I'm probably going to try it in a few months once I hit the Tysabri 24 dose mark. PML seems a lot scarier to me then this. I can't tolerate copaxone or interferons. There have been cases of skin cancer on Gilenya -- not melanoma but basal cell carcinoma (which incidentally is not as dire as melanoma which can spread throughout your body). I think on this drug you will just have to watch your skin very closely and get regular full body scans from the dermatologist AND see an eye doctor for regular check ups. As far as damage to the liver can't the interferons and Tysabri also do a serious number on the liver? I've been on Tysabri for 2 years and my liver enzymes haven't changed one bit. They are the same numbers as when I started. I'm hoping I have a strong liver that can process this drug too. If I go on it, I will report back. Honestly I am more worried about the daily side effects which they list as headache, fatigue, flu, and diarrhea. I can't take any kind of flu like side effects--that just depresses me.