Journal of Clinical Pharmacology最新文献

Ceftaroline, the active form of ceftaroline fosamil, is a broad-spectrum cephalosporin antibiotic. A population pharmacokinetic (PPK) model for ceftaroline was developed in NONMEM® using data from 185 healthy subjects and 92 patients with acute bacterial skin and skin structure infection (ABSSSI). Data from 128 patients with community-acquired bacterial pneumonia (CABP) were used for external model validation. Healthy subjects received 50-2,000 mg ceftaroline fosamil via intravenous (IV) infusion over 1 hour or intramuscular (IM) injection q12h or q24h. ABSSSI and CABP patients received 600 mg of ceftaroline fosamil IV over 1 hour q12h. A three-compartment model with zero-order IV or parallel first-order IM input and first-order elimination described ceftaroline fosamil PK. A two-compartment model with first-order conversion of prodrug to ceftaroline and parallel linear and saturable elimination described ceftaroline PK. Creatinine clearance was the primary determinant of ceftaroline exposure. Good agreement between the observed data and both population (r(2)  = 0.93) and individual post-hoc (r(2)  = 0.98) predictions suggests the PPK model can adequately approximate ceftaroline PK using covariate information. Such a PPK model can evaluate dose adjustments for patients with renal impairment and generate ceftaroline exposures for use in pharmacokinetic-pharmacodynamic assessments of efficacy in patients with ABSSSI or CABP.

To characterize doxylamine pharmacokinetics in children. This study was conducted in 41 subjects, ages 2-17 years. Doxylamine succinate doses based on age/weight ranged from 3.125 to 12.5 mg. A single oral dose was administered with 2 to 4 oz. of water or decaffeinated beverages ∼2 hours after a light breakfast. Plasma samples were obtained before and for 72 hours after dosing and analyzed for doxylamine using HPLC MS/MS. Pharmacokinetic parameters were estimated using non-compartmental methods and relationships with age were assessed using linear regression. Over the fourfold dose range, Cmax was similar while AUC increased only 60%, although not statistically significant (P-value = 0.0517). As expected due to increasing body size, CLo and Vz /F increased with age. Due to a similar increase with age for Clo and Vz /F, no age-related differences in t1/2,z were observed (∼16 hours). Allometric scaling indicated no maturation related changes in CLo ; although Vz /F remained age-dependent, the predicted range decreased ∼70%. Overall, the single doses were well tolerated. Somnolence was the most common reported AE with no apparent differences in incidence noted with age. An age/weight dosing nomogram utilizing a fourfold range of doses achieves similar Cmax , whereas AUC increases only 60%.

Studies of liver transplant (LT) patients, mainly in Asians, have evaluated the influence of the CYP3A5*1 allele and P-glycoprotein gene ABCB1 on tacrolimus pharmacokinetics or biopsy-proven acute rejection (BPAR) incidence, with no conclusive results. To investigate these issues, 98 Caucasian Spanish LT patients with tacrolimus, mycophenolate mofetil and steroids and 88 cadaveric donors were genotyped for the SNPs CYP3A5 6986G>A, ABCB1 1236C>T, ABCB1 2677G>A/T and ABCB1 3435C>T;. On day 7 post-LT, patients with a native CYP3A5*1 allele had significantly lower tacrolimus trough concentrations C0 (P = .03) and dose-adjusted concentrations C0 /D (P = .02) than CYP3A5 *3/*3 homozygotes. Three months post-LT, patients carrying a liver with CYP3A5*1 had significantly lower C0 /D (P = .03) and took significantly higher tacrolimus doses (P = .03) than the corresponding *3/*3 homozygotes. ABCB1 SNPs showed no significant association with tacrolimus variables. The 3-month incidence of BPAR was 10.2%, with no statistically significant differences related to CYP3A5 (14.3% in expresser vs. 9.5% in non-expresser) or ABCB1 genotype of either patient or donor. We conclude that in Caucasian Spanish LT patients, a native or graft-borne CYP3A5*1 allele tends to lower tacrolimus concentrations and increase dosage needs, but has no significant impact on the incidence of BPAR.

Vincristine sulfate liposome injection (VSLI,) is a sphingomyelin and cholesterol nanoparticle formulation of vincristine sulfate (VCR) that was designed to overcome the dosing and pharmacokinetic limitations of standard VCR. In contrast to the rapid CL and wide tissue distribution of non-liposomal VCR, VSLI circulates in plasma for a prolonged period of time, with a slow CL of 345 mL/h and relatively small Vd of 3,570 mL. This facilitates enhanced and prolonged tumor-tissue delivery of VCR. The maximum tolerated dose of VSLI, 2.25 mg/m(2) once per week without a dose cap, enables individual and cumulative VCR exposure unachievable with non-liposomal VCR at its labeled dose of 1.4 mg/m(2) . VSLI is associated with a dose-dependent peripheral neurotoxicity albeit at doses that are two to three times that of standard VCR. VCR dose intensification with VSLI correlated with an increased probability of overall response and a strong trend towards increased complete response in adults with relapsed and/or refractory acute lymphoblastic leukemia. Overall, VSLI improves the therapeutic index by facilitating increased dose intensification while maintaining a predictable and manageable safety profile.

Electronic Medical Records (EMRs) are wealthy storehouses of patient information, to which data mining techniques can be prudently applied to reveal clinically significant patterns. Detecting patterns in drug-drug interactions, leading to adverse drug reactions is a powerful application of EMR data mining. Adverse effects of drug treatments can be investigated by mining clinical laboratory tests data which are reliable indicators of abnormal physiological functions. We report here the co-medication effects of pravastatin (HMG-CoA reductase inhibitor) and paroxetine (selective serotonin reuptake inhibitor (SSRI) anti-depressant) on significant clinical parameters, identified through a data mining analysis conducted on the Allscripts data warehouse. We found that the concomitant drug treatments of pravastatin and paroxetine increased the mean values of glucose serum from 113.2 to 132.1 mg/dL and international normalized ratio (INR) from 2.18 to 2.52, respectively. It also decreased the mean values of estimated glomerular filtration rate (eGFR) from 43 to 37 mL/min/1.73 m(3) and blood CO2 levels from 24.8 to 23.9 mEq/L respectively. Our findings indicate that co-medication of pravastatin and paroxetine might have significant impact on blood anti-coagulation, kidney function, and glucose homeostasis. Our methodology can be applied to any EMR data set to reveal co-medication effects of any drug pairs.

Results of pharmacometric analyses influence high-level decisions such as clinical trial design, drug approval, and labeling. Key challenges for timely delivery of pharmacometric analyses are the data assembly process and tracking and documenting the modeling process and results. Since clinical efficacy and safety data typically reside in the biostatistics computing area, an integrated computing platform for pharmacometric and biostatistical analyses would be ideal. A case study is presented integrating a pharmacometric modeling platform into an existing statistical computing environment (SCE). The feasibility and specific configurations of running common PK/PD programs such as NONMEM and R inside of the SCE are provided. The case study provides an example of an integrated repository that facilitates efficient data assembly for pharmacometrics analyses. The proposed platform encourages a good pharmacometrics working practice to maintain transparency, traceability, and reproducibility of PK/PD models and associated data in supporting drug development and regulatory decisions.

Adverse drug reactions (ADR) are underreported by doctors despite numerous efforts. We aimed to determine if establishing an "ADR reporting doctor's network" within a hospital would increase the quantity of ADRs reported by hospital doctors. One hundred hospital doctors joined the network. Email reminders were sent to network members during the 1 year study period, conveying information about ADRs reported, amusingly and pleasantly reminding them to report ADRs in minimal detail, by phone, email, text message or mail to the Clinical Pharmacology Unit, who would further complete the report. A total of 114 ADRs were reported during the study period in comparison to 48, 26, and 17 in the previous 3 years (2008, 2009, 2010, respectively). In the 3 years prior, doctors reported 41.7% of the reported ADRs whereas in the study period, doctors reported 74.3% of ADRs (P < .001), reflecting an 80% increase in doctors reports. Ninety seven percent of doctors' reports were of ADR network members. Thirty-four (34%) network members reported an ADR during the study period and 31 of the 34 reporters had never reported ADRs before becoming network members. Establishing an ADR network of doctors substantially increases ADR reporting amongst its members.

GSK1322322 is the first in a new class of antibiotics that targets peptide deformylase (PDF), an essential bacterial enzyme required for protein maturation. This randomized, double-blind, placebo-controlled, eight-cohort phase I trial enrolled 62 healthy volunteers to assess safety, tolerability, and pharmacokinetic profiles of GSK1322322. GSK1322322 was administered as a single oral or intravenous (IV) dose, escalating from 500 to 3,000 mg or repeat IV doses escalating from 500 to 1,500 mg twice daily. Upon repeat IV administration, GSK1322322 exhibits linear pharmacokinetics over time upon repeat doses as shown by time-invariant pharmacokinetics. A dose-proportional increase in area under concentration-time curve was observed after single or repeat IV dosing, whereas clearance at steady state remained generally unchanged across doses. There was minimal accumulation of GSK1322322 after repeat IV twice-daily administration. After oral tablet doses of GSK1322322 1,000 and 1,500 mg, absolute bioavailability was 69% and 56%, respectively. GSK1322322 administration at single and repeat IV doses and at supratherapeutic single IV doses of 2,000 and 3,000 mg was associated with mild-to-moderate drug-related adverse events. On the basis of the pharmacokinetics and tolerability demonstrated in this study, GSK1322322 has the potential to become the first-in-class PDF inhibitor for clinical use.

Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers monomethyl auristatin E (MMAE) into CD30-expressing cells. This study evaluated the CYP3A-mediated drug-drug interaction potential of brentuximab vedotin and the excretion of MMAE. Two 21-day cycles of brentuximab vedotin (1.2 or 1.8 mg/kg intravenously) were administered to 56 patients with CD30-positive hematologic malignancies. Each patient also received either a sensitive CYP3A substrate (midazolam), an effective inducer (rifampin), or a strong inhibitor (ketoconazole). Brentuximab vedotin did not affect midazolam exposures. ADC exposures were unaffected by concomitant rifampin or ketoconazole; however, MMAE exposures were lower with rifampin and higher with ketoconazole. The short-term safety profile of brentuximab vedotin in this study was generally consistent with historic clinical observations. The most common adverse events were nausea, fatigue, diarrhea, headache, pyrexia, and neutropenia. Over a 1-week period, ∼23.5% of intact MMAE was recovered after administration of brentuximab vedotin; all other species were below the limit of quantitation. The primary excretion route is via feces (median 72% of the recovered MMAE). These results suggest that brentuximab vedotin (1.8 mg/kg) and MMAE are neither inhibitors nor inducers of CYP3A; however, MMAE is a substrate of CYP3A.

This study evaluated the plasma concentrations of oxycodone and its demethylates and opioid-induced adverse effects based on cachexia stage in cancer patients receiving oxycodone. Seventy patients receiving oxycodone for cancer pain were enrolled. Cachexia was evaluated using the Glasgow Prognostic Score (GPS). Predose plasma concentrations of oxycodone, oxymorphone, and noroxycodone were determined at the titration dose. Opioid-induced adverse effects were monitored for 2 weeks after the titration. Plasma concentrations of oxycodone and oxymorphone but not noroxycodone in patients with a GPS of 2 were significantly higher than that with a GPS of 0. The metabolic ratios of noroxycodone but not oxymorphone to oxycodone in patients with a GPS of 1 and 2 were significantly lower than in those with a GPS of 0. A higher GPS was associated with a higher incidence of somnolence, while the GPS did not affect the incidence of vomiting. Plasma concentrations of oxycodone and oxymorphone were not associated with the incidence of adverse effects. In conclusion, cancer cachexia raised the plasma exposures of oxycodone and oxymorphone through the reduction of CYP3A but not CYP2D6. Although the cachexia elevated the incidence of somnolence, alterations in their pharmacokinetics were not associated with the incidence.