Combination of Homoharringtonine with Venetoclax and Azacitidine Excerts Better Treatment Response in Relapsed /Refractory Acute Myeloid Leukemia

Overexpression of Bcl-2 is known to be an important factor for drug resistance in relapsed /refractory acute myeloid leukemia (R/R-AML). Combination of Bcl-2 inhibitor venetoclax with hypomethylating agents (HMA) has shown promising killing effect in elder patients with newly diagnosed AML, also worked in R/R-AML but with low rate of complete response (CR). High expression of Bcl-XL and/or Mcl-1 is the main reason for resistance to venetoclax. As an inhibitor of both Bcl-XL and Mcl-1, homoharringtonine (HHT) has presented a synegetic effect with venetoclax in inhibition of Mcl-1 and killing of lymphama. In this study, we analyzed the treatment response and safety of combination of HHT (1mg/m² d1-7) with venetoclax (400mg d1-14) and azacitidine (75mg/m² d1-7) (HVA) in R/R-AML. From 6, 2019 to 5, 2020, in Nanfang Hopsital, 22 patients with RR-AML were treated with HVA (HVA group), with a median age of 39(16-62) years, previous chemotherapy of 3(1-7) cycles. 15 (68.2%) relapsed within one year after allogenetic hematopoietic stem cell transplantation (allo-HSCT) and 12 (54.5%) previously exposed to HMA treatment. Meanwhile, 7 patients with RR-AML were treated with venetoclax combined with HMA (control group), with a median of 42(31-74) years, previous chemotherapy of 3(1-6) cycles. 2 (28.6%) relapsed after allo-HSCT and 5 (71.4%) had HMA exposure. In HVA group, totally 11/17(64.7%) patients acquired treatment response, and 7/15(46.7%) obtained CR/CRi, of whom 6 presented minimal residual disease (MRD) negative. While in control group, only 2/7(28.6%) acquired treatment response and 1 obtained CR. Subgroup analysis in HVA group showed allover response rate (ORR) was 9/13(69.2%) and CR rate was 6/11(54.5%) (all with MRD negative) in the patients with allo-HSCT. And in the patients without allo-HSCT ORR was 2/4(50.0%) and CR rate was 1/4. With a median follow-up of 6(1-7) months, one patient was bridged to allo-HSCT, 2 out of 7 patients with CR relapsed. All patients were well tolorated to both treatment regimens, showing as a median neutropenia of 9.5(5-14) days, 5 patients with Febrile neutropenia and 4 with pulmonary infection. In conclusion, combination of HHT with venetoclax and azacitidine (HVA) excerts better treatment response in R/R-AML, especially in those with allo-HSCT, and shows well tolorated. A multi-center prospective clinical trial (NCT04424147) has been initiated.

Key words: HVA regimen, relapsed /refractory acute myeloid leukemia, treatment response, safety