Abstract Introduction: The growing complexity of health systems limits equitable access to hematopoietic stem cell transplantation (HSCT). The availability of haploidentical donors in over 95% of cases and the use of reduced-intensity conditioning (RIC), which in adults has yielded results comparable to myeloablative conditioning, provides an alternative to expand access and improve outcomes in the region. Objective: To describe the outcomes in pediatric patients undergoing haploidentical HSCT (Haplo-HSCT) with graft-versus-host disease (GVHD) prophylaxis using post-transplant cyclophosphamide (PTCy) and a RIC regimen. Methods: A retrospective study was conducted at a single center, including pediatric patients under 14 years old with hematological malignancies, enrolled in a prospective registry between January 2015 and April 2024. All patients received related Haplo-HSCT with peripheral blood stem cells. A RIC with Flu/Cy/Bu8 or Flu/Cy/Mel140 + 2 Gy total body irradiation (TBI) was used. GVHD prophylaxis was PTCy based. Results: Forty-seven patients were included, with a median age of 8 years (1–14), of whom 92% had acute leukemia. Sixty percent were in second remission, and 40% had received three or more prior treatment lines. In 60% of cases, the donor was the father, with a median age of 31 years. Two patients (4%) experienced primary graft failure, both with the Flu/Cy/Bu8 regimen. Eighty-five percent received conditioning with Flu/Cy/Mel140 and 2 Gy radiotherapy. The median time to neutrophil engraftment was 14 days, and 15 days for platelets. The cumulative incidence of acute graft-versus-host disease (aGVHD) grades II-IV at day 100 was 36%, and grades III-IV was 12.7%. The cumulative incidence of moderate to severe chronic GVHD at 12 months was 21%. Non-relapse mortality (NRM) at one year was 14.8%, and the cumulative incidence of relapse at two years was 21.9%. Overall survival (OS) was 79% at one year and 68% at two years, while event-free survival (EFS) at two years was 63%. Conclusion: The outcomes of this pediatric cohort undergoing haploidentical HSCT with PTCy, using a reduced-intensity conditioning regimen and peripheral blood hematopoietic stem cells, demonstrated acceptable toxicity, overall survival, and event-free survival. Sharing this experience contributes to collective knowledge, highlights the challenges faced, and may motivate other teams in similar settings to implement this therapeutic strategy.
Colunga‐Pedraza et al. (Mon,) studied this question.