Azathioprine versus Beta Interferons for Relapsing- Remitting Multiple Sclerosis: A Multicentre Randomized

For almost three decades in many countries azathioprine has been used to treat relapsing-remitting multiple sclerosis. However its efficacy was usually considered marginal and following approval of b interferons for this indication it was no longer recommended as first line treatment, even if presently no conclusive direct b interferon-azathioprine comparison exists. To compare azathioprine efficacy versus the currently available b interferons in relapsing-remitting multiple sclerosis, a multicenter, randomized, controlled, single-blinded, non-inferiority trial was conducted in 30 Italian multiple sclerosis centers. Eligible patients (relapsing-remitting course; $2 relapses in the last 2 years) were randomly assigned to azathioprine or b interferons. The primary outcome was annualized relapse rate ratio (RR) over 2 years. Key secondary outcome was number of new brain MRI lesions. Patients (n = 150) were randomized in 2 groups (77 azathioprine, 73 b interferons). At 2 years, clinical evaluation was completed in 127 patients (62 azathioprine, 65 b interferons). Annualized relapse rate was 0.26 (95 % Confidence Interval, CI, 0.19–0.37) in the azathioprine and 0.39 (95 % CI 0.30–0.51) in the interferon group. Non-inferiority analysis showed that azathioprine was at least as effective as b interferons (relaps