Recently, we at AdverseEvents, a health analytics company, compared for the very first time the postmarket safety profiles of 3 new obesity drugs: Belviq (lorcaserin hydrochloride, Arena/Eisai), Contrave (bupropion hydrochloride/naltrexone hydrochloride, Orexigen Therapeutics), and Qsymia (phentermine hydrochloride/topiramate, Vivus). Using recently obtained real-world adverse event data from a Freedom of Information Act request, we estimated the potential downstream medical costs for patients using these treatments as a basis for understanding each drug’s respective safety profile. What we found was surprising. Despite the nervousness about the safety of these drugs preapproval and managed care’s general reluctance to pay for them, postmarketing data are showing a relatively benign safety profile for all 3, particularly lorcaserin.
Having been on the market for over 2 and a half years, lorcaserin is showing the safest downstream medical cost profile with an estimated cost per prescription of $2.03 compared to $2.60 for bupropion/naltrexone and $3.31 for phentermine/topiramate. The main drivers of downstream costs for lorcaserin that are currently on the drug’s label include heart valve incompetence issues as well as psychiatric issues such as suicidal ideation. Issues not on the label that are also driving downstream costs include atrial fibrillation and loss of consciousness. Although these risks are indeed serious, the reporting rates have been low. For instance, only 3 valve incompetence issues have been reported so far, which is an estimated incidence rate of roughly 3 cases for every 100,000 patients exposed.
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Although the analysis for bupropion/naltrexone is preliminary because it was only approved in September 2014, we found that it has a slightly riskier safety profile than lorcaserin based on the serious adverse events reported so far. The main drivers of the downstream costs for bupropion/naltrexone that are on the label include convulsion, suicidal ideation, and angioedema. The nonlabeled adverse events driving downstream costs include deafness, pancreatitis, and cerebrovascular accident.
Approved around the same time as lorcaserin, phentermine/topiramate is showing the riskiest safety profile of the 3 obesity drugs with a cost per prescription of $3.31. The main drivers of the downstream costs for phentermine/topiramate that are already labeled include nephrolithiasis (kidney stones), angle-closure glaucoma, as well as mental impairment and suicidal ideation. The nonlabeled adverse events driving the downstream costs include deafness and pneumonia as well as vascular issues such as ischemic cardiomyopathy and intracranial aneurysm.