[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.