Antioxidant Therapy in RYR1-Related Congenital Myopathy

NCT ID: NCT02362425

Last Updated: 2019-12-24

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE1/PHASE2
• Total Enrollment: 63 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2015-02-12
• Study Completion Date: 2018-05-30

Brief Summary

Background:

• Ryanodine receptor type 1-related myopathies (RYR1-RM) are the most common non-dystrophic muscle diseases that people are born with in the U.S. They affect development, muscles, and walking. Researchers want to test a new drug to help people with these diseases.

Objectives:

• To see if the drug N-acetylcysteine decreases muscle damage in people with RYR1-RM. To see if it improves their exercise tolerance.

Eligibility:

• People age 7 and older with a confirmed genetic diagnosis of RYR1 or a clinical diagnosis of RYR1 and a family member with a confirmed genetic diagnosis.

Design:

• Participants will be screened with a checklist of criteria. Adult participants may have a muscle biopsy. A needle will remove a tiny piece of muscle in the lower leg.
• Study visits will take several days.
• Visit 1:
• Medical history
• Physical exam
• Blood, urine, and saliva tests
• Questions about symptoms and quality of life
• Heart, lung, and walking tests
• Muscle Oxygenation Capacity Test. A blood pressure cuff around the thigh will be tightened for up to 10 minutes.
• Biodex testing, stretching the leg against resistance
• Muscle ultrasounds. A probe will be moved over the skin.
• Participants may be photographed or videotaped during procedures.
• They may have a muscle biopsy.
• Six months later, visit 2 will repeat visit 1. Participants will start taking the study drug dissolved in water or placebo three times a day for 6 months.
• Participants will stay at NIH for 2 days after starting the study drug.
• Participants will be contacted by phone during the study to monitor side effects
• Six months after starting the study drug, study visit 3 will repeat some or all of visit 1.

Detailed Description

Although genetic disorders of muscle that present at birth are rare, RYR1-related myopathies comprise the most common non-dystrophic congenital myopathy in the United States, with a prevalence of approximately 1/90,000 people (Amburgey et al, 2011). Causative mutations in the ryanodine receptor gene of skeletal muscle, RYR1, have been found in several myopathy subtypes, including central core disease and centronuclear myopathy. These mutations result in defective excitation-contraction coupling and increased mitochondrial oxidative stress. Most patients present in childhood with delayed motor milestones, extremity muscle weakness, impaired ambulation, joint contractures, progressive scoliosis, and in some cases eye movement paralysis, respiratory failure, or susceptibility to malignant hyperthermia, an allelic condition. Despite these important morbidities and the risk of early mortality, no treatments exist to date.

RYR1 encodes a homotetrameric transmembrane ion channel, RyR1, which resides on the terminal sarcoplasmic reticulum in close proximity to the T-tubule. By releasing calcium from the sarcoplasmic reticulum into the cytosol in response to muscle fiber stimulation by the motor neuron at the neuromuscular junction, it mediates excitation-contraction coupling and functions as a regulator of cellular calcium concentrations and redox homeostasis. Dowling et al. (2012) recently elucidated the latter mechanism in zebrafish and patient myotubes, showing that RYR1 mutations result in increased oxidative stress and that this is rescued in both models by treatment with N-acetylcysteine (NAC), a known anti-oxidant. NAC functions as a precursor of glutathione, an endogenous antioxidant that becomes deficient during oxidative stress. This was substantiated by a cystic fibrosis clinical trial in which low glutathione levels in neutrophils undergoing oxidative stress significantly increased with NAC administration.

Dowling et al. (2012) found significant changes post NAC treatment including increased travel distance (endurance) in zebrafish and complete protection from cell death induced by experimentally increasing oxidative stress in myotubes. Thus NAC was a successful treatment in both ex vivo and in vivo model systems. Based on these results, we plan to perform a randomized, double-blinded, placebo controlled clinical trial of NAC in a subgroup of RYR1-related myopathy patients as the first pathophysiologically based treatment for this devastating disorder.

The objectives of the study are to determine if NAC reduces oxidative stress, fatigability, and fatigue in a study population of patients with RYR1-RM. The study population includes both males and females 7 years of age and older. The study design has two phases. The first 6-month phase will be used to validate the selected outcome measures in RYR1 congenital myopathy. The second 6-month phase is a randomized, double-blinded, placebo controlled drug intervention trial. The primary outcome measures are blood glutathione for oxidative stress and six minute walk test for fatigability. Healthy volunteers will be evaluated to determine normal values of biomarkers, muscle ultrasound, and near infrared spectroscopy in this rare disease, in order to develop a comparison between healthy and RYR1-RM individuals.

Conditions

Neuromuscular Disease

Keywords

Neuromuscular Disease; Clinical Trial; Ryanodine Receptor Type 1; Myopathy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

RYR1-RM Patients Administered N-acetylcysteine

N-acetylcysteine

Group Type: ACTIVE_COMPARATOR

N-acetylcysteine

Intervention Type: DRUG

RYR1-RM Patients Administered Placebo

Placebo

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

Healthy Volunteers

Healthy volunteers who had physical exam, study biomarker, Near Infrared Spectroscopy (NIRS) testing and muscle ultrasound only, in one visit.

Group Type: NO_INTERVENTION

No interventions assigned to this group

Interventions

N-acetylcysteine

Intervention Type: DRUG

Placebo

Intervention Type: DRUG

Eligibility Criteria

Exclusion Criteria

• Adults who cannot provide their own consent and pediatric participants who do not have a parent able to provide consent.
• Patients with a history of liver disease (Liver Function Tests will be collected at baseline and

at each study visit as a precautionary measure). Liver disease is defined as moderate to severe hepatic impairment based on the following:

• Alanine Aminotransferase (ALT) greater than or equal to 8x upper limit of normal (ULN) with total bilirubin 2x ULN (plus >35% direct bilirubin) and/or International normalized ratio (INR) >1.5 or
• Gamma-glutamyl transferase (GGT) > 2-3x ULN with bilirubin 2x ULN (plus >35% direct bilirubin) and/or INR

• Patients with a history of peptic ulcers, gag reflex depression, and esophageal varices. Patients with gastrostomy tubes may be considered for participation, in the case of gag reflex depression or other swallowing or feeding difficulties.
• Patients who have a severe pulmonary dysfunction (FEV1< 40% predicted) or evidence of pulmonary exacerbation. Pulmonary exacerbations refer to an acute worsening of respiratory symptoms that result from a decline in lung function. Participants may present with increased coughing, increased dyspnea, increased haemoptysis, increased fatigue, decreased pulmonary function by a min of 10%, or a change in sputum color.
• Pregnant and breastfeeding women.
• Consumption of antioxidants [including NAC, GSH, melatonin, Immunocal (Immunotac

Research, Vandreuil-Dorion, QC, Canada), Nacystelyn (Galephar, Brussels)] in the 4 weeks before recruitment.

-Daily use of acetaminophen (including Percocet, Vicodin, Oxycodone, Excedrin, and other

acetaminophen-containing drugs), nitroglycerine, or carbamazepine during the past 7 days.

• Current use of Angiotensin-converting enzyme (ACE) inhibitors or Angiotensin Receptor Blockers (ARBs).
• Patients who have ever used Beta2-adrenergic agonist tablets, for the purpose of increasing muscle mass (such as albuterol tablets).
• For the muscle biopsy procedure only (second and third visits, if applicable): Patients who have taken Aspirin, Ibuprofen, Advil, Motrin, or Aleve within the 3 days prior to the muscle biopsy procedure, and/or patients who have taken Plavix, fresh garlic, gingko, or ginseng 5 days prior to the muscle biopsy.
• Participation in trials for other therapeutic investigational drugs simultaneously or 4 weeks before recruitment.
• Other clinically significant medical disease that, in the judgment of the investigators, would expose the patient to undue risk of harm or prevent the patient from completing the study. Examples include anemia (defined as Hgb < 8 gm/dl), an inability to walk safely without assistance for at least 6 minutes, and/or an inability to consume at least 6 ounces of fluid, 3 times a day, either orally or via G-tube. Patients with comorbidities (i.e. cancer, epilepsy) will be carefully assessed to determine if their comorbidity could lead to confounding or safety issues, should their participation continue.

• Diagnosis of RYR1-related myopathy or other neurological disorder (by neurological exam, genetic testing, or muscle biopsy
• Complaints of fatigue or weakness
• Consumption of antioxidants [including NAC, GSH, melatonin, Immunocal (Immunotac
• Research, Vandreuil-Dorion, QC, Canada), Nacystelyn (Galephar, Brussels)] in the 4 weeks before recruitment.
• Use of Beta2-adrenergic agonists.

• Minimum Eligible Age: 7 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Institute of Nursing Research (NINR)

NIH

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Suzanne J Wingate, C.R.N.P.

Role: PRINCIPAL_INVESTIGATOR

National Institute of Nursing Research (NINR)

Locations

National Institutes of Health Clinical Center, 9000 Rockville Pike

Bethesda, Maryland, United States

Countries

United States

References

Chin LMK, Todd JJ, Chrismer IC, Witherspoon JW, Jain M, Waite M, Meilleur KG, Drinkard B, Lawal TA. Exercise capacity in RYR1-related myopathies. Orphanet J Rare Dis. 2025 Sep 24;20(1):485. doi: 10.1186/s13023-025-04013-7.

Reference Type: DERIVED

PMID: 40993798 (View on PubMed)

Greer LK, Meilleur KG, Harvey BK, Wires ES. Identification of ER/SR resident proteins as biomarkers for ER/SR calcium depletion in skeletal muscle cells. Orphanet J Rare Dis. 2022 Jun 13;17(1):225. doi: 10.1186/s13023-022-02368-9.

Reference Type: DERIVED

PMID: 35698232 (View on PubMed)

Todd JJ, Lawal TA, Witherspoon JW, Chrismer IC, Razaqyar MS, Punjabi M, Elliott JS, Tounkara F, Kuo A, Shelton MO, Allen C, Cosgrove MM, Linton M, Michael D, Jain MS, Waite M, Drinkard B, Wakim PG, Dowling JJ, Bonnemann CG, Emile-Backer M, Meilleur KG. Randomized controlled trial of N-acetylcysteine therapy for RYR1-related myopathies. Neurology. 2020 Mar 31;94(13):e1434-e1444. doi: 10.1212/WNL.0000000000008872. Epub 2020 Jan 15.

Reference Type: DERIVED

PMID: 31941795 (View on PubMed)

Witherspoon JW, Vasavada RP, Waite MR, Shelton M, Chrismer IC, Wakim PG, Jain MS, Bonnemann CG, Meilleur KG. 6-minute walk test as a measure of disease progression and fatigability in a cohort of individuals with RYR1-related myopathies. Orphanet J Rare Dis. 2018 Jul 3;13(1):105. doi: 10.1186/s13023-018-0848-9.

Reference Type: DERIVED

PMID: 29970108 (View on PubMed)

Provided Documents

Document Type: Study Protocol

View Document

Document Type: Statistical Analysis Plan

View Document

Related Links

https://clinicalstudies.info.nih.gov/cgi/detail.cgi?B_2015-NR-0072.html

NIH Clinical Center Detailed Web Page

Other Identifiers

15-NR-0072

Identifier Type: -

Identifier Source: secondary_id

150072

Identifier Type: -

Identifier Source: org_study_id