Originally Posted by dopadoc

Sales of ropinirole have run at a respectable clip approaching 400 million USD per year and GSK is about to introduce a new RLS drug called Horizant. Why get FDA approval for a drug that treats a condition that your own cheaper drug, ropinirole, can deal with just as well? It is alleged by another author that an overriding agenda rules the situation: off-label sales.

OFF-LABEL SALES

The term “off-label” refers to the legal sale of a drug for a use for which it is not FDA-approved. So long as a doctor approves, you can be taking levodopa for a sore throat. Firms are not allowed to advertise for these non-approved applications of their drug and so they have separate employees assigned called “Physician liasons” who are kept separate from the salespeople, and who are allowed to distribute published literature on off-label uses. They are also allowed to send physicians who might be famous for off-label uses around on an “educational speakers’circuit” so long as the docs don’t feel pressured to plug the drug being advertised.

Sadly many of the docs on the speaker circuit are well-compensated but often don’t even know they’ve been assigned this role. They’re led to believe that it’s more of an educational entertainment thing to get the drug sales rep’s face to face with other physicians to give their pitch. They often don’t realize that their discussion of off-label use is really indirect advertising that opens up a new market for the drug while saving them the 150M dollars or more required to meet all the hoops and hurdles that the FDA requires for formal approval, the most important one being safety.

It is alleged that there are big hopes for Horizant’s off-label use as an anti-Parkinson’s drug. If that’s true where’s the proof? Gabapentin, the active component is not a dopamine agonist. It works on the GABA receptors in the basal ganglia. Another form of gabapentin called Neurontin was originally approved for anti-seizure therapy and then was sold through off-label channels to treat everything from bipolar disorder to chronic pain–but never Parkinson’s. Neurontin’s maker, Pfizer withstood a great deal of criticism and was even sued for allegedly promoting the drug for off-label uses it knew it to be ineffective.

Well thankfully it turns out that gabapentin has been cited in numerous studies as far back as the late 90′s to be effective in treating the motor symptoms, motor fluctuations and tremor in PD. Formal FDA studies are very expensive. I imagine that dealing with complicated PD patients, most of whom already take one or several drugs, would make the task of FDA approval for its use in Parkinson’s a great deal more expensive and difficult. Proving safety of a drug that tends to be mildly sedating in a patient group at risk for traumatic falls might be near to impossible. The alleged off-label route would be much easier as I am certain FDA approval for treatment of RLS (a sedating drug in otherwise healthy patients going off to sleep and measuring leg motion) would prove to be much less complicated.

Thus, if what is being alleged is true, a new RLS drug on the horizon, aptly named Horizant will soon be available for off-label use in Parkinson’s: safety testing not-included.