Olverembatinib combined with blinatumomab in treating T315I-mutated Philadelphia chromosome-positive acute lymphoblastic leukemia: two-case report

ABL tyrosine kinase inhibitors (TKIs) act an irreplaceable role in the management of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). The treatment of these diseases has been revolutionized by the application of immunotherapeutic modalities. However, diseases with ABL kinase domain mutation T315I are resistant to the majority of TKIs, which is responsible for treatment failure. Olverembatinib is a third-generation TKI that has been approved for the treatment of T315I-mutated chronic myeloid leukemia (CML) in China; its usage in Ph+ ALL needs further exploration. Here, we present two cases with relapsed T315I mutation Ph+ ALL who received the combination regimen of blinatumomab and olverembatinib. This regimen, which has not been reported yet, was safe and effective as the patients achieved minimal residual disease (MRD) negative after 1 cycle of therapy. The management of these cases provides evidence of this new chemo-free regimen as an efficient approach for relapsed or refractory(R/R)Ph+ ALL.

Contribution of BCR-ABL molecular variants and leukemic stem cells in response and resistance to tyrosine kinase inhibitors: a review

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm generated by reciprocal chromosomal translocation, t (9; 22) (q34; q11) in the transformed hematopoietic stem cell. Tyrosine kinase inhibitors (TKIs) target the mature proliferating BCR-ABL cells, the major CML driver, and increase overall and disease-free survival. However, mutant clones, pre-existing or due to therapy, develop resistance against TKIs. BCR-ABL1 oncoprotein activates various molecular pathways including the RAS/RAF/MEK/ERK pathway, JAK2/STAT pathway, and PI3K/AKT/mTOR pathway. Stimulation of these pathways in TKI resistant CML patients, make them a new target. Moreover, a small proportion of CML cells, leukemic stem cells (LSCs), persist during the TKI therapy and sustain the disease in the patient. Engraftment of LSCs in the bone marrow niche and dysregulation of miRNA participate greatly in the TKI resistance. Current efforts are needed for determining the reason behind TKI resistance, identification, and elimination of CML LSC might be of great need for cancer cure.

Mutation Analysis in Chronic Myeloid Leukemia Patient in Chronic Phase on Imatinib Having Delayed Achievement of Milestones or Loss of Response

Tyrosine kinase inhibitors (TKI's) are currently the drug of choice for management of chronic myeloid leukemia. Imatinib is the most commonly used first line TKI in India. Mutations leading to resistance to imatinib are the most common cause for imatinib failure. We studied pattern of kinase domain mutations in 40 patients of CML who either lost their response or did not achieve it in defined timepoints. Loss of molecular response was the most common indication for asking mutation analysis. Sixteen patients were found to have detectable mutations. M351T was the most common tyrosine kinase mutation followed by Y253H and H396R. Two patients had 2 mutations simultaneously. M351T is the most common mutation in our patient population.