Based on the current treatment with retinoic acid (ATRA) and arsenic (As), most patients with APL achieved long-term survival. There are few patients relapsed and became refractory to the RA and As treatment. In our pre-clinical study, we found that targeting histone deacetylase inhibitor 3 (HDAC3)degraded PML-RARa oncoprotein and induced differentiation and apoptosis of RA and As resistant APL in vitro and in vivo. In this study, we evaluate the efficacy and feasibility of combination therapy for HDAC3 inhibitor and venetoclax in patients with refractory APL.

For patients with newly-diagnosed acute promyelocytic leukemia (APL), the combination therapy retinoic acid (ATRA) combined with arsenic (As) is the mainstay upfront treatment. Most patients enjoy long-term survival with or without chemotherapy. Even though with such good prognosis, there are still some patients relapsed and eventually became refractory to RA and As treatment. In our pre-clinical study, we demonstrate that targeting histone deacetylase inhibitor 3 (HDAC3) could degrade PML-RARa oncoprotein and induce differentiation and apoptosis of RA and As resistant APL in vitro and in vivo. In this multi-center prospective study, we evaluate the efficacy and feasibility of combination therapy for HDAC3 inhibitor (chidamide) and venetoclax in patients with refractory APL.

Inclusion Criteria:

• Patients with PML-RARα+ APL
• Patients in non-remission status after treatment of RA combined with As
• Patients with life expectance >=3 months
• Inform consent provided

Exclusion Criteria:

• Patients with incontrollable infection
• Patients with life-expectancy less than 2 months
• Patients with abnormal liver (>3XN) and renal function (>3XN）

Individual participant data is available only based on request to study director or principle investigator