Orexigen says Contrave obesity trials meet goals

Orexigen Therapeutics Inc

said on Monday that three late-stage trials of its Contrave experimental weight-loss drug had met their goals, sending its shares up nearly 25 percent.

The San Diego-based company said the results supported its plan to file for U.S. regulatory approval in the first half of next year as they exceeded Food and Drug Administration benchmarks for clinically significant weight loss.

“The numbers indicate to us that the drug is both approvable and commercially meaningful,” Natixis Bleichroeder analyst Corey Davis said in a research note.

Orexigen said 48 percent of obese patients on a higher dose of Contrave lost at least 5 percent of their body weight, compared with 16.4 percent of those given a placebo in one trial. The same dose in another trial showed that 56.3 percent of patients achieved at least 5 percent weight loss vs. 17.1 percent of the placebo group.

“We practically tripled” the effectiveness, Orexigen Chief Executive Mike Narachi told Reuters.

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

Narachi said Orexigen had decided not to seek FDA approval for Contrave until next year because it needs time to compile a “quality” new drug application.

The one-year trials involved a total of about 3,800 patients.

At a lower dose, 39.5 percent of Contrave patients lost at least 5 percent of their weight. Orexigen said it would not pursue development of a third dose, the highest tested, since it did not show increased effectiveness.

One of the FDA guidelines for a weight loss drug is that there be a 5 percentage point difference in weight loss between the test drug and placebo.

At the main dose, patients in one trial had mean weight loss of 6.1 percent, compared with 1.3 percent on placebo - a percentage point difference of 4.8. In the second trial, the difference was 5.2 percentage points.

In January, Orexigen had announced results from its first late-stage trial of Contrave, showing just a 4.2 percent difference in absolute weight loss.

The company said patients generally tolerated Contrave well. Investigators attributed seven serious adverse events as possibly related to drug treatment, including one case of gallbladder inflammation and two seizures.

Obesity has become a full-fledged epidemic in the United States, but many drug treatments have failed. Companies like Pfizer Inc