Results From 10-Patient Case Study Lead to Phase III Clinical Trial for Patients with Duchenne Muscular Dystrophy
Cedars-Sinai Heart Institute researchers have found that a commonly prescribed drug restores blood flow to oxygen-starved muscles of boys with
Duchenne muscular dystrophy, a genetic muscle-wasting disease that rarely is seen in girls but affects one in 3,500 male babies, profoundly shortening life expectancy. It is the most common fatal disease that affects children.
Muscle weakness begins in early childhood, often causing deformity of the arms, legs and spine. Heart and respiratory muscles often begin to fail before children reach early teen years. Although steroid medications – which often are not well tolerated – and other therapies may ease symptoms and delay the most severe effects, no disease-specific treatment exists, and patients rarely survive into their 30s.
But in this case study of 10 boys with Duchenne muscular dystrophy, also called DMD, a single dose of a drug often prescribed for erectile dysfunction or pulmonary hypertension corrected defective blood vessel mechanisms and restored blood flow to exercising muscles.
“The effects were immediate and dramatic, raising the question: If a single dose restores blood flow to muscle while the drug is in the patient’s system, could ongoing tadalafil administration provide sustained benefits, possibly preserve muscle and slow disease progression? If so, this would offer a new therapeutic strategy for DMD, and we have launched a randomized Phase III clinical trial to find out,” said Ronald Victor, MD, director of the Cedars-Sinai Center for Hypertension, associate director of clinical research at the Heart Institute and the Burns and Allen Chair in Cardiology Research. He is the senior author of a highlighted article in the May 7 online edition of Neurology.
Duchenne muscular dystrophy results from a genetic defect that eliminates a protein called dystrophin in the membranes of muscle cells. For more than 25 years, Victor has studied DMD and a less aggressive but debilitating variant called Becker muscular dystrophy. This form of muscular dystrophy, usually diagnosed in early adulthood, is caused by a reduction, but not absence, of dystrophin.
Victor led a research team that in 2000 discovered that the blood flow abnormality in the muscles of children with DMD was caused by a loss of nitric oxide, a signaling chemical that normally tells blood vessels to relax during exercise, increasing blood flow and oxygenation.
In studies of mice bred to represent diseases of dystrophin deficiency, the researchers found that drugs prescribed for other disorders of blood vessel function could restore muscle blood flow and enable the animals to exercise more, with less muscle injury. Tadalafil, known by the brand names Cialis and Adcirca, and sildenafil, called Viagra and Revatio, have long been approved by the Food and Drug Administration to treat erectile dysfunction and pulmonary hypertension, a serious illness that restricts blood flow to the lungs.
Translating these findings to a human clinical trial, Victor and his colleagues published in 2012 a study showing that tadalafil fully restored blood flow in eight of nine patients with Becker muscular dystrophy.
In the new study, investigators found that when boys with Duchenne muscular dystrophy performed handgrip exercises, the major artery of the arm and the blood vessels in muscles of the forearm failed to respond the way they did in healthy boys of similar ages, 8 to 13. But when the boys with DMD were given a single dose of tadalafil, normal vessel function and blood flow were restored. Similar results occurred when sildenafil, a drug with a similar mechanism of action on vessels but a different chemical structure, was used in place of tadalafil.
“Steroids and cardiac-protective blood pressure medication are increasingly prescribed at early ages for patients with Duchenne muscular dystrophy in an effort to delay by a few years the most devastating effects of the disease. But these treatments have no effect on the blood vessel dysfunction that prevents muscles from getting the oxygen they need,” said Victor. “In contrast, in our study, a single dose of tadalafil or sildenafil had an immediate effect. These are well-studied, well-tolerated drugs that are already on the market. If additional study confirms their benefits, repurposing the drugs for muscular dystrophy patients could quickly transform clinical practice.”
The Latest on: Duchenne muscular dystrophy
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The Latest on: Duchenne muscular dystrophy
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An new type of muscular dystrophy that's caused by inherited mutations in the SNUPN gene results in symptoms of muscle weakness before age 2.
- 'Time is against us': Half-marathon closing Route 9 to fund desperately needed drug trialon April 30, 2024 at 4:02 am
Jamesy Raffone is 15 and lives with Duchenne muscular dystrophy, which could take his life within 10 years. That's why this Route 9 race is important.
- Virtual Reality and Biofeedback Training Appear Effective for DMD, BMD Rehabilitationon April 29, 2024 at 11:57 am
A recent study suggests virtual reality and biofeedback training may be feasible and effective for patients with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD).
- Parent Project Muscular Dystrophy Awards $250,000 to Support Clinical Research Network for Duchenne Babies Identified by Newborn Screeningon April 29, 2024 at 6:59 am
Parent Project Muscular Dystrophy (PPMD), a nonprofit organization leading the fight to end Duchenne muscular dystrophy (Duchenne), is excited to announce a $250,000 award to Bo Hoon Lee, MD, from the ...
- Duchenne Muscular Dystrophy: the global clinical trials landscape 2024on April 29, 2024 at 4:02 am
Affecting muscle and skeletal strength, this rare genetic disorder impacts thousands of men worldwide. Innovative new genetic therapies in development across the globe are improving the quality of ...
- Patients With DMD Receiving Eteplirsen Show Prolonged Survival, Study Findson April 25, 2024 at 2:03 pm
The study provides evidence of survival benefits among patients with Duchenne muscular dystrophy (DMD) receiving eteplirsen compared with the natural history of the condition.
- DeWine: Ohio first state in the nation to screen newborn babies for Duchenne Muscular Dystrophyon April 24, 2024 at 9:00 pm
Ohio Gov. Mike DeWine on Monday announced that Ohio will become the first state in the nation to begin screening all newborn babies for Duchenne Muscular Dystrophy. The provision was included in HR 33 ...
- Ohio sets the trend in screening newborns for rare disease. What to know about DMDon April 24, 2024 at 3:58 am
Ohio Gov. Mike DeWine announced the state will be the first in the nation to screen newborns for the rare disease Duchenne Muscular Dystrophy.
- Capricor Therapeutics Announces Positive Type-B Meeting with FDA for CAP-1002 Program for Duchenne Muscular Dystrophyon April 24, 2024 at 1:59 am
Manufacturing and Controls (“CMC”) meeting with the U.S. Food and Drug Administration (“FDA”) on next steps for the Biologics License Application (“BLA”) submission with its lead asset CAP-1002 in ...
- My son's smile gives me hope for Duchenne muscular dystrophy. A new law could help otherson April 23, 2024 at 5:01 am
Opinion: Newborn testing can give families a head start on giving a child with the degenerative muscular disease a shot at the best outcome in life.
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