HelpI have had about 55 treatments on Tysabri. Although I am doing very well I don't know when enough is enough. I had been on Beta Seron before the Tysabri, the side effects were terrible. My only other choice would probably be Copaxone but I know it is not as strong (so why shouldn't I have the best). The new pills are out of the question because of the cancer causing agents I read about. I have taken the test for PML and the results were that the gene is detected. Should I stay on the Tysabri or do something else?