Silenor approval path clarified, narrowed
Executive Summary
Somaxon will have to re-analyze the clinical data on its insomnia agent Silenor (doxepin) to see whether it can re-submit the application for chronic insomnia. After meeting FDA to discuss the "complete response" letter issued in late February, Somaxon is conducting additional analyses of its clinical data on the durability of sleep maintenance and, if they meet FDA's requirements, will include that in a re-submission. The complete response letter raised both efficacy issues and QT prolongation, but FDA has accepted the ECG study already submitted (1"The Pink Sheet" DAILY, Feb. 27, 2009). Regarding the efficacy issues, which Somaxon had hoped to further elucidate with FDA, the company said FDA was clear that for chronic insomnia, objective and subjective efficacy must be shown in adult and elderly populations at both the beginning of treatment and on a persistent basis, defined as at least one month. The firm also said it will not pursue approval of a claim that Silenor improves sleep onset, and will abandon the 1 mg dose (the lowest submitted)