I have been on Gilenya for 3yrs. Several months ago I was diagnosed with breast cancer. My neurologist took me off Gilenya while I was going through treatments for cancer (lumpectomy and radiation). I'm now cancer free. My neurologist said I shouldn't go back on Gilenya because of my previous cancer diagnosis. He put me on another drug but the side effects bothered me so he took me off it. He now wants to put me back on Gilenya. I also tested positive for JC virus. I just read about the concern of Gilenya and the possibility of causing PML. Should I be concerned about going on Gilenya since I've had cancer and tested JC virus positive?
The incidence of PML in MS patients receiving Gilenya since its approval in 2010 is extremely low. There is no evidence that JC virus antibody studies predict the risk of PML on Gilenya or any therapy other than Tysabri. There is also no clinical evidence from post marketing studies that Gilenya interferes with the ability of your immune system to provide adequate surveillance against the recurrence of cancer, although this remains a theoretical concern with this treatment.
Risks are always relative and must be interpreted in the context of what makes you comfortable or uncomfortable. Although I know nothing about your MS, it is quite likely that your risk of MS worsening without effective treatment is much higher than your risk of developing PML or experiencing a recurrence of cancer as a result of treatment with Gilenya. You and your doctors have a better idea of the following information that is needed to help you with this decision:
1. What is the severity of your MS and your risk of becoming significantly disabled in the near term (i.e. next 5 to 10 years)? The higher the near term risk the greater the importance of initiating treatment with a highly effective treatment now. However, if you are already significantly disabled with problems walking and classified as either secondary or primary progressive MS, there is little evidence that Gilenya will be beneficial. In this situation the risk:benefit ratio may be reversed. A good way to think about this is to consider the last time you experienced your age, the last time you experienced a typical relapse and the manner in which MS has worsened over time; generally, if you are over 50, have not experienced a typical relapse in more than 2 years and have noticed slow worsening of you condition over a period in excess of 6 months, you have either secondary or primary progressive MS.
2. How effective was Gilenya during your prior three years of treatment with this drug? If it was only partially effective, perhaps another therapy is more appropriate at this time
3. What is your risk of cancer recurrence? If it is considered a very small risk based on cancer type, stage and treatment then there is less concern?
Hope this helps
Revere (Rip) Kinkel MD
Director of the Multiple Sclerosis Program
Professor of Clinical Neurosciences
University of California San Diego