Phase 2 of Potential FSHD Therapy Returns Positive Results

Acceleron Pharma has announced that Part 1 of the Phase 2 clinical trial of ACE-083, a drug used to increase muscle volume in facioscapulohumeral dystrophy (FSHD), has exhibited positive results.

FSHD, a rare genetic muscle disorder, causes progressive muscle weakness and wasting. Muscle atrophy most commonly begins around the face, shoulder blades, and upper arms, and eventually works its way down the body “muscle by muscle”. The disease affects 20,000 people in the United States and has no currently approved treatments. ACE-083 is based on the naturally-produced protein follistatin and is designed to concentrate growth and strength on selected muscles through drug administration.

“Preliminary results of ACE-083 in FSHD patients demonstrated positive safety and tolerability along with unprecedented mean increases in total muscle volume of over 12% in the two distinct muscles evaluated,” stated Matthew Sherman, M.D., Chief Medical Officer of Acceleron in a press release. “These data support our decision to advance to Part 2 of the Phase 2 trial, which we expect to initiate in the second quarter of this year. We look forward to fully exploring functional outcomes in the larger, placebo-controlled Part 2 of the trial.”

Part 1 of the study was designed to evaluate the safety of ACE-083 in FSHD patients. The drug was administered to each patient as a single-dose unilateral intramuscular injection every 3 weeks over a 12-week period, and the results accounted for 23 patients with magnetic resonance imaging (MRI) to evaluate their tolerability and muscle volume.

Two cohorts focused on different muscles located on different parts of the body: the tibialis anterior (TA) is in the lower leg and affects lifting the foot to take a step, and the biceps brachii (BB) allows the arm to bend at the elbow. 11 patients made up the TA cohort, leading to an average muscle volume increase of 12.6% after the 12-week period. The BB cohorts resulted in a mean muscle volume increase of 13.2%.

Dr. Jeffrey Statland, M.D., Associate Professor of Neurology at the University of Kansas Medical Center and the ACE-083 FSHD Phase 2 trial principal investigator is anticipating the next part of Phase 2: “I am encouraged by the preliminary safety and tolerability results of ACE-083 in Part 1 of the trial. There are currently no FDA approved therapies for FSHD, therefore limiting our treatment of patients to supportive options such as physical therapy and bracing. ACE-083 is demonstrating encouraging activity in its ability to increase muscle volume, and I look forward to its advancement in Part 2 of the trial.”

In addition to its intended use in FSHD, Acceleron is developing ACE-083 for Charcot-Marie-Tooth (CMT) disease, in which improved muscle strength in target muscles may provide a clinical benefit and enhance quality of life.

For more from within the rare disease community, follow Rare Disease Report on Facebook and Twitter.