RESUMO
INTRODUCTION: Some experimental, Phase II clinical trials and the preliminary reports of the Cuban Phase III clinical trial indicate that alpha-IFN (IFN) may be useful in relapsing remitting (RR) multiple sclerosis (MS). The reports in Cuba showed that 70% of the MS patients have cognitive dysfunction. OBJECTIVE: To assess the efficacy of IFN-alpha2b recombinant in the cognitive dysfunction of RR MS. PATIENTS AND METHODS: 57 RR-MS clinical definite patients from the randomised, double blind, placebo controlled study of 225 patients with RR-MS and brain MRI confirmed. Patients were randomly assigned to receive intramuscular IFN-alpha2b (Heberon R) 10 million IU (high dose), 3 million IU (low dose) or placebo twice week for 2 years. Outcome results were blinding evaluated considering changes in the following tests: Luria, WAIS, Benton and PASAT-3. Adverse events and side effects were not evaluated to maintain physician blinding. RESULTS: The initial comparison of the groups did not show any differences among the placebo (n=20), low dose (n=18) and high dose (n=19) considering age (p=0.234), gender, ethnic group (p=0.012), years ill (p=0.787), EDSS (p=0.203) and rate of relapses (p=0.432). The Luria's Test showed an improved in the low dose group from 2.50 +/- 1.34 to 1.39 +/- 1.85 (p=0.029) and in the high dose group from 3.22 +/- 1.89 to 2.17 +/- 1.50 (p=0.006) vs placebo 2.85 +/- 1.66 to 2.90 +/- 1.97 (p=0.723). The results of the Benton's test demonstrated that the low dose group had an improved from 5.50 +/- 1.10 to 6.22 +/- 1.31 (p=0.047), in the high dose group from 4.87 +/- 1.85 to 5.78 +/- 1.35 (p=0.005) where as in the placebo group worse from 5.15 +/- 1.76 to 5.05 +/- 2.11 (p=0.893). The WAIS test showed the same results, the low dose group increased from 5.17 +/- 1.34 to 6.06 +/- 1.21 (p=0.022), the high dose group from 4.56 +/- 1.38 to 5.39 +/- 1.29 (p=0.007) and the placebo group worse from 5.25 +/- 1.25 to 5.05 +/- 1.57 (p=0.354). Finally, the PASAT-3 test increased in the IFNs groups: from 45.72 +/- 10.61 to 49.94 +/- 11.68 (p=0.015) in the low dose group, from 42.67 +/- 11.04 to 48.72 +/- 8.84 (p=0.03) in the high dose group, but in the placebo group worse from 44.55 +/- 10.86 to 41.95 +/- 13.74 (p=0.655). CONCLUSION: IFN-alpha improved the cognitive dysfunction in RR-MS patients. The higher dose is more beneficial.