cIn a previous phase 3 study, the cure rates that occurred in patients with hospital-acquired pneumonia treated with tigecycline at the approved dose were lower than those seen with patients treated with imipenem and cilastatin (imipenem/cilastatin). We hypothesized that a higher dose of tigecycline is necessary in patients with hospital-acquired pneumonia. This phase 2 study compared the safety and efficacy of two higher doses of tigecycline with imipenem/cilastatin in subjects with hospital-acquired pneumonia. Subjects with hospital-acquired pneumonia were randomized to receive one of two doses of tigecycline (150 mg followed by 75 mg every 12 h or 200 mg followed by 100 mg every 12 h) or 1 g of imipenem/cilastatin every 8 h. Empirical adjunctive therapy was administered for initial coverage of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa infection, depending on the randomization regimen. Clinical response, defined as cure, failure of treatment, or indeterminate outcome, was assessed 10 to 21 days after the last day of therapy. In the clinically evaluable population, clinical cure with tigecycline 100 mg (17/20, 85.0%) was numerically higher than with tigecycline 75 mg (16/23, 69.6%) and imipenem/cilastatin (18/24, 75.0%).No new safety signals with the high-dose tigecycline were identified. A numerically higher clinical response was observed with the 100-mg dose of tigecycline. This supports our hypothesis that a higher area under the concentration-time curve over 24 h in the steady state divided by the MIC (AUC/MIC ratio) may be necessary to achieve clinical cure in patients with hospital-acquired pneumonia. Further studies are necessary. (The ClinicalTrials.gov identifier for this clinical trial is NCT00707239.) H ospital-acquired pneumonia (HAP) remains an important problem in the care of critically ill patients and has significant clinical and economic consequences, including a 30% to 70% mortality rate (1-4). Mortality among patients with HAP associated with mechanical ventilation is approximately twice that of patients with HAP not associated with mechanical ventilation (5). The initial management of patients with HAP includes obtaining appropriate respiratory samples for culture and sensitivity and initiating therapy with broad-spectrum antibiotics that are active against likely pathogens (6).Tigecycline has a broad spectrum of antibacterial activity (7), including activity against many multidrug-resistant organisms and efficacy in treatment of community-acquired pneumonia (8-10). A single-dose study that collected lung tissue from uninfected subjects undergoing elective surgery showed a ratio of lung area under the concentration time-curve (AUC) to serum AUC, which is also known as lung penetration, of 2.0 (11). Results from a multiple-dose study with tigecycline that measured serum, pulmonary epithelial lining fluid (ELF), and alveolar cell concentrations in healthy volunteers demonstrated ELF penetration of 1.32 (12). These results, together with the observation by Crandon e...
Pneumococcal serotypes causing noninvasive pneumonia in adults may differ significantly from those causing invasive disease, with PCV7-associated serotypes overrepresented. Serotype 5, rarely seen in contemporary surveillance of invasive disease in the United States, substantially contributed to the observed cases of S. pneumoniae-positive CAP or HCAP.
In 12 of 13 phase 3 and 4 comparative clinical trials, all-cause mortality was higher in the tigecycline group versus the comparator group. Study-level mortality risk differences were pooled using a random-effects meta-analysis. Statistical models evaluated the association between patient-level all-cause mortality and baseline factors using logistic regression, recursive partitioning [classification and regression tree (CART) analysis] and survival techniques. The estimated risk difference (tigecycline minus comparator) in all-cause mortality from the meta-analysis was 0.6% (95% confidence interval 0.1-1.2%). Statistical modelling identified baseline bacteraemia associated with mortality only in the tigecycline group. In patients with ventilator-associated pneumonia (VAP) and baseline bacteraemia, mortality was 50.0% (9/18) for tigecycline versus 7.7% (1/13) for the comparator group. Study-level and patient-level analyses have identified that patients in the hospital-acquired pneumonia trial, particularly those with VAP with baseline bacteraemia, were at a higher risk of clinical failure and mortality.
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