7372 Anti-Corticotropin-Releasing Hormone (CRH) Monoclonal Antibody HBM9013 For The Treatment Of Congenital Adrenal Hyperplasia (CAH) And Polycystic Ovarian Syndrome (PCOS)

Abstract

Abstract Disclosure: H. Pan: None. L.L. Liu: None. Q. Lv: None. F.G. Grosveld: None. D. Drabek: None. R.V. Haperen: None. X. Wang: None. Y. He: None. Y. Wang: None. J. Huang: None. J. Lee: None. G. Zhang: None. J.J. Rong: None. H.V. Chen: None. J.A. Majzoub: Advisory Board Member; Self; Chair of SAB of Harbour BioMed Alpha Therapeutics, which owns the rights of HBM9013.. Stock Owner; Self; Equity Owner of Harbour BioMed Alpha Therapeutics, which owns the rights of HBM9013.. J.J. Zhao: None. Anti-Corticotropin-Releasing Hormone (CRH) Monoclonal Antibody HBM9013 for the Treatment of Congenital Adrenal Hyperplasia (CAH) and Polycystic Ovarian Syndrome (PCOS). Abstract Congenital Adrenal Hyperplasia (CAH) is a rare autosomal recessive genetic disease due to mutation of CYP21A2 which leads to deficiency of 21-Hydroxylase enzymatic activity. Classical CAH patients are born with life-threatening deficiency of glucocorticoid (GC) and mineralocorticoid. Due to this enzymatic block and the lack of negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis by GC, the adrenal gland produces excessive amounts of androgen which result in masculinized genitalia and virilization. The current standard care is supraphysiological doses of GC, which are difficult to balance between excess GC exposure and excess androgen secretion. Too little GC does not suppress production of androgen sufficiently and too much GC leads to Cushing Syndrome (CS). Previous work found that corticotropin-releasing hormone (CRH) is absolutely required for activation of the HPA axis during loss of GC negative feedback, via adrenocorticotropic hormone (ACTH) (1), which is necessary for production of adrenal androgens (2). We report here the development of Anti-CRH humanized monoclonal antibody HBM9013 (PR302334-24) for the treatment of CAH. HBM9013 binds to CRH with high affinity and neutralizes its signaling through both CRH Receptor 1 (CRHR1) and CRH Receptor 2 (CRHR2) in vitro. HBM9013 shows in vivo activities in two preclinical models. It blocks restraint stress-induced increases in plasma ACTH and corticosterone in mouse and rat. Mouse ACTH and Corticosterone were reduced from 210 ± 63 pg/ml to 27 ± 8 pg/ml (Mean ± SD, p = 5.2*10-6; IgG1 Control Group = 6 mice; HBM9013 Group = 8 mice) and from 303 ± 28 ng/ml to 57 ± 15 ng/ml (Mean ± SD, p = 6.2*10-[1][1]; IgG1 Control Group = 6 mice; HBM9013 Group = 8 mice), respectively. It also markedly reduces the constitutive, extremely elevated plasma ACTH levels in Mrap-knockout mice from 3847 ± 240 pg/mL to 1080 ± 302 pg/mL (Mean ± SD, n = 5 independent experiments, p = 2.3*10-7). HBM9013 has excellent CMC characteristics with ∼5 g/L titer and ∼80% yield. HBM9013 also has an excellent safety profile with no-observed-adverse-effect-level (NOAEL) of 150 mg/kg in weekly dosing for five doses in both rat and cynomolgus dose-ranging-finding (DRF) toxicology studies. HBM9013 is formulated up to 150 mg/ml as a weekly to monthly subcutaneous injection for ease of administration and compliance for CAH patient. HBM9013 could be a next generation therapy for CAH, in combination with a low physiological dose of GC that would avoid CS. Since ∼50% of Polycystic Ovarian Syndrome (PCOS) androgens may be of adrenal origin, we believe that HBM9013 could also be indicated for PCOS. References(1)Muglia LJ et al. J Clin Invest. 2000. 105:1269-77.(2)Weber A et al. Clin Endocrinol. 1997. 46:431-7. Presentation: 6/1/2024