T315I-mutated chronic myeloid leukemia with blast crisis relapse 10 years after allo-HSCT: A case report of second transplantation combined with olverembatinib maintenance therapy.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the presence of the Philadelphia chromosome and the resulting fusion proteins with abnormal tyrosine kinase activity. The treatment of CML includes allogeneic hematopoietic stem cell transplantation (allo-HSCT) and TKI drug therapy. The BCR::ABL1 T315I mutation in CML leads to resistance to first- and second-generation tyrosine kinase inhibitors (TKIs), but is sensitive to two third-generation TKIs, olverembatinib and ponatinib. Olverembatinib, an oral third-generation BCR::ABL1 TKI, has preclinical activity against T315I-mutated CML. Here, we present a case of a CML patient with the T315I mutation who experienced late relapse with blast crisis 10 years after allo-HSCT. Following hematologic recovery and achievement of major molecular response (MMR) through induction therapy, the patient underwent a second allo-HSCT from his haploidentical sister. After successful engraftment, the patient received regular consolidation maintenance therapy with olverembatinib.