Trial of Tadalafil in DMD Open to Participants

Pharmaceutical company Eli Lilly is conducting a trial of tadalafil, which may help regulate blood flow to muscles, in some 300 boys with Duchenne MD

Article Highlights:
  • Drugs such as tadalafil and sildenafil, on the market for indications other than muscular dystrophy, may help overcome some blood-flow abnormalities in Becker and Duchenne muscular dystrophies.
  • Tadalafil is being tested in Becker MD and will now be tested in Duchenne MD.
  • Participants who meet study criteria are being invited to participate at 22 U.S. sites and additional worldwide locations.
by Margaret Wahl on December 11, 2013 - 11:18am

Multinational pharmaceutical company Eli Lilly is conducting a phase 3 trial of the drug tadalafil in approximately 300 boys with Duchenne muscular dystrophy (DMD) who are 7-14 years old, able to walk, have adequate cardiac function and meet other study criteria.

The rationale for using tadalafil to treat DMD or the related Becker muscular dystrophy (BMD) is that blood flow to exercising muscles appears to be disrupted in these disorders as a downstream effect of any of several mutations in the gene for the muscle protein dystrophin.

Drugs such as tadalafil and sildenafil (Viagra) are known to prolong the action of a substance called nitric oxide, and in so doing, may improve blood flow to exercising muscles despite the presence of dystrophin gene mutations that cause DMD and BMD. MDA has supported research in this area previously and continues to do so (see Joseph Beavo's Winter 2013 grant).

Tadalafil is being studied in patients with BMD at Cedars-Sinai Medical Center in Los Angeles.

Under the Eli Lilly brand name Cialis, tadalafil is on the market for erectile dysfunction and a type of prostate gland enlargement. Under the Eli Lilly brand name Adcirca, tadalafil is available for the treatment of pulmonary arterial hypertension.

Patients with DMD or BMD are advised not to seek an off-label prescription for tadalafil, as its effects and safety in these disorders is not yet well understood. ("Off label" refers to a physician's use of a drug or therapy to treat conditions other than the ones for which it received U.S. Food and Drug Administration approval.)

About the tadalafil in DMD study

The Lilly-sponsored study will determine whether orally administered tadalafil can slow the decline in walking ability in boys with DMD and will also assess the safety of tadalafil and any side effects that might be associated with it in DMD-affected boys.

Participants will be randomly assigned to receive tadalafil at one of two daily dosage levels or to receive a placebo for the first 48 weeks of the study. Participants will then have an option to move into a 48-week extension period during which everyone will receive tadalafil.

There are more than 60 study sites, including 22 in the United States, as well as locations in Argentina, Belgium, Canada, France, Germany, Italy, Japan, Korea, the Netherlands, Puerto Rico, the Russian Federation, Spain, Taiwan, Turkey and the United Kingdom.

Prospective participants must:

  • have a confirmed diagnosis of DMD;
  • be 7-14 years old;
  • be able to walk;
  • have been taking a corticosteroid drug (such as prednisone) for at least six months prior to screening for the study and have been on a stable dose for at least three months prior to screening;
  • be able to complete two "six-minute walk tests" (which measure the distance walked in six minutes) with results within 20 percent of each other;
  • have a left ventricular ejection fraction (a cardiac function measurement) of at least 50 percent as determined by an echocardiogram; and
  • provide informed consent (from parents or guardians) and assent (from participants).

Prospective participants must not:

  • have symptoms of cardiomyopathy (cardiac muscle degeneration) or heart failure;
  • have had a change in preventive treatment for heart failure within three months of the start of the study;
  • have a cardiac rhythm disorder;
  • have participated in a trial of gene- or cell-based therapy, antisense oligonucleotides, or stop codon read-through therapy;
  • be unable to take oral tablets;
  • have used any drug treatment other than corticosteroids that might have an effect on muscle strength within three months of the start of the study;
  • make a change in or start a new herbal or dietary supplement with an expectation of an effect on muscle strength or function during the month prior to the first dose of the study drug;
  • have had surgery that might have an effect on muscle strength or function within three months prior to study entry or have surgery planned during the study period;
  • have a leg injury that might affect performance on the six-minute walk test;
  • have severe behavioral problems that might interfere with completion of the six-minute walk test;
  • have any contraindication to tadalafil;
  • have significant kidney or liver abnormalities;
  • have a known allergy to any of the ingredients (such as lactose) of tadalafil tablets; or
  • be taking a phosphodiesterase type 5 (PDE5) inhibitor or have received one within the past six months.

To participate

For details and contact information, see A Study of Tadalafil for Duchenne Muscular Dystrophy; or enter NCT01865084 in the search box at You also can call Eli Lilly toll-free at (877) 285-4559 Monday through Friday, 9 a.m. to 5 p.m. Eastern time.

And to learn more, read Enhancing Blood Flow to Exercising Muscles (April 2011).

About Clinical Trials

About Clinical Trials

A clinical trial is a test, in humans, of an experimental treatment. Although it's possible that benefit may be derived from participating in a clinical trial, it's also possible that no benefit, or even harm, may occur.

MDA has no ability to influence who is chosen to participate in a clinical trial.

To learn more about clinical trials, see Being a Co-Adventurer. For a more refined list of clinical trials, visit, a registry of federally and privately supported clinical trials in the United States and around the world. Select the "Find Studies" tab, and follow the instructions to narrow down your search results.

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