Successful treatment of Epstein–Barr virus–associated primary central nervous system lymphoma due to post‐transplantation lymphoproliferative disorder, with ibrutinib and third‐party Epstein–Barr virus–specific T cells

Primary central nervous system lymphoma (PCNSL) occurring following organ transplantation (post‐transplantation lymphoproliferative disorder [PTLD]) is a highly aggressive non‐Hodgkin lymphoma. It is typically treated with high‐dose methotrexate‐based regimens. Outcomes are dismal and clinical trials are lacking. It is almost always Epstein–Barr virus (EBV) associated. Two patients (CA1‐2) presented with EBV‐associated PCNSL after renal transplant. CA1 was on hemodialysis and had prior disseminated cryptococcus and pseudomonas bronchiectasis, precluding treatment with methotrexate. CA2 was refractory to methotrexate. Both were treated off‐label with the first‐generation Bruton's tyrosine kinase inhibitor ibrutinib for 12 months. Cerebrospinal fluid penetration at therapeutic levels was confirmed in CA1 despite hemodialysis. Both patients entered remission by 2 months. Sequencing confirmed absence of genetic aberrations in human leukocyte antigen (HLA) class I/II and antigen‐presentation/processing genes, indicating retention of the ability to present EBV‐antigens. Between Weeks 10 and 13, they received third‐party EBV‐specific T cells for consolidation with no adverse effects. They remain in remission ≥34 months since therapy began. The strength of these findings led to an ongoing phase I study (ACTRN12618001541291). Treatment with Bruton’s tyrosine kinase inhibitor, ibrutinib along with consolidation with adoptive transfer of third‐party Epstein–Barr virus–specific cytotoxic T cells achieves sustained remission for two patients with primary central nervous system lymphoma after transplantation.