Methotrexate, Tafasitamab, Lenalidomide and Rituximab in Patients With PCNSL

This study is testing a 4-drug combination — methotrexate, tafasitamab, lenalidomide, and rituximab — for people with primary central nervous system lymphoma (PCNSL), a rare cancer that starts in the brain or spinal fluid. The combination targets cancer cells using both chemotherapy and antibody-based therapies. **You may be eligible if...** - You are 18 or older - You have newly diagnosed PCNSL confirmed by biopsy, spinal fluid analysis, or eye surgery sample - You are not a candidate for high-dose chemotherapy with stem cell transplant (due to age ≥70 or poor performance status) - Your kidney, liver, and bone marrow function are adequate **You may NOT be eligible if...** - You have already received treatment for PCNSL - Your organ function is significantly impaired - You are pregnant or breastfeeding - You are ineligible for other reasons determined by your doctor Talk to your doctor to see if this trial is right for you.