Dual PCSK9 Inhibition With Inclisiran and Alirocumab in Secondary Prevention

Atherosclerotic cardiovascular disease remains a leading cause of morbidity and mortality, with elevated low-density lipoprotein cholesterol (LDL-C) being a major modifiable risk factor. Despite the availability of effective lipid-lowering therapies, a substantial proportion of high-risk patients fail to achieve recommended LDL-C targets, particularly those with statin intolerance.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a key role in regulating LDL receptor degradation and plasma LDL-C levels. Pharmacological inhibition of PCSK9 has emerged as an effective strategy to reduce LDL-C. Two distinct therapeutic approaches are currently available: monoclonal antibodies (such as alirocumab), which neutralize circulating PCSK9, and small interfering RNA therapies (such as inclisiran), which reduce hepatic production of PCSK9.

Although both approaches have demonstrated efficacy, real-world data suggest that monotherapy may not be sufficient for many high-risk patients. The combination of these two mechanisms may provide additive or synergistic effects, leading to more profound LDL-C reduction.

This study is designed as a prospective, randomized, open-label, monocentric clinical trial. Approximately 60 adult patients in secondary prevention with statin intolerance and elevated LDL-C (2.5-5.0 mmol/L) will be enrolled. Participants will be randomized in a 1:1:1 ratio to receive inclisiran, alirocumab, or a combination of both therapies.

Inclisiran will be administered subcutaneously at baseline and at 3 months. Alirocumab will be administered subcutaneously at a dose of 300 mg every 4 weeks in a supervised clinical setting. Patients will be followed for 9 months, with study visits at baseline, 1 month, 3 months, 6 months, and 9 months.

The primary endpoint is the percentage change in LDL-C from baseline at 3 and 9 months. Secondary endpoints include the proportion of patients achieving guideline-recommended LDL-C targets, changes in other lipid parameters, and safety outcomes including adverse events and treatment tolerability.

This study aims to provide proof-of-concept evidence on the effectiveness and safety of dual PCSK9 inhibition using complementary mechanisms, with potential implications for improving lipid management in high-risk, statin-intolerant patients.

Inclusion criteria

• Adults aged ≥18 years
• Established atherosclerotic cardiovascular disease (secondary prevention), defined as prior cardiovascular events or imaging-confirmed atherosclerosis (e.g., coronary artery disease on angiography or CT, carotid plaque on ultrasound, or peripheral arterial disease).
• Eligible for PCSK9 inhibitor therapy according to national clinical criteria
• Fasting LDL cholesterol ≥2.5 mmol/L and ≤5.0 mmol/L at screening
• Documented statin intolerance or contraindication to statin therapy
• On stable background lipid-lowering therapy (including ezetimibe if applicable) for at least 4 weeks prior to enrollment
• Able and willing to provide written informed consent

Exclusion criteria

• Eligibility for PCSK9 inhibitor therapy solely based on elevated lipoprotein(a) >1000 mg/L with LDL-C below inclusion threshold
• Prior use of any PCSK9 inhibitor (alirocumab, evolocumab or inclisiran) before enrollment
• Planned initiation or modification of lipid-lowering therapy during the study period
• Known homozygous familial hypercholesterolemia
• Active liver disease or alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >3× upper limit of normal
• Severe renal impairment (eGFR <30 mL/min/1.73 m²)
• Active malignancy or life expectancy <1 year
• Pregnancy, breastfeeding, or women of childbearing potential not using effective contraception
• Known hypersensitivity to inclisiran, alirocumab, or any of their excipients
• Participation in another interventional clinical trial within 30 days prior to enrollment
• Any condition that, in the opinion of the investigator, would interfere with study participation or interpretation of results