Exploring rates of PCSK9 inhibitor persistence and reasons for treatment non-persistence in an integrated specialty pharmacy model.

Background: Nearly 40% of patients do not continue proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9i) therapy after 6 months, despite their ability to lower low-density lipoprotein cholesterol (LDL-C) and risk of cardiovascular events. Limited work has assessed persistence to PCSK9i therapy in an integrated specialty pharmacy model.

Objective: To assess rates of persistence to PCSK9i therapy and report reasons for non-persistence in patients serviced within an integrated specialty pharmacy.

Methods: We conducted a single-center, retrospective review of patients prescribed a PCSK9i at an academic health system between September 2015 and August 2018. Persistence was calculated as a binary measure (yes/no) of whether the patient was still receiving PCSK9i therapy at 3-, 12-, and 24-months; frequency distributions described reasons for non-persistence and descriptive statistics described the change in LDL-C from baseline to 24 months.

Results: 477 patients met inclusion criteria, 53% were male with median age of 63 years [IQR 56-70]. Median LDL-C at baseline was 157mg/dL and 86% had an atherosclerotic cardiovascular disease indication. Persistence at 3-, 12-, and 24-months was 94%, 80%, and 68%, respectively. Of the 262 patients persistent on PCSK9i therapy at 24 months with LDL-C values available, median LDL-C was 65 mg/dL. The most common reasons for non-persistence at 24 months included medication adverse effects (54%) and loss to follow-up (17%).

Conclusions: High rates of persistence to PCSK9i were seen in patients receiving care within an integrated specialty pharmacy model compared with rates in previous studies, suggesting specialty pharmacists may play a role in mitigating many common reasons for PCSK9i non-persistence.