Ertapenem Therapy for Community-Acquired Pneumonia in the Elderly

Efficacy of Ceftriaxone 1 g daily Versus 2 g daily for The Treatment of Community-Acquired Pneumonia: A Systematic Review with Meta-Analysis

Introduction: Ceftriaxone has been recommended as a first-line treatment for various infections; however, the doses for pneumonia have not been a consensus in randomized clinical trials. To compare ceftriaxone 1 g daily efficacy to other ceftriaxone dosing regimens in community-acquired pneumonia. Area covered: We performed a systematic review and meta-analysis on PubMed, Web of Science, Scopus, and LILACS. Randomized controlled trials of ceftriaxone in community-acquired pneumonia were included. Outcomes included clinical cure in modified intention-to-treatment, clinically and microbiologically evaluable patients. Expert opinion: Ceftriaxone dosages of 1 g daily are as safe and effective as other antibiotic regimens for community-acquired pneumonia. Twenty-four articles fulfilled the inclusion criteria. Twelve studies evaluated ceftriaxone regimens at a dosage of 2 g daily and 12 studies evaluated ceftriaxone at a dosage of 1 g daily. The odds-ratio of clinical cure in the modified intention-to-treatment patients administered either ceftriaxone (4666 patients) or a comparator (4411 patients) was 0.98 (95% CI [0.82-1.17]). Comparator regimens showed similar efficacy to ceftriaxone regimens of 1 g daily, with an odds ratio of 1.03 (95% CI [0.88-1.20]). Dosages higher than ceftriaxone 1 g daily did not result in improved clinical outcomes for community-acquired pneumonia patients (OR 1.02, 95% CI [0.91-1.14]).

Antibiotic expected effectiveness and cost under real life microbiology: evaluation of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia for elderly patients in Spain

Background

Clinical efficacy of antibiotics may be affected by changes in the susceptibility of microorganisms to antimicrobial agents. The purpose of this study is to assess how these changes could affect the initial efficacy of ertapenem and ceftriaxone in the treatment of community-acquired pneumonia (CAP) in elderly patients and the potential consequences this may have in health care costs.

Methods

Initial efficacy in elderly was obtained from a combined analysis of two multicenter, randomized studies. An alternative scenario was carried out using initial efficacy data according to the pneumonia severity index (PSI). Country-specific pathogens distribution was obtained from a national epidemiological study, and microbiological susceptibilities to first- and second-line therapies were obtained from Spanish or European surveillance studies. A decision analytic model was used to compare ertapenem versus ceftriaxone for CAP inpatient treatment. Inputs of the model were the expected effectiveness previously estimated and resource use considering a Spanish national health system perspective. Outcomes include difference in proportion of successfully treated patients and difference in total costs between ertapenem and ceftriaxone. The model performed one-way and probabilistic sensitivity analyses.

Results

First-line treatment of CAP with ertapenem led to a higher proportion of successfully treated patients compared with ceftriaxone in Spain. One-way sensitivity analysis showed that length of stay was the key parameter of the model. Probabilistic sensitivity analysis showed that ertapenem can be a cost-saving strategy compared with ceftriaxone, with a 59% probability of being dominant (lower costs with additional health benefits) for both, elderly patients (>65 years) and patients with PSI >3.

Conclusion

The incorporation of the current antimicrobial susceptibility into the initial clinical efficacy has a significant impact in outcomes and costs in CAP treatment. The treatment with ertapenem compared with ceftriaxone resulted in better clinical outcomes and lower treatment costs for two segments of the Spanish population: elderly patients and patients with severe pneumonia (PSI >3).

Pneumonia in frail older patients: an up to date

Despite advances in diagnosis, antimicrobial therapy and supportive care modalities, community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality, especially in patients who require hospitalization. Elderly patients with poor functional status are characterized by a higher risk of developing severe CAP, due to the frequent presence of underlying respiratory and cardiac diseases, alteration of mental status, and immunosuppression. In recent years, changes in the healthcare system have shifted a considerable part of older patient care from hospitals to the community, and the traditional distinction between community- and hospital-acquired infections has become less clear. Pneumonia occurring among outpatients in contact with the healthcare system has been termed healthcare-associated pneumonia. Older frail patients have a high frequency of aspiration pneumonia and pneumonia due to gram-negative bacilli and other multidrug resistant pathogens. The contemporary presence of renal impairment usually requires specific dose adjustment of antibiotic therapy, which may be toxic in this specific patient population. This review produces a summary of therapeutic recommendations on the basis of the most updated clinical and pharmacological data.

Epileptogenic potential of carbapenem agents: mechanism of action, seizure rates, and clinical considerations

Antimicrobials are the most frequently implicated class of drugs in drug-induced seizure, with β-lactams being the class of antimicrobials most often implicated. The seizure-inducing potential of the carbapenem subclass may be directly related to their β-lactam ring structure. Data on individual carbapenems and seizure activity are scarce. To evaluate the available evidence on the association between carbapenem agents and seizure activity, we conducted a literature search of the MEDLINE (1966-May 2010), EMBASE (1974-May 2010), and International Pharmaceutical Abstracts (1970-May 2010) databases. Reference citations from the retrieved articles were also reviewed. Mechanistically, seizure propensity of the β-lactams is related to their binding to γ-aminobutyric acid (GABA) receptors. There are numerous reports of seizure activity associated with imipenem-cilastatin, with seizure rates ranging from 3-33%. For meropenem, doripenem, and ertapenem, the seizure rate for each agent is reported as less than 1%. However, as their use increases and expands into new patient populations, the rate of seizures with these agents may increase. High-dose therapy, especially in patients with renal dysfunction, preexisting central nervous system abnormalities, or a seizure history increases the likelihood of seizure activity. Although specific studies have not been conducted, data indicate that carbapenem-associated seizure is best managed with benzodiazepines, followed by other agents that enhance GABA transmission. Due to the drug interaction between carbapenems and valproic acid, resulting in clinically significant declines in valproic acid serum concentrations, the combination should be avoided whenever possible. Clinicians should be vigilant regarding the possibility of carbapenem-induced seizures when selecting and dosing antimicrobial therapy.

Community-acquired pneumonia in the elderly

BACKGROUND

Community-acquired pneumonia (CAP) is a frequent cause of hospitalization and death among the elderly.

OBJECTIVE

This article reviews information on CAP among the elderly, including age-related changes, predisposing risk factors, causes, treatment strategies, and prevention.

METHODS

Searches of MEDLINE (January 1990-November 2009), International Pharmaceutical Abstracts (January 1990-November 2009), and Google Scholar were conducted using the terms community-acquired pneumonia, pneumonia, treatment guidelines, and elderly. Additional publications were found by searching the reference lists of the identified articles. Studies that reported diagnostic criteria as well as the treatment outcomes achieved in adult patients with CAP were selected for this review.

RESULTS

Three practice guidelines, 5 reviews, and 43 studies on CAP in the elderly were identified in the literature search. Based on those publications, risk factors that predispose the elderly to pneumonia include comorbid conditions, poor functional and nutritional status, consumption of alcohol, and smoking. The clinical presentation of pneumonia in the elderly (>/=65 years of age) may be subtle, lacking the typical acute symptoms (fever, cough, dyspnea, and purulent sputum) observed in younger adults. Pneumonia should be suspected in all elderly patients who have fever, altered mental status, or a sudden decline in functional status, with or without lower respiratory tract symptoms such as cough, purulent sputum, and dyspnea. Treatment of CAP in the elderly should be guided by the latest recommendations of the Infectious Diseases Society of America and the American Thoracic Society (IDSA/ATS), along with consideration of local rates and patterns of antimicrobial resistance, as well as individual patient risk factors for acquiring less common or more resistant pathogens. Recommended empiric antimicrobial regimens generally consist of either a beta-lactam plus a macrolide or a respiratory fluoroquinolone alone. Adherence to the IDSA/ATS guidelines has been found to improve in-hospital mortality (adherence vs nonadherence, 8%; 95% CI, 7%-10% vs 17%; 95% CI, 14%-20%; P< 0.01), length of hospital stay (8 days; interquartile range [IQR], 5-15 vs 10 days; IQR, 6-24 days, respectively; P < 0.01), and time to clinical stability in elderly patients with CAP (percentage of stable patients by day 7, 71%; 95% CI, 68%-74% vs 57%; 95% CI, 53%-61%, respectively; P < 0.01). All elderly patients should be vaccinated against pneumococcal disease and influenza based on recommendations from the Centers for Disease Control and Prevention. Lifestyle modifications and nutritional support are also important elements in the prevention of pneumonia in the elderly.

CONCLUSION

Adherence to established guidelines, along with customization of antimicrobial therapy based on local rates and patterns of resistance and patient-specific risk factors, likely will improve the treatment outcome of elderly patients with CAP.

In vitro activity of tigecycline and occurrence of tetracycline resistance determinants in isolates from patients enrolled in phase 3 clinical trials for community-acquired pneumonia

The in vitro activity of tigecycline was evaluated against baseline pathogens isolated from patients enrolled in phase 3 clinical trials for community-acquired pneumonia conducted in 29 countries worldwide. Tigecycline was active against the most prevalent pathogens, including Streptococcus pneumoniae (MIC(90) 0.06 mg/L), Staphylococcus aureus (MIC(90) 0.25 mg/L), Haemophilus influenzae (MIC(90) 0.5 mg/L) and Klebsiella pneumoniae (MIC(90) 1 mg/L). Twelve isolates of S. pneumoniae expressing tet(M) and two isolates of K. pneumoniae producing extended-spectrum beta-lactamases isolated during the study were susceptible to tigecycline. The excellent in vitro activity of tigecycline against these clinical isolates confirmed its potential utility against pathogens associated with community-acquired pneumonia.

Comparative costs of ertapenem and cefotetan as prophylaxis for elective colorectal surgery

BACKGROUND AND PURPOSE

The costs of treating surgical site infections can be considerable. There is a cost associated with the prophylactic use of antibiotics; however, the use of prophylactic agents may reduce infection rates and lengths of stay, thus offsetting the overall treatment cost and potentially generating cost savings to hospitals. This project was intended to determine the potential cost impact of using ertapenem 1 g vs. cefotetan 2 g as prophylaxis for elective colorectal surgery.

METHODS

Cost analysis using efficacy data from the PREVENT clinical trial and drug acquisition and total hospital costs in 2005 dollars from Premier's Perspective Comparative Database in patients > or = 18 year of age, evaluable at four weeks after elective surgery of the colon or rectum and prophylactic treatment with ertapenem (n = 338) or cefotetan (n = 334). The primary outcome measures were the rate of prophylactic drug failure and the difference between the ertapenem and cefotetan groups in costs related to and total hospital stay. Prophylactic failure was defined as a surgical site infection, unexplained antibiotic use, or anastomotic leak.

RESULTS

Prophylactic failure occurred in 28.1% of the patients receiving ertapenem and 42.8% of those receiving cefotetan (p < 0.05). The most common prophylactic failure was surgical site infection: 18.3% for ertapenem, 31.1% for cefotetan, difference (95% confidence interval) -13.0% (-19.5, -6.5%) (p < 0.05). The mean +/- standard deviation length of stay for all patients, including prophylactic successes and failures, was 7.6 +/- 6.6 days for ertapenem and 8.7 +/- 9.5 days for cefotetan. The mean per-patient cost of prophylactic drugs and hospital room and board was $15,245 with ertapenem and $17,428 cefotetan, a net difference of -$2,181.

CONCLUSIONS

Ertapenem used in prophylaxis for elective colorectal operations results in a lower rate of surgical site infection and a shorter average length of stay than cefotetan. The calculated net difference in prophylactic antibiotic drug and hospital costs represents a saving of $2,181 per patient with ertapenem relative to cefotetan.

Ertapenem versus cefepime for initial empirical treatment of pneumonia acquired in skilled-care facilities or in hospitals outside the intensive care unit

The study presented here compared the efficacy and safety of ertapenem and cefepime as initial treatment for adults with pneumonia acquired in skilled-care facilities or in hospital environments outside the intensive care unit (ICU). Non-ventilated patients developing pneumonia in hospital environments outside the ICU, in nursing homes, or in other skilled-care facilities were enrolled in this double-blind non-inferiority study, stratified by APACHE II score (<or=15 vs >15) and randomized (1:1) to receive cefepime (2 g every 12 h with optional metronidazole 500 mg every 12 h) or ertapenem (1 g daily). After 3 days of parenteral therapy, participants demonstrating clinical improvement could be switched to oral ciprofloxacin or another appropriate oral agent. Probable pathogens were identified in 162 (53.5%) of the 303 randomized participants. The most common pathogens were Enterobacteriaceae, Streptococcus pneumoniae, and Staphylococcus aureus, isolated from 59 (19.5%), 39 (12.9%), and 35 (11.6%) participants, respectively. At the test-of-cure assessment 7-14 days after completion of all study therapy, pneumonia had resolved or substantially improved in 89 (87.3%) of 102 clinically evaluable ertapenem recipients and 80 (86%) of 93 clinically evaluable cefepime recipients (95% confidence interval for the difference, -9.4 to 11.8%), fulfilling pre-specified criteria for statistical non-inferiority. The frequency and severity of drug-related adverse events were generally similar in both treatment groups. In this study population, ertapenem was as well-tolerated and efficacious as cefepime for the initial treatment of pneumonia acquired in skilled-care facilities or in hospital environments outside the ICU.

Ertapenem: the new carbapenem 5 years after first FDA licensing for clinical practice

Ertapenem, a parenteral broad-spectrum 1-beta-methyl-carbapenem, was licensed 5 years ago for clinical practice in the US and Europe. The substance has a good in vitro activity against many common aerobic and anaerobic Gram-positive and -negative bacteria. Its in vitro activity against Enterobacteriaceae carrying plasmid- or chromosomal-mediated beta-lactamases, including AmpC- and extended-spectrum beta-lactamases, is especially clinically significant. Advantages concerning in vitro activity and low potential for so-called 'collateral damage', and development of own resistance during therapy, as shown in several randomized, controlled clinical trials, make ertapenem an excellent treatment choice for complicated aerobic and anaerobic mix infections caused by ertapenem-sensitive bacteria. On the other hand, due to its limited activity against Acinetobacter spp., enterococci and Pseudomonas aeruginosa, it is less suitable for late-onset nosocomial infections. International guidelines recommend the initial empirical use of ertapenem for intra-abdominal infections, skin and skin-structure infections, acute pelvic infections, complicated urinary tract infections and pneumonia (both community-acquired and 'early-onset' nosocomial) in a dose of 1.0 g administered once daily. However, recent results from pharmacokinetic/pharmacodynamic modelling studies in critically ill patients with ventilator-associated pneumonia and adipose volunteers with a body mass index of > or = 20 kg/m(2) showed that the standard dose of 1.0 g/day may not provide adequate free, protein-unbound drug concentrations in plasma and organ tissues. Therefore, a shortening of the dosage interval or continuous infusion of ertapenem should be considered to ensure optimal free concentrations in these particular populations.

Pneumonies aiguës communautaires : analyse critique des essais cliniques

Optimal antibiotic treatment of community-acquired pneumonia (CAP) remains controversial. The clinical impact of S. pneumoniae resistance to macrolides is well documented. By contrast high dosage amoxicillin (1 g tid) remains active against such strains and no failure has been reported. The aim of this paper was to review clinical trials in community-acquired pneumonia, published from January 1, 1999, to December 31, 2005. One hundred seventy-three articles were collected, using Medline, 35 of which were analyzed, and 16 finally used. Telithromycin and pristinamycin may be used in mild to moderate CAP. Anti-pneumococcal fluoroquinolones such as levofloxacin and moxifloxacin may be used in at risk patients, but levofloxacin has only been investigated in patients with severe CAP and patients with Legionnaire's disease. Amoxicillin 1 g tid remains the drug of choice for pneumococcal CAP.

Evaluation of the in vitro activity of ertapenem and nine other comparator agents against 337 anaerobic bacteria

Ertapenem activity in vitro was compared with that of nine reference antibiotics against 337 anaerobes by determining minimal inhibition concentrations (MICs). Amongst 246 Gram-negative anaerobes, 4, 8, 3, 4, 7, 2 and 52 strains showed resistance to ertapenem, amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoxitin, imipenem and clindamycin, respectively, and all strains were inhibited by metronidazole. Ertapenem MIC(50) values were 0.5, 0.25, 0.06 and <or=0.03mg/L for the Bacteroides fragilis group, Prevotella spp., fusobacteria and Gram-positive cocci, respectively. Overall resistance rates were 2.1%, 51.3%, 2.4%, 1.2%, 1.5%, 7.1%, 0.6%, 22% and 1.5% for ertapenem, amoxicillin, amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefoxitin, imipenem, clindamycin and metronidazole, respectively. Ertapenem showed a broad spectrum and good activity against anaerobes.

Ertapenem: a review of its use in the treatment of bacterial infections

The Group 1, 1 beta-methyl carbapenem ertapenem (Invanz) is approved for parenteral use in patients with complicated intra-abdominal infection (cIAI), community-acquired pneumonia (CAP) and acute pelvic infection caused by susceptible strains of certain designated organisms in both the US and the EU. Additional approved indications in the US include complicated skin and skin structure infection (cSSSI) and complicated urinary tract infection (cUTI). Ertapenem is approved for use in adults in both the US and the EU and in paediatric patients aged >or=3 months in the US. Ertapenem has a broad spectrum of in vitro activity against Gram-negative pathogens, including extended-spectrum beta-lactamase (ESBL)- and AmpC-producing Enterobacteriaceae, Gram-positive pathogens and anaerobic pathogens. It has similar efficacy to comparator antibacterials such as piperacillin/tazobactam in cSSSI (including diabetic foot infection), cIAI and acute pelvic infection and ceftriaxone with or without metronidazole in cIAI, cUTI and CAP. The drug has also shown efficacy in the treatment of paediatric patients with complicated community-acquired bacterial infections. Ertapenem has a convenient once-daily administration schedule and is generally well tolerated. Thus, ertapenem is an important option for the empirical treatment of complicated community-acquired bacterial infections in hospitalised patients.

A multicenter, randomized, double-blind, retrospective comparison of 5- and 10-day regimens of levofloxacin in a subgroup of patients aged ≥65 years with community-acquired pneumonia

OBJECTIVE

This subgroup analysis sought to determine the efficacy and tolerability of a 5-day regimen of levofloxacin 750 mg/d compared with a 10-day regimen of levofloxacin 500 mg/d in the treatment of community-acquired pneumonia (CAP) in elderly patients (aged > or =65 years).

METHODS

This subgroup analysis was based on the outcomes in patients aged > or =65 years from a randomized, double-blind, controlled trial conducted at 70 US centers. Patients in Pneumonia Severity Index (PSI) class I/II and III/IV were randomized to receive levofloxacin 750 mg/d for 5 days or levofloxacin 500 mg/d for 10 days. Study investigators assessed clinical and microbiologic outcomes 7 to 14 days after administration of the last dose of medication and collected adverse events for 30 days after the last dose.

RESULTS

This analysis included 177 elderly patients, 80 receiving levofloxacin 750 mg/d for 5 days and 97 receiving levofloxacin 500 mg/d for 10 days. Although most demographic and baseline clinical characteristics were comparable between the 2 groups, the group that received levofloxacin 500 mg/d was older than the group that received levofloxacin 750 mg/d (median age, 76.0 vs 72.5 years, respectively; P = 0.029) and had a higher mean PSI score (90.7 vs 83.1; P = 0.017). Despite the halved duration of therapy, unadjusted clinical success rates were comparable between the 2 groups (89.0% and 91.9% in the 750- and 500-mg arms, respectively; 95% CI, -7.1 to 12.7). Microbiologic eradication rates were 90.3% (28/31) in the 750-mg arm and 87.5% (14/16) in the 500-mg arm (P = NS). Multivariate analysis adjusting for baseline PSI score indicated that treatment assignment was not statistically associated with clinical success (adjusted odds ratio for clinical success with 500-mg dose, 1.92; 95% CI, 0.62 to 5.99). The incidence of treatment-emergent adverse events did not differ between the 2 study treatments. The most common adverse events in both groups were insomnia, constipation, and headache.

CONCLUSIONS

This subgroup analysis found that levofloxacin 750 mg/d for 5 days was well tolerated in the treatment of CAP in elderly patients. Undajusted and adjusted rates of clinical success were statistically similar between levofloxacin 750 mg/d for 5 days and levofloxacin 500 mg/d for 10 days.

Ertapenem: review of a new carbapenem

The carbapenems are beta-lactam-type antibiotics with an exceptionally broad spectrum of activity. Ertapenem is a new carbapenem developed to address the pharmacokinetic shortcomings (short half-life) of imipenem and meropenem. Ertapenem shares similar structural features with meropenem, including its stability to dehydropeptidase-1, allowing it to be administered without a dehydropeptidase-1 inhibitor. Ertapenem, like imipenem and meropenem, demonstrates broad-spectrum antimicrobial activity against many Gram-positive and -negative aerobes and anaerobes and is resistant to nearly all beta-lactamases, including extended-spectrum beta-lactamases and AmpCs. However, it differs from both imipenem and meropenem in demonstrating limited activity against Enterococcusspp., Pseudomonasaeruginosa and other nonfermentative Gram-negative bacteria commonly associated with nosocomial infections. The extensive protein binding of ertapenem extends the half-life and allows for once-daily dosing. Prospective, multicenter, randomized, double-blind, comparative clinical studies demonstrate similar clinical efficacy of ertapenem compared with other agents. Clinical trials of complicated intra-abdominal infection, acute pelvic infection, complicated skin and soft-structure infection, community-acquired pneumonia and complicated urinary tract infections demonstrated that ertapenem has equivalent efficacy and safety compared with ceftriaxone and piperacillin/tazobactam. Ertapenem is a promising new carbapenem with excellent efficacy and safety for the treatment of a variety of community-acquired infections. It also appears to be of great value as an outpatient parenteral antimicrobial therapy.