Cerivastatin (BAY w 6228): A Novel HMG-CoA Reductase Inhibitor

The paracaspase MALT1 controls cholesterol homeostasis in glioblastoma stem-like cells through lysosome proteome shaping

Glioblastoma stem-like cells (GSCs) compose a tumor-initiating and -propagating population remarkably vulnerable to variation in the stability and integrity of the lysosomal compartment. Previous work has shown that the expression and activity of the paracaspase MALT1 control GSC viability via lysosome abundance. However, the underlying mechanisms remain elusive. By combining RNA sequencing (RNA-seq) with proteome-wide label-free quantification, we now report that MALT1 repression in patient-derived GSCs alters the homeostasis of cholesterol, which accumulates in late endosomes (LEs)-lysosomes. This failure in cholesterol supply culminates in cell death and autophagy defects, which can be partially reverted by providing exogenous membrane-permeable cholesterol to GSCs. From a molecular standpoint, a targeted lysosome proteome analysis unraveled that Niemann-Pick type C (NPC) lysosomal cholesterol transporters are diluted when MALT1 is impaired. Accordingly, we found that NPC1/2 inhibition and silencing partially mirror MALT1 loss-of-function phenotypes. This supports the notion that GSC fitness relies on lysosomal cholesterol homeostasis.

Statin Action Targets Lipid Rafts of Cell Membranes: GIXD/PM-IRRAS Investigation of Langmuir Monolayers

Lipid rafts are condensed regions of cell membranes rich in cholesterol and sphingomyelin, which constitute the target for anticholesterolemic drugs - statins. In this work, we use for the first time a combined grazing-incidence X-ray diffraction (GIXD)/polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS)/Brewster angle microscopy (BAM) approach to show the statin effect on model lipid rafts and its components assembled in Langmuir monolayers at the air-water interface. Two representatives of these drugs, fluvastatin (FLU) and cerivastatin (CER), of different hydrophobicity were chosen, while cholesterol (Chol) and sphingomyelin (SM), and their 1:1 mixture were selected to form condensed monolayers of lipid rafts. The effect of statins on the single components of lipid rafts indicated that both the hydrophobicity of the drugs and the organization of the layer determined the drug-lipid interaction. For cholesterol monolayers, only the most hydrophobic CER was effectively changing the film structure, while for the less organized sphingomyelin, the biggest effect was observed for FLU. This drug affected both the polar headgroup region as shown by PM-IRRAS results and the 2D crystalline structure of the SM monolayer as evidenced by GIXD. Measurements performed for Chol/SM 1:1 models proved also that the statin effect depends on the presence of Chol-SM complexes. In this case, the less hydrophobic FLU was not able to penetrate the binary layer at all, while exposure to the hydrophobic CER resulted in the phase separation and formation of ordered assemblies. The changes in the membrane properties were visualized by BAM images and GIXD patterns and confirmed by thermodynamic parameters of hysteresis in the Langmuir monolayer compression-decompression experiments.

Clinical-pharmacological strategies to assess drug interaction potential during drug development

Drug interactions in patients receiving multiple drug regimens are a constant concern for the clinician. With the increased availability of new drugs and their concomitant use with other drugs, there has been a rise in the potential for adverse drug interactions as demonstrated by the recent withdrawals of newly marketed drugs because of unacceptable interaction profiles. Therefore, the interaction potential of a new compound has to be assessed in detail, starting with preclinical in vitro and in vivo studies at candidate selection and continuously followed up through preclinical and clinical development. Since formal in vivo studies of all possible drug interactions are neither practicable nor suggestive, a careful selection of a limited number of drug combinations to be investigated in vivo during the development phase is indicated. Based on knowledge of pharmacokinetic and biopharmaceutical properties, a well balanced link between in vitro investigations and carefully selected in vivo interaction studies allows full assessment of the potential of a new drug to cause clinically relevant pharmacokinetic drug-drug interactions, prediction of a lack of interactions and derivation of the proper dose recommendations. Clinical pharmacology plays a number of key roles within the process of collecting information on drug interactions during preclinical and clinical development: addressing issues and/or favourable properties to be expected, thus contributing to the scientific assessment of development potential; setting up a rational in vivo drug-drug interaction programme; performing early mechanistic studies to link in vitro with in vivo information (employing 'cocktail' approaches if possible); reviewing co-medication sections for clinical trials; and conducting labelling-oriented interaction studies, after proof of concept. The fact that interactions can occur between various active substances should by itself be a conclusive argument against unnecessary polypharmacy. Prescribing fewer drugs on a rational basis can reduce the risk of adverse effects secondary to drug interactions and may help to improve the quality of drug treatment and to save costs.

Safety profiles for the HMG-CoA reductase inhibitors: treatment and trust

Hypercholesterolaemia is a chronic condition that often requires life-long treatment, making the safety of lipid-lowering drugs a critical issue. 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors ('statins') are commonly used as the pharmacotherapeutic treatment of choice for patients with hypercholesterolaemia. These agents have consistently demonstrated a positive safety and tolerability profile, and are recommended by the US National Cholesterol Education Program guidelines and by the European Joint Task Force for Prevention of Coronary Heart Disease to be used after, or in addition to, a first-line approach with diet. Several large-scale clinical trials have shown HMG-CoA reductase inhibitors to be efficacious and well tolerated, and to be associated with a low rate of treatment withdrawal due to adverse events. These studies included mortality and morbidity end-points, and comprised both primary- and secondary-prevention trials. Hepatic, renal and muscular systems are rarely affected during HMG-CoA reductase inhibitor therapy and the few drug interactions that can occur with concomitantly administered drugs are well documented. There is no conclusive evidence linking HMG-CoA reductase inhibitors to the development of cancer in humans. In long term studies with various HMG-CoA reductase inhibitors, there was no increase in cancer rates compared with placebo. Thus, it can be concluded that HMG-CoA reductase inhibitors are well tolerated, effective treatments for hypercholesterolaemia.

Cerivastatin: a review of its pharmacological properties and therapeutic efficacy in the management of hypercholesterolaemia

Cerivastatin is an HMG-CoA reductase inhibitor used for the treatment of patients with hypercholesterolaemia. The lipid-lowering efficacy of cerivastatin has been demonstrated in a number of large multicentre, randomised clinical trials. Earlier studies used cerivastatin at relatively low dosages of < or =0.3mg orally once daily, but more recent studies have focused on dosages of 0.4 or 0.8 mg/day currently recommended by the US Food and Drug Administration (FDA). Along with modest improvements in serum levels of triglycerides and high density lipoprotein (HDL)-cholesterol, cerivastatin 0.4 to 0.8 mg/day achieved marked reductions in serum levels of low density lipoprotein (LDL)-cholesterol (33.4 to 44.0%) and total cholesterol (23.0 to 30.8%). These ranges included results of a pivotal North American trial in almost 1000 patients with hypercholesterolaemia. In this 8-week study, US National Cholesterol Education Program (Adult Treatment Panel II) [NCEP] target levels for LDL-cholesterol were achieved in 84% of patients randomised to receive cerivastatin 0.8 mg/day, 73% of those treated with cerivastatin 0.4 mg/day and <10% of placebo recipients. Among patients with baseline serum LDL-cholesterol levels meeting NCEP guidelines for starting pharmacotherapy, 75% achieved target LDL-cholesterol levels with cerivastatin 0.8 mg/day. In 90% of all patients receiving cerivastatin 0.8 mg/day, LDL-cholesterol levels were reduced by 23.9 to 58.4% (6th to 95th percentile). Various subanalyses of clinical trials with cerivastatin indicate that the greatest lipid-lowering response can be expected in women and elderly patients. Cerivastatin is generally well tolerated and adverse events have usually been mild and transient. The overall incidence and nature of adverse events reported with cerivastatin in clinical trials was similar to that of placebo. The most frequent adverse events associated with cerivastatin were headache, GI disturbances, asthenia, pharyngitis and rhinitis. In the large pivotal trial, significant elevations in serum levels of creatine kinase and transaminases were reported in a small proportion of patients receiving cerivastatin but not in placebo recipients. As with other HMG-CoA reductase inhibitors, rare reports of myopathy and rhabdomyolysis have occurred with cerivastatin, although gemfibrozil or cyclosporin were administered concomitantly in most cases. Postmarketing surveillance studies in the US have been performed. In 3 mandated formulary switch conversion studies, cerivastatin was either equivalent or superior to other HMG-CoA reductase inhibitors, including atorvastatin, in reducing serum LDL-cholesterol levels or achieving NCEP target levels. Pharmacoeconomic data with cerivastatin are limited, but analyses conducted to date in the US and Italy suggest that cerivastatin compares favourably with other available HMG-CoA reductase inhibitors in terms of its cost per life-year gained.

CONCLUSION

Cerivastatin is a well tolerated and effective lipid-lowering agent for patients with hypercholesterolaemia. When given at dosages currently recommended by the FDA in the US, cerivastatin achieves marked reductions in serum levels of LDL-cholesterol, reaching NCEP target levels in the vast majority of patients. Thus, cerivastatin provides a useful (and potentially cost effective) alternative to other currently available HMG-CoA reductase inhibitors as a first-line agent for hypercholesterolaemia.

Clinical pharmacokinetics of cerivastatin

Cerivastatin sodium, a novel statin, is a synthetic, enantiomerically pure, pyridine derivative that effectively reduces serum cholesterol levels at microgram doses. Cerivastatin is readily and completely absorbed from the gastrointestinal tract, with plasma concentrations reaching a peak 2 to 3 hours postadministration followed by a monoexponential decay with an elimination half-life (t1/2beta) of 2 to 3 hours. Cerivastatin pharmacokinetics are linear: maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) are proportional to the dose over the range of 0.05 to 0.8 mg. No accumulation is observed on repeated administration. Cerivastatin interindividual variability is described by coefficients of variation of approximately 30 to 40% for its primary pharmacokinetic parameters AUC, Cmax and t1/2beta. The mean absolute oral bioavailability of cerivastatin is 60% because of presystemic first-pass effects. Its pharmacokinetics are not influenced by concomitant administration of food nor by the time of day at which the dose is given. Age, gender, ethnicity and concurrent disease also have no clinically significant effects. Cerivastatin is highly bound to plasma proteins (>99%). The volume of distribution at steady state of about 0.3 L/kg indicates that the drug penetrates only moderately into tissue; conversely, preclinical studies have shown a high affinity for liver tissue, the target site of action. Cerivastatin is exclusively cleared via metabolism. No unchanged drug is excreted. Cerivastatin is subject to 2 main oxidative biotransformation reactions: demethylation of the benzylic methyl ether moiety leading to the metabolite M-1 [catalysed by cytochrome P450 (CYP) 2C8 and CYP3A4] and stereoselective hydroxylation of one methyl group of the 6-isopropyl substituent leading to the metabolite M-23 (catalysed by CYP2C8). The product of the combined biotransformation reactions is a secondary minor metabolite, M-24, not detectable in plasma. All 3 metabolites are active inhibitors of hydroxymethylglutaryl-coenzyme A reductase with a similar potency to the parent drug. Approximately 70% of the administered dose is excreted as metabolites in the faeces, and 30% in the urine. Metabolism by 2 distinct CYP isoforms renders cerivastatin relatively resistant to interactions arising from inhibition of CYP. If one of the pathways is blocked, cerivastatin can be effectively metabolised by the alternative route. In addition, on the basis of in vitro investigations, there is no evidence for either cerivastatin or its metabolites having any inducing or inhibitory activity on CYP. The apparent lack of any clinically relevant interactions with a variety of drugs commonly used by patients in the target population supports this favourable drug-drug interaction profile.

Biopharmaceutical profile of cerivastatin: a novel HMG-CoA reductase inhibitor

The biopharmaceutical properties of cerivastatin were evaluated in a series of worldwide clinico-pharmacological studies. Young healthy males aged 18-45 years were randomized to receive 0.05-0.8 mg cerivastatin orally, given either as single or multiple once-daily doses under fed or fasting conditions in the morning, with evening meal or at bedtime. Following administration, cerivastatin was rapidly and almost completely absorbed into the gastrointestinal tract (> 98%), with maximum plasma concentrations (Cmax) reached at 2-3 h post dose. The plasma concentration/time profile of the tablet is similar to an aqueous oral solution (relative bioavailability is 100%). The dose-proportionality of cerivastatin (0.05-0.8 mg) in area under the curve and Cmax showed low intra- and interindividual variability. The effect of food (single-dose studies testing administration of cerivastatin with a high-fat meal and clinical investigations in patients) or time of administration (single- and multiple-dose once-daily/twice-daily studies) had no clinically relevant effects on the pharmacokinetics of cerivastatin. Marketed tablet strengths and drug formulations from different sources were found to be bioequivalent. Cerivastatin is a noncomplicated drug with respect to its biopharmaceutical profile and bioavailability.