Complex sentence: The most common side effects of fingolimod have been head colds, headache, and fatigue, but a few cases of skin cancer have been reported, which has also been reported in patients taking natalizumab (Tysabri), an approved MS drug.
Split into simpler sentences: The most common side effects of fingolimod have been head colds, headache, and fatigue. A few cases of skin cancer have been reported, which has also been reported in patients taking natalizumab (Tysabri), an approved MS drug.