GlaxoSmithKline Bets Solzira Can Win Where Requip Failed

(MoneyWatch)  GlaxoSmithKline's announcement yesterday that it is submitting a new drug application for Solzira to the FDA for the treatment of Restless Legs Syndrome raises a question: What was wrong with its old treatment for RLS, Requip, launched only in 2005?

The short answer is that it was destroyed, in part by an association with gambling addiction, but mostly when it went generic. GSK reported Requip only generated ?£58 million in sales worldwide last quarter.

That raises a further question as to whether it is wise to launch Solzira against cheap generics. As I have mentioned a couple of times recently, there's a well-established law of competition in the drug business: cheap generics win. But with this launch, GSK is joining Cephalon and Shire as companies that have decided that this law somehow doesn't apply to them.

On its face, there is little evidence to suggest that GSK is right in coming to this conclusion. Requip's life at GSK was short and unhappy. It generated $986 million in sales from 2005 to 2007, according to this excellent MSNBC report. Nielsen Monitor-Plus tells me that over the same period, GSK spent $248 million advertising Requip in TV and print ads. Put another way, 25 percent of Requip's revenues were immediately burned by its adspend -- that's an astonishingly inefficient marketing effort, and a stand-out example of why people believe that drug advertising makes medicine more expensive.

On the other hand, GSK may be eyeing a very different set of facts. Requip was dogged by rumors that it causes a pathological gambling addiction among some of its users. This is because it is a dopamine agonist, like its sister drug Mirapex, which produces a "high" that makes users think they are geniuses at roulette. In fact Requip's label has warnings about gambling on it.

The interesting thing, therefore, about the Solzira application is that it is not a dopamine agonist. It's a gabapentin, and gabapentin isn't associated with the urge to rent a limo and stay up all night in Atlantic City.

So maybe GSK thinks this new gabapentin, with its lower side effect profile, can dominate lesser generics. Possibly. Until, of course, doctors wake up to the fact that there are already plenty of generic gabapentins on the market, such as Neurontin.

Which brings me back to my first point about the laws of competition in the drug business ...