Antioxidant Therapy in RYR1-Related Congenital Myopathy (RYR1)

Title: 
Antioxidant Therapy in RYR1-Related Congenital Myopathy (RYR1)
Recruitment Status: 
Status Last Updated: 
December 24, 2019
Clinical Phenotype(s): 
Gene(s): 
Study Purpose: 

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.

Intervention/Treatment: 
Drug: N-acetylcysteine (NAC)
Study 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.

Study Type: 
Official Title: 
Antioxidant Therapy in RYR1-Related Congenital Myopathy
Study Start Date: 
February 12, 2015
Study Completion Date: 
May 30, 2018
Primary Objective(s): 
  1. Urine 15-F2t Isoprostane Concentration [ Time Frame: 12 months ] - Urine will be assayed for 15-isoprostane-F2, which is formed when arachidonic acid reacts with reactive oxygen species(ROS). A validated gas chromatography(GC)-mass spectrometer (MS) method will be used to quantify 15-isoprostane-F2
  2. Six Minute Walk Test (6MWT) [ Time Frame: 12 months ] - Meters walked in 6 minutes will be recorded; distances in meters will be recorded at each minute interval; speed will be calculated.
Secondary Objective(s): 
  1. DCF-fluorescence Intensity (AU) [ Time Frame: 12 months ] - Dichlorodihydrofluorescein (DCFH) will be used on participate muscle biopsies to analyze intracellular oxidant activity [H2DCFDA (H2-DCF, DCF)].
  2. Time to Ascend Steps (Seconds) [ Time Frame: 12 months ] - Participants completed the following timed function tests: supine to stand, ascend four steps, descend four steps, and walk/run 10 meters. For time taken to ascend four steps, the subject was asked to ascend four steps whilst being timed.
  3. Descend Steps [ Time Frame: 12 months ] - Participants completed the following timed function tests: supine to stand, ascend four steps, descend four steps, and walk/run 10 meters. For time taken to descend four steps, the subject was asked to descend four steps whilst being timed.
  4. Walk/Run 10 Meters [ Time Frame: 12 months ] - Participants completed the following timed function tests: supine to stand, ascend four steps, descend four steps, and walk/run 10 meters. For walk/run 10 meters, participants were timed as they walked/ran a marked 10-meter course as quickly as possible.
  5. Supine to Stand [ Time Frame: 12 months ] - Participants completed the following timed function tests: supine to stand, ascend four steps, descend four steps, and walk/run 10 meters. For time taken to transition from supine to standing, participants were asked to lay supine and then the time taken to move from supine to standing was recorded.
  6. Motor Function Measure-32 (MFM-32) Domain 1 (D1) [ Time Frame: 12 months ] - Motor Function Measure, MFM-32 is a well-established scale of motor function in congenital muscle disease. The D1 domains measure standard and transfers, and consist of 13 items. Generic Values for each domain are: 0 = cannot perform the task, 1 = initiated the task, 2 - performs the movement incompletely, or completely but imperfectly, 3 = performs the task fully and 'normally'. Total score is the sum of all the domains for D1 divided by the maximum score possible and multiplied by 100. Min=0, Max = 100. Lower numbers on the scale represent a worse outcome.
  7. Motor Function Measure-32 (MFM-32) Domain 2 (D2) [ Time Frame: 12 months ] - Motor Function Measure, MFM-32 is a well-established scale of motor function in congenital muscle disease. The D2 domains measure axial and proximal motor function and consists of 12 items. Generic Values for each domain are: 0 = cannot perform the task, 1 = initiated the task, 2 - performs the movement incompletely, or completely but imperfectly, 3 = performs the task fully and 'normally'. The total score is the sum of all the MFM-32 domains for D2, divided by maximum score possible and multiplied by 100. Min = 0, Max = 100. Lower numbers on the scale represent a worse outcome.
  8. Motor Function Measure-32 (MFM-32) Domain 3 (D3) [ Time Frame: 12 months ] - Motor Function Measure, MFM-32 is a well-established scale of motor function in congenital muscle disease. The D3 domains measure distal motor function and consist of 7 items. Generic Values for each domain are: 0 = cannot perform the task, 1 = initiated the task, 2 - performs the movement incompletely, or completely but imperfectly, 3 = performs the task fully and 'normally'. The total score is the sum of all the MFM-32 domains for D3, divided by maximum score possible and multiplied by 100. Min = 0, Max = 100. Lower numbers on the scale represent a worse outcome.
  9. Motor Function Measure-32 (MFM-32) Total Score [ Time Frame: 12 months ] - Motor Function Measure, MFM-32 is a well-established scale of motor function in congenital muscle disease. Generic Values for each domain are: 0 = cannot perform the task, 1 = initiated the task, 2 - performs the movement incompletely, or completely but imperfectly, 3 = performs the task fully and 'normally'. The total score is the sum of all the MFM-32 domains, divided by maximum score possible (96) and multiplied by 100. Min = 0, Max = 100. Lower numbers on the scale represent a worse outcome.
  10. Hand Grip Strength [ Time Frame: 12 months ] - Grip and pinch strength were determined using Myotools dynamometry. The myogrip hand held dynamometer was used to assess grip strength. Higher scores represent better outcomes.
  11. Hand Pinch Strength [ Time Frame: 12 months ] - Grip and pinch strength were determined using Myotools dynamometry. The myopinch pinch gauge was used to measure finger strength. Higher scores represent better outcomes.
  12. Peak Torque Flexion [ Time Frame: 12 months ] - Lower-body isometric strength testing was used to determine peak torque during flexion and extension. Participant's blood pressure was assessed, to rule-out hypertension (>140/90), prior to starting the test. Participants were then asked to push against a stationary arm and remained at the same joint angle for the duration of each test. Two short trials were completed to establish maximal force for each participant. This was followed by a long trial of flexion and extension to capture rate of fatigue to 50% after reaching their pre-determined maximal force. In the interest of safety, participants with hypertension and/or a history of knee injury did not perform the test.
  13. Peak Torque Extension [ Time Frame: 12 months ] - Lower-body isometric strength testing was used to determine peak torque during flexion and extension. Participant's blood pressure was assessed, to rule-out hypertension (>140/90), prior to starting the test. Participants were then asked to push against a stationary arm and remained at the same joint angle for the duration of each test. Two short trials were completed to establish maximal force for each participant. This was followed by a long trial of flexion and extension to capture rate of fatigue to 50% after reaching their pre-determined maximal force. In the interest of safety, participants with hypertension and/or a history of knee injury did not perform the test.
  14. Adult Patient-Reported Outcomes Measurement Information System (PROMIS) - Fatigue [ Time Frame: 12 months ] - Participants were asked to complete the PROMIS (patient-reported outcomes measurement information system) through the NIH online, self-administered Clinical Trials Survey System. PROMIS scores are normed to 100 meaning that the raw score is converted to a scale where 50 is the mean and the standard deviation is 10. Scores less than 50 indicate less fatigue compared to the average and scores over 50 indicate more fatigue than the average. Lower scores represent better outcomes.
  15. Adult Quality of Life in Neurological Disorders (NeuroQoL) Fatigue [ Time Frame: 12 months ] - Participants were asked to complete the NeuroQoL questionnaire through the NIH online, self-administered Clinical Trials Survey System. The NeuroQoL scores were normed to 100, meaning that the raw score is converted to a scale where 50 is the mean and the standard deviation is 10. Scores less than 50 indicate less fatigue compared to the average and scores over 50 indicate more fatigue than the average. Lower scores represent better outcomes.
  16. Pediatric Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue [ Time Frame: 12 months ] - Participants were asked to complete the PROMIS questionnaire through the NIH online, self-administered Clinical Trials Survey System. PROMIS scores were normed to 100 meaning that the raw scores were converted to a scale where 50 is the mean and the standard deviation is 10. Scores less than 50 indicate less fatigue compared to the average and scores over 50 indicate more fatigue than the average. Lower scores represent better outcomes.
  17. Pediatric Quality of Life in Neurological Disorders (NeuroQoL) Fatigue [ Time Frame: 12 months ] - Participants were asked to complete the NeuroQoL questionnaire through the NIH online, self-administered Clinical Trials Survey System. NeuroQoL scores were normed to 100 meaning that the raw score is converted to a scale where 50 is the mean and the standard deviation is 10. Scores less than 50 indicate less fatigue compared to the average and scores over 50 indicate more fatigue than the average. Lower scores represent better outcomes.
  18. Multidimensional Fatigue Inventory - 20 (MFI-20) General Fatigue Score [ Time Frame: 12 months ] - Participants were asked to complete the MFI-20 questionnaire through the NIH online, self-administered Clinical Trials Survey System. The MFI consists of 5 subscales: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Values range from 4-20 for each scale. Higher scores represent increased fatigue/ worse outcome.
  19. Multidimensional Fatigue Inventory-20 (MFI-20) Physical Fatigue Score [ Time Frame: 12 months ] - Participants were asked to complete the MFI-20 questionnaire through the NIH online, self-administered Clinical Trials Survey System. The MFI consists of 5 subscales: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Values range from 4-20 for each scale. Higher scores represent increased fatigue/ worse outcome.
  20. Multidimensional Fatigue Inventory-20 (MFI-20) Reduced Activity Score [ Time Frame: 12 months ] - Participants were asked to complete the MFI-20 questionnaire through the NIH online, self-administered Clinical Trials Survey System. The MFI consists of 5 subscales: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Values range from 4-20 for each scale. Higher scores represent increased fatigue/ worse outcome.
  21. Multidimensional Fatigue Inventory-20 (MFI-20) Reduced Motivation Score [ Time Frame: 12 months ] - Participants were asked to complete the MFI-20 questionnaire through the NIH online, self-administered Clinical Trials Survey System. The MFI consists of 5 subscales: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Values range from 4-20 for each scale. Higher scores represent increased fatigue/ worse outcome.
  22. Multidimensional Fatigue Inventory-20 (MFI-20) Mental Fatigue Score [ Time Frame: 12 months ] - Participants were asked to complete the MFI-20 questionnaire through the NIH online, self-administered Clinical Trials Survey System. The MFI consists of 5 subscales: general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation. Values range from 4-20 for each scale. Higher scores represent increased fatigue/ worse outcome.
  23. Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) Total Score [ Time Frame: 12 months ] - Participants were asked to complete the FACIT-f questionnaire through the NIH online, self-administered Clinical Trials Survey System. Minimum value = 0, maximum value = 160. Higher scores represent a better outcome/ better QOL.
  24. Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) Trial Outcome Index [ Time Frame: 12 months ] - Participants were asked to complete the FACIT-F questionnaire through the NIH online, self-administered Clinical Trials Survey System. The Trial Outcome Index (TOI) is the sum of the physical well-being, functional well-being and 'additional concerns' subscales. The minimum value = 0, and maximum value = 52. Scores under 30 is considered to be severe fatigue. Higher scores represent a better outcome/QOL.
  25. Pediatric Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) Total Score [ Time Frame: 12 months ] - Pediatric participants (< 18 years) were asked to complete the Peds-FACIT-F questionnaire through the NIH online, self-administered Clinical Trials Survey System.Minimum value = 0, maximum value = 52. Higher scores represent a better outcome/ better QOL.
  26. Blood Glutathione Reduced (GSH):Oxidized (GSSG) Ratio [ Time Frame: Baseline ] - GSH:GSSG ratio analyzed only at baseline to offer comparison of RYR1-RM affected individuals to the general population.
Eligibility: 

Ages Eligible for Study: 7 Years and older (Child, Adult, Older Adult)

Sexes Eligible for Study: All

Accepts Healthy Volunteers: Yes

Inclusion Criteria: 

None Indicated

Exclusion Criteria: 
  • EXCLUSION CRITERIA - HEALTHY VOLUNTEERS:​​
  • 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.

     
  • EXCLUSION CRITERIA - PATIENTS:
  • 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.
Study Site(s)/Location(s): 

United States, Maryland

National Institutes of Health Clinical Center

9000 Rockville Pike    

Bethesda, Maryland, 20892

Sponsors & Collaborators: 

National Institute of Nursing Research (NINR)

Principal Investigator(s): 

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

National Institute of Nursing Research (NINR)

ClinicalTrials.gov ID: 
NCT02362425