Therapeutic PCSK9 targeting: Inside versus outside the hepatocyte?

Area of Science:

• Cardiovascular Pharmacology
• Lipid Metabolism
• Drug Development

Background:

• Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of LDL receptor (LDLR) activity and plasma LDL-cholesterol (LDL-C) levels.
• Targeting PCSK9 offers a significant therapeutic strategy for lipid-lowering and cardiovascular risk reduction.

Purpose of the Study:

• To critically appraise pharmacological strategies targeting PCSK9, both intracellularly and extracellularly.
• To compare the efficacy, pharmacokinetics, and pharmacodynamics of different PCSK9 inhibitor classes.

Main Methods:

• Review of scientific literature on PCSK9 inhibitors, including monoclonal antibodies (mAbs) and small interfering RNA (siRNA).
• Analysis of waterfall plots demonstrating individual patient responses to PCSK9 inhibition.
• Comparison of LDL-C reduction percentages and effects on plasma PCSK9 levels between drug classes.

Main Results:

• Both mAbs (alirocumab, evolocumab) and siRNA (inclisiran) effectively reduce LDL-C and improve cardiovascular outcomes.
• mAbs achieve slightly higher LDL-C reduction (≈60%) compared to siRNA (≈50%), though head-to-head trials are needed.
• Both classes provide additional LDL-C lowering beyond statins, aiding achievement of treatment goals in high-risk patients.

Conclusions:

• PCSK9 inhibitors represent a vital therapeutic option for managing hypercholesterolemia and reducing cardiovascular risk.
• Distinct pharmacokinetic and pharmacodynamic profiles of mAbs and siRNA may offer different clinical applications.
• Ongoing development of novel PCSK9 inhibitors and gene editing strategies promises further advancements in lipid management.