High-Dose Methotrexate Containing Induction Chemotherapy Followed By Nivolumab Consolidation in Older (≥ 65) Patients with Previously Untreated Primary CNS Lymphoma

Introduction: High-dose methotrexate (HD-MTX)-containing chemotherapy followed by either autologous stem cell transplant (ASCT) or whole-brain irradiation (WBI) is widely considered the standard for primary CNS lymphoma (PCNSL) treatment. However, many older frail patients with PCNSL are unable to undergo ASCT or WBI due to increased risk of treatment-related toxicity, such as infections and neurotoxicity. Without consolidation, survival outcomes are significantly worse, with a 3-year progression free survival (PFS) rate of ~ 30%. Therefore, novel therapeutic approaches are urgently needed for older PCNSL patients. Recently, nivolumab, an anti-PD1 antibody, showed promising clinical activities in relapsed/refractory PCNSL, and we hypothesized that addition of nivolumab in the frontline setting would be safe and improve survival outcomes of older PCNSL patients who are deemed poor candidates for ASCT or WBI.