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Diet Drug Lorcaserin Safe, Effective, Study Finds


3 Star

Diet Drug Lorcaserin Safe, Effective, Study Finds

Our Review Summary

This story reports on a new diet drug that works in much the same way as the discredited and dangerous fen-phen pill that was pulled from the market in 1997.  The story reports that the drug appears to be safer than that drug and to be helping people lose weight.  But it felt a bit boosterish – especially without the perspective of a truly independent expert – and could have done a better job evaluating the evidence.


Why This Matters

Drug companies want a diet pill that works and that doesn’t kill people in the process. If they can create one that does, they will make a mountain of money. People who fight weight the old fashioned way — through diet and exercise — but can’t seem to make any headway could stand to benefit from some pharmaceutical help. The story says the race is on for FDA approval among several new competitors. The evidence that this drug is a big improvement, though, is shaky.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

There is no mention of costs. If the drug works similarly to fen-phen. Why not at least mention what that drug cost? If you have to take it twice a day for a year to see any results, what might that long term therapy add up to?

Does the story adequately quantify the benefits of the treatment/test/product/procedure?


See comments above about evaluating the evidence. We’ll rule this satisfactory because the story did a decent job of quantifying the likely magnitude of weight loss, both in terms of expected pounds lost, % who drop out, and % losing 5% or 10% body weight.

Does the story adequately explain/quantify the harms of the intervention?

A mixed bag, for which we’ll give the story the benefit of the doubt. 

Stronger points:

  • The story starts out with some good framing, by explaining, "The drug lorcaserin works on the serotonin receptor — the same appetite-controlling hormone targeted by the notorious drug fenfluramine, the "fen" component of combination medication fen-phen. Fenfluramine was taken off the market in 1997 after being linked to potentially life-threatening heart valve problems."
  • The story mentions the most common side effects and that the study examined valve issues and found no problem.

Weaker points: 

  • It would have been nice to know if the quality of the study was felt to be good enough to definitively determine that the drug is indeed safe.
  • What drove 45% of the drug takers out of the study? No explanation.
  • We didn’t need the marketing spin from the manufacturer: "But lorcaserin is far more selective than the drug fenfluramine and much safer, its manufacturer says, because it specifically targets the serotonin receptor associated with hunger while having no impact on the heart."

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

It makes several stabs at evaluating the evidence, but it lacked absolute numbers to give people a true sense of the improvement. It starts out by saying, "About half the dieters who took lorcaserin for a year in the study lost at least 5% of their body weight, compared to 20% of dieters who took a placebo pill." That sounds like an amazing result. Even better, "About one in five lorcaserin users lost 10% or more of their body weight, compared to one out of 14 placebo users." And, in case you were wondering whether those pounds would reappear quickly, the story says, "People who continued on the drug for two years were able to maintain their weight loss better than those switched to placebo after one year, researcher Steven R. Smith, MD, of the Florida Hospital and the Sanford-Burnham Institute tells WebMD." But much lower in the story, the caveats start coming. "All the participants were counseled about diet and exercise." But, presumably, some were already better at choosing the right foods and following an exercise regimen than others. How did the study control for this? This is the most dramatic fact, "By the end of year one, 55% of the patients in the placebo group and 45% of those taking the diet drug had dropped out of the study." What did that do to the absolute difference in the number of people who lost more weight? Because the outside voices in this story are weak, it’s hard to know how big of a deal this drug really is. 


Does the story commit disease-mongering?


This is one of the high points of this story compared to others. Instead of framing the story as "new hope in the war on obesity," it focuses more narrowly on the research. A line about obesity prevalence would have been nice.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

It identifies conflicts in some cases, but there is no truly independent expert source quoted in the story – something that was badly needed. 

Does the story compare the new approach with existing alternatives?

Not Satisfactory

The story misses one huge point. How does this drug do when compared to diet and exercise? The story mentions that the drug is not as effective as two existing drugs, but doesn’t compare it to other weight loss treatments. If people walked 30 minutes a day and ate a balanced diet, would they lose more than 12 pounds on average in a year’s time? (Ask that Subway pitchman.)

Does the story establish the availability of the treatment/test/product/procedure?


The story makes it clear that the drug is still in trials although it could have done a better job explaining how far it has come and what steps it still has to take to win approval.

Does the story establish the true novelty of the approach?


The story places this drug into a sort of horse race of diet drugs galloping toward approval by the FDA. It does a pretty good job explaining why this one is different than the others, but it doesn’t do a great job of explaining how this works in comparison to the OTC drugs out there now.

Does the story appear to rely solely or largely on a news release?


The story does not rely on a news release, but it also doesn’t take the extra effort of having unbiased sources evaluate the drug.

Total Score: 6 of 10 Satisfactory


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