Magnetic resonance imaging as surrogate for clinical endpoints in multiple sclerosis: data on novel oral drugs.

Recent studies have provided evidence for using magnetic resonance imaging (MRI) active lesions as surrogate for relapses and disability progression in multiple sclerosis (MS). However, the validity of MRI metrics as surrogate endpoints in MS is controversial. Furthermore, the extrapolation of previous results to novel therapies is not warranted. We tested here the validity of MRI surrogacy in MS studies on recently published trials of oral drugs. The 92% of observed effects of oral drugs on clinical outcomes resulted close to those predicted by MRI active lesions. This further validates MRI surrogacy in MS, with important implications for future trials planning.