Telavancin in Hospital-Acquired and Ventilator-Associated Pneumonia (HAP/VAP) Caused by Staphylococcus aureus: Post Hoc Analysis of 2 Randomized, Controlled Trials.

INTRODUCTION: The efficacy and safety of telavancin versus vancomycin in microbiologically evaluable patients with hospital-acquired or ventilator-associated pneumonia (HAP/VAP) caused by Staphylococcus aureus with vancomycin minimum inhibitory concentration (MIC) ≥ 1.0 µg/mL was analyzed using data derived from previously reported Assessment of Telavancin for Treatment of Hospital-Acquired Pneumonia (ATTAIN) trials. METHODS: This post hoc subgroup analysis of two randomized, double-blind, comparator-controlled, parallel-group phase 3 trials conducted at 274 sites in 38 countries included 194 microbiologically evaluable patients with HAP/VAP caused by monomicrobial S. aureus with vancomycin MIC ≥ 1.0 µg/mL. Patients received intravenous telavancin (10 mg/kg every 24 h) or intravenous vancomycin (1 g every 12 h with site-specific modifications) for 7-21 days. Efficacy was assessed by clinical cure, defined as improvement or non-progression of radiographic findings at end of treatment and resolution of pneumonia signs and symptoms at follow-up/test-of-cure visits, and survival 28 days post-randomization. Safety was assessed from categorical shifts in creatinine clearance during therapy and adverse events (AEs). RESULTS: Clinical cure rates were numerically greater following telavancin versus vancomycin treatment overall (85.4% vs. 74.3%; treatment difference [95% confidence interval (CI)], 11.1% [- 0.002%, 22.2%]) and in patients aged ≥ 65 years (81.6% vs. 66.2%; treatment difference [95% CI], 15.5% [- 0.9%, 30.2%]) patients with VAP (92.3% vs. 47.6%; treatment difference [95% CI], 44.7% [18.1%, 64.9%]), and patients with baseline Acute Physiology And Chronic Health Evaluation II score ≥ 20 (71.4% vs. 55.6%; treatment difference [95% CI], 15.9% [- 11.7%, 40.5%]). Renal function declined in 7 (7.9%) patients receiving telavancin and 6 (5.7%) patients receiving vancomycin. Survival proportion was numerically higher (85.2% vs. 80.2%; treatment difference [95% CI], 5.0% [- 5.8%, 15.8%]) and AEs were comparable in patients treated with telavancin versus vancomycin. CONCLUSION: Telavancin is an alternative to vancomycin for HAP/VAP caused by S. aureus with vancomycin MIC ≥ 1 µg/mL. FUNDING: Theravance Biopharma R&D, Inc., South San Francisco, CA, USA.

Assessment of telavancin minimal inhibitory concentrations by revised broth microdilution method in phase 3 complicated skin and skin-structure infection clinical trial isolates.

The broth microdilution (BMD) MIC testing method for telavancin was recently revised BMD (rBMD) to improve accuracy and reproducibility. Staphylococcus aureus isolates from telavancin phase 3 complicated skin and skin-structure infection (cSSSI) studies were tested using the rBMD method. Retesting of 1132 isolates produced MICs ranging from ≤0.015 to 0.12µg/mL that were 8-fold lower than the original method. All isolates tested remained susceptible to telavancin at the revised susceptibility breakpoint of 0.12µg/mL. The clinical cure and microbiological eradication rates were 90% (368/409) and 89% (366/409) for telavancin-treated patients, and were similar for patients with methicillin-susceptible and -resistant S. aureus isolates and S. aureus isolates with elevated vancomycin MICs (≥1µg/mL). The data presented here are aimed to update the literature and better inform clinicians and clinical microbiologists about the revised telavancin MICs, as well as the corresponding clinical and microbiological cure rates for cSSSI patients.

Assessment of Minimum Inhibitory Concentrations of Telavancin by Revised Broth Microdilution Method in Phase 3 Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia Clinical Isolates.

INTRODUCTION: The broth microdilution method (BMD) for testing telavancin minimum inhibitory concentrations (MICs) was revised (rBMD) in 2014 to improve the accuracy, precision, and reproducibility of the testing method. The aim of this study was to determine the effect of the revised method on telavancin MIC values for Staphylococcus aureus (S. aureus) clinical isolates obtained from hospital-acquired pneumonia (HAP) patients. METHODS: Isolates from patients who participated in the phase 3 Assessment of Telavancin for Treatment of HAP Studies were retested using the rBMD method. RESULTS: Retesting of 647 isolates produced a range of telavancin MIC values from 0.015 µg/mL to 0.12 µg/mL with MIC50/90 values of 0.06/0.06 µg/mL for the total pool of samples. For methicillin-resistant S. aureus (MRSA), MIC50/90 values were 0.06/0.12 µg/mL. These values are up to 4-fold lower than MIC50/90 values obtained using the original method. These results were used in part to justify lowering the telavancin breakpoints. All tested isolates remained susceptible to telavancin at the revised susceptibility breakpoint of ≤0.12 µg/mL. Overall, the clinical cure rate for microbiologically evaluable telavancin-treated patients was 78% for S. aureus, 76% for patients with MRSA, and 79% for patients with isolates with reduced susceptibility to vancomycin (MIC ≥1 µg/mL). CONCLUSION: Results from the rBMD method support the in vitro potency of telavancin against S. aureus. TRIAL REGISTRATION: ATTAIN (NCT00107952 and NCT00124020). FUNDING: Theravance Biopharma Antibiotics, Inc.

Telavancin hospital-acquired pneumonia trials: impact of Gram-negative infections and inadequate Gram-negative coverage on clinical efficacy and all-cause mortality.

BACKGROUND: When hospital-acquired or ventilator-associated bacterial pneumonia (HABP/VABP) is caused by gram-positive and gram-negative pathogens or both (mixed infections), the adequacy of gram-negative coverage (GNC) can confound the assessment of a gram-positive agent under study. This analysis examines the influence of gram-negative infections and the adequacy of GNC on clinical efficacy and all-cause mortality in the telavancin HABP/VABP phase 3 ATTAIN trials (Assessment of Telavancin for Treatment of Hospital-Acquired Pneumonia). METHODS: This post hoc analysis evaluated 3 patient groups from ATTAIN: (1) gram-positive-only infections, (2) gram-positive-only and mixed infections-adequate GNC, and (3) gram-negative-only infections and mixed infections with inadequate GNC. For each, clinical efficacy at test of cure and all-cause mortality at day 28 were compared for telavancin and vancomycin. RESULTS/CONCLUSIONS: In the ATTAIN safety population there were 16 more deaths in the telavancin arms than in the vancomycin arms. Of these, 13 were in patients with gram-negative-only infections (n = 9) or with mixed infections and inadequate GNC (n = 4) and all had estimated baseline creatinine clearances of <30ml/min. Based on this analysis, clinical response and all-cause mortality could be confounded because there were more patients with gram-negative pathogens at baseline and more patients received inadequate treatment of these gram-negative infections in the telavancin groups.

Telavancin for Acute Bacterial Skin and Skin Structure Infections, a Post Hoc Analysis of the Phase 3 ATLAS Trials in Light of the 2013 FDA Guidance.

Two phase 3 ATLAS trials demonstrated noninferiority of telavancin compared with vancomycin for complicated skin and skin structure infections. Data from these trials were retrospectively evaluated according to 2013 U.S. Food and Drug Administration (FDA) guidance on acute bacterial skin and skin structure infections. This post hoc analysis included patients with lesion sizes of ≥75 cm(2) and excluded patients with ulcers or burns (updated all-treated population; n = 1,127). Updated day 3 (early) clinical response was defined as a ≥20% reduction in lesion size from baseline and no rescue antibiotic. Updated test-of-cure (TOC) clinical response was defined as a ≥90% reduction in lesion size, no increase in lesion size since day 3, and no requirement for additional antibiotics or significant surgical procedures. Day 3 (early) clinical responses were achieved in 62.6% and 61.0% of patients receiving telavancin and vancomycin, respectively (difference, 1.7%, with a 95% confidence interval [CI] of -4.0% to 7.4%). Updated TOC visit cure rates were similar for telavancin (68.0%) and vancomycin (63.3%), with a difference of 4.8% (95% CI, -0.7% to 10.3%). Adopting current FDA guidance, this analysis corroborates previous noninferiority findings of the ATLAS trials of telavancin compared with vancomycin.

Pharmacokinetics of intravenous telavancin in healthy subjects with varying degrees of renal impairment.

PURPOSE: We evaluated the effect of renal impairment (RI) on the pharmacokinetics of telavancin and hydroxypropylbetadex (excipient in the telavancin drug product). METHODS: Adults with normal, mild, moderate or severe RI or end-stage renal disease (ESRD) receiving haemodialysis were included in two open-label, phase I studies of single-dose telavancin at 7.5 mg/kg (study A, n = 29) or 10 mg/kg (study B, n = 43). Pharmacokinetic analysis of telavancin and hydroxypropylbetadex plasma concentration versus time was performed in these subjects. RESULTS: The results in studies A and B were similar: telavancin systemic exposure (area under the concentration-time curve from 0 to infinity [AUC0-∞]) increased with RI. Telavancin half-life (h, mean ± SD) increased in subjects with severe RI compared with subjects with normal renal function from 6.9 ± 0.6 in study A and 6.5 ± 0.9 in study B to 14.5 ± 1.3 and 11.8 ± 6.7, respectively. Conversely, clearance (ml/h/kg, mean ± SD) decreased in subjects with severe RI compared with subjects with normal renal function from 13.7 ± 2.1 in study A and 17.0 ± 3.2 in study B to 6.18 ± 0.63 and 6.5 ± 1.5, respectively. Systemic exposures for hydroxypropylbetadex also increased with severity of RI. CONCLUSIONS: Results from two independent phase 1 studies suggest that dose adjustment of telavancin is required in subjects with varying degrees of RI.

Potential role for telavancin in bacteremic infections due to gram-positive pathogens: focus on Staphylococcus aureus.

Staphylococcus aureus bacteremia (SAB) is one of the most common serious bacterial infections and the most frequent invasive infection due to methicillin-resistant S. aureus (MRSA). Treatment is challenging, particularly for MRSA, because of limited treatment options. Telavancin is a bactericidal lipoglycopeptide antibiotic that is active against a range of clinically relevant gram-positive pathogens including MRSA. In experimental animal models of sepsis telavancin was shown to be more effective than vancomycin. In clinically evaluable patients enrolled in a pilot study of uncomplicated SAB, cure rates were 88% for telavancin and 89% for standard therapy. Among patients with infection due to only gram-positive pathogens enrolled in the 2 phase 3 studies of telavancin for treatment of hospital-acquired pneumonia, cure rates for those with bacteremic S. aureus pneumonia were 41% (9/22, telavancin) and 40% (10/25, vancomycin) with identical mortality rates. These data support further evaluation of telavancin in larger, prospective studies of SAB.

Clinical, economic and societal impact of antibiotic resistance.

The concern over antibiotic resistance has been voiced since the discovery of modern antibiotics > 75 years ago. The concerns have only increased with time, with efforts to control resistance caused by widespread overuse of antibiotics in human medicine and far more than appreciated use in the feeding of animals for human consumption to promote growth. The problem is worldwide, but certain regions and selected health care institutions report far more resistance, including strains of Gram-negative bacteria that are susceptible only to the once discarded drugs polymyxin B or colistin, and pan-resistant strains are on the rise. One of the central efforts to control resistance, apart from antimicrobial stewardship, is the development of new antimicrobial agents. This has lagged significantly over the past 10 - 15 years, for a variety of reasons; but promising new agents are being developed, unfortunately none thus far addressing all potentially resistant strains. There is the unlikely, but not unreal, possibility that we could return to a pre-antibiotic era, where morbidity and mortality rates have risen dramatically and routine surgical procedures are not performed for fear of post-operative infections. The onus of control of resistance is a moral imperative that falls on the shoulders of all.

Serum inhibitory and bactericidal activity of telavancin in non-infected subjects with severe renal impairment or end-stage renal disease.

Telavancin biological activity, determined by serum titers against a reference strain of Staphylococcus aureus, was maintained in the serum of subjects with severe renal impairment or end-stage renal disease suggesting that there is no apparent effect of renal function on in vitro activity of telavancin.

Variability in telavancin cross-reactivity among vancomycin immunoassays.

Telavancin is a semisynthetic lipoglycopeptide with a dual mechanism of action against Gram-positive pathogens. Two brief reports have suggested potential cross-reactivity of telavancin with the vancomycin particle-enhanced turbidometric immunoassay (PETIA). The purpose of this study was to evaluate several commercially available vancomycin immunoassays (fluorescence polarization [FPIA], enzyme-multiplied immunoassays [EMIT], PETIA, and chemiluminescent immunoassay [CMIA]) for cross-reactivity with telavancin. Seven sites were selected to analyze serum samples for vancomycin. Each site received a set of samples (n = 18) which combined drug-free serum with telavancin, 7-OH telavancin metabolite, or vancomycin. Immunoassays demonstrating potential cross-reactivity were further evaluated by sending a duplicate sample set to multiple laboratories. Cross-reactivity was defined as the percent theoretical concentration (reported concentration/theoretical concentration × 100). No cross-reactivity was seen with FPIA or EMIT. Within the theoretical concentration range of 5 to 120 µg/ml of telavancin, the Synchron PETIA system reported vancomycin concentrations ranging from 4.7 to 54.2 µg/ml compared to vancomycin concentrations from 1.1 to 5.6 µg/ml for the Vista PETIA system. The Architect CMIA system reported vancomycin concentrations in the range of 0.27 to 0.97 µg/ml, whereas Advia Centaur XP CMIA reported vancomycin concentrations between 1.6 and 31.6 µg/ml. The Architect CMIA immunoassay had the lowest percent cross-reactivity (0.8 to 5.4%), while the Synchron PETIA immunoassay demonstrated the highest percent cross-reactivity (45.2 to 53.8%). Telavancin samples measured by liquid chromatography-mass spectroscopy were within 93.9 to 122% of theoretical concentrations. Vancomycin concentrations were not measured in any 7-OH telavancin-spiked sample. Vancomycin concentrations measured by liquid chromatography-mass spectroscopy were within 57.2 to 113% of theoretical concentrations. PETIA and CMIA measured vancomycin concentrations in telavancin-spiked samples. Significant variability in percent cross-reactivity was observed for each platform regardless of immunoassay method.

A randomized Phase 2 trial of telavancin versus standard therapy in patients with uncomplicated Staphylococcus aureus bacteremia: the ASSURE study.

BACKGROUND: Staphylococcus aureus bacteremia is a common infection associated with significant morbidity and mortality. Telavancin is a bactericidal lipoglycopeptide active against Gram-positive pathogens, including methicillin-resistant S. aureus (MRSA). We conducted a randomized, double-blind, Phase 2 trial in patients with uncomplicated S. aureus bacteremia. METHODS: Patients were randomized to either telavancin or standard therapy (vancomycin or anti-staphylococcal penicillin) for 14 days. Continuation criteria were set to avoid complicated S. aureus bacteremia. The primary end point was clinical cure at 84 days. RESULTS: In total, 60 patients were randomized and 58 received ≥1 study medication dose (all-treated), 31 patients fulfilled inclusion/exclusion and continuation criteria (all-treated target [ATT]) (telavancin 15, standard therapy 16), and 17 patients were clinically evaluable (CE) (telavancin 8, standard therapy 9). Mean age (ATT) was 60 years. Intravenous catheters were the most common source of S. aureus bacteremia and ~50% of patients had MRSA. A similar proportion of CE patients were cured in the telavancin (88%) and standard therapy (89%) groups. All patients with MRSA bacteremia were cured and one patient with MSSA bacteremia failed study treatment in each group. Although adverse events (AEs) were more common in the telavancin ATT group (90% vs. 72%), AEs leading to drug discontinuation were similar (7%) in both treatment arms. Potentially clinically significant increases in serum creatinine (≥1.5 mg/dl and at least 50% greater than baseline) were more common in the telavancin group (20% vs. 7%). CONCLUSIONS: This study suggests that telavancin may have utility for treatment of uncomplicated S. aureus bacteremia; additional studies are warranted. (Telavancin for Treatment of Uncomplicated Staphylococcus Aureus Bacteremia (ASSURE); NCT00062647).

Clinical utility of telavancin for treatment of hospital-acquired pneumonia: focus on non-ventilator-associated pneumonia.

BACKGROUND: Hospital-acquired pneumonia (HAP) is the most common health care-associated infection contributing to death. Studies have indicated that there may be differences in the causative pathogens and outcomes of ventilator-associated pneumonia (VAP) and non-ventilator-associated pneumonia (NV-HAP). However, with limited NV-HAP-specific data available, treatment is generally based on data from studies of VAP. The Phase 3 Assessment of Telavancin for Treatment of Hospital-Acquired Pneumonia (ATTAIN) studies were two double-blind randomized controlled trials that demonstrated the non-inferiority of telavancin to vancomycin for treatment of Gram-positive HAP. We conducted a post hoc subgroup analysis of patients enrolled in the ATTAIN studies who had NV-HAP. METHODS: Data from the two ATTAIN studies were pooled, and patients with NV-HAP were analyzed. The all-treated (AT) population consisted of all randomized patients who received ≥1 dose of study medication, and the clinically evaluable (CE) population consisted of AT patients who were protocol-adherent or who died on or after study day 3, where death was attributable to the HAP episode under study. The primary endpoint was clinical response (cure, failure, or indeterminate) at the follow-up/test of cure visit, conducted 7-14 days after the end of therapy. RESULTS: A total of 1,076 patients (71.6% of overall ATTAIN AT population) had NV-HAP (533 and 543 patients in the telavancin and vancomycin treatment groups, respectively). Clinical cure rates in the CE population were similar for patients with NV-HAP treated with telavancin and vancomycin (83.1% [201/242] and 84.1% [233/277], respectively). In patients with methicillin-resistant Staphylococcus aureus isolated at baseline, cure rates in the CE population were 74.8% (77/103) for telavancin and 79.3% (96/121) for vancomycin. The incidence of adverse events, serious adverse events, and deaths in patients with NV-HAP was similar whether patients received telavancin or vancomycin. CONCLUSION: This post hoc subgroup analysis of the ATTAIN studies demonstrated similar cure rates for telavancin and vancomycin for treatment of NV-HAP.

Effect of vancomycin serum trough levels on outcomes in patients with nosocomial pneumonia due to Staphylococcus aureus: a retrospective, post hoc, subgroup analysis of the Phase 3 ATTAIN studies.

BACKGROUND: Existing data are not consistently supportive of improved clinical outcome when vancomycin dosing regimens aimed at achieving target trough levels are used. A retrospective, post hoc, subgroup analysis of prospectively collected data from the Phase 3 ATTAIN trials of telavancin versus vancomycin for treatment of nosocomial pneumonia was conducted to further investigate the relationship between vancomycin serum trough levels and patient outcome. METHODS: Study patients were enrolled in 274 study sites across 38 countries. A total of 98 patients had Staphylococcus aureus nosocomial pneumonia and vancomycin serum trough levels available. These patients were grouped according to their median vancomycin trough level; < 10 µg/mL, 10 µg/mL to < 15 µg/mL, and ≥ 15 µg/mL. RESULTS: Clinical cure rates in the < 10 µg/mL, 10 µg/mL to < 15 µg/mL, and ≥ 15 µg/mL vancomycin trough level groups were 70% (21/30), 55% (18/33), and 49% (17/35), respectively (p = 0.09), and the frequencies of patient death were 10% (3/30), 15% (5/33), and 20% (7/35), respectively (p = 0.31). Renal adverse events were more frequent in the ≥ 15 µg/mL (17% [6/35]) than the < 10 µg/mL (0%) and 10 µg/mL to < 15 µg/mL (3% [1/33]) trough level groups (p < 0.01). When patients with acute renal failure or vancomycin exposure within 7 days prior to study medication were excluded, clinical cure rates in the < 10 µg/mL, 10 µg/mL to < 15 µg/mL, and ≥ 15 µg/mL vancomycin trough level groups (71% [12/17], 60% [9/15], and 27% [3/11], respectively; p = 0.04) and the number of deaths (12% [2/17], 20% [3/15], and 45% [5/11], respectively; p = 0.07) demonstrated a trend towards worse outcomes in the higher vancomycin trough level groups. CONCLUSIONS: The findings of our study suggest that higher vancomycin trough levels do not result in improved clinical response but likely increase the incidence of nephrotoxicity. TRIAL REGISTRATION: NCT00107952 and NCT00124020.

The ATTAIN trials: efficacy and safety of telavancin compared with vancomycin for the treatment of hospital-acquired and ventilator-associated bacterial pneumonia.

Hospital-acquired bacterial pneumonia (HABP) is the second most common nosocomial infection in the USA and the leading cause of mortality among hospital-acquired infections. An increasing proportion of HABP cases are the result of infection with methicillin-resistant Staphylococcus aureus (MRSA). Telavancin is a once-daily injectable, semisynthetic lipoglycopeptide antimicrobial with bactericidal activity against susceptible Gram-positive pathogens, including MRSA. The two methodologically identical Phase III ATTAIN studies demonstrated that telavancin was noninferior to vancomycin for the treatment of HABP, including ventilator-associated bacterial pneumonia, due to S. aureus (including methicillin-sensitive S. aureus and MRSA). Telavancin showed a similar safety profile to vancomycin, except that in patients with moderate-to-severe renal impairment, there was increased mortality, which warrants caution when using telavancin in this population. Now approved in the USA for the treatment of HABP, including ventilator-associated bacterial pneumonia, caused by susceptible isolates of S. aureus when other alternatives are not suitable, telavancin offers another therapeutic option.

Telavancin for hospital-acquired pneumonia: clinical response and 28-day survival.

U.S. Food and Drug Administration draft guidance for future antibiotic clinical trials of bacterial nosocomial pneumonia recommends the use of diagnostic criteria according to American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines and the use of a primary endpoint of 28-day all-cause mortality. The effect of applying these guidelines on outcomes of phase III nosocomial pneumonia studies of telavancin was evaluated in a post hoc analysis. ATS/IDSA criteria were applied in a blind fashion to the original all-treated (AT) group. Clinical cure rates at final follow-up were determined in the refined AT and clinically evaluable (CE) groups (ATS/IDSA-AT and ATS/IDSA-CE, respectively). The exploratory endpoint of 28-day survival was evaluated for the ATS/IDSA-AT group. Noninferiority of telavancin versus vancomycin was demonstrated, with similar cure rates in the ATS/IDSA-AT (59% versus 59%) and ATS/IDSA-CE (83% versus 80%) groups. Cure rates favored telavancin in ATS/IDSA-CE patients where Staphylococcus aureus was the sole pathogen (86% versus 75%). Overall, 28-day survival rates were similar in the telavancin (76%) and vancomycin (77%) groups but lower in telavancin-treated patients with preexisting moderate-to-severe renal impairment (creatinine clearance [CLCR] of <50 ml/min). Telavancin should be administered to patients with moderate-to-severe renal impairment only if treatment benefit outweighs the risk or if no suitable alternatives are available.

Impact of telavancin on prothrombin time and activated partial thromboplastin time as determined using point-of-care coagulometers.

Telavancin is approved in the United States, Canada, and Europe (At the time of submission, the telavancin European marketing authorization for nosocomial pneumonia was suspended until Theravance provides evidence of a new European Medicines Agency approved supplier) as an antibiotic to treat certain Gram-positive bacterial skin infections. Telavancin has been shown to prolong plasmatic prothrombin (PT) and activated partial thromboplastin (aPTT) clotting times in clinical diagnostic lab-based assays. In this study, we evaluated the potential for telavancin to prolong whole blood PT/International Normalized Ratio (INR) and aPTT tests on point-of-care (POC) instruments. Whole blood collected from 8 healthy subjects was supplemented with telavancin to final concentrations of 0, 10, 20, and 100 µg/ml. Final concentrations were selected to match trough, twice trough, and peak plasma levels following the approved 10 mg/kg dose. Four widely employed POC coagulation instruments were chosen to be representative of the POC platforms currently in use.. These systems were the Roche Coaguchek XS, the Abbott iSTAT, the ITC Hemochron SIG+, and the Alere INRatio2 POC devices. The PT/INR measured by the Coaguchek XS showed the greatest sensitivity to the presence of telavancin. The PT/INR measured by the Hemochron SIG+ and iSTAT were sensitive to telavancin but to a lesser extent. The INRatio2 was the least sensitive to the presence of telavancin when testing the whole blood PT/INR. Only the Hemochron SIG+ device was capable of measuring aPTT and showed a concentration-dependent increase in aPTT. This study supports the current recommendation that PT and aPTT monitoring be conducted immediately to the next dose of telavancin when coagulation parameters are tested using POC instrumentation.

In vitro activity of telavancin and occurrence of vancomycin heteroresistance in isolates from patients enrolled in phase 3 clinical trials of hospital-acquired pneumonia.

In phase 3 studies of the efficacy of telavancin for the treatment of hospital-acquired pneumonia, 704 Gram-positive and 627 Gram-negative aerobic bacterial pathogens were obtained at baseline from 1503 patients. The majority of Gram-positive isolates (n = 650 [92%]) were Staphylococcus aureus, of which 410 (63%) were methicillin-resistant (MRSA). Of the MRSA isolates, 9.5% were identified as heterogeneous vancomycin-intermediate S. aureus. All Gram-positive isolates were inhibited by ≤1 µg/mL of telavancin.

TD-1792 versus vancomycin for treatment of complicated skin and skin structure infections.

TD-1792 is a first-in-class glycopeptide-cephalosporin heterodimer that exhibits bactericidal activity against Gram-positive pathogens. We conducted a randomized, double-blind, active-control, phase II trial in patients with complicated skin and skin structure infections caused by suspected or confirmed Gram-positive organisms. Patients 18 to 65 years old were randomized to receive 7 to 14 days of either TD-1792 (2 mg/kg of body weight intravenously [i.v.] every 24 h [q24h]) or vancomycin (1 g i.v. q12h, with dosage regimens adjusted per site-specific procedures). A total of 197 patients were randomized and received at least one dose of study medication. Rates of clinical success at the test-of-cure evaluation were similar in all analysis populations. Among 170 clinically evaluable patients, cure rates were 91.7% and 90.7% in the TD-1792 and vancomycin groups, respectively (95% confidence interval [CI] of -7.9 to 9.7 for the difference). In microbiologically evaluable patients with methicillin-resistant Staphylococcus aureus at baseline (n = 75), cure rates were 94.7% in the TD-1792 group and 91.9% in the vancomycin group. Microbiological eradication of Gram-positive pathogens (n = 126) was achieved in 93.7% and 92.1% of patients in the TD-1792 and vancomycin groups, respectively. Seven patients were discontinued from study medication due to an adverse event (AE): 2 and 5 in the TD-1792 and vancomycin groups, respectively. AEs were of similar types and severities between the two groups, other than pruritus, which was more common in patients who received vancomycin. No patients in the TD-1792 group experienced a serious AE. This study supports further clinical development of TD-1792 in patients with Gram-positive infection.

Efficacy of telavancin in patients with specific types of complicated skin and skin structure infections.

BACKGROUND: Telavancin is approved in the USA and Canada for the treatment of Gram-positive complicated skin and skin structure infections (cSSSIs) based on the results of the Phase 3 Assessment of TeLAvancin in complicated Skin and skin structure infections (ATLAS) trials, which demonstrated non-inferiority of telavancin to vancomycin. METHODS: We conducted a post hoc analysis of the ATLAS studies (ClinicalTrials.gov identifiers NCT00091819 and NCT00107978) to explore the efficacy of telavancin in patients with various types of cSSSIs. RESULTS: A total of 1794 patients were included in this analysis; 1434 patients were clinically evaluable (CE) and 563 of these had methicillin-resistant Staphylococcus aureus (MRSA). Among CE patients with major abscesses (n = 619), cure rates were 91% for telavancin and 90% for vancomycin (95% CI for the difference -3.6 to 5.7). In patients with infective cellulitis (n = 519), cure was achieved in 87% and 88% of telavancin- and vancomycin-treated patients, respectively (95% CI for the difference -6.2 to 5.2). Cure rates in patients with wound infections were 85% in the telavancin group and 86% in the vancomycin group (95% CI for the difference -10.5 to 9.0). Cure rates for each type of cSSSI in patients infected with MRSA were also similar between the two treatment arms. Among CE patients infected with Panton-Valentine leucocidin (PVL)-positive MRSA (n = 447), cure rates were 93% for telavancin and 90% for vancomycin (95% CI for the difference -2.2 to 8.2). CONCLUSIONS: Cure rates were similar for telavancin and vancomycin in patients with different types of cSSSIs, including infections caused by MRSA and PVL-positive strains of MRSA.