RecruitingPhase 2Drug trialMitoxantrone Hydrochloride Liposome Injection, Cytarabine Combined With Venetoclax in the Treatment of R/R AMLThe goal of this study is to evaluate the efficacy and safety of a combination regimen of mitoxantrone hydrochloride liposome injection, cytarabine and venetoclax (MAV) in the treatment of relapsed or refractory (R/R) AML. It will also tentatively explore the correlation between different biological characteristics and therapeutic efficacy. The main questions it aims to answer are:Dose the combination regimen of MAV enhanced the composite complete remission in R/R AML? Participants will receive laboratory tests of bone marrow and blood specimens at regular times after MAV treatment.