Clinical trial NCT06254482: An Extension Study to Evaluate the Long-Term Safety and Efficacy of PTC518 in Participants With Huntington's Disease (HD)
Official title: A Phase 2b, Double-Blind, Randomized Extension Study to Evaluate the Long-Term Safety and Efficacy of PTC518 in Participants With Huntington's Disease
Study type: INTERVENTIONAL
Overall status: ENROLLING_BY_INVITATION
Phase: PHASE2
Conditions: Huntington Disease
Keywords: Neurodegenerative disorder
Rare disease
Lead sponsor: PTC Therapeutics
Sponsor class: INDUSTRY
First posted: 2024-02-12
Enrollment: 250
Sex: ALL
Minimum age (years): 25
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: The primary goal of this study is to evaluate the long-term safety and pharmacodynamic effects of PTC518 in participants with HD.

Detailed description: Participants who completed the Treatment Period in the parent Phase 2a Study PTC518-CNS-002-HD (NCT05358717), fulfilled the enrollment criteria, and chose to enroll in this extension study will undergo baseline evaluations and be assessed for 30 additional months.

All participants will receive active PTC518 in this extension study. Participants who received PTC518 in the parent Study PTC518-CNS-002-HD will continue at the same dose level they received in that study in a blinded fashion (5, 10, or 20 milligrams \[mg\]). Participants who received placebo in the parent Study PTC518-CNS-002-HD will be allocated to a PTC518 dose level according to the same dosing group in which they were previously randomized (5, 10, or 20 mg). The 20 mg dosing arm will be open for randomization only if and when the Data Safety and Monitoring Board from the parent Study PTC518-CNS-002-HD recommends initiating this dosing level based on an unblinded review of safety data from that study.

Eligibility criteria: Inclusion Criteria:

* Participant who has completed the Treatment Period in Study PTC518-CNS-002-HD.

Exclusion Criteria:

* Participants who have not previously completed the Treatment Period in Study PTC518-CNS-002-HD.

Note: Other inclusion and exclusion criteria may apply.

Primary outcomes:
measure: Number of Participants With Treatment-emergent Adverse Events (TEAEs)
timeFrame: Baseline up to Month 30
measure: Blood Total Huntingtin Protein (tHTT) Levels
timeFrame: Baseline up to Month 28
Secondary outcomes:
measure: Change From Baseline in Caudate Volume as Assessed Via Volumetric Magnetic Resonance Imaging (vMRI) at Month 24
timeFrame: Baseline, Month 24
measure: Change From Baseline in Composite Unified Huntington's Disease Rating Scale (cUHDRS) Scores at Month 24
timeFrame: Baseline, Month 24
measure: Cerebrospinal Fluid (CSF) Mutant Huntingtin Protein (mHTT) Levels
timeFrame: Baseline up to Month 24
measure: Blood mHTT Protein Levels
timeFrame: Baseline up to Month 28
Other outcomes:
Locations:
city: Clayton
country: Australia
facility: Monash Health
city: Westmead
country: Australia
facility: Westmead Hospital
city: Innsbruck
country: Austria
facility: Medical University Innsbruck
city: Ottawa
country: Canada
facility: The Ottawa Hospital, Parkinson's and Movement Disorders Clinic
city: Angers
country: France
facility: Centre Hospitalier Universitaire d'Angers
city: Marseille
country: France
facility: Hôpital Universitaire de Marseille Hôpital de la Timone
city: Paris
country: France
facility: Brain and Spine institute Paris
city: Berlin
country: Germany
facility: Charite University Medicine Berlin
city: Bochum
country: Germany
facility: Ruhr-Univ. Bochum St. Joseph-Hospital
city: Münster
country: Germany
facility: George-Huntington-Institut
city: Ulm
country: Germany
facility: Ulm University, UKU, Dep. of Neurology
city: Bologna
country: Italy
facility: Irccs Istituto Delle Scienze Neurologiche Di Bologna Uoc Clinica Neurologica
city: Milan
country: Italy
facility: IRCCS Carlo Besta Neurological Institutte
city: San Giovanni Rotondo
country: Italy
facility: IRCCS Casa Sollievo della Sofferenza Research Hospital
city: Leiden
country: Netherlands
facility: Leiden University Medical Center
city: Christchurch
country: New Zealand
facility: University of Otago, New Zealand Brain Research Institute
city: Barakaldo
country: Spain
facility: Hospital Universitario Cruces
city: Barcelona
country: Spain
facility: Hospital de la Santa Creu I Sant Pau
city: Burgos
country: Spain
facility: Hospital Universitario Burgos
city: Madrid
country: Spain
facility: Hospital Ramón y Cajal
city: Birmingham
country: United Kingdom
facility: The Barbery National Centre for Mental Health
city: Cardiff
country: United Kingdom
facility: University Hospital of Wales
city: London
country: United Kingdom
facility: UCL Queen Square Institute of Neurology National Hospital for Neurology and Neurosurgery
city: Manchester
country: United Kingdom
facility: Manchester University NHS Foundation Trust
Study officials:
References: