Myotonic Dystrophy Type 1 (DM1)Phase 2NCT06926621
A Study of Long-term Safety and Efficacy of VX-670 in Participants With Myotonic Dystrophy Type I
A Phase 2 study testing VX-670 in people with Myotonic Dystrophy Type 1 (DM1), run by Vertex Pharmaceuticals Incorporated at 16 sites in 8 countries.
Trial summary
The purpose of the study is to evaluate the long-term safety and tolerability, efficacy and pharmacokinetics of VX-670 in participants with Myotonic Dystrophy Type I (DM1). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Myotonic Dystrophy Type 1 (DM1)
- What is being tested?
- VX-670
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 44 participants
- Where
- 16 sitesin 8 countries
- Study dates
- 28 Apr 2025to 30 Jan 2029
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Completed study drug treatment in parent study VX23-670-001 (NCT06185764)
Who cannot join
- History of any illness or any clinical condition as pre-specified in the protocol
- Other protocol defined Inclusion/Exclusion criteria may apply.
Trial locations and contacts
16 sites in 8 countries. Contact the study team or a site near you to ask about taking part.
16 sites in 8 countries
Canada4 sites
Altasciences Montreal
Montreal
Montreal Neurological Institute-Hospital
Montreal
University of Ottawa
Ottawa
Universite Laval - Neurology
Québec
United States3 sites
Virginia Commonwealth University - Sanger Hall
Richmond, Virginia, 23298
St. Louis Children's Hospital - Neurology
St Louis, Missouri, 63110
Wake Forest Univ School of Medicine - Neurology
Winston-Salem, North Carolina, 27104
United Kingdom3 sites
Queen Elizabeth University Hospital - Neurology
Glasgow
Leonard Wolfson Experimental Neurology Centre CRF
London
Royal Hallamshire Hospital - Neurology
Sheffield
Australia2 sites
Wesley Research Institute
Auchenflower
Neuroscience Clinical Trials Unit, Alfred Brain
Melbourne
Belgium1 site
Universitaire Ziekenhuizen Leuven - Campus Gasthuisberg - Pulmonology
Leuven
About this study
Official title: An Open-label Extension Study Evaluating the Long-term Safety, Tolerability, Efficacy, Pharmacokinetics, and Pharmacodynamics of VX-670 in Adult Subjects With Myotonic Dystrophy Type I
The purpose of the study is to evaluate the long-term safety and tolerability, efficacy and pharmacokinetics of VX-670 in participants with Myotonic Dystrophy Type I (DM1).
- Conditions
- Myotonic Dystrophy Type 1 (DM1)
- Being tested
- VX-670
- Keywords
- DM 1, Myotonic Dystrophy 1, Myotonic Dystrophy Type 1 (DM1), VX-670, Myotonic Dystrophy, DM, Myotonia, Dystrophy Myotonic, Myotonic Disorders, Steinert Disease, Vertex, Entrada, PMO, ASO, Myotonic Muscular Dystrophy, Muscular Disorders, Atrophic, Muscular Diseases, Musculoskeletal Diseases, Neuromuscular Diseases, Nervous System Diseases
- Medical subject headings
- Myotonic Dystrophy, Myotonia, Myotonic Disorders, Muscular Disorders, Atrophic, Muscular Diseases, Musculoskeletal Diseases, Neuromuscular Diseases, Nervous System Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
VX-670Drug
Solution for intravenous administration.
| Study group | Role | What they receive |
|---|---|---|
| VX-670 | Experimental | Participants will receive multiple doses of VX-670. Receives: Drug: VX-670 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Safety and Tolerability as Assessed by Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
Measured: From Day 1 up to Week 108
Secondary outcomes (2)
Maximum Observed Concentration (Cmax) of VX-670 and its Active Component in Plasma
Measured: From Day 1 up to Week 96
Area Under the Concentration Versus Time Curve (AUC) of VX-670 and its Active Component in Plasma
Measured: From Day 1 up to Week 96
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Apr 2025
- Study start28 Apr 2025
- Primary completion30 Jan 2029 (estimated)
- Study completion30 Jan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Myotonic Dystrophy Type 1 (DM1)Studies of the same condition, open and under way.
- More trials run by Vertex Pharmaceuticals IncorporatedThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 44 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vertex Pharmaceuticals Incorporated
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06926621
- Sponsor's protocol ID
- VX24-670-101
- Other IDs
- 2024-517983-47-00
- Status last verified
- Oct 2026
- First submitted
- 10 Apr 2025
- Last updated
- 14 Oct 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/
Study at a glance
From the registry record, last updated by the sponsor on 14 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-label Extension Study Evaluating the Long-term Safety, Tolerability, Efficacy, Pharmacokinetics, and Pharmacodynamics of VX-670 in Adult Subjects With Myotonic Dystrophy Type I
- ClinicalTrials.gov ID
- NCT06926621
- Acronym / sponsor ID
- VX24-670-101
- Conditions
- Myotonic Dystrophy Type 1 (DM1)
- Keywords
- DM 1, Myotonic Dystrophy 1, Myotonic Dystrophy Type 1 (DM1), VX-670, Myotonic Dystrophy, DM, Myotonia, Dystrophy Myotonic
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 44 participants (estimated)
- Lead sponsor
- Vertex Pharmaceuticals IncorporatedIndustry (pharma, biotech, devices)
- Study start
- 28 Apr 2025 (actual)
- Primary completion
- 30 Jan 2029 (estimated)
- Study completion
- 30 Jan 2029 (estimated)
- First posted
- 14 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the study is to evaluate the long-term safety and tolerability, efficacy and pharmacokinetics of VX-670 in participants with Myotonic Dystrophy Type I (DM1).
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| VX-670 | Experimental | Drug: VX-670Participants will receive multiple doses of VX-670. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Completed study drug treatment in parent study VX23-670-001 (NCT06185764)
Key exclusion criteria (2 listed)
- History of any illness or any clinical condition as pre-specified in the protocol
- Other protocol defined Inclusion/Exclusion criteria may apply.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| VX-670Solution for intravenous administration. | Drug | VX-670 |
Primary outcome
Safety and Tolerability as Assessed by Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)
Time frame: From Day 1 up to Week 108
2 secondary outcomes
Maximum Observed Concentration (Cmax) of VX-670 and its Active Component in Plasma
Time frame: From Day 1 up to Week 96
Area Under the Concentration Versus Time Curve (AUC) of VX-670 and its Active Component in Plasma
Time frame: From Day 1 up to Week 96
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Oct 2026.
- Individual participant dataSharing planned: No. Details on Vertex data sharing criteria and process for requesting access can be found at: https://www.vrtx.com/our-science/clinical-trials-data-sharing/
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
16 sites in 8 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing VX-670 in people with Myotonic Dystrophy Type 1 (DM1), run by Vertex Pharmaceuticals Incorporated at 16 sites in 8 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 14 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 16 sites in Canada, United States, United Kingdom, Australia, Belgium and 3 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Safety and Tolerability as Assessed by Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs) (time frame: From Day 1 up to Week 108). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Oct 2026.