Camrelizumab for Preemptive Treatment of Molecular Recurrence after Allogeneic Hematopoietic Stem Cell Transplantation in Core-Binding Factor Acute Myeloid Leukemia: Two Case Reports

This paper reports two patients with core-binding factor AML (CBF-AML) who experienced molecular recurrence following allogeneic hematopoietic stem cell transplantation (allo-HSCT). They were given preemptive treatment with camrelizumab, an inhibitor of programmed cell death protein 1 (PD-1). In case 1, a 45-year-old male AML patient with persistent CBFβ-MYH11 fusion transcripts received allo-HSCT after complete remission (CR). After transplantation, CBFβ-MYH11 fusion transcript remained persistently positive even after treatment with the hypomethylating agent decitabine. Camrelizumab was administered eight months post-transplantation. After 3 cycles administered at two-week intervals, the CBFβ-MYH11 transcripts became negative. Only mild liver insufficiency and telangiectasia were observed. In case 2, a 20-year-old male AML patient with the AML1-ETO fusion gene experienced molecular recurrence post allo-HSCT, even after treatment with decitabine. Camrelizumab was then administered 1 year after transplantation. After 2 cycles, AML1-ETO transcripts gradually became negative. However, severe immune-related liver injury occurred. Liver function eventually recovered with treatment. In conclusion, PD-1 inhibitors may be an effective strategy for CBF-AML patients with late stage molecular recurrence after allo-HSCT and should be explored further.