Biosimilar Rituximab Appears to Be Safe in Mixed Cryoglobulinemic Vasculitis

Mixed cryoglobulinemic vasculitis (MCV)—a rare disorder that is characterized by the presence of abnormal proteins in the blood that become insoluble at low temperatures and restrict blood flow—may be successfully managed with the use of rituximab as a generally well tolerated, glucocorticoid-sparing therapy.

Biosimilar rituximab, which is available in the European Union, has the potential to reduce the cost associated with rituximab therapy for this rare disease, but few data are available about biosimilar rituximab’s safety and effectiveness in patients with MCV.

An Italian study recently presented at the European League Against Rheumatism’s 2019 congress analyzed the safety of the biosimilar in patients with MCV. In the multicenter, open-label study, all patients with MCV who were treated with the biosimilar, either with the biosimilar as first-line treatment or after switching from the reference rituximab product, were included.

In total, 19 patients were treated in a 6-month period in 2018. Nine of them were treated with the biosimilar only, while 10 switched from the reference.

In the month following the patients’ final infusions, 5 adverse events (AEs) were observed: 2 vasculitis flares, and 1 case each of urticaria, atrial fibrillation, and septicemia. Three of the 5 AEs occurred in patients receiving high doses of rituximab.

There were no differences observed in AEs between the treatment-naïve patients and those switched from the reference.

Despite the low number of patients included in the study, write the authors, switching to the biosimilar appeared to be safe, and AEs were in line with the known safety profile of rituximab in MCV.

Reference

Vacchi C, Visentini M, Cicco MD, et al. Safety of rituximab biosimilar for the treatment of cryoglobulinemic vasculitis. Presented at: The European League Against Rheumatism European Congress of Rheumatology 2019; June 12-15, 2019; Madrid, Spain. Abstract AB0624.