A previously rejected weight loss pill won anoverwhelming endorsement from public healthadvisers Wednesday, raising hopes that the drugfrom Vivus Inc. could become the first new anti-obesity medication to reach the U.S. market inmore than a decade.
The Food and Drug Administration has rejectedthree weight loss pills in the last two years,including Vivus' pill Qnexa, due to safetyconcerns. Experts agree new weight loss drugs areneeded to treat an estimated 75 million obeseadults in the U.S., but the string of rejectionshas raised questions of whether any pharmaceuticaltreatment is safe enough to win approval.
At a public meeting Wednesday, an FDA panel ofoutside physicians voted 20-2 in favor of theweight loss drug from Vivus, setting the stage fora potential comeback for a drug that has beenplagued by safety questions since it was firstsubmitted to the agency in 2010.
Nearly all the panelists backed the drug due toits impressive weight loss results, with mostpatients losing nearly 10 percent of their overallweight after a year on the drug. But the groupstressed that the drugmaker must be required toconduct a large, follow-up study of the pill'seffects on the heart. Studies of Qnexa show itraises heart rate and causes heart palpitations, alongtime concern with diet pills over the years.The group of experts said it is still unclear ifthose side effects lead to heart attack and moreserious cardiovascular problems.
"The potential benefits of this medication seem totrump the side effects, but in truth, only timewill tell," said Dr. Kenneth Burman of theWashington Hospital Center.
The FDA is not required to follow the advice ofits panels, though it often does. A final decisionon the drug is expected by mid-April.
In a key question, the physicians said Vivus couldconduct the cardiovascular safety study after FDAapproval. A requirement to conduct the study aheadof market approval would cost the company millionsof dollars and take at least three more years.
"There is an urgent need for better pharmacologicoptions for individual patients with obesity,"said Dr. Elaine Morrato, of the University ofColorado. "I believe Qnexa demonstrated ameaningful efficacy benefit and that there areconsequences to not treating obesity."
Vivus, based in Mountain View, Calif., is one ofthree small drugmakers racing to bring the firstnew prescription weight loss drug to market inmore than a decade. In the past two years the Foodand Drug Administration has rejected pills fromall three: Arena Pharmaceuticals Inc., OrexigenTherapeutics Inc. and Vivus. All three companiesare in the process of resubmitting their products.
The FDA rejected Qnexa in October 2010, citingnumerous side effects including elevated heartrate, psychiatric problems and birth defects.Vivus has resubmitted the drug with additionalfollow-up information on safety, hoping for a morefavorable ruling.
Vivus President Peter Tam said the overwhelmingpanel vote Wednesday indicates doctors recognizethe urgent need for effective weight loss drugs.
"Right now there aren't any good treatments outthere besides dieting and bariatric surgery --clearly there's a huge gap," Tam said.
With U.S. obesity rates nearing 35 percent amongadults, doctors and public health officials saynew weight-loss therapies are desperately needed.And even a modestly effective drug could haveblockbuster potential. Analysts expect a newweight loss pill to garner at least 10 millionusers within a few years.
Qnexa is a combination of two older drugs: theamphetamine phentermine, which is approved forshort-term weight loss, and topiramate, an anti-seizure and anti-migraine drug sold by Johnson &Johnson as Topamax. Phentermine helps suppressappetite, while topiramate is supposed to makepatients feel more satiated.
Along with heart safety, panelists raised concernsabout potential birth defects in women who becomepregnant while taking Qnexa: topiramate is knownto more than double the risk of birth defects.
There were 34 pregnancies among 3,386 womenenrolled in Vivus' studies of Qnexa, despiteprecautions to make sure women used contraception.An FDA expert on birth defects estimated therewould be five babies born with a cleft lip defectfor every 1,000 women who became pregnant whiletaking Qnexa.
If approved, FDA scientists said they wouldrequire Vivus to train prescribers to educatepatients on the pregnancy risks of Qnexa. The drugwould only be available from 10 mail-orderpharmacies.
Qnexa's other ingredient, phentermine, was onehalf of the dangerous fen-phen combination, aweight loss treatment pushed by doctors that wasnever approved by the FDA. The regimen was linkedto heart-valve damage and lung problems in thelate 1990s, and the FDA forced drugmaker Wyeth towithdraw two versions of its drug fenfluramine.
Fen-phen is just one example in the decadeslonghistory of failed weight loss drugs, which havecontinued to pile up in recent years.
Four years ago Sanofi-Aventis SA discontinuedstudies of its highly anticipated pill Acompliadue to psychiatric side effects, includingdepression and suicidal thoughts. In 2010, AbbottLaboratories withdrew its drug Meridia after astudy showed it increased heart attack and stroke.The drug won approval in 1997 in the wake of therecall of fenfluramine but never achievedwidespread use due to modest weight loss andsafety concerns. Only 100,000 prescriptions werewritten in the U.S. during Meridia's last full-year on the market.
Currently there is just one prescription drug onthe market for long-term weight loss: Roche'sXenical, which is sold over the counter as alli byGlaxoSmithKline. The drug is not widely usedbecause of modest weight loss results andunpleasant side effects, including gas anddiarrhea.