Impact of posttransplant cyclophosphamide on the outcome of patients undergoing unrelated single-unit umbilical cord blood transplantation for pediatric acute leukemia.

BACKGROUND: Umbilical cord blood transplantation (UCBT) from unrelated donors is one of the successful treatments for acute leukemia in childhood. The most frequent side effect of UCBT is peri-engraftment syndrome (PES), which is directly associated with the greater prevalence of acute and chronic graft-versus-host-disease (aGvHD and cGvHD). In haploidentical stem cell transplantation, posttransplant cyclophosphamide (PTCY) has been demonstrated to be an effective method against GvHD. However, the effects of PTCY as a GvHD prophylactic in UCBT had not been investigated. This study aimed to evaluate the effects of PTCY on the outcomes of UCBT for pediatric acute leukemia. METHODS: This retrospective study included 52 children with acute leukemia who underwent unrelated single-unit UCBT after myeloablative conditioning regimens. The results from the PTCY and non-PTCY groups were compared. RESULTS: The incidence of transplantation-related mortality in non-PTCY and PTCY were 5% and 10% (p = 0.525), respectively. The incidence of relapse in non-PTCY and PTCY were 5% and 23% (p = 0.095), respectively. Second complete remission status (CR2) was an independent risk factor for relapse-free survival (hazard ratio = 9.782, p = 0.001). The odds ratio for sepsis or bacteremia incidence was significantly greater in the PTCY group (9.524, p = 0.017). PTCY group had increased rates of cytomegalovirus activity and fungal infection. The incidence of PES, aGvHD, cGvHD, and hemorrhagic cystitis in the PTCY group was lower than that in the non-PTCY group, although it was not significantly different. Additionally, higher doses of PTCY (29 mg/kg and 40 mg/kg) were associated with lower incidences of aGvHD and severe GvHD (65% and 29%, respectively) than lower doses (93% and 57%, respectively). Engraftment time and graft failure incidence were similar across groups. CONCLUSION: The results support the safety and efficiency of PTCY as part of PES controlling and GvHD prophylaxis in single-unit UCBT for children with acute leukemia. A PTCY dosage of 29 mg/kg to 40 mg/kg appears to be more effective in GvHD prophylaxis for UCBT patients.

Chidamide as maintenance after chemotherapy or hematopoietic stem cell transplantation in 27 children with T-cell lymphoblastic leukemia: A real-world prospective study.

Background: The long-term overall survival of children with T-cell acute lymphoblastic leukemia (T-ALL) is limited to approximately 80-85% because of a high incidence of relapse after achieving remission with intensive chemotherapy and hematopoietic stem cell transplantation (HSCT). Novel treatment strategies inducing long-term remission are needed to improve the outcome. Histone deacetylase inhibitors (HDACis) have been reported to be effective in a series of T-ALL cases. Preclinical studies suggested that T-ALL cells are sensitive to Chidamide, which is a selective HDACi. Methods: This preliminary clinical study evaluated the efficacy and safety of Chidamide in combination with chemotherapy or post-HSCT for children with T-ALL at a dose of 0.5 mg/kg weight of patient twice per week for at least 6 months. Results: In total, 27 children with a mean age of 7.88 years were included. The high-risk proportion was 66.7%. After a median follow-up period of 37.8 months (9.5-67.9 months), the overall survival and event-free survival in the patients treated with Chidamide were 94.1 and 95.2%, respectively. All patients except two maintained persistent remission with <0.01% blast cells in minimal residual disease. Conclusion: The combination therapy with Chidamide in a case series of T-ALL shows the promising clinical efficacy and good safety in children. Clinical trial registration: https://www.chictr.org.cn/, identifier ChiCTR2000030357.

[Preliminary Study of Chidamide Combined with Hematopoietic Stem Cell Transplantation in the Treatment of Childhood Acute T-Lymphoblastic Leukemia].

OBJECTIVE: To investigate the efficacy and safety of combination chidamide and hematopoietic stem cell transplantation (HSCT) in the treatment of childhood acute T lymphoblastic leukemia (T-ALL). METHODS: Seven children with acute T lymphoblastic leukemia received hematopoietic stem cell transplantation in SUN Yat-Sen Memorial Hospital of SUN Yat-Sen University were selected. 7 cases of T-ALL were divided into 2 groups: HSCT plus chidamide-treated group (4 cases) and traditional HSCT-treated group (3 cases) as control. The incidence of GVHD and other related complications, as well as implantation, recurrence and survival were compared between the two groups, and the side effects of chidamide were observed. All the patients were follow-up until January 2019. RESULTS: All the 7 patients were alive and, there was no difference in the incidence of acute GVHD between the HSCT plus chidamides treated group and the traditional HSCT-treated group. The implantation rate of HSCT was 100%, and there were no recurrence occurred. During the application of chidamide, 3 cases showed adverse reactions, of which 2 cases had adverse reactions of grade 3 or higher, and 2 cases were hematological adverse reactions (neutropenia, thrombocytopenia), other adverse reactions were non-hematologic adverse reactions (transaminase elevation, fatigue, nausea, vomiting), there were no serious adverse reactions occurred. In the HSCT plus chidamide-treated group, 2 cases were found that mature lymphocytes were not expressed by tumors, during examing for minimal redidaul disease (MRD). Compared with the immunophenotype and TCR rearrangement at first diagnosis, the results did not support the source of residual T-ALL tumor cells. During the review of MRD, it was found that the abnormal T cells showed an increasing trend, indicating that chidamide might induce leukemia cell differentiation through some pathways. CONCLUSION: Hematopoietic stem cell transplantation is still an effective method to cure children's T-ALL. In some cases, abnormal T-cell nonclonal amplification occurs during the application of chidamide, and the children with T-ALL can tolerable adverse reactions of chidamide.