Acceleron Pharmaceuticals has announced preliminary results from its ongoing phase 2 trial testing ACE-083 in adults with Charcot-Marie-Tooth disease (CMT). ACE-083 is a drug that inhibits a family of proteins that negatively regulate muscle growth (including myostatin).
This trial aims to build muscle mass and improve muscle strength in the tibialis anterior – a muscle in the lower leg. This muscle is responsible for lifting the front of the foot when you take a step. Weakness in this muscle can lead to foot drop and increase the risk of falls, which are a common problem for people with CMT.
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 CMT. 18 participants with CMT1 or CMTX were divided into three dose groups (150mg, 200mg or 240mg). They received an injection into both tibialis anterior muscles once every three weeks for three months.
- Part 2 is a randomised, double-blind, placebo-controlled study – this will test the best dose from Part 1 in 40 people with CMT over a six-month period.
Accerelon has released safety and efficacy data from Part 1 of the study. Overall the drug was generally well tolerated and no serious adverse events occurred.
Magnetic Resonance Imaging (MRI) was used to quantify the volume of the tibialis anterior muscle. This was carried out before treatment (the baseline) and three weeks after the last injection of ACE-083. Results showed that ACE-083 increased the volume of the tibialis anterior muscle by up to 14%. A small reduction in the amount of fat in the muscle was also noted.
Florian P. Thomas, M.D., principal investigator at Hackensack Meridian School of Medicine at Seton Hall University, said:
There are currently no FDA-approved therapies for patients with CMT with muscle weakness. The muscle volume and fat fraction changes demonstrated in Part 1 of the ACE-083 trial are encouraging. We’re hopeful that ACE-083 may become an important option for patients.
While these results are promising, we 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 third quarter of 2018. Preliminary results from Part 2 are expected by the end of 2019.
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