A randomized study to compare sequential chemoradiotherapy with concurrent chemoradiotherapy for unresectable locally advanced esophageal cancer.

BACKGROUND: Chemotherapy combined with radiotherapy can improve outcome in locally advanced esophageal cancer. AIM: This study aimed to compare efficacy and toxicity between concurrent chemoradiotherapy (CCRT) and sequential chemoradiotherapy (SCRT) in unresectable, locally advanced, esophageal squamous cell carcinoma (ESSC). MATERIALS AND METHODS: Forty-one patients with unresectable, locally advanced ESCC were randomized into two arms. In the CCRT arm (Arm A), 17 patients received 50.4 Gy at 1.8 Gy per fraction over 5.6 weeks along with concurrent cisplatin (75 mg m(-2) intravenously on day 1 and 5-fluorouracil (1000 mg m(-2) continuous intravenous infusion on days 1-4 starting on the first day of irradiation and given after 28 days. In the SCRT arm (Arm B), 20 patients received two cycles of chemotherapy, using the same schedule, followed by radiotherapy fractionated in a similar manner. The endpoints were tumor response, acute and late toxicities, and disease-free survival. RESULTS: With a median follow up of 12.5 months, the complete response rate was 82.4% in Arm A and 35% in Arm B (P = 0.003). Statistically significant differences in frequencies of acute skin toxicity (P = 0.016), gastrointestinal toxicity (P = 0.005) and late radiation pneumonitis (P = 0.002) were found, with greater in the CCRT arm. A modest but non-significant difference was observed in median time to recurrence among complete responders in the two arms (Arm A 13 months and Arm B 15.5 months, P = 0.167) and there was also no significant difference between the Kaplan Meier survival plots (P = 0.641) of disease-free survival. CONCLUSIONS: Compared to sequential chemoradiotherapy, concurrent chemoradiotherapy can significantly improve local control rate but with greater risk of adverse reactions.

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.

Primary Lymphoepithelioma-like Carcinoma of the Lung in a 13 year old Girl.

Lymphoepithelioma-like carcinoma, a large cell carcinoma with pronounced lymphocyte infiltration, is a rare entity mostly seen in the nasopharynx. But primary pulmonary LELC in children & adolescents is extremely rare. Here we present a 13 year old girl with chief complaint of fever, cough, shortness of breath and heaviness in the left side of chest. She underwent left upper lobectomy. Histopathological examination of the biopsy specimen confirmed it to be a case of large cell carcinoma of lung, lymphoepithelioma type, invading pleura (stage pT3N0M0) with high serum titre of anti Epstein-Barr virus IgG antibody.

Adverse drug reaction profile of nanoparticle versus conventional formulation of paclitaxel: An observational study.

OBJECTIVES: Conventional polyethoxylated castor oil (PCO)-based paclitaxel is associated with major adverse drug reactions (ADRs). Nanoxel, a nanoparticle-based formulation, may improve its tolerability by removing the need for PCO vehicle, and also permit its use in a higher dose. We conducted intensive monitoring of the ADR profile of Nanoxel in comparison with conventional paclitaxel in a public tertiary care set-up. MATERIALS AND METHODS: ADR data were collected from 10 patients receiving Nanoxel and 10 age-matched controls receiving conventional paclitaxel in this longitudinal observational study, conducted in a medical oncology ward over 18 months. Severity was graded as per US National Cancer Institute Common Terminology Criteria for Adverse Events. RESULTS: The groups had comparable demography at baseline. The median disease duration and per cycle median dose of paclitaxel were greater in the Nanoxel arm. Total 119 ADRs were noted with Nanoxel and 123 with conventional paclitaxel. Of these, 25 (21.0%, 95% CI 13.69-28.33%) in the Nanoxel and 20 (16.2%, 95% CI 9.74-22.78%) in paclitaxel group were of grade 3/4 severity. Common events included myalgia, nausea, anemia, paresthesia, alopecia, diarrhea, and vomiting with Nanoxel, and paresthesia, anemia, myalgia, anorexia, alopecia, vomiting, diarrhea, stomatitis, and nausea with paclitaxel. Of the less common events (<5%), grade 2 or 3 arthralgia was seen exclusively with Nanoxel while motor neuropathy with muscular weakness was more frequent and severe with conventional paclitaxel. Hypersensitivity reactions were not encountered in either arm, although no antiallergy premedication was employed for Nanoxel. CONCLUSIONS: Despite its ADR profile being statistically comparable to conventional paclitaxel, this observational study suggests that Nanoxel tolerability could be better, considering that a significantly higher dose was employed. This hypothesis needs confirmation through an interventional study.

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.

Comparison of vinorelbine with cisplatin in concomitant chemoradiotherapy in head and neck carcinoma.

AIM: Head and neck cancer is one of the most commonly occurring malignancies in the world. In India, the most commonly occurring head and neck cancers are those of the oral cavity and the pharynx. The majority of these cancers present with stage III/IV disease. Surgery and radiation therapy are the main treatment modalities. Concomitant chemoradiation is being investigated with the goal of improved local control that translates into improved survival. In this background, we have started this prospective randomized trial to ascertain the dose, schedule and sequence of therapy and to note whether Vinorelbine as radiosensitizer is equally effective as Cisplatin, comparing compliance, local control and toxicity. PATIENTS AND METHODS: Forty patients of advanced head and neck cancer were randomized into two arms. Arm A received weekly injection Cisplatin 40mg/m(2) along with radiation. Arm B received weekly injection of Vinorelbine 6mg/m(2) along with radiation. Radiotherapy was delivered at a dose of 6,600-7,000 Gy in conventional fractionation in a telecobalt machine. RESULTS: The complete response (CR) rate was higher in arm B (90%) than in arm A (70%). Major toxicities included neutropenia, anemia, mucositis and nausea. CONCLUSION: Concomitant chemoradiation with Vinorelbine produced more CR than chemoradiation with Cisplatin in advanced head and neck cancer. Toxicities were more in the Cisplatin arm, but they were manageable. Although a majority of the study was performed using Cisplatin as the radiosensitizer, Vinorelbine can be recommended as radiosensitizer in advanced head and neck malignancy.

Pharmacokinetics and tolerability of single-dose intravenous ertapenem in infants, children, and adolescents.

BACKGROUND: Ertapenem is a carbapenem antibiotic with broad spectrum activity and a pharmacokinetic profile that favors once-daily administration in adults. OBJECTIVES: This investigation was designed to evaluate the dose-exposure profile of ertapenem in children from infancy through adolescence. METHODS: Eighty-four children (3 months-16 years) requiring antibiotic therapy were enrolled in this multicenter trial. Children received a single intravenous dose of ertapenem at 15, 20, or 40 mg/kg followed by repeated blood sampling for 24 hours. Free and total plasma ertapenem concentrations were quantitated by high-performance liquid chromatography, and the pharmacokinetics were determined using a model-independent approach. RESULTS: Ertapenem exposure increased proportionally with increasing dose; however, achievable concentrations were influenced by age. Children older than 12 years attained higher dose-normalized concentrations at the end of the infusion (concentration at the end of the infusion [Ceoi]: 8.7 ± 1.9 mg/L per mg/kg dose) and total body exposure (area under the curve area under the plasma concentration-time curve [AUC]0-∞: 34.7 ± 14.7 mg hr/L per mg/kg dose) as compared with children 2 to 12 years (Ceoi: 6.9 ± 2.4 mg/L per mg/kg dose, AUC0-∞: 18.4 ± 8.0 mg hr/L per mg/kg dose) and children younger than 2 years (Ceoi: 6.1 ± 2.2 mg/L per mg/kg dose, AUC0-∞: 17.0 ± 5.4 mg hr/L per mg/kg dose). These findings were accounted for by age-dependent changes in ertapenem clearance and distribution volume. In 3 children adverse events (nausea, n = 2; injection site reaction, n = 1) were considered related to study drug administration. CONCLUSIONS: Children younger than 12 years require dosing more frequently than once daily to achieve optimal efficacy when treating organisms with a minimum inhibitory concentration near the susceptibility breakpoint.

Multiple-dose pharmacokinetics, pharmacodynamics, and safety of taranabant, a novel selective cannabinoid-1 receptor inverse agonist, in healthy male volunteers.

Taranabant is a cannabinoid-1 receptor inverse agonist for the treatment of obesity. This study evaluated the safety, pharmacokinetics, and pharmacodynamics of taranabant (5, 7.5, 10, or 25 mg once daily for 14 days) in 60 healthy male subjects. Taranabant was rapidly absorbed, with a median t(max) of 1.0 to 2.0 hours and a t(1/2) of approximately 74 to 104 hours. Moderate accumulation was observed in C(max) (1.18- to 1.40-fold) and AUC(0-24 h) (1.5- to 1.8-fold) over 14 days for the 5-, 7.5-, and 10-mg doses, with an accumulation half-life ranging from 15 to 21 hours. Steady state was reached after 13 days. After multiple-dose administration, plasma AUC(0-24 h) and C(max) of taranabant increased dose proportionally (5-10 mg) and increased somewhat less than dose proportionally for 25 mg. Taranabant was generally well tolerated up to doses of 10 mg and exhibited multiple-dose pharmacokinetics consistent with once-daily dosing.

Safety, tolerability, pharmacokinetics, and pharmacodynamic properties of taranabant, a novel selective cannabinoid-1 receptor inverse agonist, for the treatment of obesity: results from a double-blind, placebo-controlled, single oral dose study in healthy volunteers.

Taranabant is a novel cannabinoid CB-1 receptor (CB1R) inverse agonist in clinical development for the treatment of obesity. This double-blind, randomized, placebo-controlled, single oral dose study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of taranabant (0.5-600 mg) in 24 healthy male volunteers. Single-dose AUC(0-infinity) and C(max) values for taranabant increased approximately linearly with dose up to 200 mg, with slightly less than dose-proportional increases in AUC(0-infinity) and C(max) values for doses >200 mg. Plasma taranabant had a biphasic disposition, with a median t(max) of 1 to 2.5 hours and a terminal elimination t((1/2)) of 38 to 69 hours. Coadministration of taranabant with a high-fat meal led to a 14% increase in C(max) and a 74% increase in AUC(0-infinity). Clinical adverse experiences associated with single doses of taranabant were generally mild and transient. Of the 198 clinical adverse experiences reported, the most common drug-related ones were nausea (36), headache (22), drowsiness (14), abdominal discomfort/abdominal pain/stomachache (14), hiccups (9), dizziness (8), decreased appetite (7), increased bowel movement (7), mood change (6), tiredness (4), vomiting (4), and sweating increased (4). Taranabant has pharmacokinetic characteristics suitable for a once-daily dosing regimen.

Tolerability of fosaprepitant and bioequivalency to aprepitant in healthy subjects.

Fosaprepitant is an intravenous formulation of aprepitant, an oral NK1 antagonist used to prevent chemotherapy-induced nausea and vomiting. This randomized study was designed to evaluate fosaprepitant in polysorbate 80 vehicle for tolerability and bioequivalency to aprepitant. Tolerability was assessed by physical and laboratory examinations and adverse events. Plasma collected for 72 hours was assayed for aprepitant and fosaprepitant. Analysis of variance models were applied to natural log-transformed aprepitant area under the curve (AUC) data. Fosaprepitant up to 150 mg (1 mg/mL) was generally well tolerated. Fosaprepitant 115 mg was AUC bioequivalent to aprepitant 125 mg; the 90% confidence interval for the geometric mean ratio of aprepitant AUC for fosaprepitant 115 mg/aprepitant 125 mg fell within prespecified equivalence bounds of 0.80 to 1.25.

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.

Pharmacokinetics of ertapenem in patients with varying degrees of renal insufficiency and in patients on hemodialysis.

Ertapenem is a parenteral beta-lactam carbapenem antibiotic. This open-label study examined the pharmacokinetics of single 1-g intravenous doses of ertapenem, administered over 30 minutes, in patients with mild, moderate, and advanced renal insufficiency (RI) and in patients with end-stage renal disease (ESRD) requiring hemodialysis. Pharmacokinetics were compared with historical controls pooled across healthy young and elderly subjects. Area under the concentration-time curve from time zero to infinity increased 7% in mild, 53% in moderate, 158% in advanced RI, and 192% in ESRD; end of infusion concentration changed minimally; half-life was 4.5 hours in the historical control group and 4.4, 6.1, 10.6, and 14.1 hours in mild RI, moderate RI, advanced RI, and ESRD, respectively. Hemodialysis cleared approximately 30% of the dose. The recommended dose in mild to moderate RI and after hemodialysis is unchanged at 1 g daily; and in advanced RI and ESRD is reduced to 0.5 g daily. If the daily dose is given 6 hours prior to hemodialysis, a supplementary 150-mg dose (30% of the daily dose) is recommended postdialysis.

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.

A prospective and randomized study of radiotherapy, sequential chemotherapy radiotherapy and concomitant chemotherapy-radiotherapy in unresectable non small cell carcinoma of the lung.

PURPOSE: Treatment of advanced Non small cell lung cancer (NSCLC) often produces dismal results. Combination of available treatment modalities has reportedly improved the outcome. A prospectively randomized trial was conducted, comparing combined treatment modalities versus radiotherapy alone, in treatment of unresectable NSCLC. MATERIALS AND METHODS: A total of 103 patients were randomized to three groups. In group 'A', 32 patients received radiotherapy alone (6500 cGy/30 fraction). In group 'B', 35 patients received neoadjuvant chemotherapy (Cisplatin 80 mg/m2 on day 1 and Etoposide 100 mg/m day 1-3 intravenously q3 weeks for 3 cycles), followed by radiotherapy (6000 cGy/30 fractions) and 3 more cycles of Chemotherapy, with the same regimen. In group 'C', 36 patients received radiotherapy (5000 cGy/25 fractions) with concurrent chemotherapy (cisplatin 20 mg/m2 + Etoposide 75 mg/m2 intravenously on day 1-5 and day 22-26), followed by 2 more cycles of chemotherapy, q3 weeks with the same regimen. RESULTS: Initial treatment responses were significantly higher in group 'B' (P < 0.05) and 'C' (P < 0.03), compared to group 'A'. Follow-up observations showed, that addition of chemotherapy brought down distant metastasis's from 62.5% (group 'A') to 48.6% (group 'B') and 44.4% (group 'C'). The median time to tumour progression also improved from 16 months (Group 'A') to 21 months (Group 'B' and 'C'). But 2 year follow up did not show any survival benefit. Acute toxicities were more frequent in group 'B' and 'C', but were manageable. CONCLUSION: Addition of chemotherapy with radiation in unresectable NSCLC improves response rates, time to tumour progression and disease free survival, though the same effect is not translated in overall survival.

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.

Pharmacokinetics and pharmacodynamics of ertapenem: an overview for clinicians.

Ertapenem, a Group 1 carbapenem, is a once-a-day parenteral beta-lactam antibiotic recently licensed in the USA and Europe. Monotherapy with ertapenem dosed as 1 g once a day has been shown to be highly effective in clinical trials for the treatment of complicated infections of skin and skin structures, complicated intra-abdominal infections, community-acquired pneumonia, acute pelvic infections and complicated urinary tract infections. Dosing modifications have not been recommended for adults on the basis of gender, age, weight or liver disease. Presently there are no data regarding the use of ertapenem in children. Dose reductions are indicated for patients with advanced renal insufficiency. Ertapenem is neither a substrate nor an inhibitor of P-glycoprotein or cytochrome P450 enzymes; significant drug interactions between ertapenem and drugs handled by these systems are not expected.

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.