Decitabine treatment in 311 patients with acute myeloid leukemia: outcome and impact of TP53 mutations - a registry based analysis

Unmet Horizons: Assessing the Challenges in the Treatment of TP53-Mutated Acute Myeloid Leukemia

Acute myeloid leukemia (AML) remains a challenging hematologic malignancy. The presence of TP53 mutations in AML poses a therapeutic challenge, considering that standard treatments face significant setbacks in achieving meaningful responses. There is a pressing need for the development of innovative treatment modalities to overcome resistance to conventional treatments attributable to the unique biology of TP53-mutated (TP53mut) AML. This review underscores the role of TP53 mutations in AML, examines the current landscape of treatment options, and highlights novel therapeutic approaches, including targeted therapies, combination regimens, and emerging immunotherapies, as well as agents being explored in preclinical studies according to their potential to address the unique hurdles posed by TP53mut AML.

Entospletinib with decitabine in acute myeloid leukemia with mutant TP53 or complex karyotype: A phase 2 substudy of the Beat AML Master Trial

BACKGROUND

Patients with acute myeloid leukemia (AML) who have tumor protein p53 (TP53) mutations or a complex karyotype have a poor prognosis, and hypomethylating agents are often used. The authors evaluated the efficacy of entospletinib, an oral inhibitor of spleen tyrosine kinase, combined with decitabine in this patient population.

METHODS

This was a multicenter, open-label, phase 2 substudy of the Beat AML Master Trial (ClinicalTrials.gov identifier NCT03013998) using a Simon two-stage design. Eligible patients aged 60 years or older who had newly diagnosed AML with mutations in TP53 with or without a complex karyotype (cohort A; n = 45) or had a complex karyotype without TP53 mutation (cohort B; n = 13) received entospletinib 400 mg twice daily with decitabine 20 mg/m2 on days 1-10 every 28 days for up to three induction cycles, followed by up to 11 consolidation cycles, in which decitabine was reduced to days 1-5. Entospletinib maintenance was given for up to 2 years. The primary end point was complete remission (CR) and CR with hematologic improvement by up to six cycles of therapy.

RESULTS

The composite CR rates for cohorts A and B were 13.3% (95% confidence interval, 5.1%-26.8%) and 30.8% (95% confidence interval, 9.1%-61.4%), respectively. The median duration of response was 7.6 and 8.2 months, respectively, and the median overall survival was 6.5 and 11.5 months, respectively. The study was stopped because the futility boundary was crossed in both cohorts.

CONCLUSIONS

The combination of entospletinib and decitabine demonstrated activity and was acceptably tolerated in this patient population; however, the CR rates were low, and overall survival was short. Novel treatment strategies for older patients with TP53 mutations and complex karyotype remain an urgent need.

TP53 in AML and MDS: The new (old) kid on the block

MDS and AML are clonal hematopoietic stem cell disorders of increasing incidence, having a variable prognosis based, among others, on co-occurring molecular abnormalities. TP53 mutations are frequently detected in these myeloid neoplasms and portend a poor prognosis with known therapeutic resistance. This article provides a timely review of the complexity of TP53 alterations, providing updates in diagnosis and prognosis based on new 2022 International Consensus Classification (ICC) and World Health Organization (WHO) guidelines. The article addresses optimal testing strategies and reviews current and arising therapeutic approaches. While the treatment landscape for this molecular subgroup is under active development, further exploration is needed to optimize the care of this group of patients with unmet needs.

TP53 signal pathway confers potential therapy target in acute myeloid leukemia

TP53 mutation is a frequent tumor suppressor mutation and a critical prognostic indicator across studies in many malignant tumors including hematologic malignancies. However, the role of TP53 and its correlative pathway in acute myeloid leukemia (AML) is enigmatic, which may provide possible emerging strategies with the potential to improve outcomes in AML. Accordingly, we focus not only on the TP53 mutation but also on the underlying mechanisms of the mutated TP53 signal pathway. While it is now generally accepted that TP53 mutations are widely associated with a dismal prognosis, resistance to chemotherapy, and high incidence of relapse and refractory AML. Hereby, the current therapeutics targeting TP53 mutant AML are summarized in this review. This will address emerging TP53-based therapeutic approaches, facilizing the TP53-targeted treatment options.

The Clinical Value of Decitabine Monotherapy in Patients with Acute Myeloid Leukemia

Decitabine (5-aza-2′-deoxycytidine) is a hypomethylating agent used in the treatment of acute myeloid leukemia (AML). Decitabine inhibits DNA methyltransferases, causing DNA hypomethylation, and leading amongst others to re-expression of silenced tumor suppressor genes. Decitabine is indicated for the treatment of adult patients with newly diagnosed de novo or secondary AML who are not eligible for standard induction chemotherapy. The initial authorization in 2012 was based on the results of the open-label, randomized, multicenter phase 3 DACO-016 trial, and supported by data from the supportive phase 2 open-label DACO-017 trial. Compared with standard care, decitabine significantly improved overall survival, event-free survival, progression-free survival, and response rate. Decitabine was generally well tolerated, offering a valuable treatment option in patients with AML irrespective of age, especially for patients achieving a complete response. Several observational “real-life” studies confirmed these results. In contrast to standard chemotherapy, the presence of adverse-risk karyotypes or TP53 mutations does not negatively impact sensitivity to hypomethylating therapy albeit with lower durability. Data suggest a potential positive effect of decitabine in patients with monosomal karyotype-positive AML. For the time being, decitabine is an appropriate option as monotherapy for patients with AML who are unfit to receive more intensive combination therapies, but emerging data suggest that decitabine-based doublet or triplet combinations may be future treatment options for patients with AML.

Management of Acute Myeloid Leukemia: Current Treatment Options and Future Perspectives

Treatment of acute myeloid leukemia (AML) has improved in recent years and several new therapeutic options have been approved. Most of them include mutation-specific approaches (e.g., gilteritinib for AML patients with activating FLT3 mutations), or are restricted to such defined AML subgroups, such as AML-MRC (AML with myeloid-related changes) or therapy-related AML (CPX-351). With this review, we aim to present a comprehensive overview of current AML therapy according to the evolved spectrum of recently approved treatment strategies. We address several aspects of combined epigenetic therapy with the BCL-2 inhibitor venetoclax and provide insight into mechanisms of resistance towards venetoclax-based regimens, and how primary or secondary resistance might be circumvented. Furthermore, a detailed overview on the current status of AML immunotherapy, describing promising concepts, is provided. This review focuses on clinically important aspects of current and future concepts of AML treatment, but will also present the molecular background of distinct targeted therapies, to understand the development and challenges of clinical trials ongoing in AML patients.