Fingolimod has been associated with potentially fatal infections, bradycardia, skin cancer and, recently, a case of haemorrhaging focal encephalitis, an inflammation of the brain with bleeding. Two subjects died: one due to brain herpes infection, second one due to zoster. It is unclear whether the drug was responsible for the events.
The most common side effects of fingolimod have been head colds, headache, and fatigue. But there have also been a few cases of skin cancer, which has also been reported in patients taking natalizumab (Tysabri), an approved MS drug.
Loren Rolak, MD, at the Marshfield Multiple Sclerosis Center, part of the Marshfield Clinic in Wisconsin, who was not involved in the fingolimod trials and has no relevant conflicts of interest, commented on the approval for the NMSS.
In discussing with his neurologist colleagues how the drug will be used in practice, Dr. Rolak says, "I've found a pretty wide range of opinion frankly." Some plan to approach use of fingolimod conservatively, since side effects in these trials, although fairly rare, were still serious, even fatal, which will give many pause. Others appear to be taking a more liberal view, he said, particularly since it has been shown to be not only as good as but better than standard therapy in TRANSFORMS.