Pelacarsen (TQJ230/APO(a)-LRx) for Lp(a) Lowering: Phase 2 Randomized Trial

This Phase 2 randomized placebo-controlled trial evaluated pelacarsen (formerly APO(a)-LRx, TQJ230) — a GalNAc-conjugated antisense oligonucleotide targeting hepatic apo(a) mRNA — in 286 patients with established cardiovascular disease and elevated Lp(a) (≥60 mg/dL), using multiple dosing regimens.

Monthly dosing of pelacarsen 20 mg reduced Lp(a) by a median of 72%; monthly 40 mg produced 80% reduction; monthly 60 mg produced 81% reduction. Every-four-week dosing produced dose-dependent sustained reductions throughout the 6-month treatment period. OxPL/ApoB — the pro-inflammatory oxidized phospholipid cargo of Lp(a) — was reduced proportionally. Safety profile was acceptable with no dose-limiting toxicities.

This Phase 2 study established dose-response and safety parameters for pelacarsen, setting the stage for the Phase 3 HORIZON trial — a 7,680-patient randomized cardiovascular outcome trial powered to detect event reduction from ~80% Lp(a) lowering in high-Lp(a) patients with established cardiovascular disease. HORIZON began enrollment in 2020 with results expected approximately 2025.

The magnitude of Lp(a) reduction achievable with pelacarsen (72–81%) dwarfs what any existing therapy achieves — niacin reduces Lp(a) by ~20–30% with unacceptable tolerability; PCSK9 inhibitors reduce it 20–25% as a secondary effect. If HORIZON demonstrates cardiovascular event reduction proportional to the 80% Lp(a) lowering, it will establish a new class of lipid-lowering therapy for a prevalent high-risk condition that currently has no specific approved treatment.

We rate the evidence strong for a Phase 2 study. A dose-finding Phase 2 trial in 286 patients demonstrating that pelacarsen achieves 72–81% Lp(a) reduction with acceptable safety — the definitive preparatory study for the Phase 3 HORIZON outcome trial.