Inclisiran is a small interfering RNA (siRNA) that lowers LDL cholesterol by silencing PCSK9 production inside the liver. After two starting doses it is given just twice a year — unusual among lipid-lowering therapies and well suited to patients who struggle with adherence. It lowers LDL-C by about 50% on top of a statin; cardiovascular outcome data are still awaited.
- Inclisiran is an siRNA that targets PCSK9 messenger RNA — it stops the liver making PCSK9, rather than mopping up the protein already in the circulation.
- Dosing is day 1, day 90, then every 6 months — a clear adherence advantage over daily tablets and the fortnightly or monthly PCSK9 antibodies.
- LDL-C falls by about 50%, with meaningful reductions in ApoB and non-HDL-C and a modest fall in lipoprotein(a).
- ORION-8 confirmed durable LDL-C lowering of ~49% out to 6.8 years, with no attenuation over time and no new safety signal.
- VICTORION-INITIATE (2024) showed an “inclisiran-first” strategy lowered LDL-C ~60% versus ~7% with usual care — without displacing statins.
- Cardiovascular outcome trials (ORION-4, VICTORION-2P) report from 2026 onward; until then, benefit rests on LDL-C as a surrogate.
- In Australia, inclisiran (Leqvio) is PBS-listed from April 2024 as an alternative to PCSK9 antibodies after maximally tolerated statins and ezetimibe.
What is inclisiran?
Inclisiran is a cholesterol-lowering drug that works on the same biological target as the PCSK9 antibodies, but from a different angle. Instead of binding PCSK9 protein in the bloodstream, it switches off the gene’s message before the protein is ever made. It belongs to a rapidly expanding class of RNA-interference therapeutics — drugs whose names end in –siran, for “siRNA” (small interfering RNA). Related agents include patisiran (which silences the TTR gene in amyloidosis) and zilebesiran (an investigational agent that silences angiotensinogen for hypertension).
The result is a large, durable fall in LDL cholesterol from an injection given only twice a year. For the upstream biology of PCSK9 and how lowering it raises LDL-receptor activity, see the companion article on PCSK9 inhibitors.
How it works: RNA interference
RNA interference is a natural gene-silencing system. Its first hint came from plant biologists in the 1980s who were trying to deepen the purple of petunias and instead produced white flowers — the colour gene had been unexpectedly silenced. The mechanism was defined by Andrew Fire and Craig Mello in the nematode C. elegans: injecting double-stranded RNA (dsRNA) matching a gene silenced that gene, and only a tiny amount was needed, implying the signal was being catalytically amplified. They received the 2006 Nobel Prize in Physiology or Medicine for the discovery.
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In the body, RNAi serves two natural roles: degrading viral RNA as an antiviral defence, and fine-tuning gene expression through microRNAs. Inclisiran borrows this same machinery — a synthetic siRNA designed to be complementary to PCSK9 mRNA directs the cell’s own silencing complex to destroy that message, so the liver stops producing PCSK9.
The RNAi pathway, step by step
1 · A double-stranded trigger enters the cell
The pathway is set off when a cell encounters double-stranded RNA — whether from a virus, a transposable element, or a therapeutic. The system responds to the double-stranded structure itself, which is why it can be aimed at almost any chosen messenger RNA.
2 · Natural RNAi uses Dicer, but inclisiran is already an siRNA
In the natural pathway, longer double-stranded RNA is processed by an enzyme called Dicer into short siRNA fragments. Inclisiran is different: it is already a short, chemically modified siRNA designed to match PCSK9 mRNA. After hepatocyte uptake, the inclisiran duplex is loaded straight into the silencing complex rather than needing to be generated from a long dsRNA precursor — and the chemical modifications built into its strands are what give the drug its months-long duration of action.
3 · RISC is loaded with the guide strand
The duplex is taken up by the RNA-induced silencing complex (RISC). The two strands separate: the “passenger” (sense) strand is discarded and the “guide” (antisense) strand stays bound to an Argonaute protein at the core of the complex.
4 · Target mRNA is destroyed
Guided by its antisense strand, RISC locates the matching PCSK9 mRNA, binds it, and the Argonaute protein cleaves it. The message is destroyed before it can be translated, so PCSK9 protein is never produced. One loaded RISC can cleave many copies of the target — the catalytic amplification Fire and Mello first observed.
In the original RNAi experiments, double-stranded RNA was far more potent than single strands. Inclisiran uses a duplex siRNA because loading into RISC depends on a guide/passenger-strand architecture — this improves potency, specificity and durability. (Single-stranded antisense oligonucleotides can also silence genes, but through a different mechanism.)
Liver-targeted delivery (GalNAc)
A drug that silences PCSK9 only helps if it reaches the liver, where PCSK9 is made. Inclisiran’s siRNA is conjugated to triantennary N-acetylgalactosamine (GalNAc), a high-affinity ligand for the asialoglycoprotein receptor expressed almost exclusively on hepatocytes. After subcutaneous injection the drug is rapidly taken up by the liver and internalised by endocytosis; free inclisiran is undetectable in plasma within about 48 hours. Inside the cell, the receptor recycles to the surface and the siRNA enters the silencing pathway above. This targeted delivery — not just the siRNA chemistry — is what makes a twice-yearly subcutaneous dose feasible.
One reassurance worth stating plainly: inclisiran is not a statin, not a vaccine, and not gene editing. Its effect is reversible — it lowers PCSK9 messenger-RNA production for months but does not permanently alter DNA.
Effect on LDL-C and other lipids
Inclisiran is given as inclisiran 284 mg (supplied as inclisiran sodium 300 mg) by subcutaneous injection on day 1 and day 90, then every six months. Across the ORION programme it lowers LDL-C by roughly 50% on top of a statin, with further reductions in the other atherogenic markers — most usefully ApoB and non-HDL-C, and a modest fall in lipoprotein(a). It is not a triglyceride-lowering therapy.
| Lipid fraction | Mean reduction from baseline |
|---|---|
| LDL-C | ~50% |
| ApoB | ~35–45% |
| Non-HDL-C | ~40–45% |
| Lipoprotein(a) | ~15–25% (median) |
| Triglycerides | Small and inconsistent (~10%); not a triglyceride therapy |
The time course is distinctive. After the day-1 and day-90 doses, LDL-C falls by roughly 45% at three months and around 54% at six months, then settles to a steady ~50% with each subsequent six-monthly injection — the level never drifts back to baseline between doses (Fig 3).
Inclisiran vs evolocumab
Both lower PCSK9, but they differ in mechanism, dosing, where they are given, and — importantly — in the maturity of their outcome evidence.
| Inclisiran (Leqvio) | Evolocumab (Repatha) | |
|---|---|---|
| Class | siRNA — blocks PCSK9 synthesis | Monoclonal antibody — binds circulating PCSK9 |
| Target | PCSK9 mRNA in hepatocytes | PCSK9 protein in plasma |
| LDL-C reduction | ~50% | ~50–60% |
| Dosing | Day 1, day 90, then 6-monthly | Every 2 weeks or monthly |
| Administered | By a healthcare professional | Self-injected at home |
| CV outcome data | Awaited (ORION-4, from 2026) | Proven (FOURIER; VESALIUS-CV 2025) |
| PBS (Australia) | Listed Apr 2024 | Listed, Authority criteria |
Inclisiran is most attractive when LDL-C remains above target despite maximally tolerated oral therapy and adherence is a major concern, or when a patient prefers a clinic-administered injection twice yearly rather than home self-injection every 2–4 weeks. A PCSK9 antibody may be preferred when the priority is established cardiovascular-outcomes evidence, or maximum LDL-C reduction with a self-administered therapy.
Why statins are continued
Statins and PCSK9-directed therapy are complementary, not interchangeable. Statins inhibit HMG-CoA reductase, which up-regulates LDL receptors and increases LDL clearance — but the same signal also raises PCSK9, which then degrades those receptors and caps the achievable LDL-C fall. Inclisiran removes that ceiling by suppressing PCSK9 production, preserving and amplifying the receptors a statin has up-regulated. Used together the two mechanisms produce a deeper LDL-C reduction than either alone (Fig 4), which is why a statin is normally continued unless genuinely not tolerated.
The adherence advantage
Chronic, symptomless conditions such as hypercholesterolaemia are undermined by poor persistence. About 30% of patients stop a PCSK9 antibody by six months and roughly half by three years; daily tablets fare worse still. Because LDL-related risk depends on cumulative lifetime exposure, every gap in therapy erodes benefit.
Inclisiran’s six-monthly, clinic-administered schedule reframes the problem: when the patient attends, the dose is observed and documented, removing the daily-tablet or home-injection burden entirely (Fig 5). This is its single most distinctive clinical feature, and the rationale behind the “inclisiran-first” strategy now being tested.
Trial evidence: ORION & VictORION
The phase 3 ORION trials established that inclisiran lowers LDL-C durably and safely. More recent data extend the follow-up and test how the drug performs in real-world practice. The clinical question that remains — whether this LDL-C lowering translates into fewer cardiovascular events — is the subject of large outcome trials now reporting from 2026.
| Trial | Population | Key result |
|---|---|---|
| ORION-9 (2020) | 482 with heterozygous FH | ~48% LDL-C reduction at day 510 |
| ORION-10 (2020) | 1561 with established ASCVD | ~52% LDL-C reduction at day 510 |
| ORION-11 (2020) | 1617 with ASCVD or risk-equivalent | ~50% LDL-C reduction at day 510 |
| ORION-8 (2024) | 3274 in open-label extension; up to 6.8 yr | ~49% LDL-C reduction sustained; 78% at goal; no attenuation |
| VICTORION-INITIATE (2024) | 450 with ASCVD, “inclisiran-first” vs usual care | LDL-C −60% vs −7%; 4–8× more reached goal |
ORION-8: durability out to nearly 7 years
ORION-8 followed 3,274 patients from the earlier ORION-3, -9, -10 and -11 studies — over 12,000 patient-years of exposure, with the longest individual exposure 6.8 years. LDL-C remained reduced by a mean of 49.4%, with 78.4% of patients reaching their pre-specified goal and no attenuation of effect over time. Among very-high-risk patients with ASCVD, two-thirds reached an LDL-C below 1.4 mmol/L. It is the largest and longest experience to date with any siRNA therapy.
VICTORION-INITIATE: an “inclisiran-first” strategy
This pragmatic, real-world US trial randomised patients with ASCVD not at goal on a maximally tolerated statin to either usual care or immediate addition of inclisiran. The “inclisiran-first” group achieved a 60% LDL-C reduction at day 330 versus just 7% with usual care, and were four to eight times more likely to reach guideline targets — with non-inferior statin discontinuation, confirming inclisiran adds to, rather than replaces, statin therapy.
Large cardiovascular outcome trials are still in progress. ORION-4 (16,124 patients with established ASCVD) has completed enrolment but has no results posted; primary completion is expected in late 2026. VICTORION-2P (~15,000 with established CVD) is ongoing, with VICTORION-1P (high-risk primary prevention) to follow — part of the broader VictORION programme of more than 30 trials and over 60,000 patients. Until these report, inclisiran should be described as having proven, durable LDL-C lowering but not yet a proven reduction in myocardial infarction, stroke or cardiovascular death. The hard-outcome benefit shown for the PCSK9 antibodies cannot simply be assumed to transfer.
Safety
Across the programme inclisiran has shown a favourable, consistent safety profile. The most common drug-related issue is an injection-site reaction, such as pain, redness or rash. In the pivotal trials these occurred in 8.2% of inclisiran-treated patients versus 1.8% with placebo; they were usually mild or moderate, transient, and rarely led to discontinuation (0.2%). Broader pooled analyses have not shown a meaningful excess of liver, kidney, muscle or new-onset diabetes events compared with placebo. Anti-drug antibodies are infrequent (~5% during treatment) and do not affect efficacy or safety. A pooled analysis of seven ORION trials — the largest safety dataset for any siRNA — found no new signals over a mean exposure approaching three years. As with any newer therapy, long-term post-marketing surveillance continues.
Monitoring, missed doses & practical issues
A few practical points follow from the dosing schedule and the drug’s profile:
Monitoring. Check the LDL-C response after initiation and periodically thereafter; the fall is established by about three to six months and is stable between doses. Our cholesterol unit converter helps if results are reported in mg/dL rather than mmol/L.
Keep other therapy going. Continue the statin and ezetimibe unless they are not tolerated — inclisiran is additive, not a replacement.
Switching from a PCSK9 antibody. Inclisiran can be started immediately after the last dose of evolocumab; to maintain LDL-C lowering it is best given within about two weeks of that last antibody dose.
| If a dose is missed… | What to do |
|---|---|
| Less than 3 months late | Give the dose now and keep the original schedule. |
| More than 3 months late | Restart: dose now, again at 3 months, then every 6 months. |
Special populations. No dose adjustment is needed for older patients or for mild–moderate renal or hepatic impairment. Data are limited in severe hepatic impairment (use with caution) and experience is limited in end-stage renal disease. Inclisiran should be avoided in pregnancy and breastfeeding.
Inclisiran in Australia: PBS access and who may benefit
Inclisiran is for high-risk patients who remain above their LDL-C target despite optimised conventional therapy — those with established ASCVD or familial hypercholesterolaemia on a maximally tolerated statin, or who cannot tolerate statins. Ezetimibe and bempedoic acid are generally tried first or alongside; where LDL-C is still off target, a PCSK9-directed therapy is indicated. A structured stepwise approach helps in severe hyperlipidaemia. The choice between inclisiran and an antibody often comes down to adherence and patient preference: a clinic-based twice-yearly injection versus home self-injection with proven outcome data.
Inclisiran (Leqvio) has been PBS-listed since 1 April 2024 as a subsidised alternative to the PCSK9 antibodies, for adults with heterozygous familial hypercholesterolaemia, or non-familial hypercholesterolaemia with ASCVD and additional risk factors, who remain above target on a maximally tolerated statin (if tolerated) plus ezetimibe. It is Authority Required for initiation (online or telephone) and Authority Required (Streamlined) for continuation. The restriction criteria are specific and revised periodically — confirm current eligibility against the PBS schedule at the time of prescribing.
In practice, initiation usually follows specialist assessment of the LDL-C target, ASCVD or familial hypercholesterolaemia status, statin tolerance, ezetimibe use and adherence factors.
Frequently asked questions
Is Leqvio the same as inclisiran?
Yes. Leqvio is the brand name; inclisiran is the active drug. They refer to the same medicine, made by Novartis.
Is inclisiran a PCSK9 inhibitor?
Broadly, yes — it lowers PCSK9, the same target as evolocumab. But it works differently: rather than blocking the PCSK9 protein, it stops the liver from producing it, by silencing the PCSK9 gene’s messenger RNA.
How is inclisiran different from other PCSK9 inhibitors?
Inclisiran is a small interfering RNA that stops the liver from making PCSK9 in the first place. Evolocumab is a monoclonal antibody that binds and neutralises PCSK9 already in the bloodstream. Inclisiran is injected twice a year after two starting doses; evolocumab is injected every two to four weeks.
How often is inclisiran given?
An injection on day 1, again at about three months, then once every six months. It is given under the skin by a healthcare professional.
How much does inclisiran lower cholesterol?
About 50% on top of a statin, with further reductions in ApoB and non-HDL cholesterol and a modest fall in lipoprotein(a). The effect is steady between doses and durable over years.
Does inclisiran lower lipoprotein(a)?
It produces a modest reduction in lipoprotein(a) — roughly 15–25% on average — but it is not a dedicated Lp(a)-lowering therapy. Agents designed specifically to lower Lp(a) are still in trials.
Does inclisiran replace statins?
No. Statins remain first-line. Inclisiran is added when a high-risk patient is still above target on a maximally tolerated statin and other therapy, or when statins genuinely cannot be tolerated. The two have complementary mechanisms and work better together.
Can I switch from Repatha to inclisiran?
Yes. Inclisiran can be started straight after the last dose of evolocumab (Repatha); to keep LDL-C low it is best given within about two weeks of that final antibody dose. Your cardiologist will plan the changeover.
What happens if I miss an inclisiran dose?
If the dose is less than three months overdue, it is given and the original six-monthly schedule continues. If it is more than three months overdue, treatment is restarted — a dose now, another at three months, then six-monthly.
Has inclisiran been shown to reduce heart attacks and strokes?
Not yet directly. Inclisiran is approved on its substantial LDL-C lowering, which is a well-validated marker of risk. The large cardiovascular outcome trials — ORION-4 and VICTORION-2P — report from 2026 and will confirm whether that lowering translates into fewer events.
Is inclisiran available on the PBS in Australia?
Yes. It has been listed on the PBS since April 2024 for eligible patients with familial hypercholesterolaemia, or hypercholesterolaemia with atherosclerotic cardiovascular disease, who remain above target despite maximally tolerated statins and ezetimibe. The Authority criteria are specific and can change, so eligibility is checked against the current PBS schedule.
Is inclisiran safe?
The main side effect is an injection-site reaction — around one in twelve patients in the pivotal trials, usually mild. Pooled trial data, including the largest safety dataset for any siRNA, show no meaningful increase in liver, kidney, muscle or diabetes problems compared with placebo. Long-term monitoring continues, as with any newer medicine.
References & further reading
Clinical references
- Ray KK, Wright RS, Kallend D, et al. Two phase 3 trials of inclisiran in patients with elevated LDL cholesterol (ORION-10 and ORION-11). N Engl J Med. 2020.
- Raal FJ, Kallend D, Ray KK, et al. Inclisiran for the treatment of heterozygous familial hypercholesterolaemia (ORION-9). N Engl J Med. 2020.
- Wright RS, Raal FJ, Koenig W, et al. Inclisiran potently and durably lowers LDL-C over extended follow-up (ORION-8). Cardiovasc Res. 2024.
- Koren MJ, Rodriguez F, East C, et al. An “inclisiran first” strategy vs usual care in patients with atherosclerosis (VICTORION-INITIATE). J Am Coll Cardiol. 2024.
- Wright RS, Raal FJ, Koenig W, et al. Pooled safety analysis of inclisiran across seven ORION trials. J Am Coll Cardiol. 2025.
- Ray KK, Raal FJ, Kallend DG, et al. Inclisiran and cardiovascular events: a patient-level analysis of phase III trials. Eur Heart J. 2022.
- Ray KK, Stoekenbroek RM, Kallend D, et al. Effect of 1 or 2 doses of inclisiran on LDL-C: one-year follow-up of ORION-1. JAMA Cardiol. 2019.
- ORION-4 / HPS-4 / TIMI-65. Effects of inclisiran on clinical outcomes in ASCVD (registration NCT03705234). University of Oxford; ongoing.
Further reading on this site
Cholesterol not reaching target?
Dr Reza Moazzeni provides specialist assessment of high cardiovascular risk, familial hypercholesterolaemia and non-statin therapy — including PCSK9-directed treatment — at Westmead and St Leonards. A current referral is required for consultation.
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