Improved CLAG Regimen Followed By Haploidentical Hematopoietic Stem Cell Transplantation Treating Patients With Relapse Or Refractory Acute Myeloid Leukemia

Background: The prognosis of relapse or refractory acute myeloid leukemia(rrAML)is very poor and the treatment is challenging,due to the common failure to achieve complete remission(CR)and high relapse rate.Objective: To determine the efficacy and safety of the improved CLAG regimen followed by haploidentical hematopoietic stem cell transplantation(haplo-HSCT)treating rrAML patients.Methods: Analyzed the clinical features of the 20 patients with rrAML.Compared the differences in CR rate,the median time of neutrophil counts < 0.5×10^9/L and platelet counts < 20×10^9/L after chemotherapy,treatment related mortality(TRM),2-years relapse-free survival(RFS)and overall survival(OS)between the 20 patients treating with improved CLAG regimen and the 40 patients previously treating with conventional CLAG regimen.Then evaluated the value of haplo-HSCT in rrAML.Results: 1)The clinical features: The number of male and female was equal.The median age at diagnosis was 44.5 years old.The most frequent subgroup of bone marrow morphology was M5b(45%),followed by M2a(40%).2)The efficacy of chemotherapy: The patients treating with improved CLAG regimen had similar CR rate(65% vs.67.5%,P>0.05),shorter median time of neutrophil counts<0.5×10^9/L(11days vs.18 days,P<0.01)and platelet counts<20×10^9/L(10 days vs.17 days,P<0.01)after chemotherapy,lower TRM rate(5% vs.17.5%,P<0.01)and higher 2-years RFS(69.2% vs.39.4%,P=0.023)and OS(69.9% vs.41.9%,P=0.047)compared with treating with conventional CLAG regimen.3)The superiority of haplo-HSCT: Five patients underwent haplo-HSCT after achieving CR and none of them relapsed,whereas 8 patients continued to receive chemotherapy as consolidation therapy and the relapse rate was 62.5%.The median time of RFS and OS was longer(795 days vs.405 days,P=0.012;869 days vs.483days;P=0.005)in patients who underwent haplo-HSCT compared with patients who only received chemotherapy.Conclusion: The improved CLAG regimen followed by haplo-HSCT treating rrAML patients is efficient and safe,especially for those with intolerance to intensive chemotherapy.