Discovery of BE2012, a First-in-Class REV-ERBα/β Antagonist with Favorable Selectivity and Pharmacokinetics, and In Vivo Efficacy in Inducing Key Myogenic Factors for Muscle Repair upon Acute Muscle Injury

REV-ERBα is a nuclear receptor transcriptional repressor implicated in circadian regulation, metabolism, inflammation, and myogenesis. Antagonism of REV-ERBα has recently emerged as a promising therapeutic strategy, yet few antagonists with suitable pharmacokinetic profiles have been identified since the discovery of SR8278 in 2011. Herein, we report the discovery and optimization of BE2012, a 3-aminoquinazolinone scaffold identified through high-throughput screening and refined via systematic structure–activity relationship (SAR) studies. Key pharmacophore elements were defined, including the essential role of the amino group and the tolerance of strategic R3 substitutions, which enabled the generation of nanomolar-potency analogues. Molecular modeling revealed critical hydrophobic and hydrogen-bonding interactions that stabilize BE2012 within the REV-ERBα ligand-binding domain. BE2012 demonstrated potent antagonist activity (EC₅₀ = 0.285 μM), high selectivity against a nuclear receptor panel, minimal off-target CNS interactions, and favorable in vitro ADME characteristics. Biological activity of BE2012 was confirmed in a murine model of acute muscle injury, in which a 5-day treatment induced key myogenic transcription factors, as did SR8278. Compared to SR8278, BE2012 exhibited markedly superior pharmacokinetic properties, with a ~22-fold longer half-life (t₁/₂ = 3.79 h vs. 0.17 h) and extended hepatic and skeletal muscle exposure. Further optimization yielded BE17201, a pharmacokinetically optimized analogue with higher systemic exposure than BE2012 (AUC = 11,782 vs 4,023 h·ng/mL) while maintaining functional efficacy. Collectively, these findings establish BE2012 as a first-in-class, selective, and pharmacokinetically favorable REV-ERBα/ antagonist, providing a robust platform for development of therapeutics to enhance skeletal muscle development and treat a range of diseases.