Efficacy and Tolerability of Fimasartan, a New Angiotensin Receptor Blocker, Compared With Losartan (50/100 mg): A 12-Week, Phase III, Multicenter, Prospective, Randomized, Double-Blind, Parallel-Group, Dose Escalation Clinical Trial With an Optional 12-Week Extension Phase in Adult Korean Patients With Mild-to-Moderate Hypertension