What is the impact of plozasiran, an investigational siRNA targeting hepatic apoC-III, on lipoprotein particle concentration and subclass distribution in patients with severe hypertriglyceridemia and mixed hyperlipidemia?
NMR Lipoprotein Particle Test, studied in 403 patients (J Am Coll Cardiol 2025, PMID 40099777) — total LDL-P remained unchanged, but large LDL-P increased by +53% and medium LDL-P by +56%, while small LDL-P trended lower (-13%). Scope: 403 patients, and the abstract states no limitations.
Source: J Am Coll Cardiol 2025, PMID 40099777 ↗ · Research map · How Magellan grades evidence · evidence confidence: medium
J Am Coll Cardiol · 2025 · PMID 40099777 · DOI 10.1016/j.jacc.2025.03.496
Plozasiran significantly reduces harmful triglyceride-rich lipoproteins and shifts LDL to larger, potentially less atherogenic particles, without increasing overall LDL particle count.
The question
What is the impact of plozasiran, an investigational siRNA targeting hepatic apoC-III, on lipoprotein particle concentration and subclass distribution in patients with severe hypertriglyceridemia and mixed hyperlipidemia?
What they tested
Reductions in the number of triglyceride-rich lipoprotein particles (TRL-P) and a shift to possibly less atherogenic large low-density lipoprotein particles (LDL-P) are expected.
How they did it
This study analyzed data from 403 patients across two phase 2 studies, SHASTA-2 (severe hypertriglyceridemia) and MUIR (mixed hyperlipidemia). Patients received two subcutaneous doses of plozasiran (10, 25, or 50 mg) or placebo at baseline and week 12. Lipoprotein profiling was performed using nuclear magnetic resonance (NMR).
What they found
In SHASTA-2, plozasiran led to dose-dependent reductions in TRL-P, with total TRL-P decreasing by -46%. Total LDL-P remained unchanged, but large LDL-P increased by +53% and medium LDL-P by +56%, while small LDL-P trended lower (-13%). Total HDL-P increased by +8%, primarily due to a +36% increase in large HDL-P. In MUIR, total TRL-P was reduced by -48% (pooled plozasiran). Total LDL-P was unchanged, but large and medium LDL-P increased by +88% and +46% respectively, and small LDL-P decreased by -28%. Total HDL-P increased by +12%, driven by an +83% increase in large HDL-P.
| SHASTA-2 Total TRL-P Reduction | -46 | |
|---|---|---|
| SHASTA-2 Large LDL-P Increase | 53 | |
| SHASTA-2 Medium LDL-P Increase | 56 | |
| SHASTA-2 Small LDL-P Decrease | -13 | |
| SHASTA-2 Total HDL-P Increase | 8 | |
| SHASTA-2 Large HDL-P Increase | 36 | |
| MUIR Total TRL-P Reduction | -48 | |
| MUIR Large LDL-P Increase | 88 | |
| MUIR Medium LDL-P Increase | 46 | |
| MUIR Small LDL-P Decrease | -28 | |
| MUIR Total HDL-P Increase | 12 | |
| MUIR Large HDL-P Increase | 83 |
Percentage change in various lipoprotein particle concentrations and subclasses in SHASTA-2 and MUIR studies after plozasiran administration, relative to placebo or pooled plozasiran.
What it means
Plozasiran reduced apoC-III and induced potentially favorable quantitative and qualitative changes in lipoproteins, including a ~50% reduction in TRL-P, a shift in LDL to larger particles, and a modest increase in HDL-P concentration, without increasing total LDL-P or apoB.
Limitations
The abstract does not explicitly state limitations of the study. It suggests that the potential of plozasiran to lower cardiovascular risk needs to be evaluated in a prospective outcomes trial.
Where the published abstract does not list limitations, we say so rather than inventing them. Read the full paper on PubMed before drawing conclusions.
The paper at a glance
| Magellan’s evidence label | NMR LDL/HDL particle number (our label for this citation — see PubMed for the paper’s own title and authors) |
|---|---|
| Journal | J Am Coll Cardiol |
| Year | 2025 |
| PMID | 40099777 ↗ |
| DOI | 10.1016/j.jacc.2025.03.496 ↗ |
| Topic | Cardiovascular & vascular aging |
Read the source: PubMed record (authors, abstract, full citation) ↗ · Publisher via doi.org ↗
Where Magellan uses this paper
This citation sits behind the evidence grade on the pages below. Grades are set from the research and are independent of affiliate commissions.
NMR Lipoprotein Particle Test
Particle counts refine cardiovascular risk. Research relevant to this mechanism is indexed on PubMed and linked below; it describes the mechanism rather than this specific product.
Cite this page
These citations point at this summary. To cite the original paper with its full author list, use the PubMed record or doi.org.
Magellan Longevity. (2026). What is the impact of plozasiran, an investigational siRNA targeting hepatic apoC-III, on lipoprotein particle concentration and subclass distribution in patients with severe hypertriglyceridemia and mixed hyperlipidemia? [Plain-English summary of J Am Coll Cardiol 2025, PMID 40099777, DOI 10.1016/j.jacc.2025.03.496]. Magellan Longevity. https://magellanlongevity.com/study/s150.html@misc{magellan_s150,
title = {What is the impact of plozasiran, an investigational siRNA targeting hepatic apoC-III, on lipoprotein particle concentration and subclass distribution in patients with severe hypertriglyceridemia and mixed hyperlipidemia?},
author = {{Magellan Longevity}},
year = {2026},
howpublished = {\url{https://magellanlongevity.com/study/s150.html}},
note = {Plain-English summary of PubMed PMID 40099777; DOI 10.1016/j.jacc.2025.03.496; J Am Coll Cardiol 2025. Reviewed by Gabriel Radu, DO},
urldate = {2026-08-11}
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