First Oral PCSK9 Inhibitor Cuts LDL Cholesterol by 80% in Phase 1 Trial
Laroprovstat, a once-daily pill, slashed LDL by 80% when combined with rosuvastatin — rivaling injectable PCSK9 inhibitors.
Summary
For the first time, researchers have demonstrated that a PCSK9 inhibitor can be taken as a pill rather than an injection. Laroprovstat (AZD0780), developed by AstraZeneca, works through a novel mechanism — stabilizing a region of the PCSK9 protein to prevent it from destroying LDL receptors. In a Phase 1 trial, treatment-naive patients with hypercholesterolemia who took laroprovstat 30 mg alongside the statin rosuvastatin achieved an approximately 80% reduction in LDL cholesterol from baseline. The drug was well tolerated, showed predictable once-daily pharmacokinetics, and could be taken with or without food. These early results suggest laroprovstat could eventually offer patients a convenient oral alternative to injectable PCSK9 drugs like evolocumab and alirocumab.
Detailed Summary
High LDL cholesterol remains one of the most powerful modifiable risk factors for cardiovascular disease, the leading cause of death globally. While PCSK9 inhibitors have proven highly effective at lowering LDL, all approved agents require subcutaneous injections every two to four weeks — a barrier to adherence for many patients. Laroprovstat could change that equation entirely.
Researchers from AstraZeneca and Dogma Therapeutics conducted a randomized, single-blind, placebo-controlled Phase 1 trial of laroprovstat (AZD0780), a small-molecule PCSK9 inhibitor designed for oral administration. Unlike existing PCSK9 antibodies that block the PCSK9–LDL receptor interaction, laroprovstat binds to the PCSK9 C-terminal domain, stabilizing it and preventing lysosomal trafficking — ultimately preserving LDL receptors on the surface of liver cells where they clear LDL from the bloodstream.
In preclinical work, laroprovstat increased LDL receptor expression and lowered LDL cholesterol in mice engineered to express human PCSK9. In the human trial, single ascending doses confirmed dose-proportional pharmacokinetics and a half-life of approximately 40 hours, supporting once-daily dosing. Crucially, a high-fat meal caused no clinically meaningful change in drug exposure. After a three-week run-in on rosuvastatin 20 mg, participants receiving laroprovstat 30 mg achieved an additional 51% LDL reduction from baseline — totaling an approximately 80% reduction when combined with the statin.
These findings position laroprovstat as a potential oral complement or alternative to injectable PCSK9 therapies, potentially expanding access for patients with familial hypercholesterolemia or statin-intolerant individuals requiring aggressive LDL lowering.
Important caveats apply. This is a Phase 1 trial with a small sample size focused primarily on safety and pharmacokinetics, not long-term cardiovascular outcomes. Larger Phase 2 and Phase 3 trials will be needed to confirm efficacy, durability, and safety across broader patient populations.
Key Findings
- Laroprovstat 30 mg added to rosuvastatin 20 mg reduced LDL cholesterol by approximately 80% from baseline; the 1 mg dose plus rosuvastatin achieved approximately 70%.
- On top of a rosuvastatin 20 mg run-in, laroprovstat 30 mg produced an additional 51% LDL reduction (95% CI 44%–58%) and 1 mg produced 29% (95% CI 18%–38%) over 28 days.
- Novel mechanism: stabilizes PCSK9 C-terminal domain to prevent lysosomal trafficking and LDL receptor degradation, rather than blocking the PCSK9–LDL receptor interaction.
- Dose-proportional pharmacokinetics with ~40-hour half-life supporting once-daily oral dosing; no clinically meaningful food effect.
- Well tolerated with no safety findings of concern in this Phase 1 trial.
Methodology
This was a randomized, single-blind, placebo-controlled Phase 1 trial (NCT05384262) in treatment-naive adults with LDL-C between 100–190 mg/dL. Participants received laroprovstat 1 mg or 30 mg versus placebo once daily for 28 days following a rosuvastatin 20 mg run-in period; single ascending dose cohorts also assessed pharmacokinetics and safety in participants with LDL-C ≥70 mg/dL.
Study Limitations
This summary is based on the abstract only, as the full paper is not open access. The trial is a small Phase 1 study designed primarily to assess safety and pharmacokinetics, not cardiovascular outcomes. Long-term efficacy, safety in broader populations, and direct head-to-head comparisons with injectable PCSK9 inhibitors remain to be established in future trials.
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