Zilebesiran (Alnylam Pharmaceuticals), an investigational, subcutaneously administered small-interfering RNA (siRNA) therapeutic in development for the treatment of hypertension, met the primary and secondary endpoints, with an “encouraging” safety profile in the phase 2 KARDIA-1 study, the company announced.
KARDIA-1 is a phase 2 randomized, double-blind, placebo-controlled, dose-ranging study evaluating the efficacy and safety of zilebesiran as monotherapy in 394 adults with mild to moderate untreated hypertension or on stable therapy with one or more antihypertensive drugs.
Patients were randomly assigned to one of five treatment arms during a 12-month double-blind period and double-blind extension period: 150 mg or 300 mg zilebesiran subcutaneously once every 6 months, 300 mg or 600 mg zilebesiran subcutaneously once every 3 months, or placebo. Patients taking placebo were randomly assigned to one of the four initial zilebesiran dose regimens beginning at month 6.
The primary endpoint was change from baseline in systolic blood pressure (SBP) at 3 months assessed by 24-hour ambulatory blood pressure monitoring.
Topline data show a dose-dependent, clinically significant reduction in 24-hour mean SBP, with a placebo-subtracted reduction greater than 15 mm Hg (P < .0001) with both the 300 mg and 600 mg doses.
The study also met key secondary endpoints, showing “consistent and sustained reductions” in SBP at 6 months, which supports quarterly or biannual dosing, the company said.
There was one death due to cardiopulmonary arrest in a zilebesiran-treated patient that was considered unrelated to the drug. Serious adverse events were reported in 3.6% of zilebesiran-treated patients and 6.7% of placebo-treated patients. None was considered related to the study drug.
Adverse events occurring in 5% or more of zilebesiran-treated patients in any dose arm included COVID-19, injection-site reaction, hyperkalemia, hypertension, upper respiratory tract infection, arthralgia, and headache.
“As a physician, I believe these KARDIA-1 results, which demonstrate clinically significant reductions in systolic blood pressure of greater than 15 mm Hg, along with the ability to achieve durable tonic blood pressure control, provide hope that we may one day have access to a novel therapy with the potential to address the significant unmet needs of patients with uncontrolled hypertension who are at high risk of future cardiovascular events,” study investigator George L. Bakris, MD, director, American Heart Association Comprehensive Hypertension Center, University of Chicago Medicine, said in a statement.
The phase 2 results “further validate” the phase 1 results, published in the New England Journal of Medicine, Simon Fox, PhD, vice president, zilebesiran program lead at Alnylam, said in the statement.
The full KARDIA-1 results will be reported at an upcoming scientific conference, the statement notes. Topline results from the KARDIA-2 phase 2 study of zilebesiran in combination with one of three standard classes of antihypertensive medications in patients with mild to moderate hypertension are expected in early 2024.
A version of this article first appeared on Medscape.com.