Preclinical Development and Phase 1 Trial of a Novel siRNA Targeting Lipoprotein(a)

This study reported preclinical development and the first human trial of olpasiran — a small interfering RNA designed to silence the LPA gene and dramatically reduce circulating lipoprotein(a).

In 64 healthy volunteers and patients with elevated Lp(a), subcutaneous olpasiran produced dose-dependent, sustained Lp(a) reductions exceeding 97 percent at the highest doses — lasting months after a single injection. No serious adverse events were observed. Preclinical animal work was concordant with the human findings, supporting dose translation.

The clinical significance is hard to overstate in the context of the Lp(a) field. Until this generation of RNA therapeutics, no safe agent could substantially reduce Lp(a) — a genetically determined, lifelong cardiovascular risk factor for which statins and other lipid drugs have minimal effect. Olpasiran’s phase 1 results established proof of mechanism: RNA interference can target LPA specifically and safely. Phase 2 (OCEAN[a]-DOSE) and phase 3 outcome trials are now underway.

We rate the evidence moderate. A successful phase 1 establishes safety and pharmacology but not clinical benefit; the cardiovascular endpoint trials will determine whether this dramatic Lp(a) reduction translates to fewer heart attacks and strokes.