'Allogeneic marrow transplantation in children with acute leukemia: a practice whose time has gone': twenty years later

Comparable Outcomes of Matched Sibling Donor and Matched Unrelated Donor Stem Cell Transplantation in Children With Acute Leukemia in Argentina

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is an effective mode of consolidation therapy for children with high-risk acute leukemia. In high-income countries, match sibling donor (MSD) and match unrelated donor (MUD) HSCT have similar outcomes, but data are scarce in upper-middle-income countries. Our objective was to compare MSD and MUD HSCT outcomes for children with acute leukemia in Argentina.

PATIENTS AND METHODS

This was a single-institution retrospective cohort study. We included children with acute leukemia who underwent HSCT with either MSD or MUD between 2014 and 2019.

RESULTS

The study included 45 patients who received MSD (n=27) or MUD (n=18) for acute leukemia. Event-free survival was not significantly different between MSD (62.3±10.7%) versus MUD (54.2±15.0%; P=0.54) at 5 years. Similarly, there was no significant difference in 5-year overall survival between MSD (71.9±9.8%) versus MUD (65.1±13.5%; P=0.38). The cumulative incidence of treatment-related mortality (P=0.31), cumulative incidence of relapse (P=0.99), and proportion with acute-graft-versus-host disease (P=0.76) and chronic-graft-versus-host disease (P=0.68) were also not significantly different.

CONCLUSIONS

In Argentina, we did not show significant differences in outcomes between MSD and MUD HSCT for children with high-risk leukemia. Future work should focus on strategies to reduce the relapse risk in children with high-risk leukemia in upper-middle-income countries.

Early bacterial and fungal infection in children receiving allogeneic stem cell transplantation for acute lymphoblastic leukemia in Argentina

Infections are important complications associated with allogeneic HSCT. Describing infection rates in low- and middle-income countries provides data to infer efficacy of supportive care practices in these settings. In this retrospective cohort study, we included patients (age ≤ 18 years) who underwent a first allogeneic HSCT for ALL in a single center in Argentina between 1998 and 2016. The primary outcome was sterile site bacterial infection. Secondary outcomes were proven or probable invasive fungal infection, TRM, and infectious deaths. There were 68 allogeneic HSCT recipients with ALL included in this analysis. Overall, 17 (25.0%) experienced at least one sterile site bacterial infection and 10 (14.7%) experienced at least one proven or probable invasive fungal infection. The TRM rate was 19.1%, and 3 (4.4%) patients died of infection. In a middle-income country center in Argentina, pediatric allogeneic HSCT infection rates, TRM, and infection-related mortality were comparable to high-income countries. These data support continuation of allogeneic HSCT programs in similar resource-limited settings provided that adequate supportive care and monitoring of outcomes can be performed.

Better early outcome with enteral rather than parenteral nutrition in children undergoing MAC allo-SCT

There is no consensus on the type of nutritional support to introduce in children undergoing allogeneic stem cell transplantation (allo-SCT) after myeloablative conditioning (MAC). This retrospective, multicenter, observational study compared the early administration of enteral nutrition (EN group, n = 97) versus parenteral nutrition (PN group, n = 97) in such patients with matching for important covariates. The primary endpoint was the study of day 100 overall mortality. The early outcome at day 100 was better in EN group regarding mortality rate (1% vs. 13%; p = 0.0127), non relapse mortality (1% vs. 7%; p = 0.066), acute GVHD grades II-IV (37% vs. 54%; p = 0.0127), III-IV (18% vs. 34%; p = 0.0333) and its gut localization (16% vs. 32%; p = 0.0136). Platelet engraftment was better in EN group than in PN group for the threshold of 20 G/L (97% vs. 80% p < 0.0001) and 50 G/L (92% vs. 78%, p < 0.0001). The length of stay was shorter in EN group (28 vs. 52 days, p < 0.0001). There were no differences between the two groups regarding the polynuclear neutrophil engraftment, infection rate or mucositis occurrence. These results suggest that, in children undergoing MAC allo-SCT, PN should be reserved to the only cases when up-front EN is insufficient or impossible to perform.

Improvement of overall survival after allogeneic hematopoietic stem cell transplantation for children and adolescents: a three-decade experience of a single institution

Allogeneic stem cell transplantation (allo-SCT) has become an essential component of the treatment for a variety of diseases in pediatric patients. During the past decades, advances in the transplant technology, availability of hematopoietic stem cells and supportive care not only have resulted in improved outcomes, but also have expanded the transplant options. However, these features have been studied mainly in adult populations. This investigation analyzed changes in patient profile, transplantation, graft characteristics and outcome among 250 children and adolescent patients who received allo-SCT in a single center between 1983 and 2010. In the 2000-2010, compared with the 1983-1999 period, a significantly higher 5-year overall survival (64% versus 52%, P=0.03) was observed together with a significant decrease of non-relapse mortality (27% versus 9%, P=0.0002). The progression-free survival was comparable between the two periods (49% versus 57%; P=0.17). The 5-year cumulative incidence of relapse was 24% between 1983 and 1999, and 34% between 2000 and 2010 (P=0.08). Major advances in supportive care practice have been made over the past decade, resulting in a significant survival benefit for the pediatric population undergoing allo-SCT. However, post-transplant relapse remains the leading cause of failure of this therapeutic approach, and preventing relapse represents a major challenge today.

Stem-Cell Transplantation in Children With Acute Lymphoblastic Leukemia: A Prospective International Multicenter Trial Comparing Sibling Donors With Matched Unrelated Donors—The ALL-SCT-BFM-2003 Trial

Purpose

Although hematopoietic stem-cell transplantation is widely performed in children with high-risk acute lymphoblastic leukemia (ALL), the influence of donor types is poorly understood. Thus, transplantation outcomes were compared in the prospective multinational Berlin-Frankfurt-Muenster (BFM) study group trial: ALL-SCT-BFM 2003 (Allogeneic Stem Cell Transplantation in Children and Adolescents with Acute Lymphoblastic Leukemia).

Patients and Methods

After conditioning with total-body irradiation and etoposide, 411 children with high-risk ALL received highly standardized stem-cell transplantations during the first or later remissions. Depending on donor availability, grafts originated from HLA-genoidentical siblings or from HLA-matched unrelated donors who were identified and matched by high-resolution allelic typing and were compatible in at least 9 of 10 HLA loci.

Results

Four-year event-free survival (± standard deviation [SD]) did not differ between patients with transplantations from unrelated or sibling donors (0.67 ± 0.03 v 0.71 ± 0.05; P = .405), with cumulative incidences of nonrelapse mortality (± SD) of 0.10 ± 0.02 and 0.03 ± 0.02 (P = .017) and relapse rates (± SD) of 0.22 ± 0.02 and 0.24 ± 0.04 (P = .732), respectively. Among recipients of transplantations from unrelated donors, no significant differences in event-free survival, overall survival, or nonrelapse mortality were observed between 9/10 and 10/10 matched grafts or between peripheral blood stem cells and bone marrow. The absence of chronic graft-versus-host disease had no effect on event-free survival. Engraftment was faster after bone marrow transplantation from siblings and was associated with fewer severe infections and pulmonary complications.

Conclusion

Outcome among high-risk pediatric patients with ALL after hematopoietic stem-cell transplantation was not affected by donor type. Standardized myeloablative conditioning produced a low incidence of treatment-related mortality and effective control of leukemia.

Beyond CD19: Opportunities for Future Development of Targeted Immunotherapy in Pediatric Relapsed-Refractory Acute Leukemia

Chimeric antigen receptor (CAR) T cell therapy has been used as a targeted approach in cancer therapy. Relapsed and refractory acute leukemia in pediatrics has been difficult to treat with conventional therapy due to dose-limiting toxicities. With the recent success of CD 19 CAR in pediatric patients with B cell acute lymphoblastic leukemia (ALL), this mode of therapy has become a very attractive option for these patients with high-risk disease. In this review, we will discuss current treatment paradigms of pediatric acute leukemia and potential therapeutic targets for additional high-risk populations, including T cell ALL, AML, and infant ALL.

Minimal residual disease after induction is the strongest predictor of prognosis in intermediate risk relapsed acute lymphoblastic leukaemia - long-term results of trial ALL-REZ BFM P95/96

PURPOSE

This blinded prospective study was performed to optimise the risk assessment of children with a late isolated, combined or an early combined bone marrow (BM) relapse of precursor B-cell acute lymphoblastic leukaemia (ALL). The aim was to develop a reliable tool to identify patients with an intermediate risk relapse who are in need of haematopoietic stem cell transplantation (HSCT).

METHODS

Included were 80 children and adolescents with first intermediate risk BM relapse of ALL recruited in trial ALL-REZ BFM P95/96. We assessed the prognostic value of minimal residual disease (MRD) after induction therapy quantified by PCR using leukaemia clone-specific T-cell receptor/immunoglobulin gene rearrangements.

RESULTS

Molecular good responders (MRD < 10(-3), n=46) had a probability of event-free survival (pEFS) at 10 years of 76% standard error (SE) ± 6% and a cumulative incidence of second relapse (CIR) at 10 years of 21% SE ± 6%; pEFS of molecular poor responders (MRD ≥ 10(-3), n=34) at 10 years was 18% SE ± 7% and CIR 61% SE ± 9% (p<0.001). Cox regression analysis revealed MRD after induction to be the strongest independent prognostic parameter with a 6.6-fold increased risk (95% confidence interval 3.3-13.5, p<0.001) for molecular poor responders to suffer a subsequent adverse event compared to good responders.

CONCLUSION

In patients with intermediate risk BM relapse of ALL, low MRD after induction is associated with an excellent long-term prognosis with conventional chemo-/radiotherapy whereas patients with insufficient response have an extremely poor prognosis. Therefore, in the subsequent trial ALL-REZ BFM 2002, MRD is used to allocate molecular good responders to conventional post-induction therapy and molecular poor responders to allogeneic HSCT.

Access to allogeneic hematopoietic SCT for patients with MDS or relapsed AML treated according to protocols of the Dutch Childhood Oncology Group

To investigate whether all patients in need of an allogeneic hematopoietic SCT (HSCT) are offered one, we retrospectively investigated the policy for all children diagnosed with myelodysplastic syndrome (n=90) or relapsed AML (n=75) between 1998 and 2008. These children are registered at diagnosis and treated according to protocols of the Dutch Childhood Oncology Group, which provides accurate disease incidence data and protocol-indicated appropriateness for HSCT. For 48 (30%) patients, a family donor was identified; for 90 (57%) patients, an unrelated donor (UD) search was performed; and for 21 (13%) patients, no UD search was initiated. Reasons for not initiating an UD search include: progressive disease (n=10), conserve quality of life (n=1), stable disease (n=3), immunosuppressive therapy (n=2), patient death (n=3), patient lives abroad (n=1) and second relapse (n=1). On the basis of the time interval between date of diagnosis and date of death/last follow-up, for eight (5%) patients, it may be questioned why an UD search was not performed. The fact that 95% of all children are given the option of an allogeneic HSCT is encouraging and reasons not to transplant seem fair in most cases.