Time for Big Pharma to Place Some Bets on Obesity?

Last Updated Jul 21, 2009 12:20 AM EDT

I wonder if there are any memos circulating at big pharma today that look like this:
CONFIDENTIAL MEMO
TO: High-Powered Big Pharma Business Development Exec
FROM: Higher-Powered Big Pharma CEO
RE: Time to sh*t or get off the pot on obesity
Seriously, unpartnered late-stage biotech assets are hard to come by these days. So it's surprising that all three of the leading experimental drugs for obesity -- Vivus' Qnexa (phentermine/topiramate), Arena Pharmaceuticals' lorcaserin and Orexigen Therapeutics' Contrave (bupropion SR/naltrexone SR) -- remain available on the partnering table.

All three of these drugs have achieved at least some degree of success in Phase III. Qnexa's first Phase III hit both of the FDA's guidelines, showing placebo-adjusted weight loss of 7.5 percent (more than the 5 percent minimum), with 66 percent of patients losing at least 5 percent of their weight (more than double the 15 percent for placebo). Arena's first Phase III with lorcaserin showed just 3.6 percent placebo-adjusted weight loss, but 47.5 percent of patients lost at least 5 percent, more than double the 20.3 percent of placebo patients.

Orexigen's first Phase III trial appeared to strike out on both counts, thanks to a wonky trial design that created a high placebo hurdle. But results from three other Phase III trials, released today, confirmed what folks familiar with the data already knew: the drug is capable of meeting the FDA's goals. Placebo-adjusted weight loss was between 4.8 percent and 5.2 percent in the studies, and all dosing groups in all studies more than doubled placebo for patients losing at least 5 percent of their weight.

Analysts have predicted that all three of these obesity drugs will eventually gain FDA approval. Yet no big pharma partners have signed on the dotted line. In fact, most analysts expect pharma to remain on the sidelines until all the Phase III data for all three drugs become available, and possibly even longer.

What are they waiting for?

The obesity market is certainly big enough to support multiple comers. Or at least it could be, if the comers offered meaningful efficacy and tolerable side effects. So far, that's proven easier said than done. The field has had more than its share of disappointments, from the safety nightmare of Fen-Phen (dexfenfluramine-phentermine) to lackluster sales of approved options like Roche's Xenical (orlistat) and Abbott's Meridia (sibutramine HCl monohydrate capsules C-IV) to discontinued big pharma efforts (Pfizer, Merck, Sanofi-Aventis).

But despite all the setbacks, it's hard to believe big pharma would pass up a new chance to grab a slice of the obesity pie. Sure it's risky, but so is everything in biotech.

So maybe the pharmas are all just trying to determine which of the three biotech contenders has the most potential. If so, how long are they going to wait? Orexigen's Phase III program is done and the other two will wrap this quarter. Are any of the pharmas worried that if they don't make a move soon, someone else will?

Obesity photo by Fickr user colros, CC2.0

  • Trista Morrison

    Trista Morrison is a staff writer at BioWorld Today, a daily newspaper that