Pharmacokinetics and safety of golimumab in healthy Chinese subjects following a single subcutaneous administration in a randomized phase I trial.

BACKGROUND AND OBJECTIVES: Golimumab is an anti-tumor necrosis factor-α human immunoglobulin G1κ monoclonal antibody that is efficacious for the treatment of moderate to severe rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis in adults. The objective of this study was to assess the pharmacokinetic characteristics of golimumab in healthy male Chinese subjects following a single subcutaneous (SC) administration of golimumab 50 or 100 mg. The safety, tolerability, and immunogenicity of a single SC administration of golimumab in Chinese subjects were also evaluated. METHODS: This was a phase I, randomized, open-label, single-dose, single-period, single-center study. Twenty-four healthy male Chinese subjects were randomized (1:1) to receive a single SC administration of golimumab 50 or 100 mg. Serial blood samples for the measurement of serum golimumab concentrations were collected and analyzed using a validated electrochemiluminescent immunoassay method. The pharmacokinetic parameters [maximum observed serum concentration (C(max)), time to reach C(max) (t(max)), area under the serum concentration-time curve from time zero to infinity (AUC∞), and terminal half-life (t(½))] of golimumab were derived using a noncompartmental analysis. RESULTS: Following a single SC administration of golimumab 50 or 100 mg in Chinese male subjects (age 19-41 years, body weight 60-76 kg), mean ± standard deviation C(max) (3.6 ± 1.6 and 7.5 ± 1.4 µg/mL, respectively) and AUC∞ (59.8 ± 19.8 and 132.8 ± 27.0 µg·day/mL, respectively) increased in a dose-proportional manner. The median t(max) was in the range of 4.5-5.0 days, and the mean t(½) was in the range of 10.8-11.9 days. Among 24 subjects, 23 had appropriate samples for evaluation of antibodies to golimumab, and one subject (1/23, 4.3%) in the 100-mg group tested positive. Three mild adverse events were reported (infected sebaceous cyst, upper respiratory tract infection, and headache), all in the 50-mg group; none were considered to be related to the study agent. CONCLUSIONS: Golimumab exhibited linear pharmacokinetics at dose levels of 50 and 100 mg following a single SC administration in healthy Chinese subjects. Single SC administrations of golimumab 50 or 100 mg were considered to be generally well tolerated. The results from this study indicate that there are no apparent ethnic differences in the pharmacokinetics of golimumab between Chinese and Caucasian subjects.

Placebo- and amitriptyline-controlled evaluation of central nervous system effects of the NK1 receptor antagonist aprepitant and intravenous alcohol infusion at pseudo-steady state.

Recent interest in NK1 receptor antagonists has focused on a potential role in the treatment of drug addiction and substance abuse. In the present study, the potential for interactions between the NK1 receptor antagonist aprepitant and alcohol, given as an infusion at a target level of 0.65 g/L, was evaluated. Amitriptyline was included as positive control to provide an impression of the profile of central nervous system (CNS) effects. In a double-blind, randomized, placebo- and amitriptyline-controlled study, the pharmacokinetics and CNS effects of aprepitant and alcohol were investigated in 16 healthy volunteers. Cognitive and psychomotor function tests included the visual verbal learning test (VVLT), Bond and Lader visual analogue scales (VAS), digit symbol substitution test (DSST), visual pattern recognition, binary choice reaction time, critical flicker fusion (CFF), body sway, finger tapping, and adaptive tracking. Alcohol impaired finger tapping and body sway. Amitriptyline impaired DSST performance, VAS alertness, CFF, body sway, finger tapping, and adaptive tracking. No impairments were found after administration of aprepitant. Co-administration of aprepitant with alcohol was generally well tolerated and did not cause significant additive CNS effects, compared with alcohol alone. Therefore, our study found no indications for clinically relevant interactions between aprepitant and alcohol.

Comparison of the pharmacokinetics of subcutaneous ustekinumab between Chinese and non-Chinese healthy male subjects across two Phase 1 studies.

BACKGROUND AND OBJECTIVE: Ustekinumab, a human immunoglobulin G1 kappa (IgG1κ) monoclonal antibody against interleukin-12/23p40, has been reported to be significantly efficacious in treating patients with moderate-to-severe plaque psoriasis. Although the efficacy and safety of ustekinumab have been previously studied in Asian patients with psoriasis, the pharmacokinetics of ustekinumab has not been reported for Asian patients. The objective of this analysis was to compare the pharmacokinetics of ustekinumab in Chinese and non-Chinese subjects. SUBJECTS AND METHODS: Two Phase 1, open-label, single-period, inpatient/outpatient studies were conducted to evaluate the pharmacokinetics of ustekinumab following a single subcutaneous (SC) injection. In Study 1, non-Chinese healthy male subjects (n = 31) received a single SC injection of ustekinumab 90 mg. In Study 2, Chinese healthy male subjects (n = 24) were randomized (1:1) to receive a single SC injection of ustekinumab 45 mg or 90 mg. Serum ustekinumab concentrations were measured using validated immunoassays. The pharmacokinetic parameters were calculated using non-compartmental analyses. After data collection, a linear mixed model approach was used to compare the log-transformed maximum observed serum concentration (Cmax) and area under the serum concentration-time curves (AUCs) generated from the 90-mg dose groups in the two studies. The ratios of the geometric means of the Cmax and AUCs in Chinese subjects (Test) to those in non-Chinese subjects (Reference) along with the 90 % confidence intervals (CIs) were calculated. RESULTS: The mean body weight was 80.3 kg in non-Chinese (Caucasian: 77.4 %; black: 12.9 %; Asian: 0.0 %; other: 9.7 %) and 65.7 kg in Chinese subjects, with an overall mean of 74 kg. Across studies and dose groups, the median time corresponding to the Cmax (tmax) was 4.0-8.5 days, the mean terminal half-life (t½) was approximately 3 weeks, and the mean apparent volume of distribution based on the terminal phase (Vz/F) was 80.3-97.3 mL/kg. In the 90-mg groups, mean exposure parameters of ustekinumab were 1.1- to 1.3-fold higher in Chinese versus non-Chinese subjects. However, exposure parameters were not significantly different between the two study populations when individual parameters were adjusted to a subject weighing 74 kg: the 90 % CIs of the geometric mean ratios (Chinese versus non-Chinese) for weight-adjusted Cmax, AUC from time zero to time of last measurable concentration (AUClast), and AUC from time zero to infinity (AUC∞) were (0.76-1.09), (0.85-1.16) and (0.88-1.22), respectively. Ustekinumab was generally well tolerated, with no unexpected adverse events; one subject (non-Chinese) developed anti-drug antibodies to ustekinumab. CONCLUSION: The pharmacokinetics of ustekinumab were comparable between Chinese and non-Chinese healthy male subjects when exposure parameters were adjusted by subject body weight. CLINICAL TRIAL REGISTRATION: Study 1, conducted with non-Chinese subjects (March-July 2006), was completed before the 7th revision of the Declaration of Helsinki and was therefore exempt from registration under the existing guidelines. The clinical trial registration number for Study 2, conducted with Chinese subjects (October 2009-June 2010), is NCT01081704.

Pharmacokinetics and safety of sirukumab following a single subcutaneous administration to healthy Japanese and Caucasian subjects.

OBJECTIVE: Sirukumab (CNTO 136) is a human mAb with high affinity and specificity for binding to interleukin-6. This Phase 1 study evaluated the pharmacokinetics, immunogenicity, safety, and tolerability of sirukumab following a single subcutaneous (s.c.) administration in healthy male Japanese and Caucasian subjects. METHODS: Japanese and Caucasian subjects were randomized to placebo or 25, 50, or 100 mg sirukumab. Blood samples were collected to measure serum sirukumab concentration and antibodies to sirukumab. Noncompartmental analysis and population pharmacokinetic modeling were conducted to characterize sirukumab pharmacokinetics. Adverse events were monitored at each visit. RESULTS: 25 Japanese and 24 Caucasian subjects received sirukumab and were included in the pharmacokinetic evaluation. Mean Cmax and AUC0-∞of sirukumab increased in an approximately dose-proportional manner in both Japanese and Caucasian subjects. Median tmax was 3 -5 days after s.c. administration of sirukumab. Mean t1/2 was 15 -16 days in Japanese and 15 -18 days in Caucasian subjects. A one-compartment population pharmacokinetic model adequately described sirukumab pharmacokinetics following s.c. administration. The estimated population means for CL/F, V/F, and Ka were 0.54 ±0.03 l/day, 12.2 ±0.55 l, and 0.77 ±0.07 day-1, respectively. Race was not a significant covariate on CL/F or V/F. No subject was positive for antibodies to sirukumab. Adverse events were generally mild and did not appear to be dose-related or lead to study discontinuation. CONCLUSIONS: Sirukumab pharmacokinetics following subcutaneous administration was linear at doses ranging 25 -100 mg and was comparable between Japanese and Caucasian subjects. A single subcutaneous administration of 25, 50, or 100 mg sirukumab appeared to be well tolerated by both Japanese and Caucasian healthy male subjects.

Safety, tolerability and pharmacokinetics of a human anti-interleukin-13 monoclonal antibody (CNTO 5825) in an ascending single-dose first-in-human study.

AIMS: To assess the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and immunogenicity of CNTO 5825 following single-dose intravenous (i.v.) and subcutaneous (s.c.) administration in healthy and healthy atopic subjects. METHODS: Sixty-four subjects received a single dose of placebo or CNTO 5825 (0.1, 0.3, 1.0, 3.0, or 10 mg kg(-1) i.v. in a dose-escalating manner, or 3.0 mg kg(-1) s.c. in healthy subjects; and 10 mg kg(-1) i.v. in healthy atopic subjects). Subjects were observed for 96 h postadministration and followed for 16 weeks. Safety and tolerability were monitored, and serum samples were collected to measure CNTO 5825 concentrations, antibodies to CNTO 5825 and PD biomarkers. RESULTS: Most adverse events were mild to moderate in severity and considered to be unrelated to CNTO 5825, with no dose-dependent trends seen. The two serious adverse events were considered to be unrelated to CNTO 5825. After i.v. administration, CNTO 5825 exhibited linear PK, with a terminal half-life of ∼22-32 days. After a single 3 mg kg(-1) s.c. dose in healthy subjects, CNTO 5825 was absorbed into the systemic circulation with a median time to maximum serum concentration (tmax) of 5.45 days and absolute bioavailability of ∼75%. The PK profile of CNTO 5825 at 10 mg kg(-1) was similar in both healthy and healthy atopic subjects. No antibodies to CNTO 5825 were detected through week 16. In the CNTO 5825-treated healthy atopic subjects, there was a significant reduction in serum IgE and C-C motif chemokine ligand 17 (P = 0.028 and 0.068 vs. placebo, respectively). CONCLUSIONS: CNTO 5825 was well tolerated, had an acceptable safety profile, exhibited linear PK characteristics, and no detected antibodies to CNTO 5825.

Golimumab pharmacokinetics after repeated subcutaneous and intravenous administrations in patients with rheumatoid arthritis and the effect of concomitant methotrexate: an open-label, randomized study.

BACKGROUND: The pharmacokinetics of golimumab, a human monoclonal antibody that inhibits the activity of tumor necrosis factor α, after a single subcutaneous (SC) or intravenous (IV) administration have been previously studied. OBJECTIVES: The purpose of this study was to assess the pharmacokinetics of golimumab after multiple SC or IV administrations in patients with active rheumatoid arthritis (RA). The effect of concomitant methotrexate (MTX) use on golimumab pharmacokinetics was evaluated. METHODS: In this open-label, randomized, Phase I study, 49 adult patients with RA received SC golimumab 100 mg (n = 33) every 4 weeks through week 20 or IV golimumab 2 mg/kg (n = 16) at weeks 0 and 12. Serial blood samples were collected, and serum golimumab concentration was measured with an electrochemiluminescent immunoassay. Golimumab pharmacokinetic parameters were derived with the use of a noncompartmental analysis. Adverse events were monitored at every visit. RESULTS: The population was predominantly Caucasian (84%) and female (76%), and the median age was 57 years. After SC golimumab administration, the serum golimumab concentration achieved steady state by ∼12 weeks with mean trough serum concentrations ranging from 1.15 to 1.24 µg/mL. After the final 30-minute IV infusion of golimumab 2 mg/kg, the mean (SD) clearance (CL) was 7.5 (2.6) mL/d/kg. The mean terminal half-life after SC and IV administrations was ∼13 days. The mean absolute bioavailability for SC golimumab was estimated to be 53%. The geometric mean of golimumab CL/F in patients with and without concomitant MTX use was 13.9 and 21.2 mL/d/kg, respectively, and the geometric mean ratio of CL/F was 65.5% (90% CI: 45.2%-94.9%, P = 0.06). Golimumab was generally well tolerated. No malignancies or deaths occurred during the study. CONCLUSIONS: Pharmacokinetics of golimumab were consistent after SC or IV administration in this population of patients with RA. Golimumab was well tolerated and no unexpected adverse events were observed in this trial.

Molecular profiling and gene expression analysis in cutaneous sarcoidosis: the role of interleukin-12, interleukin-23, and the T-helper 17 pathway.

BACKGROUND: Cutaneous sarcoidosis (CS) skin provides relatively noninvasive access to granulomatous sarcoidosis tissue. OBJECTIVE: We sought to explore the role of the T-helper (Th)1 and Th17 pathways in sarcoidosis. METHODS: We used molecular profiling and gene expression analysis to analyze the Th1 and Th17 pathways and other immune-mediated pathways in CS. Molecular profiles were obtained from sarcoidosis skin lesions (lesional skin [LS]), unaffected skin from patients with CS (non-LS), and the skin of healthy control subjects. Whole blood was collected to compare the molecular profile of sarcoidosis skin lesions and whole blood. RESULTS: Twenty participants were enrolled: 15 with active CS and 5 healthy volunteers. Microarray analyses comparing non-LS and healthy volunteer skin with LS showed several thousand genes differentially expressed (≥2-fold change false discovery rate, P < .01). Targeted selections of genes associated with Th1 and Th17 phenotypes showed a strong Th1 profile of sarcoidosis and expression of interleukin (IL)-23 and IL-23R with limited expression of other Th17 pathway genes. IL-21 and signal transducer and activator of transcription 3 (STAT3) were also dysregulated in skin and whole blood, providing additional evidence for involvement of the IL-12 pathway and potential activation of the Th17 pathway. LIMITATIONS: Measurements were made at a single point in time and may not identify mechanisms that may be identified in patients followed up longitudinally. CONCLUSION: These findings provide novel insight into the dysregulated pathways that may be involved in the pathogenesis of sarcoidosis.

Double-blind crossover study to assess potential differences in cytochrome P450 3A4 activity in healthy subjects receiving ondansetron plus dexamethasone, with and without aprepitant.

PURPOSE: Because glucocorticoids and the neurokinin-1 receptor antagonist aprepitant influence CYP3A4 activity, this study assessed whether aprepitant added to a 5-HT(3) antagonist and glucocorticoid would affect CYP3A4 induction. METHODS: In this double-blind, 2-period crossover study, 12 subjects were randomized to receive a triple regimen (oral aprepitant [A] 125 mg, intravenous ondansetron [O] 32 mg, and oral dexamethasone [D] 12 mg day 1; A 80 mg and D 8 mg days 2-3; D 8 mg day 4) in 1 of 2 periods, and a dual regimen (O 32 mg and D 20 mg day 1; D 8 mg bid days 2-4); the D dose was adjusted to account for known dexamethasone/aprepitant interaction. Oral (2 mg) and intravenous (1 mg) stable isotope ((13)C(5) (15)N(1))-labeled midazolam were simultaneously given as probes on days -1, 6, 8, 15, and 22 of each period. If the a priori 90% confidence interval for the day 6 geometric mean oral midazolam AUC(0-∞) ratio (triple/dual regimen) of fold-change from baseline was above 0.5, it would be concluded that there was no clinically meaningful between-regimen difference in CYP3A4 activity. RESULTS: Day 6 oral midazolam AUC(0-∞) geometric mean fold-change from baseline was 0.84 (0.30-1.58 with A, 0.46-1.69 without A). The ratio of geometric mean oral midazolam AUC(0-∞) fold-changes was 1.00 (90% confidence interval 0.80, 1.25). CONCLUSIONS: Aprepitant plus a 5-HT(3) antagonist and dexamethasone is unlikely to have a significant additional inductive effect on CYP3A4 activity beyond that of the dual regimen.

In vitro and in vivo properties of 3-tert-butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4-triazol-5-ylmethoxy)-pyrazolo[1,5-d]-[1,2,4]triazine (MRK-016), a GABAA receptor alpha5 subtype-selective inverse agonist.

3-tert-Butyl-7-(5-methylisoxazol-3-yl)-2-(1-methyl-1H-1,2,4-triazol-5-ylmethoxy)-pyrazolo[1,5-d][1,2,4]triazine (MRK-016) is a pyrazolotriazine with an affinity of between 0.8 and 1.5 nM for the benzodiazepine binding site of native rat brain and recombinant human alpha1-, alpha2-, alpha3-, and alpha5-containing GABA(A) receptors. It has inverse agonist efficacy selective for the alpha5 subtype, and this alpha5 inverse agonism is greater than that of the prototypic alpha5-selective compound 3-(5-methylisoxazol-3-yl)-6-[(1-methyl-1,2,3-triazol-4-hdyl)methyloxy]-1,2,4-triazolo[3,4-a]phthalazine (alpha5IA). Consistent with its greater alpha5 inverse agonism, MRK-016 increased long-term potentiation in mouse hippocampal slices to a greater extent than alpha5IA. MRK-016 gave good receptor occupancy after oral dosing in rats, with the dose required to produce 50% occupancy being 0.39 mg/kg and a corresponding rat plasma EC(50) value of 15 ng/ml that was similar to the rhesus monkey plasma EC(50) value of 21 ng/ml obtained using [(11)C]flumazenil positron emission tomography. In normal rats, MRK-016 enhanced cognitive performance in the delayed matching-to-position version of the Morris water maze but was not anxiogenic, and in mice it was not proconvulsant and did not produce kindling. MRK-016 had a short half-life in rat, dog, and rhesus monkey (0.3-0.5 h) but had a much lower rate of turnover in human compared with rat, dog, or rhesus monkey hepatocytes. Accordingly, in human, MRK-016 had a longer half-life than in preclinical species ( approximately 3.5 h). Although it was well tolerated in young males, with a maximal tolerated single dose of 5 mg corresponding to an estimated occupancy in the region of 75%, MRK-016 was poorly tolerated in elderly subjects, even at a dose of 0.5 mg, which, along with its variable human pharmacokinetics, precluded its further development.

Effect of aprepitant on the pharmacokinetics of intravenous midazolam.

Oral aprepitant 125 mg, an antiemetic and a moderate inhibitor of the metabolism of oral midazolam, was assessed for interaction with intravenous midazolam in 12 subjects randomized to intravenous midazolam 2 mg +/- oral aprepitant 125 mg. The hypothesis was that midazolam AUC would not change by more than 2-fold (consistent with no more than weak inhibition) when midazolam + aprepitant was compared with midazolam alone. An AUC geometric mean ratio (midazolam + aprepitant/midazolam) with 90% confidence interval upper bound < or =2.0 (an increase in midazolam felt to be of modest clinical significance in the highly monitored perioperative period) was prespecified. Aprepitant increased intravenous midazolam AUC(0-infinity) 1.47-fold (90% confidence interval, 1.36-1.59), which fell within the prespecified criterion.

Lack of effect of aprepitant on hydrodolasetron pharmacokinetics in CYP2D6 extensive and poor metabolizers.

To prevent chemotherapy-induced nausea and vomiting, aprepitant is given with a corticosteroid and a 5-hydroxytryptamine type 3 antagonist, such as dolasetron. Dolasetron is converted to the active metabolite hydrodolasetron, which is cleared largely via CYP2D6. The authors determined whether aprepitant, a moderate CYP3A4 inhibitor, alters hydrodolasetron pharmacokinetics in CYP2D6 poor and extensive metabolizers. Six CYP2D6 poor and 6 extensive metabolizers were randomized in an open-label, crossover fashion to treatment A (dolasetron 100 mg on day 1) and treatment B (dolasetron 100 mg plus aprepitant 125 mg on day 1, aprepitant 80 mg on days 2-3). For hydrodolasetron area under the concentration-versus-time curve (AUC0-infinity) and peak plasma concentration (Cmax), geometric mean ratios (B/A) and 90% confidence intervals (CIs) fell below the predefined limit (2.0) for clinical significance (AUC0-infinity, 1.09 [90% CI, 1.01-1.18], Cmax, 1.08 [90% CI, 0.94-1.24]). Aprepitant did not affect the pharmacokinetics of hydrodolasetron, regardless of CYP2D6 metabolizer type, and was generally well tolerated when coadministered with dolasetron in volunteers.

Pharmacokinetics of aprepitant after single and multiple oral doses in healthy volunteers.

Aprepitant is the first NK1 receptor antagonist approved for use with corticosteroids and 5HT3 receptor antagonists to prevent chemotherapy-induced nausea and vomiting (CINV). The effective dose to prevent CINV is a 125-mg capsule on day 1 followed by an 80-mg capsule on days 2 and 3. Study 1 evaluated the bioavailability of the capsules and estimated the effect of food. The mean (95% confidence interval [CI]) bioavailabilities of 125-mg and 80-mg final market composition (FMC) capsules, as assessed by simultaneous administration of stable isotope-labeled intravenous (i.v.) aprepitant (2 mg) and FMC capsules, were 0.59 (0.53, 0.65) and 0.67 (0.62, 0.73), respectively. The geometric mean (90% CI) area under the plasma concentration time curve (AUC) ratios (fed/fasted) were 1.2 (1.10, 1.30) and 1.09 (1.00, 1.18) for the 125-mg and 80-mg capsule, respectively, demonstrating that aprepitant can be administered independently of food. Study 2 defined the pharmacokinetics of aprepitant administered following the 3-day regimen recommended to prevent CINV (125 mg/80 mg/80 mg). Consistent daily plasma exposures of aprepitant were obtained following this regimen, which was generally well tolerated.

Effect of impaired renal function and haemodialysis on the pharmacokinetics of aprepitant.

BACKGROUND: The neurokinin NK(1)-receptor antagonist aprepitant has demonstrated efficacy in preventing highly emetogenic chemotherapy-induced nausea and vomiting. OBJECTIVE: The objective of the present study was to investigate the effects of impaired renal function on the pharmacokinetics and safety of aprepitant. SUBJECTS AND METHODS: A total of 32 patients and healthy subjects were evaluated in this open-label, two-part study. Pharmacokinetic parameters after a single oral dose of aprepitant 240 mg were measured in eight patients with end-stage renal disease (ESRD) requiring haemodialysis, eight patients with severe renal insufficiency (SRI [24-hour creatinine clearance <30 mL/min/1.73 m(2)]) and 16 healthy and age-, sex- and weight-matched subjects (controls). RESULTS: In ESRD patients, the area under the plasma concentration-time curve (AUC) from 0 to 48 hours (AUC(48)) for aprepitant was on average approximately 36% lower than that observed in control subjects (ratio [ESRD patients/healthy controls] of geometric means = 0.64), but the 90% confidence interval 0.52, 0.78 for the ratio of true mean AUC(48) fell within the predefined target interval of 0.5, 2.0. Also in ESRD patients, there was no statistically or clinically significant difference in unbound aprepitant AUC (which may be more clinically relevant than total aprepitant AUC) when compared with healthy control subjects. Aprepitant pharmacokinetic parameters in ESRD patients were clinically similar when haemodialysis was initiated at 4 hours or 48 hours after aprepitant administration. In SRI patients, the ratio (SRI patients/healthy controls) of aprepitant AUC from zero to infinity (AUC(infinity)) geometric mean value was 0.79 with a 90% confidence interval of 0.56, 1.10. On average, in SRI patients the principal aprepitant pharmacokinetic parameters (AUC(infinity), initial maximum plasma concentration [C(max)], time to initial C(max), and apparent elimination half-life) were not statistically different from those obtained in healthy control subjects. Aprepitant was generally well tolerated in both ESRD and SRI patients. CONCLUSION: The results of this study demonstrate that ESRD, haemodialysis and SRI have no clinically meaningful effect on aprepitant pharmacokinetics. Therefore, no dosage adjustment of aprepitant is warranted in SRI or ESRD patients.

Lack of effect of aprepitant on the pharmacokinetics of docetaxel in cancer patients.

BACKGROUND: Aprepitant is a selective neurokinin-1 receptor antagonist that is effective for the prevention of nausea and vomiting caused by highly emetogenic chemotherapy. In vitro, aprepitant is a moderate inhibitor of the CYP3A4 enzyme, which is involved in the clearance of several chemotherapeutic agents. In this study we examined the potential for aprepitant to affect the pharmacokinetics and toxicity of intravenously administered docetaxel, a chemotherapeutic agent that is primarily metabolized by CYP3A4. METHODS: A total of 11 cancer patients (4 male, 7 female, aged 50-68 years) were enrolled in this multicenter, randomized, open-label, two-period, crossover study. Patients received a single infusion of docetaxel monotherapy, 60-100 mg/m(2), on two occasions at least 3 weeks apart. During one of the cycles (treatment A), patients received docetaxel alone. During the alternate cycle (treatment B), they also received aprepitant 125 mg orally 1 h prior to docetaxel infusion (day 1), and a single oral dose of aprepitant 80 mg on days 2 and 3. The pharmacokinetic profile of docetaxel was assessed over 30 h following docetaxel infusion. Blood counts were monitored on days 1, 4, 7, and 14. RESULTS: Ten patients completed the study. Concomitant administration of aprepitant did not cause any statistically or clinically significant changes in docetaxel pharmacokinetics. Values for docetaxel alone (treatment A) versus docetaxel with aprepitant (treatment B) were as follows: geometric mean AUC(0-last) was 3.26 vs 3.17 microg h/ml (P>0.25; ratio B/A 0.97); geometric mean AUC(0-infinity) 3.51 vs 3.39 microg h/ml (P>0.25; ratio B/A 0.96); geometric mean C(max) was 3.53 vs 3.37 microg/ml (P>0.25; ratio B/A 0.95); and geometric mean plasma clearance was 23.3 vs 24.2 l/h/m(2) (P>0.25; ratio B/A 1.04). The corresponding harmonic mean half-life values were 10.1 and 8.5 h. The two treatment regimens had similar tolerability profiles; the median absolute neutrophil count nadirs were 681/mm(3) during treatment with docetaxel alone and 975/mm(3) during aprepitant coadministration. CONCLUSIONS: Aprepitant had no clinically significant effect on either the pharmacokinetics or toxicity of standard doses of docetaxel in cancer patients. Aprepitant at clinically recommended doses may have a low potential to affect the pharmacokinetics of intravenous chemotherapeutic agents metabolized by CYP3A4.

Aprepitant: an oral NK1 antagonist for the prevention of nausea and vomiting induced by highly emetogenic chemotherapy.

This paper reviews the clinical profile of aprepitant, the first neurokinin-1 (NK(1)) receptor antagonist to be approved for use in the prevention of chemotherapy-induced nausea and vomiting. When given to patients receiving highly emetogenic chemotherapy, aprepitant in combination with a 5-hydroxytryptamine type-3 (5HT(3)) receptor antagonist and a corticosteroid provides significantly improved protection from chemotherapy-induced nausea and vomiting over that which has been previously achievable with current antiemetics.

Human positron emission tomography studies of brain neurokinin 1 receptor occupancy by aprepitant.

BACKGROUND: Aprepitant is a highly selective substance P (neurokinin 1 [NK(1)] receptor) antagonist that significantly improves the pharmacotherapy of acute and delayed highly emetogenic chemotherapy-induced nausea and vomiting, probably through an action in the brain stem region of the central nervous system. Here, we report the use of positron emission tomography imaging with the NK(1) receptor binding-selective tracer [(18)F]SPA-RQC to determine the levels of central NK(1) receptor occupancy achieved by therapeutically relevant doses of aprepitant in healthy humans. METHODS: Two single-blind, randomized, placebo-controlled studies in healthy subjects were performed. The first study evaluated the plasma concentration-occupancy relationships for aprepitant dosed orally at 10, 30, 100, or 300 mg, or placebo (n = 12). The second study similarly evaluated oral aprepitant 30 mg and placebo (n = 4). In each study, dosing was once daily for 14 consecutive days. Data from both studies were combined for analyses. The ratio of striatal/cerebellar [(18)F]SPA-RQ (high receptor density region/reference region lacking receptors) was used to calculate trough receptor occupancy 24 hours after the last dose of aprepitant. RESULTS: Brain NK(1) receptor occupancy increased after oral aprepitant dosing in both a plasma concentration-related (r =.97; 95% confidence interval [CI] =.94-1.00, p <.001) and a dose-related (r =.94; 95% CI =.86-1.00, p <.001) fashion. High (> or =90%) receptor occupancy was achieved at doses of 100 mg/day or greater. The plasma concentrations of aprepitant that achieved 50% and 90% occupancy were estimated as approximately 10 ng/mL and approximately 100 ng/mL, respectively. CONCLUSIONS: Positron emission tomography imaging with [(18)F]SPA-RQ allows brain NK(1) receptor occupancy by aprepitant to be predicted from plasma drug concentrations and can be used to guide dose selection for clinical trials of NK(1) receptor antagonists in central therapeutic indications.

Evaluation of potential inductive effects of aprepitant on cytochrome P450 3A4 and 2C9 activity.

The NK(1) receptor antagonist aprepitant (EMEND(R)), developed for use in combination with a 5HT(3) receptor antagonist and a corticosteroid to prevent highly emetogenic chemotherapy-induced nausea and vomiting (CINV), has been shown to have a moderate inhibitory effect as well as a possible inductive effect on cytochrome P450 (CYP) 3A4. Aprepitant has been noted to produce modest decreases in plasma S(-)-warfarin concentrations, suggesting potential induction of CYP2C9. Because metabolism of some chemotherapeutic agents may involve CYP3A4, the potential inductive effect of the CINV dosing regimen of aprepitant on this metabolic pathway was evaluated using intravenous midazolam, a sensitive probe substrate of CYP3A4. The time course of induction of CYP2C9 by aprepitant was also evaluated using oral tolbutamide, a probe substrate of CYP2C9. In this double-blind, randomized, placebo-controlled, single-center study, 24 healthy subjects were randomized (12 subjects per group) to receive either an aprepitant 3-day regimen (aprepitant 125 mg p.o. on day 1 and aprepitant 80 mg p.o. on days 2 and 3) or matching placebo. All subjects also received probe drugs (midazolam 2 mg i.v. and tolbutamide 500 mg p.o.) once prior to aprepitant dosing (baseline) and again on days 4, 8, and 15. The ratio (aprepitant/placebo) of the geometric mean area under the plasma concentration curve (AUC) fold-change from baseline for midazolam was 1.25 on day 4 (p < 0.01), 0.81 on day 8 (p < 0.01), and 0.96 on day 15 (p = 0.646). The ratio (aprepitant/placebo) of the geometric mean AUC fold-change from baseline for tolbutamide was 0.77 on day 4 (p < 0.01), 0.72 on day 8 (p < 0.001), and 0.85 on day 15 (p = 0.05). Assessed using intravenous midazolam as a probe, aprepitant 125/80 mg p.o. administered over days 1 to 3 produced clinically insignificant weak inhibition (day 4) and induction (day 8) of CYP3A4 activity and no effect on CYP3A4 activity on day 15. Assessed using oral tolbutamide as a probe, the aprepitant regimen also produced modest induction of CYP2C9 activity on days 4 and 8, which resolved nearly to baseline by day 15. Thus, the aprepitant regimen for CINV results in modest, transient induction of CYPs 3A4 and 2C9 in the 2 weeks following administration.

Pharmacokinetics of etoricoxib in patients with renal impairment.

The effect of renal insufficiency on the pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase-2, was examined in 23 patients with varying degrees of renal impairment (12 moderate [creatinine clearance between 30 and 50 mL/min/1.73 m2], 5 severe [creatinine clearance below 30 mL/min/1.73 m2], and 6 with end-stage renal disease requiring hemodialysis) following administration of single 120-mg oral doses of etoricoxib. Even the most severe renal impairment was found to have little effect on etoricoxib pharmacokinetics. The low recovery of etoricoxib in dialysate (less than 6% of the dose) supports that hemodialysis also has little effect on etoricoxib pharmacokinetics, and binding of etoricoxib to plasma proteins was generally unaffected by renal disease. Single doses of etoricoxib were generally well tolerated by patients with renal impairment. Based on pharmacokinetic considerations, dosing adjustments are not necessary for patients with any degree of renal impairment. However, because patients with advanced renal disease (creatinine clearance below 30 mL/min/1.73 m2) are likely to be very sensitive to any further compromise of renal function, and there is no long-term clinical experience in these patients, the use of etoricoxib is not recommended in patients with advanced renal disease.

Pharmacokinetics of etoricoxib in patients with hepatic impairment.

The effect of hepatic insufficiency on the pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase-2, was investigated following administration of single and multiple oral doses to mild hepatic insufficiency patients (Child-Pugh score of 5 to 6), multiple oral doses to moderate hepatic insufficiency patients (Child-Pugh score of 7 to 9), and single intravenous doses to both mild and moderate hepatic insufficiency patients. A trend of decreasing systemic clearance with increasing hepatic impairment was observed. Absorption of etoricoxib was unaffected by hepatic impairment. Binding of etoricoxib to plasma proteins was also found to be unaffected by hepatic disease. Etoricoxib was generally well tolerated by patients with mild and moderate hepatic insufficiency. Together, these results support a 60-mg once-daily dosing regimen for mild hepatic insufficiency patients and a 60-mg every-other-day dosing regimen for moderate hepatic insufficiency patients. There are no clinical or pharmacokinetic data in patients with severe hepatic insufficiency (Child-Pugh score > 9).

Lack of effect of aprepitant on digoxin pharmacokinetics in healthy subjects.

Aprepitant is a highly selective neurokinin-1 receptor antagonist that, in combination with a corticosteroid and a 5-hydroxytryptamine3 (5HT3) receptor antagonist, has been shown to be efficacious in the prevention of highly emetogenic chemotherapy-induced nausea and vomiting. In vitro data suggest that aprepitant is a substrate and a weak inhibitor of P-glycoprotein. Thus, the effect of aprepitant on the pharmacokinetics of digoxin, a P-glycoprotein substrate, was examined in a double-blind, placebo-controlled, randomized, two-period crossover study in 12 healthy subjects. Each subject received daily oral doses of digoxin 0.25 mg on Days 1 through 13 during both treatment periods. Aprepitant 125 mg (or matching placebo) was coadministered orally with digoxin on Day 7, and aprepitant 80 mg (or matching placebo) was coadministered orally with digoxin on Days 8 to 11. Aprepitant did not affect the pharmacokinetics of digoxin. The geometric mean ratios (90% confidence interval [CI]) for plasma AUC0-24 h of digoxin (with/without aprepitant) were 0.99 (0.91, 1.09) and 0.93 (0.83, 1.05) on Days 7 and 11, respectively, and the geometric mean ratios (90% CI) for the 24-hour urinary excretion of immunoreactive digoxin (with/without aprepitant) were 0.91 (0.80, 1.04) and 1.00 (0.91, 1.09) on Days 7 and 11, respectively. Thus, aprepitant, when dosed as a 5-day regimen, did not interact with a known substrate of the P-glycoprotein transporter.