Thumbs down on weight loss pill

[Guest guest]

http://www.latimes.com/news/health/la-heb-qnexa-20100715,0,4013603.story

An independent panel of FDA advisors on Thursday voted

narrowly<http://www.fda.gov/AdvisoryCommittees/WhatsNew/default.htm>to

recommend against approval of a proposed new weight-loss drug, Qnexa.

The

drug agency, which is expected to make an up or down decision on the drug by

October, is not bound by the advisory panel's 7-9 recommendation against

approval. But the panel's views generally weigh heavily in the agency's

final decision.

In the race among pharmaceutical companies to win market approval for a new

generation of

obesity<http://www.latimes.com/topic/health/physical-conditions/obesity-HEDAI000\

0057.topic>drugs,

Qnexa is the most recent to make it to the crucial FDA advisory panel

stage. It's the first of a trio of new candidate drugs to do so. (The

others,

lorcaserin<http://www.latimes.com/news/health/la-heb-weightdrug-20100715%2C0%2C4\

842768.story>and

Contrave <http://www.orexigen.com/candidates/candidates_contrave.php>, are

to come before an FDA advisory panel in September and December,

respectively.)

Qnexa, developed by the biotechnology firm

Vivus<http://www.latimes.com/topic/economy-business-finance/vivus-incorporated-O\

RCRP016407.topic>of

Mountain View, Calif., combines

phentermine <http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682187.html>,

a stimulant that has been used in the past for weight

loss<http://www.latimes.com/topic/health/physical-conditions/weight-loss-HEPHC00\

00055.topic>,

and topiramate,<http://www.nlm.nih.gov/medlineplus/druginfo/meds/a697012.html>a

medication that has been approved to treat seizure disorders and

migraines<http://www.latimes.com/topic/health/physical-conditions/migraine-HEPHC\

0000027.topic>

..

Other candidate weight-loss drugs — most recently

rimonabant<http://www.fda.gov/ohrms/dockets/ac/07/briefing/2007-4306b1-fda-backg\

rounder.pdf>—

have failed to make it over the hurdle the FDA set in 2007 to guide

its

consideration of future weight-loss drug candidates.

The FDA is walking a tightrope in its deliberations on weight-loss drugs.

With two-thirds of American adults

<http://www.cdc.gov/obesity/data/trends.html>overweight<http://www.latimes.com/t\

opic/health/physical-conditions/overweight-HEDAI0000052.topic>or

obese and a resulting public health disaster looming, the agency

urgently

needs to approve a medication that can help Americans lose weight and keep

it off. At the same time, the agency is acutely aware that any weight-loss

product it approves will probably be broadly marketed and taken by a

potentially vast population of patients already beset by obesity-related

conditions. Given those circumstances, any hint of a drug-related safety

problem could quickly mushroom.

The FDA's staff

report<http://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterial\

s/Drugs/EndocrinologicandMetabolicDrugsAdvisoryCommittee/UCM218824.pdf>on

Qnexa, posted this week to the FDA's website, reflected the delicate

balance the agency is striking. Looking at Qnexa's performance in two

clinical trials sponsored by Vivus, the FDA's staff found a somewhat

effective weight-loss drug with a worrying array of side effects.

Qnexa's performance as a weight-loss drug just got over the bar the FDA has

set for effectiveness in weight-loss drugs. The staff report declared Qnexa

" efficacious for weight loss. " But it noted that the different rates at

which subjects on a placebo drug and those on Qnexa lost 5% of their body

weight " were of nominal statistical significance. " Among those on the

mid-dose and highest doses of Qnexa, 62% and 69%, respectively, lost 5% of

their body weight.

And the drug's safety record during clinical trials — particularly at high

doses, at which it's most effective — will clearly raise questions about how

it would affect a broad population of overweight and obese patients, if it's

approved for broad use.

Twice as many subjects taking the highest dose of Qnexa withdrew from

clinical trials, citing side effects, than those taking the placebo. At high

doses, subjects reported such side effects as palpitations, anxiety,

thoughts of suicide and difficulty in concentrating at far higher rates than

those taking a placebo. Four heart

attacks<http://www.latimes.com/topic/health/physical-conditions/heart-attack-HEI\

SY000062.topic>were

reported among the roughly 2,280 subjects being treated with Qnexa,

but

none was reported among those taking the placebo.

Finally, the FDA's staff expressed concern over the safety of Qnexa for

women who might become pregnant, given that one of the drug's components has

been shown to cause birth defects. In the clinical trials the staff

reviewed, women on birth control taking Qnexa appeared more likely than

similar women taking placebo to get pregnant. That finding prompted the

FDA's staff to wonder whether Qnexa might render some prescription

birth-control methods less effective.

Copyright © 2010, The Los Angeles Times <http://www.latimes.com/>

--

Ortiz, MS, RD

" I plan on living forever - so far so good "

" Cause of obesity, heart disease and cancer: Look at the end of your fork "

A Forum on Health Communication

http://weblogs.jomc.unc.edu/ihc/