I think that you have to weigh the pros and cons with tysabri just as you do with any drug therapy. In my case I am allergic to interferons and had too many bad reactions to copaxone. (5 serious IPIRs in 4 1/2 months) So I decided to go on tysabri after alot of deliberation. I did not make this decision blindly. It is true that no one know the long term side effects of this drug. That is true of all new drug therapies. So I could wait a few more years, take nothing, and have my MS progress. Or I could try to get into a study where I may be taking a placebo and the drug being studied may also have potential problems associated with it. I know that tysabri is not the "silver bullet" but I
am willing to take the risk. Quality of life is more important to me. Oh, I have scheduled an appointment with a dermatologist for a full body mole check and I am planning to ask my neuro about bloodwork at my 4th tysabri appointment on Wednesday. I also am experiencing less fatigue and I am using my cane less.