Epcoritamab for the Treatment of Relapsed or Refractory Post Transplant Lymphoproliferative Disorders

This study is testing epcoritamab, a new type of cancer immunotherapy drug, for people who have developed a serious condition called post-transplant lymphoproliferative disorder (PTLD) — a type of lymphoma that can occur after an organ transplant. PTLD arises when the immune system, weakened by anti-rejection drugs, can't control certain viral infections that trigger abnormal cell growth. **You may be eligible if...** - You are 18 or older and had a solid organ transplant - You have been diagnosed with B-cell PTLD that expresses a protein called CD20 - Previous treatments (reduction of immunosuppression, rituximab, or chemotherapy) have not worked - Your functional status score is acceptable (Karnofsky ≥ 50% or ECOG ≤ 2) **You may NOT be eligible if...** - You have active uncontrolled infection - You have certain other serious medical conditions that make this treatment too risky - You have already received certain other recent immunotherapy treatments Talk to your doctor to see if this trial is right for you.