Our review should provide some guidance to clinicians and patients. On the basis of high quality evidence, natalizumab and IFNß-1a (Rebif) are superior to all other treatments for preventing clinical relapses in RRMS in the short-term (24 months) compared to placebo. Moderate quality evidence supports a protective effect of natalizumab and IFNß-1a (Rebif) against disability progression in RRMS in the short-term compared to placebo. These treatments are associated with long-term serious adverse events and their benefit-risk balance might be unfavourable. IFNß-1b (Betaseron) and mitoxantrone probably decreased the odds of the participants with RRMS having relapses, compared with placebo (moderate quality of evidence). The benefit-risk balance with azathioprine is uncertain, however this agent might be effective in decreasing the odds of the participants with RRMS having relapses and disability progression over 24 to 36 months, compared with placebo. The lack of convincing efficacy data shows that IFNß-1a (Avonex), intravenous immunoglobulins, cyclophosphamide and long-term steroids have an unfavourable benefit-risk balance in RRMS. None of the included treatments are effective in decreasing disability progression in patients with progressive MS. It is important to consider that the clinical effects of all these treatments beyond two years are uncertain, a relevant point for a disease of 30 to 40 years duration. Direct head-to-head comparison(s) between natalizumab and IFNß-1a (Rebif) or between azathioprine and IFNß-1a (Rebif) should be top priority on the research agenda and follow-up of the trial cohorts should be mandatory.
Full results of the Evidence of Interferon Dose-Response-European North American Comparative Efficacy (EVIDENCE) study: a multicenter, randomized, assessor-blinded comparison of low-dose weekly versus high-dose, high-frequency interferon beta-1a for relapsing multiple sclerosis.
Interferon (IFN)-beta therapy represents an important advance in the management of relapsing multiple sclerosis (MS), but information about the relative benefits and risks of available preparations is limited.
                This report describes the full results of the Evidence of Interferon Dose-response-European North American Comparative Efficacy (EVIDENCE) study, combining analyses that were previously reported in separate publications for different phases of the study.
                The EVIDENCE study was a multicenter, randomized, assessor-blinded comparison of 2 IFN-beta dosing regimens. In the study, patients with relapsing MS were randomly assigned to SC IFN-beta1a 44 lag TIW (Rebif, Serono Inc., Geneva, Switzerland) or IM IFN-betala 30 mug QW (Avonex, Biogen Idec, Cambridge, Massachusetts) for 1 to 2 years. The primary clinical end point during the comparative phase was the proportion of patients who remained free from relapses; secondary and tertiary clinical end points included the annualized relapse rate and time to first relapse, re- spectively. All clinical and magnetic resonance imaging (MRI) evaluations were performed by blinded assessors. In the crossover phase of the study, patients who were originally randomized to low-dose QW treatment switched to the high-dose TIW treatment for an additional 8 months. Adverse events were determined by spontaneous reporting and monthly laboratory testing during the comparative phase.
                A total of 677 patients were enrolled in the study and evenly randomized to treatment; 605 patients completed the comparative phase and 439 completed the crossover phase. During the comparative phase, a significantly higher proportion of patients in the high-dose TIW treatment group remained free from relapses when compared with patients in the low-dose QW treatment group (adjusted odds ratio, 1.5; 95% CI, 1.1-2.0; P = 0.023). The high-dose TIW regimen was also associated with a significant reduction in the annualized relapse rate (-17%; P = 0.033) and a prolonged time to first relapse (hazard ratio, 0.70; P = 0.002). MRI measures of disease activity were significantly reduced in the high-dose TIW group compared with the low-dose QW treatment. During the crossover phase, a 50% reduction in mean relapse rates was observed in patients who converted from low-dose QW treatment to high-dose TIW treatment (P < 0.001), with significant concomitant reductions in MRI activity. Injection-site reactions were significantly more common with high-dose TIW treatment than with low-dose QW treatment (85% vs 33%; P < 0.001). Neutralizing antibody formation was more common with high-dose TIW treatment than with low-dose QW treatment (26% vs 3%; P < 0.001).
                The comparative phase of the EVIDENCE study found that treatment of MS with SC IFN-beta1a 44 microg TIW was associated with a significant reduction in clinical and imaging measures of disease activity over 1 to 2 years, when compared with IM IFN-betala 30 microg QW treatment. The crossover phase found that patients who changed from low-dose QW treatment to high-dose TIW treatment experienced enhanced benefits of treatment without a substantial increase in adverse events.