Ibrutinib in Refractory Classic Hodgkin's Lymphoma

To the Editor: Ibrutinib is an oral, small-molecule Bruton's tyrosine kinase (BTK) inhibitor that has activity in chronic lymphocytic leukemia, mantle-cell lymphoma, and Waldenstrom's macroglobulinemia.1–3 We administered single-agent ibrutinib at a dose of 560 mg daily to two heavily pretreated patients who had primary refractory classic Hodgkin's lymphoma. Patient 1 was a 28-year-old woman who underwent haploidentical allogeneic hematopoietic-cell transplantation after receiving eight prior therapeutic regimens, including autologous hematopoietic-cell transplantation and brentuximab vedotin. Two months after the hematopoietic-cell transplantation, fevers, night sweats, and weight loss developed. Combined positron-emission tomography (PET) and computed tomography (CT) showed relapsed disease above and . . .