A Cochrane review «La Mantia L, Vacchi L, Di Pietrantonj C ym. Interf...»1 included 5 RCTs with 3 122 patients with secondary progressive multiple sclerosis (MS). In all included studies secondary progression was defined as a period of deterioration sustained for at least 6 months, after a period of relapsing-remitting phase. Patients were heterogeneous regarding the baseline characteristics of the disease, especially the rate of patients affected by superimposed relapse ranged from 44 % to 72 %. Treatment duration was 2 years in one study and 3 years in 4 studies. Interferon (IFN) beta 1a and 1b did not decrease the risk of progression sustained at 6 months (RR 0.98, 95 % CI 0.82–1.16; 3 trials, n = 2 026) after 3 years of treatment. However, a significant decrease in the risk of progression sustained at 3 months, reflecting relapse-related disability (RR 0.88, 95 % CI 0.80–0.97; 2 trials, n = 1 336), and of the risk of developing new relapses at 3 years (RR 0.91, 95 % CI 0.84–0.97; 4 trials, n = 2 639) were found. However, these differences cannot be considered clinically relevant. The risk of developing new active brain lesions decreased over time but these data were obtained from single studies on MRI performed in subgroups of patients. In spite of no effect on progression, the radiological data supported an effect on MRI parameters. The safety profile reflects what is commonly reported in MS IFN-treated patients.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in study populations).