LAUSR

Key Points Question To what extent is clonal hematopoiesis (CH) associated with treatment response and toxicity among patients with metastatic cancer who receive chemotherapy or immune checkpoint blockade? Findings In this cohort study of 633 patients with metastatic esophagogastric and colorectal cancers, one-third of patients had CH, and half of these alterations were present in putative CH driver genes (CH-PD). The presence of CH and CH-PD were not associated with differences in progression-free survival, baseline leukocyte counts, or increased need for granulocyte colony-stimulating factor support. Meaning Detection of CH or CH-PD does not appear to be associated with progression-free survival during chemotherapy or immune checkpoint blockade, nor with leukocyte recovery, suggesting limited utility of CH in solid tumor clinical decision-making.