Vanda Pharmaceuticals Inc. (Nasdaq: VNDA) announced that its Phase III clinical study of VQW-765, an experimental treatment for social anxiety disorder, did not meet its primary endpoint.

The study, designated VP-VQW-765-3201, was a multicenter, randomized, double-blind, placebo-controlled trial conducted at approximately 30 U.S. clinical sites. It enrolled 546 adults between 18 and 65 years of age with a current diagnosis of social anxiety disorder. Participants received a single oral dose of VQW-765 or placebo before undergoing the standardized Trier Social Stress Test, a psychosocial stress test involving a simulated public speaking scenario.

The primary endpoint measured distress levels in female participants during the performance phase of the test, using the Subjective Units of Distress Scale. Female participants who received VQW-765 scored 65.6 compared to 66.0 for those who received placebo, a difference that was not statistically significant (p=0.8899). The study also failed to meet its key secondary endpoint in the combined male and female population, where VQW-765 participants scored 64.7 versus 63.8 for placebo (p=0.6605).

The Phase III trial was designed to confirm findings from an earlier Phase II study in which participants who received VQW-765 reported numerically lower stress levels than those who received placebo. The Phase III results did not replicate those findings.

"We are disappointed that Study 3201 did not confirm the earlier Phase II findings for VQW-765 in patients with social anxiety disorder," said Mihael H. Polymeropoulos, M.D., President, CEO and Chairman of Vanda Pharmaceuticals.

The company said the VQW-765 program is on hold pending further analysis of the full dataset. VQW-765, formerly known as AQW-051, was licensed to Vanda from Novartis. The drug was reported to be safe and well tolerated in the study, consistent with prior trials.