Efficacy and safety of tigecycline monotherapy compared with vancomycin plus aztreonam in patients with complicated skin and skin structure infections: Results from a phase 3, randomized, double-blind trial

Tigecycline and Hypoglycemia, When and How?

Objective: To describe the clinical characteristics of hypoglycemia that develop with tigecycline therapy and to review and summarize the current evidence of this uncommonly occurring metabolic adverse effect of tigecycline therapy. Underlying risk factors and potential mechanisms are also discussed. Data source: A 3-phase literature search was performed. In phase 1, the Cochrane Central Register of Controlled Trials (CENTRAL) Library, MEDLINE, and Embase electronic databases were searched for hypoglycemia and tigecycline, published from inception until August 2023. In phase 2, MEDLINE was searched for tigecycline randomized controlled trials and results were manually screened for hypoglycemia. In phase 3, the US Food and Drug Administration Adverse Event Reporting System public dashboard was searched for reports on tigecycline and hypoglycemia from June 2005 until July 2023. Study selection and data extraction: Relevant English-language citations and those conducted in humans were considered. Relevance to patient care and clinical practice: Hypoglycemia of various causes is an independent mortality risk. This review raises awareness among clinicians about the possibility of hypoglycemia with tigecycline therapy. Conclusion: Data on tigecycline-related hypoglycemia are scarce. Hypoglycemia may occur at any time during tigecycline therapy and can be severe and persist for days after tigecycline cessation. Renal dysfunction or renal replacement therapy may predispose to severe hypoglycemia during tigecycline therapy. Tigecycline-related hypoglycemia may develop in patients with or without diabetes mellitus and appears independent of insulin or antidiabetic agents. Intravenous dextrose showed efficacy in the restoration of euglycemia. Studies are needed to determine whether tigecycline-related hypoglycemia is iatrogenic or spontaneous.

Re-establishing the utility of tetracycline-class antibiotics for current challenges with antibiotic resistance

The progressive increase in antibiotic resistance in recent decades calls for urgent development of new antibiotics and antibiotic stewardship programs to help select appropriate treatments with the goal of minimising further emergence of resistance and to optimise clinical outcomes. Three new tetracycline-class antibiotics, eravacycline, omadacycline, and tigecycline, have been approved within the past 15 years, and represent a new era in the use of tetracyclines. These drugs overcome the two main mechanisms of acquired tetracycline-class resistance and exhibit a broad spectrum of in vitro activity against gram-positive, gram-negative, anaerobic, and atypical pathogens, including many drug-resistant strains. We provide an overview of the three generations of tetracycline-class drugs, focussing on the efficacy, safety, and clinical utility of these three new third-generation tetracycline-class drugs. We also consider various scenarios of unmet clinical needs where patients might benefit from re-engagement with tetracycline-class antibiotics including outpatient treatment options, patients with known β-lactam antibiotic allergy, reducing the risk of Clostridioides difficile infection, and their potential as monotherapy in polymicrobial infections while minimising the risk of any potential drug-drug interaction. KEY MESSAGESThe long-standing safety profile and broad spectrum of activity of tetracycline-class antibiotics made them a popular choice for treatment of various bacterial infections; unfortunately, antimicrobial resistance has limited the utility of the early-generation tetracycline agents.The latest generation of tetracycline-class antibiotics, including eravacycline, tigecycline, and omadacycline, overcomes the most common acquired tetracycline resistance mechanisms.Based on in vitro characteristics and clinical data, these newer tetracycline agents provide an effective antibiotic option in the treatment of approved indications in patients with unmet clinical needs - including patients with severe penicillin allergy, with renal or hepatic insufficiency, recent Clostridioides difficile infection, or polymicrobial infections, and those at risk of drug-drug interactions.

Efficacy and safety of optional parenteral antimicrobial therapy for complicated skin and soft tissue infections: A systematic review and Bayesian network meta-analysis

BACKGROUND

Skin and soft tissue infections (SSTIs) carry significant economic burden, as well as morbidity and mortality, especially when caused by methicillin-resistant Staphylococcus aureus. This study aims to investigate the efficacy and safety of optional antimicrobial therapy for the treatment of complicated SSTIs (cSSTIs).

METHODS

We searched PubMed, Medline (Via Ovid SP), Embase (Via Ovid SP), and the Cochrane Central Register of Controlled Trials from their inception to March 22, 2021 for randomized controlled trials (RCTs) that studied the use of optional antimicrobial therapy for cSSTIs. Citations' screening, study selection, data extraction, and risk of bias assessment were independently performed by 2 authors. The primary outcomes were clinical and microbiological treatment success, and adverse events (AEs) were also assessed.

RESULTS

A total of 48 trials covering 24,381 patients assessing 20 types of antimicrobial treatment modalities were included. Overall, omadacycline was associated with the highest beneficial effect on clinical and microbiological treatment success and with the largest rank probability based on surface under the cumulative ranking curve values, avarofloxacin was closely followed. Both had, however, omadacycline was related to moderately safety profiles. Lefamulin ranked as the best option was associated with the lowest risk of severe AEs. Subgroup analysis showed similar results. The quality of primary outcomes was moderate to low.

CONCLUSIONS

The use of omadacycline was associated with higher rates of clinical and microbiological treatment success for the treatment of cSSTIs, with a relative low risk of AEs. Due to the limitations of the included RCTs, high-quality and well-designed RCTs are needed to further confirm the results.

Tigecycline-Associated Coagulopathy: A Single-Center Retrospective Analysis

INTRODUCTION

The purpose of this study was to assess clinical characteristics and risk factors for tigecycline-associated prothrombin time (PT) and activated partial thromboplastin time (aPTT) prolongation.

METHODS

We performed a retrospective analysis on coagulation parameters before and during tigecycline treatment in 55 patients in our hospital with severe infections, mainly pneumonia caused by Acinetobacter baumannii. Patients were divided into different groups according to prolongation of PT and aPTT, and clinical features involved were explored. Univariate and multivariable binary logistic regression analyses were used to identify risk factors for tigecycline-associated PT and aPTT increase.

RESULTS

We found that PT values increased from 12.73 ± 1.87 to 13.86 ± 2.06 during the treatment compared with premedication (p < 0.001), and the aPTT level prolonged significantly from 33.63 ± 11.24 to 38.15 ± 11.81 (p < 0.001). The multivariate analyses identified 2 variables that were associated with tigecycline-induced PT prolongation: albumin level (p = 0.018) and weight-adjusted tigecycline dosage (p = 0.005). In addition, treatment duration was the only risk factor for tigecycline-induced aPTT prolongation (p = 0.043).

CONCLUSION

Albumin level, weight-adjusted tigecycline dosage, treatment duration may serve as risk indicators for tigecycline-associated coagulation dysfunction. Physicians should be careful with coagulation disorder when prescribing tigecycline in clinical practice, especially in patients with risk factors.

Diagnosis and management of infections caused by multidrug-resistant bacteria: guideline endorsed by the Italian Society of Infection and Tropical Diseases (SIMIT), the Italian Society of Anti-Infective Therapy (SITA), the Italian Group for Antimicrobial Stewardship (GISA), the Italian Association of Clinical Microbiologists (AMCLI) and the Italian Society of Microbiology (SIM)

Management of patients with infections caused by multidrug-resistant organisms is challenging and requires a multidisciplinary approach to achieve successful clinical outcomes. The aim of this paper is to provide recommendations for the diagnosis and optimal management of these infections, with a focus on targeted antibiotic therapy. The document was produced by a panel of experts nominated by the five endorsing Italian societies, namely the Italian Association of Clinical Microbiologists (AMCLI), the Italian Group for Antimicrobial Stewardship (GISA), the Italian Society of Microbiology (SIM), the Italian Society of Infectious and Tropical Diseases (SIMIT) and the Italian Society of Anti-Infective Therapy (SITA). Population, Intervention, Comparison and Outcomes (PICO) questions about microbiological diagnosis, pharmacological strategies and targeted antibiotic therapy were addressed for the following pathogens: carbapenem-resistant Enterobacterales; carbapenem-resistant Pseudomonas aeruginosa; carbapenem-resistant Acinetobacter baumannii; and methicillin-resistant Staphylococcus aureus. A systematic review of the literature published from January 2011 to November 2020 was guided by the PICO strategy. As data from randomised controlled trials (RCTs) were expected to be limited, observational studies were also reviewed. The certainty of evidence was classified using the GRADE approach. Recommendations were classified as strong or conditional. Detailed recommendations were formulated for each pathogen. The majority of available RCTs have serious risk of bias, and many observational studies have several limitations, including small sample size, retrospective design and presence of confounders. Thus, some recommendations are based on low or very-low certainty of evidence. Importantly, these recommendations should be continually updated to reflect emerging evidence from clinical studies and real-world experience.

A pharmacovigilance study of the association between tetracyclines and hepatotoxicity based on Food and Drug Administration adverse event reporting system data

Background While tetracycline antibiotics are commonly prescribed in practice, the risk of drug-induced liver injury (DILI) remains controversial. Aim To evaluate the association of DILI with tetracycline antibiotics. Method All DILI cases of tetracycline antibiotics as primary suspected drugs were extracted from the US Food and Drug Administration adverse event reporting system (FAERS). The outcomes included severe DILI, hepatocellular injury, cholestatic injury, and liver failure. Disproportionality analyses were conducted by estimating the reporting odds ratio (ROR) and the information component (IC). Results A total of 1,435 liver injury cases associated with tetracycline antibiotics were identified. The DILI signal was detected in tigecycline, minocycline, and doxycycline. The RORs and the 95% confidence intervals (95% CI) of tigecycline, minocycline, and doxycycline were (ROR 5.85, 95% CI 4.96-6.91), (ROR 6.4, 95% CI 5.76-7.11), and (ROR 2.07, 95% CI 1.86-2.31), respectively. Compared to minocycline (ROR 5.5, 95% CI 4.94-6.12; IC 2.35, 95% CI 1.98-2.68) and doxycycline (ROR 1.91, 95% CI 1.71-2.12; IC 0.91, 95% CI 0.55-1.26), tigecycline showed a stronger association with hepatocellular injury (ROR 7.11, 95% CI 6.13-8.23; IC 2.68, 95% CI 2.16-3.13). Tigecycline also showed a stronger association with cholestatic injury (ROR 12.16, 95% CI 10.13-14.61; IC 3.51, 95% CI 2.79-4) than minocycline (ROR 3.23, 95% CI 2.59-4.04; IC 1.67, 95% CI 0.9-2.37) or doxycycline (ROR 2.86, 95% CI 2.47-3.31; IC 1.5, 95% CI 1-1.97). Tigecycline (ROR 6.56, 95% CI 4.57-9.41; IC 2.69, 95% CI 1.28-3.64) and minocycline (ROR 4.22, 95% CI 3.14-5.66; IC 2.06, 95% CI 1-2.93) showed a significant association with liver failure. Conclusion The data mining of FAERS suggested an association between DILI and tigecycline, minocycline, and doxycycline.

Efficacy of Tigecycline as Salvage Therapy in Multidrug-Resistant Febrile Neutropenia in Patients with Acute Leukemia—A Single Center Analysis

Severe infectious complications remain the main cause of mortality in leukemia patients due to a long period of profound neutropenia. Standardized regimens for antimicrobial, antifungal, and antiviral prophylaxis and therapy in neutropenic patients have improved infection-associated mortality. Nevertheless, many patients are refractory to these multidrug approaches. Tigecycline is a last-resort antibiotic with a broad-spectrum activity; unfortunately, clinical experience in multidrug-resistant febrile neutropenia is limited. The aim was to evaluate the efficacy of tigecycline treatment in comparison to standard treatment in this patient cohort. In this single center analysis, we analyzed the clinical courses of 73 patients with acute leukemia and diagnosis of febrile neutropenia resistant to hospital-based multidrug escalation levels who continued on a standard approach without antibiotics as the last resort (n = 30) or were switched to tigecycline in addition to carbapenem treatment (n = 43). We observed comparable overall response rates (decrease in C-reactive protein or resolution of fever) in both patient cohorts. Switching the antibiotic approach to tigecycline showed lower absolute sepsis (33% vs. 47%, p = 0.235) and infection-associated mortality rates (5% vs. 13%, p = 0.221). Prospective larger randomized studies are necessary to underline these results and to be able to generate reliable statistics.

Efficacy and safety of delafloxacin, ceftaroline, ceftobiprole, and tigecycline for the empiric treatment of acute bacterial skin and skin structure infections: A network meta-analysis of randomized controlled trials

Background

Method

Results

Conclusion

Real-World Data of Tigecycline-Associated Drug-Induced Liver Injury Among Patients in China: A 3-year Retrospective Study as Assessed by the Updated RUCAM

Background: Tigecycline, a glycylcycline antibiotic, is increasingly used clinically for the treatment of severe infections caused by multidrug-resistant bacteria, but it is also associated with hepatotoxicity. However, the incidence and risk factors of tigecycline-associated drug-induced liver injury (DILI) are unclear. We conducted this study to investigate the incidence, characteristics and risk factors of tigecycline-associated DILI in the real-world clinic setting. Patients and Methods: A retrospective analysis was conducted in inpatients who received tigecycline treatment from January 2018 to January 2020. Based on the biochemical criteria of DILI and the causality assessment by Roussel Uclaf Causality Assessment Method (RUCAM) using cases with a probable or highly probable causality grading, two clinical pharmacists and one clinician worked together to screen patients for tigecycline-associated DILI. Then patients with DILI were randomly matched by gender in a ratio of 1:2 to the remaining patients in the tigecycline cohort without biochemical abnormalities to identify risk factors. Results: A total of 973 patients from 1,250 initial participants were included. The incidence of tigecycline-associated DILI was 5.7% (55/973). Among 55 DILI patients, 10 cases presented with the hepatocellular pattern, 4 cases belonged to the mixed pattern, and 41 presented with the cholestatic pattern. Most cases reached the severity of grade 1 and 2. The rate of recovery in hepatocellular pattern, mixed pattern, and cholestatic pattern was 70.0, 50.0, and 41.5%, respectively. The proportion of the DILI cases treated with high dose (100 mg) and prolonged duration (>14 days) was significantly higher than standard dose and routine duration (100.0% vs. 18.1%, p < 0.05). Logistic regression analysis showed that high maintenance dose (OR = 1.028, p = 0.002), prolonged duration (OR = 1.208, p = 0.000), and number of hepatotoxic drugs (OR = 2.232, p = 0.000) were independent factors of tigecycline-associated DILI. Conclusion: Tigecycline was associated with liver injury, with a slightly higher incidence (5.7%) than the frequency of "frequent" (5%) defined by the Medical Dictionary for Regulatory Activities. Patients with a high maintenance dose and prolonged tigecycline regimen, as well as concomitant use of multiple hepatotoxic drugs should be paid more attention.

Safety considerations with new antibacterial approaches for chronic bacterial prostatitis

Introduction: Chronic bacterial prostatitis (CBP) is a difficult-to-eradicate infection. Antibacterial therapy with currently licensed agents is hindered due to the increasing emergence of pathogen resistance worldwide and to frequent infection relapse. With limited treatment options, physicians are investigating new agents, which, however, may raise safety concerns.Areas covered: Antibacterial agents currently licensed for CBP were not considered. Available reports about the safety and efficacy of antibacterial agents that have been clinically tested or tentatively used to treat CBP in single cases were evaluated. This review also focused on agents targeting Gram-positive pathogens, whose prevalence as causative agents of CBP is increasing.Expert opinion: (i) Most antibacterial agents considered in this review have been administered off-label in the interest of patients, and their use requires particular caution. (ii) Reports describing the usage of many of the drugs reviewed here are still scant, and readers should be warned of the limited published evidence supporting therapy for CBP with these agents. (iii) As treatment must extend over several weeks, medium-term adverse events may occur and therapy should be individualized, taking into account the dosage and the potential toxicity of each specific antibiotic. Regarding dangerous drug-drug interactions, particular attention should be paid to the risk of ECG-QT-interval elongation.

Staphylococcal Skin and Soft Tissue Infections

Staphylococcus aureus is the most common bacteria causing purulent skin and soft tissue infections. Many disease-causing S aureus strains are methicillin resistant; thus, empiric therapy should be given to cover methicillin-resistant S aureus. Bacterial wound cultures are important for characterizing local susceptibility patterns. Definitive antibiotic therapy is warranted, although there are no compelling data demonstrating superiority of any one antibiotic over another. Antibiotic choice is predicated by the infection severity, local susceptibility patterns, and drug-related safety, tolerability, and cost. Response to therapy is expected within the first days; 5 to 7 days of therapy is typically adequate to achieve cure.

Current Treatment Options for Acute Skin and Skin-structure Infections

Acute bacterial skin and skin-structure infections (ABSSSIs) are a common reason for seeking care at acute healthcare facilities, including emergency departments. Staphylococcus aureus is the most common organism associated with these infections, and the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) has represented a considerable challenge in their treatment. To address this need, a number of new antibiotics have been developed for the treatment of ABSSSIs in the past several years. Most of these agents focus primarily on gram-positive organisms, particularly MRSA; however, there has not been an oral agent that can reliably treat MRSA, as well as relevant gram-negative pathogens. Acute skin infections that involve mixed gram-positive and gram-negative pathogens must also be considered as they can be associated with discordant antimicrobial therapy. Here, I review ABSSSI treatment guidelines in the hospital setting and discuss current and future antibiotic options for treatment of this commonly encountered infection.

Tigecycline versus INR increase; more than expected?

Objectives: The aim of the study was to investigate the frequency of tigecycline-associated INR abnormality.Methods: Patients who were hospitalized between June and September 2016 and treated with tigecycline including therapy were extracted from hospital database and retrospectively reviewed. INR values at the beginning and end of treatment were compared.Results: A total of 79 patients who received tigecycline were identified by analyzing the hospital database. Nineteen patients were excluded from the study since INR was not measured at the beginning and/or end of treatment. In 55 of the 60 patients, INR levels were within normal limits (0.9-1.2) at the beginning of treatment while 19 of these 55 (34,5%) had prolonged INR after treatment. Prolongation was found to be mild (1.01-1.25 x ULN-upper limit of normal) in 12 of 19 patients, moderate (1.26-1.5 x ULN) in six and severe (1.51-3.0 x ULN) in one. In 10 of 19 patients, tigecycline was stopped, and the INR values normalized. There was no difference in INR abnormality rate between tigecycline monotherapy versus combination therapy receiving cases (19/27-33% vs. 10/33-30% p:1).Conclusion: These data show that INR prolongation may develop as common as 34.6% during tigecycline therapy. Regular INR follow-up may be beneficial in cases receiving tigecycline.

Busting the Myth of "Static vs Cidal": A Systemic Literature Review

We sought to determine if clinical data validate the dogma that bactericidal antibiotics are more clinically effective than bacteriostatic agents. We performed a systematic literature review of published, randomized, controlled trials (RCTs) that compared a bacteriostatic agent to a bactericidal agent in the treatment of clinical, bacterial infections. Of 56 identified trials published since 1985, 49 found no significant difference in efficacy between bacteriostatic and bactericidal agents. In 6 trials it was found that the bacteriostatic agent was superior to the bactericidal agent in efficacy. Only 1 trial found that the bactericidal agent was superior; in that case, the inferiority of the static agent was explainable by underdosing of the drug based on pharmacokinetic-pharmacodynamic analysis. Thus, virtually all available data from high-quality, RCTs demonstrate no intrinsic superiority of bactericidal compared to bacteriostatic agents. Other drug characteristics such as optimal dosing, pharmacokinetics, and tissue penetration may be more important efficacy drivers.

Influence of age on the clinical efficacy of tigecycline in severely ill patients

OBJECTIVES

The aim of this study was to define the relationship between age and response to tigecycline among patients treated for complicated skin and soft-tissue infections (cSSTIs) and complicated intra-abdominal infections (cIAIs).

METHODS

Pooled data derived from five European observational studies on the use of tigecycline (July 2006-October 2011), either as monotherapy or in combination with other antibiotics, for the treatment of cSSTI or cIAI were used in the analysis.

RESULTS

The total population (N=1782 patients) was divided into three age categories: <65 years (804 patients); 65-80 years (836 patients) and >80 years (139 patients) (data unknown/missing for 3 patients). The overall mean Acute Physiology and Chronic Health Evaluation (APACHE) II score for patients with cSSTI and cIAI was 15.0±7.9 and 16.9±7.6, respectively, and the overall mean Sequential Organ Failure Assessment (SOFA) score was 5.8±3.9 and 7.0±4.2, respectively. Overall, patients with cSSTI and cIAI in the three age groups showed a good response to tigecycline treatment (76.2-80.0% and 69.2-81.1%, respectively) with patients aged ≤80 years showing higher response rates. Patients with cIAI appeared to be at greater risk for all types of adverse events compared with those with cSSTI, particularly in the older age groups.

CONCLUSION

In these real-life studies, tigecycline, either alone or in combination, achieved favourable clinical response rates in all age categories of patients with cSSTIs and cIAIs with a high severity of illness.

Comparative efficacy and safety of antibiotics used to treat acute bacterial skin and skin structure infections: Results of a network meta-analysis

OBJECTIVE

This NMA compared the efficacy and safety between IV antibiotics that are used in the current standard of care for managing adult patients (≥18 years of age) with ABSSSI.

METHODS

Comparators were chosen on the basis that both direct and indirect comparisons between the interventions of interest could be performed. Outcomes of the analysis were selected on the basis that they are frequently measured and reported in trials involving ABSSSI patients, and only published randomised control trials of any size and duration and with any blinding status were eligible for inclusion in the analysis. The NMA was performed using both a fixed-effect and random-effect model. Efficacy-related endpoints were (1) clinical treatment success and (2) microbiological success at TOC visit. Safety-related endpoints were (1) number of discontinuations due to AEs/SAEs, (2) patients experiencing AEs, (3) patients experiencing SAEs and (4) all-cause mortality.

RESULTS

Study interventions included daptomycin, dalbavancin, linezolid and tigecycline. Vancomycin was the comparator in all studies, except in two where it was linezolid and teicoplanin. The NMA showed that irrespective of patient subgroup, the likelihood of clinical and microbiological success with dalbavancin was statistically similar to the comparators studied. No statistically significant differences were observed between dalbavancin and any of the comparators in the discontinuation rate due to AEs/SAEs. In contrast, dalbavancin was associated with a significantly lower likelihood of experiencing an AE than linezolid, a significantly lower likelihood of experiencing a SAE than vancomycin and daptomycin, and a significantly lower risk of all-cause mortality than vancomycin, linezolid and tigecycline.

CONCLUSION

Dalbavancin affords a promising, new alternative IV antimicrobial agent which is as effective as traditional therapies, but with the added benefit of enabling clinicians to treat patients with ABSSSI in different organisational settings. Notwithstanding, any introduction of an effective treatment with a differential mode of administration into healthcare systems must be followed by a change in clinical practice and patient management in order to fully achieve desirable economic outcomes.

Efficacy of intravenous tigecycline in patients with Acinetobacter complex infections: results from 14 Phase III and Phase IV clinical trials

Background

Acinetobacter infections, especially multidrug-resistant (MDR) Acinetobacter infections, are a global health problem. This study aimed to describe clinical outcomes in patients with confirmed Acinetobacter spp. isolates who were treated with tigecycline in randomized clinical trials.

Materials and methods

Data from 14 multinational, randomized (open-label or double-blind), and active-controlled (except one) Phase III and IV studies were analyzed using descriptive statistics.

Results

A total of 174 microbiologically evaluable patients with Acinetobacter spp. infections (including MDR infections) were identified, and 95 received tigecycline to treat community-acquired pneumonia (CAP), diabetic foot infections (DFIs), hospital-acquired pneumonia (HAP), complicated intra-abdominal infections (cIAIs), infections with resistant pathogens (RPs), or complicated skin and skin-structure infections. The rate of cure of tigecycline for most indications was 70%–80%, with the highest (88.2%) in cIAIs. The rate of cure of the comparators was generally higher than tigecycline, but within each indication the 95% CIs for clinical cure for each treatment group overlapped. For most Acinetobacter isolates, the minimum inhibitory concentration of tigecycline was 0.12–2 μg/mL, with seven at 4 μg/mL and one at 8 μg/mL. The cure rate by tigecycline was 50% (95% CI 12.5%–87.5% in CAP) to 88.2% (95% CI 66.2%–97.1% in cIAIs) for all Acinetobacter, and 72.7% (95% CI 54.5%–93.2% in HAP) to 100% (95% CI 25%–100.0% in cIAIs) for MDR Acinetobacter. For the comparators, it was 83.8% (95% CI 62.8%–95.9% in HAP) to 100% (95% CI 75%–100% in cIAIs and 25%–100.0% in RPs) and 88% (95% CI 66%–97% in HAP) to 100% (95% CI 25%–100% in cIAIs and 75%–100% in DFIs), respectively.

Conclusion

These findings suggest that with appropriate monitoring, tigecycline may be a useful consideration for Acinetobacter infections alone or in combination with other anti-infective agents when other therapies are not suitable.

The efficacy and safety of tigecycline for the treatment of bloodstream infections: a systematic review and meta-analysis

Patients with bloodstream infections (BSI) are associated with high mortality rates. Due to tigecycline has shown excellent in vitro activity against most pathogens, tigecycline is selected as one of the candidate drugs for the treatment of multidrug-resistant organisms infections. The purpose of this study was to evaluate the effectiveness and safety of the use of tigecycline for the treatment of patients with BSI. The PubMed and Embase databases were systematically searched, to identify published studies, and we searched clinical trial registries to identify completed unpublished studies, the results of which were obtained through the manufacturer. The primary outcome was mortality, and the secondary outcomes were the rate of clinical cure and microbiological success. 24 controlled studies were included in this systematic review. All-cause mortality was lower with tigecycline than with control antibiotic agents, but the difference was not significant (OR 0.85, [95% confidence interval (CI) 0.31-2.33; P = 0.745]). Clinical cure was significantly higher with tigecycline groups (OR 1.76, [95% CI 1.26-2.45; P = 0.001]). Eradication efficiency did not differ between tigecycline and control regimens, but the sample size for these comparisons was small. Subgroup analyses showed good clinical cure result in bacteremia patients with CAP. Tigecycline monotherapy was associated with a OR of 2.73 (95% CI 1.53-4.87) for mortality compared with tigecycline combination therapy (6 studies; 250 patients), without heterogeneity. Five studies reporting on 398 patients with Klebsiella pneumoniae carbapenemase-producing K. pneumoniae BSI showed significantly lower mortality in the tigecycline arm than in the control arm. The combined treatment with tigecycline may be considered the optimal option for severely ill patients with BSI.

New therapeutic options for skin and soft tissue infections

PURPOSE OF REVIEW

The occurrence of methicillin-resistance in Staphylococcus aureus, that represents the most frequent cause of complicated skin and soft tissue infections (cSSTIs) worldwide, is a major concern and has been associated with increased length of stay, health care costs, and overall mortality. Although vancomycin is still considered the standard therapy in this setting, limitations of its use in clinical practice are represented by a progressive increase in methicillin-resistant S. aureus (MRSA) minimum inhibitory concentrations, drug-related toxicity, and the lack of an oral formulation. New therapeutic options for MRSA cSSTIs have recently become available, with promising implications for the management of cSSTIs in clinical practice.

RECENT FINDINGS

A number of new antimicrobials with activity against MRSA have been recently approved for the treatment of cSSTIs, and other agents are under investigation. We have reviewed the recent developments, with a specific focus on the possible advantages of new drugs for the management of cSSTIs into the everyday clinical practice.

SUMMARY

The new approved drugs for the treatment of cSSTIs are expected to offer many advantages for the management of patients with suspected or confirmed MRSA cSSTIs. The most promising features of the new compounds include the availability of oral formulations, once-weekly intravenous regimens, and broad spectra of activity.

Characteristics of superinfections during treatment with tigecycline

Tigecycline has a broad-spectrum in vitro activity against Gram-positive and Gram-negative bacteria, including multidrug-resistant (MDR) strains. However, some Gram-negative bacteria are intrinsically resistant or have reduced susceptibility to tigecycline. We performed a prospective, observational study of 43 patients who received tigecycline as the treatment for serious infections due to MDR Gram-negative microorganisms, to evaluate superinfections. In 60.5% of our patients, tigecycline-resistant (T-R) Gram-negative microorganisms were isolated, representing superinfection in 37.2% and colonization in 23.5%. Pseudomonas aeruginosa was the predominant pathogen (48.4%) followed by Providencia stuartii, Proteus mirabilis and Stenotrophomonas maltophilia. Median time elapsed between tigecycline prescription and isolation of T-R pathogens was 7 days. The 16 superinfections consisted of ventilator-associated pneumonias (43.75%), catheter-related bloodstream infections (37.5%), intra-abdominal infections (12.5%) and urinary tract infection (6.25%). Attributed mortality to superinfections was 31.25%. The comparison of various potential risk factors for isolation of T-R microorganisms did not reveal statistically significant results.

Efficacy and safety of tigecycline for the treatment of severe infectious diseases: an updated meta-analysis of RCTs

OBJECTIVES

To assess the efficacy and safety of tigecycline in comparison with other antimicrobial treatments for infectious diseases.

DESIGN

Databases of PubMed, Embase and the Cochrane Library were searched through Feb. 2015. The reference lists of the initially identified articles and systemic review articles were manually searched. Randomized controlled trials assessing tigecycline and other antibiotics for infectious diseases in adult patients were included.

RESULTS

Fifteen RCTs including 7689 cases were identified. We found that tigecycline was not as effective as the comparator agents for clinical treatment success (for the clinically evaluable population, odds ratio [OR] = 0.83, 95% confidence interval [CI] = (0.73, 0.96), P=0.01; for the clinically modified intent-to-treat (mITT) population, OR = 0.81, 95% CI = (0.72, 0.92), P=0.001). There was no significant difference in microbiological treatment success with lower eradication rate in tigecycline versus comparators (for the microbiologically evaluable population, OR = 0.94, 95% CI = (0.77, 1.16), P=0.56; for the microbiological mITT populations, OR = 0.91, 95% CI = (0.74, 1.11), P=0.35). Adverse events and all-cause mortality were more common in the tigecycline group.

CONCLUSIONS

Tigecycline is not as effective as other antibiotics with relatively more frequency of adverse events and higher mortality rate.

Comparative efficacy of antibiotics for the treatment of acute bacterial skin and skin structure infections (ABSSSI): a systematic review and network meta-analysis

OBJECTIVE

The objective was to conduct a systematic review and network meta-analysis (NMA) of existing treatments for ABSSSI focusing on the novel lipoglycopeptide oritavancin.

METHODS

EMBASE, MEDLINE, MEDLINE in Process, CENTRAL (Cochrane), and select conferences were searched for randomized controlled trials investigating antimicrobial agents for the treatment of ABSSSI. NMA was used to estimate the odds ratios of the Test-Of-Cure (TOC) and Early Clinical Response (ECR) outcomes for treatments relative to vancomycin in the ITT populations. Sub-group analyses in MRSA and MSSA populations were conducted for TOC; sensitivity analyses investigated the use of the clinically evaluable (CE) populations and the restriction to trials following the recent FDA guidelines for clinical trials.

RESULTS

The systematic review identified 52 trials. The most commonly investigated treatments were vancomycin and linezolid; most trials reported TOC, but not ECR. The posterior mean and 95% credible intervals for odds ratios of TOC for antimicrobial agents relative to vancomycin were: linezolid (1.55; 0.91-2.57), daptomycin (2.18; 0.90-5.42), and oritavancin 1200 mg (1.06; 0.80-1.43). The odds ratio of ECR for oritavancin 1200 mg was 1.02 (0.23-4.33). In the MRSA sub-group the odds ratios relative to vancomycin for TOC were: linezolid (1.55; 0.96-2.46), daptomycin (0.74; 0.13-3.66), and oritavancin 1200 mg (0.94; 0.44-2.02). In the MSSA sub-group they were linezolid (1.36; 0.15-13.34) and oritavancin 1200 mg (0.82; 0.08-7.83). These results were robust to the sensitivity analyses.

CONCLUSIONS

This NMA provides a unified framework for the comparison of all available antimicrobial agents used in the treatment of ABSSSI and is the first to assess the ECR end-point. The results suggest equivalence of clinical efficacy between vancomycin, daptomycin, linezolid, and novel antimicrobial agents including oritavancin for the treatment of ABSSSI at TOC. The wide uncertainty margins indicate the heterogeneity of the available evidence and the need for further research.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Clinical response and mortality in tigecycline complicated intra-abdominal infection and complicated skin and soft-tissue infection trials

An imbalance in all-cause mortality was noted in tigecycline phase 3 and 4 comparative clinical trials across all studied indications. We investigated clinical failure and mortality in phase 3 and 4 complicated skin and soft-tissue infection (cSSTI) and complicated intra-abdominal infection (cIAI) tigecycline trials using descriptive analyses of a blinded adjudication of mortality and multivariate regression analyses. Attributable mortality analyses of cSSTI revealed death due to infection in 0.1% of each treatment group (P=1.000). In cIAI, there were no significant differences between tigecycline (1.2%) and comparator (0.7%) subjects who died due to infection (P=0.243). For cIAI clinical failure, treatment interaction with organ dysfunction was observed with no difference observed between clinical cure for tigecycline (85.4%) and comparator (76.7%) treatment groups (odds ratio=0.58, 95% confidence interval 0.28-1.19). Tigecycline-treated subjects had more adverse events of secondary pneumonias (2.1% vs. 1.2%) and more adverse events of secondary pneumonias with an outcome of death (0.5% vs. 0.1%). These analyses do not suggest that tigecycline is a factor either for failure (cSSTI and cIAI studies) or for death (cIAI studies).

Tigecycline use in critically ill patients: a multicentre prospective observational study in the intensive care setting

PURPOSE

This prospective observational study aimed at describing prescription patterns of tigecycline and patient outcomes in 26 French intensive care units (ICU).

METHODS

Data of consecutive cases of adult patients treated with tigecycline were collected from the initiation until 7 days after the end of treatment. Response to treatment was classified as success, failure or undetermined and analyses were presented according to severity (SOFA score <7 or ≥7). Survival was recorded at 28 days.

RESULTS

A total of 156 patients were included (64% male, age 60 ± 15 years). At inclusion, 53% had a SOFA score ≥7; 93% had received prior anti-infective agents. Tigecycline was given as first-line treatment in 47% of patients, mostly in combination (67%), for intra-abdominal (IAI 56%), skin and soft tissue (SSTI 19%) or other infections. A total of 76% of the treated infections were hospital-acquired. Bacteraemia was reported in 12% of patients. Median treatment duration was 9 days. Tigecycline was prematurely stopped in 42% patients. The global success rate was 60% at the end of treatment, and significantly higher with treatment duration more than 9 days (76 vs. 47%, P < 0.001). Success rate was 65% for patients alive at the end of treatment. Success rates tended to decrease with illness severity, immunosuppression, bacteraemia and obesity. Survival rate at day 28 was 85% in the whole cohort and significantly higher in the less severely ill patients (P < 0.001).

CONCLUSIONS

Tigecycline success rates appear comparable to those reported in clinical studies in ICU with severe infections. Tigecycline could be an alternative in ICU patients.

Clinical experience in 52 patients with tigecycline-containing regimens for salvage treatment of Mycobacterium abscessus and Mycobacterium chelonae infections

OBJECTIVES

We report the largest clinical experience using tigecycline-containing regimens for salvage treatment of patients with Mycobacterium abscessus and Mycobacterium chelonae.

PATIENTS AND METHODS

Data were collected from 52 patients on emergency/compassionate use (n = 38) or two open-label studies (n = 7 patients each). Based on information that was available, 46 (88.5%) of the subjects received antibiotic therapy prior to treatment with tigecycline. Treatment groups were evaluated based on length of tigecycline therapy (<1 and ≥1 month). ClinicalTrials.gov identifiers: Study 205, NCT00600600 and Study 310, NCT00205816.

RESULTS

The most commonly used concomitant antimicrobials were macrolides, amikacin and linezolid. Pulmonary disease was the most common presentation (36/52; 69.2%), and 58.3% of these patients had underlying cystic fibrosis. The majority were M. abscessus complex (n = 30) or M. chelonae/abscessus (n = 4). With therapy ≥1 month (mean, 255.0 ± 265.7 days), 10/15 patients (66.7%) with cystic fibrosis and 16/26 (61.5%) overall were considered improved. Skin/soft-tissue/bone infections were the most common extrapulmonary infections. With therapy ≥1 month (mean, 143 ± 123 days), 9/12 patients (75.0%) were considered improved. Nine of the 16 cases reported as failures regardless of site of infection occurred in patients who stopped treatment due to adverse events. There were eight deaths; none was related to tigecycline.

CONCLUSIONS

Tigecycline given for ≥1 month as part of a multidrug regimen resulted in improvement in >60% of patients with M. abscessus and M. chelonae infections, including those with underlying cystic fibrosis, despite failure of prior antibiotic therapy. Adverse events were reported in >90% of cases, the most common being nausea and vomiting.

Methicillin-resistant Staphylococcus aureus infection epidemiology and clinical response from tigecycline soft tissue infection trials

Given increasing resistance, therapeutic options to treat MRSA soft tissue infections should be evaluated. This pooled analysis evaluated data from subjects enrolled in 6 tigecycline clinical trials with documented MRSA complicated skin and skin structure infections or diabetic foot infections (DFIs). Baseline characteristics were compared between subjects with and without molecularly classified community-acquired (CA) MRSA, specifically staphylococcal cassette chromosome mec (SCCmec) IV. Clinical response was compared by CA-MRSA designation and treatment group. A total of 378 subjects with MRSA soft tissue infections were identified, including 79 with DFI. A total of 249 (65.9%) were molecularly classified as CA-MRSA. Clinical response rates for MRSA soft tissue infection were similar between tigecycline and vancomycin (treatment difference, 1.0%; 95% confidence interval: -9.3, 12.0) as well as by infection type, SCCmec, and Panton-Valentine leukocidin (PVL) status. Tigecycline demonstrated comparable efficacy for treatment of MRSA soft tissue infections regardless of infection type, SCCmec, or PVL status.

Efficacy of tigecycline for the treatment of complicated skin and soft-tissue infections in real-life clinical practice from five European observational studies

OBJECTIVES

Tigecycline is an approved treatment for complicated skin and soft-tissue infections (cSSTIs). The efficacy of tigecycline as monotherapy or in combination with other antibacterials in the treatment of cSSTI in routine practice is described.

PATIENTS AND METHODS

Individual patient-level data were pooled from five European observational studies (July 2006 to October 2011).

RESULTS

A total of 254 cSSTI patients who received tigecycline were included (mean age 63.2 ± 14.9 years). Of these, 34.4% were in intensive care units, 54.5% acquired their infection in hospital and 90.9% had at least one comorbidity. Infection most commonly affected the limbs (62.4%) and 43.8% of infections were classified as necrotizing. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at the beginning of treatment were 15.0 ± 7.9 (n = 205) and 5.8 ± 3.9 (n = 32), respectively, indicating high disease severity. Staphylococcus aureus (52.7%), Escherichia coli (18.0%) and Enterococcus faecium (12.0%) were the most frequently isolated pathogens; 32.9% of infections were polymicrobial and 30.5% were due to resistant pathogens. Overall, 71.8% received tigecycline as monotherapy and 28.2% as combination therapy for a mean duration of 12 days. Clinical response rates at the end of treatment were 79.6% for all patients who received the standard dosage (183/230), 86.7% for patients who received tigecycline as monotherapy (143/165), 75.0% for patients with a nosocomial infection (96/128), 75.3% for patients with an APACHE II score >15 (61/81) and 58.3% for patients with a SOFA score ≥ 7 (7/12).

CONCLUSIONS

In these real-life studies, tigecycline, alone and in combination, achieved favourable clinical response rates in patients with cSSTI with a high severity of illness.

Prescription behaviours for tigecycline in real-life clinical practice from five European observational studies

OBJECTIVES

There is limited information on the use of tigecycline in real-life clinical practice. This analysis aims to identify and understand tigecycline prescribing patterns and associated patient outcomes for approved indications.

PATIENTS AND METHODS

A pooled analysis of patient-level data collected on the prescription of tigecycline in five European observational studies (July 2006 to October 2011) was conducted.

RESULTS

A total of 1782 patients who received tigecycline were included in the analysis. Of these patients, 61.6% were male, the mean age was 63.4 ± 14.7 years, 56.4% were in intensive care units, 80.2% received previous antibiotic treatment and 91% had one or more comorbid conditions. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores at the beginning of treatment were 17.7 ± 7.9 and 7.0 ± 4.0, respectively. The majority of patients (58.3%) received tigecycline for treatment of complicated skin and soft-tissue infections (cSSTIs; n = 254) or complicated intra-abdominal infections (cIAIs; n = 785). Tigecycline was given at the standard dose (100 mg plus 50 mg twice daily) to 89.3% of patients for a mean duration of 11.1 ± 6.4 days. The main reasons for prescribing tigecycline were failure of previous therapy (46.1%), broad-spectrum antibiotic coverage (41.4%) and suspicion of a resistant pathogen (39.3%). Tigecycline was prescribed first-line in 36.3% of patients and as monotherapy in 50.4%. Clinical response rates to treatment with tigecycline alone or in combination were 79.6% (183/230; cSSTIs) and 77.4% (567/733; cIAIs).

CONCLUSIONS

Although tigecycline prescription behaviour showed some heterogeneity across the study sites, these results confirm a role for tigecycline in real-life clinical practice for the treatment of complicated infections, including those in critically ill patients, across Europe.

Resistance mechanisms and epidemiology of multiresistant pathogens in Europe and efficacy of tigecycline in observational studies

OBJECTIVES

Antimicrobial drug resistance is a growing problem in Europe and, even with differences in epidemiology, it is of great concern. The treatment of complicated skin and soft-tissue infections (cSSTIs) and complicated intra-abdominal infections (cIAIs) is hindered further by pathogens that are resistant to methicillin, carbapenems, third-generation cephalosporins and glycopeptides.

PATIENTS AND METHODS

An analysis of the microbiological results from five European observational studies (July 2006 to October 2011) evaluating the efficacy of tigecycline (prescribed as monotherapy or in combination with other antibacterials) for the treatment of cSSTI and cIAI is presented.

RESULTS

In total, 213 cSSTI and 623 cIAI patients were included; 34.4% and 56.6%, respectively, were critically ill in intensive care units. At baseline, at least one pathogen was isolated in 167 (78.4%) cSSTI and 464 (74.5%) cIAI patients, and 32.9% and 49.1% of infections were polymicrobial. In cSSTI, Staphylococcus aureus and Escherichia coli (52.7% and 18.0%, respectively) were the most frequently isolated pathogens, whereas in cIAI most infections were due to E. coli (41.8%), Enterococcus faecium (40.1%) and Enterococcus faecalis (21.1%). Clinical response was observed in >80% of patients with E. coli in both cIAI and cSSTI. In cSSTI patients, the clinical response rate to S. aureus was 80.8%. For cIAI, 77.4% of E. faecium and 79.5% of E. faecalis patients responded to treatment.

CONCLUSIONS

Tigecycline when given alone or in combination with other antibacterials appeared to be efficacious against multiple pathogens, affirming its role in real-life clinical practice as a broad-spectrum antibacterial for the treatment of patients with cSSTI and cIAI, including the critically ill, across Europe.

Pharmacokinetics, Pharmacodynamics, Safety and Tolerability of Tigecycline

The pharmacokinetics and pharmacodynamics of tigecycline have been extensively studied in laboratory models and healthy volunteers. Tigecycline is available as a parenteral agent, exhibits linear pharmacokinetics, has a long terminal half-life, is extensively distributed into the tissues and attains steady-state levels in serum by day 7. The pharmacokinetics of tigecycline appear unaffected by age, renal disease and food. Clinical trials have shown that tigecycline (50 mg i.v. q12h) in adults is safe and generally well tolerated for up to 11.5 days. Drug-related adverse events, which are typically mild to moderate in intensity and of limited duration, mainly include nausea and vomiting. Tolerability of tigecycline in fasting subjects is improved by the use of antiemetics. C. difficile-related complications with tigecycline are uncommon. In the majority of patients, tigecycline has minimal adverse effects on blood chemistry or haematology.

An alternate pathophysiologic paradigm of sepsis and septic shock: implications for optimizing antimicrobial therapy

The advent of modern antimicrobial therapy following the discovery of penicillin during the 1940s yielded remarkable improvements in case fatality rate of serious infections including septic shock. Since then, pathogens have continuously evolved under selective antimicrobial pressure resulting in a lack of significant improvement in clinical effectiveness in the antimicrobial therapy of septic shock despite ever more broad-spectrum and potent drugs. In addition, although substantial effort and money has been expended on the development novel non-antimicrobial therapies of sepsis in the past 30 years, clinical progress in this regard has been limited. This review explores the possibility that the current pathophysiologic paradigm of septic shock fails to appropriately consider the primacy of the microbial burden of infection as the primary driver of septic organ dysfunction. An alternate paradigm is offered that suggests that has substantial implications for optimizing antimicrobial therapy in septic shock. This model of disease progression suggests the key to significant improvement in the outcome of septic shock may lie, in great part, with improvements in delivery of existing antimicrobials and other anti-infectious strategies. Recognition of the role of delays in administration of antimicrobial therapy in the poor outcomes of septic shock is central to this effort. However, therapeutic strategies that improve the degree of antimicrobial cidality likely also have a crucial role.

Comparative analysis of empiric antimicrobial treatments for skin and soft tissue infections in newly hospitalized patients

PURPOSE

Intravenous vancomycin is the standard empiric treatment for complicated skin and soft tissue infections (SSTIs) due to its coverage against methicillin-resistant Staphylococcus aureus (MRSA). The objective of this study was to compare the hospital length of stay (LOS) between vancomycin-treated patients and patients receiving newer anti-MRSA agents. The study also aimed to identify factors associated with therapy change in patients receiving vancomycin on admission.

METHODS

Electronic medical records were used to conduct this retrospective cohort study. The LOS was compared among 5 groups of adult patients with admission diagnoses for SSTI who were initiated on linezolid, daptomycin, ceftaroline, tigecycline, or vancomycin. Survival analysis was used to identify factors associated with therapy change from vancomycin to another study medication.

RESULTS

Vancomycin was prescribed in 1046 (92%) admissions. Although none of the between-group differences in LOS reached statistical significance, there was a trend toward shorter LOS in vancomycin-treated patients compared to linezolid-treated patients (P = .059). Coagulopathy was independently associated with increased likelihood of therapy change from vancomycin (hazard ratio = 4.71; P <.001).

CONCLUSIONS

In the treatment of SSTI, newer agents result in LOS comparable to vancomycin. In patients initiated on vancomycin, therapy change was associated with longer LOS. Coagulopathy was independently associated with increased probability of therapy change.

Tigecycline in febrile neutropenic patients with haematological malignancies: a retrospective case documentation in four university hospitals

OBJECTIVES

Tigecycline (TGC) is a first-in-class glycylcycline with an expanded spectrum of activity. Although TGC has not been prospectively studied in febrile neutropenia (FN), we observed that occasionally critically ill neutropenic patients unresponsive to other antibiotics were treated with TGC in our departments. The aim of our study was to analyse effectiveness and toxicity of TGC in FN.

METHODS

Data of infectious episodes treated with TGC were retrospectively collected. Baseline data of patients, haematological malignancy, infection and adverse events were documented. Success was defined as defervescence (≥7 days) in the absence of any sign of persistent infection.

RESULTS

Data of 35 patients with haematological malignancies and FN were evaluated. Median duration of neutropenia was 25 days (range 6-69 days). The type of infection was pneumonia in 24 patients, four microbiologically documented infections, three clinically documented infections and four with fever of unknown origin. The TGC was administered after a median of two (range 1-5) prior antibiotic regimens. Treatment was successful in 15 (43 %) patients. In patients with prolonged neutropenia (≥28 days), response was significantly lower (13 vs. 79 %; p =0.001). Eight (23 %) patients died during the fever episode. Grade 3-4 toxicity occurred in five (14 %) patients.

CONCLUSION

Our results showed promising response rates to TGC and very low toxicity rates compared to the generally low response rate of third-line antibiotic therapies, indicating that TGC may be a successful alternative for salvage treatment of febrile neutropenia, but further study is needed.

Clinical and microbiological efficacy of tigecycline for complicated skin-soft-tissue and intra-abdominal infections in a Turkish university hospital

OBJECTIVE

Tigecycline, a new glycylcycline antimicrobial agent, is indicated for the treatment of complicated skin structure infection (cSSTI), intra-abdominal infection (cIAI) and community acquired pneumonia. We aimed to evaluate the clinical and microbiological data together about tigecycline therapy.

METHODS

Patients with cIAIs and cSSTIs were included in a prospective, observational follow-up. Patient follow-up forms were developed and clinical and microbiological data were recorded.

RESULTS

Of the 107 patients, 67 had cSSTIs, 40 had cIAIs. Tigecycline was used empirically in 37.5% of cIAIs and in 50.7% of cSSTIs. In 85.0% of the patients with cIAI and in 73.1% of the patients with cSSTI, clinical and/or microbiological response could be achieved. A drug change was made in 26.9% and 7.5% of the patients with cSSTI and cIAI respectively. Superinfection was detected in 14.9% of the cSSTI and 7.5% of the cIAI patients.

CONCLUSION

As a result, tigecycline can be safely used in the treatment of different infections. Compared with cSSTIs, the treatment response is better and the duration of treatment is shorter in cIAIs. However, MIC value must be determined at any rate if tigecycline is to be used in the treatment of Acinetobacter (MDR Acinetobacter, in particular) infections. Clinical cure and microbiological eradication rate of tigecycline therapy changes according to different clinical diagnosis and microorganism.

Tigecycline does not prolong corrected QT intervals in healthy subjects

We evaluated the effect of tigecycline (50-mg and 200-mg doses) on corrected QT (QTc) intervals and assessed safety and tolerability in a randomized, placebo-controlled, four-period crossover study of 48 (44 male) healthy volunteers aged 22 to 53 years. Fed subjects received tigecycline (50 mg or 200 mg) or placebo in a blinded fashion or an open-label oral dose of moxifloxacin (400 mg) after 1 liter of intravenous fluid. Serial electrocardiograms were recorded before, and for 96 h after, dosing. Blood samples for tigecycline pharmacokinetics were collected after each recording. QTc intervals were corrected using Fridericia's correction (QTcF). Pharmacokinetic parameters were calculated using noncompartmental methods with potential relationships examined using linear mixed-effects modeling. Adverse events were recorded. The upper limits of the 90% confidence interval for the mean difference between both tigecycline doses and placebo for all time-matched QTcF interval changes from baseline were <5 ms. The tigecycline concentrations initially declined rapidly and then more slowly. In the group given 50 mg of tigecycline, the pharmacokinetic parameters and means were as follows: maximum concentration of drug in serum (C(max)), 432 ng/ml; area under the concentration-time curve from time zero extrapolated to infinity (AUC0-∞), 2,366 ng · h/ml; clearance (CL), 21.1 liters/h; volume of distribution at steady state (V(ss)), 610 liters; and terminal half-life (t(1/2)), 22.1 h. Proportional or similar values were found for the group given 200 mg of tigecycline. Linear mixed-effects modeling failed to show an effect on QTcF values by tigecycline concentrations (P = 0.755). Tigecycline does not prolong the QTc interval in healthy subjects. This study has been registered at ClinicalTrials.gov under registration no. NCT01287793.

A randomized trial of tigecycline versus ampicillin-sulbactam or amoxicillin-clavulanate for the treatment of complicated skin and skin structure infections

BACKGROUND

Complicated skin and skin structure infections (cSSSIs) frequently result in hospitalization with significant morbidity and mortality.

METHODS

In this phase 3b/4 parallel, randomized, open-label, comparative study, 531 subjects with cSSSI received tigecycline (100 mg initial dose, then 50 mg intravenously every 12 hrs) or ampicillin-sulbactam 1.5-3 g IV every 6 hrs or amoxicillin-clavulanate 1.2 g IV every 6-8 hrs. Vancomycin could be added at the discretion of the investigator to the comparator arm if methicillin-resistant Staphylococcus aureus (MRSA) was confirmed or suspected within 72 hrs of enrollment. The primary endpoint was clinical response in the clinically evaluable (CE) population at the test-of-cure (TOC) visit. Microbiologic response and safety were also assessed. The modified intent-to-treat (mITT) population comprised 531 subjects (tigecycline, n = 268; comparator, n = 263) and 405 were clinically evaluable (tigecycline, n = 209; comparator, n = 196).

RESULTS

In the CE population, 162/209 (77.5%) tigecycline-treated subjects and 152/196 (77.6%) comparator-treated subjects were clinically cured (difference 0.0; 95% confidence interval [CI]: -8.7, 8.6). The eradication rates at the subject level for the microbiologically evaluable (ME) population were 79.2% in the tigecycline treatment group and 76.8% in the comparator treatment group (difference 2.4; 95% CI: -9.6, 14.4) at the TOC assessment. Nausea, vomiting, and diarrhea rates were higher in the tigecycline group.

CONCLUSIONS

Tigecycline was generally safe and effective in the treatment of cSSSIs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00368537.

Excess deaths associated with tigecycline after approval based on noninferiority trials

BACKGROUND

On the basis of noninferiority trials, tigecycline received Food and Drug Administration (FDA) approval in 2005. In 2010, the FDA warned in a safety communication that tigecycline was associated with an increased risk of death.

METHODS

PubMed, EMBASE, Scopus, and ClinicalTrials.gov were searched using the terms "tigecycline" and "randomized controlled trial (RCT)" through April 2011. Excess deaths and noncure rates for both approved and nonapproved indications were examined using meta-analysis.

RESULTS

Ten published and 3 unpublished studies met inclusion criteria (N = 7434). No significant heterogeneity was seen for mortality (I(2 )= 0%; P = .99) or noncure rates (I(2 )= 25%; P = .19). Across randomized controlled trials, tigecycline was associated with increased mortality (risk difference [RD], 0.7%; 95% confidence interval [CI], 0.1%-1.2%; P = .01) and noncure rates (RD, 2.9%; 95% CI, 0.6%-5.2%; P = .01). Effects were not isolated to type of infection or comparator antibiotic regimen, and the impact on survival remained significant when limited to trials of approved indications (I(2 )= 0%; RD, 0.6%; P = .04). A pooled analysis of the 5 trials completed by early 2005 before tigecycline was approved would have demonstrated a similar harmful effect of tigecycline on survival (I(2 )= 0%; RD, 0.7%; P = .06).

CONCLUSIONS

Pooling noninferiority studies to examine survival may help ensure the safety and efficacy of new antibiotics. The association of tigecycline with excess deaths and noncure includes indications for which it is approved and marketed. Tigecycline cannot be relied on in serious infections.

In vivo emergence of tigecycline resistance in multidrug-resistant Klebsiella pneumoniae and Escherichia coli

Although resistance to tigecycline has been reported in surveillance studies, very few reports have described the emergence of resistance in vivo. We report two cases of patients with infections due to SHV-12-producing Klebsiella pneumoniae and K. pneumoniae carbapenemase-3 (KPC-3)-producing Escherichia coli, which developed tigecycline resistance in vivo after treatment. The reported limited experience underlines the risk of occurrence of a tigecycline MIC increase under treatment pressure.

Meta-analysis of randomized controlled trials of vancomycin for the treatment of patients with gram-positive infections: focus on the study design

OBJECTIVE

To study the effectiveness and safety of vancomycin compared with that of other antibiotics for the treatment of gram-positive infections.

METHODS

Major electronic databases were searched. Data from published randomized controlled trials (January 1, 1950, to September 15, 2011) were pooled using a meta-analytic method.

RESULTS

Fifty-three trials comparing vancomycin with linezolid, daptomycin, quinupristin-dalfopristin, tigecycline, ceftaroline, ceftobiprole, telavancin, teicoplanin, iclaprim, and dalbavancin were included in the meta-analysis. Individual antibiotics were as effective as vancomycin, except for linezolid, which was more effective than vancomycin for the treatment of skin and soft tissue infections (odds ratio [OR], 1.61; 95% confidence interval [CI], 1.07-2.43). Comparators were as effective as vancomycin in the intent-to-treat population (OR, 1.08; 95% CI, 0.98-1.18) but were more effective in the clinically evaluable population (OR, 1.14; 95% CI, 1.02-1.27) when all infections were pooled. When available data from all trials were pooled, no differences were noted when patients with febrile neutropenia (OR, 1.07; 95% CI, 0.82-1.39), pneumonia (OR, 1.10; 95% CI, 0.87-1.37), bacteremia (OR, 1.05; 95% CI, 0.76-1.45), and skin and soft tissue infections (OR, 1.11; 95% CI, 0.89-1.39) were studied. Comparators were more effective in open-label (OR, 1.28; 95% CI, 1.08-1.50) but not in double-blind trials (OR, 1.04; 95% CI, 0.90-1.20). Total adverse events attributed to studied antibiotics (OR, 1.07; 95% CI, 0.90-1.28) and patients withdrawn from trials (OR, 0.86; 95% CI, 0.68-1.09) were similar in the compared groups. Mortality was not different between vancomycin and comparator antibiotics when all trials were included in the analysis (OR, 1.09; 95% CI, 0.96-1.23). Comparators were associated with higher mortality in open-label (OR, 1.27; 95% CI, 1.05-1.54) but not double-blind trials (OR, 0.96; 95% CI, 0.80-1.14).

CONCLUSION

On the basis mainly of data from open-label trials, vancomycin is a treatment choice that is as effective as other available antibiotics for patients with gram-positive infections. Study design seems to make a major contribution to the outcome.

Pharmacokinetics and safety profile of tigecycline in children aged 8 to 11 years with selected serious infections: a multicenter, open-label, ascending-dose study

BACKGROUND

Tigecycline, a broad-spectrum antibiotic used for treating serious bacterial infections in adults, may be suitable for pediatric use once an appropriate dosage is determined.

OBJECTIVE

The aim of this study was to assess the pharmacokinetic (PK) properties, safety profile, and descriptive efficacy of tigecycline.

METHODS

In this Phase II, multicenter, open-label clinical trial, children aged 8 to 11 years with community-acquired pneumonia (CAP), complicated intra-abdominal infection (cIAI), or complicated skin and skin structure infections (cSSSI) were administered tigecycline 0.75, 1, or 1.25 mg/kg.

RESULTS

A total of 58 patients received ≥ 1 dose of tigecycline (31 boys; 44 white; mean age, 10 years; mean weight, 35 kg); 47 had data from samples available for PK analysis. The mean (SD) PK values were: C(max), 1899 (2954) ng/mL; T(max), 0.56 (0.18) hour; between-dose AUC, 2833 (1557) ng · h/mL; weight-normalized clearance, 0.503 (0.293) L/h/kg; and Vd(ss), 4.88 (4.84) L/kg. Overall clinical cure rates at test-of-cure were 94% (16/17), 76% (16/21), and 75% (15/20) in the 0.75-, 1-, and 1.25-mg/kg cohorts, respectively. The rates of protocol violations were higher in the 1- and 1.25-mg/kg groups, resulting in higher proportions of indeterminate clinical cure assessments relative to the 0.75-mg/kg cohort (19% and 15% vs 0%). The most frequent adverse event was nausea, which occurred in 50% of patients overall (29/58) and the prevalence of which was significantly higher in the 1.25-mg/kg group versus the 0.75-mg/kg group (65% vs 18%; P = 0.007). Pharmacodynamic simulations using MIC data from an ongoing microbiological surveillance trial predicted that a dosage of 1.2 mg/kg q12h would lead to therapeutic target attainment levels of up to 82% for the target AUC(0-24)/MIC ratios.

CONCLUSION

A tigecycline dosage of ∼1.2 mg/kg q12h may represent the most appropriate dosage for subsequent evaluation in Phase III clinical trials in children aged 8 to 11 years with selected serious bacterial infections. ClinicalTrials.gov identifier: NCT00488345.