Tadalafil and Sildenafil for Duchenne Muscular Dystrophy
This study, supported by Parent Project Muscular Dystrophy, will determine if tadalafil or sildenafil can improve muscle blood flow during exercise in boys with Duchenne muscular dystrophy.
|Study Design:||Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Functional Muscle Ischemia and PDE5A Inhibition in Duchenne Muscular Dystrophy|
- Functional muscle ischemia [ Time Frame: For 5 study visits ] [ Designated as safety issue: No ]Measured by the decrease in muscle tissue oxygenation (near infrared spectroscopy) and blood flow (Doppler ultrasound) evoked by reflex sympathetic activation in exercising forearm muscle.
- Cardiac Function [ Time Frame: For 5 study visits ] [ Designated as safety issue: No ]Echocardiogram
- EKG Monitoring [ Time Frame: 5 times over about 6 weeks ] [ Designated as safety issue: Yes ]48 hour Holter monitoring
- 6 Minute Walk Test [ Time Frame: For 5 study visits ] [ Designated as safety issue: No ]
- Physical Activity [ Time Frame: 5 times over about 6-weeks ] [ Designated as safety issue: No ]Assessed by accelerometers
- Quality of Life [ Time Frame: For 5 study visits ] [ Designated as safety issue: No ]PedsQL inventory
|Study Start Date:||May 2011|
|Study Completion Date:||May 2013|
|Primary Completion Date:||May 2013 (Final data collection date for primary outcome measure)|
Escalating dose (0.25 mg/kg, 0.5 mg/kg, 1.0 mg/kg; once daily) over 2 weeks
Escalating dose (0.25 mg/kg, 0.5 mg/kg, 1.0 mg/kg; four times daily) over 2 weeks
Duchenne muscular dystrophy (DMD) is a rare, progressive and fatal muscle disease affecting boys and accounts for 80% of muscular dystrophy cases. Tadalafil and sildenafil are medications approved by the FDA for the treatment of erectile dysfunction and pulmonary hypertension. This class of medication improves muscle blood flow in a mouse model of muscular dystrophy, but their benefit to boys with DMD is unknown. The purpose of this study is to 1) determine if tadalafil or sildenafil can improve muscle blood flow during exercise in boys with DMD; and 2) to inform the design of a subsequent, randomized, multi-center trial with clinical endpoints.
The investigators will enroll boys with DMD between the ages of 7 and 15 years who are ambulatory and without clinical heart failure. Participants will undergo 6 visits over the course of 5 weeks. The initial visit will include a medical history, physical exam, echocardiogram, and blood draw to determine eligibility for the study. Boys will be given a Holter monitor (a heart monitor) to wear for 48 hours to observe any irregular heartbeats or abnormalities.
Eligible boys will be randomized to one of the two study drugs: tadalafil or sildenafil. The boys will take a low dose (0.25mg/kg) of the study drug for the first 2 days and an intermediate dose (0.5mg/kg) for the subsequent 5 days. Then, boys will take a higher dose (1.0mg/kg) of the study drug for 1 week. Tadalafil will be taken once daily and sildenafil will be taken four times daily.
Study visits will occur 2 times at baseline, 2 times during the medication, and 1 time after washout of the medication. For these visits, boys will undergo an arm blood flow and hand grip exercise protocol. In this procedure, blood flow and oxygen delivery to the forearm muscles will be measured (noninvasively) before and during application of lower body negative pressure at rest and during handgrip exercise. Lower body negative pressure stimulates the blood flow changes that normally occur when a person sits up after lying down. During these visits, boys will complete a quality of life questionnaire, echocardiogram, and 6-minute walk tests. At home, boys will wear an accelerometer to measure physical activity and a Holter monitor to check for irregular heartbeats.
For boys who wish to continue with the study, there will be an option to cross-over and complete study visits with the drug they did not originally receive.
|United States, California|
|Cedars-Sinai Medical Center|
|Los Angeles, California, United States, 90048|
|Principal Investigator:||Ronald Victor, MD||Cedars-Sinai Medical Center|