Hematopoietic stem cell transplantation for pediatric acute promyelocytic leukemia in Japan

Abstract

Background The number of hematopoietic stem cell transplantation (HSCT) procedures performed for pediatric acute promyelocytic leukemia (APL) has decreased in the all‐trans retinoic acid (ATRA) era. Although HSCT is still widely adopted as part of salvage therapy for relapsed patients, there is no general consensus about the optimal transplant type (autologous [auto‐HSCT] or allogeneic HSCT [allo‐HSCT]). Procedures We retrospectively reviewed the clinical data of 95 childhood APL patients who underwent their first HSCT between 1990 and 2014. Of the 95 patients, 40 (42%), 41 (43%), and 3 (3%) underwent HSCT procedures after achieving their first complete remission (CR1), CR2, and CR3, respectively, and 11 (12%) underwent HSCT while in a non‐CR state. Results The non‐CR group exhibited significantly worse five‐year overall survival (5yOS) and disease‐free survival (5yDFS) (5yOS: 46%; 5yDFS: 46%) than the CR1 (5yOS: 80%; 5yDFS: 78%) and CR2 + CR3 groups (5yOS: 81%; 5yDFS: 76%) (P = 0.013 and P < 0.01, respectively). Of the patients treated in CR2, no significant differences in 5yOS or the five‐year cumulative incidence of relapse (5yRI) were detected between the auto‐HSCT and allo‐HSCT groups (5yOS: 85%, vs 78%, P = 0.648; 5yRI: 9%, vs 11%, P = 0.828). Among the patients who underwent allo‐HSCT in CR2, those with matched sibling donors displayed a significantly higher 5yRI (33%) than those with other types of donors (0%, P = 0.015). Conclusions Even after relapsing, childhood APL can be cured with HSCT if CR is achieved. These findings demonstrate that achieving CR followed by HSCT is the preferred strategy for treating children with relapsed or refractory APL.

Pediatric Autologous Hematopoietic Stem Cell Transplantation: Safety, Efficacy, and Patient Outcomes. Literature Review

“…The largest pediatric APL series (95 children treated between 1990 and 2014) was reported by the Japan Society of Hematopoietic Cell Transplantation (JSHCT); 40 children underwent transplant in CR1, 41 in CR2, 3 in CR3 and 11 with persistent disease. 26 Both auto- and allo-HSCT were effective in children transplanted in CR2 (5-year OS 85% vs 78%; DFS 76% vs 75%). Data on salvage induction therapy and pre-transplant molecular response were not reported in this study.…”

Has Hematopoietic Stem Cell Transplantation a Role in the Treatment of Children and Adolescents With Acute Promyelocytic Leukemia?

“…A large number of pediatric APL patients (95 children; aged 0–19) transplanted between 1990 and 2014 were identified in the Japan Society of Hematopoietic Cell Transplantation (JSHCT) registry. 27 Forty of them underwent auto- or allo-HSCT in first CR and 55 in other settings (second CR: 41; third CR: 3 and no-CR: 11). HSCT was included in the front-line treatment before ATRA-era; it was subsequently adopted as a treatment for patients in second CR.…”

Update on acute promyelocytic leukemia in the pediatric population

“…In hematopoietic stem cell transplantation, good prognoses have been reported in the second remission in adult patients. Regarding pediatric patients, Yamamoto et al 21 conducted a retrospective study analyzing data from pediatric transplanted patients in Japan. They found that transplant patients without having presented a remission had the worst survival rates (5yOS) at 5 years.…”

“…On the other hand, it was found that, although an autologous transplant is recommended in second remission, there were no significant differences in the mortality rates related to transplantation and the incidence of relapse, between autologous and allogeneic transplants. 21…”