A Study of the Long-Term Safety and Efficacy of VX-670 in Patients With Myotonic Dystrophy Type I

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Vertex Pharmaceuticals Inc.

Participant type

Patients

Age range

18-64 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Musculoskeletal Diseases [C05]

Trial duration

25 Nov 2025 → ongoing

Decision date (initial)

2025-06-04

Transition trial

No

Low-intervention

No

Rare-disease indication

No

Vulnerable population

No

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Safety, Efficacy, Pharmacokinetic, Pharmacodynamic

To evaluate the long-term safety and tolerability of VX-670 in subjects with myotonic dystrophy type 1 (DM1)

Secondary objectives 1

1. To evaluate the plasma PK of VX-670 and PMO-0221a in subjects with DM1

Conditions and MedDRA coding

Myotonic Dystrophy

Regulatory references

Scientific advice from competent authorities

Food And Drug Administration

Plan to share IPD

No

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

1. 1. Subject (or his or her impartial witness if the subject is cognitively able to provide consent but unable to write) will sign and date an informed consent form (ICF).
2. 2. Subject must have completed an interventional VX-670 study (per interventional study completion definition) a. Study 001: Subjects in Part B must have received at least 2 doses of study drug.
3. 3. Willing and able to comply with scheduled visits, treatment plan, study restrictions, safety tests, contraceptive guidelines, and other study procedures.

Exclusion criteria 9

1. 1. History or evidence of any illness or any clinical condition (e.g. clinically significant kidney disease) that, in the opinion of the investigator or the subject’s general practitioner, might confound the results of the study or pose an additional risk in administering study drug to the subject. This may include but is not limited to major surgery, significant trauma, or clinically significant laboratory abnormalities (e.g., hypomagnesemia) within 4 weeks before the first study drug dose.
2. 2. Subject developed any VX-670-related serious or severe AE in the interventional study that, in the opinion of the sponsor, might pose an additional risk to the subject.
3. 3. For female subjects: Pregnant, nursing, or planning to become pregnant during the study or within 180 days after the last dose of study drug. For male subjects: Male subjects with a female partner who is pregnant, nursing, or planning to become pregnant during the study or within 180 days after the last dose of study drug.
4. 4. Use of the substances, activities, or devices as indicated in Section 9.4, during the specified times.
5. 5. Exposure to any investigational nucleic acid or cell and genetic therapy other than VX-670, including siRNA, ASO, mRNA within 6 months before Day 1 or 5 half-lives of investigational agent (confirmed at Screening), whichever is longer.
6. 6. Exposure to any cell and genetic therapies. Note that antisense oligonucleotides are not considered a genetic therapy.
7. 7. Exposure to any other investigational drugs or devices within 1 month before Day 1 or 5 half-lives before the first dose of study drug, whichever is longer
8. 8. Subject, or close relative of the subject, is the investigator or a subinvestigator, research assistant, pharmacist, study coordinator, or other staff directly involved with the conduct of the study at that site.
9. 9. Subject is an employee of the sponsor.

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. Safety and tolerability of VX-670 based on the assessment of adverse events (AEs), vital signs, electrocardiograms (ECGs), and clinical laboratory values

Secondary endpoints 1

1. VX-670 and PMO-0221a concentrations in plasma

Investigational products

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

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Vertex Pharmaceuticals Inc.

Sponsor organisation

Vertex Pharmaceuticals Inc.

Address

50 Northern Avenue

City

Boston

Postcode

02210-1862

Country

United States

Scientific contact point

Organisation

Vertex Pharmaceuticals Inc.

Contact name

Clinical Trials and Medical Info

Public contact point

Organisation

Vertex Pharmaceuticals Inc.

Contact name

Clinical Trials and Medical Info

Locations

6 EU/EEA countries · 6 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 74 files

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

Application history

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