Glofitamab Plus Gemcitabine and Oxaliplatin (GemOx) in Relapsed or Refractory Primary and Secondary Central Nervous System Lymphoma

This study is being done to find out whether the combination of glofitamab, gemcitabine and oxaliplatin (GemOx) works and is safe in people whose lymphoma has come back or has not responded to previous treatment and has spread to the central nervous system (the brain, spinal cord, cerebrospinal fluid and/or eye). Central nervous system lymphoma is difficult to treat, and there is no agreed standard treatment once it returns. Glofitamab is a bispecific antibody that helps the body\'s own immune T cells attach to and destroy lymphoma B cells.All participants will receive the study treatment every 3 weeks for up to 6 treatment cycles, followed by maintenance treatment in participants whose lymphoma shrinks or disappears. The main goal is to measure how many participants respond to the treatment; the study will also measure how long responses last and what side effects occur.