A phase I trial of DT-818 in healthy volunteers and adults with myotonic dystrophy type 1
| ISRCTN | ISRCTN79964452 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN79964452 |
| Secondary identifying numbers | DTX-818-101 |
- Submission date
- 05/11/2025
- Registration date
- 07/11/2025
- Last edited
- 07/11/2025
- Recruitment status
- Not yet recruiting
- Overall study status
- Ongoing
- Condition category
- Nervous System Diseases
Plain English summary of protocol
Background and study aims
This is a phase I, open-label, multiple dose-escalation study to assess the safety, tolerability, and pharmacokinetics (PK; how a drug moves through the body) of DT-818 in adult healthy participants, and in adult patients with myotonic dystrophy
Who can participate?
Healthy adult volunteers and adult patients with genetically confirmed myotonic dystrophy Type 1 (DM1).
What does the study involve?
The trial includes subcutaneous (SC) infusion and intravenous (IV) infusion administration routes, with multiple ascending dose cohorts. Assessments include adverse events, vital signs, ECGs, labs, and PK sampling.
What are the possible benefits and risks of participating?
Benefits and risks not provided at registration
Where is the study run from?
Design Therapeutics, Inc.
When is the study starting and how long is it expected to run for?
September 2025 to December 2027
Who is funding the study?
Design Therapeutics, Inc.
Who is the main contact?
Study Manager, info@designtx.com
Contact information
Principal investigator
Level 4, 10 St Andrews Place
East Melbourne
3121
Australia
| Phone | +61 (03) 9970 4200 |
|---|---|
| tfrisby@dohertyclinicaltrials.com |
Public, Scientific
6005 Hidden Valley Road
Suite 110
Carlsbad
92011
United States of America
| Phone | +1 858-293-4900 |
|---|---|
| info@designtx.com |
Study information
| Study design | Open-label non-randomized interventional phase I multicenter study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Non randomised study |
| Study setting(s) | Pharmaceutical testing facility |
| Study type | Safety, Other |
| Participant information sheet | Not available in web format, please use contact details to request a participant information sheet. |
| Scientific title | A phase 1, open-label trial to assess the safety and pharmacokinetics of multiple ascending doses of DT-818 in healthy volunteers and participants with myotonic dystrophy type 1 |
| Study objectives | To assess the safety, tolerability, and pharmacokinetics (PK) of DT-818 |
| Ethics approval(s) |
Approved 29/10/2025, Bellberry Human Research Ethic Committee (Level 1, 196 Greenhill Road Eastwood, Adelaide, 5063, Australia; +61 08 8361 3222; bellberry@bellberry.com.au), ref: DTX-818-101 |
| Health condition(s) or problem(s) studied | Myotonic dystrophy (DM1) |
| Intervention | DT-818 will be administered in an open-label fashion to healthy participants (Cohort 1) and then to participants with myotonic dystrophy type 1 (DM1, Cohorts 2-6). Each sequential Cohort will receive weekly administrations of DT-818, intravenously or subcutaneously, in a 28-day cycle. The first and 5th doses will require an overnight stay for full PK analysis. Other doses will be administered as an outpatient in the research unit. The dose and subsequent dose escalations will be determined by a safety review committee. DM1 participants will undergo a muscle biopsy before and at the end of treatment to look for the impact of DT-818 on splicing. Total study participation duration is estimated to be approximately four months. |
| Intervention type | Drug |
| Pharmaceutical study type(s) | Pharmacokinetic, Pharmacodynamic, Dose response |
| Phase | Phase I |
| Drug / device / biological / vaccine name(s) | DT-818 |
| Primary outcome measure | Safety of DT-818 measured using data collected from electronic Case Report Forms (CRF), including incidence of Treatment Emergent Adverse Events (TEAEs), including Serious Adverse Events (SAEs), from enrollment to end of study |
| Secondary outcome measures | Characterization of the PK profile of DT-818 measured using plasma PK parameters, including but not limited to AUClast, AUCinf, Cmax, t1/2, from first dose to end of study, from enrollment to end of study |
| Overall study start date | 24/09/2025 |
| Completion date | 01/12/2027 |
Eligibility
| Participant type(s) | Healthy volunteer, Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Upper age limit | 65 Years |
| Sex | All |
| Target number of participants | 44 |
| Key inclusion criteria | Healthy Volunteers (Cohort 1) 1. Male or female participants, 18–55 years of age, inclusive. 2. Medically healthy with no clinically significant abnormalities based on medical history, physical exam, vital signs, ECG, and clinical laboratory tests at screening. 3. Negative tests for drugs of abuse, alcohol, hepatitis B surface antigen, hepatitis C antibody, and HIV. 4. Willing and able to comply with study restrictions and provide written informed consent. 5. Women of childbearing potential must use highly effective contraception from screening through the end of the study; men must use contraception and refrain from sperm donation for the same period. DM1 Participants (Cohort 2 and beyond) 1. Adults 18–65 years of age with genetically confirmed Myotonic Dystrophy Type 1 (DM1). 2. Stable clinical status and medications for ≥1 month prior to screening. 3. Able and willing to comply with study visits, assessments, and treatment requirements. 4. Provides written informed consent (and caregiver consent, if applicable). |
| Key exclusion criteria | 1. History or presence of any clinically significant cardiovascular, hepatic, renal, gastrointestinal, respiratory, hematologic, or neurologic disease (other than DM1 for patient cohorts). 2. Clinically significant ECG findings per protocol defined limits 3. Abnormal laboratory values at screening or per protocol-defined laboratory limits. 4. Participation in another investigational drug or device study within 90 days prior to dosing. 5. Positive test for alcohol or drugs of abuse at screening or admission. 6. Pregnant or breastfeeding women. 7. Any condition that, in the opinion of the investigator, would make the participant unsuitable for the study. |
| Date of first enrolment | 01/12/2025 |
| Date of final enrolment | 01/09/2027 |
Locations
Countries of recruitment
- Australia
Study participating centres
3002
Australia
2031
Australia
Sponsor information
Industry
6005 Hidden Valley Road
Suite 110
Carlsbad
92011
United States of America
| Phone | +1 858-293-4900 |
|---|---|
| info@designtx.com |
Funders
Funder type
Industry
No information available
Results and Publications
| Intention to publish date | 01/12/2028 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not expected to be made available |
| Publication and dissemination plan | Planned publication in peer-reviewed journal |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are not expected to be made available due to participant privacy/confidentiality concerns given rare disease population. |
Editorial Notes
06/11/2025: Studys' existence confirmed by the Bellberry Human Research Ethic Committee, Australia.
