Will next-generation agents deliver on the promise of epigenetic hypomethylation therapy?

Therapeutic Applications of Azanucleoside Analogs as DNA Demethylating Agents

Azanucleosides, such as 5-azacytidine and decitabine, are DNA demethylating agents used in the treatment of acute myeloid leukemia and myelodysplastic syndromes. Researchers continue to explore their utility in the treatment of other hematologic and solid tumors. Based on the capacity of the compounds to inhibit DNA methyltransferase enzymes and the important role of DNA methylation in health and disease, it is essential to understand the molecular changes that azanucleosides induce and how these changes may improve treatment outcomes in subsets of patients. This review summarizes the molecular and therapeutic actions of azanucleosides and discusses recent clinical trials of these compounds as single agents or in combination therapy for the treatment of cancer and related conditions.

New FDA oncology small molecule drugs approvals in 2020: Mechanism of action and clinical applications

In 2020, fifty-three new drugs, including forty small-molecules (thirty-six new chemical entities and four new diagnostic agents) and thirteen biologic drugs were approved by the U.S. Food and Drug Administration (FDA). This year, small-molecules continue to play a role in innovative treatments representing around 75% of all drugs accepted by FDA. The dominant therapeutic area was oncology, accounting for twenty-three new approvals, including thirteen new chemical entities, four new diagnostic agents, and thirteen biologic drugs. Recognizing the importance of small-molecules on cancer treatment, this review aims to provide an overview regarding the clinical applications and mechanism of action of the thirteen new small-molecules (excluding new diagnostic agents) approved by FDA in 2020.

Myelodysplastic Syndromes: How to Recognize Risk and Avoid Acute Myeloid Leukemia Transformation

PURPOSE OF REVIEW

To understand how myelodysplastic syndromes (MDS) transform to AML and to describe how transformation can be predicted and prevented.

RECENT FINDINGS

Recent genomic analyses have shown that MDS progression to AML is associated with clonal expansion and clonal evolution. Mutation profiles of MDS change during progression and new mutations in signaling genes and transcription factors emerge. AML transformation can be predicted by several parameters including International Prognostic Scoring System IPSS risk category and transfusion requirements. The prognostic relevance of the acquisition of some gene mutations (i.e., IDH1 and 2, CBL, FT3, RAS, NPM1, TP53, and ASXL1) has to be prospectively validated. The most effective preventive therapy for AML transformation is allogeneic stem cell transplantation. Hypomethylating agents have been associated with prolonged time to AML transformation even in patients who did not achieve an objective response. The recent progress in the understanding of the molecular events leading to transformation and the event of new effective therapies open new avenues for a better prediction and prevention of AML transformation in patients with MDS.

An oral fixed-dose combination of decitabine and cedazuridine in myelodysplastic syndromes: a multicentre, open-label, dose-escalation, phase 1 study

BACKGROUND

Decitabine, a DNA methyltransferase 1 inhibitor or DNA hypomethylating compound, is not readily orally bioavailable because of rapid clearance by cytidine deaminase (CDA) in the gut and liver. This dose-escalation study, guided by pharmacokinetic and pharmacodynamic observations, evaluated whether simultaneous oral administration with the novel CDA inhibitor cedazuridine increases decitabine bioavailability for the treatment of myelodysplastic syndromes.

METHODS

In this phase 1 study, we enrolled patients aged 18 years or older with myelodysplastic syndromes or chronic myelomonocytic leukaemia. Eligible patients were assigned to cohorts to receive escalating oral doses of decitabine and cedazuridine. The starting dose was decitabine 20 mg and cedazuridine 40 mg. Treatment cycles lasted 28 days, with 5 days of drug administration. In cycle 1, each patient received a cohort-defined dose of oral decitabine on day -3, a 1-h intravenous infusion of decitabine 20 mg/m² on day 1, and cohort-defined doses of oral decitabine plus cedazuridine on days 2-5. In cycles 2 and beyond, the oral decitabine and cedazuridine were given on days 1-5. The dose of cedazuridine was escalated first and decitabine was escalated once CDA inhibition by cedazuridine approached the maximum effect. The drug dose was escalated if mean decitabine area under the curve (AUC) of the oral drug was less than 90% of that for intravenous decitabine in the cohort and if no dose-limiting toxicity was observed. Dose-limiting toxicity was defined as a grade 3 or greater non-haematologic toxicity or grade 4 haematologic toxicity lasting more than 14 days and unrelated to the underlying disease. Once the decitabine AUC target range set as the primary endpoint, and established with intravenous decitabine, was reached at a dose deemed to be safe, the cohort that most closely approximated intravenous decitabine exposure was expanded to 18 evaluable patients. The primary objectives were to assess the safety of decitabine plus cedazuridine, and to determine the dose of each drug needed to achieve a mean AUC for decitabine exposure similar to that for intravenous decitabine exposure. This study is registered with ClinicalTrials.gov, number NCT02103478.

FINDINGS

Between Oct 28, 2014, and Nov 13, 2015, we enrolled 44 eligible patients (of 75 screened) with previously treated or newly diagnosed myelodysplastic syndromes or chronic myelomonocytic leukaemia; 43 of the enrolled patients were evaluable. Participants were treated in five cohorts: cohorts 1-4 included six evaluable patients each; cohort 5 included 19 patients in a 13-patient expansion. Dose-dependent increases in decitabine AUC and peak plasma concentration occurred with each cohort dose escalation. There was no evident increase in toxicity compared with that reported for intravenous decitabine. Decitabine 30 mg and 40 mg plus cedazuridine 100 mg produced mean day-5 decitabine AUCs (146 ng × h/mL for decitabine 30 mg, and 221 ng × h/mL for decitabine 40 mg) closest to the mean intravenous-decitabine AUC (164 ng × h/mL). The most common grade 3 or more adverse events were thrombocytopenia (18 [41%] of 44 patients), neutropenia (13 [30%]), anaemia (11 [25%]), leukopenia (seven [16%]), febrile neutropenia (seven [16%]), and pneumonia (seven [16%]). Four (9%) patients died because of adverse events, none of which was considered drug related, and three (7%) patients died more than 30 days after discontinuing treatment because of progressive disease (two [5%]) and respiratory failure (one [2%]).

INTERPRETATION

Oral decitabine plus cedazuridine emulated the pharmacokinetics of intravenous decitabine, with a similar safety profile and dose-dependent demethylation. Clinical responses were similar to intravenous decitabine treatment for 5 days. Further study of decitabine plus cedazuridine as an alternative to parenteral therapy or in combination with other new oral agents for myeloid disorders is warranted.

FUNDING

Astex Pharmaceuticals, Inc.

Incorporating novel approaches in the management of MDS beyond conventional hypomethylating agents

In the last decade, the treatment of higher-risk myelodysplastic syndromes (MDS) has revolved around the azanucleosides, azacitidine and decitabine, which at lower doses are postulated to work predominantly via their effects on inhibition of DNA methyltransferases and consequent DNA hypomethylation. For patients who relapse after, or do not respond to, hypomethylating agent therapy, the outcome is dismal, and new agents and approaches that have the potential to alter the natural history of these diseases are desperately needed. Allogeneic stem cell transplant is the only known potentially curative approach in MDS, but its applicability has been limited by the advanced age of patients and attendant comorbidities. There is now an increasing array of new agents under clinical investigation in MDS that aim to exploit our expanding understanding of molecular pathways that are important in the pathogenesis of MDS. This review focuses on a critical appraisal of novel agents being evaluated in higher-risk MDS that go beyond the conventional hypomethylating agent therapies approved by the US Food and Drug Administration.

Dose, schedule, safety, and efficacy of guadecitabine in relapsed or refractory acute myeloid leukemia

BACKGROUND

Outcomes for patients with relapsed or refractory acute myeloid leukemia (AML) are poor. Guadecitabine, a next‐generation hypomethylating agent, could be useful in treating such patients.

METHODS

In this multicenter, open‐label, phase 2 dose‐expansion study, AML patients from 10 North American medical centers were first randomized (1:1) to receive subcutaneous guadecitabine at 60 or 90 mg/m² on 5 consecutive days in each 28‐day cycle (5‐day regimen). Subsequently, another cohort was treated for 10 days with 60 mg/m² (10‐day regimen).

RESULTS

Between June 15, 2012, and August 19, 2013, 108 patients with previously treated AML consented to enroll in the study, and 103 of these patients were treated; 5 patients did not receive the study treatment. A total of 103 patients were included in the safety and efficacy analyses (24 and 26 patients who were randomly assigned to 60 and 90 mg/m²/d, respectively [5‐day regimen] and 53 patients who were assigned to 60 mg/m²/d [10‐day regimen]). The 90 mg/m² dose showed no benefit in clinical outcomes in comparison with 60 mg/m² in the randomized cohort. Composite complete response (CRc) and complete response (CR) rates were higher with the 10‐day regimen versus the 5‐day regimen (CRc, 30.2% vs 16.0%; P = .1061; CR, 18.9% vs 8%; P = .15). Adverse events (grade ≥ 3) were mainly hematologic, with a higher incidence on the 10‐day regimen. Early all‐cause mortality was low and similar between regimens. Twenty patients (8 on the 5‐day regimen and 12 on the 10‐day regimen) were bridged to hematopoietic cell transplantation.

CONCLUSIONS

Guadecitabine has promising clinical activity and an acceptable safety profile and thus warrants further development in this population. Cancer 2018;124:325‐34. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Outcomes for patients with relapsed or refractory acute myeloid leukemia are poor. Guadecitabine, a next‐generation hypomethylating agent, has promising clinical activity and an acceptable safety profile and warrants further development in this population.

See also pages 242‐4.

Combining Type I Interferons and 5-Aza-2'-Deoxycitidine to Improve Anti-Tumor Response against Melanoma

Resistance to IFN-I-induced antineoplastic effects has been reported in many tumors and arises, in part, from epigenetic silencing of IFN-stimulated genes by DNA methylation. We hypothesized that restoration of IFN-stimulated genes by co-administration of the demethylating drug 5-aza-2'-deoxycitidine (decitabine [DAC]) may enhance the susceptibility to IFN-I-mediated antitumoral effects in melanoma. We show that combined administration of IFN-I and DAC significantly inhibits the growth of murine and human melanoma cells, both in vitro and in vivo. Compared with controls, DAC/IFN-I-treated melanoma cells exhibited reduced cell growth, augmented apoptosis, and diminished migration. Moreover, IFN-I and DAC synergized to suppress the growth of three-dimensional human melanoma spheroids, altering tumor architecture. These direct antitumor effects correlated with induction of the IFN-stimulated gene Mx1. In vivo, DAC/IFN-I significantly reduced melanoma growth via stimulation of adaptive immunity, promoting tumor-infiltrating CD8⁺ T cells while inhibiting the homing of immunosuppressive CD11b⁺ myeloid cells and regulatory T cells. Accordingly, exposure of human melanoma cells to DAC/IFN-I induced the recruitment of immune cells toward the tumor in a Matrigel (Corning Life Sciences, Kennebunkport, ME)-based microfluidic device. Our findings underscore a beneficial effect of DAC plus IFN-I combined treatment against melanoma through both direct and immune-mediated anti-tumor effects.