Melanocyte-stimulating hormones, neuropeptides induced by Pro-opiomelanocortin (POMC) in the hypothalamus, act as the endogenous ligands of Melanocortin 4 receptor (MC4R). They decrease appetite by MC4R activation, leading to weight loss. Dysfunction of genes in MC4R pathway is known to cause rare genetic obesity such as POMC deficiency, leptin receptor deficiency, Bardet-Biedl syndrome and Alström syndrome. Therefore, MC4R agonists have the potential to be therapeutic agents for such genetic obesities. Compound LB(LB) is an orally available, small molecule MC4R agonist under clinical development. In vitro activity of LB toward MC4R and selectivity over MC1R, MC3R and MC5R were measured by radio-ligand binding, luciferase, cAMP and β-arrestin assays. LB showed a high potency and selectivity toward MC4R. In vivo efficacy of LB was tested in high fat diet-induced obese mice, rats and KK-Ay mice. Following repeat-dose to obese rodents, LB led to appetite suppression and weight loss comparable to or higher than setmelanotide. To evaluate in vivo pharmacokinetic properties, a single dose of LB was administered to mice, rats, dogs and monkeys. The GLP toxicology program of LB was comprised of general toxicity studies in rats and monkeys up to 4 weeks, genotoxicity and safety pharmacology studies. The IND-enabling toxicology studies demonstrated good safety profiles in the rats and monkeys. LB showed no significant safety issue in the genotoxicity and safety pharmacology studies. Comprehensive in vitro and in vivo studies demonstrated that LB is potent and selective MC4R agonist. LB is safe and well-tolerated compound, as demonstrated in GLP toxicity studies. In addition, the observed efficacy and safety profiles of LB are well described by the preclinical pharmacokinetic properties of LB such as a great penetration to brain tissue.
In conclusion, these nonclinical studies suggested that LB can be a safe and effective drug for the patients with genetic obesity.
H. Park: None. S. Yeo: None. H. Park: Employee; Self; LG Chem. J. Park: None. P.S. Hong: None.