Efficacy of low-dose rituximab for the treatment of mixed cryoglobulinemia vasculitis: Phase II clinical trial and systematic review

• Rituximab at the low dosage of 250 mg/m2 x 2 is efficacious refractory HCV-associated mixed cryoglobulinemic vasculitis
• Low-dose rituximab is as effective as the higher dosage of 375 mg/m2 x 4 for treating mixed cryoglobulinemia
• The low-dose regimen may improve the cost/benefit profile of rituximab therapy for mixed cryoglobulinemia.

ObjectiveTo evaluate whether rituximab at a low dose of 250 mg/m2 × 2 may be as effective as at higher dosages, most commonly 375 mg/m2 × 4, used in previous studies on the treatment of patients with refractory mixed cryoglobulinemia (MC) vasculitis associated with hepatitis C virus (HCV) infection.MethodsWe conducted a phase 2, single-arm two-stage trial (EUDRACT n. 2008-000086-38) of low-dose rituximab in 52 patients with HCV-associated MC who were ineligible/intolerant or non-responder to antiviral therapy. The primary outcomes were response of vasculitis evaluated by the Birmingham Vasculitis Activity Score (BVAS) at months 3, 6 and 12, rate of relapses and time to relapse, and rate of adverse events. Our data were compared with those reported in 19 published studies selected among 291 reviewed in a literature search.ResultsThe cumulative response rate (complete and partial) at month 3 was 81% in our patients, and 86% in 208 patients from studies using high-dose rituximab. The relapse rate and median time to relapse were, respectively, 41% and 6 months in our study, and 32% and 7 months in high-dose studies. Treatment-related adverse events were 11.5% in our study and 19.9% in high-dose studies. None of these differences was statistically significant.ConclusionRituximab at a low dosage of 250 mg/m2 × 2 is as effective as at higher dosages for treating MC vasculitis. This low-dose regimen may improve the cost/benefit profile of rituximab therapy for MC.