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ATM-AVI

Phase 3

Complicated Intra-abdominal Infection | Small molecule | Infectious Disease |Pfizer, Inc.|Last Updated: Jul 1, 2026

Target and mechanism

ModalitySmall molecule

Also known as Part A: ATM-AVI Single Dose, Cohorts 1-4

Success Probability

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Market & Valuation

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Trial Design

RandomizedACTIVE_CONTROLLEDDMC
Total Trials1
Total Enrollment422

FDA Designations

No designations recorded

Clinical trial landscape

ATM-AVI · 3 trials · 5 indications

Phase 3 1Phase 2 2
NCT03329092A Study to Determine the Efficacy, Safety and Tolerability of Aztreonam-Avibactam (ATM-AVI) ± Metronidazole (MTZ) Versus Meropenem (MER) ± Colistin (COL) for the Treatment of Serious Infections Due to Gram Negative Bacteria.Complicated Intra-abdominal Infection
COMPLETED422 Analytics
PHASE3COMPLETED
A Study to Determine the Efficacy, Safety and Tolerability of Aztreonam-Avibactam (ATM-AVI) ± Metronidazole (MTZ) Versus Meropenem (MER) ± Colistin (COL) for the Treatment of Serious Infections Due to Gram Negative Bacteria.
Complicated Intra-abdominal InfectionUnlock trial analytics

Study Endpoints

Primary Endpoints

Percentage of Participants With Clinical Cure at Test of Cure (TOC) Visit: Intent-To-Treat (ITT) Analysis Set
At TOC visit (Day 28)

Clinical cure was defined as improvement in baseline signs and symptoms such that after study treatment, no further antimicrobial treatment for the index infection (i.e., cIAI or HAP/VAP) was required. Additionally, for cIAI participants, no unplanned drainage or surgical intervention was necessary since the initial procedure. Clinical cure was determined by the Independent Clinical Adjudication Committee. 95% confidence interval (CI) was based on Jeffrey's method.

Percentage of Participants With Clinical Cure at TOC Visit: Clinically Evaluable (CE) Analysis Set
At TOC visit (Day 28)

Clinical cure = improvement in baseline signs and symptoms such that after study treatment, no further antimicrobial treatment for the index infection (i.e., cIAI or HAP/VAP) was required. Additionally for cIAI participants, no unplanned drainage or surgical intervention was necessary since the initial procedure. Clinical cure was determined by Independent Clinical Adjudication Committee. 95% CI was based on Jeffrey's method. CE analysis set:all participants in ITT analysis set; met criteria for cIAI, or HAP/VAP; received at least 48 hours of study treatment or \<48 hours of treatment before discontinuing study drug due to AE; no concomitant antibiotics for any baseline pathogens between first dose and TOC (except protocol-allowed antibiotics); no prior antibiotics other than allowed per protocol; no important protocol deviations; no clinical outcome of indeterminate at TOC; no monomicrobial infections due to non-eligible pathogens and did not have only Gram-positive pathogens.

Maximum Predicted Plasma Concentration (Cmax) of ATM and AVI
Up to 15 Days

Cmax is the maximum plasma concentration of ATM and AVI as population pharmacokinetic (popPK) analysis predicts.

Minimum Predicted Trough Plasma Concentration (Cmin) of ATM and AVI
Up to 15 Days

Cmin is the minimum trough plasma concentration of ATM and AVI as popPK analysis predicts.

Area under the Concentration-Time Curve (AUC) of ATM-AVI
Up to 15 Days

AUC is a measure of the plasma concentration of ATM and AVI overtime as popPK analysis predicts.

Plasma Decay Half-Life (t1/2)
Up to 15 Days

Half-life is the time measured for the plasma concentration of ATM and AVI to decrease by one half as popPK analysis predicts.

Apparent Clearance (CL)
Up to 15 Days

ATM and AVI clearance is a quantitative measure of the rate at which ATM and AVI are removed from the blood (rate at which ATM and AVI are metabolized or eliminated by normal biological processes). Clearance obtained after intravenous infusion dose (apparent clearance) is influenced by the fraction of the dose absorbed.

Proportion of Participants reporting Adverse Events (AE)
Baseline up to Day 50

Proportion of participant AE reports of vital signs, physical examinations, and clinical laboratory tests overall and by age cohort. For each AE the last assessment made prior to the first dose of study drug will be defined as the baseline.

Proportion of Participants reporting Serious Adverse Events (SAE)
Baseline up to Day 50

Proportion of participant SAE reports of vital signs, physical examinations, and clinical laboratory tests overall and by age cohort. For each SAE the last assessment made prior to the first dose of study drug will be defined as the baseline.

Proportion of Participants reporting AEs leading to discontinuation
Baseline up to Day 50

Proportion of Participants reporting AEs leading to discontinuation from baseline. For each discontinuation the last assessment made prior to the first dose of study drug will be defined as the baseline

Proportion of Participants reporting AEs resulting in death
Baseline up to Day 50

Proportion of Participants reporting AE resulting in death from baseline. For each death the last assessment made prior to the first dose of study drug will be defined as the baseline

Proportion of Participants reporting liver injury and acute kidney injury of ATM-AVI relative to Best Available Therapy (BAT)
Baseline up to Day 50

Proportion of Participants reporting liver injury and acute kidney injury of ATM-AVI relative to Best Available Therapy (BAT) from baseline. For each report of liver and acute kidney injury the last assessment made prior to the first dose of study drug will be defined as the baseline

Plasma Concentration of Aztreonam (ATM): Sparse Sampling at Day 1, 0 hr
Predose (0 hr) on Day 1

All participants were to have sparse pharmacokinetics (PK) sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above lower limit of quantification (LLOQ). LLOQ for ATM was 0.1 microgram per milliliter (mcg/ml).

Plasma Concentration of Aztreonam (ATM): Sparse Sampling at Day 1, 0.42 hr
0.42 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentrations of Aztreonam (ATM): Sparse Sampling at Day 1, 3.25 hr
3.25 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentrations of Aztreonam (ATM): Sparse Sampling at Day 1, 5 hr
5 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 1, 0 hr
Predose (0 hr) on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 nanogram per milliliter (ng/ml).

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 1, 0.42 hr
0.42 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 1, 3.25 hr
3.25 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 1, 5 hr
5 hr Post dose on Day 1

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Aztreonam (ATM): Sparse Sampling at Day 4, 0 hr
Predose (0 hr) on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Sparse Sampling at Day 4, 2.75 hr
2.75 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Sparse Sampling at Day 4, 5 hr
5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 4, 0 hr
Predose (0 hr) on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 4, 2.75 hr
2.75 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Sparse Sampling at Day 4, 5 hr
5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration Aztreonam (ATM): Intensive Sampling at Day 4, 0 hr
Predose (0 hr) on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration Aztreonam (ATM): Intensive Sampling at Day 4, 0.5 hr
0.5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 1 hr
1 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 2 hr
2 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 3 hr
3 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 3.25 hr
3.25 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 3.5 hr
3.5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 3.75 hr
3.75 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 4 hr
4 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 5 hr
5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Aztreonam (ATM): Intensive Sampling at Day 4, 6 hr
6 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for ATM was 0.1 mcg/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 0 hr
Predose (0 hr) on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 0.5 hr
0.5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 1 hr
1 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 2 hr
2 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 3 hr
3 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 3.25 hr
3.25 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 3.5 hr
3.5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 3.75 hr
3.75 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 4 hr
4 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 5 hr
5 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Plasma Concentration of Avibactam (AVI): Intensive Sampling at Day 4, 6 hr
6 hr Post dose on Day 4

All participants were to have sparse PK sampling on Day 1; the first sequentially enrolled 25 participants in study were to have intensive PK sampling on Day 4 while the remaining participants were to have sparse sampling on Day 4. Data was summarized only for observations above LLOQ. LLOQ for AVI was 10 ng/ml.

Maximum Observed Plasma Concentration (Cmax) of Aztreonam (ATM): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4
Maximum Observed Plasma Concentration (Cmax) of Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4
Time of Observed Maximum Concentration (Tmax) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4
Area Under the Plasma Concentration Time Curve From Time Zero up to 6 Hours (AUC[0-6]) for Aztreonam (ATM): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

AUC(0-6) was defined as the area under the plasma concentration-time curve from time zero up to the six hours postdose.

Area Under the Plasma Concentration Time Curve From Time Zero up to 6 Hours (AUC[0-6]) for Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

AUC(0-6) was defined as the area under the plasma concentration-time curve from time zero up to the six hours postdose.

Area Under the Plasma Concentration Time Curve From Time Zero up to the Last Measured Concentration (AUC[0-last]) for Aztreonam (ATM): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

AUC(0-last) was defined as the area under the plasma concentration-time curve from time zero up to the time of the last measurable concentration.

Area Under the Plasma Concentration Time Curve From Time Zero up to the Last Measured Concentration (AUC[0-last]) for Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

AUC(0-last) was defined as the area under the plasma concentration-time curve from time zero up to the time of the last measurable concentration.

Time of Last Measured Concentration (Tlast) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4
Plasma Elimination Half-life (t1/2) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

Plasma elimination half-life was defined as time measured for the plasma concentration of ATM and AVI to decrease by one half of its initial concentration.

Apparent Volume of Distribution at Steady State (Vss) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

Apparent volume of distribution at steady state was defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug.

Volume of Distribution (Vz) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

Apparent volume of distribution was defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug.

Apparent Clearance (CL) of Aztreonam (ATM) and Avibactam (AVI): Intensive Sampling at Day 4
predose, 0.5 1, 2, 3, 3.25, 3.5, 3.75, 4, 5 and 6 hour postdose on Day 4

Clearance of a drug was measure of the rate at which a drug was metabolized or eliminated by normal biological processes.

Number of Participants With Treatment Emergent Adverse Events (AEs) and Serious Adverse Events (SAEs)
From first dose of study drug up to the LFU visit (up to maximum of 38 days)

An AE was any untoward medical occurrence in a participant who received investigational product without regard to possibility of causal relationship. SAEs was an AE resulting in any of the following outcomes: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly; or was an important medical event which may jeopardise the participants or require medical intervention to prevent one of the above outcomes. Treatment-emergent were events between first infusion of study drug and up to late follow-up (LFU) visit (20 to 24 days after last infusion). AEs included both non-serious AEs and SAEs.

Number of Participants With Electrocardiogram (ECG) Abnormalities
Baseline up to EOT (up to a maximum of 15 days)

Criteria for ECG abnormalities: QT value: greater than or equal to (\>=) 450 milliseconds (msec), \>=480 msec, \>=500 msec, \>=500 and increase from baseline \>=60 msec. Increase from baseline in QT: \>=30 msec, \>=60 msec. Decrease from baseline in QT: \>=30 msec, \>=60 msec. QTcB value: \>=450 msec, \>=480 msec, \>=500 msec, \>=500 and increase from baseline \>=60 msec. Increase from baseline in QT interval using Bazett's correction (QTcB) value: \>=30 msec, \>=60 msec. Decrease from baseline in QTcB: \>=30 msec, \>=60 msec. QT interval using Fridericia's correction (QTcF) value: \>=450 msec, \>=480 msec, \>=500 msec, \>=500 and increase from baseline \>=60 msec. Increase from baseline in QTcF value: \>=30 msec, \>=60 msec. Decrease from baseline in QTcF value: \>=30 msec, \>=60 msec. EOT (end of treatment) visit occurred within 24 hours after last infusion.

Number of Participants With Potentially Clinically Significant Laboratory Abnormalities in Hematology Parameters
Baseline up to LFU visit (up to maximum of 38 days)

Criteria for abnormality: Hemoglobin, hematocrit, erythrocytes less than(\<) 0.7\*lower limit of normal \[LLN\] and (\&) greater than (\>) 30 percent (%) below baseline \[BB\]; \>1.3\*upper limit of normal \[ULN\] \& \>30% above baseline \[AB\], leukocytes \<0.65\*LLN \& \>60% BB; \>1.6\* ULN \& \>100% AB; platelets \<0.65\*LLN \& \>50% BB; \>1.5\*ULN \& \>100% AB; neutrophils \<0.65\*LLN \& \>75% BB; \>1.6\*ULN \& \>100% AB, lymphocytes \<0.25\*LLN \& \>75%BB; \>1.5\*ULN \& \>100% AB, basophils, eosinophils, monocytes\>4.0\*ULN \& \>300% AB. LFU visit occurred within 20 to 24 days after last infusion.

Number of Participants With Potentially Clinically Significant Laboratory Abnormalities in Clinical Chemistry Paramteres
Baseline up to LFU visit (up to maximum of 38 days)

Criteria for abnormality: aspartate aminotransferase, alanine aminotransferase \>3.0\*ULN \& \>100% AB, alkaline phosphatase \<0.5 \*LLN \& \>80% BB\&; \>3.0\*ULN \& \>100% AB; bilirubin \>1.5\*ULN \& \>100% AB; direct bilirubin \>2.0\*ULN \& \>150% AB; protein \<0.5\*LLN \& \>50%BB; \>1.5\*ULN \& \>50% AB, albumin \<0.5\*LLN \& \>50% BB; \>1.5\*ULN \& \>50% AB, urea nitrogen \<0.2\* LLN \& \>100% BB; \>3.0\*ULN \& \>200% AB, creatinine \>2.0\*ULN \& \>100% AB, sodium \<0.85\*LLN \& \>10% BB;\>1.1\*ULN \&\>10% AB; potassium \<0.8\*LLN \&\>20% BB; \>1.2\*ULN \&\>20% AB, chloride \<0.8\*LLN \&\>20% BB;\>1.2\*ULN \& \>20% AB, calcium \<0.7\*LLN \& \>30% BB; \>1.3\*ULN \& \>30% AB, phosphate \<0.5\*LLN \& \>50% BB; \>3.0\*ULN \& \>200% AB, bicarbonate \<0.7\*LLN \& \>40% BB; \>1.3\*ULN \& \>40% AB, glucose \<0.6\*LLN \& \>40% BB, \>3.0\*ULN \& \>200% AB. LFU visit occurred within 20 to 24 days after last infusion.

Number of Participants With Clinically Significant Vital Signs
From first dose of study drug up to LFU visit (up to maximum of 38 days)

Vital sign parameters included: Supine systolic blood pressure (millimeters of mercury \[mmHg\]), Supine diastolic blood pressure (mmHg), Heart rate (beats per minute), Respiratory rate (breaths per minute) and body temperature (degree celsius). Criteria for clinical significance in vital signs was based on investigator's assessment. LFU visit occurred within 20 to 24 days after last infusion.

Number of Participants With Clinical Significant Physical Examination Findings : MITT Population
From first dose of study drug up to the LFU visit (up to maximum of 38 days)

Physical examinations included an assessment of abdomen, cardiovascular, general appearance, head, eyes, ears, nose, lymph nodes, skin, musculoskeletal, neurological, respiratory systems and other (edemas). Clinically significant abnormality in physical examination was based on investigator's assessment. LFU visit occured within 20 to 24 days after last infusion.

Secondary Endpoints

Percentage of Participants With Clinical Cure at TOC Visit: Microbiological Intent-To-Treat (Micro-ITT) Analysis Set
At TOC visit (Day 28)
Percentage of Participants With Clinical Cure at TOC Visit: Microbiologically Evaluable (ME) Analysis Set
At TOC visit (Day 28)
Percentage of Participants With Clinical Cure at TOC Visit by Type of Infection: ITT Analysis Set
At TOC visit (Day 28)
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Study Design & Arms

AllocationRANDOMIZED
MaskingSINGLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Aztreonam-Avibactam ± MetronidazoleEXPERIMENTALAll patients randomised to this arm will receive ATM-AVI; all patients with cIAI will receive MTZ for anaerobic cover
Meropenem ± ColistinACTIVE_COMPARATORAll patients randomised to this arm will receive MER; addition of COL will be at investigator's discretion in line with local practice
ATM-AVIEXPERIMENTALATM-AVI administered iv every 6 or 8 hours and dosed according to participant's weight and kidney function for up to 14 days depending on response. At the investigator's discretion, the participant may be switched to oral therapy after 3 days of iv ATM-AVI therapy
Best available therapy (BAT)ACTIVE_COMPARATORBAT will be selected by the investigator and administered iv. At the investigator's discretion, the participant may be switched to oral therapy after 3 days of iv BAT
ATM-AVI + MetronidazoleEXPERIMENTALAztreonam-avibactam + metronidazole

Interventions

NameTypeDescription
ATM-AVIDRUG(Creatinine clearance \> 50 mL/min) 6500 mg ATM/2167 mg (loading dose, extended loading dose and maintenance dose) by iv infusion on Day 1 followed by a total daily dose of 6000 mg ATM/2000 mg AVI (Creatinine clearance 31 - 50 mL/min) 4250 mg ATM/1417 mg AVI on Day 1 (loading dose, extended loading dose, maintenance dose) followed by total daily dose 3000 mg ATM/1000 mg AVI (Creatinine clearance 16 - 30 mL/min) 2700 mg ATM/900 mg AVI on Day 1 (loading dose, extended loading dose maintenance dose), followed by total daily dose 2025 mg ATM/675 mg AVI
MTZDRUGFor cIAI only; 500 mg/100 mL metronidazole iv infusion over 1hr q8h
MERDRUGWhere pathogen initially not suspected of being MER-resistant: (Creatinine clearance \> 50 mL/min) 1000 mg meropenem by 30 min iv infusion q8h (Creatinine clearance 26 - 50 mL/min) 1000mg meropenem by 30 min iv infusion q12h (Creatinine clearance 16 - 25 mL/min) 500 mg meropenem by 30 min iv infusion q12h Where pathogen initially suspected of being MER-resistant (Creatinine clearance \> 50 mL/min) 2000 mg meropenem by 180 min iv infusion q8h (Creatinine clearance 26 - 50 mL/min) 2000 mg meropenem by 180 min iv infusion q12h (Creatinine clearance 16 - 25 mL/min) 1000 mg meropenem by 180 min iv infusion q12h
COLDRUGLoading dose 9 million IU by 30 -60 min iv infusion (6 million IU where weight \< 60 kg) followed by one of the following maintenance doses: (Creatinine clearance \> 50 mL/min) after a 12h interval, commence maintenance dosing 9 million IU daily in 2 or 3 divided doses by 30 -60 min iv infusions. (Creatinine clearance 31 - 50 mL/min) After a 24 hr interval, commence maintenance dosing of 6 million IU daily in 2 divided doses by 30 -60 min iv infusion (Creatinine clearance 21 - 30 mL/min) After a 24 hr interval, commence maintenance dosing 5 million IU daily in 2 divided doses by 30 -60 min iv infusion (Creatinine clearance 16 - 20 mL/min) after a 24 hr interval, commence maintenance dosing 4 million IU daily in 2 divided doses by 30 -60 min iv infusion
BATDRUGBAT will be selected by the investigator and administered iv as appropriate for the selected drug(s)
MetronidazoleDRUGMetronidazole 500mg infused over 1 hour every 8 hours
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites157

Inclusion Criteria: All subjects: 1. Male or female from 18 years of age 2. Provision of informed consent 3. Confirmed diagnosis of HAP/VAP or cIAI requiring iv antibiotic treatment 4. Female patients are authorized to participate in this clinical study if criteria concerning pregnancy avoidance s...

Countries:United StatesArgentinaBulgariaChinaCroatiaCzechiaGreeceIndiaIsraelItalyMalaysiaMexicoPhilippinesRomaniaRussiaSouth KoreaSpainTaiwanThailandTurkey (Türkiye)UkraineHungaryFranceGermany
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Recent Changes (Last 90 Days)

LOWJul 2, 2026NCT05639647lastUpdatePostDate: changed
LOWJul 2, 2026NCT05639647lastUpdatePostDate: changed
LOWJul 2, 2026NCT05639647lastUpdatePostDate: changed
LOWJul 2, 2026NCT05639647lastUpdatePostDate: changed
LOWJun 11, 2026NCT05639647lastUpdatePostDate: changed
LOWJun 11, 2026NCT05639647lastUpdatePostDate: changed

Frequently asked questions about ATM-AVI

What is ATM-AVI used for?

ATM-AVI, also known as aztreonam-avibactam, is an investigational small molecule being developed for the treatment of complicated intra-abdominal infections (cIAIs) and serious infections due to Gram-negative bacteria, including hospital-acquired and ventilator-associated pneumonia. It is currently in Phase 2 and Phase 3 clinical trials.

How does ATM-AVI work?

ATM-AVI combines aztreonam, a monobactam antibiotic that inhibits bacterial cell wall synthesis, with avibactam, a beta-lactamase inhibitor that protects aztreonam from degradation by resistant bacteria. This combination is designed to target Gram-negative bacteria, including those producing certain beta-lactamases.

Who makes ATM-AVI?

ATM-AVI is being developed by Pfizer, Inc., a biopharmaceutical company listed on the New York Stock Exchange under the ticker symbol PFE. Pfizer is conducting multiple clinical trials to evaluate the drug's safety, tolerability, and efficacy in treating serious Gram-negative infections.

What phase is ATM-AVI in?

ATM-AVI is in Phase 2 and Phase 3 clinical development. It is an investigational drug and has not been approved by regulatory authorities. Clinical trials are ongoing to assess its use in complicated intra-abdominal infections and other serious Gram-negative bacterial infections.

What clinical trials is ATM-AVI in?

ATM-AVI is being studied in several trials, including NCT02655419 (REJUVENATE), a Phase 2 study in cIAIs; NCT03329092, a Phase 3 study comparing ATM-AVI to meropenem-based regimens; NCT05639647, a Phase 2 study in serious Gram-negative infections; and NCT06462235 (CHERISH), a Phase 2 study in infants and newborns.

Is ATM-AVI the same as aztreonam-avibactam?

Yes, ATM-AVI is the same as aztreonam-avibactam. The drug is also referred to as ATM-AVI in clinical trial documentation, and it is being investigated for the treatment of complicated intra-abdominal infections and other serious Gram-negative bacterial infections.