Hodgkin Lymphoma Transformation of Chronic Lymphocytic Leukemia Under Ibrutinib Therapy: Chance Association or Therapy-related?

Abstract
The established treatment algorithms for chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) are currently challenged by novel classes of drugs, with ibrutinib being one of the most effective. Published data suggest that patients with early progression under ibrutinib often emerge as having Richter's transformation (RT) with a rapidly fatal prognosis, mostly developing diffuse large B-cell lymphoma (DLBCL). In this respect, it is known that RT to large DLBCL occurs in about 5% of patients with CLL during the disease course and less frequently to Hodgkin lymphoma (HL). Here, we report a patient with CLL who presented with HL transformation while still receiving therapy with ibrutinib stressing the need for clinical vigilance in any case with persisting or enlarging lymph nodes during treatment with this agent, as prompt modification of therapy is most important.