Efficacy and safety of long-term treatment with low-dose rituximab for relapsing mixed cryoglobulinemia vasculitis

This study aims to evaluate the efficacy and safety of repeated treatments with low-dose rituximab for relapsing mixed cryoglobulinemia vasculitis. Thirty-seven patients with mixed cryoglobulinemia vasculitis refractory to standard of care treatment, 34 of which were HCV-positive, were treated with rituximab at the reduced dosage of 250 mg/m² given twice 1 week apart per cycle. Thirty patients (81%) achieved a clinical response; 5 of them remain in remission, 3 were lost to follow-up or died, and 22 relapsed after a mean of 15.7 months. Eleven relapsers were retreated with one (6 patients), 2 (3 patients), or 3 (2 patients) additional rituximab cycles given at each relapse. Clinical and laboratory efficacy and side effects of long-term treatment were evaluated. Clinical response to retreatment was 91% (10/11) at the first relapse, 80% (4/5) at the second relapse, and 100% (2/2) at the third relapse. The mean (±SD) time to relapse was 17.1 ± 14.1 months in 30 patients who were treated with only one cycle (from first cycle to the first relapse) and 45.7 ± 30.6 months (from first cycle to the last observed relapse) in 11 patients treated with 2 or more cycles (p = 0.0037). Severe adverse reactions occurred in 3 patients, in 2 of whom at the first cycle. Our results suggest that repeated treatment of relapsing mixed cryoglobulinemia with a low-dose rituximab regimen is efficacious, safe, and cost-effective for the long-term management of this disorder.