Orexigen Therapeutics, Inc., a La Jolla-based pharmaceutical firm, received some discouraging news on Jan. 31, when the Food and Drug Administration rejected the company’s new diet pill, Contrave. In a response to Orexigen’s application for approval, the FDA issued a letter, stating that the company must conduct a “randomized, double-blind, placebo-controlled trial of sufficient size and duration to demonstrate that the risk of major adverse cardiovascular events in overweight and obese subjects does not adversely affect the drug’s benefit-risk profile.” Company executives indicated that though they had not expected outright approval of the drug, they were surprised by the high expectations of the administration. “We are surprised and extremely disappointed with the Agency’s request in light of the extensive discussion and resulting vote on this topic at the Dec. 7 Advisory Committee meeting,” Michael Narachi, President and CEO of Orexigen said in a recent statement. “We plan to work closely with the Agency to gain more information to determine the appropriate next steps regarding the Contrave application.” Contrave was initially submitted for U.S. regulatory approval in March 2010 based on multiple clinical trials that evaluated the drug in more than 4,500 patients. During a conference call with stock analysts, Narachi said that the letter had not specified the size of the study requested by the FDA. “It’s pretty clear that these (types of) trials are fairly large and take fairly long to conduct,” he said.