Post-Stem Cell Transplant Maintenance for Pediatric Acute Leukemias: Insights from a Brazilian Institution with a Latin American Perspective

Carla Nolasco Monteiro Breviglieri ^1* Roseane Gouveia Vasconcelos ^1,2 Valeria Cortez Ginani ^1,2 Camila Noronha Santos ¹ Milena Reis Santos de Oliveira ¹ Anna Beatriz Willemes Batalha ¹ Gabriella Sayuri de Alencar ¹ Edna Harumi Goto ¹ Juliana Francielle Marques ¹ Marcia Puato Vieira Pupim ¹ Adriana Seber ^1,2

• ¹ Hospital Samaritano de São Paulo, Higienópolis, Brazil
• ² Pediatric Oncology Institute, GRAACC Hospital, São Paulo, São Paulo, Brazil

In resource-limited countries, access to advanced therapies such as CAR T-cell therapy, other immunotherapies, and even medications with proven benefits are often unattainable. Clinical trials face logistical, regulatory, and financial challenges, with pediatric populations frequently excluded or experiencing delays of a decade or more before therapies become accessible. This gap highlights the need for alternative strategies to address high relapse risks in pediatric acute leukemia following stem cell transplant. This study presents the experience of a Brazilian institution implementing posttransplant maintenance therapies, including venetoclax, decitabine, azacitidine, blinatumomab, donor lymphocyte infusion (DLI), and other targeted approaches. These therapies, while not widely accessible, were achieved through collaborative efforts and special approvals, reflecting persistent barriers in resource-limited settings. Despite these challenges, the interventions were generally welltolerated, potentially reducing the risk of relapse, and deserve future formal clinical trials to address these strategies. The findings provide valuable insights for improving outcomes in regions with similar constraints, underscoring the importance of pragmatic and adaptable strategies in low-and middle-income countries.