In the diet-medication sweepstakes, we have a winner. While all five drugs approved by the Food & Drug Administration for weight loss best a placebo in helping patients lose weight, a drug known commercially as Qsymia — a combination of the drugs phentermine and topiramate — most consistently prompted patients taking it for a year to shed a good chunk of their excess poundage.
Over the past four years, the FDA has, with great deliberation, approved four new drugs for weight loss. While some Americans are using the new medications — which go by the commercial names Belviq, Qsymia, Contrave and Saxenda — many patients continue to use Orlistat, now an over-the-counter weight-loss drug first approved by the FDA in 1999 and known commercially as Alli.
The drug companies that make and market the new medications have spent dearly to persuade physicians to prescribe them to obese Americans as the weight of most of the country’s population has continued to climb.
When assessed and approved for marketing by the FDA, the new prescription weight-loss medications were required to show they were more effective than a placebo in prompting the loss of more than 5% of a person’s body weight. Most also were approved on the condition that their sponsors conduct additional clinical trials of safety and effectiveness of the medication.
The new research, published Tuesday in the journal JAMA, collects and analyzes the findings of 28 clinical trials in which one or more of the diet drugs were tested for a year or longer against either a placebo or another of the medications. All told, the new “meta-analysis” — essentially a study of studies — reflects the experiences of 28,019 trial participants, nearly three-quarters of them women. Half of the recruits had a BMI greater than 36.1 — well into the obese range — and half had a lower BMI.
Qsymia, the first of the four new weight-loss drugs to be approved, fared best in promoting the loss of 5% of body weight in patients taking it. A median of 75% of those taking Qsymia lost 5% of their body weight, while a median of 63% of participants taking Saxenda and 55% of those taking Contrave did. A median of 49% of participants taking Belviq and 44% of those taking the over-the-counter medication Alli succeeded in losing 5% of their body weight in the trials. A median of 23% of those on a placebo pill lost 5% of their weight.
On average, participants who took Qsymia lost 8.8 kilograms — just short of 20 pounds — after a year. The average weight loss was 5.3 kilograms (about 11.5 pounds) for those on Saxenda, 5 kilograms (about 11 pounds) for those on Contrave, 3.2 kilograms (about 7 pounds) for those on Belviq and 2.6 kilograms (about 5.5 pounds) for those on Orlistat.
The new study said that physicians and their patients have a range of considerations in choosing a weight-loss medication — and, in the medications available, a range of strengths and weaknesses. Saxenda, which started its pharmaceutical life as a diabetes drug, may be the best choice for obese patients with metabolic abnormality. Contrave — a drug that combines the antidepressant bupropion and the anti-addiction drug naltrexone — may risk complications for patients with substance addiction issues.
“Given the differences in safety, efficacy and response to therapy, the ideal approach to weight loss should be highly individualized,” the authors wrote.
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