive less protection from vaccines because the immune system naturally declines with age. Including them in our trial not only addresses a critical unmet need but will also accelerate enrolment. With the success of our financing earlier this summer, we believe that our planned Phase III development programme will be fully funded through completion, and we look forward to building on the strong Phase IIb NAVIGATE results as we advance CD388 toward becoming a universal, non-vaccine, long-acting option for flu prevention.” 

 

Bruno Quinney, Content Team, DDW