Pharmacokinetics and safety of a single dose of telavancin in pediatric subjects 2-17 years of age

Antimicrobial resistance increases infection morbidity in both adults and children, necessitating the development of new therapeutic options. Telavancin, an antibiotic approved in the United States for certain bacterial infections in adults, has not been examined in pediatric patients. The objectives of this study were to evaluate the short-term safety and pharmacokinetics (PK) of a single intravenous infusion of telavancin in pediatric patients. Single-dose safety and PK of 10 mg/kg telavancin was investigated in pediatric subjects >12 months to ≤17 years of age with known or suspected bacterial infection. Plasma was collected up to 24-h post-infusion and analyzed for concentrations of telavancin and its metabolite for noncompartmental PK analysis. Safety was monitored by physical exams, vital signs, laboratory values, and adverse events following telavancin administration. Twenty-two subjects were enrolled: 14 subjects in Cohort 1 (12-17 years), 7 subjects in Cohort 2 (6-11 years), and 1 subject in Cohort 3 (2-5 years). A single dose of telavancin was well-tolerated in all pediatric age cohorts without clinically significant effects. All age groups exhibited increased clearance of telavancin and reduced exposure to telavancin compared to adults, with mean peak plasma concentrations of 58.3 µg/mL (Cohort 1), 60.1 µg/mL (Cohort 2), and 53.1 µg/mL (Cohort 3). A 10 mg/kg dose of telavancin was well tolerated in pediatric subjects. Telavancin exposure was lower in pediatric subjects compared to adult subjects. Further studies are needed to determine the dose required in phase 3 clinical trials in pediatrics.

Efficacy and mechanism of actions of natural antimicrobial drugs

Microbial infections have significantly increased over the last decades, and the mortality rates remain unacceptably high. The emergence of new resistance patterns and the spread of new viruses challenge the eradication of infectious diseases. The declining efficacy of antimicrobial drugs has become a global public health problem. Natural products derived from natural sources, such as plants, animals, and microorganisms, have significant efficacy for the treatment of infectious diseases accompanied by less adverse effects, synergy, and ability to overcome drug resistance. As the Chinese female scientist Youyou Tu received the Nobel Prize for the antimalarial drug artemisinin, antimicrobial drugs developed from Traditional Chinese Medicine are expected to receive increasing attention again. This review summarizes the antimicrobial agents derived from natural products approved for nearly 20 years and describes their efficacy and mode of action. The aim of this unit is to review the current status of antimicrobial drugs from natural products in order to increase the value of natural products as a source of novel drug candidates for infectious diseases.

Telavancin (VIBATIV) for the treatment of complicated skin and skin structure infections

Methicillin-resistant Staphylococcus aureus has emerged as a major causative pathogen in complicated skin and skin structure infections (cSSSIs). Unfortunately, treatment failure with vancomycin has been increasingly reported. Over the past decade, several alternative antimicrobial agents have been studied and approved for the treatment of cSSSIs. One such agent is the lipoglycopeptide telavancin, which was approved by the US FDA 2009. Given its dual mechanism of action, telavancin is characterized by a highly bactericidal activity and low potential for resistance selection. In addition, in clinical trials, it was efficacious and safe in the treatment of cSSSI. The purpose of this review is to give a background overview of telavancin, highlighting its microbiological, pharmacokinetic and pharmacodynamics characteristics, to summarize the available evidence for its use in the treatment of cSSSIs, and to provide an updated evaluation of its safety profile.

Quantitative determination of telavancin in pregnant baboon plasma by solid-phase extraction and LC-ESI-MS

The increasing incidence and severity of methicillin- and vancomycin-resistant infections during pregnancy prompted further development of telavancin. The understanding of the pharmacokinetics of telavancin during pregnancy is critical to optimize dosing. Due to ethical and safety concerns the study is conducted on the pregnant baboons. A method using solid-phase extraction coupled with liquid chromatography-single quadrupole mass spectrometry for the quantitative determination of telavancin in baboon plasma samples was developed and validated. Teicoplanin was used as an internal standard. Telavancin was extracted from baboon plasma samples by using Waters Oasis(®) MAX 96-Well SPE plate and achieved extraction recovery was >66% with variation <12%. Telavancin was separated on Waters Symmetry C18 column with gradient elution. Two SIM channels were monitored at m/z 823 and m/z 586 to achieve quantification with simultaneous confirmation of telavancin identification in baboon plasma samples. The linearity was assessed in the range of 0.188μg/mL to75.0μg/mL, with a correlation coefficient of 0.998. The relative standard deviation of this method was <11% for within- and between-run assays, and the accuracy ranged between 96% and 114%.

Population pharmacokinetics of telavancin in healthy subjects and patients with infections

A population pharmacokinetic model of telavancin, a lipoglycopeptide antibiotic, was developed and used to identify sources of interindividual variability. Data were obtained from healthy subjects (seven phase 1 studies), patients with complicated skin and skin structure infections (cSSSI; two phase 2 and two phase 3 studies), and patients with hospital-acquired pneumonia (HAP; two phase 3 studies). A two-compartment open model with zero-order input best fit the telavancin data from healthy individuals and patients with cSSSI or HAP. Telavancin clearance was highly correlated with renal function and, to a lesser extent, with body weight. Other covariates were related to at least one parameter in cSSSI (gender, bacterial eradication, and surgery) or HAP (age of ≥ 75 years) but did not markedly affect exposure. These analyses support current dosing recommendations for telavancin based on patient weight and renal function.

Telavancin pharmacokinetics and pharmacodynamics in patients with complicated skin and skin structure infections and various degrees of renal function

This study characterized the pharmacokinetic/pharmacodynamic profiles of the Food and Drug Administration (FDA)-approved telavancin renal dose adjustment schemes. A previously published two-compartment open model with first-order elimination and a combined additive and proportional residual error model derived from 749 adult subjects in 11 clinical trials was used to simulate the individual concentration-time profiles for 10,260 subjects (NONMEM). The dosing regimens simulated were 10 mg/kg of body weight once daily for individuals with creatinine clearances (CL(CR)s) of >50 ml/min, 7.5 mg/kg once daily for individuals with CL(CR)s of 30 to 50 ml/min, and 10 mg/kg every 2 days for those with CL(CR)s of <30 ml/min. The area under the concentration-time curve (AUC) under one dosing interval (AUC(τ)) was computed as dose/CL. The probability of achieving an AUC(τ)/MIC ratio of ≥ 219 was evaluated separately for each renal dosing scheme. Evaluation of the dosing regimens demonstrated similar AUC values across the different renal function groups. For all renal dosing strata, >90% of the simulated subjects achieved an AUC(τ)/MIC ratio of ≥ 219 for MIC values as high as 2 mg/liter. For patients with CL(CR)s of <30 ml/min, the probability of target attainment (PTA) exceeded 90% for both the AUC₀₋₂₄ (AUC from 0 to 24 h) and AUC₂₄₋₄₈ intervals for MICs of ≤ 1 mg/liter. At a MIC of 2 mg/liter, the PTAs were 89.3% and 23.6% for the AUC₀₋₂₄ and AUC₂₄₋₄₈ intervals, respectively. The comparable PTA profiles for the three dosing regimens across their respective dosing intervals indicate that the dose adjustments employed in phase III trials for complicated skin and skin structure infections were appropriate.

Telavancin: a lipoglycopeptide antimicrobial for the treatment of complicated skin and skin structure infections caused by gram-positive bacteria in adults

BACKGROUND

Telavancin, a lipoglycopeptide antibiotic, is a semisynthetic derivative of vancomycin. It was approved by the US Food and Drug Administration (FDA) in 2009 for the treatment of complicated skin and skin structure infections (cSSSIs) caused by gram-positive bacteria, including methicillin-resistant Staphylococcus aureus.

OBJECTIVE

This article summarizes the pharmacology, in vitro and in vivo activity, pharmacokinetic properties, and clinical efficacy and tolerability of telavancin.

METHODS

Relevant information was identified through a search of MEDLINE (1966-August 2010), Iowa Drug Information Service (1966-August 2010), International Pharmaceutical Abstracts (1970-August 2010), and Google Scholar using the terms telavancin, lipoglycopeptide, and TD-6424. Abstracts and posters from scientific meetings, as well as documents submitted by the manufacturer of telavancin to the FDA as part of the approval process, were consulted. In vivo and in vitro experimental and clinical studies and review articles that provided information on the activity, mechanism of action, pharmacologic and pharmacokinetic properties, clinical efficacy, and tolerability of telavancin were reviewed.

RESULTS

In vitro, telavancin has potent activity against S aureus, including methicillin-resistant strains; Streptococcus pneumoniae; and vancomycin-susceptible enterococci with MICs generally <1 μg/mL. Telavancin appears to have a dual mechanism of action, inhibiting cell wall formation and disrupting the cell membrane. In Phase III studies (ATLAS 1 and ATLAS 2), telavancin was found to be noninferior to vancomycin, with clinical cure rates of 88.3% and 87.1%, respectively, in clinically evaluable patients in the treatment of cSSSIs (difference, 1.2%; 95% CI, -2.1 to 4.6; P = NS). The effectiveness of telavancin in the treatment of hospital-acquired pneumonia was assessed in 2 Phase III studies (ATTAIN 1 and ATTAIN 2). Preliminary findings were that the effectiveness of telavancin was not significantly different from that of vancomycin, with cure rates of 82.7% and 80.9% in the clinically evaluable population, respectively (difference, 1.8%; 95% CI, -4.1 to 7.7; P = NS). The most commonly (>10%) reported adverse events included taste disturbances, nausea, headache, vomiting, foamy urine, constipation, and insomnia.

CONCLUSION

In clinical trials, the effectiveness of telavancin was not significantly different from that of vancomycin in the treatment of cSSSIs, and telavancin was generally well tolerated.

Telavancin, a new lipoglycopeptide antimicrobial, in complicated skin and soft tissue infections

Telavancin, a novel lipoglycopeptide with rapid concentration-dependent bactericidal effects, is a semisynthetic derivative of the glycopeptide, vancomycin. Telavancin has a dual mechanism of action, ie, inhibition of peptidoglycan polymerization and disruption of the bacterial membrane. It has linear pharmacokinetics, rapid bactericidal killing, and broad spectrum activity against Gram positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus. Phase II and III clinical trials for complicated skin and skin structure infections have shown telavancin to have similar efficacy and tolerability to that of vancomycin and standard anti-staphylococcal β-lactams plus vancomycin. In Phase II trials, there was a significant difference in eradication of MRSA between groups, ie, telavancin therapy 92% and standard therapy (vancomycin, nafcillin, oxacillin, or cloxacillin) 68% (P < 0.05). In Phase III trials, among clinically evaluable patients who had MRSA isolated at baseline, the overall therapeutic response was higher in patients treated with telavancin than in patients treated with vancomycin (89.9% versus 84.7%; 95% CI −0.3, 10.5). Also, the efficacy of telavancin was not inferior to that of vancomycin for the treatment of complicated skin and skin structure infections in the clinical trials.