Efficacy and Safety of Azacytidine Combined with Low-Dose Lenalidomide in Preemptive Treatment of Post Allo-SCT Acute Myeloid Leukemia Patients with Detectable Minimal Residual Disease

Objective To evaluate the efficacy and safety of azacytidine combined with low-dose lenalidomide in preemptive treatment of acute myeloid leukemia (AML) patients with detectable minimal residual disease (MRD) after allogeneic hematopoietic stem cell transplantation. Methods Patients diagnosed with acute myeloid leukemia who had undergone allogeneic hematopoietic stem cell transplantation and had detectable MRD measured by flow cytometry, PCR or next generation sequencing were treated with azacytidine and low-dose lenalidomide (AZA 50-75mg/m², day 1-5; LEN 5-10mg/m², d8-28; 28-42 days for cycle, adjusted according to patient tolerance). If graft-versus-host disease occurs during treatment, the use of lenalidomide was delayed as appropriate. In patients without graft-versus-host disease (GVHD) whose MRD was still detectable after azacytidine and low-dose lenalidomide treatment, donor lymphocyte infusion was further added to enhance efficacy. Results a total of 15 AML patients with post-transplant detectable MRD received azacytidine and lenalidomide treatment and 7 patients received additional donor lymphocyte infusion. After a median follow-up of 441 days, MRD became undetectable after receiving azacytidine and lenalidomide and remain negative in 10 patients. In 3 patients whose MRD was once undetectable, MRD was positive again during treatment, of which 2 were lost to follow-up and 1 was recently received DLI. Hematological relapse was observed in 2 patients. Grade 3-4 neutropenia was observed in 8 patients, none of which develop febrile neutropenia; grade 3-4 thrombocytopenia was observed in 3 patients; Grade 3 aminotransferase elevation occurred in 2 patients. Four patients developed chronic GVHD after treatment, with a NIH score of 1-2, and none of the patients developed acute GVHD. Conclusion Azacytidine combined with low-dose lenalidomide is a promising method for the preemptive treatment of post-transplant AML patients with detectable MRD. Its side effects are controllable and dose not increase the risk of graft-versus-host disease.

No relevant conflicts of interest to declare.