Clinical Outcomes of Unrelated Umbilical Cord Blood Graft vs. Haploidentical Donor Transplantation: Critical Issues for an Adequate Comparison

Unrelated umbilical cord blood (UCB) and haploidentical grafts have been used for allogeneic hematopoietic stem and progenitor cell (HSPC) transplantation in patients without a related or non-related human leukocyte antigen (HLA)-matched donor. The less stringent HLA-matching requirement in both sources raises an important possibility for patients in need of urgent transplantation to treat any hematological disease. Selection of the best alternative donor is a difficult task that will depend on donor criteria, center experience, patient disease conditions, and risk, among others. Most comparisons available in scientific publications between both graft sources are obtained from retrospective analysis in wide time windows and a heterogeneous number of patients, types of disease, disease stages, previous treatments, graft source, conditioning regimen, graft vs. host disease (GVHD) approach, and evaluable endpoints. There is also an evident impact of the economic traits since low-income countries must consider less expensive treatments to satisfy the needs of the patients in the most effective possible path. Therefore, haploidentical transplantation could be an appealing option, even though it has not been completely established if any chronic treatment derived from the procedure could become a higher cost. In Colombia, there is a huge experience in UCB transplantation especially in units of pediatric transplantation where benign indications are more common than in adults. Due to the availability of a public UCB bank and HLA high-resolution typing in Colombia, there is a wider inventory of cord blood donors. Unfortunately, we do not have an unrelated bone marrow donor registry, so UCB is an important source along with haploidentical transplantation to consider in decision-making. This minireview focuses on comparing the main issues associated with the use of both HSCP sources and provides tools for physicians who face the difficult decision between these alternative donor sources.

Challenges in Chronic Myeloid Leukemia Management in South America

PURPOSE OF REVIEW

Chronic myeloid leukemia (CML) management in developing countries has improved in the last years, but the availability of therapeutic resources, monitoring, reimbursement, and financial issues may be a challenge and interfere with the best practices and results of CML treatment. This review points out the main challenges in CML management in South America.

RECENT FINDINGS

In this review, we describe the access to tyrosine kinase inhibitors and monitoring in different countries of South America. We also address the ongoing discontinuation trials, the progress, and limitations of hematopoietic stem cell transplantation in the last years. There are still many challenges for achieving the best outcomes for CML patients in South America. The continuous efforts to provide continuous education, access to tyrosine kinase inhibitors, and monitoring, providing reference centers for CML management and hematopoietic stem cell transplantation may improve patients' outcomes.

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.

The challenge of long-term follow-up of survivors of childhood acute leukemia after hematopoietic stem cell transplantation in resource-limited countries: A single-center report from Brazil

With the number of long-term HSCT survivors steadily increasing, attention needs to be focused on the late complications and quality of life. We therefore analyzed the outcome of 101 pediatric patients (<18 years old at the time of HSCT) transplanted for acute leukemia between 1981 and 2015 at Complexo Hospital de Clínicas, Federal University of Paraná, Brazil, and who survived at least two years after HSCT. The median follow-up was 5.9 years (2.0-29.0); median age at follow-up was 17.5 years (2.98-39.0). The 5-year cumulative incidence of relapse was 27.5% (95% CI 18.6%-36.4%). Two-year cumulative incidence of chronic GVHD was 21.8% (95% CI 13.7%-29.8%). Of the 101 patients, 72 patients (71.3%) presented with late effects. Those surviving longer after HSCT experienced more complications. Patients who received TBI-based regimen developed more late effects (P = .013) and more endocrinological complications (P = .024). Endocrinological complications were the most common late sequelae found in this study. For childhood survivors, quality of life was not influenced by age (at HSCT or at last visit), time from HSCT, gender, donor, or GVHD. For survivors that no longer were children, only age at last visit impacted financial domain measures, irrespective of gender, donor, or GVHD. The current study confirms the high burden late complications after pediatric HSCT have on the survivors and underlines the importance of extended follow-up.

Latent Tuberculosis in Hematopoietic Stem Cell Transplantation: Diagnostic and Therapeutic Strategies to Prevent Disease Activation in an Endemic Population

Latent tuberculosis infection (LTBI) affects one-fourth of the world´s population. Hematopoietic stem cell transplantation (HSCT) recipients are at an elevated risk of developing active tuberculosis infection (ATBI). In this retrospective study of donors and HSCT recipients who underwent transplantation between February 2000 and June 2018, our aim was to determine the prevalence of LTBI and ATBI and to describe diagnostic and therapeutic strategies in an HSCT population in an endemic region. The cohort of 409 participants included 125 allogeneic HSCT (allo-HSCT) recipients, 165 autologous HSCT (auto-HSCT) recipients, and 119 HSCT donors. Patients were evaluated pre-HSCT with tuberculin skin test and thoracic imaging. LTBI was diagnosed in 26.2% of the cohort. Cases represented 20% of the auto-HSCT population, 20% of the allo-HSCT population, and 41.2% of the donor population. Pre-HSCT evaluation to rule out ATBI was performed in 62.6% of the cohort; all results were negative. Isoniazid was administered to 73.3% of those with LTBI. Within subgroups, 91.7% of HSCT recipients and 51% of donors received treatment. The median duration of therapy pre-HSCT was 70 days in recipients and 48 days in donors. The incidence of post-HSCT ATBI was 0 at 1-year follow-up. The incidence of LTBI in our population was higher than expected and still might have been underestimated owing to diagnostic test limitations. The absence of incident ATBI suggests that recipients, as opposed to donors, must receive LTBI treatment. Prevention of infectious complications in the HSCT population should be prioritized to improve clinical outcomes. Prospective data from collaborative working groups is needed to determine the best diagnostic and therapeutic approaches in this vulnerable patient population.

Importance of Nongovernmental Organizations for the Establishment of a Successful Hematopoietic Stem-Cell Transplantation Program in a Developing Country

Purpose

In low- and middle-income countries with limited resources, the success of a hematopoietic stem-cell transplantation (HSCT) program relies directly on its affordability while obtaining similar outcomes to developed regions. The objective of this study was to describe the experience of a tertiary/referral center in Mexico City performing HSCT with the subsidy of a nongovernmental organization (NGO).

Patients and Methods

We performed a retrospective analysis including 146 patients who underwent HSCT at the National Institutes of Health Sciences and Nutrition Salvador Zubiran and were subsidized by the NGO Unidos.

Results

Seventy-five patients (51%) and 71 patients (49%) underwent autologous and allogeneic HSCT, respectively. The median age was 30 years, 56% did not obtain a bachelor’s degree, 79% had a low socioeconomic level, and 75% were unemployed. None had any health coverage. According to the real patient out-of-pocket expense, the subsidy by Unidos corresponded to 88% and 72% in autologous and allogeneic HSCT, respectively.

Conclusion

Our results highlight that undergoing an HSCT was feasible for vulnerable patients because of the subsidy of medications and chemotherapy by Unidos. Therefore, creating NGOs in developing countries is important to provide complex medical procedures, such as HSCT, at limited-resource centers to underserved populations while obtaining good outcomes.