The purpose of this study is to compare Dichlorphenamide with placebo (an inactive substance) for prevention of episodes and for improvement of strength in hyperkalemic (HYP) and hypokalemic (HOP) periodic paralysis. This study will also look at the long-term effects of Dichlorphenamide in periodic paralysis.
Periodic paralysis is a relatively rare, life-long disorder characterized by intermittent bouts of paralysis, progressive weakness, and diminished quality of life. Two drugs, acetazolamide (ACZ) and dichlorphenamide, have been prescribed to treat the disorder, however, dichlorphenamide is no longer available. In this multi-center, parallel, randomized trial researchers will compare the effects of dichlorphenamide vs. placebo in patients with hyperkalemic (HYP) and hypokalemic (HOP) periodic paralysis. The trial consists of two 9-week studies-one study will enroll persons with hyperkalemic periodic paralysis and the other study will enroll persons with hypokalemic periodic paralysis. Participants will be randomly assigned to one of two treatment groups: dichlorphenamide or placebo (an inactive substance). During the studies, participants will be asked to keep a daily diary to record the time, length, and severity of each episode of weakness (attack). The study coordinator will contact participants weekly to review the diary information. The 9-week phase will be followed by a 1-year open-label dichlorphenamide extension without placebo to determine the long-term effects of dichlorphenamide on the course of the disease and on inter-attack weakness. Duration of the trial for participants is approximately 65 weeks, including a screening phase to determine eligibility, the first 9-week treatment phase, and the one-year open-label extension phase.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
71
50mg tablet; maximum dosage 400mg/day
Inactive substance manufactured to look like Dichlorphenamide 50mg tablet
50mg tablet; maximum dosage 400mg/day
UCLA Neurology
Los Angeles, California, United States
University of California-San Francisco
San Francisco, California, United States
University of Kansas Medical Center
Kansas City, Kansas, United States
HYP Attack Rate
The number of distinct attacks per week over the final 8 weeks (Weeks 2-9) of the double-blind treatment period as self-reported by HYP participants.
Time frame: 8 weeks
HOP Attack Rate
The number of distinct attacks per week over the final 8 weeks (Weeks 2-9) of the double-blind treatment period as self-reported by HOP participants.
Time frame: 8 weeks
HYP Severity-weighted Attack Rate
HYP participant severity-weighted attack rate is defined as the sum of average attack severity across all distinct attacks over the final 8 weeks (Weeks 2-9) of the double-blind treatment period divided by the number of weeks that the subject was followed. Attack severity (scored as 1-10 with increasing severity) is self-reported.
Time frame: 8 weeks
HOP Severity-weighted Attack Rate
HOP participant severity-weighted attack rate is defined as the sum of average attack severity across all distinct attacks over the final 8 weeks (Weeks 2-9) of the double-blind treatment period divided by the number of weeks that the subject was followed. Attack severity (scored as 1-10 with increasing severity) is self-reported.
Time frame: 8 weeks
HYP Attack Duration
HYP participant total attack duration per week, defined as the sum of attack durations across all distinct attacks over the final 8 weeks (Weeks 2-9) of the double-blind treatment period divided by the number of weeks that the subject was followed.
Time frame: 8 weeks
HOP Attack Duration
HOP participant total attack duration per week, defined as the sum of attack durations across all distinct attacks over the final 8 weeks (Weeks 2-9) of the double-blind treatment period divided by the number of weeks that the subject was followed.
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Brigham & Women's Hospital
Boston, Massachusetts, United States
Mayo Clinic
Rochester, Minnesota, United States
Washington University School of Medicine
St Louis, Missouri, United States
Columbia University Medical Center
New York, New York, United States
University of Rochester
Rochester, New York, United States
Ohio State University
Columbus, Ohio, United States
University of Texas Southwestern-Dallas
Dallas, Texas, United States
...and 2 more locations
Time frame: 8 weeks
HYP Endpoint of Acute Worsening
Increase in attack frequency or severity in HYP participants necessitating withdrawal from the initial nine-week double-blind treatment period and moving directly into the open-label phase.
Time frame: 0-9 weeks
HOP Endpoint of Acute Worsening
Increase in attack frequency or severity in HOP participants necessitating withdrawal from the initial nine-week double-blind treatment period and moving directly into the open-label phase.
Time frame: 0-9 weeks
HYP Change From Baseline to Week 9 in Average Manual Muscle Testing (MMT) Score
The strength of each of 26 individual muscles was graded using a modified 13-point Medical Research Council scale ranging from 0-5. Recorded grades were converted to numerical values as follows prior to averaging across muscles to form a composite score: 0 = 0; 1 = 1; 2- = 1.67; 2 = 2; 2+ = 2.33; 3- = 2.67; 3 = 3; 3+ = 3.33; 4- = 3.67; 4 = 4; 4+ = 4.33; 5- = 4.67; 5 = 5. A higher score represents a better outcome, i.e. 5 = normal strength. The following muscles were tested: shoulder abductor (left/right), elbow extensor (left/right), elbow flexor (left/right), wrist extensor (left/right), wrist flexor (left/right), hip flexor (left/right), hip extensor (left/right), hip abductor (left/right), knee extensor (left/right), knee flexor (left/right), ankle dorsiflexor (left/right), ankle plantar flexor (left/right), neck extensor, neck flexor.
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in Average Manual Muscle Testing (MMT) Score
The strength of each of 26 individual muscles was graded using a modified 13-point Medical Research Council scale ranging from 0-5. Recorded grades were converted to numerical values as follows prior to averaging across muscles to form a composite score: 0 = 0; 1 = 1; 2- = 1.67; 2 = 2; 2+ = 2.33; 3- = 2.67; 3 = 3; 3+ = 3.33; 4- = 3.67; 4 = 4; 4+ = 4.33; 5- = 4.67; 5 = 5. A higher score represents a better outcome, i.e. 5 = normal strength. The following muscles were tested: shoulder abductor (left/right), elbow extensor (left/right), elbow flexor (left/right), wrist extensor (left/right), wrist flexor (left/right), hip flexor (left/right), hip extensor (left/right), hip abductor (left/right), knee extensor (left/right), knee flexor (left/right), ankle dorsiflexor (left/right), ankle plantar flexor (left/right), neck extensor, neck flexor.
Time frame: Baseline and 9 weeks
HYP Change From Baseline to Week 9 in Average Maximum Voluntary Isometric Contraction Testing (MVICT) Scores
The strength of each of 10 muscles was measured using quantitative myometry and expressed as the number of standard deviations from normal (Z-score) given the participant's age, gender, and height. The scores were averaged across muscles to form a composite MVICT score: average standardized MVICT score. A positive Z-score indicates a better outcome. The following muscles were tested: elbow extensor (left/right), elbow flexor (left/right), knee extensor (left/right), knee flexor (left/right), and hand grip (left/right).
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in Average Maximum Voluntary Isometric Contraction Testing (MVICT) Scores
The strength of each of 10 muscles was measured using quantitative myometry and expressed as the number of standard deviations from normal (Z-score) given the participant's age, gender, and height. The scores were averaged across muscles to form a composite MVICT score: average standardized MVICT score. A positive Z-score indicates a better outcome. The following muscles were tested: elbow extensor (left/right), elbow flexor (left/right), knee extensor (left/right), knee flexor (left/right), and hand grip (left/right).
Time frame: Baseline and 9 weeks
HYP Change From Baseline to Week 9 in Average Maximum Voluntary Isometric Contraction Testing Percent of Predicted Normal
The strength of each of 10 muscles was measured using quantitative myometry and expressed as the percent of predicted normal given the participant's age, gender, and height. The scores were averaged across muscles to form a composite MVICT score: average percent of predicted normal score. A higher number indicates a better outcome. The following muscles were tested: elbow extensor (left/right), elbow flexor (left/right), knee extensor (left/right), knee flexor (left/right), and hand grip (left/right).
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in Average Maximum Voluntary Isometric Contraction Testing Percent of Predicted Normal
The strength of each of 10 muscles was measured using quantitative myometry and expressed as the percent of predicted normal given the participant's age, gender, and height. The scores were averaged across muscles to form a composite MVICT score: average percent of predicted normal score. A higher number indicates a better outcome. The following muscles were tested: elbow extensor (left/right), elbow flexor (left/right), knee extensor (left/right), knee flexor (left/right), and hand grip (left/right).
Time frame: Baseline and 9 weeks
HYP Change From Baseline to Week 9 in Lean Body Mass
Lean body mass was measured by dual-energy X-ray absorptiometry (DEXA).
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in Lean Body Mass
Lean body mass was measured by dual-energy X-ray absorptiometry (DEXA).
Time frame: Baseline and 9 weeks
HYP Change From Baseline to Week 9 in SF-36 Physical Component Summary Score
The Medical Outcomes Study Short Form (SF-36) questionnaire is a widely used profile measure of generic health-related quality of life. The 36 questions are allocated to eight scales: physical function (PF), physical role (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social function (SF), mental health (MH), and emotional role (RE). The physical component summary score is calculated from the four scales of PF, RP,BP, and GH. Scores are constructed as a T-score with a mean of 50 and standard deviation of 10 and no minimum or maximum score. Higher scores are associated with better quality of life.
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in SF-36 Physical Component Summary Score
The Medical Outcomes Study Short Form (SF-36) questionnaire is a widely used profile measure of generic health-related quality of life. The 36 questions are allocated to eight scales: physical function (PF), physical role (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social function (SF), mental health (MH), and emotional role (RE). The physical component summary score is calculated from the four scales of PF, RP, BP, and GH. Scores are constructed as a T-score with a mean of 50 and standard deviation of 10 and no minimum or maximum score. Higher scores are associated with better quality of life.
Time frame: Baseline and 9 weeks
HYP Change From Baseline to Week 9 in SF-36 Mental Health Component Summary Score
The Medical Outcomes Study Short Form (SF-36) questionnaire is a widely used profile measure of generic health-related quality of life. The 36 questions are allocated to eight scales: physical function (PF), physical role (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social function (SF), mental health (MH), and emotional role (RE). The mental health component summary score is calculated from the four scales of VT, SF, MH, and RE. Scores are constructed as a T-score with a mean of 50 and standard deviation of 10 and no minimum or maximum score. Higher scores are associated with better quality of life.
Time frame: Baseline and 9 weeks
HOP Change From Baseline to Week 9 in SF-36 Mental Health Component Summary Score
The Medical Outcomes Study Short Form (SF-36) questionnaire is a widely used profile measure of generic health-related quality of life. The 36 questions are allocated to eight scales: physical function (PF), physical role (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social function (SF), mental health (MH), and emotional role (RE). The mental health component summary score is calculated from the four scales of VT, SF, MH, and RE. Scores are constructed as a T-score with a mean of 50 and standard deviation of 10 and no minimum or maximum score. Higher scores are associated with better quality of life.
Time frame: Baseline and 9 weeks