Oral hypomethylating agents: beyond convenience in MDS

Clinical activity, pharmacokinetics, and pharmacodynamics of oral hypomethylating agents for myelodysplastic syndromes/neoplasms and acute myeloid leukemia: A multidisciplinary review

OBJECTIVE

To review the pharmacokinetic (PK)-pharmacodynamic (PD) profiles, disease setting, dosing, and safety of oral and parenteral hypomethylating agents (HMAs) for the treatment of myelodysplastic syndromes/neoplasms (MDS) and acute myeloid leukemia (AML), and to provide a multidisciplinary perspective on treatment selection and educational needs relating to HMA use.

DATA SOURCES

Clinical and real-world data for parenteral decitabine and azacitidine and two oral HMAs: decitabine-cedazuridine (DEC-C) for MDS and azacitidine (CC-486) for AML maintenance therapy.

DATA SUMMARY

Differences in the PK-PD profiles of oral and parenteral HMA formulations have implications for their potential toxicities and planned use. Oral DEC-C (decitabine 35 mg and cedazuridine 100 mg) has demonstrated equivalent systemic area under the concentration-time curve (AUC) exposure to a 5-day regimen of intravenous (IV) decitabine 20 mg/m2 and showed no significant difference in PD. The AUC equivalence of oral DEC-C and IV decitabine means that these regimens can be treated interchangeably (but must not be substituted within a cycle). Oral azacitidine has a distinct PK-PD profile versus IV or subcutaneous azacitidine, and the formulations are not bioequivalent or interchangeable owing to differences in plasma time-course kinetics and exposures. Clinical trials are ongoing to evaluate oral HMA combinations and novel oral HMAs, such as NTX-301 and ASTX030.

CONCLUSIONS

Treatment with oral HMAs has the potential to improve quality of life, treatment adherence, and disease outcomes versus parenteral HMAs. Better education of multidisciplinary teams on the factors affecting HMA treatment selection may help to improve treatment outcomes in patients with MDS or AML.

Oral decitabine-cedazuridine versus intravenous decitabine for myelodysplastic syndromes and chronic myelomonocytic leukaemia (ASCERTAIN): a registrational, randomised, crossover, pharmacokinetics, phase 3 study

BACKGROUND

The DNA methyltransferase inhibitors azacitidine and decitabine for individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia are available in parenteral form. Oral therapy with similar exposure for these diseases would offer potential treatment benefits. We aimed to compare the safety and pharmacokinetics of oral decitabine plus the cytidine deaminase inhibitor cedazuridine versus intravenous decitabine.

METHODS

We did a registrational, multicentre, open-label, crossover, phase 3 trial of individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia and individuals with acute myeloid leukaemia, enrolled as separate cohorts; results for only participants with myelodysplastic syndromes or chronic myelomonocytic leukaemia are reported here. In 37 academic and community-based clinics in Canada and the USA, we enrolled individuals aged 18 years or older who were candidates to receive intravenous decitabine, with Eastern Cooperative Oncology Group performance status 0 or 1 and a life expectancy of at least 3 months. Participants were randomly assigned (1:1) to receive 5 days of oral decitabine-cedazuridine (one tablet once daily containing 35 mg decitabine and 100 mg cedazuridine as a fixed-dose combination) or intravenous decitabine (20 mg/m2 per day by continuous 1-h intravenous infusion) in a 28-day treatment cycle, followed by 5 days of the other formulation in the next treatment cycle. Thereafter, all participants received oral decitabine-cedazuridine from the third cycle on until treatment discontinuation. The primary endpoint was total decitabine exposure over 5 days with oral decitabine-cedazuridine versus intravenous decitabine for cycles 1 and 2, measured as area under the curve in participants who received the full treatment dose in cycles 1 and 2 and had decitabine daily AUC0-24 for both oral decitabine-cedazuridine and intravenous decitabine (ie, paired cycles). On completion of the study, all patients were rolled over to a maintenance study. This study is registered with ClinicalTrials.gov, NCT03306264.

FINDINGS

Between Feb 8, 2018, and June 7, 2021, 173 individuals were screened, 138 (80%) participants were randomly assigned to a treatment sequence, and 133 (96%) participants (87 [65%] men and 46 [35%] women; 121 [91%] White, four [3%] Black or African-American, three [2%] Asian, and five [4%] not reported) received treatment. Median follow-up was 966 days (IQR 917-1050). Primary endpoint of total exposure of oral decitabine-cedazuridine versus intravenous decitabine was 98·93% (90% CI 92·66-105·60), indicating equivalent pharmacokinetic exposure on the basis of area under the curve. The safety profiles of oral decitabine-cedazuridine and intravenous decitabine were similar. The most frequent adverse events of grade 3 or worse were thrombocytopenia (81 [61%] of 133 participants), neutropenia (76 [57%] participants), and anaemia (67 [50%] participants). The incidence of serious adverse events in cycles 1-2 was 31% (40 of 130 participants) with oral decitabine-cedazuridine and 18% (24 of 132 participants) with intravenous decitabine. There were five treatment-related deaths; two deemed related to oral therapy (sepsis and pneumonia) and three to intravenous treatment (septic shock [n=2] and pneumonia [n=1]).

INTERPRETATION

Oral decitabine-cedazuridine was pharmacologically and pharmacodynamically equivalent to intravenous decitabine. The results support use of oral decitabine-cedazuridine as a safe and effective alternative to intravenous decitabine for treatment of individuals with myelodysplastic syndromes or chronic myelomonocytic leukaemia.

FUNDING

Astex Pharmaceuticals.

Treatment patterns, resource utilization and clinical outcomes in patients with higher risk myelodysplastic syndromes (MDS) in United States community practices

Management of higher-risk myelodysplastic syndromes (HR-MDS) is challenging in the real world. We studied 200 patients with HR-MDS within a large US community hospital network. We describe the clinical presentation, patient-related factors, prognostic characteristics, treatment patterns, clinical outcomes and resource utilization. Patients with HR-MDS, treated in our community setting, were elderly (median age 76 years) with a high comorbidity burden. First-line therapy was hypomethylating agent (HMA) monotherapy (20%), lenalidomide (2%), and venetoclax (2%), while the rest were treated with supportive care. Sixty-one percent of the 200, were subsequently hospitalized within 6 months of initial diagnosis. Overall survival was 11.8 months. Curative transplantation was infrequent, HMA-based therapy was underutilized, responses were not durable, most patients became transfusion-dependent or transformed to AML, and resource utilization was substantial and was highly correlated with total in-hospital days. There is a clear unmet need for tolerable treatments that can produce durable remissions in this population.

Maintenance therapy for AML after allogeneic HCT

Allogeneic hematopoietic cell transplant (allo-HCT) for eligible patients with acute myeloid leukemia (AML) in first complete remission is a central treatment paradigm to achieve durable remission. However, disease relapse after allo-HCT remains a significant concern and generally portends a poor prognosis. There is significant interest regarding the role for maintenance therapy after allo-HCT for patients with high risk of relapse, regardless of the presence of measurable residual disease. While there are currently no therapies approved for maintenance therapy for AML after allo-HCT, there are a number of ongoing investigations examining the role of maintenance therapies that include targeted agents against FLT3-ITD or IDH mutations, hypomethylating agents, immunomodulatory therapies and cellular therapies. In this review, we examine the current landscape and future strategies for maintenance therapy for AML after allo-HCT.