Acceleron Pharma announced positive preliminary results for the first two cohorts in Part 1 of the Phase 2 clinical trial with ACE-083 in patients with facioscapulohumeral dystrophy (FSHD), a rare genetic muscle disorder that results in progressive focal muscle loss and weakness. The company plans to initiate Part 2 of the ACE-083 FSHD Phase 2 trial during the second quarter of 2018.
“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,” said Matthew Sherman, M.D., Chief Medical Officer of Acceleron. “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 Phase 2 trial is an open-label, dose-escalation study of ACE-083 designed to evaluate safety as well as changes in total muscle volume in up to 36 patients with FSHD. Preliminary results include data from 23 patients evaluable for magnetic resonance imaging (MRI) among two different cohorts (11 patients with tibialis anterior weakness and 12 patients with biceps brachii weakness). Each patient received ACE-083 (150 mg or 200 mg) as a unilateral intramuscular injection once every three weeks for 12 weeks. Total muscle volume changes were measured by MRI relative to baseline at 3 weeks after the last injection of ACE-083. Based on overlap in dosing on a milligram per gram muscle analysis, dose cohorts were pooled for the analyses of each muscle.
ACE-083 is a therapeutic candidate, based on the naturally-occurring protein follistatin, which utilizes the “Myostatin+” approach to inhibit multiple TGF-beta ligands. It is designed to have a concentrated effect along targeted muscles to maximize growth and strength selectively in the muscles into which the drug is administered. Acceleron is developing ACE-083 for diseases such as facioscapulohumeral dystrophy (FSHD) and Charcot-Marie-Tooth (CMT) disease, in which improved muscle strength in target muscles may provide a clinical benefit and enhance quality of life.
FSHD is a rare genetic muscle disorder affecting approximately 20,000 people in the United States for which there are currently no approved treatments. The primary clinical presentation of FSHD is debilitating skeletal muscle weakness and loss. The symptoms of FSHD develop in a descending pattern, beginning with the face and upper body and progressing to the lower body in a "muscle by muscle" fashion. The disease is typically diagnosed by a characteristic pattern of muscle weakness and other clinical symptoms, as well as through genetic testing.