Strong data for Merck & Co's taranabant

US drug major Merck & Co says that patients who took low doses of its drug candidate taranabant saw significant weight loss, according to results from a mid-stage trial. In the 12-week, 535-patient study, the cannabinoid 1 receptor inverse agonist induced statistically-significant weight loss versus placebo in obese subjects over the entire range of evaluated doses (0.5mg, 2mg, 4mg and 6mg once per day; p < 0.001).

The data, which were published in the January 8 issue of the journal Cell Metabolism, show that the agent was associated with dose-related increased incidence of clinical adverse events, including mild-to-moderate gastrointestinal and psychiatric effects. Lead study author Steven Heymsfield, of Merck Research Laboraties, is hopeful that taranabant will escape the problems that have beset Sanofi-Aventis' obesity drug Acomplia (rimonabant). The predicted blockbuster was the first CB1R drug to market but was denied US approval over concerns that it increased the risk of depression and suicide (Marketletters passim). As the Merck drug was effective at relatively low doses, it might not cause the psychiatric effects of rimonabant, he said.