Participants will receive ALN-AGT01 or placebo for the first 6 months of the 12-month double-blind (DB) treatment period. Participants randomized to placebo will be re-randomized at Month 6 to 1 of the 4 initial ALN-AGT01 regimens until the end of the 12-month DB treatment period. Participants randomized to ALN-AGT01 regimens will remain on their originally assigned regimens through remainder of the study.
The purpose of this study is to evaluate the effect of ALN-AGT01 on systolic and diastolic blood pressure and to characterize the pharmacodynamic (PD) effects and safety of ALN-AGT01.