OBJECTIVES:  Patients with atherosclerotic cardiovascular disease (ASCVD) or heterozygous familial hypercholesterolemia (HeFH) on statin remain at high risk for cardiovascular (CV) events and may benefit from additional lipid-lowering therapy (LLT), such as PCSK9 inhibitors (PCSK9i). Yet patients and physicians are required to fulfill several steps before reimbursement, with up to 75% prescription denials. This analysis modeled the effects of delaying treatment with alirocumab (a PCSK9i) on CV event risk. METHODS:  A Markov cohort model with annual cycles was developed to estimate the long-term rate of CV events for patients with clinical ASCVD or HeFH on statins and high low-density lipoprotein cholesterol (LDL-C). CV events included acute coronary syndrome (ACS), revascularization, ischemic stroke, and CV death. The model estimated 3-year CV event risk when patients received add-on alirocumab at the start of the simulation or after 1- or 2-year delays. Baseline characteristics, annual CV risk and transition probabilities among ASCVD patients were estimated using real world data (with published literature for HeFH patients). CV risk reduction was based on Cholesterol Treatment Trialists’ (CTT) meta-analysis. Four high CV risk cohorts were modeled: 1) HeFH with ASCVD and LDL-C >130 mg/dL; 2) recent ACS (0-1 year) with LDL-C >70 mg/dL; 3) ASCVD with LDL-C >100 mg/dL; and 4) ASCVD with LDL-C >70 mg/dL. RESULTS:  For each aforementioned cohort, the model analyzed the 3-year CV risks when patients received add-on alirocumab at the simulation start or after 1- and 2-year delays: 1) 18.7%, 23.2%, and 27.5%; 2) 20.7%, 24.4%, and 26.2%; 3) 13.9%, 15.9%, and 17.7%; and 4) 13.5%, 15.0%, and 16.4%. Overall, 3-year CV event risk increased by an absolute +1.5% to +8.8%, or a relative increase of 11% to 47%. CONCLUSIONS:  Delaying treatment access to alirocumab was associated with a proportional increase in CV events of 11% to 47%.