Alnylam Pharmaceuticals’ RNA interference therapy zilebesiran failed to significantly reduce blood pressure in a key Phase 2 trial involving high-risk patients already on standard hypertension treatments. The 300 mg dose resulted in a non-significant 5 mmHg reduction at three months compared to placebo; higher doses showed no added benefit. Despite this, Alnylam plans to initiate a Phase 3 cardiovascular outcomes trial, signaling confidence in further development. Results were presented at the European Society of Cardiology meeting in 2025.