Safety Data On Vivus’s Qnexa Doesn’t Cut It For FDA Panel-UPDATED

You have to feel for the FDA's Endocrinologic and Metabolic Drugs Advisory Committee this week. They'd just finished the Avandia slog, but there was no rest for the weary. No, instead, they got to sink their teeth into the first of the potential new obesity drugs, Vivus' Qnexa. In a vote that signals safety is king in the obesity drug realm, Qnexa got a thumbs down from the panel this afternoon. The panel was split, with 7 members recommending that FDA should approve the drug and 9 recommending against approval. The panel's take home message was that a lack of safety data led to their decision. Several journalists live-blogged the panel session. Here are the two play-by-plays I followed: Lisa LaMotta, Minyanville Adam Feuerstein, TheStreet This decision comes after what seemed like an optimistic week for Vivus. On Tuesday, when FDA released its briefing documents about Qnexa, media reports on the data suggested that even though the agency's review focused on safety, it didn't look like safety would be a dealbreaker. In a note to investors, Leerink Swann analyst Steve Yoo wrote, "Overall, we believe the language in the FDA briefing documents to be fairly benign, but the FDA is requesting a pregancy category X label that would include contraindication in pregnant women and a warning/ precaution for females of childbearing potential." At today's panel, as expected, nobody really dwelled on Qnexa's efficacy. But Vivus faced a lot of questions about safety, especially about the effects of Qnexa during a pregnancy. During clinical trials, 13 women on Qnexa gave birth, and none of the babies had birth defects. Because Qnexa is likely to be an appealing option for women of reproductive age if it's approved, panelists were concerned that more data are needed to make sure Qnexa is safe during pregnancy. That's because one of the components of Qnexa is topiramate, an epilepsy drug that is known to carry a risk of birth defects. What complicates things is that the dose of topiramate in Qnexa is lower than the dose used for treating epilepsy. It's also lower than the doses used in studies that suggested topiramate carries a risk of birth defects. The panel also discussed the other four safety concerns mentioned in the briefing documents: cardiovascular risks psychiatric events cognitive events metabolic acidosis But at the end of the day, panelists who voted 'no' felt like more long-term safety data was in order. From Feuerstein's liveblog:
one of the "no" votes says obesity is a chronic disease, so tell me what happens to patients as they stay on the medication for years.
The deadline for FDA to make a decision on Qnexa is October 28. So it might be a while before we hear the final word. Vivus has time to come up with more safety data. Trading on Vivus's shares was stopped today because of the hearing but will start again tomorrow. Shares for Arena and Orexigen, the other two big players in the obesity drug race, fell late today. It was a bit of a rollercoaster day for Arena, since shares soared earlier today because of new lorcaserin data published in the New England Journal of Medicine. UPDATE July 16: Yesterday evening Vivus responded to the news in a conference call. In an accompanying press release, the company noted that "The vote from the Endocrinologic and Metabolic Drugs Advisory Committee is a recommendation. The FDA will take the Committee's recommendation into consideration during its review of the current application and will make a determination. The FDA may or may not follow the Committee's recommendation." Leland Wilson, Vivus' CEO, said in the release "We appreciate the Advisory Committee's recognition of obesity as a significant health crisis, and the challenges associated with the treatment of this disease." "We are disappointed with the Advisory Committee's vote. While the final vote was close, and we are encouraged that the Committee recognized the efficacy demonstrated in the QNEXA clinical trials, we will work closely with the FDA leading up to our October 28, 2010 PDUFA date to address the labeling and safety questions raised during today's proceedings. We remain committed to patients living with obesity and weight-related disease."

Author: Carmen Drahl

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  1. People want an easy fix to diet issues, which makes the dietary supplement market grow tremendously. Lorcasrin makes claims to a much higher probability of weight loss than most pills you will find on the market. A 50% chance of weight loss is not enough for making me take out an installment loan and buy this pill; but for many that is a gamble worth taking. Although this pill has not yet received FDA approval, it is in the process; and the chances seem to be good that it will get the go ahead from them. One of the biggest concerns with this new pill is how new it is, the long term effects definitely won’t be seen for years.

  2. Hey johnathanv- I agree with you about long-term effects. That’ll be important, especially since a lot of folks who take this drug might be otherwise healthy. I’m thinking many won’t be anywhere near obese- they’ll ask their doc for a prescription so they can lose a few pounds. Something else that hasn’t been tested but that may see use in the future- the combination of lorcaserin and phentermine. Keep in mind that lorcaserin was developed to be a safer version of fenfluramine, which when you combined it with phentermine gave you the infamous drug combo Phen-Fen. Phentermine was not found to be problematic, and lorcaserin seems to be safe, but we don’t know about the effects of a combo yet.

    I am not sure that the 50% chance of weight loss number tells you the whole story. The official press release from the company that makes lorcaserin describes the study in more detail. Everybody in the study had diet and exercise counseling. Not everybody who started the study stayed in it the whole time, and others dropped out because of side effects.