Combination of Haploidentical Hematopoietic with Low-Dose ATG, Ptcy and Cord Blood Competitive Transplantation for Hematologic Malignancies

Objective: To evaluate the efficacy and safety of the combination of haploidentical hematopoietic with low-dose ATG, PTCy and cord blood competitive transplantation for hematologic malignancies.

Methods: This study was conducted as a retrospective review of medical records of 31 patients with hematologic malignancies who received a combination of haploidentical hematopoietic with low-dose ATG, PTCy and cord blood competitive transplantation at Fujian medical university union hospital, from November 2016 to April 2019.

Results: Among the 31 patients with hematologic malignancies, the median age was 22 (6-52) years, of which 17 were CR patients and 14 were No CR patients. The conditioning was modified FABuCy+ low-dose ATG (total dose 5mg/kg) based regimen. Cord blood units were selected based on the results of HLA typing and cell doses evaluated before freezing. Units with at least 5/10 matched HLA loci became the candidates. Prophylaxis for graft-versus host disease(GVHD) was by CsA(cyclosporine), MMF (mycophenolate mofetil) plus PTCy(post-transplant cyclophosphamide). The median values of absolute total nucleated cell counts were 123.0 (49.0-258.8) × 10⁷ / kg in The haploidentical grafts and 2.5 (1.1-13.0 × 10⁷ / kg in the cord blood units,respectively. The median Doses of CD34+ cells infused were 70.0 (11.8-297.6) × 10⁵ / kg in the haploidentical grafts and 1.4 (0.1-13.0) × 10⁵ / kg in the cord blood units, respectively. All patients attained complete engraftment , of which 19 were haploidentical engraftment and 12 were cord blood engraftment. The median durations of myeloid engraftment were 14 (12-37) days and 14.5 (10-48) days for Platelets. With a cumulative platelet engraftment incidence of 90.3%. During a median follow-up of 8.5 (1.3-30.7) months, the incidence of grade II-IV acute GVHD at 100-day was 47.5%, grade III-IV acute GVHD was 13.8%, respectally. The incidence of limited chronic GVHD at 1-year was 35.1%, severe chronic GVHD was 14.6 %, respectively. The estimated 1-year OS was 76.1%,DFS was 68.5% ,GRFS was 60.6%, NRM was 18.5% , RM was 6.7% , respectively. The estimated 1-year OS of CR patients and No CR patients were 92.9% and 55.0%(p=0.114), DFS were 83.6% and 51.9%(p=0.053),NRM were 7.1% and 31.2%(p=0.132),relapse were 10.0% and 30.4%(p=0.131), respectively.

Conclusion:The results suggested that the combination of haploidentical hematopoietic with low-dose ATG, PTCy and cord blood competitive transplantation may potentially improve the outcome of HSCT. It offers a transplant alternative for patients with hematologic malignancies who lack matching donors.