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3302 A Modified Busulfan/Cyclophosphamide Conditioning Regimen Incorporating Cladribine for Autologous Hematopoietic Stem Cell Transplantation in Acute Leukemia

Program: Oral and Poster Abstracts
Session: 721. Clinical Allogeneic Transplantation: Conditioning Regimens, Engraftment, and Acute Transplant Toxicities: Poster III
Hematology Disease Topics & Pathways:
Leukemia, ALL, AML, Adult, Diseases, Lymphoid Malignancies, Study Population, Myeloid Malignancies, Clinically relevant
Monday, December 7, 2020, 7:00 AM-3:30 PM

Yuanyuan Shi1*, Guixin Zhang1*, Yi He1*, Ming-Zhe Han1, Sizhou Feng, MD1*, Rongli Zhang, MD1* and Erlie Jiang2*

1National Clinical Research Center for Blood Diseases, State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
2State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China

Objective : To investigate the safety and efficacy of a modified busulfan(Bu)/cyclophosphamide(Cy) conditioning regimen incorporating cladribine(CLAD) for autologous hematopoietic stem cell transplantation(auto-HSCT) in acute leukemia(AL).

Methods: We retrospectively evaluated the clinical outcomes of patients with AL who had received auto-HSCT with conditioning incorporating CLAD at the Institute of Hematology and Blood Disease Hospital.

Results: Between September 2016 and April 2020, 32 adult patients with AL were enrolled including 22 males and 10 females with a median age of 32(range, 15 to 57) years. There were 19 patients with acute myeloid leukemia(AML) and 13 with acute lymphoblastic leukemia(ALL). The median courses of chemotherapy before auto-HSCT were 5 courses(range, 3 to 9) and all patients were minimal residual disease(MRD) negative before auto-HSCT. Twelve out of the 19 AML patients received myeloablative conditioning regimens including: Bu 3.2 mg/kg/d*3, Cy 40mg/kg/d*2, CLAD 5mg/m2/d*3, cytarabine(Ara-c) 2g/m2/d*3 or idarubicin 12mg/m2/d*3. The other 7 patients with AML received the similar modified conditioning regimens as above mentioned but CLAD and Ara-c were administered for 5 days while Cy was abandoned for its adverse cardiovascular reactions. All the 13 patients with ALL received conditioning regimens including: Cy 40mg/kg/d*2, CLAD 5mg/m2/d*3, Ara-C 2-3g/m2/d*3, combined with 10Gy total body irradiation or 100mg/m2 melphalan or 40mg/kg etoposide. Most of the patients received peripheral blood stem cells for auto-HSCT except one who received both peripheral blood and bone marrow stem cells. The median amount of infused mononuclear cell and CD34+ stem cell were 8.68×108/kg(range, 2.06 to 20.97) and 2.10×106/kg(range, 1.59 to 10.44), respectively. All the 32 patients achieved neutrophil and platelet engraftment with a median time of 12(range, 9 to 34) days and 19(range, 10 to 113) days, respectively. Five patients suffered from septicemia during neutropenia stage, 2 patients suffered from pulmonary infection, the others suffered from mild to moderate infection or gastrointestinal reaction after conditioning and all were relieved by anti-infection and other supportive treatment. None of the patients died of transplant related complications. From 2 months after auto-HSCT, the maintenance therapy with interleukin-2, interferon or azacitidine was performed for 8 patients with AML, tyrosine kinase inhibitors were performed for 5 patients with Ph-positive ALL. For 8 patients with Ph-negative ALL, the maintenance therapy was vindesine + prednisone ± Cy or 6-mercaptopurine + methotrexate. At a median follow-up of 14(range, 1.5 to 44.5) months, seven patients (4 patients with AML, 3 patients with ALL) relapsed after auto-HSCT at a median time of 6(range, 0.5 to 18.5) months. One patient with AML died due to leukemia relapse at 18 months after auto-HSCT and the remaining 31 patients were all alive including 25 patients with MRD negative and the other 6 patients achieved MRD negative after allogeneic HSCT or chemotherapy. The estimated 2-year survival, relapse, and disease-free survival rates were 92.9%, 31.1% and 68.9%, respectively.

Conclusions: The modified conditioning incorporating CLAD was safe and effective for auto-HSCT in acute leukemia which might be confirmed by more clinical studies.

Disclosures: No relevant conflicts of interest to declare.

*signifies non-member of ASH