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Modulation of Stem Cell Differentiation in Individuals With High Risk Clonal Haematopoiesis

A Multi-centre, Double-blind, Placebo-controlled Randomised Phase II Trial to Evaluate the Effect of Low Dose Decitabine and Tetrahydrouridine in Individuals With High-risk Clonal Haematopoiesis

Status
Not yet recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07435636
Acronym
MOSAIC
Enrollment
80
Registered
2026-02-27
Start date
2026-04-13
Completion date
2030-10-01
Last updated
2026-02-27

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

CCUS Clonal Cytopenia of Undetermined Significance, Clonal Cytopenia of Uncertain Significance, Clonal Hematopoiesis

Keywords

MOSAIC, CH, Modulation of stem cell differentiation, CCUS, persistent cytopenia, clonal hematopoiesis, clonal haematopoiesis, Clonal Cytopenia of Uncertain Significance

Brief summary

Clonal hematopoiesis (CH) is characterized by the overproduction of blood cells derived from a single hematopoietic stem and progenitor cell (HSPC) harboring certain somatic mutations. It is linked to serious outcomes, including cardiovascular disease, myeloid neoplasm (MN), and increased mortality. Clonal Cytopenia of Uncertain Significance (CCUS) is a CH subtype characterized by associated persistent cytopenia. It affects approximately 10 % of people over 70 and is the most advanced precursor state with the highest risk of progressing to MN. There is an unmet need to determine whether modifying CH can prevent adverse outcomes. Current blood cancer therapies are too toxic for precursor conditions like CH. MOSAIC is a randomized double-blind placebo-controlled trial that will test a novel low-dose oral epigenetic therapy-decitabine with tetrahydrouridine (Dec+THU) in CCUS. It has shown targeted, non-cytotoxic reversal of common CH mutations in preclinical and early-phase studies. The goal is to develop a safe and effective therapy in CCUS that restores normal blood cell production and prevents progression.

Interventions

After randomization, participants will receive oral combination capsules containing decitabine (Dec) (2.5 mg) and tetrahydrouridine (THU) (125 mg) minitablets, or matched placebo. Trial medication will be dispensed on Day 1 of each cycle and taken once weekly (Days 1, 8, 15, 22) for 24 weeks. Dosing of Dec+THU will follow weight-based dosing at 0.2mg/kg and 10mg/kg respectively. This is a phase II, multicenter, double-blind, placebo-controlled randomized trial

Placebo capsules will be administered on the same schedule and dosing frequency to the active drug

Sponsors

Clinical Hub for Interventional Research (CHOIR)
Lead SponsorOTHER_GOV
Medical Research Future Fund
CollaboratorOTHER
Australian National University
CollaboratorOTHER
University of Auckland, New Zealand
CollaboratorOTHER
Treebough Therapies
CollaboratorINDUSTRY
The University of New South Wales
CollaboratorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender
ALL
Age
60 Years to 85 Years
Healthy volunteers
No

Inclusion criteria

1. Age ≥ 60 and ≤ 85 years old 2. Clonal Cytopenia of Uncertain Significance (CCUS), defined by all of the following: a. Persistent cytopenia, present on at least two occasions, at least four months apart, with no other cause identified: i. Hemoglobin (Hb) \< 120 g/L in people born female, and \< 130 g/L in people born male ii. Platelet count \< 150 x 109/L iii. Absolute Neutrophil Count (ANC) \< 1.8 x109/L b. Clonal hematopoiesis (CH) driver mutation confirmed by custom gene panel mutation analysis c. absence of features diagnostic for defined myeloid neoplasm (MN) on bone marrow examination 3. CH driver mutation variant allele fraction (VAF) of ≥ 10% 4. For participants living with HIV: 1. Receiving and adherent to suppressive antiretroviral therapy for at least 12 months 2. CD4+T cell count ≥ 0.35 x 109/L 3. HIV viral load \< 50 copies/mL 6\. Performance status by Eastern Cooperative Oncology Group (ECOG) Criteria of 0 or 1 7. For participants who are of childbearing potential, or whose partners are of childbearing potential: 1. Agreement to use at least two highly effective (per Clinical Trial Facilitation Group) contraceptive methods throughout the course of the trial, and for 6 months following the last dose of trial drug 2. Refrain from donating eggs or sperm during the same period 3. Confirmation of a negative serum pregnancy test at screening and at the beginning of each treatment cycle visit (for female participants of childbearing potential) 8. Provision of signed written informed consent document prior to any trial-related assessments or procedures being carried out

Exclusion criteria

1. ANC \< 0.5 x109/L 2. Serum AST (Aspartate transaminase) or ALT (Alanine aminotransaminase) \> 3 times of upper limit of normal 3. Calculated or measured creatinine clearance ≤ 50 mL/min 4. Significant active cardiac disease within the previous 6 months, including: 1. New York Heart Association (NYHA) class III or IV congestive heart failure 2. Unstable angina or angina requiring surgical or medical intervention 3. Myocardial infarction 4. New or unstable cardiac arrhythmia. Stable or controlled arrhythmias are permitted 5. Active systemic infections: 1. Infection with ongoing signs/symptoms related to the infection without improvement despite appropriate anti-infectives 2. Active Hepatitis B infection (HBV) (defined as HBsAg positive, or HBcAb positive and measurable HBV DNA; participants who are HBcAb positive must have HBV DNA assayed during screening) 3. Active Hepatitis C Virus (HCV) will be ineligible if there is clinical hepatic dysfunction or other systemic manifestations of HCV disease, or if the hepatic eligibility parameters above are not met. Consideration should be given to curative HCV therapy prior to enrolment in consultation with HCV clinician 6. Any history of hematological or solid malignancy in previous the 5 years unless the participant has been free of disease for ≥ 36 months. However, participants with the following history/concurrent conditions are not excluded: 1. Basal or squamous cell carcinoma of the skin 2. Carcinoma in situ of the cervix 3. Carcinoma in situ of the breast 4. Incidental histologic finding of prostate cancer (T1a or T1b using the tumor, nodes, metastasis \[TNM\] clinical staging system) 7. Known hypersensitivity to trial drugs or their constituents 8. Currently enrolled in the treatment phase of an interventional investigational trial. 9. Pregnant or breast-feeding individuals 10. Any condition not already outlined above which, in the opinion of the Principal Investigator, would place the participant at risk if they participated or would jeopardize adherence, follow up, or confound the ability to interpret trial data

Design outcomes

Primary

MeasureTime frameDescription
Change in variant allele fraction (VAF) in peripheral blood mononuclear cells (PBMC) at the completion of 24 weeks of treatment.End of Treatment (Week 24)Change in variant allele fraction (VAF) in peripheral blood mononuclear cells (PBMC), at the completion of 24 weeks of treatment, will be used to compare the evolution of clonal cytopenia of undetermined significance (CCUS) in individuals with CCUS and associated clinically significant cytopenia receiving Dec+THU compared with those receiving placebo, by intention-to-treat analysis. VAF will be assessed by capture sequencing using the Auckland Myeloid Gene Panel V4 (AMGPV4)

Secondary

MeasureTime frameDescription
Number and proportion of participants: a) experiencing Grade 3, 4 and 5 adverse events (AE) b) discontinuing treatment due to AEs or Serious Adverse Events (SAEs) c) living with HIV maintaining HIV Viral Load (VL) suppressionEnd of Treatment (Week 24)The safety profile of Dec+THU treatment will be evaluated at the end of 24 weeks of treatment. Each cycle is 28 days.
Number and proportion of participants completing planned 24 weeks of treatment.End of Treatment (Week 24)The feasibility of Dec+THU treatment will be evaluated by number and proportion of participants completing planned 24 weeks of treatment
Number and proportion of participants with cytopenia responseEnd of Treatment (Week 24) and Follow Up 1 (Week 48)Participant cytopenia response will be assessed and measured according to the 2018 International Working Group (IWG) criteria with comparison between the Dec+THU treatment group and the placebo group
Duration of cytopenia responseEnd of Treatment (Week 24) and Follow Up Visit 1 (Week 48)Duration of cytopenia response will be assessed and measured according to the 2018 International Working Group (IWG) criteria with comparison between the Dec+THU treatment group and the placebo group
Changes in VAF in subgroups defined by cytopenias and baseline mutationsBaseline (Week 0), at the start of Cycle 4 Day 1 (Week 12) (each cycle is 28 days), End of Treatment (Week 24), Follow Up Visit 1 (Week 48) and Follow Up Visit 2 (Week 96)VAF will be measured to compare changes in VAF in subgroups defined by baseline cytopenias and baseline mutations. DNA extracted from the peripheral blood will be sequenced after NGS library preparation and target-enrichment with a custom capture panel (Agilent Sure Select). Next Generation Sequencing (NGS) will be performed and the number of variant reads at a given position will be used to calculate the VAF. VAF will be a direct measure of the fraction of cells carrying the variant in the sample used for DNA extraction.
Changes in peripheral blood VAFBaseline (Week 0), at the start of Cycle 4 Day 1 (Week 12) (each cycle is 28 days), End of Treatment (Week 24), Follow Up Visit 1 (Week 48), Follow Up Visit 2 (Week 96)Peripheral blood VAF will be measured at timepoints to compare changes in VAF between the Dec+THU treatment group and placebo group DNA extracted from the peripheral blood will be sequenced after NGS library preparation and target-enrichment with a custom capture panel (Agilent Sure Select). Next Generation Sequencing (NGS) will be performed and the number of variant reads at a given position will be used to calculate the VAF. VAF will be a direct measure of the fraction of cells carrying the variant in the sample used for DNA extraction.
Changes in the levels of inflammatory cytokines between treatment groups in peripheral blood and bone marrow.Baseline (Week 0), at the start of Cycle 4 Day 1 (Week 12) (each cycle is 24 weeks), End of Treatment (Week 24), Follow Up Visit 1 (Week 48), Follow Up Visit 2 (Week 96)Inflammatory cytokine profile changes will be compared between the Dec+THU treatment group and placebo group in peripheral blood and bone marrow. Serum and plasma will be extracted from participant bone marrow and peripheral blood samples for quantifying inflammatory cytokines levels to compare inflammatory cytokines profile changes between the treatment groups.
Changes in bone marrow (BM) VAFScreening, End of Treatment (Week 24)This comparison will be made by measuring bone marrow VAF to determine if there are any changes between treatments groups at screening and end of treatment. DNA extracted from the bone marrow will be sequenced after NGS library preparation and target-enrichment with a custom capture panel (Agilent Sure Select). Next Generation Sequencing (NGS) will be performed and the number of variant reads at a given position will be used to calculate the VAF. VAF will be a direct measure of the fraction of cells carrying the variant in the sample used for DNA extraction.

Countries

Australia

Contacts

CONTACTProfessor Mark Polizzotto
mosaic.jcsmr@anu.edu.au+61000000000

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 28, 2026