A Phase 1 Study of the Safety, Tolerability, and Pharmacokinetics of Single Ascending Doses of a First-in-Human Engineered Cationic Peptide, PLG0206, Intravenously Administered in Healthy Subjects.

In this first-in-human study, PLG0206, a novel engineered cationic antimicrobial peptide, was evaluated for safety, tolerability, and pharmacokinetics (PK) when intravenously (i.v.) administered as a single dose to healthy subjects. Six cohorts of 8 subjects each received escalating single i.v. infusions of PLG0206 at 0.05, 0.125, 0.25, 0.5, or 1 mg/kg dose or placebo over 1 to 4 h. Subjects were randomized to receive either PLG0206 (6 per cohort) or placebo (2 per cohort). Serial pharmacokinetic samples were taken prior to infusion and up to 48 h postinfusion. Safety and tolerability were assessed throughout the study. The demographic characteristics of subjects were comparable between those treated with PLG0206 and placebo and between dose groups. The incidence of treatment-emergent adverse events (TEAE) related to PLG0206 was low, and most events were mild in severity and were similar between the PLG0206 treatment and placebo groups. The most common adverse events reported for PLG0206 were infusion-related reactions, which were mitigated with increasing infusion time and volume. There were no severe adverse events (SAEs), life-threatening events, or deaths throughout the study. i.v. PLG0206 exhibited linear pharmacokinetics over the dose range of 0.05 to 1.0 mg/kg. The median terminal half-life (t1/2) ranged from 7.37 to 19.97 h. Following a single i.v. infusion to healthy subjects, PLG0206 was safe and well tolerated and exhibited linear PK at doses ranging from 0.05 to 1 mg/kg. These findings support the ongoing development of i.v. PLG0206 as an antimicrobial agent.

Once-Daily Plazomicin for Complicated Urinary Tract Infections.

BACKGROUND: The increasing multidrug resistance among gram-negative uropathogens necessitates new treatments for serious infections. Plazomicin is an aminoglycoside with bactericidal activity against multidrug-resistant (including carbapenem-resistant) Enterobacteriaceae. METHODS: We randomly assigned 609 patients with complicated urinary tract infections (UTIs), including acute pyelonephritis, in a 1:1 ratio to receive intravenous plazomicin (15 mg per kilogram of body weight once daily) or meropenem (1 g every 8 hours), with optional oral step-down therapy after at least 4 days of intravenous therapy, for a total of 7 to 10 days of therapy. The primary objective was to show the noninferiority of plazomicin to meropenem in the treatment of complicated UTIs, including acute pyelonephritis, with a noninferiority margin of 15 percentage points. The primary end points were composite cure (clinical cure and microbiologic eradication) at day 5 and at the test-of-cure visit (15 to 19 days after initiation of therapy) in the microbiologic modified intention-to-treat population. RESULTS: Plazomicin was noninferior to meropenem with respect to the primary efficacy end points. At day 5, composite cure was observed in 88.0% of the patients (168 of 191 patients) in the plazomicin group and in 91.4% (180 of 197 patients) in the meropenem group (difference, -3.4 percentage points; 95% confidence interval [CI], -10.0 to 3.1). At the test-of-cure visit, composite cure was observed in 81.7% (156 of 191 patients) and 70.1% (138 of 197 patients), respectively (difference, 11.6 percentage points; 95% CI, 2.7 to 20.3). At the test-of-cure visit, a higher percentage of patients in the plazomicin group than in the meropenem group were found to have microbiologic eradication, including eradication of Enterobacteriaceae that were not susceptible to aminoglycosides (78.8% vs. 68.6%) and Enterobacteriaceae that produce extended-spectrum ß-lactamases (82.4% vs. 75.0%). At late follow-up (24 to 32 days after initiation of therapy), fewer patients in the plazomicin group than in the meropenem group had microbiologic recurrence (3.7% vs. 8.1%) or clinical relapse (1.6% vs. 7.1%). Increases in serum creatinine levels of 0.5 mg or more per deciliter (≥40 µmol per liter) above baseline occurred in 7.0% of patients in the plazomicin group and in 4.0% in the meropenem group. CONCLUSIONS: Once-daily plazomicin was noninferior to meropenem for the treatment of complicated UTIs and acute pyelonephritis caused by Enterobacteriaceae, including multidrug-resistant strains. (Funded by Achaogen and the Biomedical Advanced Research and Development Authority; EPIC ClinicalTrials.gov number, NCT02486627.).

Ceftolozane/Tazobactam Plus Metronidazole for Complicated Intra-abdominal Infections in an Era of Multidrug Resistance: Results From a Randomized, Double-Blind, Phase 3 Trial (ASPECT-cIAI).

BACKGROUND: Increasing antimicrobial resistance among pathogens causing complicated intra-abdominal infections (cIAIs) supports the development of new antimicrobials. Ceftolozane/tazobactam, a novel antimicrobial therapy, is active against multidrug-resistant Pseudomonas aeruginosa and most extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae. METHODS: ASPECT-cIAI (Assessment of the Safety Profile and Efficacy of Ceftolozane/Tazobactam in Complicated Intra-abdominal Infections) was a prospective, randomized, double-blind trial. Hospitalized patients with cIAI received either ceftolozane/tazobactam (1.5 g) plus metronidazole (500 mg) every 8 hours or meropenem (1 g) every 8 hours intravenously for 4-14 days. The prospectively defined objectives were to demonstrate statistical noninferiority in clinical cure rates at the test-of-cure visit (24-32 days from start of therapy) in the microbiological intent-to-treat (primary) and microbiologically evaluable (secondary) populations using a noninferiority margin of 10%. Microbiological outcomes and safety were also evaluated. RESULTS: Ceftolozane/tazobactam plus metronidazole was noninferior to meropenem in the primary (83.0% [323/389] vs 87.3% [364/417]; weighted difference, -4.2%; 95% confidence interval [CI], -8.91 to .54) and secondary (94.2% [259/275] vs 94.7% [304/321]; weighted difference, -1.0%; 95% CI, -4.52 to 2.59) endpoints, meeting the prespecified noninferiority margin. In patients with ESBL-producing Enterobacteriaceae, clinical cure rates were 95.8% (23/24) and 88.5% (23/26) in the ceftolozane/tazobactam plus metronidazole and meropenem groups, respectively, and 100% (13/13) and 72.7% (8/11) in patients with CTX-M-14/15 ESBLs. The frequency of adverse events (AEs) was similar in both treatment groups (44.0% vs 42.7%); the most common AEs in either group were nausea and diarrhea. CONCLUSIONS: Treatment with ceftolozane/tazobactam plus metronidazole was noninferior to meropenem in adult patients with cIAI, including infections caused by multidrug-resistant pathogens. CLINICAL TRIALS REGISTRATION: NCT01445665 and NCT01445678.

Multicenter, double-blind, randomized, phase II trial to assess the safety and efficacy of ceftolozane-tazobactam plus metronidazole compared with meropenem in adult patients with complicated intra-abdominal infections.

Ceftolozane-tazobactam (TOL-TAZ) is a novel antibacterial with activity against Pseudomonas aeruginosa and other common Gram-negative pathogens, including extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae, that are associated with complicated intra-abdominal infections (cIAIs). This prospective, double-blind, randomized, multicenter, phase II trial assessed patient clinical and microbiological responses to and the safety of TOL-TAZ plus metronidazole compared with those of meropenem. Hospitalized adults with cIAIs that required surgical intervention were randomized (2:1) to receive intravenous (i.v.) TOL-TAZ (1.5 g [containing 1,000 mg TOL and 500 mg TAZ] every 8 h [q8h]) with or without i.v. metronidazole (500 mg q8h) or i.v. meropenem (1 g q8h) for 4 to 7 days. The primary endpoint was the clinical response at the test-of-cure visit in the microbiologically modified intent-to-treat (mMITT) and microbiologically evaluable (ME) populations. Secondary measures included the patients' microbiological response and safety. In total, 82 patients received TOL-TAZ (90.2% with metronidazole), and 39 received meropenem. For the mMITT population, clinical cure was seen in 83.6% of the patients (51/61; 95% confidence interval [CI], 71.9 to 91.8) who received TOL-TAZ and 96.0% of the patients (24/25; 95% CI, 79.6 to 99.9) who received meropenem (difference, -12.4%; 95% CI, -34.9% to 11.1%); in the ME population, clinical cure was seen in 88.7% and 95.8% of the patients (difference, -7.1%; 95% CI, -30.7% to 16.9%) who received TOL-TAZ and meropenem, respectively. TOL-TAZ demonstrated microbiological success against Escherichia coli (89.5%), Klebsiella pneumoniae (100%), and P. aeruginosa (100%). The adverse event rates were similar in the groups (50.0% with TOL-TAZ and 48.8% with meropenem). TOL-TAZ in combination with metronidazole was well tolerated and resulted in clinical and microbiological success rates supportive of further clinical development in patients with cIAIs. (This study has been registered at ClinicalTrials.gov under registration no. NCT01147640.).

Pharmacokinetics and safety of intravenous ceftolozane-tazobactam in healthy adult subjects following single and multiple ascending doses.

The pharmacokinetics and safety of ceftolozane, a novel cephalosporin, and tazobactam, a ß-lactamase inhibitor, alone and in combination as a 2:1 ratio in single doses of up to 2,000 and 1,000 mg of ceftolozane and tazobactam, respectively, and multiple doses of up to 3,000 and 1,500 mg of ceftolozane and tazobactam, respectively, per day were evaluated in healthy adult subjects. In part 1, groups of six subjects each received single ascending doses of ceftolozane, tazobactam, and ceftolozane-tazobactam in a within-cohort crossover design. In part 2, groups of 5 or 10 subjects each received multiple doses of ceftolozane, tazobactam, or ceftolozane-tazobactam for 10 days. After a single dose of ceftolozane alone, the ranges of mean values for half-life (2.48 to 2.64 h), the total clearance (4.35 to 6.01 liters/h), and the volume of distribution at steady state (11.0 to 14.1 liters) were consistent across dose levels and similar to those observed when ceftolozane was coadministered with tazobactam. Mean values after multiple doses for ceftolozane alone and ceftolozane-tazobactam were similar to those seen following a single dose. The pharmacokinetics of the dosing regimens evaluated were dose proportional and linear. Ceftolozane-tazobactam was well tolerated and systemic adverse events were uncommon. Mild infusion-related adverse events were the most commonly observed following multiple-dose administration. Adverse events were not dose related, and no dose-limiting toxicity was identified.

Pharmacokinetics and safety of CXA-101, a new antipseudomonal cephalosporin, in healthy adult male and female subjects receiving single- and multiple-dose intravenous infusions.

CXA-101 is a novel, broad-spectrum cephalosporin with excellent antipseudomonal activity. A Phase 1 study was performed to determine the safety, tolerability, and pharmacokinetics of CXA-101 after single- and multiple-dose intravenous administration over 1 h to healthy male and female subjects. In part 1 of the study, five cohorts of eight subjects each (six receiving CXA-101 and two receiving a placebo) received single ascending doses of 250, 500, 1,000, 1,500, and 2,000 mg. In part 2, cohorts 1 and 2 received 500 mg and 1,000 mg, respectively, every 8 h, and cohort 3 received 1,500 mg every 12 h; each cohort received dosing for 10 days. Standard safety and tolerability assessments were performed. Blood and urine pharmacokinetic samples were assayed by a validated bioanalytical method and analyzed using standard noncompartmental methodology. All 64 subjects completed dosing; none withdrew from the study. Drug-related systemic adverse events were infrequent and mild. Mild, non-treatment-limiting infusion site events occurred during multiple-dose administration. No clinically significant laboratory or electrocardiographic finding or dose-limiting toxicity was observed. CXA-101 exhibited dose-linear pharmacokinetics; the mean plasma half-life was approximately 2.3 h. More than 90% of the administered dose was eliminated unchanged through renal excretion. In summary, CXA-101 administered as a 1-hour infusion was generally safe and well tolerated in single doses up to 2,000 mg and in multiple doses up to 3 g daily over 10 days. The favorable safety and predictable pharmacokinetic profile of CXA-101 support its continuing clinical development for the treatment of serious bacterial infections.

Worldwide experience with the use of doripenem against extended-spectrum-beta-lactamase-producing and ciprofloxacin-resistant Enterobacteriaceae: analysis of six phase 3 clinical studies.

The worldwide increase in fluoroquinolone-resistant and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae pathogens has led to doripenem and other carbapenems assuming a greater role in the treatment of serious infections. We analyzed data from 6 phase 3 multinational doripenem clinical trials on ciprofloxacin-resistant Enterobacteriaceae isolates consisting of all genera (CIPRE) and ESBL-producing Enterobacteriaceae isolates consisting of Escherichia coli, Klebsiella spp., and Proteus spp. with ceftazidime MICs of >or=2 microg/ml (ESBLE) for prevalence by geographic region and disease type, in vitro activities of doripenem and comparator agents, and clinical or microbiologic outcomes in doripenem- and comparator-treated patients across disease types (complicated intra-abdominal infection [cIAI], complicated urinary tract infection [cUTI], and nosocomial pneumonia [NP]). Of 1,830 baseline Enterobacteriaceae isolates, 88 (4.8%) were ESBLE and 238 (13.0%) were CIPRE. The incidence of ESBLE was greatest in Europe (7.8%); that of CIPRE was higher in South America (15.9%) and Europe (14.4%). ESBLE incidence was highest in NP (12.9%) cases; that of CIPRE was higher in cUTI (18.3%) and NP (14.9%) cases. Against ESBLE and CIPRE, carbapenems appeared more active than other antibiotic classes. Among carbapenems, doripenem and meropenem were most potent. Doripenem had low MIC(90)s for CIPRE (0.5 microg/ml) and ESBLE (0.25 microg/ml). Doripenem and comparators were highly clinically effective in infections caused by Enterobacteriaceae, irrespective of their ESBL statuses. The overall cure rates were the same for doripenem (82%; 564/685) and the comparators (82%; 535/652) and similar for ESBLE (73% [16/22] versus 72% [21/29]) and CIPRE (68% [47/69] versus 52% [33/64]). These findings indicate that doripenem is an important therapeutic option for treating serious infections caused by ESBLE and CIPRE.

Efficacy and safety of intravenous infusion of doripenem versus imipenem in ventilator-associated pneumonia: a multicenter, randomized study.

OBJECTIVE: Doripenem is an investigational carbapenem with broad-spectrum activity against gram-negative and gram-positive pathogens, including multidrug-resistant strains, commonly responsible for ventilator-associated pneumonia (VAP). This large, phase III study compared doripenem with imipenem for the treatment of ventilator-associated pneumonia. DESIGN: Prospective, multicenter, parallel randomized, active-controlled, open-label study. SETTING: Intensive care units. PATIENTS: Adults (N = 531) who met clinical and radiologic criteria for ventilator-associated pneumonia. INTERVENTIONS: Patients were stratified by duration of mechanical ventilation (< 5 vs. > or = 5 days), severity of illness (Acute Physiology and Chronic Health Evaluation II score < or = 15 vs. > 15), and geographic region and then randomly assigned to doripenem 500 mg every 8 hrs via a 4-hr intravenous infusion or imipenem 500 mg every 6 hrs or 1000 mg every 8 hrs via 30- or 60-min intravenous infusions, respectively, for 7-14 days. MEASUREMENTS AND MAIN RESULTS: The primary efficacy end points were the clinical cure rates in the clinical modified intent-to-treat (cMITT) and clinically evaluable populations. Doripenem was noninferior to imipenem (lower boundary of 95% confidence interval around the difference between treatments > or = -20%). Clinical cure rates were 68.3% (doripenem) and 64.2% (imipenem) in the clinically evaluable and 59.0% (doripenem) and 57.8% (imipenem) in the cMITT populations. In patients with Pseudomonas aeruginosa, clinical cure was 80.0% (doripenem) and 42.9% (imipenem) (p not significant); microbiological cure was 65.0% (doripenem) and 37.5% (imipenem). Only 18% (5 of 28) of P. aeruginosa isolates had minimum inhibitory concentration > or = 8 microg/mL at baseline or following therapy in the doripenem arm compared with 64% (16 of 25) in the imipenem treatment group (p = .001). Clinical cure rate was higher with doripenem than imipenem at higher Acute Physiology and Chronic Health Evaluation II scores and older ages. Doripenem was generally well tolerated. CONCLUSIONS: In this large, phase III study of patients with ventilator-associated pneumonia, a 4-hr intravenous infusion of doripenem was clinically efficacious and therapeutically noninferior to imipenem.

Efficacy and tolerability of IV doripenem versus meropenem in adults with complicated intra-abdominal infection: a phase III, prospective, multicenter, randomized, double-blind, noninferiority study.

BACKGROUND: Complicated intra-abdominal infections (cIAIs) require surgical intervention and empiric antibacterial therapy. Doripenem, a broad-spectrum carbapenem, provides coverage of key gram-negative and -positive aerobes and anaerobes encountered in cIAI. OBJECTIVE: This study was designed to compare the efficacy and safety profile of doripenem and meropenem in hospitalized adult patients with cIAI. METHODS: In this prospective, multicenter, doubleblind, noninferiority study, hospitalized adults with cIAI were randomly assigned to receive doripenem 500 mg IV q8h or meropenem 1 g IV q8h. After a minimum of 9 doses and adequate clinical improvement (relative to before the start of IV study drug, decreased body temperature and white blood cell count, improved or absent signs and symptoms of cIAI, and return of normal bowel function), patients could be switched to oral amoxicillin/clavulanate. Antibacterial therapy (IV plus subsequent oral) was given for a total of 5 to 14 days. The coprimary efficacy end points were the clinical cure rate (complete resolution or significant improvement of signs or symptoms of the index infection) in patients microbiologically evaluable (>or=1 baseline pathogen isolated from an intra-abdominal culture that was susceptible to both IV study drug therapies) at the test-of-cure (TOC) visit (21-60 days after the completion of study drug therapy) and the clinical cure rate in the microbiological modified intent-to-treat (mMITT) population (a bacterial pathogen identified at baseline, regardless of its susceptibility to the study drug). Noninferiority was concluded if the lower limit of the 2-sided 95% CI for the difference (doripenem minus meropenem) in the proportion of patients classified as clinical cures was >or=-15%. RESULTS: A total of 476 patients were enrolled. The microbiologically evaluable population (319 patients) was 62.7% male and 67.7% white, with a mean age and weight of 46.7 years and 77.2 kg, respectively. In this population, doripenem and meropenem were associated with clinical cure rates at the TOC visit of 85.9% and 85.3%, respectively. The corresponding treatment difference was 0.6% (95% CI, -7.7% to 9.0%); this difference was not statistically significant. Similarly, in the mMITT population (385 patients), the clinical cure rates were 77.9% and 78.9%, respectively, and the corresponding 1.0% treatment difference was not statistically significant (95% CI, -9.7% to 7.7%). Clinical cure rates were not significantly different between the 2 treatment arms in key subgroups (eg, age, sex, race, baseline Acute Physiology and Chronic Health Evaluation II score, primary infection site). Microbiological eradication rates for common pathogens isolated at study entry were not significantly different between the 2 treatment groups. Doripenem was well tolerated in the population studied. In the intent-to-treat population (471 patients), 83.0% and 78.0% of patients experienced >or=1 adverse event (AE) and 13.2% and 14.0% experienced >or=1 serious AE in the doripenem and meropenem treatment arms, respectively. In the doripenem and meropenem treatment arms, AEs resulted in study drug discontinuation in 5.1% and 2.1% of patients and death in 2.1% and 3.0% of patients, respectively. CONCLUSIONS: The present study found that doripenem (500 mg q8h) was effective in the treatment of cIAI, was therapeutically noninferior to meropenem (1 g q8h), with a safety profile not significantly different from that of meropenem in this selected population of patients with cIAI.

Hospital resource utilization with doripenem versus imipenem in the treatment of ventilator-associated pneumonia.

BACKGROUND: Ventilator-associated pneumonia (VAP) is a common nosocomial infection that is associated with prolonged length of stay (LOS) and significant mortality. OBJECTIVE: The aim of this study was to compare resource utilization with doripenem, an investigational carbapenem, versus imipenem from a hospital perspective among patients with VAP. METHODS: This analysis was based on data from a Phase III, randomized, open-label, noninferiority study that compared clinical cure of VAP with doripenem 500 mg q8h i.v. (4-hour infusion) with imipenem 500 mg q6h (30-minute infusion) or 1000 mg q8h i.v. (1-hour infusion). Total hospital LOS, intensive care unit (ICU) LOS, and time on mechanical ventilation for doripenem and imipenem were compared in a clinical modified intent-to-treat population. P values were determined using the generalized Wilcoxon test, which compared treatments in a time-to-event analysis, censoring patients at the late follow-up visit (28-35 days after the end of i.v. therapy). RESULTS: Patients in the doripenem and imipenem groups had similar baseline clinical characteristics. Median hospital LOS was significantly shorter with doripenem versus imipenem (22 vs 27 days; P=0.010); median time on mechanical ventilation was significantly shorter for doripenem (7 vs 10 days; P=0.034); median ICU LOSs were similar between the 2 groups (12 vs 13 days). Clinical cure and mortality rates were similar. CONCLUSIONS: Of the 3 primary end points in this analysis, hospital LOS and time on mechanical ventilation were significantly shorter with doripenem compared with imipenem; no statistical significance was observed in ICU LOS. These findings suggest that doripenem use may be associated with an economic and clinical benefit to patients and hospitals.

Bowel colonization with vancomycin-resistant enterococci after antimicrobial therapy for intra-abdominal infections: observations from 2 randomized comparative clinical trials of ertapenem therapy.

The impact of different antimicrobial regimens for intra-abdominal infections on the frequency of bowel colonization with vancomycin-resistant enterococci (VRE) was examined in 2 randomized open-label trials of intra-abdominal infection comparing piperacillin-tazobactam or ceftriaxone/metronidazole with ertapenem. In these short-term studies, overall rates of bowel colonization with VRE were generally comparable after treatment with piperacillin-tazobactam, ceftriaxone/metronidazole, or ertapenem.

In vitro susceptibilities of aerobic and facultative gram-negative bacilli isolated from patients with intra-abdominal infections worldwide: the 2002 Study for Monitoring Antimicrobial Resistance Trends (SMART).

BACKGROUND: The Study for Monitoring Antimicrobial Resistance Trends (SMART) was begun in 2002 to monitor international drug-resistance patterns among aerobic and facultative gram-negative bacilli isolated from patients with intra-abdominal infections. METHODS: In 2002, 40 medical centers from 17 countries collected consecutive non-duplicate isolates from intra-abdominal infections for susceptibility testing against 12 antimicrobial agents using the broth microdilution methods recommended by the Clinical and Laboratory Standards Institute (formerly the National Committee for Clinical Laboratory Standards). RESULTS: A total of 3,134 aerobic and facultative gram-negative bacilli were isolated. Enterobacteriaceae accounted for 82% of the total and were most consistently susceptible to amikacin and the carbapenems. Escherichia coli (45%) and Klebsiella spp. (17%) were the most common species. The susceptibility rates of these organisms to the 12 antimicrobial agents differed among geographic regions, with isolates from the Asia/Pacific and Latin American regions usually having the highest rates of resistance. Ampicillin/sulbactam was the agent least frequently active against E. coli (56% susceptible) and Klebsiella spp. (73% susceptible). Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically in 7% of E. coli, 13% of Klebsiella spp., and 18% of Enterobacter spp. Producers of ESBL overall had a more antibiotic-resistant profile than non-producers but were usually susceptible to carbapenems. CONCLUSIONS: Antimicrobial resistance rates among gram-negative bacilli isolated from intra-abdominal infections differed among geographic regions. The carbapenems were consistently active in vitro against Enterobacteriaceae worldwide, including ESBL producers.

A study evaluating the efficacy, safety, and tolerability of ertapenem versus ceftriaxone for the treatment of community-acquired pneumonia in adults.

In a double-blind, multicenter trial, 502 patients hospitalized with community-acquired pneumonia were randomized to receive therapy with either ertapenem or ceftriaxone (for each, 1 g given intravenously once daily). After a minimum of 3 days, therapy could be switched to oral amoxicillin-clavulanate. The median duration of intravenously administered therapy for the 383 clinically evaluable patients was 4 days for both treatment groups; 345 patients (90.1%) had their treatment switched to orally administered therapy. Of the clinically evaluable patients, 168 (92.3%) in the ertapenem group and 183 (91.0%) in the ceftriaxone group had a favorable clinical response. Streptococcus pneumoniae was the most commonly isolated pathogen, and high cure rates were observed both for penicillin-susceptible and -nonsusceptible infections in the ertapenem group (28 [87.5%] of 32 patients versus 17 [100%] of 17 patients, respectively). Both treatment regimens were generally well tolerated; the most common drug-related adverse events reported were diarrhea (2.9% versus 2.7%) and nausea (0.8% versus 2.0%) in the ertapenem and ceftriaxone groups, respectively. These results suggest that ertapenem and ceftriaxone therapy have similar efficacy and safety in hospitalized patients with community-acquired pneumonia.

Resistance in Enterobacteriaceae: results of a multicenter surveillance study, 1995-2000.

OBJECTIVES: To assess changes over time in susceptibility of Enterobacteriaceae from patients in ICUs, compare susceptibility rates of isolates from patients in ICUs with those from inpatients outside ICUs, and explore phenotypic patterns of cross-resistance and co-resistance. DESIGN: From 1995 to 2000, centers participating in the ICU Surveillance Study tested 100 to 200 consecutive nosocomial gram-negative bacilli by broth microdilution. SETTING: Each year, 42 to 97 U.S. hospitals tested isolates. RESULTS: In all years, imipenem was the most potent agent tested, followed by amikacin and ertapenem. Extended-spectrum beta-lactam and monobactam agents had good activity against Escherichia coli and Klebsiella species, but limited activity against Enterobacter species. Susceptibility to imipenem and amikacin did not fluctuate during the analysis period, whereas susceptibility to ceftazidime, ceftriaxone, and ciprofloxacin decreased 2% to 5%. The decline was most pronounced for susceptibility of Escherichia coli to ciprofloxacin: 98.7% of ICU isolates were susceptible in 1995 versus 93.2% in 2000. Susceptibility of ICU isolates was lower than that of non-ICU isolates, except for ciprofloxacin, for which the reverse was true. Cross-resistance was common among extended-spectrum cephalosporins and penicillins, but uncommon between imipenem and ertapenem. Only imipenem and ertapenem remained highly active against Enterobacteriaceae with a phenotype suggesting possible production of an extended-spectrum beta-lactamase and those with a phenotype suggesting possible Amp C hyperproduction. CONCLUSIONS: Imipenem was the most active agent against nosocomial Enterobacteriaceae. Susceptibility to ciprofloxacin decreased from 1995 to 2000, particularly in Escherichia coli, and, in contrast to other agents, was lower among non-ICU isolates.

Ertapenem therapy for community-acquired pneumonia in the elderly.

OBJECTIVES: To compare the efficacy and safety of ertapenem, 1 g once a day, with ceftriaxone, 1 g once a day, for treatment of the subgroup of patients aged 65 and older with community-acquired pneumonia (CAP) requiring parenteral therapy. DESIGN: Combined data from patients aged 65 and older in two randomized, double-blind clinical trials. SETTING: Eighty international centers. PARTICIPANTS: Eight hundred fifty-seven treated patients, of whom 351 were aged 65 and older. INTERVENTIONS: Intravenous or intramuscular ertapenem or ceftriaxone with the option to switch to oral amoxicillin-clavulanate after at least 3 days of parenteral therapy. MEASUREMENTS: Clinical efficacy was assessed at completion of parenteral therapy and 7 to 14 days after all therapy had been completed (test of cure (TOC) assessment). Bacterial eradication was assessed at the TOC visit. Safety was assessed daily during study therapy and for 14 days thereafter. RESULTS: One hundred forty-eight clinically evaluable patients aged 65 and older were treated with ertapenem and 125 with ceftriaxone. Pathogens were identified in 157 (57.5%) patients (the most common being Streptococcus pneumoniae), most of which were penicillin-susceptible. Clinical cure rates were 95.9% for patients in the ertapenem group and 92.7% for patients in the ceftriaxone group at completion of parenteral therapy and 93.9% and 90.4%, respectively, at the TOC assessment. Overall bacterial eradication rates were 92.8% (77 of 83) for patients treated with ertapenem and 93.2% (69 of 74) for those treated with ceftriaxone. The most common drug-related adverse experiences in both treatment groups were diarrhea and mild to moderate elevation of serum aminotransferase levels. CONCLUSION: Ertapenem 1 g once a day was highly effective for treatment of elderly patients with CAP requiring parenteral therapy and was as effective as ceftriaxone. Ertapenem was generally well tolerated, with an overall safety profile similar to ceftriaxone.

Phenotypic antimicrobial resistance patterns in Pseudomonas aeruginosa and Acinetobacter: results of a Multicenter Intensive Care Unit Surveillance Study, 1995-2000.

Susceptibility data from the Intensive Care Unit (ICU) Surveillance Study for 10,361 isolates of Pseudomonas aeruginosa and 2,573 isolates of Acinetobacter tested at centers in the United States during 1995 to 2000 were analyzed. In all years, amikacin was the most active antimicrobial agent against P. aeruginosa, and imipenem was the most active agent against Acinetobacter. Resistance of both organisms to common therapeutic agents tested throughout the analysis period increased from 1995 to 2000, although the increase was not consistent for all drugs from year to year. The increases were higher among Acinetobacter, and for both organisms, the increase in resistance was greatest for ciprofloxacin. Among all P. aeruginosa tested in 1999 and 2000, resistance to ciprofloxacin was 9-11% higher for isolates from patients on general hospital wards than those from ICUs. Of the 3424 ICU isolates of P. aeruginosa tested in 1999 and 2000, 77 (2.2%) were multidrug-resistant (i.e., resistant to piperacillin, ceftazidime, imipenem, and gentamicin). Twenty (3.9%) isolates of Acinetobacter in 1999 and seven (1.9%) in 2000 were resistant to imipenem, ceftazidime, piperacillin-tazobactam, ciprofloxacin, and amikacin. Although resistance in both P. aeruginosa and Acinetobacter increased, multidrug-resistant (to > or =4 agents) strains were uncommon.

Use of surrogate antimicrobial agents to predict susceptibility to ertapenem.

Broth or agar dilution susceptibility test results for Enterobacteriaceae (11,775 strains), anaerobes (2888 strains), staphylococci (2206 strains), Haemophilus spp. (840 strains), group A streptococci (280 strains), group B streptococci (269 strains), Streptococcus pneumoniae (709 strains), and 160 other streptococci were analyzed to identify surrogate antimicrobial agents to predict susceptibility to ertapenem. Ertapenem MIC interpretive categories approved by the United States FDA were compared to those of imipenem, oxacillin (staphylococci), or penicillin (streptococci). Ertapenem resistance was rare (1.2%) among 8187 consecutively collected clinical isolates of Enterobacteriaceae, including a large proportion of isolates from intensive care units. Absolute categorical agreement between ertapenem and imipenem, and very major (false susceptible) and major errors (false resistant) using imipenem to predict ertapenem results were 97.2%, 0.9%, and 0.4%, respectively, for Enterobacteriaceae (10,992 strains tested against both drugs) and 99.0%, 0.2%, and 0% for anaerobes. All Haemophilus spp., groups A and B streptococci, penicillin-susceptible and -intermediate S. pneumoniae, and other penicillin-susceptible streptococci were susceptible to ertapenem. All oxacillin-susceptible Staphylococcus aureus were ertapenem susceptible, except 1 that was intermediate. Surrogate antimicrobial agents that can be used to reliably predict ertapenem susceptibility by MIC tests are imipenem for Enterobacteriaceae and anaerobes, oxacillin for staphylococci, and penicillin for streptococci.

Safety and local tolerability of intramuscularly administered ertapenem diluted in lidocaine: a prospective, randomized, double-blind study versus intramuscular ceftriaxone.

BACKGROUND: Ertapenem is a new, structurally unique, parenteral beta-lactam antimicrobial agent that can be administered once daily. OBJECTIVE: This study compared the local tolerability of ertapenem 1 g once a day administered intramuscularly (IM) versus IM ceftriaxone, with both drugs reconstituted in lidocaine. METHODS: In this prospective, double-blind, multicenter study, adult patients with lower respiratory tract infection, skin infection, or urinary tract infection requiring initial parenteral therapy were randomly assigned in a 3:1 ratio to treatment with IM ertapenem 1 g once daily or IM ceftriaxone 1 g once daily. Although study drugs were administered by unmasked personnel, the patients, investigators, and the sponsor medical reviewer were blinded. Patients who improved clinically could be switched to oral amoxicillin-clavulanate after at least 2 days of IM therapy. Tolerability and safety analyses were carried out for the treated population, and efficacy analyses were performed for the modified intent-to-treat population. RESULTS: A total of 117 patients were randomized. The 87 patients in the ertapenem group and 30 in the ceftriaxone group received IM therapy for a mean duration of 4.1 and 3.8 days, respectively. During treatment, 35.6% (31/87) of patients treated with ertapenem and 43.3% (13/30) of those treated with ceftriaxone experienced > or =1 symptom at the local injection site; the most common symptom was tenderness, followed by pain. Symptoms were moderate to severe in only 1 patient (1.1%) in the ertapenem group and 3 patients (10.0%) in the ceftriaxone group. Clinical drug-related adverse events were reported during IM therapy in 14 patients (16.1%) in the ertapenem group and 5 patients (16.7%) in the ceftriaxone group. Mean +/- SD creatine kinase concentrations, measured in all patients, were 204.8+/-234.8 U/L at the end of IM ertapenem therapy and 382.9+/-721.1 U/L at the end of IM ceftriaxone therapy; at follow-up, values had returned to normal or had decreased in all cases. CONCLUSIONS: Ertapenem 1 g (reconstituted in lidocaine) administered once daily IM was generally well tolerated. The tolerability and safety profiles of IM ertapenem therapy in this study were comparable to those of IM ceftriaxone therapy.

A comprehensive regulatory framework to address the unmet need for new antibacterial treatments.

To bring new antibacterial drugs to the market is challenging because discovery of new agents is difficult, two large trials per indication are needed in accordance with traditional regulatory requirements, and the economic reward is limited if the use of new antibiotics is constrained. These challenges have resulted in an alarmingly thin antibiotic pipeline, despite the rapid and continued growth in the need for new drugs. Approaches that balance the quantity of data needed for registration with the unmet medical need would encourage work in this area. Therefore, a tiered regulatory framework that allows either disease-based or pathogen-based label indications is proposed, with label wording that promotes the most appropriate use of new agents. Such a framework is within the bounds of present regulatory approaches, is amenable to international harmonisation, and would be a welcome step towards the facilitation of a robust and sustainable discovery and development infrastructure.