Hematopoietic Stem Cell Transplantation Based on Minimal Residual Disease with a Unified Conditioning Regimen Comprising Total Body Irradiation, Etoposide and Cyclophosphamide: Results from the JPLSG ALL-R08-II Trial, the First Nationwide Prospective Study for Children with Intermediate-Risk Relapsed Acute Lymphoblastic Leukemia in Japan

Hidemi Toyoda; Hideaki Ueki; Chitose Ogawa; Hiroaki Goto; Masanori Nishi; Junko Yamanaka; Shinji Mochizuki; Takuro Nishikawa; Tadashi Kumamoto; Ritsuo Nishiuchi; Atsushi Kikuta; Shohei Yamamoto; Shunji Igarashi; Atsushi Sato; Toshinori Hori; Akiko Saito; Tomoyuki Watanabe; Takao Deguchi; Atsushi Manabe; Keizo Horibe

doi:10.22541/au.167514670.04452922/v1

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Hematopoietic Stem Cell Transplantation Based on Minimal Residual Disease with a Unified Conditioning Regimen Comprising Total Body Irradiation, Etoposide and Cyclophosphamide: Results from the JPLSG ALL-R08-II Trial, the First Nationwide Prospective Study for Children with Intermediate-Risk Relapsed Acute Lymphoblastic Leukemia in Japan

Hidemi Toyoda,
Hideaki Ueki,
Chitose Ogawa,
Hiroaki Goto,
Masanori Nishi,
Junko Yamanaka,
Shinji Mochizuki,
Takuro Nishikawa,
Tadashi Kumamoto,
Ritsuo Nishiuchi,
Atsushi Kikuta,
Shohei Yamamoto,
Shunji Igarashi,
Atsushi Sato,
Toshinori Hori,
Akiko Saito,
Tomoyuki Watanabe,
Takao Deguchi,
Atsushi Manabe,
Keizo Horibe

Abstract

Background: In children with intermediate-risk relapsed acute lymphoblastic leukemia (ALL), allogeneic hematopoietic stem cell transplantation (allo-HSCT) has markedly improved the outcome of patients with poor minimal residual disease (MRD) response. However, there is no consensus on the optimal conditioning regimen for allo-HSCT. Procedure: We prospectively analyzed the efficacy and safety of allo-HSCT with a unified conditioning regimen for children with intermediate-risk relapsed ALL, based on MRD in the bone marrow after induction, in the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) ALL-R08-II nationwide cohort. The conditioning regimen for allo-HSCT comprised total body irradiation (TBI), etoposide (ETP) and cyclophosphamide (CY) (UMIN000002025). Results: Twenty patients with post-induction MRD ≥ 10 ⁻³ and two with MRD that could not be evaluated underwent allo-HSCT. Engraftment was confirmed in all patients. No transplantation-related mortality was observed. The 3-year event-free survival and overall survival after transplantation were 86.4% ± 7.3% and 95.5% ± 4.4%, respectively. Conclusion: Allo-HSCT based on post-induction MRD with TBI + ETP + CY conditioning was highly effective and feasible for Japanese children with intermediate-risk relapsed ALL.