The results of ten years’ experience in allogeneic hematopoietic stem cell transplantation at the Russian Children’s Clinical Hospital

Abstract

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a common treatment for a large number of pediatric diseases. Treatment planning is based on a careful selection of patients and donors, taking into account factors contributing to a successful outcome. The aim of our study was to analyze the results of 10 years’ experience in allo-HSCT gained at the Department of Bone Marrow Transplantation of the Russian Children's Clinical Hospital of the N.I. Pirogov Russian National Research Medical University. We retrospectively analyzed 506 patients who had undergone their first allo-HSCTs between January 2010 and December 2020. The study was approved by the Independent Ethics Committee and the Scientific Council of the N.I. Pirogov Russian National Research Medical University of Ministry of Healthcare of the Russian Federation. We included 243 patients who had received allo-HSCT before December 2015 and 263 patients who had received allo-HSCT after January 2016. The gender distribution was 60.1% male (n = 304) and 39.9% female (n = 202). The median age was 7.13 years. Allo-HSCT recipients were divided into two groups: 236 children with non-malignant disease, 270 children with malignant disease. In the malignant group, 89 patients were in first complete remission (CR1), 92 were in second complete remission (CR2), and 20 were in third complete remission (CR3) and beyond; 63 patients had active disease (AD); 6 patients received no prior treatment. Two hundred and twenty patients underwent allo-HSCT from a fully matched family donor (MFD), 172 from a matched unrelated donor (MUD), 33 from a mismatched unrelated donor (MMUD) and 81 from a haploidentical (mismatched) family donor (MMFD). Two hundred and eighty-eight patients received bone marrow as a stem cell source, 208 received peripheral blood stem cells; 10 transplants were performed using umbilical cord blood stem cells. The 5-year overall survival (OS) in the entire cohort was 71.34 %. The 5-year OS in the patients who had undergone allo-HSCT between 2016 and 2020 was higher (p = 0.0014). After 2015, the rates of primary graft failure, the incidence of grade III–IV acute “graft-versus-host” disease (GVHD), and recurrence rates were significantly lower. No difference in the incidence of grade III–IV acute GVHD (p = 0.494) and OS rates (p = 0.138) was seen between different sources of hematopoietic stem cells in the patients who received an HLA-compatible transplant (MFD, MUD). Chronic GVHD was significantly dependent on the severity of acute GVHD and donor type. The 3-year OS rate for the patients in CR1, CR2, ≥ CR3, and AD was 84.4 %, 60.5 %, 56.8 %, and 46 % (p = 0.0034), respectively. The relapse rate of the patients in any remission was lower than of those in active disease (p = 0.015). The transplantation-related mortality in the first 100 days after allo-HSCT was 6.92% (n = 35). The patients who had undergone allo-HSCT after 2015 had lower rates of primary graft failure, a decreased incidence of severe GVHD, improved OS and relapse-free survival rates. The frequency of grade III–IV acute GVHD strongly correlated with HLA compatibility. Chronic GVHD was less frequent in MFD recipients. The risk of chronic GVHD increased with the severity of acute GVHD. The HLA mismatch between a donor and a recipient was associated with a decrease in OS. With each subsequent remission, the OS rate decreased. The risk of recurrence was higher in the patients transplanted in active disease. The results of this study can be used in clinical practice to plan therapy, choose an optimal donor, and develop strategies for the prevention and treatment of complications.