I have been on Gilenya for 3 years and am JC+. My specialist is a leading MS specific neurologist in Australia and says the risk of PML increases the longer you are on it.
The reading I have done on the 3 recorded cases of death related to PML whilst on Gilenya are a minute % of those successfully being treated on the drug. In addition, 2 of those cases had complications which suggest other factors were involved and therefore cannot be conclusively attributed to Gilenya as the sole factor.
I have not been on any other treatment prior to Gilenya, and cannot find any other treatment that offers the efficacy of Gilenya, the lack of lifestyle inhibiting side effects, nor the ease of use (sorry I sound like a rep haha).
The PML risk certainly concerns me a great deal, however my disease has not progressed whilst on gilenya and the chances of contracting PML seem so minute in comparison - I guess thats what you need to weigh up for your own situation? If you don't already, get a specialist who is up to date with the facts surrounding this issue so you can discuss.

I have been taking Gilenya for 3 years and have not had any problems. I tested positive for the JC virus but that's not uncommon. Just had brain and spine MRI's done, mostly just to check for lesions as it's been 5 years since I've had any MRI's done. Gilenya has worked very well for me. :)

I took Gilenya for 7 months, and it didn't help me at all. It was the first treatment I tried, and I had at least one relapse, if not more. When I went off Gilenya to prepare for taking Tysabri, I felt better than I had the previous 7 months with Gilenya. Everyone is different, though. As for the cases of PML, I wouldn't worry about them.. but, be aware of your symptoms, and if you have a radical change in them, let your doctor know right away.

My doc wouldn't put me in it when I asked two months ago. Said aren't sure why they are getting PML. Said they know why on Tecflideria. Gileyna seems to have less side effects. My brother has been taking Gileyna two years and loves it.

I've been taking gylenia for about a year and a half now and have had no problems with side effects or anything at all for that matter. I've only had one exasperation in that year and a half. Good luck