Orexigen Therapeutics Inc. said the U.S. Food and Drug Administration has extended its review of the company's investigational weight-loss treatment, delaying regulatory approval for the biopharmaceutical company's lead product candidate.

Shares plunged 15% to $5.80 in premarket trading.

The FDA has indicated that the review extension is needed in order to reach agreement on a post-marketing obligation related to the previously agreed-upon evaluation of cardiovascular outcomes for the drug.

The company's new drug-application resubmission package includes interim safety and cardiovascular outcomes data from the ongoing 8,900-patient study, Orexigen said.

Discussion around the package insert and other post-marketing obligations are ongoing, the company added.

"We are working expeditiously with the FDA to finalize the review," said Chief Executive Michael Narachi, adding that the company is encouraged by the high level of engagement with the FDA and is confident that it can reach agreement on the remaining post-marketing obligation.

For more details, go to: http://online.wsj.com/articles/orexigen-shares-tumble-as-fda-delays-approval-of-weight-loss-drug-contrave-1402485432