I've been on Tysabri approaching 2 years. First JCV test 18 months ago came out positive. Since improvement has been made in testing results, second test came out as .43 six months ago. Just received result of .32 from test one month ago. Should I be seriously considering an alternative , such as Tecfidera or Gilenya? Two year PML window closing soon.
You have a very low index level but a positive JCV antibody result. Very few individuals have developed PML with an index value this low but there is still some uncertainty regarding the long term risk of treatment beyond 4-5 years in people with low index values. What you do about treatment depends on three things:
1. Your tolerance for a very low risk outcome like PML
2. Your disease severity and response to prior therapies
3. Your response to Tysabri for the past 2 years
If you feel Tysabri has been good for you and your disease warrants this treatment, it is reasonable to continue on this treatment. There is increasing evidence that increasing the interval between treatments to 8 weeks instead of 4 weeks decreases the risk of PML. This is particularly true of people with low body mass index usually under 60-70 kg in weight.
I would suggest discussing your options further with your MS specialist.
Revere Kinkel MD
Director of the UCSD Multiple Sclerosis Program