Tysabri's response rate is ~61%. The odds of something horrible happening in the first 3 months during which you establish efficacy are next to none. The FDA requires a check up at 3 mo and 6 mo. For me it didn't work. It was unclear at the time because I continued on rectal steroids. At 6 months the anxiety of the potential ill effects combined with the concern that it was the steroids, NOT Tysabri, helping... I quit. Been better on the steroids alone (since I can take them daily, rectal budesonide).
If you really feel like you want to try Tysabri and the other treatments have not worked, it's worth a try. Once you figure out if it works you could determine whether it's worth the risk. If you don't feel like you can emotionally handle the risk, that's ok too. It's a very personal decision.
--40 year old female, dx as UC in '04 (1st symptoms in '03), switched to Crohn's in '05, 1 fistula, crohn's colitis, limited to large intestine --rejected (reaction/didn't work): Asacol, AZA, 6-MP, MTX, Remicade, Humira, prednisone
--Prochymal in Phase III study (can't wait til it's approved!)
--started Tysabri 3/21/08 => STOPPED 10/3/08 - now 2 months into it & it was the right decision
--currently taking budesonide suppositories, 3mg at night. Doing well with this so far.
--single mom to 11-yr-old girl