Does the Return of Tysabri Signal a New Direction?

J0321197 On February 28th, 2005, Biogen Idec and Elan announced the market suspension of Tysabri, a treatment for multiple sclerosis.  The voluntary action was taken, per the Dear Healthcare Professional letter issued by the companies, out of reports that two patients treated with Tysabri and Avonex developed progressive multifocal leukoencephalopathy (PML).  PML is a particularly rare, but insidious disease that I can best describe, having seen it twice kill friends of mine, as a rapid Lou Gehrig’s disease.  The patient loses motor control, but not over a period of years – more like a period of weeks or months. 

On March 8, a meeting of the Peripheral and Nervous Systems Drugs Advisory Committee (PNSDAC) was held to evaluate whether the drug should return to the market.  They voted unanimously to recommend the treatment’s return.

This has led some to question whether or not this signals a new direction on the part of the FDA – is there a belief that the agency is taking drugs off the market too quickly at a sign of trouble. 

I don’t claim to have inside-FDA knowledge of their thinking, or whether the agency actually has thinking along these lines.  But I have watched the agency for years and I have watched the evolution of the art/science of risk management develop. 

This is not the first troubled drug to return to market.  As I mentioned in an earlier posting, in 1997, I was a speaker at an NIH two-day meeting on risk management considerations involved in bringing thalidomide back to the market.  In 2002, I attended the advisory committee meetings that resulted in the return of Lotronex, a treatment for Irritable Bowel Syndrome (IBS) to the market (I had also attended the Lotronex advisory committee meeting where it was approved). 

While I am a lawyer and not a doctor, sitting through the Lotronex risk management meeting, the evidence presented made it seem likely that adverse events seemed linked to inappropriate prescriptions of the drug, and that closer management could substantially reduce risk.  There was a clear patient need for a treatment among the sector of patients who suffered from IBS who were appropriate for the drug. 

Thalidomide also offered promise where there was great need.  I think the vote to return Tysabri to the market is less about a change of direction than it is testament to the fact that some treatments that provide solid benefit, also may have risks that can be better managed.  And when the risk is discovered, it is best to suspend the market until the matter can be better analyzed and, if possible resolved. 

I wouldn’t read more into it than that.   

If you are interested in learning more about the return of Tysabri, go the the National MS Society Web site, which has a very good Q&A on the topic. 

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