Taiho Oncology Presents Data on All-Oral Regimens Azacitidine and Cedazuridine, and Decitabine and Cedazuridine at the 2025 American Society of Hematology Annual Meeting and Exposition

• Two oral presentations will highlight Phase 2 results from the ASTX030-01 trial of oral azacitidine and cedazuridine in patients with myelodysplastic syndromes, chronic myelomonocytic leukemia or acute myeloid leukemia and Phase 2 results from ASTX727-03 trial of low-dose oral decitabine and cedazuridine in patients with lower-risk myelodysplastic syndromes
• New data from 15 company-sponsored and company-funded externally led studies demonstrate increasing understanding of novel oral regimens in hematology

PRINCETON, N.J., Dec. 8, 2025 /PRNewswire/ -- Taiho Oncology, Inc., a company developing and commercializing novel treatments for hematologic malignancies and solid tumors, today announced new data from the company-sponsored ASTX030-01 and ASTX727-03 studies evaluating all-oral regimens of azacitidine and cedazuridine or decitabine and cedazuridine in patients with myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML) or acute myeloid leukemia (AML). Data from the studies will be shared in two oral presentations at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition, to be held on December 6-9, 2025, in Orlando, Florida. Collectively, new data from 15 company-sponsored and company-funded externally led studies will be presented, demonstrating an increasing commitment to understanding novel oral regimens in hematology.

An oral presentation will highlight results from the Phase 2 ASTX030-01 trial, a multicenter, randomized, open-label, crossover trial comparing the all-oral combination of azacitidine and cedazuridine to subcutaneous azacitidine among patients with MDS, CMML or AML.

A second oral presentation will share findings from the Phase 2 ASTX727-03 trial of low-dose oral decitabine and cedazuridine versus an attenuated course of standard-dose decitabine in patients with lower-risk MDS.

Azacitidine and decitabine belong to a class of antineoplastic agents known as DNA methyltransferase inhibitors (DMTIs). Each is paired with cedazuridine, a cytidine deaminase inhibitor, to help the agent stay active in the body without degrading.

"We are pleased to present positive data suggesting that oral azacitidine and cedazuridine in patients with MDS, CMML and AML, and decitabine and cedazuridine in patients with lower-risk MDS may be comparable in safety and effectiveness to frequently used parenteral therapies for those populations," said Harold Keer, MD, PhD, Chief Medical Officer of Taiho Oncology. "While standard hypomethylating agents are administered via infusion in the clinic, these novel treatments are designed to be taken orally at home, potentially improving flexibility and lowering the treatment burden for patients."

Authors will report results from the ASTX030-01 study of oral azacitidine and cedazuridine versus subcutaneous azacitidine in patients with MDS, CMML or AML: ¹

Investigator Summary of Results

As of the May 2025 data cutoff, 30 patients received treatment, including 22 individuals with MDS, five with CMML, two with AML and one with MDS/myeloproliferative neoplasms (MPN); all were eligible for single-agent azacitidine. The patients were randomly assigned in a 1:1 ratio to receive ongoing cycles of therapy. One group received ASTX030 except during cycle 2, when subcutaneous azacitidine was administered, while the other group received subcutaneous azacitidine in cycle 1 followed by ASTX030 in all subsequent cycles.

As of the data cutoff, ASTX030 Phase 2 results demonstrated the following:

• The primary endpoint was the geometric mean ratio (GMR) of azacitidine total cycle AUC 0–24 exposures after oral ASTX030 over subcutaneous azacitidine, and the result for that endpoint was 0.913 (90% confidence interval [CI]: 0.78, 1.07).
• In patients with MDS (n=22), the complete response (CR) rate was 22.7% and overall response rate was 50%.
• Among patients who were dependent on red blood cell (RBC) transfusions at baseline (n=13), 30.8% achieved independence from RBC transfusions for 56 days or more.

When stratifying by body surface area (BSA), patients with intermediate BSA had a GMR of 0.980 (90% CI: 0.85, 1.13), whereas the subset of patients with a high BSA had a GMR of 0.700 (90% CI: 0.55, 0.89) and further simulations suggested that BSA-adjusted dosing will help ensure the PK exposure of the oral combination approximates that of subcutaneous azacitidine.

Summary of Preliminary Safety and Tolerability

• Adverse events (AEs) were reported in 100% of trial participants, with 83.3% of those AEs classified as grade 3 or higher.
• The most common treatment-emergent adverse events (TEAEs), the majority of which were grade 1 or 2, were nausea (70%), constipation (66.7%) and fatigue (60%).
• The most common TEAEs of grade 3 or higher were thrombocytopenia (43.3%), neutropenia (33.3%) and anemia (30%).
• AEs leading to treatment withdrawal or dose reduction occurred in two (6.7%) and four (13.3%) patients, respectively, and there were 12 (40%) AEs that led to treatment interruption or delay.

Authors will report results from the ASTX727-03 study of low-dose oral decitabine and cedazuridine versus standard-dose decitabine and cedazuridine in patients with lower-risk MDS²

Investigator Summary of Results

As of the October 2024 data cutoff, 81 patients with low-risk or intermediate-1 MDS and either one or more cytopenias or dependence on red blood cell transfusions were treated in the Phase 2 ASTX727-03 study, comparing a low-dose (LD), all-oral regimen of decitabine and cedazuridine with an attenuated course of standard dose (SD) decitabine and cedazuridine (DEC-C). Patients received 10 mg of oral decitabine and 100 mg cedazuridine for five days or 35 mg decitabine and 100 mg cedazuridine for three days. Patients were treated a median of 8.8 months, with patients in the LD arm receiving a median of 10 cycles and those in the SD arm receiving a median of 9 cycles.

As of the data cutoff, ASTX727-03 Phase 2 results demonstrated the following:

• Median overall survival (OS) was 23.9 months in the LD arm versus 26.0 months in the SD arm.
• Median leukemia-free survival (LFS) was 23.8 months in the LD arm versus 25.7 months in the SD arm.
• Hematologic improvement per International Working Group 2006 criteria was achieved in 27.5% LD patients and 26.8% SD patients.
• Among patients dependent on RBC transfusions, 52.4% of LD patients and 37.5% SD patients achieved RBC transfusion independence.
• Pharmacokinetic exposure AUC in the LD arm was approximately half that in the SD arm.

Summary of Preliminary Safety and Tolerability

• Delayed cycles occurred in 72.5% of patients in the LD arm versus 82.9% of those in the SD arm. Dose reductions occurred in 40% of patients in the LD cohort versus 46.3% of patients in the SD group.
• Both treatment regimens caused a decrease in blood counts. Neutropenia was more pronounced in early cycles and was more severe in the SD arm. Blood counts across all lineages remained stable or improved through 12 or more cycles with the LD arm, suggesting a more favorable safety and tolerability profile.
• AEs of grade 3 or higher occurred in 85% of patients in the LD arm and 90.2% of patients in the SD arm. Treatment discontinuation due to AEs occurred in 2.5% of patients in the LD arm versus 17.1% of patients in the SD arm.
• The most commonly reported treatment-emergent AEs were anemia (42.5% LD versus 39% SD), fatigue (32.5% LD versus 43.9% SD) and thrombocytopenia (37.5% LD versus 39% SD).
• 3 deaths occurred in the trial: 2 in the LD arm, both unrelated to study treatment, and 1 in the SD arm due to pseudomonal bacteremia in cycle 1, which was treatment-related.

About Taiho Oncology, Inc.

The mission of Taiho Oncology, Inc. is to improve the lives of patients with cancer, their families and their caregivers. The company specializes in the development and commercialization of orally administered anti-cancer agents for various tumor types. Taiho Oncology has a robust pipeline of small-molecule clinical candidates targeting solid-tumor and hematological malignancies, with additional candidates in pre-clinical development. Taiho Oncology is a subsidiary of Taiho Pharmaceutical Co., Ltd. which is part of Otsuka Holdings Co., Ltd. Taiho Oncology is headquartered in Princeton, New Jersey and oversees its parent company's European and Canadian operations, which are located in Baar, Switzerland and Oakville, Ontario, Canada.

For more information, visit https://www.taihooncology.com/, and follow us on LinkedIn and X.

Taiho Oncology and the Taiho Oncology logo are registered trademarks of Taiho Pharmaceutical Co., Ltd.

Taiho Oncology Contact:

Leigh Labrie

(609) 664-9878

llabrie@taihooncology.com

References

1. Guillermo Garcia-Manero et al. A phase 2 dose confirmation trial of oral ASTX030, a combination of oral azacitidine with cedazuridine among patients with myelodysplastic syndromes, chronic myelomonocytic leukemia, and acute myeloid leukemia
2. Guillermo Garcia-Manero et al. Low-dose oral decitabine and cedazuridine among patients with low-risk myelodysplastic syndromes

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