Standard intensive chemotherapy is less effective and far more toxic than attenuated induction and post-induction regimen in elderly patients with acute myeloid leukemia

Dose intensity for induction in acute myeloid leukemia: what, when, and for whom?

Intensive chemotherapy has been the backbone of the treatment of acute myeloid leukemia (AML) for decades. However, an increase in novel targeted agents, which has been brought about in part by a deeper understanding of the genetic makeup of AML, has led to remission-inducing regimens that do not require traditional cytotoxic agents. Combinations of a hypomethylating agent (HMA) and venetoclax have doubled the chance of remission for patients considered unfit for induction chemotherapy who would have traditionally been offered singleagent HMA. In fact, this regimen may rival the complete remission rate achieved with induction chemotherapy for certain populations such as the very elderly and those with secondary AML, but equivalency has yet to be established. Further advances include the addition of gemtuzumab ozogamicin and FLT3 inhibitors to induction chemotherapy, which improves survival for patients with core-binding factor and FLT3-mutated AML, respectively. Still, much work is needed to improve the outcomes of the highest-risk subgroups: frail patients and those with high-risk cytogenetics and/or TP53 mutations. Promisingly, the landscape of AML therapy is shifting dramatically and no longer is intensity, when feasible, always the best answer for AML.

Efficacy and Safety of Metronomic Chemotherapy Versus Palliative Hydroxyurea in Unfit Acute Myeloid Leukemia Patients: A Multicenter, Open-Label Randomized Controlled Trial

Background:

Management of unfit AML patients is a therapeutic challenge. Most hematologists tend to avoid aggressive treatment leaving patients with a choice of best supportive care. We hypothesized that metronomic chemotherapy could be an alternative treatment for unfit AML patients.

Methods:

A multi-center randomized controlled trial was conducted in seven university-affiliated hospitals in Thailand. Unfit AML patients were recruited and followed up from December 2014 to December 2017. Patients were randomly assigned to receive either metronomic chemotherapy or palliative hydroxyurea. Overall survival rates were compared using Cox’s proportional hazard survival analysis.

Results:

A total of 81 eligible patients were randomly allocated and included for ITT analysis. The OS rate was higher in group receiving metronomic chemotherapy than in group receiving palliative treatment at 6 and 12 months with borderline significance (6 months HR 0.60; 95%CI 0.36, 1.02; p-value 0.060; 12 months: HR 0.66; 95%CI 0.41, 1.08; p-value 0.097).

Conclusion:

Metronomic chemotherapy could prolong survival time of unfit AML patients, especially in the first 12 months after diagnosis without increasing treatment-associated adverse events.

The histone deacetylase inhibitor Romidepsin induces as a cascade of differential gene expression and altered histone H3K9 marks in myeloid leukaemia cells

Myelodysplastic syndromes (MDS) are a heterogeneous, clonal haematopoietic disorder, with ~1/3 of patients progressing to acute myeloid leukaemia (AML). Many elderly MDS patients do not tolerate intensive therapeutic regimens, and therefore have an unmet need for better tolerated therapies.

Epigenetics is important in the pathogenesis of MDS/AML with DNA methylation, and histone acetylation the most widely studied modifications. Epigenetic therapeutic agents have targeted the reversible nature of these modifications with some clinical success. The aim of this study was to characterise the molecular consequences of treatment of MDS and AML cells with the histone deacetylase inhibitor (HDACi) Romidepsin.

Romidepsin as a single agent induced cell death with an increasing dose and time profile associated with increased acetylation of histone H3 lysine 9 (H3K9) and decreased HDAC activity. Gene expression profiling, qPCR, network and pathway analysis recognised that oxidation-reduction was involved in response to Romidepsin. ROS was implicated as being involved post-treatment with the involvement of TSPO and MPO.

Genomic analysis uncoupled the differences in protein-DNA interactions and gene regulation. The spatial and temporal transcriptional differences associated with acetylated, mono- and tri-methylated H3K9, representative of two activation and a repression mark respectively, were identified. Bioinformatic analysis uncovered positional enrichment and transcriptional differences between these marks; a degree of overlap with increased/decreased gene expression that correlates to increased/decreased histone modification. Overall, this study has unveiled a number of underlying mechanisms of the HDACi Romidepsin that could identify potential drug combinations for use in the clinic.

A prospective, observational study of added medium-dose cytosine arabinoside versus As2O3 for elderly patients with acute promyelocytic leukemia

This open-label, prospective, observational study aimed to evaluate disease-free survival (DFS), overall survival (OS), PML-RARα polymerase chain reaction (PCR) monitoring and safety in elderly patients with de novo acute promyelocytic leukemia (APL) who were treated with either arsenic trioxide (As2O3) or medium-dose cytosine arabinoside (MiDAC) as frontline consolidation regimens. A total of 167 patients (age≥65 years old) received all-trans retinoic acid + daunorubicin as induction therapy. Of these patients, 22 died before attaining complete remission; the remaining 145 subjects received MiDAC- or As2O3-based consolidation therapy. As2O3 was superior to MiDAC for improving DFS and OS. This benefit appeared to result from the longer 5-year DFS (92.0 vs. 69.1%, P<0.01) and OS (94.5 vs. 79.7%, P<0.05) of As2O3 compared to MiDAC. PCR monitoring demonstrated that As2O3 promoted a lower positive rate than MiDAC (21.7 vs. 4.5%, P<0.05), but this treatment had no advantage for maintaining a low positive rate in the high-risk group. The most common life-threatening adverse drug effects in patients with MiDAC were platelet counts<25×10(9)/L (85.7%), leukocyte counts<1.0×10(9)/L (81.4%) and severe infection (84.3%). In contrast, the As2O3 regimen rarely caused leukocyte counts<1.0×10(9)/L (22.7%, P<0.01), platelet counts<25×10(9)/L (37.3%, P<0.01) or severe infection (21.3%, P<0.01). These data confirm that MiDAC should not be added during the initial consolidation of patients with APL because this treatment is far less effective, particularly in patients with a low-risk profile, and far more toxic than As2O3.