gp160

This is a double-blind, placebo-controlled and open-label, multicenter efficacy and long-term safety study of firibastat (QGC001) 1000 mg (2×500 mg tablets) administered po, QD, for up to 48 weeks in patients with difficult-to-treat/treatment-resistant HTN. Subjects will continue to take their chronic antihypertensive therapies (at least 2 classes of antihypertensive therapies) at the MTDs during the Run in Period and for the duration of the study. For treatment-resistant subjects, one of the antihypertensive therapies must be a diuretic; for difficult-to-treat subjects, the antihypertensive therapies do not have to include a diuretic. Subjects will complete subject medication diaries during the Run-in Period. If systolic automated office BP (AOBP) is ≥180 mmHg or diastolic BP (DBP) ≥110 mmHg at any visit during the study (and repeated and confirmed within 30 min), the subject will be withdrawn from the study and will receive appropriate treatment.