While I'm rarely one to stand up for the drug companies, and routinely pillory Big Pharma on my blog, Tysabri has dramatically impacted many patient's lives for the better, so much so that those who benefit from it are loathe to come off of it even if they eventually test JC positive. Considering the destruction that can be wrought by aggressive MS, and the turnaround that many patients experience after taking Tysabri, the risk of PML seems, to them, to be worth it. Furthermore, as more is learned, doctors are becoming more sophisticated in their use of the drug. Many are not prescribing it for patients who are JC positive, and for those who are JC negative the risk of PML is quite negligible.
Again, I don't trust big Pharma as far as I can spit, and I think some of Biogen's business practices are despicable, if not downright unlawful, but Tysabri has been responsible for the dramatic improvement in quality of life for many patients taking it. Remember, it was MS patients who lobbied the FDA to reinstate the drug, although biogens malfeasance and obfuscation surrounding the true risk of PML was and is deplorable.
As with all things MS, it's a complicated issue…
Yes, many MS patients have benefitted from Tysabri but over the years but so have patients who have used Betaseron, Avonex, Copaxone and Rebif. The efficacy rate of the CRAB drugs has been quite debatable though and the efficacy of Tysabri doesn't appear to be as high as Biogen initially told us. And the long term use of this drug is one big question mark at the moment.
What I really object to is how Biogen introduced Tysabri and the marketing/sales gimmicks they have used despite not being aware of the safety issues. I guess time will tell on how well the drug works and how many people become very sick while using it.