HJB647 Phase 1b Study in Japanese Healthy Participants With Elevated Blood Pressure and Patients With Hypertension

Randomized, placebo-controlled, participant- and investigator-blind study consisting of two parts: * Part 1 (SAD part): Single oral dose in healthy participants. Sentinel dosing will be applied in each cohort. * Part 2 (MAD part): Multiple oral doses in patients with hypertension. Safety reviews will guide dose escalation and up-titration.