Background and objectives: Fimasartan (BR-A-657) is a novel, non-peptide angiotensin II receptor antagonist with a selective type I receptor blockade effect. Two first-in-human studies investigated the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of fimasartan.
Methods: Fasted single oral tablet doses of fimasartan 20-480 mg or placebo were administered to 40 healthy male subjects (aged 19-54 years) in a double-blind, randomized, sequential-group design. Subjects receiving fimasartan 240 mg also received the same treatment in the fed state after an interval of 7 days. In another study, oral tablet doses of fimasartan 120 and 360 mg or placebo were given once daily for 7 days to groups of eight fasted healthy male subjects (aged 20-55 years) in a double-blind, randomized, sequential-group design. Safety and tolerability were assessed. The PK and PD of fimasartan were also evaluated and compared for the different doses.
Results: Fimasartan was safe and well tolerated, but with an increased incidence of low BP and postural dizziness for the 360 mg dose after repeated administration. Fimasartan produced increases in plasma renin activity, angiotensin I and II, which were not dose dependent. Maximal increases occurred between 6 and 8 hours post-dose, lasting up to 48 hours. Fimasartan was absorbed rapidly after all doses and had a multiphasic distribution. Two peaks in the plasma concentration-time profile were observed in most subjects. Steady state was achieved after three doses, and accumulation was minimal after repeated doses for 7 days (24-30%). The effective half-life ranged from 9.84 to 13.2 hours. The systemic exposure of fimasartan was dose proportional, and no marked food effect was noted after administration of 240 mg in the fed state. Urinary excretion of fimasartan was very low (1.74-2.51%), suggesting non-renal elimination.
Conclusion: Fimasartan had a good safety profile and was well tolerated after fasted single oral doses of 20-480 mg, a fed single oral dose of 240 mg, and fasted repeated oral doses of 120 and 360 mg in healthy subjects. In addition, the PK and PD of fimasartan in this population were well characterized. Further studies are needed to evaluate the safety, efficacy, and dose-response relationship of fimasartan in patients with hypertension.