Merck drug results in weight loss, side effects

By Deena Beasley

LOS ANGELES (Reuters) - Obese patients treated with a low dose of Merck & Co Inc's (MRK.N: Quote, Profile, Research, Stock Buzz) experimental drug taranabant lost a significant amount of weight, but there were side effects, according to interim results from a pivotal trial released by the company on Monday.

After one year, and in combination with diet and exercise, patients given a 2 mg dose of the drug lost an average of 14.5 pounds (6.6 kg), compared with 5.7 pounds for the placebo group.

Patients on the 2 mg pill ended up weighing, on average, 4 percent less than patients on placebo and weight leveled off after 36 weeks.

Higher doses resulted in greater weight loss, but Merck has discontinued study of doses above 2 mg because they increased the incidence of side effects like nausea, irritability and depression without much more benefit in terms of pounds shed.

Taranabant belongs to the same family of medicines as rimonabant, a Sanofi-Aventis SA (SASY.PA: Quote, Profile, Research, Stock Buzz) drug rejected by U.S. regulators last year after it was linked to suicidal thoughts and depression. Both drugs work by blocking cannabinoid receptors in the brain, the same receptors that make people hungry when smoking marijuana.

"We believe we have a different profile ... We didn't see the same neurological effects in preclinical trials that they did," said Dr. John Amatruda, vice president of Merck's metabolism clinical research.

FDA FILING EXPECTED THIS YEAR

He said Merck intends to file this year for U.S. regulatory approval of taranabant, but declined to confirm whether the application would seek a label for weight loss.