Vivus Beating Arena, Orexigen In Obesity Graveyard Race

(MoneyWatch)  The race to produce a blockbuster anti-obesity pill -- a contest that no company has yet won -- got interesting this week with the news, via AP, that Arena Pharmaceuticals' data showed that its contender, lorcaserin, showed only 3.6 percent more effectiveness than a placebo. The FDA wants to see 5 percent more effectiveness -- thus Arena's stock tumbled.

The AP updates on the progress of two other companies trying the same thing:

Potential competitor La Jolla, Calif.-based Orexigen Therapeutics Inc. experienced a similar plunge in its stock price in January after the developing drug Contrave fell shy of the same FDA benchmark, despite meeting other study criteria. The difference in a late-stage study of the drug amounted to 4.2 percentage points.

In December, though, Mountain View, Calif.-based Vivus Inc. reported a difference of 7.5 percentage points for its developing obesity drug Qnexa in a late-stage study.

So, Vivus would appear to be winning. Or is it? Here's what's in Qnexa:

... the active ingredients from two previously approved products with demonstrated weight loss properties: phentermine and topiramate.

You should know that phentermine is a type of amphetamine; and topiramate is an anti-seizure, antimigraine, antidepressant drug better known as Topamax.

Doesn't sound quite so attractive now, does it? Even if it demonstrates efficacy, the warnings on the label are going to be scary looking. ("Doctor, will you prescribe me a speed-based anti-seizure medicine so I can lose some weight?")

As usual, Derek Lowe's take on why obesity drugs are such big money losers is far more elegant than ours:

... human feeding behavior is protected by multiple, overlapping redundant pathways. We are the descendants of a long line of creatures that have made eating and reproducing their absolute priorities in life, and neither of those behaviors is going to be altered lightly. The animals that can be convinced to voluntarily eat so little that they actually lose weight, just through modifying a single biochemical pathway, are all dead. Our ancestors were the other guys.

• Obesity: A Graveyard of Failed Pharma Products
• FDA Moves Against Unapproved Obesity Drugs
• Pfizer in November 2008 scrapped its anti-fat drug, the unnamed "CP-945,598," for "regulatory" reasons.
• Sanofi-Aventis in November 2008 announced that it was ending its trials on Acomplia/Zimulti, an obesity pill that was approved and then yanked in Europe.
• Merck in November 2008 pulled its fat pill, taranabant, from its pipeline.
• GlaxoSmithKline has had dissappointing sales from Alli so far.
• Roche had negligible sales from Xenical, the Rx version of Alli.
• Solvay in November 2008 also abandoned its attempt to bring an anti-fat pill to market.
• Abbott Labs sold Meridia, but it failed to take off due to cardiovascular concerns.
• Wyeth abandoned fen-phen and Redux after they produced lawsuits.