Ibrutinib Monotherapy as Bridge-to-Transplant for Relapsed/Refractory Primary Oculo-Cerebral Lymphoma

Introduction: Primary central nervous system lymphoma is an uncommon form of extranodal non-Hodgkin's lymphoma, with increasing incidence, a relatively aggressive course and a poor 5-year survival. Because of its localization, the therapeutic compounds used in this disease must be able to pass through the blood-brain barrier. Chemotherapy regimens based on high-dose methotrexate are currently the standard of care for all patients who can tolerate such drugs. Autologous stem cell transplantation is indicated for malignant lymphomas in the relapsed/refractory setting.

Methods: Three patients, with a median age of 60 years, range 53-64, were diagnosed with primary CNS lymphoma, and treated with ibrutinib monotherapy in the Department of Hematology, Ion Chiricuta Clinical Cancer Center, Cluj-Napoca, Romania, between September 2018 and November 2020 All the patients were relapsed-refractory following high-dose methotrexate chemotherapy. We present our experience using ibrutinib monotherapy-based treatment as a bridge-to-transplant option on a single-center case series and a review of the literature in this field.

Results: Two of the patients were given ibrutinib as a second line therapy, both achieving complete remission and being eligible for an autologous stem cell transplantation. The third patient achieved a short remission using six cycles of systemic chemotherapy, but was started on ibrutinib monotherapy, with limited results.

Conclusion: Our data is limited, and these results should be confirmed by multicentric clinical trials and should be regarded as a single-center case series, with all its limitations. Still, it brings forward a new therapeutic option for this rare subtype of malignant lymphomas, which if left untreated has a dismal prognosis.