Orexigen says trial of 2nd obesity drug meets goal

* Placebo-adjusted weight loss of 6.1 percent

* No differences in cognitive function, depression

* Company looking for single partner

LOS ANGELES, Sept 30 (Reuters) - Orexigen Therapeutics Inc (OREX.O) said on Wednesday that a mid-stage trial of Empatic, the second obesity drug being developed by the company, met its main goal of demonstrating significant weight loss.

Side effects included headache, insomnia and hives, but there were no meaningful differences between the drug and placebo on measures of cognitive function, depression or thoughts of suicide, the company said.

The drop-out rate for all arms of the trial was about 30 percent.

Empatic combines the antidepressant Wellbutrin, known generically as bupropion, with anti-seizure drug zonisamide, which can cause birth defects and altered cognitive function.

Orexigen said the 729-patient trial found that 60.4 percent of obese people given the highest dose of the drug lost at least 5 percent of their body weight, compared with 14.7 percent of patients given a placebo.

The 24-week trial also found that patients treated with Empatic had mean weight loss of 7.5 percent, compared to 1.4 percent for the placebo group -- a percentage point difference of 6.1.

The results exceeded U.S. Food and Drug Administration guidelines for approvable weight control drugs.

Weight loss averaged about 10 percent for patients who completed the trial, said Chief Executive Michael Narachi.

"The weight loss trajectory is quite steep, continuing downward with no evidence of a plateau," he said.

Orexigen, based in San Diego, said it plans to meet the FDA to discuss the Empatic data and define a pivotal-stage trial. Narachi told Reuters the "ideal scenario" would be to fund further trials with money from a development partner.

Orexigen still plans to file in the first half of next year for regulatory approval of Contrave, an experimental pill that combines bupropion with a sustained-release version of naltrexone, an opioid blocker used to treat alcoholism and other addictions.

"We would put both drugs in the same partnership," the CEO said, although he declined to set a time frame for such talks.

Since zonisamide should not be taken by women of child- bearing age, Empatic will likely be targeted at a more narrow patient population than Contrave, Narachi said.

"Empatic will probably be used more toward later stage, or more severe patients," he added. (Reporting by Deena Beasley; editing by Andre Grenon)