[Evaluation of the effectiveness of treatment with rituximab associated to cyclophosphamide in patients with resistant idiopathic inflammatory myopathy].

Background And Objective: We report our experience with rituximab plus cyclophosphamide in the treatment of patients with resistant idiopathic inflammatory myopathies.

Patients And Method: Open-label uncontrolled prospective study on 17 patients.

Results: Evaluation was completed after 1, 6 and 12 months in 95'2, 85'7 y 52'4% of cycles, respectively. Total or partial remission was achieved after 1, 6 and 12 months in 65, 100 y 63'6% of evaluated cycles, respectively. Absolute depletion of B lymphocites from peripheral blood was found in the 18 cases with available data. There were 5 relapses; median of time to relapse: 11 months; treatment was repeated in 4. Four patients (6 cycles) had impaired pulmonary function; one (with a multifactorial etiology) did not improve but the other 3, with interstitial pneumonia associated or not with respiratory muscle weakness, did. Five patients with positive anti-Jo-1 antibodies (6 cycles) displayed similar results. The only adverse event observed was a case of meningitis caused by Corynebacterium, with good results.

Conclusion: Rituximab seems a valid alternative for the treatment of patients with resistant polymyositis or dermatomyosytis.