With that understanding, let's examine Qnexa, which as most obesity drug stock watchers know, combines two currently marketed medicines -- topiramate and phentermine -- into a single, weight-loss pill. Topiramate is an anticonvulsant. At higher doses than what's in Qnexa, topiramate is used to treat epileptic seizures and prevent migraine headaches.
After a recent meeting with FDA, Vivus disclosed that regulators are interested in seeing more safety data that could better define the incidence of birth defects, particularly cleft lips, in the babies born from women treated with topiramate. FDA's request for new safety data could delay Vivus' efforts to resubmit Qnexa for approval again after last fall's rejection.
Epilepsy and to a lesser extent migraine headaches are serious, acute conditions that affect a relatively smaller number of patients. Obesity is a chronic and non-fatal disease (at least directly) that affects millions of people, if not tens of millions of people. An obesity drug, if approved, could be very widely used. Women, most of childbearing age, will be particularly interested in obesity drugs.
That's the most likely reason for FDA's interest and concern about the topiramate component of Qnexa, even at lower doses. A teeny tiny risk of birth defects tied to topiramate use in a small number of epilepsy patients is acceptable; but the risk could become very much magnified if millions of obese women who may become pregnant start taking Qnexa.
Mike J. asks, "Follow you regularly, I appreciate your work. Did the Ariad Pharmaceuticals (ARIA - Get Report) move surprise you? I was thinking ponatinib would be more the future driver of this stock." Ariad shares 34% to $7.32 intraday on Jan. 28 following the release of positive results from the phase III study of ridaforolimus ('rida) in sarcoma. The stock has since settled back to around $6.76 as I write this column Thursday. Aria was a $2 stock in early 2010. Mike is correct in that a lot of investors are looking past 'rida and focusing more on ponatinib. 'Rida's clinical development and most of the drug's economics are controlled by Merck (MRK). The Mtor inhibitor class of cancer drugs to which 'rida belongs is competitive and the 'rida data in sarcoma -- while meeting the primary endpoint with statistical significance -- are not without concerns.