The pending approval by the FDA of Vivus’ Qnexa for the drug treatment of obesity, which may happen on July 17, 2012, follows on the heels of the approval received by Arena Pharmaceuticals for its drug, Lorcaserin (marketed as Belviq). However, the difference with Qnexa is that, unlike Lorcaserin, which is really a single drug designed to fight obesity by targeting serotonin to produce “satiety”, Qnexa is one of a number of forthcoming combination drugs. Combination drugs like Qnexa and Contrave (Orexigen Therapeutics) are ultimately expected to represent the largest share of the obesity treatment market including not only drug but drugs and devices (see Worldwide Obesity Treatment Market Outlook).
Combination drugs represent a new opportunity for existing drugs often developed for other purposes. Qnexa is a combination of amphetamine and an anticonvulsant, while Contrave is a combination of an antidepressant and an anticonvulsant. Of course, the manufacturers of these drug combinations are specifically seeking FDA approval for their use as treatments in obesity. A negative perception associated with combination drugs for obesity exists as a result of the unapproved (i.e., “off-label”) use of Fen-Phen, which was a combination of two anorectics, Fenfluramine and Phentermine. While Phentermine was not shown to have any significant side effects, Fenfluramine was linked to major heart valve problems and led to claims against its manufacturer, Wyeth (later part of Pfizer), who was forced pay out a $21 billion settlement.
The enormous potential of an obesity drug, which has the potential to treat upwards of 30% of western populations who are obese and even a share of the nearly 50% of such populations who are overweight, was clearly behind the Fen-Phen debacle and has cast a certain pall over obesity drug market outlooks that was further darkened by the FDA’s prior denial of Arena’s Lorcaserin, Vivus’ Qnexa and Orexigen’s Contrave. However, manufacturers and the FDA alike redoubled their efforts to understand potential complications through additional testing to isolate and contraindicate uses that are high risk and the result is that Lorcaserin has been recently approved, Qnexa may be approved this week and Contrave has actually accelerated the end of its trial, with a prospect of approval in late 2013.
Prior to the approval of Arena’s Lorcaserin, the last obesity drug to gain approval GlaxoSmithKline’s Xenical over 13 years ago.
For a global analysis of obesity treatments, see the comprehensive MedMarket Diligence Report #S835, “Products, Technologies and Markets Worldwide for the Clinical Management of Obesity, 2011-2019”.