A Phase 2a, Randomized, Double-Blind, Placebo-Controlled Dose Comparison and Exploratory Efficacy Study of Orally Administered SAT-3247 in Ambulatory DMD Patients

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Satellos Bioscience Inc.

Participant type

Pediatric, Patients

Age range

0-17 years

Gender

Male

Therapeutic area

Diseases [C] - Nervous System Diseases [C10], Diseases [C] - Musculoskeletal Diseases [C05]

Trial duration

8 Apr 2026 → ongoing

Decision date (initial)

2026-01-22

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

Yes

Funding sources

Satellos Bioscience Inc

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Pharmacokinetic, Dose response, Efficacy

Safety: The primary safety objective is to evaluate the safety and tolerability of SAT-3247 in ambulatory DMD patients.
Efficacy: The primary efficacy objective is to determine SAT-3247 effects on muscle force as determined by dynamometry at 12 weeks

Secondary objectives 8

1. To determine SAT-3247 effects on intramuscular fat fraction in muscle quantitative magnetic resonance (qMR) in vastus lateralis at 12 weeks.
2. To determine SAT-3247 effects on proton muscle transverse relaxation time (T2) in vastus lateralis at 12 weeks
3. To determine SAT-3247 effects on the Regeneration Index in open muscle biopsy of the biceps brachii at 12 weeks
4. To determine population PK of SAT-3247 in ambulatory patients.
5. To determine the potential for improvement in muscle function with treatment of SAT-3247 in ambulatory patients
6. Exploratory objective: to determine SAT-3247 effects on respiratory function at 12 weeks
7. Exploratory objective: to determine SAT-3247 effects on muscle histopathology of the biceps brachii at 12 weeks
8. Exploratory objective: to compare changes in outcomes to natural history

Conditions and MedDRA coding

Duchenne muscular dystrophy

Study design 2 periods

Regulatory references

Scientific advice from competent authorities

Food And Drug Administration, Medicines And Healthcare Products Regulatory Agency

Plan to share IPD

No

IPD plan description

Individual participant data will not be shared, as the sponsor does not plan to make the dataset available outside the study team

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 13

1. Has a definitive diagnosis of DMD based on documented clinical findings and prior genetic testing with a confirmed mutation in the DMD gene
2. Male DMD patients who are ambulatory and aged ≥ 7 to < 10 years at the time of screening
3. Completed two four-stair climb assessments at Visit 1 with a mean of 8 seconds or less (≤1 s variance).
4. Have a time to rise of at least 3 seconds but less than 10 seconds.
5. Healthy, as determined by investigator including medical history, psychiatric history, and no clinically significant findings on physical examination, laboratory tests, and cardiac monitoring.
6. Ability for participant and caregiver to communicate satisfactorily with the investigator and to participate in, and comply with the requirements of, the entire trial including scheduled visits, procedures/assessments, questionnaires, laboratory tests, and study restrictions
7. Participant’s parent(s) or legal guardian(s) have provided written consent to participate after reading the information and consent form, and after having the opportunity to discuss the trial with the investigator or their delegate; participants will be asked to give written or verbal assent according to local requirements.
8. Stable dose of daily systemic glucocorticoids (i.e., prednisolone, deflazacort, or vamorolone) according to the standard of care for ≥ 3 months prior to the Screening Visit and for the duration of the trial. a. Patients who are not receiving glucocorticosteroids are also eligible if stopped ≥ 3 months prior to the Screening Visit.
9. Stable doses of prescription medicines including ACE inhibitors, β-blockers, and diuretics (excluding glucocorticosteroids) and over-the-counter medicines and/or herbal supplements for supportive care ≥ 1 month prior to the Screening Visit and for the duration of the trial.
10. If participant is taking (or has taken within 4 weeks prior to enrollment) herbal remedies and supplements which can impact muscle strength and function (e.g., Co-enzyme Q10, creatine, etc.), these are maintained on a stable regimen for the duration of the trial.
11. Participants that have previously received delandistrogene moxeparvovec (brand name Elevidys) either in a prior clinical trial or in the commercial setting > 18 months prior to screening whose muscle function tests have stabilized or demonstrated decline ≥ 3 months prior to Screening, as determined by investigator and documented in chart notes, will be eligible. a. Enrollment of participants previously treated with gene therapy, whether delandistrogene moxeparvovec or another investigational gene therapy product, will be capped at 25% and stratified between cohorts
12. Participants that have previously received an exon skipper > 6 months prior to Screening whose muscle function tests have stabilized or demonstrated declined ≥ 3 months prior to Screening, as determined by investigator and documented in chart notes, will be eligible.
13. If participating in a physical therapy/strength training regimen, must be stable for ≥ 2 months prior to the Screening Visit and for the duration of the trial.

Exclusion criteria 16

1. Ambulatory patients expected to experience loss of ambulation within ≤ 12 months.
2. Participants maintained on a ten day on/ten day off corticosteroid regimen
3. 11 Ongoing participation in any other therapeutic clinical trial or follow-up study for a therapeutic intervention, prior treatment with an investigational gene therapy product (other than delandistrogene moxeparvovec) < 24 months prior to the Screening Visit, or receipt of a stable dose of an approved exon-skipping therapy or any medication indicated for DMD (other than corticosteroids including vamorolone and givinostat in accordance with exception 11b below) within 6 months prior to the Screening Visit. a. Participants that have received a commercially available gene therapy product (i.e., delandistrogene moxeparvovec) > 18 months prior to screening whose muscle function tests have stabilized or demonstrated decline as determined by investigator and documented in the medical record ≥ 3 months prior to screening will be eligible. b. Participants receiving a stable dose of givinostat (brand name Duvyzat) for at least18 months or longer prior to the Screening Visit will be eligible. a. Participants unable to tolerate givinostat who discontinued treatment are eligible to enroll if date of last dose is ≥ 30 days from Screening date. Givinostat should not be discontinued, if tolerated, in order to meet study entry criteria. c. Use of deflazacort (brand name Emflaza) or vamorolone (brand name Agamree) in jurisdictions where these are investigational as they have not received health authority marketing authorization will not be exclusionary; however, simultaneous participation in a clinical trial of deflazacort or vamorolone will be excluded.
4. Received SAT-3247 in another study.
5. Severe behavioural or cognitive problems that preclude participation in the study, in the opinion of the investigator.
6. Positive test for hepatitis B surface antigen (HBsAg), hepatitis C antibody (HCV) or HIV at Screening Visit.
7. Employee of the Sponsor, the CRO and/or study site or their relatives
8. Presence of acute or chronic illness or history of chronic illness (other than DMD) sufficient to invalidate participation in the trial or make it unnecessarily hazardous in the judgment of the investigator.
9. Prior or ongoing medical condition (e.g., concomitant illness, psychiatric condition, behavioral disorder), medical history, physical findings, ECG findings, or laboratory abnormality that, in the investigator's opinion, could adversely affect the safety of the participant, makes it unlikely that the course of treatment or follow up would be completed, or could impair the assessment of study results.
10. Participants for whom MRI or open muscle biopsy are contraindicated.
11. Surgery (e.g., stomach bypass) or medical condition that might affect absorption of medicines.
12. Have acute gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea, heartburn) or acute infection (such as influenza) or a significant infection or known inflammatory process at Screening.
13. Impaired cardiac function defined as a left ventricular ejection fraction of < 50% on screening cardiac assessments (echocardiogram or MRI) or evidence of symptomatic cardiomyopathy.
14. A forced vital capacity < 60% predicted at the Screening Visit.
15. Presence or history of severe adverse reaction to any excipients (lactose monohydrate, microcrystalline cellulose, colloidal silicon dioxide, copovidone, crospovidone, sodium strearyl fumarate) in the study medication tablets.
16. Participants with any known and discernable history of substance abuse and/or dependence.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 2

1. The primary efficacy endpoint is defined as the change from baseline in muscle force measurements as determined by dynamometry at Week 12.
2. Safety endpoints include incidence, severity, and relationship to SAT-3247 of adverse events as well as occurrence of clinically significant changes in physical examination, clinical laboratory measures, vital signs, ECG, and C-SSRS

Secondary endpoints 13

1. Changes from baseline in intramuscular fat fraction in muscle quantitative magnetic resonance (qMR) in vastus lateralis at Week 12
2. Changes from baseline in proton muscle transverse relaxation time (T2) in vastus lateralis at Week 12.
3. Changes from baseline in Regeneration Index in open muscle biopsy of the biceps brachii at Week 12
4. Changes from baseline in function as determined by NSAA assessment at Week 12
5. Changes from baseline in SV95C at Week 12
6. Exploratory end point: change from baseline in inflammatory cytokine profile at Week 12
7. Exploratory end point: change from baseline in creatine kinase at Week 12
8. Exploratory end point: change from baseline in maximum percent predicted forced vial capacity as measured by spirometry at Week 12
9. Exploratory end point: change in biceps brachii muscle fiber size and fiber size distribution as determined from histopathology at 12 weeks
10. Exploratory end point: change in the proportion of embryonic myosin positive fibers as determined from histopathology at 12 weeks.
11. Exploratory end point: change in the number of satellite cells as determined from histopathology at 12 weeks
12. Exploratory end point: change in endomysial fibrosis and adipose tissue infiltration as determined from histopathology at 12 weeks.
13. Exploratory end point: change in NSAA score over 12 weeks as compared to natural history

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 2

Placebo 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Satellos Bioscience Inc.

Sponsor organisation

Satellos Bioscience Inc.

Address

200 Bay Street Suite 2800

City

Toronto

Postcode

M5J 2J1

Country

Canada

Scientific contact point

Organisation

Satellos Bioscience Inc.

Contact name

Project Manager

Public contact point

Organisation

Satellos Bioscience Inc.

Contact name

Project Manager

Third parties 15

Locations

3 EU/EEA countries · 7 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 158 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

3 submissions — initial application plus substantial / non-substantial modifications