FDA Rejects Vivus’s Obesity Drug Qnexa
As was widely expected, the Food and Drug Administration has rejected Vivus's experimental weight-loss drug Qnexa, making it the second obesity drug in a week to be turned away by the agency. On Saturday, Arena Pharmaceuticals said it had received a complete response letter (CRL) for its obesity drug Lorqess (lorcaserin), based largely on worries that the drug caused tumors in rats.
The biggest concerns in Vivus' CRL were around birth defects and cardiovascular risk. Vivus had already submitted a plan to keep tabs on pregnancy and birth defects after the drug was approved, and the agency seems to want to continue evolving that monitoring strategy. FDA also wants data showing that the drug's propensity to raise heart rate does not lead to an increased risk of cardiovascular events. If eventually approved, FDA said Qnexa would be considered a controlled substance along the lines of Xanax and Valium.
The good news is that Vivus says it doesn't believe it needs to generate any new clinical data to fulfill FDA's requests. Further, the agency didn't ask any questions about the drug's ability to induce weight loss. In a conference call with investors this morning, Vivus CEO Leland Wilson said it would take the company about six weeks to prepare its response to the CRL, and depending on how FDA classifies the application, the drug could be reviewed two-to-six months after the submission. Shares of Vivus were up over 30% in pre-market trading.
As a reminder, Qnexa is the only drug in the three-way obesity race to lack a partner. Arena has licensed Lorqess to Esai, and Takeda has bought into Orexigen's Contrave.
Qnexa is a combination of two drugs that are already FDA-approved: it’s a combination of topiramate, an antiseizure medication that enhances feelings of fullness, and phentermine, the “Phen” part of Fen-Phen, which was not linked to heart valve defects.
When FDA posted briefing documents in advance of the Qnexa panel meeting, we learned that the agency had no problem with Qnexa's ability to help patients lose weight. But the committee had safety concerns in five areas: effects on pregnant women, cardiovascular risks, psychiatric events, cognitive events, and metabolic acidosis. Last July, an FDA panel thought that Vivus needed more long-term safety data on Qnexa and voted not to recommend the drug for approval. (Seven panel members voted for approval but nine recommended against approval.)