This study looks at how well a new treatment, ALN-AGT01 RVR, works for adults with mild to moderate hypertension (high blood pressure). It also checks how the body processes the drug and its safety. Participants will first take a medicine called zilebesiran, which helps lower blood pressure. The study has two parts, each testing a single dose (SD) of ALN-AGT01 RVR.

To join, participants must have a blood pressure of 130-170 mmHg or 140-170 mmHg, depending on the study part. They should either not be on any medicine or on stable medication, and they need to stop taking most other medicines before the study. People cannot participate if they have other causes for high blood pressure, high potassium levels, or poor kidney function.

• The study is only for adults with controlled blood pressure.
• Participants will receive a single dose of the new treatment.
• They must stop certain medications before joining.