HOUSTON – Haploidentical stem cell transplantation (Haplo-HSCT) outperforms chemotherapy for the treatment of adults with acute lymphoblastic leukemia (ALL) in first complete remission, findings from a prospective multicenter trial suggest.
The 2-year leukemia-free survival (LFS) was about 70% in 49 patients in first remission who received haplo-HSCT vs. 40% in 40 patients who received chemotherapy, and 2-year overall survival (OS) was about 80% vs. 50% in the groups, respectively,, of Peking University People’s Hospital in Beijing reported at the Transplantation & Cellular Therapy Meetings.
“This result is comparable to results of our previous reports,” he said at the meeting held by the American Society for Blood and Marrow Transplantation and the Center for International Blood and Marrow Transplant Research.
He noted that the findings also support those from other institutions.
Study subjects initially included 112 newly diagnosed standard-risk ALL patients aged 18-39 years without high-risk features who achieved complete remission (CR) after one or two cycles of induction. They were consecutively enrolled at five centers in China, including high-volume centers, between July 2014 and June 2017 and were followed for a median of 24.6 months.
Subjects without a suitable HLA-matched sibling donor (MSD) or HLA-matched unrelated donor after two cycles of consolidation with hyper-CVAD chemotherapy were eligible for haplo-HSCT or further hyper-CVAD chemotherapy.
The final analysis included 89 patients after 23 were excluded because of early relapse (6 patients) or a decision to undergo MSD HSCT (16 patients), or unrelated donor-HSCT (1 patient), Dr. Lv said, noting that landmark analysis was used when comparing the outcomes of patients receiving haplo-HSCT with those receiving chemotherapy.
Multivariate analysis with adjustment for a propensity score calculated for each patient showed that treatment (haplo-HSCT vs. chemotherapy) independently predicted LFS (hazard ratio, 0.388), OS (HR, 0.346), and cumulative incidence of relapse (CIR; HR, 0.247). Minimal residual disease (MRD) positivity after the first consolidation was an independent risk factor for LFS (HR, 2.162) and CIR (HR, 3.667). Additionally, diagnosis (T- vs. B-cell) was an independent risk factor for OS (HR, 2.267), Dr. Lv said, adding that nonrelapse mortality was similar in the groups in the propensity score–adjusted analysis.
The findings overall show that haplo-HSCT has variable impact on survival in standard-risk ALL, when compared with traditional chemotherapy, with subgroup analyses showing MRD-positive patients deriving the greatest benefit, he said. Future studies are planned to look more closely at MRD-positive disease and the possible benefits of postponing transplant until the second CR.
At its meeting, the American Society for Blood and Marrow Transplantation announced a new name for the society: American Society for Transplantation and Cellular Therapy (ASTCT).
Dr. Lv reported having no financial disclosures.
SOURCE: Lv M et al. TCT 2019, .