Impact of pharmacometric reviews on new drug approval and labeling decisions--a survey of 31 new drug applications submitted between 2005 and 2006.

Exploratory analyses of data pertaining to pharmacokinetic, pharmacodynamic, and disease progression are often referred to as the pharmacometrics (PM) analyses. The objective of the current report is to assess the role of PM, at the Food and Drug Administration (FDA), in drug approval and labeling decisions. We surveyed the impact of PM analyses on New Drug Applications (NDAs) reviewed over 15 months in 2005-2006. The survey focused on both the approval and labeling decisions through four perspectives: clinical pharmacology primary reviewer, their team leader, the clinical team member, and the PM reviewer. A total of 31 NDAs included a PM review component. Review of NDAs involved independent quantitative evaluation by FDA pharmacometricians. PM analyses were ranked as important in regulatory decision making in over 85% of the 31 NDAs. Case studies are presented to demonstrate the applications of PM analysis.

Evaluation of antibiotic synergy against Acinetobacter baumannii: a comparison with Etest, time-kill, and checkerboard methods.

Acinetobacter baumannii is becoming increasingly resistant to antibiotics, often requiring combination therapy. Numerous methods exist to detect the presence of in vitro synergy with the time-kill and checkerboard tests being widely used. The Epsilometer test (E test) is a new method that is less labor intensive, but has not been evaluated using a wide range of antimicrobials and organisms. We assessed synergy using the time-kill and checkerboard tests and compared the results to the E test method using 10 clinical isolates of A. baumannii. Antimicrobial combinations evaluated consisted of trovafloxacin or tobramycin in combination with cefepime or piperacillin. Synergy was detected with all combinations by either the checkerboard or time-kill method. Synergy was not detected by the Etest method. The agreement between the time-kill test and Etest method was 72% (range 42-97%); for the time-kill and checkerboard tests, agreement was 51% (range 30-67%). The Etest method appears promising although further testing should be performed with additional antimicrobial agents and organisms.

Pharmacokinetics of cefepime in patients with thermal burn injury.

The pharmacokinetics of cefepime following administration of a single 2-g dose were evaluated for 12 adult patients with thermal burn injury and suspected or documented infection. Serial blood and urine samples for cefepime concentration determination were obtained for 24 h following drug administration. Serum and urine cefepime concentrations were determined by high-performance liquid chromatography and serum concentrations were fit to a two-compartment pharmacokinetic model. Mean (standard deviation [SD]) age, actual body weight (ABW), percent total body surface area burned, and days postburn at the time of study were 41 (13) years, 84 (22) kg, 36 (17)%, and 9 (3) days, respectively. Mean (SD) measured creatinine clearance (CL(CR)), total clearance (CL(T)), renal clearance (CL(R)), alpha phase half-life, beta phase half-life, and volume of distribution at steady state (V(SS)) were 135 (31) ml/min, 8.8 (2.4) liters/h, 8.1 (2.0) liters/h, 0.33 (0.14) h, 2.8 (0.6) h, and 0.43 (0.10) liters/kg ABW, respectively. Cefepime CL(T) and CL(R) in burn patients were similar to previously reported values for healthy volunteers when normalized by CL(CR). Stepwise multiple regression was used to associate CL(T) with CL(CR) and days postburn (r(2) = 0.861), CL(R) with CL(CR) and days postburn (r(2) = 0.773), nonrenal clearance with percent third-degree (% 3 degrees ) burn and albumin concentration (r(2) = 0.550), and V(SS) only with % 3 degrees burn (r(2) = 0.624). Simulated steady-state serum concentrations obtained by using the patients' pharmacokinetic parameters exceeded the susceptibility interpretive standard (breakpoint) of cefepime for at least 60% of the dosing interval with dosing regimens of 1 g every 8 h (q8h), 2 g q8h, and 2 g q12h. Despite differences in pharmacokinetic parameters between our patients and healthy volunteers, it appears that these dosing regimens may be adequate in similar burn patients.

A pilot study of the efficacy of constant-infusion ceftazidime in the treatment of endobronchial infections in adults with cystic fibrosis.

STUDY OBJECTIVE: To compare the efficacy of constant-infusion ceftazidime (CTZ) with that of traditional intermittent dosing in a pilot trial. DESIGN: Prospective, crossover trial. SUBJECTS: Five adults with cystic fibrosis requiring intravenous antibiotic therapy for pulmonary exacerbations of the disease. INTERVENTIONS: Patients were initially treated with standard CTZ 2 g 3 times/day for 10 days. At the next hospitalization patients were crossed over and CTZ was administered as a constant infusion at a rate determined to achieve a serum concentration 6.6 times the minimum inhibitory concentration (MIC) of the least susceptible Pseudomonas aeruginosa isolate. MEASUREMENTS AND MAIN RESULTS: The pharmacokinetics of CTZ were determined, as were MICs for all P. aeruginosa isolates. Outcome parameters of interest were changes with therapy in white blood cell count, P aeruginosa density in sputum, and pulmonary function test results. Differences in these parameters for the two forms of administration were not significant. With the exception of one patient who received 6 g/day with both regimens, the average reduction in dosage with the constant infusion was 50%. CONCLUSION: These preliminary data suggest that constant-infusion CTZ may be as safe and efficacious as intermittent dosing.

The effect of mesalamine and nicotine in the treatment of inflammatory bowel disease.

OBJECTIVE: To characterize the usefulness of mesalamine and nicotine in the treatment of active ulcerative colitis and inactive Crohn's disease. DATA SOURCES: Citations were selected from the MEDLINE database. Only those involving human subjects, inflammatory bowel disease, and available in English were selected. STUDY SELECTION: Selection criteria of clinical trials and review articles assessing the effects of mesalamine and nicotine in active ulcerative colitis or inactive Crohn's disease and the utility of reducing steroid dependence or relapse rate. Less than 20% of the articles identified met the selection criteria. DATA SYNTHESIS: In patients with inactive Crohn's disease, mesalamine 2 g/d significantly reduced the risk of relapse in high-relapse-risk patients compared with placebo, reducing the relapse rate from 71% to 55%, but was ineffective in preventing recurrence of inactive Crohn's disease following surgical resection. Mesalamine 4 g/d was effective in decreasing weaning failure due to steroid dependence by 67%, although the relapse rate was not significant compared with placebo at the end of 12 months. Following surgical resection, mesalamine was unable to significantly reduce the incidence of recurrence compared with placebo at the end of 1 year. In patients with active ulcerative colitis, oral mesalamine 2 and 4 g/d was superior to placebo in inducing remission compared with placebo. Among patients with prior steroid of sulfasalazine treatment, rectal mesalamine 4 g hs achieved a remission rate of 78% in more than 12 weeks of therapy. Other studies have not found a dose-response relationship with lower dosages of mesalamine. Whereas nicotine 15-25 mg/d administered as a transdermal patch produced greater symptomatic improvement in active ulcerative colitis compared with placebo, nicotine 15 mg/16 h produced results no different from those with placebo in maintaining remission in active colitis. Nicotine appears to have an adverse effect on the course of Crohn's disease and is not recommended. CONCLUSIONS: Mesalamine has demonstrated clinical effectiveness as a therapeutic agent in the treatment of active ulcerative colitis and inactive Crohn's disease. Although its relationship to inflammatory bowel disease has been known for many years, the usefulness of nicotine for the treatment of active ulcerative colitis requires further exploration before it can be recommended as therapeutic agent.

[Disturbances of craniofacial growth in cleft lip and palate. Local and general factors]. / Gli squilibri di crescita cranio-facciale nei portatori di esiti di LPS. Fattori locali e fattori generali.

The Authors describe and analyze the anomaly of the cranio-facial growth in cleft lip and palate patients and emphasize the importance of proper surgical timing.