withdrawn

Acute myeloid leukemia(AML) is a clonal hematological malignancy. 50%-90% adult AML patients can achieve complete remission(CR) after standard induction chemotherapy,but 10%-25% patients cannot achieve CR, which is called 'primary refractory disease'.Most of patients who achieved CR will relapse during the next 3 years, and the prognosis is poor.So refractory and relapse diseases are still the hotspot of clinical research.Immunologic escape is one of the mechanisms for tumor cells to survive from chemotherapy. Studies have shown that PD1 and PDL1 levels are upregulated in AML patients, the same phenomenon was observed after the treatment of demethylating agents such as azacytidine. Combination of PD1 blockades with azacytidine may improve the efficacy of the treatment.

In this phase 1/2 study, 20 patients will be enrolled and treated with azacytidine and tislelizumab regimen. The primary endpoint is composite complete remission rate.Toxicities of treatment need to be observed. And relationship between PDL1 expression on AML cells and efficacy will be studied. Treatments include azacytidine 75mg/m2/d, subcutaneous injection,day1-7, every 28 days for three cycles tislelizumab 200mg,day 8,every three weeks, for 4 doses.

Inclusion Criteria:

• diagnosis of AML according to FAB or WHO criteria
• refractory or morphological relapsed AML
• age over 18 years old
• ECOG PS 0-2
• written informed consent

Exclusion Criteria:

• acute promyelocyte leukemia
• solitary extramedullary relapsed disease
• other hematological diseases
• antecedent stem cell transplantation
• AML with BCR_ABL positive
• acute panmyelosis with myelofibrosis or sarcoma
• with other active organ malignancy(needing treatment)
• active heart diseases
• unfit for enrollment after investigator's evaluation