Hematopoietic Cell Transplantation for Richter Syndrome.

Treatment combining chemotherapy with immunotherapy as well as novel targeted therapies have shown limited efficacy in Richter syndrome. Overall response rates after chemoimmunotherapy range from 43% to 67%, but remissions are generally short-lived. In chronic lymphocytic leukemia (CLL), allogeneic hematopoietic cell transplantation (all-HCT) is considered a potentially curative treatment modality, yielding 3-year overall survival rates exceeding 50% and a plateau in survival curves. In Richter syndrome, efficacy of allo-HCT depends on demonstrating an objective response (complete remission or partial response) before allografting, with resulting 3-year survival rates of 41% to 75%. On the other hand, the efficacy of autologous HCT is limited, especially when considering that patients autografted for Richter syndrome might relapse with CLL in 35% of cases. Notwithstanding the scarcity of published data, we recommend that patients with Richter syndrome should be referred to transplant centers as soon as the diagnosis is confirmed to evaluate their candidacy for allo-HCT. Establishing a clonal relationship to CLL is important considering the more aggressive disease course in clonally related Richter syndrome. Moreover, achievement of a complete remission or partial response to salvage therapy must be a prerequisite before moving forward with allografting for Richter syndrome. Patients who fail to demonstrate an objective response to salvage therapy should be considered for enrollment in clinical trials.