Healthy Volunteers Clinical Trials

Cedars-Sinai Heart Institute is currently conducting the following studies:

• Functional Muscle Ischemia and PDE5A Inhibition in Becker Muscular Dystrophy

Functional Muscle Ischemia and PDE5A Inhibition in Becker Muscular Dystrophy

Principal Investigator: Ronald Victor, MD

IRB Approval Number: 20477

Contact: Dominique Durant (310) 248-8080

Status: Enrolling

Summary: 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. 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 to be measured before and during application of lower body negative pressure at rest and during handgrip exercise. The results of the baseline study will determine which patients meet preset eligibility criteria to participate in the medication phase of the study.. Only eligible Becker Muscular Dystrophy subjects 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. 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