Refractory pancytopenia upon initiation of asciminib in tyrosine kinase inhibitor-resistant chronic myeloid leukemia.

Asciminib, a "Specifically Targeting the ABL Myristoyl Pocket" inhibitor, is a new drug in the treatment of tyrosine kinase inhibitor (TKI)-resistant chronic myeloid leukemia (CML). Hemocytopenias associated with asciminib are common adverse events documented by clinical trials. We report a case of precipitous-onset pancytopenia with the initiation of asciminib treatment in a patient with TKI-resistant CML. This case had a confounding array of laboratory findings that evidenced a drug-induced hemophagocytic component. We hope that our case stimulates further reporting of similar cases to enhance the understanding of the pathophysiology underlying asciminib-induced hemocytopenias.