Pharmacokinetics and safety of trovafloxacin in healthy male volunteers following administration of single intravenous doses of the prodrug, alatrofloxacin

Blue Light-Driven [4+2]-Cycloaddition: Diastereoselective Synthesis of Chromeno[4,3-b]quinoline and Chromeno[4,3-b][1,8]naphthyridine Scaffolds

A one-pot, metal-free, light-driven [4+2]-cycloaddition reaction is described by accessing a diverse collection of chromeno[4,3-b]quinoline and chromeno[4,3-b][1,8]naphthyridine scaffolds in a diastereoselective manner. This process delivered stereoisomers, which were challenging to produce by an inverse-demand Diels-Alder reaction. The tetracyclic products were provided in good yields, promoted by rose bengal and blue light in a single operation. The developed protocol proceeded efficiently without the need for expensive photosensitizers such as Ir or Ru complexes. The cascade is modular and step-economic, and the substrate scope is wide. Polycyclic architectures can be assembled from readily available aniline, aminoazine, indole, and salicylaldehyde derivatives.

The hepatotoxic fluoroquinolone trovafloxacin disturbs TNF- and LPS-induced p65 nuclear translocation in vivo and in vitro

Idiosyncratic drug-induced liver injury (IDILI) is a severe disease that cannot be detected during drug development. It has been shown that hepatotoxicity of some compounds associated with IDILI becomes apparent when these are combined in vivo and in vitro with LPS or TNF. Among these compounds trovafloxacin (TVX) induced apoptosis in the liver and increased pro-inflammatory cytokines in mice exposed to LPS/TNF. The hepatocyte survival and the cytokine release after TNF/LPS stimulation relies on a pulsatile activation of NF-κB. We set out to evaluate the dynamic activation of NF-κB in response to TVX + TNF or LPS models, both in mouse and human cells. Remarkably, TVX prolonged the first translocation of NF-κB induced by TNF both in vivo and in vitro. The prolonged p65 translocation caused by TVX was associated with an increased phosphorylation of IKK and MAPKs and accumulation of inhibitors of NF-κB such as IκBα and A20 in HepG2. Coherently, TVX suppressed further TNF-induced NF-κB translocations in HepG2 leading to decreased transcription of ICAM-1 and inhibitors of apoptosis. TVX prolonged LPS-induced NF-κB translocation in RAW264.7 macrophages increasing the secretion of TNF. In summary, this study presents new, relevant insights into the mechanism of TVX-induced liver injury underlining the resemblance between mouse and human models. In this study we convincingly show that regularly used toxicity models provide a coherent view of relevant pathways for IDILI. We propose that assessment of the kinetics of activation of NF-κB and MAPKs is an appropriate tool for the identification of hepatotoxic compounds during drug development.

Acyl-glucuronide as a Possible Cause of Trovafloxacin-Induced Liver Toxicity: Induction of Chemokine (C-X-C Motif) Ligand 2 by Trovafloxacin Acyl-glucuronide

Trovafloxacin is an antibiotic that was withdrawn from the market relatively soon after its release due to the risk of hepatotoxicity. Trovafloxacin is mainly metabolized to its acyl-glucuronide by uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) 1A1. In this study, we examined whether the acyl-glucuronide is involved in the development of hepatotoxicity. A UGT1A1-induced cell model was developed and the toxicity of trovafloxacin acyl-glucuronide was evaluated. The UGT1A1-induced cell model was developed by treating HepG2 cells with chrysin for 48 h. Chemokine (C-X-C motif) ligand 2, a cytokine involved in drug-induced liver injury, was uniquely induced by trovafloxacin in the UGT1A1-induced HepG2 cells. Induction of UGT1A1 resulted in a decrease in cell viability. An in vivo animal study further demonstrated the importance of UGT1A1 in the trovafloxacin-induced liver toxicity. Although the complete mechanism of trovafloxacin-induced liver injury is still unknown, trovafloxacin acyl-glucuronide can be involved in the development of toxic reactions in vitro and in vivo.

Pharmacokinetics and Pharmacodynamics of the New Quinolones

In this review, the authors describe the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of the new quinolones (levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin, and garenoxacin) and discuss their implications on adequate therapy of patients with respiratory infections. The newer quinolones display excellent bioavailability and have longer serum half-lives than ciprofloxacin. In addition, they have the ability to concentrate in respiratory tract tissues and fluids at levels that exceed serum-drug concentrations. Also, the newer quinolones exhibit broad-spectrum activity against both susceptible and resistant organisms. Those favorable PK/PD properties make the new quinolones an attractive therapeutic alternative to traditional agents for common respiratory infections. Understanding the PK/PD of quinolone antibiotics can facilitate selection of optimal regimens to hasten response, prevent treatment failures, and minimize the development of resistance.

Unexpected link between an antibiotic, pannexin channels and apoptosis

Plasma membrane pannexin 1 channels (PANX1) release nucleotide find-me signals from apoptotic cells to attract phagocytes. In a small molecule screen, we discovered the quinolone antibiotic trovafloxacin as a novel PANX1 inhibitor. Although quinolones are widely used to treat bacterial infections, some quinolones have unexplained side effects, including deaths among children. PANX1 is a direct target of trovafloxacin at drug concentrations seen in human plasma, and its inhibition led to dysregulated fragmentation of apoptotic cells. Genetic loss of PANX1 phenocopied trovafloxacin effects, revealing a non-redundant role for pannexin channels in regulating cellular disassembly during apoptosis. Increase in drug-resistant bacteria worldwide and the dearth of new antibiotics is a major human health challenge. Comparing different quinolone antibiotics suggests that certain structural features may contribute to PANX1 blockade. These data identify a novel linkage between an antibiotic, pannexin channels, and cellular integrity, and suggest that re-engineering certain quinolones might help develop newer antibacterials.

Molecular mechanisms of hepatocellular apoptosis induced by trovafloxacin-tumor necrosis factor-alpha interaction

Idiosyncratic drug-induced liver injury (IDILI) continues to be a significant human health problem. IDILI is characterized as occurring in a minority of individuals exposed to a drug, yet it accounts for as much as 17% of all cases of acute liver failure. Despite these concerns, the mechanisms underlying IDILI remain unknown. Trovafloxacin (TVX), which causes IDILI in humans, also causes hepatocellular death in vitro when combined with tumor necrosis factor-alpha (TNF) treatment. However, the molecular mechanisms involved in this toxicity are not fully characterized. The purpose of this study was to identify mechanisms by which TVX and TNF interact to cause hepatocellular death, with a focus on a human hepatocyte cell line. TVX and TNF interacted to cause cytotoxicity in HepG2 cells at drug concentrations similar to those in people undergoing TVX therapy. TVX/TNF treatment caused apoptosis and DNA damage in HepG2 cells that depended on caspase activation. Prolonged activation of JNK occurred in TVX/TNF-induced cytotoxicity, and treatment with the JNK selective inhibitor SP600125 attenuated cytotoxicity. TVX/TNF cotreatment also caused cytotoxicity in isolated primary murine hepatocytes that was dependent on caspase activation. These results increase understanding of molecular signaling pathways involved in hepatocellular death caused by a drug with idiosyncratic liability in the presence of TNF.

Fluoroquinolone disposition: identification of the contribution of renal secretory and reabsorptive drug transporters

INTRODUCTION

Fluoroquinolones (FQs) exist as charged molecules in blood and urine making their absorption, distribution, and elimination likely to be influenced by active transport mechanisms. Greater understanding of in vivo FQ clearance mechanisms should help improve the predictability of drug-drug interactions, enhance the clinical safety and efficacy, and aid future novel drug design strategies.

AREAS COVERED

The authors present an overview of FQ development and associated drug-drug interactions, followed by systematic quantitative review of the physicochemical and in vivo pharmacokinetic properties for 15 representative FQs using historical clinical literature. These results were correlated with in vitro studies implicating drug transporters in FQ clearance to link clinical and in vitro evidence supporting the contribution of drug transport mechanisms to FQ disposition. Specific transporters likely to handle FQs in human renal proximal tubule cells are also identified.

EXPERT OPINION

Renal handling, that is, tubular secretion and reabsorption, appears to be the main determinant of FQ plasma half-life, clinical duration of action, and drug-drug interactions. Due to their zwitterionic nature, FQs are likely to interact with organic anion and cation transporters within the solute carrier (SLC) superfamily, including OAT1, OAT3, OCT2, OCTN1, OCTN2, MATE1, and MATE2. The ATP-binding cassette (ABC) transporters MDR1, MRP2, MRP4, and BCRP also may interact with FQs.

Relationship of quantitative structure and pharmacokinetics in fluoroquinolone antibacterials

AIM: To study the relationship between quantitative structure and pharmacokinetics (QSPkR) of fluoroquinolone antibacterials.

METHODS: The pharmacokinetic (PK) parameters of oral fluoroquinolones were collected from the litera-ture. These pharmacokinetic data were averaged, 19 compounds were used as the training set, and 3 served as the test set. Genetic function approximation (GFA) module of Cerius² software was used in QSPkR analysis.

RESULTS: A small volume and large polarizability and surface area of substituents at C-7 contribute to a large area under the curve (AUC) for fluoroquinolones. Large polarizability and small volume of substituents at N-1 contribute to a long half life elimination.

CONCLUSION: QSPkR models can contribute to some fluoroquinolones antibacterials with excellent pharmacokinetic properties.

Effect of ethanol on fluoroquinolone efficacy in a rat model of pneumococcal pneumonia

This investigation compared the effect of ethanol on fluoroquinolone antibiotic efficacy and pharmacodynamics in an ethanol-fed rat model of pneumococcal pneumonia. Male Sprague-Dawley rats received a liquid diet containing 36% of total calories as ethanol. Paired controls (pair-fed controls) were fed a liquid diet without ethanol or received rat chow. Diets began 7 days before and continued for 10 days after transtracheal infections with 10 times the 50% lethal dose of type 3 Streptococcus pneumoniae. Beginning 18 h after infection, the rats received once daily subcutaneous phosphate-buffered saline, levofloxacin, moxifloxacin, or trovafloxacin at 50 or 100 mg/kg of body weight. White blood cell counts were determined, blood samples were collected for culture, and mortality was recorded. Additional rats were killed on day 5 for pharmacodynamic studies and quantitative cultures of bronchoalveolar lavage fluid. Bacteremia occurred by day 3 in 20 of 22 untreated rats. All 22 untreated rats died by day 9. Moxifloxacin treatment was effective in all diet groups at both the 50- and 100-mg/kg doses. In contrast, 50-mg/kg doses of levofloxacin and trovafloxacin improved survival in ethanol-fed rats but were ineffective in chow-fed rats. High-dose trovafloxacin at 100 mg/kg was associated with increased mortality in pair-fed rats. The free-fraction area under the concentration-time curve/MIC ratio exceeded 50 with all antibiotics in the ethanol group but dropped below 30 with levofloxacin and trovafloxacin in the pair- and chow-fed rats, with higher mortality. Achievement of adequate antibiotic-free fraction area under the concentration-time curve/MIC ratios helps overcome ethanol-induced immune defects induced in experimental pneumococcal pneumonia.

Serum bactericidal activity of trovafloxacin, in combination with cefepime or amikacin, in healthy volunteers

OBJECTIVE

To investigate the phamacokinetics and serum bactericidal activities (SBAs) of trovafloxacin, cefepime and amikacin alone and trovafloxacin in combination with cefepime or amikacin, so that the most favorable combination with trovafloxacin can be determined.

METHODS

In this open, randomized, crossover study, 12 healthy volunteers (six females, six males; mean age +/- SD, 25.1 +/- 2.6 years) received an infusion of either 300 mg of alatrovafloxacin or 2000 mg of cefepime or 6 mg/kg body weight amikacin alone, or 300 mg of alatrovafloxacin plus 2000 mg of cefepime or plus 6 mg/kg body weight amikacin. The SBAs against Pseudomonas aeruginosa, Staphylococcus aureus (11 strains each), Citrobacter freundii and Acinetobacter spp. (10 strains each) 1, 10 and 24 h after drug administration were measured by a standard microdilution method. Concentrations of trovafloxacin, cefepime and amikacin in serum and urine were analyzed before and up to 10 and 12 h, respectively, after drug infusion.

RESULTS

Significant synergistic effects on SBA were observed with the combination of trovafloxacin and cefepime against P. aeruginosa, S. aureus and Acinetobacter spp. 1 h after drug administration, and against Citrobacter freundii 1, 10 and 24 h after drug administration. The combination of trovafloxacin and amikacin showed significant synergistic effects against P. aeruginosa, S. aureus and C. freundii 1 h after drug administration. The combination of trovafloxacin and cefepime was, in general, more active than the combination of trovafloxacin and amikacin. No significant differences in the serum concentrations of trovafloxacin were observed between single and combined administration. However, the maximal concentration of cefepime was significantly lower when it was used in combination with trovafloxacin.

CONCLUSION

Our study suggests a favorable interaction between trovafloxacin and cefepime. This combination showed more synergistic bactericidal activity against most of the test strains compared to the combination of trovafloxacin and amikacin. However, for P. aeruginosa, the bactericidal activity of cepefime alone was higher than that of the combination with trovafloxacin.

Comparative in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae

STUDY OBJECTIVE

To compare in vitro activity and pharmacodynamics of five fluoroquinolones against clinical isolates of Streptococcus pneumoniae.

DESIGN

In vitro analysis.

SETTING

University research laboratory.

INTERVENTION

Minimum inhibitory concentrations (MICs) were determined for penicillin and five fluoroquinolones by E test for 201 S. pneumoniae isolates. Serum concentration-time profiles were simulated for the following regimens: ciprofloxacin 750 mg orally every 12 hours and 400 mg intravenously every 8 hours; levofloxacin 500 mg orally and intravenously every 24 hours; trovafloxacin 200 mg orally and intravenously every 24 hours; gatifloxacin 400 mg orally and intravenously every 24 hours; and clinafloxacin 200 mg orally and intravenously every 12 hours.

MEASUREMENTS AND MAIN RESULTS

Free 24-hour areas under the serum concentration-time curves (AUC0-24) were calculated using the trapezoidal rule, and the average AUC0-24:MIC ratio was calculated for each regimen. Differences in ratios among agents were determined by analysis of variance (Scheffe post hoc test, p < 0.05). For intravenous dosing, the average AUC0-24:MIC for gatifloxacin, clinafloxacin, trovafloxacin, ciprofloxacin, and levofloxacin was 146, 142, 122, 71, and 61, respectively. For both oral and intravenous regimens, gatifloxacin and clinafloxacin ratios were significantly greater than those for trovafloxacin, levofloxacin, and ciprofloxacin (p < or = 0.007). Ratios for trovafloxacin were significantly greater than those for levofloxacin and ciprofloxacin (p < 0.0001), and levofloxacin and ciprofloxacin ratios were not significantly different from each other.

CONCLUSION

Gatifloxacin and clinafloxacin achieve significantly higher AUC0-24:MIC ratios for S. pneumoniae than trovafloxacin, levofloxacin, and ciprofloxacin. Large comparative studies are necessary to determine the clinical significance of these findings.

A dose-escalation study of the safety, tolerability, and pharmacokinetics of intravenous gatifloxacin in healthy adult men

STUDY OBJECTIVES

To examine single- and multiple-dose safety, tolerability, and pharmacokinetics of gatifloxacin administered as daily 1-hour intravenous infusions for 14 days, and to determine the effect of gatifloxacin on glucose tolerance, pancreatic beta-cell function, and electrocardiogram (ECG).

DESIGN

Randomized, double-blind, placebo-controlled, ascending-dose study.

SETTING

Bristol-Myers Squibb, Clinical Pharmacology Unit, Princeton, New Jersey, USA.

PATIENTS

Forty healthy male subjects, eight in each of five groups, were enrolled to receive sequential doses of gatifloxacin: 200 mg (10 mg/ml), 200 mg (1 mg/ml), and 400, 600, and 800 mg (2 mg/ml); six subjects per group received active drug and two received placebo.

INTERVENTIONS

A single dose of the drug was administered as an intravenous infusion over 1 hour. After a 72-hour washout period, the drug was administered once/day for 14 days by 1-hour intravenous infusion. Physical examinations, ECGs, spirometry, and clinical laboratory tests, including glucose tolerance test (GTT) and assessment of glucose homeostasis, were performed before treatment and on selected dosing days. A safety evaluation was performed before escalating doses. No intrasubject dose escalation was permitted.

MEASUREMENTS AND MAIN RESULTS

The pharmacokinetics of gatifloxacin were dose linear and time independent after intravenous administration over the range of 200-800 mg. After daily repeated administration, a predictable, modest accumulation was observed; steady state was reached by the third dose. Approximately 80% of the dose was recovered as unchanged drug in urine. Mean changes (before the first dose to the last dose) after oral GTT and in fasting serum glucose, insulin, and C-peptide concentrations were comparable among the gatifloxacin and placebo treatment groups. A mild, transient decrease in serum glucose was associated with the end of the 1-hour infusion of gatifloxacin. No clinically important changes in QTc interval or spirometry occurred. The most frequent treatment-related adverse effects were local intravenous site reactions, which were associated with dose and/or concentration of intravenous solution.

CONCLUSION

Gatifloxacin was safe and well tolerated at intravenous doses of up to 800 mg/day for 14 days. Gatifloxacin pharmacokinetics were linear and time independent.

Activities of trovafloxacin and ampicillin-sulbactam alone or in combination versus three strains of vancomycin- intermediate Staphylococcus aureus in an in vitro pharmacodynamic infection model

The recent isolation of clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) with intermediate susceptibility (MICs, 8 microg/ml) to vancomycin (vancomycin-intermediate S. aureus [VISA]) emphasizes the importance of developing novel antimicrobial regimens and/or agents for future treatment. We studied the activities of ampicillin-sulbactam and trovafloxacin alone or in combination against three unique strains of VISA in an in vitro infection model. Two VISA strains were trovafloxacin susceptible (MICs, < or =2 microg/ml); one VISA strain was trovafloxacin resistant (MIC, 4 microg/ml). Trovafloxacin was administered to simulate a dose of 200 or 400 mg every 24 h. Ampicillin-sulbactam was administered to simulate a dose of 3 g every 6 h. Samples were removed from the infection models over 48 h, and reductions in colony counts were compared between regimens. Trovafloxacin (200 mg) produced rapid killing of a control MRSA strain over the 48-h experiment but produced only slight killing of all three VISA strains. The higher dose of trovafloxacin improved killing but did not produce bactericidal activity at 48 h. Ampicillin-sulbactam produced rapid bactericidal activity against all four strains tested, and colony counts at 8 h were at the limits of detection. However, regrowth occurred by 48 h for each strain. The combination of ampicillin-sulbactam and trovafloxacin provided additive activity against two of the three VISA strains. In conclusion, trovafloxacin or ampicillin-sulbactam alone did not provide adequate activity against the VISA strains for the 48-h evaluation period, but the combination could help improve activity against some strains of VISA.

Pharmacokinetics of a fluoronaphthyridone, trovafloxacin (CP 99,219), in infants and children following administration of a single intravenous dose of alatrofloxacin

The pharmacokinetics of trovafloxacin following administration of a single intravenous dose of alatrofloxacin, equivalent to 4 mg of trovafloxacin per kg of body weight, were determined in 6 infants (ages 3 to 12 months) and 14 children (ages, 2 to 12 years). There was rapid conversion of alatrofloxacin to trovafloxacin, with an average +/- standard deviation (SD) peak trovafloxacin concentration determined at the end of the infusion of 4.3 +/- 1.4 microg/ml. The primary pharmacokinetic parameters (average +/- SD) analyzed were volume of distribution at steady state (1.6 +/- 0.6 liters/kg), clearance (151 +/- 82 ml/h/kg), and half-life (9.8 +/- 2.9 h). The drug was well tolerated by all children. There were no age-related differences in any of the pharmacokinetic parameters studied. Less than 5% of the administered dose was excreted in the urine over 24 h. On the basis of the mean area under the concentration-time curve of 30.5 +/- 10.1 microg. h/ml and the susceptibility (< or =0.5 microg/ml) of common pediatric bacterial pathogens to trovafloxacin, dosing of 4 mg/kg/day once or twice daily should be appropriate.

Pharmacokinetics of intravenous trovafloxacin in critically ill adults

The pharmacokinetic disposition of numerous antimicrobial agents is altered in critically ill patients. Pharmacokinetics of trovafloxacin, a fluoroquinolone indicated specifically for severe, life-threatening infections in the intensive care unit, have not been well studied in this population. We characterized the pharmacokinetic disposition of trovafloxacin after administration of alatrofloxacin, the intravenous prodrug, in critically ill adults. Seven patients (3 men, 4 women; mean +/- SD age 59.4 +/- 20.6 yrs; baseline aspartate aminotransferase [AST]/alanine aminotransferase [ALT] 66.0 +/- 40.6/51.5 +/-37.5 IU/L; median Acute Physiology and Chronic Health Evaluation [APACHE II] score 27, range 15-32) were studied at estimated steady state. Calculated (mean +/- SD) half-life, clearance at steady state, and volume of distribution in all patients were 10.9 +/- 1.8 hours, 161.3 +/- 41.1 ml/minute, and 1.4 +/- 0.4 L/kg. In patients receiving 300 mg, maximum concentration, minimum concentration, and area under the curve from 0-24 hours were 3.6 +/- 0.5 mg/L, 0.6 +/- 0.3 mg/L, and 34.2 +/- 10.6 mg x hr/L, respectively. These results are consistent with published values in other patient populations, indicating that trovafloxacin pharmacokinetics are not substantially altered in critically ill patients with normal or mildly impaired hepatic function.

Comparison of the fluoroquinolones based on pharmacokinetic and pharmacodynamic parameters

Assessment of pharmacodynamic activity from standard in vitro minimum inhibitory concentrations (MICs) alone is insufficient to predict in vivo potency. Achievable serum and tissue concentrations as well as pharmacokinetic characteristics must be considered. When pharmacokinetic and pharmacodynamic values are combined, the area under the inhibitory curve (AUIC) and peak concentration:MIC ratio predict clinical cure for fluoroquinolones. Clinical data and animal models indicate that a peak:MIC of 10:1 and above and an AUIC of 125 and above are predictive of a clinical cure for this class of antimicrobials against gram-negative organisms. The values may be used to compare and contrast fluoroquinolones to determine which would be best for treating a specific microorganism. Pharmacodynamic data also can be used to design regimens that minimize the risk of suboptimal drug levels. Ensuring the optimal fluoroquinolone dosage based on pharmacodynamic principles would diminish the emergence of resistant organisms and prevent treatment failures.

Treatment of experimental staphylococcal endocarditis due to a strain with reduced susceptibility in vitro to vancomycin: efficacy of ampicillin-sulbactam

We evaluated several 3-day antimicrobial regimens in the treatment of experimental endocarditis caused by an oxacillin-resistant Staphylococcus aureus strain exhibiting intermediate susceptibility in vitro to vancomycin (VISA). Neither vancomycin alone nor trovafloxacin exhibited in vivo efficacy; addition of amikacin to vancomycin yielded a modest in vivo effect. In contrast, the combination of ampicillin and sulbactam was highly effective in vivo, causing a mean decrease in VISA vegetation densities of >5 log(10) CFU/g versus those of untreated controls.

Comparative efficacies of antibiotics in a rat model of meningoencephalitis due to Listeria monocytogenes

The antibacterial activities of amoxicillin-gentamicin, trovafloxacin, trimethoprim-sulfamethoxazole (TMP-SMX) and the combination of trovafloxacin with TMP-SMX were compared in a model of meningoencephalitis due to Listeria monocytogenes in infant rats. At 22 h after intracisternal infection, the cerebrospinal fluid was cultured to document meningitis, and the treatment was started. Treatment was instituted for 48 h, and efficacy was evaluated 24 h after administration of the last dose. All tested treatment regimens exhibited significant activities in brain, liver, and blood compared to infected rats receiving saline (P < 0.001). In the brain, amoxicillin plus gentamicin was more active than all of the other regimens, and trovafloxacin was more active than TMP-SMX (bacterial titers of 4.1 +/- 0.5 log10 CFU/ml for amoxicillin-gentamicin, 5.0 +/- 0.4 log10 CFU/ml for trovafloxacin, and 5.8 +/- 0.5 log10 CFU/ml for TMP-SMX; P < 0.05). In liver, amoxicillin-gentamicin and trovafloxacin were similarly active (2.8 +/- 0.8 and 2.7 +/- 0.8 log10 CFU/ml, respectively) but more active than TMP-SMX (4.4 +/- 0. 6 log10 CFU/ml; P < 0.05). The combination of trovafloxacin with TMP-SMX did not alter the antibacterial effect in the brain, but it did reduce the effect of trovafloxacin in the liver. Amoxicillin-gentamicin was the most active therapy in this study, but the activity of trovafloxacin suggests that further studies with this drug for the treatment of Listeria infections may be warranted.

A randomized, crossover design study of the pharmacology of extended-spectrum fluoroquinolones for pneumococcal infections

STUDY OBJECTIVES

The objectives of this study were to characterize the single-dose and steady-state plasma pharmacokinetics of IV levofloxacin and IV alatrofloxacin, and to compare the results to pneumococcal isolate sensitivities in order to estimate the clinical efficacy of current community-acquired pneumonia treatment regimens against pneumococcal infections.

DESIGN

Two-way, open-label, randomized, crossover study.

PARTICIPANTS

Each of 12 healthy volunteer subjects received IV levofloxacin, 500 mg qd for 7 days, and IV alatrofloxacin, 200 mg qd for 7 days. The two regimens were separated by a 2-week washout period.

MEASUREMENTS AND RESULTS

Plasma concentration profiles were collected around the first and final doses of both regimens and were assayed for their respective quinolone concentrations. When the peak concentrations for both agents were compared to standard twofold dilution minimum inhibitory concentration (MIC) values for pneumococcal isolates, it was discovered that the breakpoint MIC value at which each compound would no longer achieve a peak plasma concentration/MIC ratio of at least 12:1 was 0.5 mg/L for levofloxacin and 0.25 mg/L for alatrofloxacin.

CONCLUSIONS

Based on the MIC that inhibits 90% of isolates of Streptococcus pneumoniae for both of these agents (1.0 to 2.0 mg/L for levofloxacin and 0.125 to 0.25 mg/L for trovafloxacin), our results indicate that although the once-daily regimen of alatrofloxacin appears to be appropriate for this pathogen, a more aggressive regimen may need to be investigated to optimize the clinical and microbiological effects of levofloxacin.

Pharmacodynamics of trovafloxacin in a mouse model of cephalosporin-resistant Streptococcus pneumoniae pneumonia

Trovafloxacin is a potentially useful agent for treatment of infections caused by cephalosporin-resistant Streptococcus pneumoniae. We studied the effectiveness of trovafloxacin therapy and examined the correlation between pharmacodynamic indices in serum and lung, and bacterial killing. Immunocompetent Balb/c mice were infected by intranasal inoculation of a cephalosporin-resistant S. pneumoniae isolate (MIC of ceftriaxone and trovafloxacin 2 and 0.06 mg/L, respectively). Trovafloxacin 10-30 mg/kg/day in one or three divided doses was started 15 h after infection. Serum and lung drug concentrations were measured at multiple time points for 24 h. Serum concentrations peaked at 30-60 min and lung concentrations approximately 30 min later. The serum T1/2 was approximately 9 h and lung T1/2 varied from 5 to 9 h. Lung AUC and Cmax values were 2-3 times greater than those in serum. At the start of therapy lung bacterial concentrations were 8.4 +/- 0.3 log10 cfu/mL and 24 h later had decreased by 3.5 +/- 0.2, 4.0 +/- 0.2, 0.8 +/- 0.3 and 1.0 +/- 1.2 log10 cfu/mL with 30 mg/kg x 1, 10 mg/kg x 3, 10 mg/kg x 1 and 3.3 mg/kg x 3 regimens, respectively. Although the larger dosages were more effective (P < 0.001) the differences between divided and single dosage regimens were not significant. Trovafloxacin serum AUC/MIC ratio correlated best with bacterial killing in the lungs over 24 h. Trovafloxacin is likely to be useful in the treatment of cephalosporin-resistant S. pneumoniae pneumonia.

The new fluoroquinolones: A critical review

OBJECTIVE

This paper reviews the literature available on the new fluoroquinolones - clinafloxacin, gatifloxacin, grepafloxacin, levofloxacin, moxifloxacin, sparfloxacin and trovafloxacin - to compare these agents with each other and contrast them with ciprofloxacin, an older fluoroquinolone.

DATA SELECTION

Published papers used were obtained by searching MEDLINE for articles published between 1994 and 1998, inclusive. References of published papers were also obtained and reviewed. Abstracts from scientific proceedings were reviewed.

DATA EXTRACTION

Due to the limited data available on several of the agents, criteria for study inclusion in the in vitro, pharmacokinetics and in vivo sections were not restrictive.

DATA SYNTHESIS

The new fluoroquinolones offer excellent Gram-negative bacillary activity and improved Gram-positive activity (eg, against Streptococcus pneumoniae and Staphylococcus aureus) over ciprofloxacin. Clinafloxacin, gatifloxacin, moxifloxacin, sparfloxacin and trovafloxacin display improved activity against anaerobes (eg, Bacteriodes fragilis). All of the new fluoroquinolones have a longer serum half-life than ciprofloxacin (allowing for once daily dosing), and several are eliminated predominantly by nonrenal means. No clinical trials are available comparing the new fluoroquinolones with each other. Clinical trials comparing the new fluoroquinolones with standard therapy have demonstrated good efficacy in a variety of infections. Their adverse effect profile is similar to that of ciprofloxacin. Clinafloxacin and sparfloxacin cause a high incidence of phototoxicity (1.5% to 14% and 2% to 11.7%, respectively), grepafloxacin causes a high incidence of taste perversion (9% to 17%) and trovafloxacin causes a high incidence of dizziness (11%). They all interact with metal ion-containing drugs (eg, antacids), and clinafloxacin and grepafloxacin interact with theophylline. The new fluoroquinolones are expensive; however, their use may result in savings in situations where, because of their potent and broad spectrum of activity, they can be used orally in place of intravenous antibiotics.

CONCLUSIONS

The new fluoroquinolones offer advantages over ciprofloxacin in terms of improved in vitro activity and pharmacokinetics. Whether these advantages translate into improved clinical outcomes is presently unknown. The new fluoroquinolones have the potential to emerge as important therapeutic agents in the treatment of respiratory tract and genitourinary tract infections.

Evaluation of bactericidal activities of LY333328, vancomycin, teicoplanin, ampicillin-sulbactam, trovafloxacin, and RP59500 alone or in combination with rifampin or gentamicin against different strains of vancomycin-intermediate Staphylococcus aureus by time-kill curve methods

This in vitro study evaluated the activities of vancomycin, LY333328, and teicoplanin alone and in combination with gentamicin, rifampin, and RP59500 against Staphylococcus aureus isolates with intermediate susceptibilities to vancomycin. Ampicillin-sulbactam and trovafloxacin were also evaluated. LY333328 and ampicillin-sulbactam resulted in bactericidal activity against all isolates. The combination of gentamicin with glycopeptides showed synergistic activity, while rifampin had no added benefit.

Trovafloxacin: an overview

Trovafloxacin, a new synthetic naphthyridine fluoroquinolone antibiotic, is a broad-spectrum agent available orally and intravenously. It was recently approved by the Food and Drug Administration for the treatment of selected pulmonary, surgical, intraabdominal, gynecologic, pelvic, skin, and urinary tract infections. Its spectrum of activity includes aerobic gram-positive and gram-negative organisms as well as anaerobic pathogens. It is rapidly absorbed after oral administration, achieves good tissue and cerebrospinal fluid penetration, and has a half-life that allows once-daily dosing. It is hepatically metabolized, and dosage adjustments are necessary for patients with severe hepatic dysfunction but not for those with mild or moderate dysfunction or renal dysfunction. The drug has a favorable safety profile, and a high tendency for transient first-dose dizziness and/or lightheadedness in young women. Similar to other quinolones, trovafloxacin should not be taken with antacids that contain aluminum or magnesium, sucralfate, or ferrous sulfate. Trovafloxacin may prove beneficial as it allows for oral or intravenous monotherapy against indicated infections that normally require multidrug, broad-spectrum antibiotic coverage.

Trovafloxacin: a new fluoroquinolone

OBJECTIVE

To review the pharmacology, antimicrobial activity, pharmacokinetics, clinical efficacy, and safety of trovafloxacin.

DATA SOURCES

A MEDLINE search (January 1966-April 1998) was conducted for relevant literature using the terms CP-99,219, CP-116,519, trovafloxacin, and alatrofloxacin. Abstracts published by the American Society of Microbiology during 1995-1997 meetings were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

All in vitro, animal, and human studies were reviewed for the antimicrobial activity, pharmacokinetics, efficacy, and safety of trovafloxacin.

DATA SYNTHESIS

Trovafloxacin is a new fluoroquinolone with enhanced activity against gram-positive and anaerobic microorganisms. The oral bioavailability under fasting conditions is approximately 88%. The elimination half-life of trovafloxacin is approximately 10 hours. Less than 10% of trovafloxacin is eliminated unchanged in the urine. Trovafloxacin is effective in the treatment of community-acquired pneumonia and nosocomial pneumonia with cure rates of > 90% and 77%, respectively. Trovafloxacin is comparable with ceftriaxone in the treatment of meningococcal meningitis in children; each produces a cure rate of approximately 90%. In treatment of uncomplicated urinary tract infection, both ciprofloxacin and trovafloxacin achieve an eradication rate of > or = 93%. Trovafloxacin is similar to ofloxacin in the treatment of urogenital Chlamydia trachomatis and acute exacerbations of chronic bronchitis, with clinical success in 97% of patients with each drug. The common adverse effects of trovafloxacin include dizziness, headache, and gastrointestinal intolerance.

CONCLUSIONS

The advantages of once-daily dosing and enhanced activity of trovafloxacin against gram-positive and anaerobic organisms may expand its use over available fluoroquinolones. Further studies are needed to define its role in the treatment of various infectious diseases.

In vitro activity of trovafloxacin against ciprofloxacin-susceptible and -resistant clinical bacterial isolates and assessment of the trovafloxacin disk test

A total of 4241 consecutive clinical bacterial isolates from 10 North American medical centers were tested for susceptibility to trovafloxacin. Trovafloxacin was significantly more active than ciprofloxacin against Gram-positive bacteria, Acinetobacter spp., and Stenotrophomonas maltophilia, and resistance to trovafloxacin occurred in these groups only among isolates with high-level resistance (MIC > or = 16 micrograms/mL) to ciprofloxacin. With other species, the two drugs had comparable activity. Concerns about staphylococci and Pseudomonas aeruginosa with trovafloxacin MICs of 2.0 micrograms/mL (the upper end of the susceptible category) are discussed. Results of trovafloxacin disk diffusion test on more than 3200 nonfastidious isolates supported the FDA-approved zone size interpretive criteria when the MIC breakpoint of < or = 2.0 micrograms/mL is used to define the trovafloxacin-susceptible category.

Safety and tolerability of intravenous-to-oral treatment and single-dose intravenous or oral prophylaxis with trovafloxacin

BACKGROUND

The new fourth-generation fluoroquinolone, trovafloxacin, is active in vitro against gram-positive and gram-negative organisms, atypical pathogens, and anaerobes, and has pharmacokinetics permitting once-daily intravenous or oral dosing. Safety/tolerability data from phase II/III clinical trials of sequential intravenous alatrofloxacin to oral trovafloxacin and single-dose intravenous or oral prophylaxis are summarized.

METHODS

All trials were double-blind, randomized, and multicenter. In multidose trials with alatrofloxacin, 1,257 patients requiring initial intravenous therapy received once-daily alatrofloxacin (trovafloxacin prodrug, 200 or 300 mg/day) followed by oral 200 mg/day trovafloxacin. An additional 444 patients received a single alatrofloxacin or trovafloxacin dose prophylactically for surgical procedures.

RESULTS

Therapy with alatrofloxacin was well tolerated. The most common treatment-related adverse events in studies of intravenous alatrofloxacin followed by oral trovafloxacin were nausea, headache, insertion site reaction, and dizziness. In single-dose intravenous or oral prophylaxis studies, insertion-site reaction, pruritus, and insertion-site pain were the most common treatment-related adverse events. No serious quinolone toxicity or drug interactions were reported. The incidence of serious treatment-related adverse events was < 1% in both the alatrofloxacin and comparator groups. In comparative trials, mortality due to all causes after trovafloxacin was similar to that after comparative agents; there was no mortality related to trovafloxacin administration.

CONCLUSION

In this large patient sample, intravenous alatrofloxacin followed by oral trovafloxacin was safe and well tolerated. Serious adverse events, such as phototoxicity, cardiovascular toxicity, and hemolytic anemia associated with older fluoroquinolones, were not noted with trovafloxacin. No interactions of trovafloxacin with other drugs were reported. The safety and tolerability of trovafloxacin, along with in vitro activity against key pathogens and pharmacokinetics permitting once-daily administration, support its oral and intravenous use in patients with obstetric, gynecologic, and intra-abdominal infections as well as for prophylaxis of surgical infection.

Pharmacodynamics and microbiology of trovafloxacin in animal models of surgical infection

Trovafloxacin provides broad in vitro and in vivo coverage of the aerobic and anaerobic pathogens found frequently in surgical infections. In vitro susceptibility testing indicated that trovafloxacin inhibited gram-positive staphylococci and enterococci, numerous gram-negative organisms, including Escherichia coli, and anaerobic pathogens, such as Bacteroides fragilis. Trovafloxacin protected mice from lethal infections induced by gram-negative or gram-positive organisms, even when these organisms were inoculated in combination with B. fragilis. Trovafloxacin protected rats in models of intra-abdominal sepsis induced by inoculation with E. coli and B. fragilis or with multiple aerobic and anaerobic pathogens. In these experimental models, trovafloxacin protected rats from lethal infection, reduced intra-abdominal abscess formation, and inhibited bacterial growth. Drug concentrations were greater in intra-abdominal abscesses than in serum, reflecting the good tissue penetration of trovafloxacin. These results indicate that trovafloxacin may be effective in prophylaxis and treatment of mixed infections in surgical patients.

Overview of quinolones in the treatment and prevention of surgical infection

Postoperative infection remains a complication of surgical procedures, resulting in increased morbidity, mortality, and cost. The frequent polymicrobial etiology and emerging patterns of resistance continue to compromise cure rates. Although quinolones have many attractive properties for the surgical setting, combination therapy is routinely indicated for appropriate coverage. Advanced-generation quinolones, such as trovafloxacin, offer an increased antimicrobial spectrum, including activity against important surgical pathogens, and longer elimination half-lives. These newer agents may be used intravenously or orally as once-daily single-agent therapy for surgical prophylaxis, and in place of combination therapy for complex intra-abdominal and pelvic infections.

The bioavailability of nasogastric versus tablet-form oral trovafloxacin in healthy subjects

BACKGROUND

Patients in the hospital, as well as those in home care settings, often require nutritional supplementation with enteral feeding solutions. In addition, patients with serious infections who are clinically unstable often cannot maintain adequate intake by mouth and may require an alternative to oral antibiotic administration. However, delivery of crushed oral formulations of drugs via nasogastric tubes is often carried out without adequate bioavailability data, and this method of administration may not always be equivalent to oral drug delivery.

METHODS

In an open-label, randomized, four-period, four-treatment, cross-over study, 24 healthy volunteers were given one dose of each of the following treatments, with a 7-day wash-out between dosing periods: Treatment A: two 100-mg trovafloxacin tablets given orally with 240 mL water; Treatment B: two crushed 100-mg trovafloxacin tablets suspended in water and administered through a nasogastric tube into the stomach; Treatment C: two crushed 100-mg trovafloxacin tablets suspended in water and administered through a nasogastric tube into the duodenum; or Treatment D: two crushed 100-mg trovafloxacin tablets suspended in water and given through a nasogastric tube into the stomach concomitantly with an enteral feeding solution (240 mL full-strength Osmolite).

RESULTS

Pharmacokinetic analyses showed that the bioavailability of trovafloxacin after administration of crushed tablets into the stomach with or without concomitant enteral feeding was not significantly different from that of the orally administered whole tablets: the 90% confidence limits of the area under the concentration-time curve (AUC(0-infinity)) for Treatment B versus Treatment A (91.3%, 109.5%) and Treatment D versus Treatment A (91.6%, 109.9%) were well within the bioequivalence criteria of 80% to 125%. Results of analysis of variance (ANOVA) indicated no significant sequence, period, or treatment-by-period interaction effects. Administration of trovafloxacin into the duodenum (Treatment C) resulted in reduced systemic exposure to trovafloxacin, with a 31% decrease in AUC(0-infinity) and a 30% decrease in peak serum concentration (Cmax) compared to oral administration. Time to peak serum concentration (Tmax) was 1.7 hours after oral administration of trovafloxacin and 1.1 hours after administration directly into the stomach or duodenum through a nasogastric tube in the absence of concomitant enteral feeding. All four treatments were well tolerated; no participant discontinued the study due to adverse events and no serious adverse events were reported.

CONCLUSIONS

These results showed that administration of crushed trovafloxacin tablets through a nasogastric tube into the stomach, with or without concomitant enteral feeding, achieves absorption and tolerability comparable to those of orally administered trovafloxacin tablets.

Treatment of acute gynecologic infections with trovafloxacin. Trovafloxacin Surgical Group

BACKGROUND

Trovafloxacin, a broad-spectrum fourth-generation quinolone with gram-positive and gram-negative aerobic and anaerobic bacterial activity, is available in oral and intravenous formulations. The objective of this prospective, multicenter, double-blind, randomized study was to compare the efficacy of trovafloxacin with that of cefoxitin, an approved drug for treatment of acute gynecologic infections, together with amoxicillin/clavulanic acid as oral follow-on treatment.

METHODS

Patients with a clinical diagnosis of acute pelvic infection received either intravenous alatrofloxacin with oral trovafloxacin follow-on (trovafloxacin) or a combined regimen of cefoxitin followed by amoxicillin/clavulanic acid for a maximum of 14 days. The primary endpoint was clinical response to therapy on follow-up at day 30.

RESULTS

Clinical success rates were comparable between the trovafloxacin (n = 107) and comparative (n = 119) groups at study end (90% vs. 86%, respectively; 95% confidence interval, -4.5, 12.5). Among clinically evaluable patients, clinical success rates for infections involving Enterococcus species were higher with trovafloxacin than with the comparative regimen at the end of treatment (96% and 85%) and at study end (96% and 86%).

CONCLUSION

Intravenous alatrofloxacin followed by oral trovafloxacin for a maximum of 14 days of total therapy was efficacious in the treatment of acute pelvic infections.

Trovafloxacin in the treatment of intra-abdominal infections: results of a double-blind, multicenter comparison with imipenem/cilastatin. Trovafloxacin Surgical Group

BACKGROUND

Trovafloxacin, a new broad-spectrum fourth-generation quinolone, has in vitro activity against most gram-negative and gram-positive anaerobes and aerobes. Trovafloxacin is available as both an intravenous formulation, alatrofloxacin, and a single daily oral tablet. Excellent tissue pharmacokinetics and oral bioavailability suggest usefulness in the treatment of complicated intra-abdominal infections. Thus, the efficacy of alatrofloxacin followed by oral trovafloxacin was compared with the standard regimen of intravenous imipenem/cilastatin followed by oral amoxicillin/clavulanic acid in this prospective, multicenter, double-blind trial.

METHODS

Patients were randomized to receive either 300 mg alatrofloxacin daily followed by 200 mg oral trovafloxacin daily or 1 g imipenem/cilastatin intravenously thrice daily followed by 500 mg oral amoxicillin/clavulanic acid thrice daily for up to 14 days following surgical intervention of a documented intra-abdominal infection. Efficacy was assessed at the end of therapy and at follow-up (day 30).

RESULTS

At the end of the study, cure or improvement occurred in 83% (129/156) and 84% (127/152) of clinically evaluable patients in the trovafloxacin and comparative groups, respectively. Pathogen eradication rates, adverse-event profiles, and significant laboratory abnormalities were comparable between groups.

CONCLUSION

Intravenous alatrofloxacin with or without oral trovafloxacin was as effective as intravenous imipenem/cilastatin followed by oral amoxicillin/clavulanic acid in complicated intra-abdominal infections.

Penetration of trovafloxacin into gynecologic tissues

BACKGROUND

This randomized open-label study assessed the penetration into gynecologic tissues of trovafloxacin, a new broad-spectrum, fourth-generation fluoroquinolone with in vitro activity against anaerobes, gram-positive, gram-negative, and atypical pathogens.

METHODS

Women undergoing hysterectomy or hysterectomy and adnexectomy received 200 mg trovafloxacin orally before surgery as a single dose or as multiple doses. Samples of genital tract tissue and serum were obtained simultaneously during surgery.

RESULTS

In the single-dose group, trovafloxacin concentrations in genital tract tissues were measurable for up to 30 hours. Tissue concentrations of trovafloxacin after multiple doses were comparable to those after single doses. Mean tissue: serum concentration ratios after a single dose were greatest in the ovary (1.6 microg/g) and comparable in uterus, myometrium, cervix, and fallopian tubes (0.5 to 0.7 microg/g). Adverse events after a single dose were minor.

CONCLUSIONS

A daily dose of 200 mg trovafloxacin produces gynecologic tissue concentrations that persist for up to 30 hours at levels necessary to prevent or treat pelvic infections. This dosing regimen is well tolerated.

A double-blind, placebo-controlled, parallel group study of oral trovafloxacin on bowel microflora in healthy male volunteers

BACKGROUND

Treatment with oral antibiotic drugs generally influences normal fecal flora. These changes can be both beneficial (eg, elimination of aerobic, gram-negative bacilli) and detrimental (eg, the appearance of resistant pathogenic micro-organisms). Trovafloxacin, a new fluoroquinolone with in vitro activity against anaerobes, and gram-negative, gram-positive, and atypical pathogens, is a potentially beneficial antimicrobial for bowel sterilization. This double-blind trial investigated the effect of trovafloxacin on the normal microbial bowel flora of healthy male subjects.

METHODS

Subjects were randomized (in a 2:1 ratio) to receive either 200 mg trovafloxacin once daily for 10 days or a matching placebo. Fecal samples were collected at two baseline occasions, on visit days 4, 7, 10, and 17, and at follow-up. Bacterial species were identified and quantified in the fecal samples.

RESULTS

Twelve subjects received the active drug and seven received placebo. No Enterobacteriaceae were found in samples from days 4 to 10 in subjects receiving trovafloxacin. No changes in Enterobacteriaceae were found throughout the study in subjects receiving placebo. Incidental Enterobacteriaceae were isolated from subjects in the trovafloxacin group at the end of the study. No clinically significant differences were found in either group with respect to prevalence, appearance, or disappearance of aerobic gram-positive cocci, anaerobic bacteria, or yeasts. All tested Enterobacteriaceae were highly susceptible to trovafloxacin. No increase in minimum inhibitory concentration values was seen in day 17 and follow-up samples for isolated Escherichia coli strains. No Clostridium difficile was found in day 17 or follow-up samples from subjects in the trovafloxacin group. All tests for clostridium toxin were negative.

CONCLUSIONS

During the treatment period, E. coli could not be cultured from the feces of the 12 healthy subjects receiving 200 mg trovafloxacin daily during days 4 to 10. All isolated Enterobacteriaceae were susceptible to trovafloxacin and no changes in susceptibility were found after the treatment period. In subjects treated with trovafloxacin, the prevalence and number of gram-positive bacteria were rapidly reduced. Trovafloxacin is able to selectively and reversibly suppress bowel flora.

Pharmacokinetics and metabolism of single oral doses of trovafloxacin

Trovafloxacin, a new fluoronaphthyridone derivative related to fluoroquinolone antimicrobial drugs, has demonstrated the following characteristics: significant gram-positive and gram-negative activity; significant activity against anaerobes and atypical respiratory pathogens; approximately 11-hour elimination half-life, permitting once-daily administration; and good tissue penetration. Because <10% of an orally administered dose is recovered in urine as unchanged drug, the predominant route of trovafloxacin elimination appears to be nonrenal. The two studies described in this review examined the metabolism and excretion of trovafloxacin and compared the time course and concentrations of trovafloxacin and its metabolites in bile to those in serum. In the first study, four healthy male volunteers received a single, oral 200-mg dose of radiolabeled trovafloxacin. In the second study, three patients with indwelling nasobiliary tubes received a single 200-mg dose of trovafloxacin. Samples of blood, urine, bile, and feces were collected. Trovafloxacin in urine and serum was analyzed by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and in bile by HPLC-mass spectroscopy (MS). Levels of the N-acetyl metabolite in bile were determined by HPLC/UV/MS. Metabolites in serum, urine, and feces were determined by reverse-phase HPLC/MS, and radioactivity in these samples was assayed by liquid scintillation counting. In the first study, 63.3% and 23.1% of total radioactivity were recovered in feces and urine, respectively, with most of the radioactivity in urine in the form of the ester glucuronide metabolite (12.8%) and unchanged trovafloxacin (5.9%). Unchanged drug, the N-acetyl metabolite, and the N-sulfate of trovafloxacin accounted for 43.2%, 9.2%, and 3.9%, respectively, of the radioactivity in feces. In the second study, biliary trovafloxacin concentrations were highest between 1.5 and 10 hours postdose, and the maximum concentrations ranged from 18.9 to 37.9 microg/mL. The mean bile:serum ratio of trovafloxacin was 14.9, and the biliary concentration of parent drug was higher than that of its N-acetyl metabolite. In both studies, trovafloxacin was well tolerated, with no discontinuations due to adverse events. The pharmacokinetic profile of trovafloxacin in serum was consistent in healthy subjects and in individuals who had undergone recent hepatobiliary surgery. Trovafloxacin is metabolized primarily by the liver, through phase II metabolism (glucuronidation 13.2%, N-acetylation 10.4%, and N-sulfoconjugation 4.1%); minimal oxidative metabolism was detected. Renal elimination accounted for <10% of the administered dose. The high bile to serum ratio and higher trovafloxacin concentrations relative to metabolite concentrations are consistent with nonrenal elimination. These pharmacokinetic and pharmacodynamic results, together with a broad antimicrobial spectrum, long 11-hour elimination half-life, and low drug-interaction potential, suggest that trovafloxacin may be particularly appropriate for use in the surgical setting.

Concentrations of trovafloxacin in colonic tissue and peritoneal fluid after intravenous infusion of the prodrug alatrofloxacin in patients undergoing colorectal surgery

BACKGROUND

Trovafloxacin is a new fourth-generation fluoroquinolone whose pharmacokinetics and in vitro activity suggest that it is well suited for antibiotic prophylaxis in elective colorectal surgery. Alatrofloxacin is a prodrug that is rapidly hydrolyzed to trovafloxacin in the body.

METHODS

Twelve patients received a single dose of alatrofloxacin equivalent to 200 mg trovafloxacin by intravenous infusion over 1 hour. Surgery was started at various time points relative to infusion time to allow determination of trovafloxacin concentrations in serum, colonic tissue, and peritoneal fluid as a function of time.

RESULTS

The concentration in the earliest colonic tissue sample (1.4 hours after dosing) was 1.4 microg/g. The maximum colonic tissue concentration was 2.8 microg/g in a sample taken 2 hours after dosing. Colonic tissue/serum concentration ratios in samples taken 2-10 hours after the end of infusion ranged from 0.8 to 1.47. Concentrations of trovafloxacin in peritoneal fluid ranged from below the level of quantitation to 2.1 microg/mL at the time of colonic tissue sampling and from below the level of quantitation to 2.5 microg/mL at the time of wound closure. Alatrofloxacin was well tolerated.

CONCLUSIONS

After a single intravenous dose of alatrofloxacin equivalent to 200 mg trovafloxacin, trovafloxacin is distributed rapidly into colonic tissue and peritoneal fluids. Tissue concentrations approximate serum concentrations and decline in parallel for up to 10 hours after dosing.

Efficacy of trovafloxacin, a new quinolone antibiotic, in experimental staphylococcal endocarditis due to oxacillin-resistant strains

Therapeutic options for severe infections caused by strains of oxacillin-resistant Staphylococcus aureus (ORSA) and coagulase-negative staphylococci (ORSE) are very limited. With the increasing resistance of such strains to aminoglycosides, rifampin, and currently available quinolone agents, as well as the recent documentation of increasing resistance of ORSA to vancomycin (VANCO), new treatment alternatives are imperative. The in vivo efficacy of trovafloxacin (TROVA), a new quinolone agent with excellent antistaphylococcal activity in vitro, against experimental endocarditis (IE) due to beta-lactamase-producing ORSA and ORSE strains (ORSA and ORSE IE) was evaluated. TROVA (25 mg/kg of body weight intravenously [i.v.] twice daily [b.i.d]) was compared to VANCO (20 mg/kg i.v. b.i.d.) and two regimens of ampicillin-sulbactam (AMP-SUL; 200 mg/kg intramuscularly [i.m.] three times a day [t.i.d.] and 20 mg/kg i.m. b.i.d.), with all agents given for 3 or 6 days. AMP-SUL was included as a comparative treatment regimen because of its proven efficacy against experimental ORSA and ORSE IE. For both ORSA and ORSE IE, TROVA, AMP-SUL, and VANCO each reduced staphylococcal densities in vegetations compared to untreated controls (P < 0.01). For ORSA IE, TROVA was the most rapidly bactericidal agent--although not to a statistically significant degree--correlating with its superior bactericidal effect in vitro compared to those of VANCO and AMP-SUL.

Safety of trovafloxacin in treatment of lower respiratory tract infections

Safety and toleration of oral trovafloxacin has been assessed in Phase III trials in patients with acute lower respiratory tract infections. Patients were treated orally with either trovafloxacin 100 or 200 mg (n=881) or a comparator (500 or 1000 mg amoxicillin, or 625 mg amoxicillin/clavulanic acid; n = 593). Adverse events were recorded in 112 (12.7%) trovafloxacin- and 74 (12.5%) comparator-treated patients. Frequency of effects on the autonomic nervous, musculoskeletal, respiratory, special senses, urinary and reproductive systems was <1%. Photosensitivity reactions were not reported in trovafloxacin-treated patients. Central or peripheral nervous system adverse effects (headache and dizziness) were slightly more common in trovafloxacin-treated patients (4.4% vs 1.9%). Patients treated with comparators experienced gastrointestinal events more frequently (6.1% vs 8.3%). Comparable incidences of adverse events were reported in patients > or = 65-years-old. Most events were mild to moderate in severity. Treatment was discontinued because of an adverse event in 18 (2%) trovafloxacin- and four (0.7%) comparator-treated patients. Despite the high prevalence of risk factors, serious adverse events were rare and the mortality rate over the 35-day study period was low: trovafloxacin 0.8%, comparator agents 1.5%. Laboratory test abnormalities were recorded in less than 1% of patients in either treatment group.

Trovafloxacin versus high-dose amoxicillin (1 g three times daily) in the treatment of community-acquired bacterial pneumonia

Once-daily trovafloxacin 200 mg was compared with high-dose amoxicillin, 1 g three times daily, given for 7 to 10 days. At end of treatment (day 10), the response was clinically successful (cure + improvement) in 93% of 152 clinically evaluable trovafloxacin patients and in 89% of 160 amoxicillin patients. At study end (day 35), respective rates were 91% and 81% (95% confidence interval: 1.6, 17.6; P=0.01). In evaluable patients with positive baseline radiographs, 93% of trovafloxacin and 88% of amoxicillin patients demonstrated radiological resolution at end of treatment. Streptococcus pneumoniae and Haemophilus influenzae eradication rates were comparable at end of treatment in both treatment groups, but at study end Streptococcus pneumoniae eradication rates were higher in trovafloxacin patients (100% vs 81%). At study end, all four trovafloxacin patients with baseline penicillin-resistant Streptococcus pneumoniae were clinically cured with pathogen eradication, whereas two of five amoxicillin patients with baseline penicillin-resistant Streptococcus pneumoniae were clinical failures with pathogen persistence. For patients in whom no pathogen was identified, trovafloxacin was significantly more effective at end of treatment (P=0.096) and study end (P=0.013). Treatment-related adverse events were comparable; the most common were headache, vomiting and dizziness in trovafloxacin patients, and diarrhoea. headache and abdominal pain in amoxicillin patients.

Single- and multiple-dose administration, dosing regimens, and pharmacokinetics of trovafloxacin and alatrofloxacin in humans

A simplified dosing algorithm for trovafloxacin was evaluated following a single-dose infusion of alatrofloxacin at trovafloxacin equivalent doses of 30, 100, 200, 300 and 400 mg (57 subjects), and multiple doses of 200, 300 and 400 mg (30 subjects). Maximum serum concentration and area under the concentration-time curve for trovafloxacin increased with dose. Trovafloxacin clearance (82-85 ml x h/kg) and volume of distribution (1.3-1.6 l/kg) were independent of dose. Infusion of alatrofloxacin at a trovafloxacin equivalent dose of 300 mg at 1, 2 or 3 mg/ml over 1 h did not alter the pharmacokinetics of trovafloxacin. A plot of the weight-adjusted dose of trovafloxacin in individual subjects against the maximum serum concentration following single and multiple dosing, indicated that the maximum serum concentration increased 1 microg/ml for each 1 mg/kg of trovafloxacin administered. Thus, a prior knowledge of the desired serum concentration will permit appropriate dosing without the use of complex nomograms in patients with normal hepatic function.