Anxious to win FDA approval for its Qnexa diet pill, Vivus (VVUS) has come up with an unsual fallback position to overcome safety issues that have so far scuttled agency endorsement. If the results of a planned teratogenicity study are inadequate to win over regulators, the beleaguered little drugmaker plans to seek a limited indication. Very limited. This would involve allowing docs to prescribe the diet pill to "only men and women of non-child bearing potential" (read here).
This might seem counterintuitive. After all, diet pills are widely sought by countless women who are still capable of conceiving. For instance, Leerink Swann analyst Steve Yoo estimates in an investor note this morning that about 50 percent of the "likely market could fall into the women of childbearing age." And more women than men are believed to be willing to pop a diet pill. Yoo notes that in Qnexa Phase III trials, 70 percent to 83 percent were women, "which is typical for obesity therapy."
In other words, Vivus appears willing to settle for the "something is better than nothing" theory of salvaging a project to generate revenue. Of course, Vivus may not get to this desperate stage if the teratogenicity study offers useful results. This retrospective observational study, you may recall, is being undertaken to examine the incidence of oral clefts in babies whose moms took topiramate, which is one component of its Qnexa drug; the other is phentermine, the surviving half of fen-phen (see here).
On the other hand, if the teratogenicity study is a flop, Vivus may have a hard time winning approval, or at least monitoring usage. Once a diet pill is approved, demand is certain to rise. And with demand, comes all manner of efforts to obtain a drug, regardless of restrictions. Even if a risk management plan of some sort is required, many docs are unlikely to want to be put in the uncomfortable position of ensuring patients are incapable of conceiving. Hence, the sales potential would be, well, slim.
Hat tip to Adam at The Street.