The Disposition and Metabolism of Bempedoic Acid, a Potent Inhibitor of ATP Citrate Lyase, in Healthy Human Subjects.

The disposition and metabolism of bempedoic acid, a selective inhibitor of ATP citrate lyase, were examined in healthy male subjects. After a single administration of [14C] bempedoic acid (240 mg, 113 µCi) oral solution, mean concentrations of total radioactivity in plasma as a function of time indicated absorption was rapid with peak concentrations achieved at 1 hour after dose administration. Radioactivity was decreased in a multiexponential fashion with an estimated elimination half-life of 26.0 hours. Radiolabeled dose was predominantly recovered in urine (62.1% of dose) and a smaller amount in feces (25.4% of dose). Bempedoic acid was extensively metabolized with 1.6%-3.7% of dose excreted unchanged in urine and feces combined. Overall, the major clearance route of bempedoic acid is metabolism by uridine 5'-diphosphate glucuronosyltransferases. Metabolism in hepatocyte cultures of human and nonclinical species were generally in agreement with clinical metabolite profiles. Pooled plasma samples were characterized by the presence of bempedoic acid (ETC-1002), which accounted for 59.3% of total plasma radioactivity, ESP15228 (M7; a reversible keto metabolite of bempedoic acid), and their respective glucuronide conjugates. The acyl glucuronide of bempedoic acid (M6) represented 23%-36% of radioactivity in plasma and accounted for approximately 37% of dose excreted in urine. In feces, the majority of radioactivity was associated with a co-eluting mixture of a carboxylic acid metabolite of bempedoic acid (M2a), a taurine conjugate of bempedoic acid (M2c), and hydroxymethyl-ESP15228 (M2b), which collectively accounted for 3.1%-22.9% of bempedoic acid dose across subjects. SIGNIFICANCE STATEMENT: This study characterizes the disposition and metabolism of bempedoic acid, an inhibitor of ATP citrate lyase for hypercholesterolemia. This work provides further understanding of bempedoic acid clinical pharmacokinetics and clearance pathways in adult subjects.

Population pharmacokinetic and pharmacokinetic-pharmacodynamic modeling of bempedoic acid and low-density lipoprotein cholesterol in healthy subjects and patients with dyslipidemia.

Population pharmacokinetics (popPK) of bempedoic acid and the popPK/pharmacodynamic (popPK/PD) relationship between bempedoic acid concentrations and serum low-density lipoprotein cholesterol (LDL-C) from baseline were characterized. A two-compartment disposition model with a transit absorption compartment and linear elimination best described bempedoic acid oral pharmacokinetics (PK). Multiple covariates, including renal function, sex, and weight, had statistically significant effects on the predicted steady-state area under the curve. Mild (estimated glomerular filtration rate (eGFR) 60 to < 90 mL/min vs. ≥ 90 mL/min) and moderate (eGFR 30 to < 60 mL/min vs. ≥ 90 mL/min) renal impairment, female sex, low (< 70 kg vs. 70-100 kg) and high (> 100 kg vs. 70-100 kg) body weight were predicted to have a 1.36-fold (90% confidence interval (CI) 1.32, 1.41), 1.85-fold (90% CI 1.74, 2.00), 1.39-fold (90% CI 1.34, 1.47), 1.35-fold (90% CI 1.30, 1.41), and 0.75-fold (90% CI 0.72, 0.79) exposure difference relative to their reference populations, respectively. An indirect response model described changes in serum LDL-C with a model-predicted 35% maximal reduction and bempedoic acid IC50 of 3.17 µg/mL. A 28% reduction from LDL-C baseline was predicted for a steady-state average concentration of 12.5 µg/mL after bempedoic acid (180 mg/day) dosing, accounting for approximately 80% of the predicted maximal LDL-C reduction. Concurrent statin therapy, regardless of intensity, reduced the maximal effect of bempedoic acid but resulted in similar steady-state LDL-C levels. While multiple covariates had statistically significant effects on PK and LDL-C lowering, none were predicted to warrant bempedoic acid dose adjustment.

Population pharmacokinetics and exposure-response modeling and simulation for evolocumab in healthy volunteers and patients with hypercholesterolemia.

Evolocumab, a novel human monoclonal antibody, inhibits proprotein convertase subtilisin/kexin type 9, a protein that targets low-density lipoprotein-cholesterol (LDL-C) receptors for the treatment of hyperlipidemia. The primary objective of this analysis was to characterize the population pharmacokinetics (popPK) and exposure-response relationship of evolocumab to assess if dose adjustment is needed across differing patient populations. Data were pooled for 5474 patients in 11 clinical studies who received evolocumab doses of 7-420 mg at various frequencies, either intravenously or subcutaneously. Evolocumab area under concentration-time curve from 8 to 12 weeks (AUCwk8-12) was simulated for individuals using the popPK model and was used to predict the LDL-C response in relation to AUCwk8-12. Evolocumab was eliminated through nonspecific (linear) and target-mediated (nonlinear) clearance. PopPK parameters and associated variabilities of evolocumab were similar to those of other monoclonal antibodies. The exposure-response model predicted a maximal 66% reduction in LDL-C from baseline to the mean of weeks 10 and 12 for doses of evolocumab 140 mg subcutaneously every 2 weeks or 420 mg subcutaneously once monthly. After inclusion of statistically significant covariates in an uncertainty-based simulation, LDL-C reduction from baseline at the mean of weeks 10 and 12 was predicted to be within 74% to 126% of the reference patient for all simulated patient groups. Evolocumab had nonlinear pharmacokinetics. The range of responses based on intrinsic and extrinsic factors was not predicted to be sufficiently different from the reference patient to warrant evolocumab dose adjustment.

Intestinal and hepatic first-pass extraction of the 11ß-HSD1 inhibitor AMG 221 in rats with chronic vascular catheters.

1. A catheterized rat model was used to define the intestinal and hepatic components of oral bioavailability for an 11ß-HSD1 inhibitor, AMG 221. These data were integrated with standard in vivo metabolism studies to elucidate the components contributing to the oral disposition of a novel drug candidate. 2. Intestinal and hepatic extraction ratios of AMG 221 obtained using a five-catheter rat model were 0.56 and 0.32, respectively. Therefore, both intestinal and hepatic extraction contributed to the first-pass component of oral bioavailability. There was no evidence for significant gut extraction of systemically administered drug. 3. Mass balance data and in vivo metabolite characterization obtained after administration of [(14)C] AMG 221 to rat showed that AMG 221 was completely absorbed from the gut lumen following an oral dose, primarily excreted in urine and was almost completely metabolized prior to excretion. 4. Hepatic bioavailability (FH), measured in two animals at various time points after oral dose administration was somewhat variable but generally characterized by an initial reduction during the absorption phase followed by an increase during the elimination phase, consistent with hepatic distribution of AMG 221. 5. The five-catheter rat model afforded estimates of hepatic and intestinal contribution to oral bioavailability that were used with other data to define the preclinical ADME characteristics of a drug candidate.

Activity-based exposure comparisons among humans and nonclinical safety testing species in an extensively metabolized drug candidate.

1. Extensive metabolism of a drug candidate can complicate the interpretation of comparative safety and efficacy data from humans and preclinical species. 2. The 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1) inhibitor, AMG 221 underwent extensive oxidative metabolism to structurally similar but differentially active primary and secondary metabolites. Relative potency data from synthetic metabolites enabled a stepwise quantitative assessment of AMG 221 in vivo metabolism that compared relative exposure to metabolites in plasma across species and discerned which active metabolites to monitor in preclinical and clinical safety and efficacy studies. 3. Pooled plasma samples from AMG 221-dosed human subjects were profiled using high-resolution liquid chromatography-mass spectrometry (LC-MS) with a mass-defect-filter. The most abundant peak, M1 accounted for 47%-59% of peaks followed by AMG 221 at 27%-40%. Other metabolites were each less than 7%. Activity-normalized data indicated both M1 and AMG 221 should be monitored to assist pharmacokinetic-pharmacodynamic (PK-PD) modeling. 4. Rat and dog area under the plasma concentration time curve (AUC) exposures to M1 at preclinical no observable adverse effect level (NOAEL) doses were 2-42-fold higher than human, indicating M1 was not a disproportionate metabolite, as defined by International Committee on Harmonization (ICH) M3(R2) guidance. 5. Development decisions regarding active metabolite monitoring and potentially disproportionate metabolites in extensively metabolized drug candidates are enabled by metabolite synthesis and liquid chromatography high-resolution mass spectrometry (LC-HRMS)-based assessment of potency-normalized plasma metabolite AUCs.

Phase 1, Single- and Multiple-Ascending-Dose, Food-Effect, and East Asian Subject Studies to Assess the Pharmacokinetics, Safety, and Tolerability of Bempedoic Acid, a Selective Inhibitor of Adenosine Triphosphate Citrate Lyase.

Bempedoic acid is an adenosine triphosphate citrate lyase inhibitor that lowers low-density lipoprotein cholesterol by inhibiting cholesterol synthesis and upregulating hepatic low-density lipoprotein receptor expression. After oral dosing, bempedoic acid was readily absorbed, attaining maximum concentrations with a median time of 3.5 hours, and may be taken without regard to food. Steady-state oral pharmacokinetics in healthy adults receiving bempedoic acid at the approved 180 mg/day dose were characterized by mean maximum concentration of 20.6 µg/mL, area under the concentration-time curve over 24 hours of 289 µg·h/mL, and elimination half-life of 21.1 hours. Multiple-dose pharmacokinetics were linear at bempedoic acid doses of 120-220 mg/day. Circulating concentrations of the active metabolite ESP15228 were 18.0% of bempedoic acid concentrations on average. Comparisons of bempedoic acid 180 mg/day pharmacokinetics after single and multiple dosing revealed no clinically meaningful differences between Japanese, Chinese, and Western subjects. Mean estimates of bempedoic acid elimination half-life in Japanese (25.2 hours) and Chinese (20.0 hours) subjects were comparable to Western subjects (23.9 hours) following 14 days of once-daily dosing. Bempedoic acid was generally safe and well tolerated up to a dose of 220 mg/day across the study populations described herein.

Physiologically Based Pharmacokinetic Model Development and Verification for Bioequivalence Testing of Bempedoic Acid Oral Suspension and Reference Tablet Formulation.

The bioequivalence of bempedoic acid oral suspension and commercial immediate release (IR) tablet formulations were assessed using a physiologically based pharmacokinetic (PBPK) model. The mechanistic model, developed from clinical mass balance results and in vitro intrinsic solubility, permeability, and dissolution data, was verified against observed clinical pharmacokinetics (PK) results. Model inputs included a fraction of a dose in solution (0.01%), viscosity (118.8 cps), and median particle diameter (50 µm) for the suspension and particle diameter (36.4 µm) for IR tablets. Dissolution was determined in the relevant media (pH 1.2-6.8) in vitro. Model simulations of bioequivalence predicted oral suspension (test) to IR tablet (reference) geometric mean ratio estimates of 96.9% (90% confidence interval [CI]: 92.6-101) for maximum concentration and 98.2% (90% CI: 87.3-111) for the area under the concentration-time curve. Sensitivity analyses showed gastric transit time had a minor impact on model predictions. Oral suspension biopharmaceutical safe space was defined by extremes of particle size and the percent of bempedoic acid in solution. PBPK model simulations predicted that the rate and extent of bempedoic acid absorption are unlikely to exhibit clinically meaningful differences when dosed as an oral suspension compared with an IR tablet without requiring a clinical bioequivalence study in adults.

Regiospecific and stereospecific triangulation of the structures of metabolites formed by sequential metabolism at multiple prochiral centers.

Structures of in vivo secondary metabolites of a norbornane-containing drug candidate with multiple prochiral centers were triangulated, in a regio- and stereospecific fashion, using in vitro metabolism data from synthetic primary metabolites and in vivo metabolism data from the separate administration of a radiolabeled primary metabolite, [(14)C]-(S)-2-((1R,2S,4R,5S)-5-hydroxybicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one (M1). A mass balance study on the 11ß hydroxysteroid dehydrogenase type 1 enzyme inhibitor [(14)C]-(S)-2-((1S,2S,4R)-bicyclo[2.2.1]heptan-2-ylamino)-5-isopropyl-5-methylthiazol-4(5H)-one (AMG 221) in rats was dosed at 2 mg/kg. Radioactivity was excreted mainly in urine. Metabolites of AMG 221 were quantified by high-performance liquid chromatography with radiometric detection and characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS). LC-MS/MS revealed at least 38 metabolites. Seven monohydroxylated metabolites mediated formation of the other 31 metabolites. Twenty-eight metabolites were identified regio- and stereo-specifically. Little parent drug was observed in urine or feces. Monohydroxy metabolite M1 was the major metabolite comprising 17 to 24% of excreted dose, and seven monohydroxy metabolites comprised 29 (male) and 37% (female) of dose. Of 11 quantifiable isobaric dihydroxy metabolites that comprised 8.3 (male) and 24% (female) of dose, 10 were identified regio- and stereospecifically by triangulation. A single trihydroxy metabolite comprised approximately 10% of dose. Complex secondary metabolism of drugs with multiple prochiral centers can be elucidated in a regio- and stereospecific fashion without NMR through synthesis and in vitro and in vivo studies on the metabolism of chiral primary oxidation products.

Predicting the drug interaction potential of AMG 853, a dual antagonist of the D-prostanoid and chemoattractant receptor-homologous molecule expressed on T helper 2 cells receptors.

2-(4-(4-(tert-Butylcarbamoyl)-2-(2-chloro-4-cyclopropylphenylsulfonamido)phenoxy)-5-chloro-2-fluorophenyl)acetic acid (AMG 853) is an orally bioavailable and potent dual antagonist of the D-prostanoid and chemoattractant receptor-homologous molecule expressed on T helper 2 cells receptors. The drug interaction potential of AMG 853, both as a victim and a perpetrator, was investigated using in vitro, in silico, and in vivo methodologies. Experiments in human liver microsomes (HLM) and recombinant enzymes identified CYP2C8, CYP2J2, and CYP3A as well as multiple UDP-glucuronosyltransferase isoforms as being responsible for the metabolic clearance of AMG 853. With use of HLM and selective probe substrates, both AMG 853 and its acyl glucuronide metabolite (M1) were shown to be inhibitors of CYP2C8. AMG 853 and M1 did not inhibit any of the other cytochrome P450 isoforms tested, and AMG 853 exhibited minimal enzyme induction properties in human hepatocytes cultures. In light of the in vitro findings, modeling and simulation approaches were used to examine the potential for ketoconazole (a CYP3A inhibitor) to inhibit the metabolism of AMG 853 as well as for AMG 853 to inhibit the metabolism of paclitaxel, rosiglitazone, and montelukast, commonly used substrates of CYP2C8. A weak and clinically insignificant drug interaction (area under the drug concentration-time curve (AUC)(i)/AUC <2) was predicted between ketoconazole and AMG 853. No drug interactions were predicted for AMG 853 and paclitaxel, rosiglitazone, or montelukast. Finally, administration of AMG 853 to healthy human subjects in clinical trials in the presence or absence of ketoconazole confirmed that AMG 853 is unlikely to be involved in clinically significant drug interactions.

A proprotein convertase subtilisin/kexin type 9 neutralizing antibody reduces serum cholesterol in mice and nonhuman primates.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates serum LDL cholesterol (LDL-C) by interacting with the LDL receptor (LDLR) and is an attractive therapeutic target for LDL-C lowering. We have generated a neutralizing anti-PCSK9 antibody, mAb1, that binds to an epitope on PCSK9 adjacent to the region required for LDLR interaction. In vitro, mAb1 inhibits PCSK9 binding to the LDLR and attenuates PCSK9-mediated reduction in LDLR protein levels, thereby increasing LDL uptake. A combination of mAb1 with a statin increases LDLR levels in HepG2 cells more than either treatment alone. In wild-type mice, mAb1 increases hepatic LDLR protein levels approximately 2-fold and lowers total serum cholesterol by up to 36%: this effect is not observed in LDLR(-/-) mice. In cynomolgus monkeys, a single injection of mAb1 reduces serum LDL-C by 80%, and a significant decrease is maintained for 10 days. We conclude that anti-PCSK9 antibodies may be effective therapeutics for treating hypercholesterolemia.

Pharmacokinetics of bempedoic acid in patients with renal impairment.

Bempedoic acid is an ATP citrate lyase inhibitor approved for the treatment of hypercholesterolemia. The objective of this phase I study was to assess the pharmacokinetics (PKs) and safety of bempedoic acid in 24 subjects with normal renal function or mild, moderate, or severe renal impairment. All subjects received a single oral bempedoic acid 180-mg dose and PK parameters were monitored for up to 23 days. Resulting estimates of area under the concentration-time curve exposure following bempedoic acid treatment were 1.5-fold, 2.2-fold, and 2.2-fold higher in subjects with mild, moderate, or severe renal impairment, respectively, compared with subjects with normal renal function. With decreases in renal function, plasma free fraction was increased up to 20.1%, whereas total and unbound clearances were decreased by 55.2% and 62.6%, respectively, in subjects with severe renal impairment relative to those with normal renal function. These observed decreases in total and unbound oral clearance in subjects with decreased renal function are not explained by the increases in free fraction and might therefore also be attributable to changes in bioavailability or intrinsic clearance. Bempedoic acid was generally well-tolerated and the incidence and type of adverse events were not affected by the degree of renal impairment. In conclusion, bempedoic acid exposures in subjects with renal impairment were increased up to approximately two-fold with no safety signals identified, consistent with findings in phase III patients with mild or moderate renal impairment. No dose adjustments are necessary for patients with mild or moderate renal impairment.

Pharmacodynamic effect of bempedoic acid and statin combinations: predictions from a dose-response model.

AIMS: Many patients are unable to achieve guideline-recommended LDL cholesterol (LDL-C) targets, despite taking maximally tolerated lipid-lowering therapy. Bempedoic acid, a competitive inhibitor of ATP citrate lyase, significantly lowers LDL-C with or without background statin therapy in diverse populations. Because pharmacodynamic interaction between statins and bempedoic acid is complex, a dose-response model was developed to predict LDL-C pharmacodynamics following administration of statins combined with bempedoic acid. METHODS AND RESULTS: Bempedoic acid and statin dosing and LDL-C data were pooled from 14 phase 1-3 clinical studies. Dose-response models were developed for bempedoic acid monotherapy and bempedoic acid-statin combinations using previously published statin parameters. Simulations were performed using these models to predict change in LDL-C levels following treatment with bempedoic acid combined with clinically relevant doses of atorvastatin, rosuvastatin, simvastatin, and pravastatin. Dose-response models predicted that combining bempedoic acid with the lowest statin dose of commonly used statins would achieve a similar degree of LDL-C lowering as quadrupling that statin dose; for example, the predicted LDL-C lowering was 54% with atorvastatin 80 mg compared with 54% with atorvastatin 20 mg + bempedoic acid 180 mg, and 42% with simvastatin 40 mg compared with 46% with simvastatin 10 mg + bempedoic acid 180 mg. CONCLUSION: These findings suggest bempedoic acid combined with lower statin doses offers similar LDL-C lowering compared with statin monotherapy at higher doses, potentially sparing patients requiring additional lipid-lowering therapies from the adverse events associated with higher statin doses.

Absence of effect of steady state bempedoic acid on cardiac repolarization: Results of a thorough QT/QTc study in healthy volunteers.

Bempedoic acid is an inhibitor of adenosine triphosphate-citrate lyase approved for use in adults with hypercholesterolemia. Nonclinical studies assessed binding to the human ether-a-go-go-related gene (hERG) potassium channel in vitro and the effect of bempedoic acid on QT/QTc in cynomolgus monkeys. A randomized, double-blind, parallel-design clinical study assessed the effects of steady-state bempedoic acid at a supratherapeutic dose (240 mg/day, 33.3% higher the180 mg/day therapeutic dose), placebo, and moxifloxacin (400 mg) in healthy subjects. In vitro binding potency for bempedoic acid to the hERG potassium channel was weak, with half-maximal inhibition (IC50 ) estimated at greater than 1000 µM (>1670-fold the bempedoic acid 180 mg/day steady-state unbound maximum concentration). In monkeys, individual rate-corrected QT intervals showed no time- or dose-dependent changes up to 100 mg/kg of bempedoic acid. In human subjects, the upper 90% confidence interval (CI) for the difference in QTc interval, corrected using Fridericia's formula (QTcF), between bempedoic acid and placebo was less than 5 msec at all time points. Concentration-QTcF analysis showed that maximum bempedoic acid concentration at steady-state was attained at a median 2.1 h postdose, and the predicted mean change (90% CI) in QTcF at the observed mean bempedoic acid concentration 2 h postdose was -0.5 (-5.0, 4.0) msec. The lower bound of the moxifloxacin 90% CI exceeded 5 msec at prespecified time points, establishing study sensitivity. Steady-state bempedoic acid at a supratherapeutic dose of 240 mg was generally well-tolerated and not associated with QTc prolongation in healthy subjects.

Influence of Renal Function on Evolocumab Exposure, Pharmacodynamics, and Safety.

We evaluated the pharmacokinetics, pharmacodynamics, and safety of evolocumab, a fully human monoclonal antibody against proprotein convertase subtilisin kexin type 9 (PCSK9), in an open-label, parallel-design study in participants with normal renal function (n = 6), severe renal impairment (RI; n = 6), or end-stage renal disease (ESRD) receiving hemodialysis (n = 6) who received a single 140-mg dose of evolocumab. The effects of evolocumab treatment on low-density lipoprotein cholesterol (LDL-C) lowering and unbound PCSK9 concentrations were similar in the normal renal function group and the renally impaired groups. Geometric mean Cmax and AUClast values in the severe RI and ESRD hemodialysis groups compared with the normal renal function group were lower but within 37% of the normal renal function group (Jonckheere-Terpstra trend test; Cmax , P = .23; AUClast , P = .22) and within 26% after adjusting for body weight (mean body weight was approximately 9% higher in the renally impaired groups compared with the normal renal function group). No correlations were observed between exposure and baseline creatinine clearance. No adverse event was determined by the investigators to be related to evolocumab, and there were no trends indicative of clinically important effects on laboratory variables or vital signs. Overall, there were no meaningful differences in evolocumab exposure, as assessed by Cmax and AUClast , in patients with severe RI and ESRD hemodialysis compared with patients with normal renal function, and LDL-C-lowering effects were similar across groups. These results support the use of evolocumab without dose adjustment in patients who have severe RI or ESRD.

2-amino-1,3-thiazol-4(5H)-ones as potent and selective 11beta-hydroxysteroid dehydrogenase type 1 inhibitors: enzyme-ligand co-crystal structure and demonstration of pharmacodynamic effects in C57Bl/6 mice.

11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) has attracted considerable attention during the past few years as a potential target for the treatment of diseases associated with metabolic syndrome. In our ongoing work on 11beta-HSD1 inhibitors, a series of new 2-amino-1,3-thiazol-4(5 H)-ones were explored. By inserting various cycloalkylamines at the 2-position and alkyl groups or spirocycloalkyl groups at the 5-position of the thiazolone, several potent 11beta-HSD1 inhibitors were identified. An X-ray cocrystal structure of human 11beta-HSD1 with compound 6d (Ki=28 nM) revealed a large lipophilic pocket accessible by substitution off the 2-position of the thiazolone. To increase potency, analogues were prepared with larger lipophilic groups at this position. One of these compounds, the 3-noradamantyl analogue 8b, was a potent inhibitor of human 11beta-HSD1 (Ki=3 nM) and also inhibited 11beta-HSD1 activity in lean C57Bl/6 mice when evaluated in an ex vivo adipose and liver cortisone to cortisol conversion assay.

Cinacalcet does not affect the activity of cytochrome P450 3A enzymes, a metabolic pathway for common immunosuppressive agents : a randomized, open-label, crossover, single-centre study in healthy volunteers.

BACKGROUND AND OBJECTIVE: Cinacalcet HCl (cinacalcet) is approved for the treatment of secondary hyperparathyroidism in subjects receiving dialysis and for the reduction of hypercalcaemia in patients with parathyroid carcinoma. The drug may also be co-administered with medications used in the renal transplantation setting, such as immunosuppressants. Cinacalcet, as well as some immunosuppressants such as ciclosporin, tacrolimus and sirolimus, is partially metabolized by the cytochrome P450 3A enzymes (CYP3A). This study aimed to evaluate the potential inhibitory effects of cinacalcet on CYP3A activity using midazolam as a probe substrate in healthy volunteers. METHODS: In this randomized, open-label, crossover, two-treatment, two-period, single-centre study, 12 healthy volunteers received either oral cinacalcet 90 mg once daily for 5 days plus a single oral dose of midazolam 2 mg on day 5, or a single oral dose of midazolam 2 mg on day 1. Following a 10-day washout period, subjects received the alternate treatment. Blood samples were collected predose and at selected time points up to 24 hours after dosing with midazolam for measurement of midazolam pharmacokinetic parameters. RESULTS: Eleven subjects completed the study. Mean (standard deviation) midazolam maximum plasma concentrations (C(max)) and area under the plasma concentration-time curve from time zero to infinity (AUC(infinity)) were 9.31 (3.09) ng/mL and 24.1 (7.7) ng . h/mL, respectively, when administered in combination with cinacalcet, compared with 9.76 (2.81) ng/mL and 22.8 (6.1) ng . h/mL when administered alone. The mean geometric ratios (90% confidence interval) were 0.95 (0.84, 1.06) and 1.05 (0.95, 1.16) for C(max) and AUC(infinity), respectively. All adverse events were mild to moderate in severity, and consistent with the safety profile of cinacalcet. CONCLUSION: Once-daily administration of cinacalcet did not alter the pharmacokinetics of midazolam relative to administration of midazolam alone. These data suggest that cinacalcet administration does not affect CYP3A activity, and thus would not have an effect on any drug eliminated via CYP3A, including some commonly used immunosuppressant therapies.

Clinical Pharmacokinetics and Pharmacodynamics of Evolocumab, a PCSK9 Inhibitor.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases plasma low-density lipoprotein cholesterol (LDL-C) by decreasing expression of the LDL receptor on hepatic cells. Evolocumab is a human monoclonal immunoglobulin G2 that binds specifically to human PCSK9 to reduce LDL-C. Evolocumab exhibits nonlinear kinetics as a result of binding to PCSK9. Elimination is predominantly through saturable binding to PCSK9 at lower concentrations and a nonsaturable proteolytic pathway at higher concentrations. The effective half-life of evolocumab is 11-17 days. The pharmacodynamic effects of evolocumab on PCSK9 are rapid, with maximum suppression within 4 h. At steady state, peak reduction of LDL-C occurs approximately 1 week after a subcutaneous dose of 140 mg every 2 weeks (Q2W) and 2 weeks after a subcutaneous dose 420 mg once monthly (QM), and returns towards baseline over the dosing interval. In several clinical studies, these doses of evolocumab reduced LDL-C by approximately 55-75% compared with placebo. Evolocumab also reduced lipoprotein(a) [Lp(a)] levels and improved those of other lipids in clinical studies. No clinically meaningful differences in pharmacodynamic effects on LDL-C were observed in adult subjects regardless of mild/moderate hepatic impairment, renal impairment or renal failure, body weight, race, sex, or age. No clinically meaningful differences were observed for the pharmacodynamic effects of evolocumab on LDL-C between patients who received evolocumab alone or in combination with a statin, resulting in additional lowering of LDL-C when evolocumab was combined with a statin. No dose adjustment is necessary based on patient-specific factors or concomitant medication use.

Comparison of LDL-C Reduction Using Different Evolocumab Doses and Intervals: Biological Insights and Treatment Implications.

BACKGROUND: The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor evolocumab reduces low-density lipoprotein cholesterol (LDL-C) and the risk of cardiovascular events. OBJECTIVES: To compare LDL-C reduction using evolocumab 140 mg once every 2 weeks (Q2W) or 420 mg monthly (QM) versus lower doses (70 mg Q2W or 280 mg QM) or placebo. METHODS: Patients received evolocumab 70 or 140 mg Q2W, 280 or 420 mg QM, or placebo Q2W or QM in two 12-week phase 2 studies: one with and one without statins. Changes from baseline in LDL-C were compared across Q2W doses and across QM doses. RESULTS: The analysis included 741 patients. Mean (95% confidence interval [CI]) reduction in LDL-C across Q2W visits through week 12 was 63.0% (60.3% to 65.7%) for evolocumab 140 mg Q2W, compared to 41.3% (38.6% to 44.0%) for 70 mg Q2W and 1.9% (4.6% reduction to 0.8% increase) for placebo Q2W (each P < .001 vs 140 mg Q2W), and 62.7% (60.1% to 65.3%) for 420 mg QM, compared to 55.5% (52.9% to 58.0%) for 280 mg QM and 2.5% (5.1% reduction to 0.1% increase) for placebo QM (each P < .001 vs 420 mg QM). Similar results were observed at the mean of weeks 10 and 12. In a subgroup (n = 151) with weekly assessments from weeks 8 to 12, mean (95% CI) peak effect on LDL-C reduction was 72.8% (67.7% to 77.9%) for 140 mg Q2W and 69.0% (63.6% to 74.3%) for 420 mg QM. Trough effect at week 12 underestimated LDL-C reduction. Median peak-trough variability was 20.5%, 21.1%, 31.9%, and 35.1% for evolocumab 140 mg Q2W, 420 mg QM, 70 mg Q2W, and 280 mg QM, respectively. CONCLUSION: Evolocumab 140 mg Q2W and 420 mg QM yielded similar LDL-C reduction. These doses sustained maximal LDL-C reduction, resulting in greater stability in LDL-C reduction over the dosing interval compared to lower doses. These results support evolocumab doses of either 140 mg Q2W or 420 mg QM.

Evolution of a highly selective and potent 2-(pyridin-2-yl)-1,3,5-triazine Tie-2 kinase inhibitor.

Inhibition of angiogenesis is a promising and clinically validated approach for limiting tumor growth and survival. The receptor tyrosine kinase Tie-2 is expressed almost exclusively in the vascular endothelium and is required for developmental angiogenesis and vessel maturation. However, the significance of Tie-2 signaling in tumor angiogenesis is not well understood. In order to evaluate the therapeutic utility of inhibiting Tie-2 signaling, we developed a series of potent and orally bioavailable small molecule Tie-2 kinase inhibitors with selectivity over other kinases, especially those that are believed to be important for tumor angiogenesis. Our earlier work provided pyridinyl pyrimidine 6 as a potent, nonselective Tie-2 inhibitor that was designed on the basis of X-ray cocrystal structures of KDR inhibitors 34 (triazine) and 35 (nicotinamide). Lead optimization resulted in pyridinyl triazine 63, which exhibited >30-fold selectivity over a panel of kinases, good oral exposure, and in vivo inhibition of Tie-2 phosphorylation.

Alkynylpyrimidine amide derivatives as potent, selective, and orally active inhibitors of Tie-2 kinase.

The recognition that aberrant angiogenesis contributes to the pathology of inflammatory diseases, cancer, and myocardial ischemia has generated considerable interest in the molecular mechanisms that regulate blood vessel growth. The receptor tyrosine kinase Tie-2 is expressed primarily by vascular endothelial cells and is critical for embryonic vasculogenesis. Interference with the Tie-2 pathway by diverse blocking agents such as soluble Tie-2 receptors, anti-Tie-2 intrabodies, anti-Ang-2 antibodies, and peptide-Fc conjugates has been shown to suppress tumor growth in xenograft studies. An alternative strategy for interfering with the Tie-2 signaling pathway involves direct inhibition of the kinase functions of the Tie-2 receptor. Herein we describe the development of alkynylpyrimidine amide derivatives as potent, selective, and orally available ATP-competitive inhibitors of Tie-2 autophosphorylation.