Ezetimibe and Inclisiran Together: What the Trials Show

What each drug does

Ezetimibe (Zetia) is a cholesterol absorption inhibitor, not a statin. It blocks the sterol transporter Niemann-Pick C1-Like 1 (NPC1L1) at the brush border of the small intestine; less cholesterol reaches the liver, hepatic cholesterol stores fall and LDL receptors increase, clearing LDL-C from the blood [2]. In a 2-week trial in 18 patients, ezetimibe inhibited cholesterol absorption by 54% compared with placebo [2].

Inclisiran (Leqvio) is a small interfering RNA, not a monoclonal antibody and not a statin. The GalNAc conjugate is taken up by liver cells, where it directs breakdown of PCSK9 messenger RNA; with less PCSK9, more LDL receptors are recycled to the hepatocyte surface and more LDL-C is pulled out of circulation [3].

How much does ezetimibe lower LDL-C?

In two 12-week placebo-controlled trials in 1,719 adults with primary hyperlipidemia, ezetimibe 10 mg lowered LDL-C by 18% against a 1% rise on placebo, with maximal response within about 2 weeks [2].

The add-on numbers matter more here. In an 8-week trial of 769 patients already on a statin and above their LDL goal, adding ezetimibe lowered LDL-C by a further 25%, against 4% when placebo was added [2]. Started at the same time as atorvastatin 10 mg, the combination produced a 53% reduction versus 37% with atorvastatin alone [2].

How much does inclisiran lower LDL-C?

ORION-10 (1,561 patients with atherosclerotic cardiovascular disease) and ORION-11 (1,617 patients with ASCVD or a risk equivalent) gave inclisiran 284 mg on day 1, day 90 and then every 6 months, on top of a maximally tolerated statin. Mean baseline LDL-C was about 105 mg/dL. At day 510 the placebo-corrected LDL-C reduction was 52.3% in ORION-10 and 49.9% in ORION-11 [1].

In 482 adults with heterozygous familial hypercholesterolemia and a mean baseline LDL-C of 153 mg/dL, LDL-C fell 39.7% on inclisiran and rose 8.2% on placebo at day 510, a between-group difference of 47.9 percentage points [5].

Has ezetimibe plus inclisiran been tested together?

The ezetimibe trials above gave it alone or added it to an ongoing statin, and ORION-10 and ORION-11 added inclisiran to a maximally tolerated statin [2][1]. These results describe each drug separately; they do not report the effect of the two drugs together, and the two sets of trials are not a head-to-head comparison.

Is there an interaction between ezetimibe and inclisiran?

The Zetia label lists three clinically important interactions: cyclosporine, where both ezetimibe and cyclosporine concentrations rise and cyclosporine levels are monitored; fibrates other than fenofibrate, which are not recommended, with fenofibrate and ezetimibe both raising cholesterol excretion into bile and cholecystectomy rates of 0.6% on fenofibrate alone versus 1.7% with ezetimibe; and bile acid sequestrants such as cholestyramine, which lower ezetimibe exposure, so ezetimibe is taken at least 2 hours before or 4 hours after [2]. Ezetimibe is conjugated by glucuronidation with minimal CYP oxidation [2].

Inclisiran is not a substrate, inhibitor or inducer of cytochrome P450 enzymes or transporters, and no formal clinical drug interaction studies were done; in a population pharmacokinetic analysis it did not clinically significantly change atorvastatin or rosuvastatin concentrations [3]. The Leqvio prescribing information lists no specific interacting drug [3].

Ezetimibe with a statin: what the Zetia label says

The Zetia label defers to the prescribing information of the statin, fenofibrate or other LDL-C lowering therapy for those products' risks and warnings [2]. In its statin combination trials, consecutive transaminase elevations of 3 times the upper limit of normal or more occurred in 1.3% of patients taking ezetimibe with a statin versus 0.4% on a statin alone [2].

What the labels say to watch for

Zetia has no boxed warning. Its warnings cover liver enzymes and skeletal muscle effects: myopathy and rhabdomyolysis are possible, and in postmarketing reports most patients who developed rhabdomyolysis were also taking a statin or another agent such as a fibrate; the label says to discontinue ezetimibe and other concomitant medications as appropriate if myopathy is suspected [2]. In monotherapy trials, upper respiratory tract infection occurred in 4.3% versus 2.5% on placebo and diarrhea in 4.1% versus 3.7% [2].

Leqvio has no boxed warning. Its only warning is hypersensitivity: anaphylaxis and angioedema have been reported after approval, and the label says patients should seek prompt medical attention for symptoms [3]. A prior serious hypersensitivity reaction is a contraindication [3]. In pooled adult placebo-controlled trials (1,833 on inclisiran versus 1,822 on placebo), injection-site reactions occurred in 8% versus 2%, arthralgia in 5% versus 4% and bronchitis in 4% versus 3% [3].

Dosing and practical differences

Ezetimibe is a 10 mg tablet once daily, with or without food, and LDL-C can be assessed as early as 4 weeks after starting [2]. The label does not recommend it in moderate or severe hepatic impairment, where exposure to total ezetimibe is about 3- to 4-fold higher [2].

Leqvio is given by a healthcare professional as 284 mg initially, again at 3 months, then every 6 months. It is not a self-injected product [3].

Do either of these drugs prevent heart attacks and strokes?

IMPROVE-IT randomized 18,144 patients hospitalized for acute coronary syndrome within the previous 10 days to simvastatin 40 mg plus ezetimibe 10 mg or simvastatin 40 mg plus placebo, with a median follow-up of 6 years. The median time-weighted LDL-C was 53.7 mg/dL with ezetimibe versus 69.5 mg/dL without. The primary composite of cardiovascular death, nonfatal myocardial infarction, unstable angina requiring rehospitalization, coronary revascularization or nonfatal stroke occurred in 32.7% with ezetimibe versus 34.7% without at 7 years, a hazard ratio of 0.936 (95% CI 0.89 to 0.99; p=0.016) [4]. The trial tested ezetimibe with simvastatin, and the Zetia label carries no cardiovascular risk-reduction indication [2].

There is no such result for inclisiran: ORION-10 and ORION-11 measured LDL-C and were not designed to show reduced cardiovascular events [1].