Vanda Pharmaceuticals reports positive Phase III results for Hetlioz

Vanda Pharmaceuticals reported that its Phase III study of Hetlioz (tasimelteon) met the primary endpoint for treating delayed sleep-wake phase disorder (DSWPD). In the 28-day randomized, double-blind trial, patients receiving a 20 mg daily dose fell asleep an average of 42.5 minutes earlier, compared to a 5.4-minute advance for the placebo group, resulting in a placebo-adjusted difference of 37.1 minutes.

An exploratory analysis showed that 60 percent of the tasimelteon recipients achieved a sleep-onset advance of at least 30 minutes, compared to 15 percent of the placebo group. Vanda stated that the safety profile was consistent with the existing Hetlioz label and reported no new safety signals. The company intends to discuss these results with the U.S. Food and Drug Administration (FDA) and seek a supplemental application for this third indication.

Despite the positive clinical readout, Vanda shares experienced volatility. While the stock saw an after-hours surge following the announcement, it faced downward pressure during subsequent trading. Investors expressed caution regarding the small trial size—which analyzed 20 patients per arm—and previous FDA rejections of the drug for other uses, such as jet lag.