Pharmacokinetic/pharmacodynamic target attainment analyses to support intravenous and oral lefamulin dose selection for the treatment of patients with community-acquired bacterial pneumonia.

OBJECTIVES: Lefamulin is a semi-synthetic intravenous (iv) and oral pleuromutilin antibiotic active against community-acquired bacterial pneumonia (CABP) pathogens. Pharmacokinetic/pharmacodynamic (PK/PD) target attainment analyses were carried out to evaluate lefamulin 150 mg iv q12h and 600 mg orally q12h under fed and fasted conditions for the treatment of patients with CABP. METHODS: The analyses undertaken used a population PK model based on Phase 1 PK data, non-clinical PK/PD targets for efficacy and in vitro surveillance data for Streptococcus pneumoniae (SP) and Staphylococcus aureus (SA), and Monte Carlo simulation. Percentage probabilities of PK/PD target attainment by MIC on day 1 were determined using median total-drug epithelial lining fluid (ELF) and free-drug plasma AUC:MIC ratio targets associated with 1 and 2 log10 cfu reductions from baseline. RESULTS: Percentage probabilities of attaining the total-drug ELF AUC:MIC ratio target for a 1 log10 cfu reduction from baseline for SP were ≥99.2% at the MIC90 of 0.12 mg/L and 96.7%, 82.1% and 96.3% for iv and oral dosing regimens under fed and fasted conditions, respectively, at the MIC99 of 0.25 mg/L. Percentage probabilities of attaining the free-drug plasma AUC:MIC target for the same endpoint at the SP MIC99 were 100% for each regimen. For the SA MIC90 of 0.12 mg/L and AUC:MIC ratio targets for the same endpoint, percentage probabilities were 92.7%-100% for iv and oral dosing regimens. CONCLUSIONS: These data provide support for lefamulin 150 mg iv q12h and 600 mg orally q12h for the treatment of patients with CABP and suggest that doses may not need to be taken under fasted conditions.

Evaluation of Daptomycin Exposure and Efficacy and Safety Endpoints To Support Risk-versus-Benefit Considerations.

The choice of an antimicrobial agent must balance optimization of efficacy endpoints with the minimization of safety events. The risk versus benefit of daptomycin for patients with Staphylococcus aureus bacteremia with or without infective endocarditis receiving daptomycin at 6, 8, and 10 mg/kg of body weight/day was assessed. The relationships between the area under the concentration-time curve over 24 h (AUC)/MIC ratio and both clinical response and time to decreased susceptibility were evaluated using data from patients with such infections who received daptomycin at 6 mg/kg/day. Using these relationships, plus the previously identified relationship between the minimum concentration and an elevation in the creatine phosphokinase (CPK) concentration (CPK elevation) (S. M. Bhavnani, C. M. Rubino, P. G. Ambrose, and G. L. Drusano, Clin Infect Dis 50:1568-1574, 2010) and Monte Carlo simulation, the probability of each outcome by MIC for daptomycin at 6, 8, and 10 mg/kg/day was calculated. The function for exposure-response relationships for clinical response (P = 0.06) and time to decreased susceptibility (P = 0.01) resembled U and inverted U shapes, respectively. Multivariable analyses demonstrated AUC/MIC ratio, creatinine clearance, albumin concentration, and disease category to be predictors of clinical response. The results of simulations failed to demonstrate large improvements in the probabilities of clinical success among cohorts of simulated patients defined by the above-described predictive factors or the probability of decreased susceptibility at 30 days when the daptomycin dose was increased from 6 to 10 mg/kg/day. The probability of CPK elevation increased from 0.073 to 0.156 over this dose range. These data can be used to inform risk-versus-benefit decisions for daptomycin dose selection in patients with S. aureus bacteremia with or without infective endocarditis. The risk of CPK elevation, which is reversible, should be weighed in the context of the mortality and severe morbidity associated with these types of serious staphylococcal infections.

Use of pharmacokinetic-pharmacodynamic analyses to optimize therapy with the systemic antifungal micafungin for invasive candidiasis or candidemia.

Echinocandins have become a first-line therapy for invasive candidiasis (IC). Using phase 3 trial data for patients with IC, pharmacokinetic-pharmacodynamic (PK-PD) relationships for efficacy for micafungin were examined. Micafungin exposures were estimated using a population pharmacokinetic model, and univariable and multivariable logistic regressions were used to identify factors associated with outcome, including the micafungin area under the concentration-time curve (AUC)/MIC ratio. Monte Carlo simulation was used to evaluate the probability of achieving AUC/MIC ratios associated with efficacy. Mycological and clinical success rates for evaluable cases were 89.4 and 90.9, respectively. MIC50s and MIC90s for Candida species inhibition were 0.008 and 0.5 mg/liter, respectively. The median AUC/MIC ratio was 15,511 (range, 41.28 to 98,716). Univariable analyses revealed a significant relationship between the AUC/MIC ratio and mycological response, with the worst response being among patients with lower (≤3,000) AUC/MIC ratios (P=0.005). For patients with Candida parapsilosis, AUC/MIC ratios of ≥285 were predictive of a higher mycological response (P=0.11). Multivariable logistic regression demonstrated the AUC/MIC ratio, APACHE II score, and history of corticosteroid use to be significant independent predictors of a favorable response. PK-PD target attainment analyses suggested that 76.7% and 100% of patients would achieve an AUC/MIC ratio of ≥3,000 for an MIC of 0.03 mg/liter and an AUC/MIC ratio of ≥285 for an MIC of <0.5 mg/liter, respectively. The identification of a lower AUC/MIC ratio target for C. parapsilosis than other Candida species suggests consideration of species-specific echinocandin susceptibility breakpoints and values that are lower than those currently approved by regulatory agencies.

Tubal anastomosis by robotic compared with outpatient minilaparotomy.

OBJECTIVE: To compare tubal anastomosis by robotic system compared with outpatient minilaparotomy. METHODS: In this retrospective case-control study, women were identified by current procedural terminology code for tubal anastomosis. We included all cases of tubal anastomosis for reversal of a prior tubal ligation by either outpatient minilaparotomy or robotic system technique. Cases performed by laparoscopy without aid of the robot were excluded. Comparisons were based on Fisher's exact, chi(2), and Wilcoxon rank sum tests. RESULTS: There were 26 cases of tubal anastomosis performed with the robot and 41 cases performed by outpatient minilaparotomy. The two groups were comparable in age, body mass index, and parity. Anesthesia time for the robotic technique (median with interquartile range) was 283 (267-290) minutes compared with 205 (170-230) minutes with outpatient minilaparotomy (P<.001). Surgical times for the robot and minilaparotomy were 229 (205-252) minutes and 181 (154-202) minutes respectively (P=.001). Hospitalization times, pregnancy, and ectopic pregnancy rates were not significantly different. The robotic technique was more costly. The median difference in costs of the procedures was $1,446 (95% confidence interval $1,112-1,812) (P<.001). The time to return to work was significantly shorter in the robotic system group by approximately 1 week (P=.013). CONCLUSION: Robotic surgery for tubal anastomosis was successfully accomplished without conversion to laparotomy. The robotic technique for tubal anastomosis required significantly prolonged surgical and anesthesia times over outpatient minilaparotomy (P

Clinical outcomes and cost analysis of a "fast track" postoperative care pathway for ileal pouch-anal anastomosis: a case control study.

PURPOSE: Traditional length of hospital stay after ileal pouch-anal anastomosis is 8 to 15 days. Fast track rehabilitation programs reduce stay, but there are concerns that readmission and complication rates may be increased. This study evaluated a fast track pathway after ileoanal pouch surgery. METHODS: One hundred three consecutive patients underwent ileal pouch-anal anastomosis on two colorectal services using a fast track protocol with early ambulation, diet, and defined discharge criteria. Direct hospital costs and 30-day and long-term complication data were collected. Patients were matched to controls managed with traditional care pathways by other colorectal staff. RESULTS: Matching was established for 97 patients. Fast track patients had shorter hospital stay than controls (median 4 vs. 5 days; mean 5.0 vs. 5.9, P = 0.012). Readmission and recurrent operation rates were similar (24 vs. 20 percent, P = 0.49, and 9 vs. 10 percent, P = 0.8, fast track vs. control, respectively). Median direct costs per patient (US$) within 30 days were lower with fast track (5692 vs. 6672, P = 0.001), primarily because of reductions in postoperative management expenses. Complication rates, including pouch failure, bowel obstruction, pouchitis, and anastomotic stricture were comparable. Early discharge (< or = 5 days from surgery) occurred in 79 (77 percent) fast track patients. Failure with early discharge was associated with male gender, reoperations, and anastomotic complications. CONCLUSIONS: Fast track protocol after ileoanal pouch surgery reduces length of stay and hospital costs without increasing complication rates. Successful early discharge usually signals a benign postoperative course.

Use of pharmacokinetic-pharmacodynamic target attainment analyses to support phase 2 and 3 dosing strategies for doripenem.

A doripenem population pharmacokinetic model and Monte Carlo simulations were utilized for dose regimen decision support for future clinical development. Simulation results predict that 500 mg of doripenem administered over 1 h every 8 h would be effective against bacterial strains with MICs less than 2 microg/ml and that less susceptible strains could be treated with prolonged infusions.

A pilot study of health education via a nurse-run telephone self-management programme for elderly people with osteoarthritis.

We conducted a pilot study of a nurse-run telephone self-management programme for elderly people with osteoarthritis (OA). Thirty-two subjects, aged 60 years or more, with a diagnosis of OA were recruited from two hospital rheumatology clinics and were randomized to a control or intervention group. The intervention group received six weekly mailings of OA health education modules, a relaxation audio-tape and six weekly 45 min follow-up telephone self-management sessions. There was a 100% compliance rate in the intervention group, and all subjects completed baseline and three-month interviews; one subject in each group was lost to six-month follow-up. There were no significant differences in self-management between the control and intervention groups. However, at three months there were improvements in the intervention group (relative to baseline) on some outcome measures. The results suggest that the telephone may be a useful tool for reinforcing health-promoting activities for patients.