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.

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.

Presence of genes encoding panton-valentine leukocidin is not the primary determinant of outcome in patients with hospital-acquired pneumonia due to Staphylococcus aureus.

The impact of Panton-Valentine leukocidin (PVL) on the outcome in Staphylococcus aureus pneumonia is controversial. We genotyped S. aureus isolates from patients with hospital-acquired pneumonia (HAP) enrolled in two registrational multinational clinical trials for the genetic elements carrying pvl and 30 other virulence genes. A total of 287 isolates (173 methicillin-resistant S. aureus [MRSA] and 114 methicillin-susceptible S. aureus [MSSA] isolates) from patients from 127 centers in 34 countries for whom clinical outcomes of cure or failure were available underwent genotyping. Of these, pvl was detected by PCR and its product confirmed in 23 isolates (8.0%) (MRSA, 18/173 isolates [10.4%]; MSSA, 5/114 isolates [4.4%]). The presence of pvl was not associated with a higher risk for clinical failure (4/23 [17.4%] versus 48/264 [18.2%]; P = 1.00) or mortality. These findings persisted after adjustment for multiple potential confounding variables. No significant associations between clinical outcome and (i) presence of any of the 30 other virulence genes tested, (ii) presence of specific bacterial clone, (iii) levels of alpha-hemolysin, or (iv) delta-hemolysin production were identified. This study suggests that neither pvl presence nor in vitro level of alpha-hemolysin production is the primary determinant of outcome among patients with HAP caused by S. aureus.

Telavancin versus vancomycin for hospital-acquired pneumonia due to gram-positive pathogens.

BACKGROUND: Telavancin is a lipoglycopeptide bactericidal against gram-positive pathogens. METHODS: Two methodologically identical, double-blind studies (0015 and 0019) were conducted involving patients with hospital-acquired pneumonia (HAP) due to gram-positive pathogens, particularly methicillin-resistant Staphylococcus aureus (MRSA). Patients were randomized 1:1 to telavancin (10 mg/kg every 24 h) or vancomycin (1 g every 12 h) for 7-21 days. The primary end point was clinical response at follow-up/test-of-cure visit. RESULTS: A total of 1503 patients were randomized and received study medication (the all-treated population). In the pooled all-treated population, cure rates with telavancin versus vancomycin were 58.9% versus 59.5% (95% confidence interval [CI] for the difference, -5.6% to 4.3%). In the pooled clinically evaluable population (n = 654), cure rates were 82.4% with telavancin and 80.7% with vancomycin (95% CI for the difference, -4.3% to 7.7%). Treatment with telavancin achieved higher cure rates in patients with monomicrobial S. aureus infection and comparable cure rates in patients with MRSA infection; in patients with mixed gram-positive/gram-negative infections, cure rates were higher in the vancomycin group. Incidence and types of adverse events were comparable between the treatment groups. Mortality rates for telavancin-treated versus vancomycin-treated patients were 21.5% versus 16.6% (95% CI for the difference, -0.7% to 10.6%) for study 0015 and 18.5% versus 20.6% (95% CI for the difference, -7.8% to 3.5%) for study 0019. Increases in serum creatinine level were more common in the telavancin group (16% vs 10%). CONCLUSIONS: The primary end point of the studies was met, indicating that telavancin is noninferior to vancomycin on the basis of clinical response in the treatment of HAP due to gram-positive pathogens.

Presence of genes encoding the panton-valentine leukocidin exotoxin is not the primary determinant of outcome in patients with complicated skin and skin structure infections due to methicillin-resistant Staphylococcus aureus: results of a multinational trial.

The role of Panton-Valentine leukocidin (PVL) in determining the severity and outcome of complicated skin and skin structure infections (cSSSI) caused by methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) is controversial. We evaluated potential associations between clinical outcome and PVL status by using MRSA isolates from patients enrolled in two large, multinational phase three clinical trials assessing telavancin for the treatment of cSSSI (the ATLAS program). MRSA isolates from microbiologically evaluable patients were genotyped by pulsed-field gel electrophoresis (PFGE) and PCR for pvl and 31 other putative virulence determinants. A single baseline pathogen of MRSA was isolated from 522 microbiologically evaluable patients (25.1%) among 2,079 randomized patients. Of these MRSA isolates, 83.2% (432/519) exhibited the USA300 PFGE genotype and 89.1% (465/522) were pvl positive. Patients with pvl-positive MRSA were more likely than those with pvl-negative MRSA to be young, to be North American, and to present with major abscesses (P < 0.001 for each). Patients were significantly more likely to be cured if they were infected with pvl-positive MRSA than if they were infected with pvl-negative MRSA (91.6% versus 80.7%; P = 0.015). This observation remained statistically significant after adjustment for presence of abscess, fever, or leukocytosis; infection size; diabetes; patient age; and study medication received. The fnbA, cna, sdrC, map-eap, sed, seg, sei, sej, SCCmec type IV, and agr group II genes were also associated with clinical response (P < 0.05). This contemporary, international study demonstrates that pvl was not the primary determinant of outcome in patients with MRSA cSSSI.