Quality of Response in Acute Myeloid Leukemia: The Role of Minimal Residual Disease

Autologous stem cell transplantation (ASCT) for acute myeloid leukemia in patients in first complete remission after one versus two induction courses: A study from the ALWP of the EBMT

BACKGROUND

Achieving complete remission (CR) is the main goal in AML treatment and a prerequisite for successful autologous stem cell transplantation (ACT).

METHODS

Comparing results of peripheral blood ACT in patients with AML in CR1 attained following 1 versus 2 chemotherapy courses transplanted in 2000-2019.

RESULTS

Patients 1532 (84%) with one and 293 (16%) patients with two induction chemotherapies courses (a total of 1825 patients) were included in the study. Follow-up was 7.9 (95% CI: 7.4-8.4) and 7.7 (95% CI: 7.0-8.6) years (p = 0.8). Time from diagnosis to ACT was 4.7 (range, 3.9-5.8) versus 5.7 (range, 4.7-7.1) months (p < 0.001), respectively. Leukemia free survival (LFS) and overall survival (OS) at 5 years were inferior for patients achieving CR1 with 2 versus 1 course of chemotherapy: 26.6% versus 41.7% (HR = 1.42 [95% CI: 1.22-1.66], p < 0.001) and 36.2% versus 53.3%, (HR = 1.48 [95% CI: 1.25-1.75], p < 0.001), and 5-year relapse incidence (RI) was higher: 67.2% versus 52.3%, (HR = 1.46 [95% CI: 1.25-1.72], p < 0.001). Five-year non-relapse mortality (NRM) was 6.2% versus 6.0% for patients with 2 versus 1 chemotherapy courses, and did not differ significantly (HR = 1.31 [95% CI: 0.81-2.10], p = 0.27).

CONCLUSIONS

LFS and OS were inferior and relapse rate was higher in AML patients who received two inductions chemotherapy courses to reach CR1 before being autografted. AML patients who required 2 induction courses to achieve remission, may be offered allogeneic transplantation rather than an autologous one in an attempt to reduce their high RI and improve outcomes.

Measurable residual disease by flow cytometry in acute myeloid leukemia is prognostic, independent of genomic profiling

Measurable residual disease (MRD) assessment provides a potent indicator of the efficacy of anti-leukemic therapy. It is unknown, however, whether integrating MRD with molecular profiling better identifies patients at risk of relapse. To investigate the clinical relevance of MRD in relation to a molecular-based prognostic schema, we measured MRD by flow cytometry in 189 AML patients enrolled in ECOG-ACRIN E1900 trial (NCT00049517) in morphologic complete remission (CR) (28.8 % of the original cohort) representing 44.4 % of CR patients. MRD positivity was defined as ≥ 0.1 % of leukemic bone marrow cells. Risk classification was based on standard cytogenetics, fluorescence-in-situ-hybridization, somatic gene analysis, and sparse whole genome sequencing for copy number ascertainment. At 84.6 months median follow-up of patients still alive at the time of analysis (range 47.0-120 months), multivariate analysis demonstrated that MRD status at CR (p = 0.001) and integrated molecular risk (p = 0.0004) independently predicted overall survival (OS). Among risk classes, MRD status significantly affected OS only in the favorable risk group (p = 0.002). Expression of CD25 (α-chain of the interleukin-2 receptor) by leukemic myeloblasts at diagnosis negatively affected OS independent of post-treatment MRD levels. These data suggest that integrating MRD with genetic profiling and pre-treatment CD25 expression may improve prognostication in AML.

Non-T depleted haploidentical stem cell transplantation in AML patients achieving first complete remission after one versus two induction courses: a study from the ALWP/EBMT

There are no data indicating whether the number of induction courses needed to achieve first complete remission (CR1) is of prognostic significance in Haploidentical transplantation (HaploSCT). We compared transplantation outcomes of adults with AML that underwent HaploSCT in CR1, achieved following one or two induction courses. A total of 635 patients were included: 469 (74%) with 1 and 166 (26%) with two induction chemotherapy courses. A total of 429 (91.5%) and 151 (91%) patients had de novo AML and 40 (8.5%) and 15 (9%) had secondary AML (p = 0.84). Engraftment rates were 97.2 and 97.6%. Day 180 incidence of acute GVHD II-IV and III-IV was similar in both induction groups (31.1 and 34.8%, and 10 and 10.6 %), as was 2-4 year total and extensive chronic GVHD (33.7 and 36.5 %, and 12.2 and 12.1%), respectively. Two-year relapse incidence (RI) was higher while leukemia-free survival (LFS), overall survival (OS) and GVHD-free, relapse-free survival (GRFS) were inferior for patients achieving CR1 with 2 vs 1 course and were 29.1% vs 15.1%, 88 (p = 0.001), 56.2% vs 66.9% (p = 0.03), 58.8% vs 72.2% (p = 0.044) and 44% vs 55.6% (p = 0.013), respectively. Non-relapse mortality (NRM) did not differ, 18% vs 14.6% 90 (p = 0.25). These results were confirmed by multivariate analysis.

HDAC8 promotes daunorubicin resistance of human acute myeloid leukemia cells via regulation of IL-6 and IL-8

The chemoresistance is one of the major challenges for acute myeloid leukemia (AML) treatment. We found that the expression of histone deacetylase 8 (HDAC8) was increased in daunorubicin (DNR) resistant AML cells, while targeted inhibition of HDAC8 by its specific siRNA or inhibitor can restore sensitivity of DNR treatment . Further, targeted inhibition of HDAC8 can suppress expression of interleukin 6 (IL-6) and IL-8. While recombinant IL-6 (rIL-6) and rIL-8 can reverse si-HDAC8-resored DNR sensitivity of AML cells. Mechanistical study revealed that HDAC8 increased the expression of p65, one of key components of NF-κB complex, to promote the expression of IL-6 and IL-8. It might be due to that HDAC8 can directly bind with the promoter of p65 to increase its transcription and expression. Collectively, our data suggested that HDAC8 promotes DNR resistance of human AML cells via regulation of IL-6 and IL-8.