Silence Therapeutics plc announced positive topline 36-week data from the ongoing ALPACAR-360 phase 2 study of zerlasiran (SLN360) in 178 subjects with baseline lipoprotein(a), or Lp(a), levels at or over 125 nmol/L at high risk of atherosclerotic cardiovascular disease (ASCVD) events. Zerlasiran is a siRNA (short interfering RNA) designed to lower the body?s production of Lp(a), a key genetic risk factor for cardiovascular disease affecting up to 20% of the world?s population. In the double-blind placebo-controlled treatment period, zerlasiran was administered at 300 mg subcutaneously every 16 or 24 weeks and 450 mg every 24 weeks to patients with a median baseline Lp(a) of approximately 215 nmol/L. These data demonstrated a highly significant reduction from baseline in Lp(a) compared to placebo to 36 weeks (primary endpoint).

Median percentage reduction in Lp(a) of 90% or greater were observed for both doses at week 36. No new safety concerns were identified during this treatment period. The 60-week study is ongoing and secondary endpoints, including change in Lp(a) from baseline to 48 weeks (end of treatment period), 60 weeks (end of study) and potential effects on other lipids/lipoproteins, will be evaluated.

Silence plans to report topline 48-week data from the ALPACAR-360 study in the second quarter of this year.