Rituximab, a B-cell–depleting agent, has been found safe and effective in clinical trials of patients with multiple sclerosis and patients with rheumatoid arthritis, among others. However, progressive multifocal leukoencephalopathy (PML) and malignancies have been reported in patients with lymphoma, rheumatoid arthritis, and lupus who also received multiple immunosuppressive therapies, say researchers from Wayne State University in Michigan and University of Chicago in Illinois. In studies with ocrelizumab, which also depletes B-cells, adverse effects (AEs) have included infections, such as, herpes virus-associated infection, and neoplasms.
Although most research has found rituximab and ocrelizumab safe and effective, there is a “paucity of literature” on the safety of continuous B-cell depletion over a long period, the researchers say. They conducted a retrospective study involving 29 patients with immune-mediated neurologic disorders who received continuous cycles of rituximab infusions every 6 to 9 months for up to 7 years. Although small, the study was longer than the trials with ocrelizumab in multiple sclerosis . The mean duration of treatment was 51 months; with a mean of 9 treatment cycles.
The researchers found a low incidence of adverse events and prolonged rituximab-induced B-cell depletion did not lead to any life-threatening AEs, including malignancy. Overall, 32 AEs were reported. Four were serious; 3 were noted after 9 cycles (48 months), and 1 after 11 cycles (60 months). There were no cases of PML or malignancies. Repeated rituximab infusions were well tolerated The rate of AEs remained low over the 7-year observation period.
Memon AB, Javed A, Caon C, et al. PLoS ONE. 2018;13(1):e0190425.