Tafalafil known as the brand name drugs Cialis and Adcirca,may offer new treatment
Becker’s muscular dystrophy (Benign pseudohypertrophic muscular dystrophy) is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis. This dystrophy is very similar to Duchenne muscular dystrophy with the exception of becoming worse at a much slower rate. Becker affects males, and symptoms begin to appear between the ages of 2 and 16. Sufferers of Becker experience walking difficulty by early adulthood. On average, males with Becker dystrophy are confined to a wheelchair by the age of 35. Unlike Duchenne dystrophy, males living with Becker generally live a long life.
There is no known cure for Beck muscular dystrophy and treatments given are to control the symptoms to maximize the patient’s quality of life.
Researchers from Cedars-Sinai now may be able to provide a new way of drug treatment through the drug Tadalafil known as Cialis used to treat erectile dysfunction and Adcirca used to treat pulmonary arterial hypertension.
Dr. Ronald G. Victor, MD, Director of the Cedars-Sinai Center for Hypertension, Associate Director of Clinical Research and holds the Burns and Allen Chair in Cardiology Research at the Cedars-Sinai Heart Institute and senior author of this new study who previously led a research team that had discovered blood flow abnormality from loss of nitric oxide in the muscles of children with Duchenne muscular dystrophy.
This new study demonstrates that the blood flow problem present in children is also common in adults with Becker muscular dystrophy, by which giving improved blood circulation as a possible way for treatment.
In this double-blind, randomized cross-over trial patients forearm muscle oxygenation levels measured while performing hand grip exercises. Patients had either received one 20mg capsule of tafalafil or a placebo in which directly after the dosage patients were evaluated. A two week break was then give to the patients to make sure the drug had left their systems and then the two groups were switched.
The results showed that the single dose of the drug in which works downstream from nitric oxide had fully reinstated proper blood flow in eight of the nine patients. The effects were noted as “immediate” both times.
The dosage of the drug used in this study which was one-half dose has FDA approval for tafalafil to be used daily in the treatment of pulmonary hypertension.
The drug works by reversing the effects of a biochemical chain of events that in Becker muscular dystrophy deprives muscles of an important chemical, nitric oxide, which normally tells blood vessels to relax during exercise, increasing blood flow and oxygenation.
Dr. Victor states “this is the first study showing that the drug may offer a therapeutic strategy in humans.” He also adds that the blood flow effects in this single-dose trial were dramatic and encouraging but more research is needed before recommending tadalafil for patients with Becker muscular dystrophy.
In closing Dr. Victor says “Cedars-Sinai is planning longer term studies to determine if correcting muscle blood flow leads to a clinically meaningful outcome.” “This is not a cure, but it could be the first step toward identifying potential treatments for Becker muscular dystrophy. Providing adequate oxygenation to muscles already weakened by abnormal dystrophin may be a strategy to slow the course of the disease. Tadalafil already is a well-studied and well-known medication that enjoys a very favorable side-effect profile. Since no new drug development would be needed, repurposing it for muscular dystrophy could quickly transform clinical practice.”
This study appears in the journal Science Translational Medicine.
The study was funded by research grants from the Muscular Dystrophy Association and the National Center for Advancing Translational Sciences.