PCSK9 Inhibitors' New Users: Analysis of Prescription Patterns and Patients' Characteristics from an Italian Real-world Study

Background and Objective Cardiovascular (CV) diseases represent a major cause of death and severe medical condition worldwide. Different therapeutic options are available to control low-density lipoprotein cholesterol (LDL-C) level in order to prevent CV events. In recent years, two new drugs were approved for patients who are unable to reduce circulating LDL-C with the current therapies: evolocumab and alirocumab (proprotein convertase subtilisin/kexin type nine [PCSK9] inhibitors). This study was aimed to characterise patients who started treatment with PCSK9 inhibitors in the Tuscany region of Italy during the first year of public healthcare service reimbursement and to describe the pattern of PCSK9 inhibitor use in the first 6 months of treatment. Methods Patients on PCSK9 inhibitor treatment in Tuscany (3.7 million inhabitants) from 07/2017 to 06/2018 were selected from regional healthcare administrative databases. Concomitant use of lipid-lowering therapies (LLTs), adherence and persistence during the 6 months preceding the first PCSK9 inhibitor dispensing, as well as comorbidities since 1996, were described. In the first 6 months of PCSK9 inhibitor treatment, adherence, persistence and concomitant LLTs were assessed. Results There were 269 (176 evolocumab, 93 alirocumab) new users of PCSK9 inhibitors. Patients (mean age of 59.1 years) were mainly male (71.0%) in secondary prevention (70.2%) and affected by familial hypercholesterolaemia (53.5%). Sixty-six patients (24.5%) had diabetes mellitus and 12 (4.5%) chronic renal failure. In the 6 months prior to the first PCSK9 inhibitor administration, 61.3% of patients received at least one prescription of ezetimibe or high-intensity statins and 45.7% were persistent to these drugs. During follow-up, 79.9% of patients were adherent to PCSK9 inhibitor and 73.3% were persistent. Conclusions During the first year of availability, the rate of prescription of PCSK9 inhibitors appears below expectations. Patients were mainly in secondary prevention and had been slightly persistent to previous LLTs. During follow-up, the PCSK9 inhibitor monotherapy showed high levels of adherence and persistence. This real-world study sets the stage for future longer-term investigations useful to improve our knowledge on the appropriateness, drug access and public healthcare sustainability of PCSK9 inhibitors.