Acceleron announce preliminary results from FSHD trial

Acceleron Pharmaceuticals has announced preliminary results from its phase 2 trial testing ACE-083 in adults with facioscapulohumeral muscular dystrophy (FSHD).

ACE-083 is a drug that inhibits a family of proteins that negatively regulate muscle growth (including myostatin). This approach aims to build muscle mass and improve muscle strength.

The trial is split into two parts:


  • Part 1 is a dose-escalation study. This was designed to identify the highest and safest dose of ACE-083 in adults with FSHD. Participants were divided into three dose groups (150mg, 200mg, 250mg), and received injections of ACE-083 into either the upper leg (tibialis anterior muscle), or the upper arm (biceps brachii muscle).
  • Part 2 is a randomised, double-blind, placebo-controlled study. This will start once Part 1 is complete. The best dose from Part 1 will be tested in Part 2.


Acceleron has released data from the 150mg and 200mg dose groups in Part 1. Overall the drug was well tolerated and no serious adverse events occurred.

Magnetic Resonance Imaging (MRI) was used to quantify the volume of the targeted upper leg or upper arm muscle. This was carried out before treatment (the baseline) and three weeks after the last injection of ACE-083.

The results showed that ACE-083 increased the volume of the upper leg by an average of 12.6%, and the upper arm by an average of 13.2%. The amount of fat in the leg and arm muscles also decreased.

While these results are promising, they are based on a small number of patients (23 in total) and there was no placebo to compare against. We also don’t yet know what effect ACE-083 has on muscle strength and function. This will be investigated in Part 2 of the study, which is due to start in the second quarter of 2018.

Dr Matthew Sherman, Chief Medical Officer of Acceleron, said:


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.



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