A Study of Long-term Safety and Efficacy of VX-670 in Participants With Myotonic Dystrophy Type I

Phase 2

• Conditions: Myotonic Dystrophy Type 1 (DM1)
• Interventions: Drug: VX-670

• Registration Number: NCT06926621
• Lead Sponsor: Vertex Pharmaceuticals Incorporated

Brief 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).

Detailed Description

Not available

Study Timeline

• Status Verified: 2025-04
• Study First Submitted: 2025-04-10
• Study First Submitted QC: 2025-04-10
• Study First Posted: 2025-04-14
• Study Start: 2025-04-28
• Last Update Submitted: 2025-07-07
• Last Update Posted: 2025-07-08
• Primary Completion: 2028-07-24
• Study Completion: 2028-07-24

Recruitment & Eligibility

• Status: ENROLLING_BY_INVITATION
• Sex: All
• Target Recruitment: 36

Inclusion Criteria

• Completed study drug treatment in parent study VX23-670-001 (NCT06185764)

Key

Exclusion Criteria

• History of any illness or any clinical condition as pre-specified in the protocol

Other protocol defined Inclusion/Exclusion criteria may apply.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
VX-670	VX-670	Participants will receive multiple doses of VX-670.

Primary Outcome Measures

Name	Time	Method
Safety and Tolerability as Assessed by Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs)	From Day 1 up to Week 108

Secondary Outcome Measures

Name	Time	Method
Change From Baseline in Splicing Index in Muscle Biopsy at Week 24	Baseline and at Week 24
Maximum Observed Concentration (Cmax) of VX-670 and its Active Component in Plasma	From Day 1 up to Week 96
Area Under the Concentration Versus Time Curve (AUC) of VX-670 and its Active Component in Plasma	From Day 1 up to Week 96
Concentration of VX-670 and its Active Component in Muscle	Baseline and at Week 24

Trial Locations

Locations (5)

Leonard Wolfson Experimental Neurology Centre CRF; 🇬🇧 London, United Kingdom

Wesley Research Institute; 🇦🇺 Auchenflower, Australia

Neuroscience Clinical Trials Unit, Alfred Brain; 🇦🇺 Melbourne, Australia

Altasciences Montreal; 🇨🇦 Montreal, Canada

University of Ottawa; 🇨🇦 Ottawa, Canada