ACE-031
Soluble ActRIIB-Fc decoy receptor for myostatin studied as a muscle-mass candidate; a protein biologic, not a peptide, with a discontinued clinical program.
Overview
ACE-031 is a soluble recombinant fusion protein consisting of the extracellular domain of activin receptor type IIB (ActRIIB) linked to an immunoglobulin Fc domain. Developed by Acceleron Pharma, it was designed as a decoy receptor that binds and neutralizes myostatin and related TGF-beta family ligands that restrain muscle growth.
It is a protein biologic rather than a small peptide. The clinical program appears to have been discontinued after early-phase studies.
Mechanism
Myostatin and activins normally signal through ActRIIB to limit skeletal muscle mass. By sequestering these ligands, ACE-031 was expected to relieve that brake and increase muscle growth, an effect demonstrated in animal models and reflected in lean-mass signals in early human studies.
Dosing
In early clinical studies, ACE-031 was administered by subcutaneous injection in single- and repeat-dose designs at various dose levels. No dosing is established for any indication today.
- Subcutaneous administration used in early clinical work
- Escalating single- and multiple-dose designs in phase 1-type studies
- Program discontinued; no approved dosing exists
Expected Effects
- Increases in lean body mass observed in animal models and suggested in early clinical data
- Effects on functional strength were not established
- Development was halted after early-phase results, with safety observations among the reasons reported
Side Effects & Tolerability
Reports from the early trials noted adverse events in some treated participants that contributed to discontinuation of the program. Long-term safety data are therefore unavailable.
Storage
As a research protein, store lyophilized material refrigerated or frozen as specified by the supplier, and handle reconstituted solutions according to the manufacturer's recommendations.