Abstract
Chimeric antigen receptor T-cell therapy (CAR T-cell) is a new treatment option for relapsed and/or refractory (R/R) chronic lymphocytic leukemia (CLL). Novel therapies including Bruton's tyrosine kinase inhibitors (BTK), covalent or non-covalent, and an inhibitor of the B-cell leukemia/lymphoma 2 protein (BCL-2), venetoclax, have replaced chemoimmunotherapy (CIT) regimens in the front-line and the R/R setting, and have relegated allogeneic hematopoietic cell transplantation (allo-HCT) to later treatment stages. Updating the 2016 clinical practice recommendations on allo-HCT in CLL is necessary to help guide contemporary clinical practice. A panel of 18 physicians with diverse expertise across different CLL treatment modalities and one methodologist participated in this effort. Any recommendation receiving ≥ 70% votes was considered a consensus. CAR T-cell therapy is recommended for patients not responding or relapsing after at least 2 lines of therapy consisting of a covalent BTK inhibitor and a BCL-2 inhibitor. In addition, CAR T-cell therapy is recommended for patients who subsequently received a non-covalent BTK inhibitor in the third-line or later setting, regardless of response. CAR T-cell therapy is also recommended in CLL relapsing after an allo-HCT, assuming that patients are fit for the procedure. In those CLL patients who are candidates, allo-HCT is recommended if disease is R/R to CAR T-cell therapy provided that an objective response is demonstrated prior to the allograft. Allo-HCT is also recommended in patients with clonally-related Richter transformation (RT) after demonstrating an objective response to front-line CIT or other treatments. CAR T-cell therapy is recommended in R/R RT. We emphasize the importance of enrolling patients in clinical trials whenever available to continue to advance the field and improve prognosis of R/R CLL. We acknowledge that there are unique clinical scenarios not covered herein which may require a case-by-case approach.