7024 Background: Philadelphia Chromosome-Positive (Ph+) disease is associated with a poor prognosis in acute lymphoblastic leukemia (ALL). Recent studies have shown that the eradication of minimal residual disease (MRD) in this population leads to improved survival outcomes. While hematopoietic stem cell transplantation (HSCT) has demonstrated clinical benefits in Ph+ ALL patients treated with the tyrosine kinase inhibitor (TKI) imatinib, its role is less clear with the use of more potent, newer-generation TKIs such as dasatinib. Methods: This was a retrospective study analyzing the impact of allogeneic HSCT on MRD status in Ph+ ALL patients treated with dasatinib. Patients were divided into 2 groups: those treated with chemotherapy plus dasatinib followed by allogeneic HSCT and those who received chemotherapy plus dasatinib alone. All patients underwent bone marrow biopsy with MRD analysis following induction therapy and subsequent re-evaluation of MRD status at day 100 post-transplant in the HSCT group and after further cycles of chemotherapy plus dasatinib in the non-transplant group. MRD-negative disease was defined as the absence of a BCR-ABL1 transcript by real-time quantitative polymerase chain reaction (qRT-PCR) with a sensitivity of 0.01%. Results: A total of 51 adult Ph+ ALL patients with MRD-positive disease following induction therapy were included. Twenty-seven patients (53%) were male and the median age at time of diagnosis was 42 years (range 23-68). There were 29 patients in the transplant group and 22 patients in the non-transplant group. When analyzing rates of MRD eradication, 18 (62%) patients in the transplant group were found to have MRD-negative disease at day 100 post-transplant compared to 7 (32%) patients in the non-transplant group who only received further cycles of chemotherapy plus dasatinib (risk ratio 0.56, 95% confidence interval 0.32-0.96, p = 0.048). Conclusions: In the era of newer-generation TKIs, allogeneic HSCT continues to have notable benefits in Ph+ ALL such as a significantly higher rate of MRD eradication as demonstrated in this study.
Donor-Derived CD19-Targeted T Cell Infusion Eliminates B Cell Acute Lymphoblastic Leukemia Minimal Residual Disease with No Response to Donor Lymphocytes after Allogeneic Hematopoietic Stem Cell Transplantation
