Olverembatinib combined with inotuzumab ozogamicin in relapsed refractory Philadelphia chromosome-positive acute lymphoblastic leukemia: A case report.

Rationale: Patients with relapsed and refractory Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) with the T315I mutation are at higher risk of relapse and have shorter overall survival.

Patient Concerns: A 31-year-old man presented to the hematology department with intermittent fever and pancytopenia. He was diagnosed with Ph+ acute lymphoblastic leukemia and experienced 2 relapses during treatment. A drug-resistant T315I mutation was detected in the ABL kinase region during review.

Diagnoses: Morphological examination of the bone marrow revealed approximately 93.5% lymphoid blast. Flow cytometric analysis confirmed the diagnosis of common B-cell ALL with the following phenotype: CD34, CD45dim, CD19, CD10, cCD79a, CD58dim, CD81dim, cTdT, HLA-DR, CD22dim, CXCR4, CD33dim, CD20, CD25, CD13, CD123. The examination of the ABL kinase region mutation suggested a T315I mutation.

Interventions: Olverembatinib, a third-generation TKI drug, was administered in combination with inotuzumab ozogamicin to treat the disease.

Outcomes: The patient achieved morphological remission with a negative flow cytometry MRD test, and the quantification of BCR-ABL transcripts was 0% after 1 cycle of therapy.

Lessons: The third-generation TKI olverembatinib has been proven to be effective in CML patients with the T315I mutation, and it may also be effective in Ph+ acute lymphoblastic leukemia. Some new immune drugs have also shown improvement in the remission rate. Combination therapy with olverembatinib and Ino can achieve a complete molecular response in patients with relapsed and refractory Ph+ ALL with the T315I mutation.