Orexigen Therapeutics Inc. said it reached an agreement with the U.S. Food and Drug Administration on the design and analysis of a cardiovascular safety trial for the company’s investigational obesity drug Contrave.

The trial is the last known hurdle for Contrave before it can hit the market. With the FDA’s “Special Protocol Assessment” agreement in place, San Diego-based Orexigen said it can launch the trial late in the second quarter.

Contrave already completed phase 3 clinical trials and Orexigen submitted the drug for FDA approval in March 2010. But in January 2011, the FDA told Orexigen that it could not approve Contrave without a massive study to eliminate certain heart risks. Orexigen put drug development on hold, saying such a study would be excessive and prohibitively expensive.

Things changed last September, when Orexigen and the FDA agreed to a “reasonably sized” study involving about 10,000 patients. Under the new plan, the drug could gain approval in 2014, Orexigen said.

“A few months ago, we received detailed written correspondence from the FDA’s Director of the Office of New Drugs that identified a clear and feasible path forward for this important potential obesity therapy,” Orexigen President and CEO Michael Narachi said, in a Feb. 6 company statement.

He said Orexigen made “rapid progress” working out the details of the clinical trial with the FDA’s Division of Metabolic and Endocrinologic Products.

Contrave is a combination of two well-established drugs, naltrexone and bupropion. It works by reducing appetite, boosting metabolism and addressing the reward system in the brain that causes food cravings, according to Orexigen.

Shares of Orexigen, which trade on Nasdaq under the symbol OREX, jumped 18 percent on Feb. 6 to a high of $3.25.

— Kelly Quigley