Recombinant human lecithin-cholesterol acyltransferase in patients with atherosclerosis: phase 2a primary results and phase 2b design.

AIMS: Reverse cholesterol transport (RCT) removes cholesterol and stabilizes vulnerable plaques. In addition, high-density lipoprotein (HDL) may be cardioprotective in acute myocardial infarction (MI). Lecithin-cholesterol acyltransferase (LCAT) may enhance RCT. The objective of this study was to investigate the pharmacokinetics, pharmacodynamics, and safety of multiple ascending doses of recombinant human LCAT (MEDI6012) to inform a Phase 2b programme. METHODS AND RESULTS: This was a randomized, blinded, placebo-controlled, dose-escalation Phase 2a study of MEDI6012. Patients were randomized into one of four cohorts (40, 120, 300 mg IV weekly ×3 doses, or 300 mg IV-push, 150 mg at 48 h and 100 mg at 7 days). All cohorts were planned to randomize 6:2 (MEDI6012 vs. placebo). The primary endpoints were baseline-adjusted area under the curve (AUC) from 0 to 96 h post dose 3 (AUC 0-96 h) for HDL-C, HDL cholesteryl ester (HDL-CE), and total cholesteryl ester (CE). The primary safety endpoints were treatment-emergent adverse events. A total of 32 patients were randomized. MEDI6012 significantly increased AUC 0-96 h for HDL-C, HDL-CE and CE in a graded fashion with increasing doses. Relative to placebo, MEDI6012 increased HDL-C at Day 19 by 66% (95% CI 33-99, P = 0.014) with 120 mg and 144% (95% CI 108-181, P < 0.001) with 300 mg. An IV-push increased HDL-C by 40.8% at 30 min. Overall adverse events were similar between groups with no severe, life-threatening/fatal adverse events, or neutralizing antibodies. CONCLUSIONS: Multiple ascending doses of MEDI6012 were safe and well tolerated and significantly increased HDL-C, HDL-CE and CE in a dose-related manner. These data support the ongoing Phase 2b programme investigating MEDI6012 in ST-elevation MI.

MEDI6012: Recombinant Human Lecithin Cholesterol Acyltransferase, High-Density Lipoprotein, and Low-Density Lipoprotein Receptor-Mediated Reverse Cholesterol Transport.

Background MEDI6012 is recombinant human lecithin cholesterol acyltransferase, the rate-limiting enzyme in reverse cholesterol transport. Infusions of lecithin cholesterol acyltransferase have the potential to enhance reverse cholesterol transport and benefit patients with coronary heart disease. The purpose of this study was to test the safety, pharmacokinetic, and pharmacodynamic profile of MEDI6012. Methods and Results This phase 2a double-blind study randomized 48 subjects with stable coronary heart disease on a statin to a single dose of MEDI6012 or placebo (6:2) (NCT02601560) with ascending doses administered intravenously (24, 80, 240, and 800 mg) and subcutaneously (80 and 600 mg). MEDI6012 demonstrated rates of treatment-emergent adverse events that were similar to those of placebo. Dose-dependent increases in high-density lipoprotein cholesterol were observed with area under the concentration-time curves from 0 to 96 hours of 728, 1640, 3035, and 5318 should be: mg·h/mL in the intravenous dose groups and 422 and 2845 mg·h/mL in the subcutaneous dose groups. Peak mean high-density lipoprotein cholesterol percent change was 31.4%, 71.4%, 125%, and 177.8% in the intravenous dose groups and 18.3% and 111.2% in the subcutaneous dose groups, and was accompanied by increases in endogenous apoA1 (apolipoprotein A1) and non-ATP-binding cassette transporter A1 cholesterol efflux capacity. Decreases in apoB (apolipoprotein B) were observed across all dose levels and decreases in atherogenic small low-density lipoprotein particles by 41%, 88%, and 79% at the 80-, 240-, and 800-mg IV doses, respectively. Conclusions MEDI6012 demonstrated an acceptable safety profile and increased high-density lipoprotein cholesterol, endogenous apoA1, and non-ATP-binding cassette transporter A1 cholesterol efflux capacity while reducing the number of atherogenic low-density lipoprotein particles. These findings are supportive of enhanced reverse cholesterol transport and a functional high-density lipoprotein phenotype. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02601560.

Familial lecithin:cholesterol acyltransferase deficiency: First-in-human treatment with enzyme replacement.

BACKGROUND: Humans with familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) have extremely low or undetectable high-density lipoprotein cholesterol (HDL-C) levels and by early adulthood develop many manifestations of the disorder, including corneal opacities, anemia, and renal disease. OBJECTIVE: To determine if infusions of recombinant human LCAT (rhLCAT) could reverse the anemia, halt progression of renal disease, and normalize HDL in FLD. METHODS: rhLCAT (ACP-501) was infused intravenously over 1 hour on 3 occasions in a dose optimization phase (0.3, 3.0, and 9.0 mg/kg), then 3.0 or 9.0 mg/kg every 1 to 2 weeks for 7 months in a maintenance phase. Plasma lipoproteins, lipids, LCAT levels, and several measures of renal function and other clinical labs were monitored. RESULTS: LCAT concentration peaked at the end of each infusion and decreased to near baseline over 7 days. Renal function generally stabilized or improved and the anemia improved. After infusion, HDL-C rapidly increased, peaking near normal in 8 to 12 hours; analysis of HDL particles by various methods all revealed rapid sequential disappearance of preß-HDL and small α-4 HDL and appearance of normal α-HDL. Low-density lipoprotein cholesterol increased more slowly than HDL-C. Of note, triglyceride routinely decreased after meals after infusion, in contrast to the usual postprandial increase in the absence of rhLCAT infusion. CONCLUSIONS: rhLCAT infusions were well tolerated in this first-in-human study in FLD; the anemia improved, as did most parameters related to renal function in spite of advanced disease. Plasma lipids transiently normalized, and there was rapid sequential conversion of small preß-HDL particles to mature spherical α-HDL particles.

Safety and Tolerability of ACP-501, a Recombinant Human Lecithin:Cholesterol Acyltransferase, in a Phase 1 Single-Dose Escalation Study.

RATIONALE: Low high-density lipoprotein-cholesterol (HDL-C) in patients with coronary heart disease (CHD) may be caused by rate-limiting amounts of lecithin:cholesterol acyltransferase (LCAT). Raising LCAT may be beneficial for CHD, as well as for familial LCAT deficiency, a rare disorder of low HDL-C. OBJECTIVE: To determine safety and tolerability of recombinant human LCAT infusion in subjects with stable CHD and low HDL-C and its effect on plasma lipoproteins. METHODS AND RESULTS: A phase 1b, open-label, single-dose escalation study was conducted to evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics of recombinant human LCAT (ACP-501). Four cohorts with stable CHD and low HDL-C were dosed (0.9, 3.0, 9.0, and 13.5 mg/kg, single 1-hour infusions) and followed up for 28 days. ACP-501 was well tolerated, and there were no serious adverse events. Plasma LCAT concentrations were dose-proportional, increased rapidly, and declined with an apparent terminal half-life of 42 hours. The 0.9-mg/kg dose did not significantly change HDL-C; however, 6 hours after doses of 3.0, 9.0, and 13.5 mg/kg, HDL-C was elevated by 6%, 36%, and 42%, respectively, and remained above baseline ≤4 days. Plasma cholesteryl esters followed a similar time course as HDL-C. ACP-501 infusion rapidly decreased small- and intermediate-sized HDL, whereas large HDL increased. Pre-ß-HDL also rapidly decreased and was undetectable ≤12 hours post ACP-501 infusion. CONCLUSIONS: ACP-501 has an acceptable safety profile after a single intravenous infusion. Lipid and lipoprotein changes indicate that recombinant human LCAT favorably alters HDL metabolism and support recombinant human LCAT use in future clinical trials in CHD and familial LCAT deficiency patients. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01554800.

HDL-targeted therapies: progress, failures and future.

Since the discovery in the 1970s that plasma levels of high-density lipoprotein cholesterol (HDL-C) are inversely associated with cardiovascular outcome, it has been postulated that HDL is anti-atherogenic and that increasing HDL-C levels is a promising therapeutic strategy. However, the recent failure of three orally active, HDL-C-raising agents has introduced considerable controversy, prompting the question of whether increasing the cholesterol cargo of HDL in a non-selective manner is an effective pharmacological approach for the translation of its atheroprotective and vasculoprotective activities. The interrelationships between HDL-C concentration, HDL particle number and levels of diverse HDL particle subpopulations of defined composition are complex, as are their relationships with reverse cholesterol transport and other anti-atherogenic functions. Such complexity highlights the incompleteness of our understanding of the biology of HDL particles. This article examines the HDL hypothesis in molecular and mechanistic terms, focusing on features that have been addressed, those that remain to be tested, and potential new targets for future pharmacological interventions.