OMLONTI Ophthalmic solution Ref.[50996] Active ingredients: Omidenepag

Absorption

Omlonti is absorbed through the cornea where prodrug omidenepag isopropyl is hydrolyzed to become biologically active metabolite, omidenepag. After once daily ocular administration of one drop of omidenepag isopropyl 0.0025% eye drops to both eyes in humans for 7 days, plasma concentrations of omidenepag reached C_max at 10-15 minutes. Systemic exposure was similar between days 1 and 7, indicating no systemic accumulation.

Elimination

Metabolism

After topical ocular administration, omidenepag isopropyl is rapidly metabolized in the eye to omidenepag (active moiety) by carboxylesterase-1. The pharmacologically active form, omidenepag is further metabolized by liver through oxidation, N-dealkylation, glucuronidation, sulfate conjugation or taurine conjugation.

Excretion

In rats, 0.03% ¹⁴C-Omlonti was instilled in both eyes as a single dose (5 mcL/eye, 3 mcg/animal). By 168 hours after ocular instillation, 89% of the administered radioactive dose had been excreted. Specifically, 83% and 4% of the administered radioactive dose were excreted in the feces and urine, respectively, and radioactivity in expired air was below the lower limit of quantitation.

Carcinogenesis

Lifetime rodent studies have not been performed to evaluate the carcinogenic potential of omidenepag isopropyl or omidenepag.

In rats dosed by subcutaneous injection daily for 26 weeks, nephroblastoma and a spermatic cord tumor were found at 0.003 mg/kg/day (33 times the RHOD based on the estimated area under the curve [AUC]). Mammary adenocarcinoma and pituitary pars distalis adenomas were observed at 0.03 mg/kg/day (319 fold the RHOD based on the estimated AUC).

Mutagenesis

Omidenepag was not mutagenic in the bacterial reverse mutation (Ames) test and the in vivo mouse micronucleus test. Omidenepag isopropyl was positive (mutagenic and clastogenic) without metabolic activation in the in vitro mouse lymphoma forward mutation assay [see Clinical Pharmacology (12.3)].

Impairment of Fertility

In a rat fertility and early embryonic development study, daily subcutaneous doses of omidenepag isopropyl did not affect male or female fertility at doses up to 1 mg/kg/day (2,452 times the MRHOD based on estimated plasma C_max).

The rabbit embryofetal development study administered omidenepag isopropyl to pregnant rabbits beginning on gestation day 6, covering the period of implantation [see Use in Specific Populations (8.1)]. Preimplantation losses were observed at 0.8 mg/kg/day (3,696 times the MRHOD based on estimated plasma C_max). The NOAEL for rabbit preimplantation loss was 0.08 mg/kg/day (256 times the MRHOD based on estimated plasma C_max) [see Use in Specific Populations (8.1)].

Nasal cavity respiratory epithelium metaplasia was observed in cynomolgus monkeys receiving unilateral topical ocular instillations of omidenepag isopropyl at 0.003% (0.9 mcg/eye) [1.07 fold the MRHOD, based on ocular dose comparison]. In a 13-week monkey study, the 0.9 mcg/eye dose was associated with nasal cavity respiratory epithelial metaplasia, and increased nasal cavity goblet cell respiratory epithelium mucosa. In a 39-week monkey study, the 0.9 mcg/eye dose was associated with increased incidence and severity of nasal cavity respiratory epithelium metaplasia. These findings were present in both the treated side and untreated contralateral side, and they were also observed in the vehicle group [see Adverse Reactions (6)].

Omlonti was evaluated in three randomized and controlled clinical trials in subjects with open-angle glaucoma or ocular hypertension with average baseline IOP of 24-26 mm Hg. The double-masked treatment duration was 3 months in all 3 studies. The third study included a 9-month open-label treatment period following the 3-month double-masked treatment period.

In the three studies, IOP reductions were observed for all treatment arms. In the Omlonti arm, the reduction in IOP ranged from 5-7 mm Hg across all three studies. The corresponding reductions for the timolol and latanoprost arms were 5-7 mm Hg and 6-8 mm Hg, respectively.