Inclisiran administration potently and durably lowers LDL-C over an extended-term follow-up: the ORION-8 trial.

BACKGROUND AND AIMS: Data describing the long-term efficacy, safety, and tolerability of inclisiran are limited. This was explored in ORION-8, an open-label extension study of preceding Phase 2 and Phase 3 placebo-controlled and open-label extension trials. METHODS: Adults with ASCVD, ASCVD risk equivalent, or HeFH received open-label inclisiran every 180 days (after completion of the parent trial) until Day 990, followed by an end-of-study (EOS) visit at Day 1080 or ≥90 days after last dose. Study endpoints included proportion of patients achieving pre-specified LDL-C goals (ASCVD: <1.8 mmol/L [<70 mg/dL]; ASCVD risk equivalent: <2.6 mmol/L [<100 mg/dL]), percentage and absolute changes in LDL-C at EOS, and safety of inclisiran. RESULTS: Of 3274 patients included in the analysis, 2446 (74.7%) were followed until EOS. Mean age was 64.9±9.9 years, 82.7% (n=2709) had ASCVD, and mean baseline LDL-C was 2.9±1.2 mmol/L. Mean cumulative exposure to inclisiran (including parent trials) was 3.7 years; maximum exposure was 6.8 years. With inclisiran, 78.4% (95% CI: 76.8, 80.0) of patients achieved pre-specified LDL-C goals and mean percentage LDL-C reduction was -49.4% (95% CI: -50.4, -48.3). No attenuation of LDL-C lowering over time was observed. Treatment-emergent adverse events at the injection site (all mild or moderate) occurred in 5.9% of inclisiran-treated patients. Inclisiran-associated anti-drug antibodies were infrequent (5.5%) and had no impact on the efficacy or safety of inclisiran. No new safety signals were identified. CONCLUSIONS: In the largest and longest follow-up to date, inclisiran demonstrated sustained and substantial LDL-C lowering with a favourable long-term safety and tolerability profile. ClinicalTrials.gov identifier: NCT03814187.

Long-term efficacy and safety of inclisiran in patients with high cardiovascular risk and elevated LDL cholesterol (ORION-3): results from the 4-year open-label extension of the ORION-1 trial.

INTRODUCTION: Whether long-term treatment with the twice-yearly, siRNA therapeutic inclisiran, which reduces hepatic production of proprotein convertase subtilisin/kexin type 9 (PCSK9), results in sustained reductions in LDL cholesterol with an acceptable safety profile is not known. The aim of this study was to assess the effect of long-term dosing of inclisiran in patients with high cardiovascular risk and elevated LDL cholesterol. METHODS: ORION-3 was a 4-year open-label extension study of the placebo-controlled, phase 2 ORION-1 trial, conducted at 52 sites across five countries. Patients with prevalent atherosclerotic cardiovascular disease or high-risk primary prevention and elevated LDL cholesterol despite maximally tolerated statins or other LDL-lowering treatments, or with documented statin intolerance, who had completed the ORION-1 trial were eligible. Patients receiving inclisiran in ORION-1 received twice-yearly 300 mg subcutaneous inclisiran sodium throughout ORION-3 (inclisiran-only arm), whereas patients receiving placebo in ORION-1 first received subcutaneous evolocumab 140 mg every 2 weeks until day 360 thereafter transitioning to inclisiran twice-yearly for the remainder of ORION-3 study (switching arm). The primary efficacy endpoint was the percentage change in LDL cholesterol with inclisiran from the start of ORION-1 through to day 210 of the open label extension phase in the inclisiran-only arm (approximately 570 days of total inclisiran exposure in the modified intention-to-treat population). Secondary and exploratory endpoints included changes in LDL-C cholesterol and PCSK9 concentrations levels up to day 1440 (4 years) in each arm, and safety. ORION-3 is registered with ClinicalTrials.gov, NCT03060577. FINDINGS: Of the original ORION-1 cohort of 497 patients, 290 of 370 patients allocated to drug continued into the inclisiran-only arm and 92 of 127 patients allocated to placebo entered the switching-arm in the ORION-3 extension study conducted between March 24, 2017, and Dec 17, 2021. In the inclisiran-only arm, LDL cholesterol was reduced by 47·5% (95% CI 50·7-44·3) at day 210 and sustained over 1440 days. The 4-year averaged mean reduction of LDL-C cholesterol was 44·2% (95% CI: 47·1-41·4), with reductions in PCSK9 ranging from 62·2% to 77·8%. Adverse events at the injection site were reported in 39 (14%) of 284 patients in the inclisiran-only arm and 12 (14%) of 87 patients in the switching arm. The incidence of treatment-emergent serious adverse events possibly related to the study drug was 1% (three of 284) in the inclisiran-only arm and 1% (one of 87) in the switching arm. INTERPRETATION: Twice-yearly inclisiran provided sustained reductions in LDL cholesterol and PCSK9 concentrations and was well tolerated over 4 years in the extension study. This is the first prospective long-term study to assess repeat hepatic exposure to inclisiran. FUNDING: Novartis Pharma.

LDL phenotype in subjects with mild cognitive impairment and Alzheimer's disease.

BACKGROUND: Centenarians with normal cognitive function have a "longevity phenotype" characterized by large low-density lipoproteins (LDL) and high-density lipoproteins (HDL) and low incidence of metabolic syndrome, hypertension, and cognitive impairment. Alzheimer's disease (AD) is associated with a number of cardiovascular risk factors, but it is not known if they have or lack the "longevity phenotype". OBJECTIVE: The study was designed to determine LDL size and body fat content and distribution in subjects with mild cognitive impairment (MCI) and AD. RESULTS: Fifty-eight persons with MCI or AD (cases) and 42 control subjects of similar age had measurement of LDL size and lipoprotein lipids after a 12 h fast and analysis of body composition by dual x-ray absorptiometry. Cases had small LDL size more often than controls (73% versus 66%) associated with significantly higher triglycerides, lower HDL cholesterol, and higher triglyceride/HDL cholesterol ratio (p ≤ 0.02). Cases with large LDL had a better lipoprotein profile than those with small LDL. Cases and controls had similar percent body fat, fat index, and lean mass index. Forty-seven percent of cases and 39% of controls were obese. CONCLUSION: The prevalence of small LDL phenotype in MCI and AD cases contrasts with the "longevity phenotype" reported for centenarians with preserved cognitive function. The small LDL phenotype is an atherogenic lipoprotein profile found in metabolic syndrome, type 2 diabetes, and insulin resistance. It is now also reported in persons with MCI and AD.

Plexins are GTPase-activating proteins for Rap and are activated by induced dimerization.

Plexins are cell surface receptors that bind to semaphorins and transduce signals that regulate neuronal development, immune responses, and other processes. Signaling through plexins has been proposed to rely on specific guanosine triphosphatase (GTPase)-activating protein (GAP) activity for R-Ras and M-Ras. Activation of this GAP activity of plexins appears to require simultaneous binding of semaphorin to the plexin extracellular domain and of the Rho GTPases Rac1 or Rnd1 to the cytoplasmic region. However, GAP activity of plexins has eluded detection in several recent studies. We show that the purified cytoplasmic region of plexin uses a noncanonical catalytic mechanism to act as a GAP for Rap, but not for R-Ras or M-Ras. The RapGAP activity of plexins was autoinhibited and was activated by induced dimerization. Biochemical and crystallographic analyses demonstrated that binding of Rho GTPases did not directly contribute to activation of plexin RapGAP activity. Semaphorin stimulated the RapGAP activity of full-length plexin in cells, which was required for plexin-mediated neuronal growth cone collapse. Together, these findings define a pathway for plexin signaling and provide insights into the mechanism for semaphorin-induced activation of plexins.