The Newest FDA-Approved Obesity Drug Is Also the Oldest

Novo Nordisk on Tuesday gained Food and Drug Administration approval for its obesity drug Saxenda. While that is not the feat it would have beena few years ago,Novo Nordisk can boast that itsobesity drug was approved on its first try, unlike Arena Pharmaceuticals' Belviq, VIVUS' Qsymia, and Orexigen's Contrave.

Of course, the FDA went two months beyond its internal deadline before approving the drug, so it's not like the agency was anxious to approve Saxenda.

CompetitionFortunately for the current obesity drugs, Saxenda isn't much of a competition. Unlike Belviq, Qsymia, and Contrave, which are pills, Saxenda has to be injected.

If Saxenda had amazing efficacy, obese patients might be willing to take the injectionrather than pop a pill; but with placebo-adjusted weight loss of about 4.5%, it's hard to see a major shift away from the oral drugs. The weight loss is better than with Belviq, comparable to that of Contrave, and not quite as good as Qsymia's, which has safety issues that prevent it from being the No. 1 drug.

Saxenda also has side effect warnings, including potential for thyroid cancer and pancreatitis, which should keep the drug from becoming the go-to drug for all obese patients.

Diabetics, on the other hand...While Saxenda is technically a new drug, the active ingredient is already approved and marketed as Victoza, a diabetes drug. The only difference is that Saxenda is dosed at a higher concentration than Victoza.

Many type 2 diabetics are overweight, so doctors might find that prescribing Saxenda can kill two birds with one stone. Saxenda is not actually approved to treat diabetes, but it should lower blood glucose levels just like the active ingredient does at the lower concentration. Losing weight should help control the diabetes as well.

Interestingly, a trial that only enrolled patients with type 2 diabetes resulted in a placebo-adjusted weight loss of 3.7%, compared to the aforementioned 4.5% weight loss in nondiabetics. That, though, could just indicative of it being harder for diabetics to lose weight. Orexigen saw a similar trend with 4.1% placebo-adjusted weight loss with Contrave in the general population, but just 2% placebo-adjusted weight loss in diabetics.

Depending on how Novo Nordisk prices the two drugs, patients switching from Victoza to Saxenda could be a win for the company. But most of the drug's potential should come from patients who aren't on Victoza, which is in a class of drugs that stimulate the GLP-1 receptor. Rather than hurting the current obesity drugs, Saxenda is most likely a threat to other GLP-1 drugs:AstraZeneca's Bydureon, GlaxoSmithKline's Tanzeum, and Eli Lilly's Trulicity.

It could even help the other obesity-drug makersTechnically, diabetics who might take Saxenda could take the current obesity drugs, but they aren't. VIVUS, Takeda (which markets Orexigen's drug), and Eisai (which markets Arena's drug) haven't even scratched the surface of the potential market for obesity drugs. It's a multibillion-dollar market -- the Centers for Disease Control and Prevention estimates a third of U.S. adults are obese -- but the companies combined are only producing sales in the hundreds of millions.

Having one more sales force expounding the benefits of losing weight should expand the market. Whatever diabetics these companies lose to Saxenda should be made up for by doctors' increasing comfort with prescribing obesity drugs, especially since the companies weren't capturing those diabetic patients anyway.

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