Characteristics and Outcomes of Patients Treated With Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors (The Mayo Clinic Experience)

Sex differences in efficacy and safety of PCSK9 monoclonal antibodies: A real-world registry

BACKGROUND AND AIMS

Proprotein convertase subtilisin/kexin 9 monoclonal antibodies (PCSK9 mAbs) reduce low-density lipoprotein (LDL-c) with a favourable safety profile. Available data from PCSK9 antibody trials suggest LDL-c reduction is lower in women compared to men. Data in real-world setting is scarce. The aim of this study was to assess sex differences in efficacy and safety of PCSK9 antibodies in clinical care.

METHODS

All patients starting with evolocumab or alirocumab in our lipid clinic were included in a prospective registry. We collected clinical information, including baseline and follow-up mean LDL-C levels after initiation of PCSK9 mAbs treatment. In addition, side effects and PCSK9 mAbs discontinuation were recorded.

RESULTS

We analysed 436 patients (209 women), mean age 58 ± 11 years. Women had higher baseline LDL-c levels compared to men (4.7 ± 1.6 mmol/L vs 4.1 ± 1.4 mmol/L, p < 0.01). PCSK9 mAbs resulted in less relative LDL-c reduction in women compared to men (50% vs 61% p<0.01), but equal absolute LDL-c reduction (respectively 2.3 ± 1.3 mmol/L vs 2.5 ± 1.1 mmol/L, p = 0.087). Women less often reached LDL-c target levels than men (50% vs 72%). No sex differences were observed in reporting of side effects (women 32% vs men 27% p = 0.26) or PCSK9 mAbs discontinuation (women 13% vs men 10%, p = 0.46).

CONCLUSIONS

In clinical practice, PCSK9 mAbs are less effective in reducing LDL-c levels in women compared to men and equally safe, implying the importance of sex differences in PCSK9 metabolism.

Trends in PCSK9 Inhibitor Prescriptions before and after the Price Reduction in Patients with Atherosclerotic Cardiovascular Disease

BACKGROUND

Proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors reduce low-density lipoprotein (LDL) cholesterol and cardiovascular event rates, yet due to their high price remain underutilized and difficult to prescribe in clinical practice. In March 2018, their price was significantly reduced. We evaluated whether the price reduction would improve prescribing patterns of PCSK9 inhibitors in eligible patients with atherosclerotic cardiovascular disease (ASCVD).

METHODS

We identified the number of eligible ASCVD patients and those prescribed a PCSK9 inhibitor for each year between July 2015 and December 2019. Patient demographics and clinical characteristics for those prescribed a PCSK9 inhibitor were extracted from their electronic health record.

RESULTS

In total 1059 patients of eligible patients received a new prescription for a PCSK9 inhibitor. From 2015 to 2019, the rate of new prescriptions among eligible patients increased from 0.5 to 3.3% (p < 0.001) and continuation rates increased from 18 to 60% (p < 0.001). Following the price reduction, patients who were prescribed a PCSK9 inhibitor were younger and more likely to be female, but less likely to have Medicare insurance.

CONCLUSIONS

Despite the reduction in the cost of PCSK9 inhibitors, most eligible patients are not prescribed one. The reduction in cost has improved adherence, primarily in patients with commercial insurance. Older patients and those on Medicare still face significant barriers in accessing a PCSK9 inhibitor. Further reductions in the price of the PCSK9 inhibitors are needed as is further study of the barriers that exist in prescribing one.

PCSK9 inhibition in clinical practice: Treatment patterns and attainment of lipid goals in a large health maintenance organization

BACKGROUND

Proprotein convertase subtilisin/kexin type-9 inhibitors (PCSK9i) effectively reduce low-density lipoprotein cholesterol (LDL-C), improving cardiovascular outcomes in clinical trials when added to statin therapy.

OBJECTIVES

As real-world evidence is lacking, we aimed to evaluate treatment and adherence patterns using PCSK9i in clinical practice.

METHODS

We investigated 1600 patients initiating PCSK9i between January 2016 and December 2019 in a large health maintenance organization. Treatment discontinuation was defined as a gap ≥60 days between last days' supply of one prescription and the start of the next. Re-initiation rates as well as proportion of days covered (PDC) over 1-year period and attainment of lipid goals under PCSK9i, were analyzed.

RESULTS

Evolocumab 140 mg was initiated by 50.7%, alirocumab 75 mg by 29.5% and 150 mg by 19.8%. Cumulative discontinuation rates were 28.1% after 6-months and 49.9% after 3-years. Overall, 58% of the patients that discontinued therapy have re-initiated PCSK9i (31% after 3-months from discontinuation). Mean PDC over 1-year of therapy was 56% ± 29, with PDC ≥80% evident in 29%. Of those with established cardiovascular disease (n = 991), 55% achieved LDL-C<70 mg/dL and 38% LDL-C<55 mg/dL. Attainment rates were lower in patients with PDC<80%, baseline LDL-C>190 mg/dL and in those not treated with concurrent statin therapy.

CONCLUSIONS

In real-world practice of patients treated by PCSK9i, high proportion of early treatment discontinuation was evident, with non-negligible re-initiation rates but overall low medication coverage over time. This have contributed to sub-optimal attainment of LDL-C treatment goals, particularly observed in patients with severe hypercholesterolemia, inadequate drug adherence, and those using PCSK9i as monotherapy.

Statin-Related Myotoxicity: A Comprehensive Review of Pharmacokinetic, Pharmacogenomic and Muscle Components

Statins are a cornerstone in the pharmacological prevention of cardiovascular disease. Although generally well tolerated, a small subset of patients experience statin-related myotoxicity (SRM). SRM is heterogeneous in presentation; phenotypes include the relatively more common myalgias, infrequent myopathies, and rare rhabdomyolysis. Very rarely, statins induce an anti-HMGCR positive immune-mediated necrotizing myopathy. Diagnosing SRM in clinical practice can be challenging, particularly for mild SRM that is frequently due to alternative aetiologies and the nocebo effect. Nevertheless, SRM can directly harm patients and lead to statin discontinuation/non-adherence, which increases the risk of cardiovascular events. Several factors increase systemic statin exposure and predispose to SRM, including advanced age, concomitant medications, and the nonsynonymous variant, rs4149056, in SLCO1B1, which encodes the hepatic sinusoidal transporter, OATP1B1. Increased exposure of skeletal muscle to statins increases the risk of mitochondrial dysfunction, calcium signalling disruption, reduced prenylation, atrogin-1 mediated atrophy and pro-apoptotic signalling. Rare variants in several metabolic myopathy genes including CACNA1S, CPT2, LPIN1, PYGM and RYR1 increase myopathy/rhabdomyolysis risk following statin exposure. The immune system is implicated in both conventional statin intolerance/myotoxicity via LILRB5 rs12975366, and a strong association exists between HLA-DRB1*11:01 and anti-HMGCR positive myopathy. Epigenetic factors (miR-499-5p, miR-145) have also been implicated in statin myotoxicity. SRM remains a challenge to the safe and effective use of statins, although consensus strategies to manage SRM have been proposed. Further research is required, including stringent phenotyping of mild SRM through N-of-1 trials coupled to systems pharmacology omics- approaches to identify novel risk factors and provide mechanistic insight.