Pfizer Inc. announced enrollment of the first patient in a multicentre phase II clinical trial of the investigational compound PF-06252616 in boys with Duchenne muscular dystrophy (DMD), a genetic disorder characterised by progressive muscle degeneration and weakness. PF-06252616 is an experimental, infused, anti-myostatin monoclonal antibody. Myostatin is a naturally occurring protein in muscles that helps control muscle growth; it is believed that blocking the activity of myostatin may have potential therapeutic application in treating muscle wasting diseases such as DMD.

“DMD is a devastating and debilitating disease impacting approximately 1 in 3,500 male births worldwidei with no current treatment options,” said Kevin Lee, senior vice president and chief scientific officer of Pfizer’s Rare Disease Research Unit. “We are pleased to be taking this important next step in the development of PF-06252616 as an investigational therapy for DMD in the hopes of potentially bringing a much-needed therapy to individuals and families with this devastating disease.”

The phase 2 clinical trial will evaluate the safety, tolerability and efficacy of PF-06252616 in boys aged 6 to <10 years old diagnosed with DMD regardless of genotype. Based on the proposed mechanism of action of PF-06252616, Pfizer is exploring whether there is the potential to increase muscle mass and function in boys with DMD who are weak and have lost muscle.

“We are enthusiastic about the potential for myostatin inhibitors to stimulate increases in muscle mass and strength for people living with Duchenne muscular dystrophy. This approach could potentially add an important angle in our fight against this disease and we are pleased to see the time and great care that Pfizer has expended on its development,” said Dr. Sharon Hesterlee, vice president of Research for Parent Project Muscular Dystrophy (PPMD). “Our Duchenne community is proud to have the extraordinary passion and expertise of the Pfizer team fighting with us.”

PF-06252616 was granted Orphan Drug designation in July 2012 and Fast Track Designation in November 2012 by the US Food and Drug Administration (US FDA). The FDA’s Fast Track Designation is a process designed to facilitate the development and expedite the review of new drugs and biologics intended to treat or prevent serious conditions and that address an unmet medical need.ii The European Medicines Agency (EMA) granted the investigational candidate Orphan Medical Product designation in February 2013.

Duchenne muscular dystrophy (DMD) is a genetic disorder characterised by progressive muscle degeneration and weakness. DMD is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. Symptom onset is in early childhood, usually between the ages of 3 and 5. The disease primarily affects boys, but in rare cases it can affect girls. Muscle weakness can begin as early as age 3, first affecting the muscles of the hips, pelvic area, thighs and shoulders, and later the skeletal (voluntary) muscles in the arms, legs and trunk. The calves often are enlarged. By the early teens, the heart and respiratory muscles are also affected.

Rare diseases are among the most serious of all illnesses and impact millions of patients worldwide, representing an opportunity to apply our knowledge and expertise to help make a significant impact in addressing unmet medical needs. The Pfizer focus on rare diseases builds on more than a decade of experience and a global portfolio of 22 medicines approved worldwide that treat rare diseases in the areas of hematology, neuroscience, inherited metabolic disorders, pulmonology, and oncology.