Placebo Response Trips Up Harmony Biosciences’ Fragile X Drug in Late-Stage Phase 3 Trial
Harmony Biosciences announced that its Phase 3 RECONNECT study of ZYN002, a transdermal cannabidiol gel for Fragile X syndrome, failed to meet its primary endpoint—improvement in social avoidance135.
The failure was attributed to a higher than expected placebo response rate, which made it difficult to detect a drug-specific benefit135.
The study was randomized, double-blind, and placebo-controlled, enrolling 215 patients aged between 3 and under 30 years, with an 18-week treatment period1.
Elevated placebo responses have been a known issue in Fragile X syndrome trials, particularly affecting caregiver-rated outcomes and confounding efficacy signals2.
Despite the setback, Harmony will continue its late-stage drug development pipeline, with further Phase 3 trials planned for other indications1.
Sources:
1. https://trial.medpath.com/news/efd1991c98f97142/harmony-biosciences-zyn002-phase-3-trial-fails-to-meet-primary-endpoint-in-fragile-x-syndrome
2. https://pmc.ncbi.nlm.nih.gov/articles/PMC7563217/
3. https://insights.citeline.com/scrip/r-and-d/clinical-trials/harmonys-zyn002-is-latest-drug-to-flunk-in-fragile-x-syndrome-N7FC3HEHMVF6PELSOD6ZJVSTPI/