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Clinical efficacy of ZERBAXA® (ceftolozane and tazobactam) against HABP/VABP

Treatment of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP)

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Study design

ZERBAXA was studied in critically ill patients.1

ASPECT-NP Study Design for ZERBAXA® (ceftolozane and tazobactam)

Primary efficacy endpoint: all-cause mortality at day 28. Objective was to demonstrate the noninferiority of ZERBAXA versus meropenem in adults with HABP/VABP. For analysis of the overall treatment differences, 2-sided 95% confidence intervals (Cls) were calculated as stratified Newcombe Cls.1

100% of patients in the trial were ventilated

Current antibiotic failure

Approximately 13% of patients were failing current antibacterial therapy for HABP/VABP

APACHE II score

Patients had a median baseline APACHE II score of 17, indicating a 24% mortality rate (1/3 of patients had a score of ≥20, a 40% estimated mortality)1,2

Hospitalized for ≥5 days

77% of patients had been hospitalized for ≥5 days, 92% in the ICU1

Primary endpoint

ZERBAXA achieved primary endpoint of noninferiority in day 28 all-cause mortality vs meropenem in adult patients with HABP/VABP in ITT population.1

ASPECT-NP Study Results: Day 28 All-Cause Mortality in the ITT Population With ZERBAXA® (ceftolozane and tazobactam) vs MeropenemASPECT-NP Study Results: Day 28 All-Cause Mortality in the ITT Population With ZERBAXA® (ceftolozane and tazobactam) vs Meropenem

The analysis population for the primary endpoint was the ITT population, which included all randomized patients.1

  • In the vHABP subgroup of patients (~28.5%), there was a favorable response for ZERBAXA in day 28 all-cause mortality.
    • ZERBAXA 24.2% (24/99) meropenem 37.0% (40/108)
  • In the VABP subgroup, day 28 all-cause mortality was 24.0% (63/263) for ZERBAXA and 20.3% (52/256) for meropenem

Kaplan-Meier for day 28 all-cause mortality including overall ITT population and subgroup analyses.

The Kaplan-Meier plots were not powered to demonstrate statistical significance in subgroups and individual time points. Subgroup analyses were not designed for noninferiority testing.1,3,4,5

Kaplan-Meier plots of day 28 all-cause mortality

overall ITT population1,3

Kaplan-Meier Overall ITT - Day 28 All-Cause Mortality Rates Were 87/362 (24%) for ZERBAXA® (ceftolozane and tazobactam)-Treated Patients vs 92/364 (25.3%) for Meropenem-Treated Patients for a Treatment Difference of 1.1% (95% CI -5.13, 7.39)

vHABP subgroup4

Kaplan-Meier vHABP Subgroup Day 28 All-Cause Mortality Rates Were 24/99 (24.2%) for ZERBAXA® (ceftolozane and tazobactam)-Treated Patients vs 40/108 (37%) for Meropenem-Treated Patients for a Treatment Difference of 12.8% (95% CI 0.18, 24.75)

VABP subgroup1,3

Kaplan-Meier VABP Subgroup Day 28 All-Cause Mortality Rates Were 63/263 (24%) for ZERBAXA® (ceftolozane and tazobactam)-Treated Patients vs 52/256 (20.3%) for Meropenem-Treated Patients for a Treatment Difference of -3.6% (95% CI -10.74, 3.52)

Subgroup of participants who failed prior antibiotic therapy in ASPECT-NP5,a

Kaplan-Meier Failed Prior Antibiotic Subgroup Day 28 All-Cause Mortality Rates Were 12/53 (22.6%) for ZERBAXA® (ceftolozane and tazobactam)-Treated Patients vs 18/40 (45%) for Meropenem-Treated Patients for a Treatment Difference of 22.4% (95% CI 3.1, 40.1)

aUnstratified Newcombe CIs; positive differences are in favor of ceftolozane/tazobactam; negative differences are in favor of meropenem.

Additional information and limitations for failed prior antibiotic therapy subgroup5: 

  • Participants who were failing prior antibacterial therapy were a prospectively defined subgroup.
  • Antibacterial therapy received 72 h prior to starting study treatment in participants who were failing antibacterial treatment before included: beta-lactam/BLI, fluoroquinolones, cephalosporins, aminoglycosides, macrolides, and carbapenems.
  • Participants with missing/indeterminate data were reported as deceased.

Outcomes in participants with failure of initial antibacterial therapy for hospital‑acquired/ventilator‑associated bacterial pneumonia prior to enrollment in the randomized, controlled phase 3 ASPECT‑NP trial of ceftolozane/tazobactam versus meropenem by Kollef et al. Critical Care (2022) 26:373 at https://doi.org/10.1186/s13054-022-04192-w, is licensed under Creative Commons 4.0 at http://creativecommons.org/licenses/by/4.0/

References

1. Kollef MH, Nováček M, Kivistik Ü, et al. Lancet Infect Dis. 2019;19(12):1299-1311.

2. APACHE II Calculator. Updated November 10, 2018. Accessed June 11, 2025. https://clincalc.com/lcuMortality/ APACHEll.aspx

3. Data available on request from the Merck National Service Center via email at daprequests@merck.com. Please specify information package US-ZER-01413.

4. Timsit JF, Huntington JA, Wunderink RG, et al. Crit Care. 2021;25:290.

5. Kollef MH, Timsit JF, Martin-Loeches I, et al. Crit Care. 2022;26(1):373.

View Mechanism of Action

INDICATIONS AND USAGE

  • ZERBAXA® (ceftolozane and tazobactam) is indicated for the treatment of adult patients (18 years and older) with hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP), caused by the following susceptible Gram-negative microorganisms: Enterobacter cloacae, Escherichia coli, Haemophilus influenzae, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and Serratia marcescens.
  • ZERBAXA is indicated for the treatment of adult and pediatric patients (birth to less than 18 years old) with complicated urinary tract infections (cUTI), including pyelonephritis, caused by the following susceptible Gram-negative microorganisms: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa.
  • ZERBAXA used in combination with metronidazole is indicated for the treatment of adult and pediatric patients (birth to less than 18 years old) with complicated intra-abdominal infections (cIAI) caused by the following susceptible Gram-negative and Gram-positive microorganisms: Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Bacteroides fragilis, Streptococcus anginosus, Streptococcus constellatus, and Streptococcus salivarius.

 

Usage

 

To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZERBAXA and other antibacterial drugs, ZERBAXA should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

IMPORTANT SAFETY INFORMATION

  • Patients with renal impairment: Decreased efficacy of ZERBAXA has been observed in patients with baseline CrCl of 30 to ≤50 mL/min. In a clinical trial of adult patients, patients with cIAIs with CrCl >50 mL/min had a clinical cure rate of 85.2% when treated with ZERBAXA plus metronidazole vs 87.9% when treated with meropenem. In the same trial, patients with CrCl 30 to ≤50 mL/min had a clinical cure rate of 47.8% when treated with ZERBAXA plus metronidazole vs 69.2% when treated with meropenem. A similar trend was also seen in the cUTI trial. Dose adjustment is required for adult patients with CrCl 50 mL/min or less. All doses of ZERBAXA are administered over 1 hour. Monitor CrCl at least daily in patients with changing renal function and adjust the dose of ZERBAXA accordingly.
  • Hypersensitivity: ZERBAXA is contraindicated in patients with known serious hypersensitivity to the components of ZERBAXA (ceftolozane/ tazobactam), piperacillin/tazobactam, or other members of the beta-lactam class. Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients receiving beta-lactam antibacterials. Before initiating therapy with ZERBAXA, make careful inquiry about previous hypersensitivity reactions to cephalosporins, penicillins, or other beta-lactams. If an anaphylactic reaction to ZERBAXA occurs, discontinue use and institute appropriate therapy.
  • Clostridioides difficile-associated diarrhea (CDAD), ranging from mild diarrhea to fatal colitis, has been reported with nearly all systemic antibacterial agents, including ZERBAXA. Careful medical history is necessary because CDAD has been reported to occur more than 2 months after the administration of antibacterial agents. If CDAD is confirmed, antibacterial use not directed against C. difficile should be discontinued, if possible.
  • Development of drug-resistant bacteria: Prescribing ZERBAXA in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and risks the development of drug-resistant bacteria.
  • Adverse reactions in adult patients with HABP/VABP: The most common adverse reactions occurring in ≥5% of adult patients receiving ZERBAXA in the HABP/VABP trial were hepatic transaminase increased (11.9%), renal impairment/renal failure (8.9%), and diarrhea (6.4%).
  • Adverse reactions in adult patients with cIAI or cUTI: The most common adverse reactions occurring in ≥5% of adult patients receiving ZERBAXA in the cUTI and cIAI trials were headache (5.8%) in the cUTI trial, and nausea (7.9%), diarrhea (6.2%), and pyrexia (5.6%) in the cIAI trial.
  • Adverse reactions in pediatric patients with cIAI or cUTI: The most common adverse reactions occurring in ≥7% of pediatric patients receiving ZERBAXA in the cIAI trial were diarrhea (17%), thrombocytosis (16%), pyrexia (13%), abdominal pain (11%), vomiting (10%), increased aspartate aminotransferase (7%), and anemia (7%). The most common adverse reactions occurring in ≥7% of pediatric patients receiving ZERBAXA in the cUTI trial were thrombocytosis (9%), leukopenia (8%), diarrhea (7%), and pyrexia (7%).
  • Pediatric Use: There is insufficient information to recommend dosage adjustment for pediatric patients younger than 18 years of age with cIAI and cUTI with eGFR 50 mL/min/1.73 m2 or less. ZERBAXA is not recommended in pediatric patients who have an eGFR 50 mL/min/1.73 m2 or less. Pediatric patients born at term or pre-term may not have an eGFR of 50 mL/min/1.73 m2 or greater at birth or within the first few months of life.

Before prescribing ZERBAXA, please read the accompanying Prescribing Information.

INDICATIONS AND USAGE
IMPORTANT SAFETY INFORMATION

  • ZERBAXA® (ceftolozane and tazobactam) is indicated for the treatment of adult patients (18 years and older) with hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia (HABP/VABP), caused by the following susceptible Gram-negative microorganisms: Enterobacter cloacae, Escherichia coli, Haemophilus influenzae, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, and Serratia marcescens.
  • ZERBAXA is indicated for the treatment of adult and pediatric patients (birth to less than 18 years old) with complicated urinary tract infections (cUTI), including pyelonephritis, caused by the following susceptible Gram-negative microorganisms: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa.
  • ZERBAXA used in combination with metronidazole is indicated for the treatment of adult and pediatric patients (birth to less than 18 years old) with complicated intra-abdominal infections (cIAI) caused by the following susceptible Gram-negative and Gram-positive microorganisms: Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Bacteroides fragilis, Streptococcus anginosus, Streptococcus constellatus, and Streptococcus salivarius.

 

Usage

 

To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZERBAXA and other antibacterial drugs, ZERBAXA should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

IMPORTANT SAFETY INFORMATION

  • Patients with renal impairment: Decreased efficacy of ZERBAXA has been observed in patients with baseline CrCl of 30 to ≤50 mL/min. In a clinical trial of adult patients, patients with cIAIs with CrCl >50 mL/min had a clinical cure rate of 85.2% when treated with ZERBAXA plus metronidazole vs 87.9% when treated with meropenem. In the same trial, patients with CrCl 30 to ≤50 mL/min had a clinical cure rate of 47.8% when treated with ZERBAXA plus metronidazole vs 69.2% when treated with meropenem. A similar trend was also seen in the cUTI trial. Dose adjustment is required for adult patients with CrCl 50 mL/min or less. All doses of ZERBAXA are administered over 1 hour. Monitor CrCl at least daily in patients with changing renal function and adjust the dose of ZERBAXA accordingly.
  • Hypersensitivity: ZERBAXA is contraindicated in patients with known serious hypersensitivity to the components of ZERBAXA (ceftolozane/ tazobactam), piperacillin/tazobactam, or other members of the beta-lactam class. Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients receiving beta-lactam antibacterials. Before initiating therapy with ZERBAXA, make careful inquiry about previous hypersensitivity reactions to cephalosporins, penicillins, or other beta-lactams. If an anaphylactic reaction to ZERBAXA occurs, discontinue use and institute appropriate therapy.
  • Clostridioides difficile-associated diarrhea (CDAD), ranging from mild diarrhea to fatal colitis, has been reported with nearly all systemic antibacterial agents, including ZERBAXA. Careful medical history is necessary because CDAD has been reported to occur more than 2 months after the administration of antibacterial agents. If CDAD is confirmed, antibacterial use not directed against C. difficile should be discontinued, if possible.
  • Development of drug-resistant bacteria: Prescribing ZERBAXA in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and risks the development of drug-resistant bacteria.
  • Adverse reactions in adult patients with HABP/VABP: The most common adverse reactions occurring in ≥5% of adult patients receiving ZERBAXA in the HABP/VABP trial were hepatic transaminase increased (11.9%), renal impairment/renal failure (8.9%), and diarrhea (6.4%).
  • Adverse reactions in adult patients with cIAI or cUTI: The most common adverse reactions occurring in ≥5% of adult patients receiving ZERBAXA in the cUTI and cIAI trials were headache (5.8%) in the cUTI trial, and nausea (7.9%), diarrhea (6.2%), and pyrexia (5.6%) in the cIAI trial.
  • Adverse reactions in pediatric patients with cIAI or cUTI: The most common adverse reactions occurring in ≥7% of pediatric patients receiving ZERBAXA in the cIAI trial were diarrhea (17%), thrombocytosis (16%), pyrexia (13%), abdominal pain (11%), vomiting (10%), increased aspartate aminotransferase (7%), and anemia (7%). The most common adverse reactions occurring in ≥7% of pediatric patients receiving ZERBAXA in the cUTI trial were thrombocytosis (9%), leukopenia (8%), diarrhea (7%), and pyrexia (7%).
  • Pediatric Use: There is insufficient information to recommend dosage adjustment for pediatric patients younger than 18 years of age with cIAI and cUTI with eGFR 50 mL/min/1.73 m2 or less. ZERBAXA is not recommended in pediatric patients who have an eGFR 50 mL/min/1.73 m2 or less. Pediatric patients born at term or pre-term may not have an eGFR of 50 mL/min/1.73 m2 or greater at birth or within the first few months of life.

Before prescribing ZERBAXA, please read the accompanying Prescribing Information.