Sequential Treatment With RO-MTX After Pomalidomide, Orelabrutinib, Rituximab (POR) in Newly-diagnosed PCNSL

This study is testing a sequential treatment approach for people newly diagnosed with primary CNS lymphoma — a rare lymphoma that grows in the brain or spinal cord. After initial treatment with pomalidomide and orelabrutinib, patients receive a consolidation regimen using methotrexate (RO-MTX) to build on the response achieved. **You may be eligible if...** - You are between 18 and 70 years old - You have been newly diagnosed with primary CNS lymphoma confirmed as B-cell type - Your bone marrow blood production is within acceptable range - Your lymphoma is limited to the central nervous system and has not spread from another site in the body **You may NOT be eligible if...** - Your lymphoma is T-cell type (not B-cell) - Your lymphoma originated outside the brain and spread to it - You have an active serious infection - You have had a recent heart attack or unstable heart disease - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.