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Tadalafil in Becker Muscular Dystrophy

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01070511
Recruitment Status : Completed
First Posted : February 18, 2010
Last Update Posted : August 20, 2013
Muscular Dystrophy Association
Information provided by (Responsible Party):
Ron Victor, Cedars-Sinai Medical Center

Brief Summary:

Summary for Patients: This study, funded by the Muscular Dystrophy Association, is intended to build on recent findings published in the journal Nature showing beneficial effects of tadalafil (also known as Cialis) in mice with an animal version of Duchenne and Becker muscular dystrophies. Only two doses of tadalafil improved muscle blood flow, allowing the dystrophic mice to perform more exercise with less muscle injury. This new short-term clinical trial will move the testing from animals to human patients with Becker muscular dystrophy and examine the effects of acute tadalafil dosing on muscle blood flow during a bout of exercise. Patients will take two doses of tadalafil prior to exercising. Then doctors will measure whether muscles receive increased blood flow and therefore are better protected during exercise.

Scientific Hypothesis: In patients with Becker muscular dystrophy (particularly those with dystrophin gene mutations between exons 41-46), loss of sarcolemmal nitric oxide synthase engenders functional muscle ischemia and thus muscle edema after an acute bout of exercise. The investigators further hypothesize that PDE5A inhibition, which boosts nitric oxide-cGMP signaling, constitutes an effective new countermeasure for these patients.

Condition or disease Intervention/treatment Phase
Becker Muscular Dystrophy Drug: Tadalafil Drug: Placebo Phase 4

Detailed Description:

There are 2 phases to this research project: (1) an initial baseline study to compare patients with Becker muscular dystrophy against healthy control subjects, and (2) a subsequent brief treatment trial only in the muscular dystrophy patients (healthy controls will not participate in this second phase of the study).

The baseline study involves an intake history, physical examination, and phlebotomy for blood chemistries and DNA followed by (a) MRI scans of the forearm muscles before and after a brief bout of handgrip exercise approximately 1-1.5 hours to complete), and (b) non-invasive forearm blood flow studies (Near Infrared Spectroscopy, Doppler Ultrasound) before and after a brief bout of handgrip exercise (approximately 3-5 hours to complete). Blood flow studies will be performed with the subject's lower body enclosed in an airtight chamber. Blood flow and oxygen delivery to the forearm muscles will be measured before and during application of lower body negative pressure at rest and during handgrip exercise. Lower body negative pressure simulates the blood flow changes that normally occur when a person sits up after lying down.

The results of the baseline study will determine which patients meet preset eligibility criteria to participate in the medication phase of the study. These criteria include (1) normal kidney and liver function tests and normal BNP levels (the latter to exclude heart failure), and (2) abnormal MRI and blood flow responses to handgrip exercise. Eligible patients will be asked to repeat the above laboratory procedures on two more study days: one day after receiving 2 pills of tadalafil (a PDE5A inhibitor that is longer-lasting than Viagra) and another day after receiving 2 placebo pills. Study procedures can be broken up into two separate days for scheduling purposes and/or to avoid fatigue. Patients completing the trial will receive both study medications and the order will be random.

In summary, healthy control subjects will only undergo the baseline study whereas Becker muscular dystrophy patients completing all phases of the project will have 3 separate study days (baseline, tadalafil, and placebo) and 2 medication visits (to receive the study medication and have their blood pressure checked by a study physician). Study days will be separated by at least two weeks to allow time for test results, to rest the forearm muscles between exercise bouts, and to ensure complete elimination of tadalafil.

We plan to enroll 24 adult men with Becker muscular dystrophy, of whom 12 men will have dystrophin gene deletions between exons 41-46, and 24 healthy control subjects.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 48 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: Functional Muscle Ischemia and PDE5A Inhibition in Becker Muscular Dystrophy
Study Start Date : January 2010
Actual Primary Completion Date : December 2012
Actual Study Completion Date : December 2012

Arm Intervention/treatment
Experimental: Tadalafil Drug: Tadalafil
Tadalafil will be administered orally on two consecutive days. The first dose-10 mg- will be administered the afternoon before the study. The second dose -20 mg-will be administered the morning of the study.
Other Name: Cialis

Placebo Comparator: Placebo Drug: Placebo
A placebo pill will be administered orally on two consecutive days. The first pill will be administered the afternoon before the study. The second pill will be administered the morning of the study.

Primary Outcome Measures :
  1. Reflex decrease in muscle tissue oxygenation (i.e., adrenergic vasoconstriction) during rhythmic handgrip exercise measured by Near Infrared Spectroscopy (NIR). [ Time Frame: measured at a minimum of 2 week intervals for a minimum of 6 weeks total (for subjects with BMD) ]

Secondary Outcome Measures :
  1. Change in forearm muscle water content by magnetic resonance imaging (MRI). [ Time Frame: measured at a minimum of 2 week intervals for a minimum of 6 weeks total (for subjects with BMD) ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 55 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Becker Muscular Dystrophy Patients

  • Men 18-55 years of age with a pre-existing diagnosis of Becker Muscular Dystrophy by a clinical neurologist (based on clinical criteria plus previous muscle biopsy analysis and/or DNA analysis).

Healthy Controls

  • Men 18-55 years of age with no known medical conditions

Criteria for exclusion of subjects (both patients and controls)

  • Any evidence of cardiopulmonary disease by history or by physical examination
  • History of hypertension or blood pressure averaging ≥140/90 mmHg
  • Diabetes mellitus or other systemic illness
  • Heart failure by clinical exam, elevated BNP, or heart failure medication
  • Serum creatinine ≥ 1.5 mg/dL
  • Any history of substance abuse (including alcohol)
  • Any history of psychiatric illness
  • Contraindications to tadalafil (use of nitrates, alpha-blockers, other PDE5A inhibitors, or potent inhibitors of CYP3A4 such as ketoconazole or ritonavir)
  • Contraindications to MRI (claustrophobia, metal implants, or seizure disorder)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01070511

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United States, California
Cedars-Sinai Medical Center
Los Angeles, California, United States, 90048
Cedars Sinai Medical Center
Los Angeles, California, United States, 9004
Sponsors and Collaborators
Cedars-Sinai Medical Center
Muscular Dystrophy Association
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Principal Investigator: Ronald G Victor, MD Cedars-Sinai Medical Center
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Responsible Party: Ron Victor, Director Hypertension Center, Cedars-Sinai Medical Center Identifier: NCT01070511    
Obsolete Identifiers: NCT02207283, NCT03076814
Other Study ID Numbers: MDA 158944
First Posted: February 18, 2010    Key Record Dates
Last Update Posted: August 20, 2013
Last Verified: August 2013
Keywords provided by Ron Victor, Cedars-Sinai Medical Center:
Muscular Dystrophy
Additional relevant MeSH terms:
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Muscular Dystrophies
Muscular Dystrophy, Duchenne
Muscular Disorders, Atrophic
Muscular Diseases
Musculoskeletal Diseases
Neuromuscular Diseases
Nervous System Diseases
Genetic Diseases, Inborn
Genetic Diseases, X-Linked
Vasodilator Agents
Phosphodiesterase 5 Inhibitors
Phosphodiesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Urological Agents