The FDA had announced on September 16 that the highly anticipated weight loss drug, lorcaserin, was rejected by a panel of experts in a vote of 9 to 5. On October 22 the drug's maker announced it had been rejected. High hopes had been attached to the drug — particularly on Wall Street — as it was touted to provide significant weight loss with few side effects. This is the second of three weight loss drugs the FDA has ruled on this year (the first being Qnexa, which was recently rejected).
The FDA panel voted against the drug because of potential side effects that had not been revealed until mid-September. Namely, lab rats who were given the drug developed tumors.
Unable to decide on the drug’s fate themselves, the FDA had turned the matter over to a panel of experts, the Endocrinologic and Metabolic Drugs Advisory Committee. Now that group has also withheld approval. The FDA panel voted against the drug because of potential side effects that had not been revealed until mid-September. Namely, lab rats who were given the drug developed tumors. The panel said this side effect was concerning enough to outweigh the weight loss benefit, which was sparse enough that it did not meet FDA criteria for a diet pill.
The drug is thought to work by affecting serotonin, a neurotransmitter in the brain thought to play a role in appetite and how the body metabolizes food.