TKI Therapy Based on Molecular Monitoring in Allogeneic-HSCT Recipients With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia

TKI Therapy Based on Molecular Monitoring in Allogeneic-HSCT Recipients With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia

Tyrosine Kinase Inhibitor Therapy Based on Molecular Monitoring of BCR/ABL Transcript Levels in Allogeneic Hematopoietic Stem Cell Transplant Recipients With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia

Peking University People's Hospital, Guangxi Medical University, Guangdong Provincial People's Hospital, Guangzhou General Hospital of Guangzhou Military Command, Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, Third Affiliated Hospital, Sun Yat-Sen University

The purpose of this study is to evaluate the efficacy of tyrosine kinase inhibitor(TKI) therapy based on molecular monitoring of BCR/ABL levels in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL)undergoing allogeneic hematopoietic stem cell transplantation(allo-HSCT).

Philadelphia chromosome (Ph) is a reciprocal chromosomal translocation t(9;22）(q34;q11), which leads to the formation of the BCR/ABL oncogene. Ph is the most frequent cytogenetic abnormality in ALL characterized by poor outcome. With the BCR/ABL protein TKI, imatinib, in the combination chemotherapy regimes for newly diagnosed Ph+ ALL, more than 95% of patients can achieve complete remission(CR). Several studies have shown decreased relapse rates and improved disease-free survival for patients with imatinib-based treatment prior to allo-HSCT. However, the efficacy of maintenance therapy with imatinib after transplant for Ph+ ALL patients is still uncertain. In addition, acquired resistance to imatinib is frequently caused by point mutations in BCR/ABL that inactivate imatinib. Detection of minimal residual disease (MRD) after transplant is associated with an increased risk of relapse. Reverse transcription-polymerase chain reaction (RT-PCR) is a sensitive method for detecting low-level BCR/ABL transcripts to assess MRD in Ph+ ALL. It has been corroborated by several reports that detection of MRD after SCT was predictive of imminent relapse. In this study, we will evaluate the safety and efficacy of TKI therapy, when initiating treatment based on BCR-ABL transcript levels after allo-HSCT.

Philadelphia Chromosome Positive Acute Lymphocytic Leukemia, Stem Cell Transplantation, Minimal Residual Disease

Philadelphia chromosome, Acute lymphoblastic leukemia, Allogeneic hematopoietic cell transplantation, Minimal residual disease, Tyrosine kinase inhibitor

Treatment with TKI will be initiated if the level of BCR-ABL transcript in the bone marrow is detectable and transcript levels increased for two consecutive tests. TKIs will be given for patients without BCR/ABL mutations and sensitive TKIs will be given for those with mutations.

Imatinib was given at a dose of 400mg/d or 600mg/d, dasatinib at a dose of 100mg/d or 140mg/d, and nilotinib at a dose of 400mg twice daily. If the patients had T315I mutations, ponatinib will be given. If the BCR/ABL levels increased or did not decrease after one month's use of TKI, donor lymphocyte infusion will be given and the TKI drugs will be modulated. If the patients experienced hematologic relapse, they will withdraw from the study.

A post-transplant relapse is defined as hematological relapse, extramedullary involvement of leukemia and cytogenetic relapse.

Inclusion Criteria: A patient age of 14-65 years Allo-HSCT recipient with ph+ ALL Subjects (or their legally acceptable representatives) must have signed an informed consent document indicating that they understand the purpose of and procedures required for the study and are willing to participate in the study. Exclusion Criteria: Any abnormality in a vital sign (e.g., heart rate, respiratory rate, or blood pressure) patients with hematological relapse, extramedullary involvement of leukemia Patients with any conditions not suitable for the trial (investigators' decision)

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