Orexigen Therapeutics, whose experimental obesity pill Contrave was rejected by the FDA in January, said it's laying off 23 employees, or 40% of its staff. The company expects to incur first-quarter restructuring charges of about $2.6 million in connection with one-time employee termination costs, including severance and other benefits. Contrave was the third weight-loss drug rejected by FDA in the past year. In 2010 the agency gave thumbs down to Vivus' Qnexa and Arena's lorcaserin. Contrave was to be marketed in the US with Takeda, and in December an FDA advisory panel had recommended approving the drug. But a complete response letter conditioned Contrave approval on conducting a new study to rule out risk of heart attack or stroke, and analysts say such a trial could take years.