Why Glaxo Will Be Furious At FDA's New Side Effect Warning for Its Diet Drug Alli

Last Updated May 26, 2010 4:53 PM EDT

GlaxoSmithKline (GSK)'s reaction to the FDA's new liver damage warning on its diet drug Alli is considerably calmer than the one it had when the feds first started probing the drug's safety record. Nonetheless, you can bet that GSK's vp of behavioural science, Karen Scollick, has steam coming out of her ears at the FDA's requirement that Alli now carry a warning that says:
Stop use and ask a doctor if you develop itching, yellow eyes or skin, dark urine or loss of appetite. There have been rare reports of liver injury in people taking orlistat [Alli].
Scollick's anger will be justified. When the FDA started its inquiry, it believed 32 cases of liver damage were associated with the drug. With the jury back, only 13 cases worldwide have been found: So Alli is arguably safer than the FDA thought it was going in.

GSK insists that as Alli isn't actually absorbed by the body -- it merely blocks fat in the gut which is then famously excreted by the patient -- it cannot possibly cause liver damage. The company even hinted that fat people's own eating habits were more likely to cause liver problems than Alli. Indeed, no causal link was found -- vindicating the company's position and likely angering its staff over having to carry the warning anyway.

Although two people died and three required liver transplants after using the drug, the product has been consumed by 40 million patients worldwide, so it's reasonable to ask whether that rate of liver failure isn't just the normal background level -- something that the FDA's Q&A doesn't address. Also, only one of the cases was associated with Alli, the rest were linked to Roche's stronger prescription version, Xenical. From that angle, you can see why GSK might feel it is being unfairly singled out.

The warning won't help Alli gain its footing in the marketplace. Even though sales doubled last year, they're still only £63 million worldwide -- a piffling amount for a diet drug that basically works and is basically safe.