Silence Therapeutics shared positive topline 36-week data from its ongoing phase 2 study of zerlasiran, a long-acting agent directed at lowering Lp(a) levels.
In a statement, the company said the study shows a highly significant reduction from baseline in Lp(a) levels with zerlasiran compared with placebo at 36 weeks, the primary endpoint.
Zerlasiran (formerly known as SLN360), is a short interfering RNA (siRNA) agent, or “ gene silencing” therapy. It binds to and temporarily blocks the action of the LPA gene which encodes for apolipoprotein(a), a dominant and a rate-limiting component in the hepatic synthesis of the Lp(a) particle.
A previous phase 1 study showed that single subcutaneous doses of the drug, ranging from 30 mg to 600 mg, produced a dose-dependent reduction in Lp(a) plasma levels at 45-60 days.
The current double-blind placebo-controlled phase 2 trial — known as ALPACAR-360 — enrolled 178 patients at high risk for atherosclerotic cardiovascular events who had elevated levels of Lp(a), ie, ≥ 125 nmol/L (median baseline Lp(a) was approximately 215 nmol/L). They were randomized to zerlasiran or placebo.
Zerlasiran was administered at 300 mg subcutaneously every 16 or 24 weeks or at 450 mg every 24 weeks.
The 60-week study is ongoing, and secondary endpoints, including change in Lp(a) from baseline to 48 weeks (end of treatment period) and 60 weeks (end of study) and potential effects on other lipids/lipoproteins, will be evaluated.
Silence says it plans to report topline 48-week data from the ALPACAR-360 study in the second quarter of this year.
Elevated levels of Lp(a) represent a genetic risk factor for cardiovascular disease, which is believed to affect approximately 20% of the population. Although there are currently no approved Lp(a)-lowering therapies, several drug candidates are in late-stage clinical testing.
A version of this article appeared on Medscape.com.