Impact of maintenance rituximab on duration of response in primary central nervous system lymphoma

The role of maintenance immunotherapy with anti-CD20 monoclonal antibody rituximab in primary central nervous system lymphoma (PCNSL) is unclear. We retrospectively reviewed the medical records of all immunocompetent adults with newly diagnosed PCNSL treated at our institution between1996 and 2017. We identified 66 patients who attained complete response (CR) after completion of first-line regimen; 20 received maintenance therapy (maintenance therapy group) and 46 were observed with serial MRI scans without maintenance therapy (no-maintenance therapy group). Compared to the surveillance group, there was a significant increase in duration of survival (HR 0.27, 95% CI 0.08–0.98, P = 0.046) in the maintenance therapy group while the reduction in the risk of progression was not significant (HR: 0.61, 95% CI 0.26–1.43, P = 0.259). We are evaluating the effectiveness of maintenance immunotherapy in PCNSL in a prospective multicenter randomized clinical trial.