Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
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For treatment studies of an infectious disease, such as pneumonia, microbiologic eradication is the logical primary end point. Several problems for pneumonia in general and several more specific to VAP preclude the use of microbiologic eradication as a primary end point. These problems include no positive culture result at baseline, difficulty distinguishing colonization from infection on baseline cultures, no specimen available for testing when determining cure, and induction of colonization by antibiotic treatment. ⋯ Although promising, especially for open-label studies focused on multidrug-resistant pathogens, further research is needed before serial quantitative cultures can be used to define microbiologic failure. Of the biomarkers, procalcitonin level may be a valuable adjunct to clinical evaluation but cannot be a primary end point alone. A decreasing or low procalcitonin level after initiation of antibiotic treatment correlates well with bacterial eradication.
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Clinical trials of nosocomial pneumonia can include patients with hospital-acquired pneumonia, ventilator-associated pneumonia, and health care-associated pneumonia. All study participants should meet a clinical definition of infection and have some microbiologic confirmation of infection and its etiology. If the trial is to reflect clinical practice and to be practical to conduct, insistence that all patients have bronchoscopic quantitative cultures performed may not be practical. ⋯ All trials should include a protocol to control for standards of care, including timing of initial therapy, recent antibiotic use, local microbiology patterns, duration of therapy, and the use of a de-escalation therapy strategy. Blinding of a trial may not be required if studying a new agent that is more active against multidrug-resistant pathogens than against currently available comparators. Any new agent should meet a noninferiority end point for 30-day mortality, but if superiority is a goal of trial design, end points could be microbiologic eradication, time to microbiologic eradication, prolonged duration of therapy, need to modify initial therapy, and serial evaluation of the arterial oxygen tension to fractional inspired oxygen ratio.
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Hospital-acquired pneumonia and ventilator-associated pneumonia are associated with high rates of morbidity and mortality and are often caused by drug-resistant pathogens. Trials of potential new agents to treat these serious infections are complicated by various factors associated with their design and conduct and the complex underlying conditions of the patients that can potentially obscure determination of treatment benefits. ⋯ Regulatory guidance could help to standardize the design and conduct of trials evaluating potentially efficacious agents. In this article, some of the important challenges that were faced in conducting trials of agents to treat hospital-acquired pneumonia and ventilator-associated pneumonia are described, and areas for which regulatory guidance would be most useful are discussed.
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Background. A need exists for new antimicrobial agents to treat neonates, infants, and children for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) caused by nosocomial antibiotic-resistant pathogens. Current and clear guidance on approval of new agents for all pediatric age groups is lacking. ⋯ Conclusions. Investigation and approval of new agents for HAP and VAP in all pediatric age groups is needed. A uniform definition of HAP and VAP is required that is relevant for clinical trials and balances the risks of experimental therapy and sampling procedures for study patients with potential benefits for both the patient under investigation and the hospitalized children who may develop nosocomial pneumonia.
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Our thesis is a simple one: although a drug can fail in an individual patient for many reasons, appropriately sized and conducted drug-development programs often fail because of insensitive, uninformative end points, and/or poor a priori regimen decisions. The difficulty in successfully developing antimicrobial agents at present is often exacerbated by company decision-makers who are either uninformed or disregard the difference between empirical-based (ie, akin to playing pin-the-tail on the donkey) and quantitative model-based development plans. Frequently, the focus is on Gantt charts (project event schedules) and the on-time submission of a New Drug Application to a regulatory body, such as the US Food and Drug Administration. ⋯ We believe that the goal of drug development is not a New Drug Application submitted on time but, rather, an approved, differentiated, safe, and effective new medicine. Here, we focus on the pharmacokinetic-pharmacodynamic data needed to guide dosing regimen decisions for patients with hospital-acquired bacterial pneumonia or ventilator-associated bacterial pneumonia. Early consideration of these data in development programs will reduce risk not only to sponsors but also, most importantly, to the patients enrolled in the clinical trials.