Antisense inhibition of apoB synthesis with mipomersen reduces plasma apoC-III and apoC-III-containing lipoproteins.

Mipomersen, an antisense oligonucleotide that reduces hepatic production of apoB, has been shown in phase 2 studies to decrease plasma apoB, LDL cholesterol (LDL-C), and triglycerides. ApoC-III inhibits VLDL and LDL clearance, and it stimulates inflammatory responses in vascular cells. Concentrations of VLDL or LDL with apoC-III independently predict cardiovascular disease. We performed an exploratory posthoc analysis on a subset of hypercholesterolemic subjects obtained from a randomized controlled dose-ranging phase 2 study of mipomersen receiving 100, 200, or 300 mg/wk, or placebo for 13 wk (n = 8 each). ApoC-III-containing lipoproteins were isolated by immuno-affinity chromatography and ultracentrifugation. Mipomersen 200 and 300 mg/wk reduced total apoC-III from baseline by 6 mg/dl (38-42%) compared with placebo group (P < 0.01), and it reduced apoC-III in both apoB lipoproteins and HDL. Mipomersen 100, 200, and 300 mg doses reduced apoB concentration of LDL with apoC-III (27%, 38%, and 46%; P < 0.05). Mipomersen reduced apoC-III concentration in HDL. The drug had no effect on apoE concentration in total plasma and in apoB lipoproteins. In summary, antisense inhibition of apoB synthesis reduced plasma concentrations of apoC-III and apoC-III-containing lipoproteins. Lower concentrations of apoC-III and LDL with apoC-III are associated with reduced risk of coronary heart disease (CHD) in epidemiologic studies independent of traditional risk factors.

Efficacy of apolipoprotein B synthesis inhibition in subjects with mild-to-moderate hyperlipidaemia.

AIMS: Mipomersen, an apolipoprotein (apo) B synthesis inhibitor, has been shown to produce potent reductions in apoB and LDL-cholesterol levels in animal models as well as healthy human volunteers. A randomized, double-blind, placebo-controlled, dose-escalation study was designed to evaluate the efficacy and safety of mipomersen monotherapy with or without dose loading in subjects with mild-to-moderate hyperlipidaemia. METHODS AND RESULTS: Fifty subjects with LDL-cholesterol levels between 119 and 266 mg/dL were enrolled into five cohorts at a 4:1 randomization ratio of active to placebo. Two 13-week dose regimens were evaluated at doses ranging from 50 to 400 mg/week. Mipomersen produced dose-dependent reductions in all apoB containing lipoproteins. In the 200 and 300 mg/week dose cohorts, mean reductions from baseline in LDL cholesterol were -45 ± 10% (P= 0.000) and -61 ± 8% (P= 0.000), corresponding to a -46 ± 11% (P= 0.000) and -61 ± 7% (P= 0.000) decrease in apoB levels. Triglyceride levels were also lowered with median reductions up to 53% (P= 0.021). The most common adverse events were injection site reactions. Seven of 40 subjects (18%) showed consecutive transaminase elevations >3× upper limit of normal. Five of these subjects received 400 mg/week, four of whom had apoB levels below the limit of detection. As a consequence, the 400 mg/week cohort was discontinued. CONCLUSIONS: Mipomersen administered as monotherapy in subjects with mild-to-moderate hyperlipidaemia produced potent reductions in all apoB-containing lipoproteins. Higher doses were associated with hepatic transaminase increases.

Lack of pharmacokinetic interaction of mipomersen sodium (ISIS 301012), a 2'-O-methoxyethyl modified antisense oligonucleotide targeting apolipoprotein B-100 messenger RNA, with simvastatin and ezetimibe.

BACKGROUND AND OBJECTIVES: Mipomersen sodium (ISIS 301012) is a 20-mer phosphorothioate antisense oligonucleotide that is complementary to human apolipoprotein B-100 (apoB-100) messenger RNA and subsequently reduces translation of ApoB-100 protein, the major apolipoprotein of very low-density lipoprotein, intermediate-density lipoprotein and low-density lipoprotein (LDL). Mipomersen sodium is currently being studied in phase II/III clinical studies to determine its clinical utility as add-on therapy to HMG-CoA reductase inhibitors or other lipid-lowering agents in subjects with hypercholesterolaemia. The aim of this study was to characterize the pharmacokinetic interactions of mipomersen sodium with simvastatin and ezetimibe. Another aim was to evaluate the ability of mipomersen sodium to inhibit major cytochrome P450 (CYP) isoenzymes in vitro. METHODS: In a phase I clinical study, ten healthy subjects per cohort received a single oral dose of simvastatin 40 mg or ezetimibe 10 mg followed by four 2-hour intravenous doses of mipomersen sodium 200 mg over an 8-day period, with simvastatin 40 mg or ezetimibe 10 mg being administered again with the last dose of mipomersen sodium. Mipomersen sodium pharmacokinetic profiles were assessed following the first dose (mipomersen sodium alone) and the last dose (mipomersen sodium in combination with simvastatin or ezetimibe). Plasma samples for measurement of simvastatin, simvastatin acid, and free and total ezetimibe concentrations were collected at various timepoints following their first and last oral dosing. A comparative pharmacokinetic analysis was performed to determine if there were any effects resulting from coadministration of mipomersen sodium with these lipid-lowering drugs. In addition to the clinical pharmacokinetic analysis, the ability of mipomersen sodium to inhibit the major CYP isoform enzymes (namely CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) was evaluated in cryo-preserved human hepatocytes in vitro. RESULTS: The area under the plasma concentration-time curve (AUC) from 0 to 24 hours (AUC(24)), maximum plasma concentration and apparent elimination half-life values of mipomersen sodium were similar when administered alone and in combination with oral simvastatin or oral ezetimibe. The 90% confidence intervals of the geometric least squares means ratios (%Reference) of the mipomersen sodium AUC(24) values were 93.6, 107 when administered together with simvastatin, and 92.4, 111 when administered with ezetimibe. Therefore, there were no large deviations outside the default no-effect boundaries (80-125%) for total exposure (the AUC) of mipomersen sodium in combination with either simvastatin or ezetimibe. Similarly, large deviations outside the default no-effect boundaries were not observed for simvastatin, simvastatin acid, or free and total ezetimibe exposure in combination with mipomersen sodium. In cryo-preserved human hepatocytes, mipomersen sodium exhibited no cytotoxicity. Significant cell uptake was demonstrated by analysing cell-associated concentrations of mipomersen sodium. All evaluated enzyme activities had <10% inhibition at tested concentrations up to 800 microg/mL (approximately 100 micromol/L) of mipomersen sodium, and dose-dependent inhibition was not observed. Therefore, mipomersen sodium is not considered an inhibitor of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 enzyme activities. CONCLUSIONS: These data provide evidence that mipomersen sodium exhibits no clinically relevant pharmacokinetic interactions with the disposition and clearance of simvastatin or ezetimibe, and vice versa. Moreover, mipomersen sodium does not inhibit any of the major CYP enzymes that were evaluated. Taken together, the results from this study support the use of mipomersen sodium in combination with oral lipid-lowering agents.

Potent reduction of apolipoprotein B and low-density lipoprotein cholesterol by short-term administration of an antisense inhibitor of apolipoprotein B.

BACKGROUND: Apolipoprotein B (apoB) is an important structural component of low-density lipoprotein cholesterol (LDL-C) and plays a key role in LDL-C transport and removal. Reduction in apoB synthesis is expected to reduce circulating LDL-C, a proven risk factor of cardiovascular disease. In the present study, we describe the outcome of the first-in-humans study on the safety and efficacy of an antisense oligonucleotide inhibitor of apoB. METHODS AND RESULTS: This study was a double-blind, randomized, placebo-controlled, dose-escalation investigation conducted at a single site in 36 volunteers with mild dyslipidemia. The study utilized an initial single dose of 50 to 400 mg of ISIS 301012, a 20-mer oligonucleotide, followed by a 4-week multiple-dosing regimen with the same assigned dose. Safety was assessed by the incidence, severity, and relationship of adverse events to dose. Efficacy was determined by changes in serum apoB and LDL-C relative to baseline and placebo. The most common adverse event was erythema at the injection site (21 of 29 subjects). ApoB was reduced by a maximum of 50% (P=0.002) from baseline in the 200-mg cohort. This decrease in apoB coincided with a maximum 35% reduction of LDL-C (P=0.001). LDL-C and apoB remained significantly below baseline (P<0.05) up to 3 months after the last dose. CONCLUSIONS: Administration of an antisense oligonucleotide to human apoB resulted in a significant, prolonged, and dose-dependent reduction in apoB and LDL-C. Although injection-site reactions were common, adherence to protocol was unaffected.

A randomized, double-masked, placebo-controlled study of alicaforsen, an antisense inhibitor of intercellular adhesion molecule 1, for the treatment of subjects with active Crohn's disease.

BACKGROUND & AIMS: The aim of this study was to compare the safety and efficacy of alicaforsen, a first-generation antisense inhibitor of intercellular adhesion molecule 1, with placebo in subjects with active Crohn's disease, a disorder in which intercellular adhesion molecule 1 is overexpressed. METHODS: In 2 identical double-masked, placebo-controlled studies, 331 subjects with active Crohn's disease were treated with either alicaforsen (221 subjects) or placebo (110 subjects) administered via 2-hour intravenous infusion 3 times a week for 4 weeks. Patients then returned for follow-up every 2 weeks. The primary end point was clinical remission by week 12. Secondary end points included clinical response and remission in relation to previous use of other biologics including tumor necrosis factor-alpha antagonists and presence of fistulous disease. RESULTS: The results, whether combined or analyzed individually, failed to demonstrate statistical significance as a measure of its primary outcome (alicaforsen 33.9% vs placebo 34.5%; P = .89). In addition, no statistical differences in response were observed between alicaforsen and placebo in subjects who were previously treated with anti-tumor necrosis factor-alpha therapy or had baseline fistulizing disease. There were no significant differences in adverse events from placebo apart from a higher infusion reaction rate. CONCLUSIONS: In the subject population studied, alicaforsen failed to demonstrate efficacy in any of its primary outcome measures. Alicaforsen was well-tolerated.

Efficacy and safety of mipomersen, an antisense inhibitor of apolipoprotein B, in hypercholesterolemic subjects receiving stable statin therapy.

OBJECTIVES: The aim of this study was to evaluate the efficacy and safety of mipomersen in hypercholesterolemic subjects taking stable statin therapy. BACKGROUND: Mipomersen is an apolipoprotein (apo) B synthesis inhibitor that has demonstrated significant reductions in apo B and low-density lipoprotein (LDL) cholesterol in Phase 1 clinical trials in healthy volunteers. METHODS: A randomized, placebo-controlled, dose-escalation Phase 2 study was designed to evaluate the effects of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Seventy-four subjects were enrolled sequentially into 1 of 6 dose cohorts at a 4:1 (active/placebo) ratio. Subjects received 7 doses of 30 to 400 mg over 5 weeks in the first 5 cohorts and 15 doses of 200 mg over 13 weeks in the sixth cohort. Pre-specified end points included percentage change from baseline in apo B and LDL cholesterol. Safety was assessed with laboratory test results and by the incidence and severity of adverse events. RESULTS: The apo B and LDL cholesterol were reduced by 19% to 54% and 21% to 52%, respectively, at doses of 100 mg/week mipomersen and higher in the 5-week treatment cohorts. Efficacy seemed to increase upon treatment for 13 weeks at a dose of 200 mg/week. Injection site reactions (mild to moderate erythema [90%]) and hepatic transaminase increases (17%) were the most common adverse events, leading to discontinuation in 2 subjects and 1 subject, respectively. In the 13-week treatment cohort, 5 of 10 subjects (50%) had elevations >or=3x the upper limit of normal, 4 of which persisted on 2 consecutive occasions. CONCLUSIONS: Mipomersen might hold promise for treatment of patients not reaching target LDL cholesterol levels on stable statin therapy. Further studies are needed to address the mechanisms and clinical relevance of transaminase changes after mipomersen administration. (Dose-Escalating Safety Study in Subjects on Stable Statin Therapy; NCT00231569).

Cross-species comparison of in vivo PK/PD relationships for second-generation antisense oligonucleotides targeting apolipoprotein B-100.

The in vivo pharmacokinetics/pharmacodynamics of 2'-O-(2-methoxyethyl) (2'-MOE) modified antisense oligonucleotides (ASOs), targeting apolipoprotein B-100 (apoB-100), were characterized in multiple species. The species-specific apoB antisense inhibitors demonstrated target apoB mRNA reduction in a drug concentration and time-dependent fashion in mice, monkeys, and humans. Consistent with the concentration-dependent decreases in liver apoB mRNA, reductions in serum apoB, and LDL-C, and total cholesterol were concurrently observed in animal models and humans. Additionally, the long duration of effect after cessation of dosing correlated well with the elimination half-life of 2'-MOE modified apoB ASOs studied in mice (t(1/2) congruent with 20 days) and humans (t(1/2) congruent with 30 days) following parental administrations. The plasma concentrations of ISIS 301012, observed in the terminal elimination phase of both mice and monkeys were in equilibrium with liver. The partition ratios between liver and plasma were similar, approximately 6000:1, across species, and thus provide a surrogate for tissue exposure in humans. Using an inhibitory E(max) model, the ASO liver EC(50s) were 101+/-32, 119+/-15, and 300+/-191 microg/g of ASO in high-fat-fed (HF) mice, transgenic mice containing the human apoB transgene, and monkeys, respectively. The estimated liver EC(50) in man, extrapolated from trough plasma exposure, was 81+/-122 microg/g. Therefore, extraordinary consistency of the exposure-response relationship for the apoB antisense inhibitor was observed across species, including human. The cross-species PK/PD relationships provide confidence in the use of pharmacology animal models to predict human dosing for second-generation ASOs targeting the liver.

Partial liquid ventilation in adult patients with acute respiratory distress syndrome.

RATIONALE: Despite recent clinical trials demonstrating improved outcome in acute respiratory distress syndrome (ARDS), mortality remains high. Partial liquid ventilation (PLV) using perfluorocarbons has been shown to improve oxygenation and decrease lung injury in various animal models. OBJECTIVE: To determine if PLV would have an impact on outcome in patients with ARDS. METHODS: Patients with ARDS were randomized to (1) conventional mechanical ventilation (CMV; n=107), (2) "low-dose" perfluorocarbon (10 ml/kg; n=99), and (3) "high-dose" perfluorocarbon (20 ml/kg; n=105). Patients in all three groups were ventilated using volume ventilation, Vt or= 0.5, and positive end-expiratory pressure >or= 13 cm H(2)O. RESULTS: The 28-d mortality in the CMV group was 15%, versus 26.3% in the low-dose (p=0.06) and 19.1% in the high-dose (p=0.39) PLV groups. There were more ventilator-free days in the CMV group (13.0+/-9.3) compared with both the low-dose (7.4+/-8.5; p<0.001) and high-dose (9.9+/-9.1; p=0.043) groups. There were more pneumothoraces, hypoxic episodes, and hypotensive episodes in the PLV patients. CONCLUSIONS: PLV at both high and low doses did not improve outcome in ARDS compared with CMV and cannot be recommended for patients with ARDS.