Tadalafil And Sildenafil Show Efficacy In Duchenne Muscular Dystrophy

Researchers at the Cedars-Sinai Heart Institute discovered that two commonly prescribed drugs for erectile dysfunction and pulmonary hypertension showed promising efficacy in patients with Duchenne muscular dystrophy (DMD).

Duchenne muscular dystrophy is a genetic muscle-wasting disease rarely seen in girls but affects one in 3,500 baby boys. The disease is among the most common fatal disease in children. DMD causes progressive failure in heart and respiratory muscles before children reach early teens. The disease also causes deformity in the legs, arms, and spine. No specific treatment for DMD has been established, though steroid medications are often used to ease symptoms and delay the most severe effects. Patients with DMD rarely survive into their 30s.

In a case study of 10 boys with DMD, researchers found that a single dose of tadalafil restored defective blood vessel mechanisms and blood flow to exercising muscles. Similar effects were observed when sildenafil, which has a similar mechanism of action but different chemical structure, was used. Tadalafil is known by brand names Cialis and Adcirca, while sildenafil is marketed under brand names Viagra and Revation. The drugs have been approved by the U.S. Food and Drug Administration (FDA) to treat erectile dysfunction and pulmonary hypertension.

“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. 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.” said Ronald Victor, 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.

Victor said that he and his team have launched a randomized Phase III clinical trial to further investigate the effects of ongoing tadalafil administration as a new therapeutic strategy for DMD.