Orexigen obesity drug leads to 9.3 pct weight loss

By Deena Beasley

LOS ANGELES, Jan 8 (Reuters) - Orexigen Therapeutics Inc (OREX.O) said on Thursday the first of four late-stage trials found that obese patients treated with its experimental drug Contrave lost an average 9.3 percent of their weight, compared with 5.1 percent for patients given a placebo.

The company also said 26 percent of Contrave patients dropped out of the 793-patient trial due to side effects, compared with 13 percent of the placebo group.

Looking only at patients who completed the trial, the company said Contrave resulted in 11.5 percent weight loss, compared with 7.3 percent for patients given a placebo. On this basis, 80 percent of Contrave patients lost at least 5 percent of their baseline body weight, compared with 60 percent of the placebo group.

Contrave is a pill that combines the antidepressant Wellbutrin, known generically as bupropion, with a sustained- release version of naltrexone, an opioid antagonist used to treat alcoholism and other addictions.

Orexigen said the 56-week study, which included an intensive diet and exercise regimen, met its primary and secondary goals of a significant reduction in body weight, improvements in markers of cardiovascular risk and reductions in food craving measures.

The company said side effects seen in the trial were nausea, hives, anxiety, headache, constipation and dizziness.

Orexigen Chief Financial Officer Graham Cooper said the company still expects to file for U.S. regulatory approval of the drug toward the end of this year.

"Side effects and tolerability are going to be critical for the FDA (U.S. Food and Drug Administration). We had a very clean profile," he said.

The company expects to report results this summer from three other late-stage trials of Contrave that do not include diet and exercise programs. (Editing by Andre Grenon)