Allogeneic hematopoietic stem cell transplantation for adult patients with B-cell acute lymphoblastic leukemia harboring t(1;19)(q23;p13.3); comparison with normal karyotype.

There are few reports on allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult B-cell acute lymphoblastic leukemia (B-ALL) harboring t(1;19)(q23;p13.3). We used nationwide registry data of Japan for 2003-2016 to evaluate transplant outcomes and clarified prognostic factors among adult allo-HSCT recipients with B-ALL harboring t(1;19)(q23;p13.3) (n = 125). Compared with cytogenetically normal (CN) B-ALL patients (n = 1057), their 3-year overall survival (OS) rates were comparable (55.4% for t(1;19) and 54.4% for CN; P = 0.76). Considering only patients in first complete hematological remission (CR1), the 3-year OS rates remained comparable (70.5% for t(1;19) and 67.8% for CN; P = 0.86). For t(1;19) patients in CR1, minimal residual disease (MRD) at transplantation was associated with relatively worse outcomes. The 3-year OS rates were 43.6% for patients with MRD and 77.4% for those without it (P = 0.016). The 3-year relapse rates were 54.5% for patients with MRD and 12.8% for those without it (P < 0.001). Multivariate analyses revealed that MRD at transplantation was a significant risk factor for OS and relapse. In the high-intensity chemotherapy era, t(1;19)(q23;p13.3) did not have a poorer posttransplant prognosis than the normal karyotype. However, even for patients in CR1, MRD at transplantation was associated with comparatively worse OS and higher relapse rates.