This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Efficacy and Safety Study of Eravacycline Compared With Ertapenem in Participants With Complicated Urinary Tract Infections (NCT03032510), a randomized phase 3 study. The primary outcome is Proportion of Participants in the Micro-ITT Population Demonstrating Clinical Cure and Microbiologic Success at the EOI Visit.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03032510 |
| Phase | Phase 3 |
| Condition | Complicated Urinary Tract Infections |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 1205 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Tetraphase Pharmaceuticals, Inc |
| Results posted | Yes |
2. Clinical Question
Population
The primary outcome population was micro-ITT: participants in the ITT population with at least 1 baseline bacterial pathogen from a urine or blood culture that caused a urinary tract infection and against which eravacycline and ertapenem had expected antibacterial activity. This is a narrower, microbiologically defined population than the ITT population. The registry record does not report the number of participants in the micro-ITT population.
Intervention
The experimental treatment was intravenous eravacycline. The trial title and outcome description identify eravacycline as the treatment being assessed. The arm label also mentions oral levofloxacin, but the arm description is blank, so the registry record does not provide further details about that component.
Comparator
The comparator was intravenous ertapenem. Its arm label also mentions oral levofloxacin, while the arm description is blank. The registry record does not report additional details about the comparator regimen in that description.
Primary question
The clinical question was whether eravacycline was non-inferior to ertapenem on a responder outcome in the micro-ITT population. A responder had to meet both parts of the endpoint: clinical cure and microbiological success at the end-of-infusion visit. The registry record identifies this as a co-primary outcome measure for the FDA, but does not report the comparative result, confidence interval, or non-inferiority margin.
3. Trial Design
The registry record describes a phase 3, randomized, double-blind, double-dummy, multicenter, prospective study comparing intravenous eravacycline with intravenous ertapenem for complicated urinary tract infections. The masking field says quadruple, the allocation is randomized, and the model is parallel. The study status is completed. Enrollment is recorded as 1205.
The trial began in 2017-01, and primary completion is recorded as 2017-12. Tetraphase Pharmaceuticals, Inc is listed as the sponsor. The stated purpose was to assess efficacy, safety, and pharmacokinetics of eravacycline compared with ertapenem in participants with complicated urinary tract infections.
The registry’s intervention list includes eravacycline, ertapenem, placebo, and levofloxacin. The arm labels name intravenous eravacycline or intravenous ertapenem with oral levofloxacin, but the arm descriptions are blank. The official title describes a double-dummy design; the record does not provide more detail about how the listed drugs were used in that design. It also does not report the treatment duration or the timing of study visits beyond the primary outcome’s end-of-infusion timeframe.
Randomization is intended to support a fair comparison by assigning participants to treatment groups in a way that does not depend on their measured characteristics. Masking can reduce the influence of treatment knowledge on care, outcome assessment, or reporting. Those are general design aims, not evidence that all potential sources of bias were eliminated in this trial. Details of randomization procedures and masking implementation are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Eravacycline (Intravenous)/Levofloxacin (Oral) | Ertapenem (Intravenous)/Levofloxacin (Oral) |
|---|---|---|
| STARTED | 603 | 602 |
| COMPLETED | 576 | 584 |
| NOT COMPLETED | 27 | 18 |
Reasons for not completing this period:
| Reason | Eravacycline (Intravenous)/Levofloxacin (Oral) | Ertapenem (Intravenous)/Levofloxacin (Oral) |
|---|---|---|
| Adverse Event | 5 | 2 |
| Lost to Follow-up | 8 | 7 |
| Withdrawal by Subject | 8 | 7 |
| Subject noncompliance | 4 | 2 |
| Physician Decision | 2 | 0 |
Analysis population for the primary outcome, as defined in the registry: micro-ITT included all participants in the ITT population who had at least 1 baseline bacterial pathogen from a urine or blood culture that caused a urinary tract infection (UTI) against which eravacycline and ertapenem had expected antibacterial activity.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Eravacycline (Intravenous)/Levofloxacin (Oral) | Ertapenem (Intravenous)/Levofloxacin (Oral) | Total |
|---|---|---|---|---|
| Participants analysed | 603 | 602 | 1205 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 338 | 331 | 669 |
| Age, Categorical: >=65 years | Participants | 265 | 271 | 536 |
| Age, Continuous | years | 57.1 (SD 18.16) | 56.5 (SD 19.34) | 56.8 (SD 18.7) |
| Sex: Female, Male: Female | Participants | 330 | 343 | 673 |
| Sex: Female, Male: Male | Participants | 273 | 259 | 532 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 11 | 15 | 26 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 592 | 587 | 1179 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 | 1 | 3 |
| Race (NIH/OMB): White | Participants | 600 | 601 | 1201 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: Latvia | participants | 36 | 39 | 75 |
| Region of Enrollment: Austria | participants | 0 | 1 | 1 |
| Region of Enrollment: Romania | participants | 54 | 59 | 113 |
| Region of Enrollment: Hungary | participants | 56 | 66 | 122 |
| Region of Enrollment: United States | participants | 9 | 13 | 22 |
| Region of Enrollment: Ukraine | participants | 148 | 137 | 285 |
| Region of Enrollment: Georgia | participants | 33 | 40 | 73 |
| Region of Enrollment: Slovakia | participants | 18 | 13 | 31 |
| Region of Enrollment: Bulgaria | participants | 61 | 42 | 103 |
| Region of Enrollment: Estonia | participants | 21 | 20 | 41 |
6. Primary Endpoint
The registry lists the primary outcome as Proportion of Participants in the Micro-ITT Population Demonstrating Clinical Cure and Microbiologic Success at the EOI Visit, measured over End of Infusion.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is the proportion of participants in the micro-ITT population demonstrating clinical cure and microbiological success at the end-of-infusion visit. The registry describes it as a count of participants and identifies it as a co-primary outcome measure for the FDA. The responder definition requires both components; success on only one component is not enough to meet the stated responder definition.
Clinical cure means complete resolution or significant improvement of infection signs or symptoms. Microbiological success means reducing baseline pathogen levels to <10^4 colony-forming units/milliliter. Clinical outcomes could be cure, failure, or indeterminate/missing; microbiological outcomes were characterized as success, failure, or indeterminate/missing. Combinations other than clinical cure together with microbiological success were considered non-responder or indeterminate.
Combining clinical and microbiological response is intended to reflect both how the infection presents and whether the identified pathogen meets the specified microbiological criterion. This is a general rationale for a composite responder endpoint, not a claim that the endpoint captures every aspect of patient experience. The registry record does not report the observed response counts, group proportions, or comparative estimate for this endpoint.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives the primary endpoint definition and the trial’s stated non-inferiority objective, but it does not report the endpoint’s comparative results. It therefore does not establish from the posted results whether the non-inferiority objective was met. The record also does not give a confidence interval, a p-value, or the non-inferiority margin. Without those items, the size and precision of the treatment contrast and its relationship to the prespecified decision threshold cannot be evaluated from the registry record.
Non-inferiority is a specific statistical claim: the question is whether the results rule out an amount of worse outcome for the investigational treatment that exceeds a prespecified margin. This general explanation does not imply that such a margin or a successful test is reported for this trial. A point estimate alone would not establish non-inferiority; the uncertainty around the estimate and the margin are central to interpretation. Neither the estimate nor the margin is reported in the registry record.
The safety information gives counts of participants affected by serious and other adverse events, as well as deaths. In the intravenous eravacycline group, 11 participants are recorded with serious adverse events among 601 at risk, and 174 are recorded with other adverse events among 601 at risk; 3 deaths are reported. In the intravenous ertapenem group, 6 participants are recorded with serious adverse events among 600 at risk, and 52 are recorded with other adverse events among 600 at risk; 2 deaths are reported. These are descriptive counts, not a substitute for the missing primary efficacy comparison. They do not by themselves establish that a treatment caused an event or that a difference between groups is statistically reliable.
The registry lists serious-event terms with percentages, including cerebrovascular accident and aneurysm ruptured at 0.3%, and cardiorenal syndrome, haemorrhoids, Clostridium difficile colitis, and renal abscess at 0.2%. The record does not specify the group denominators or provide counts alongside these percentages in the listed terms. They should therefore be read as reported safety summaries rather than as a basis for comparing treatment-specific risks.
Overall, the registry supports a description of the study design, endpoint definition, and selected safety counts. It does not provide enough reported efficacy information to judge the primary non-inferiority result. A lack of a reported result is not evidence that the treatments were equivalent, nor is it evidence that they differed.
9. Statistical Methods Explained
The registry describes a randomized parallel-group trial and states that the primary objective was to demonstrate non-inferiority of eravacycline to ertapenem for a responder outcome. Those design features define the intended comparison. The detailed statistical methods used to analyze the endpoint are not reported in the registry record.
What does non-inferiority ask?
As a general statistical concept, a non-inferiority analysis asks whether the data are sufficiently precise to exclude a disadvantage larger than a prespecified acceptable margin. It is not the same question as whether two treatments have exactly equal effects. The margin determines what degree of difference would still be considered compatible with non-inferiority, so it needs a clear justification and must be specified before interpreting the results. The non-inferiority margin is not reported in the registry record.
A non-inferiority conclusion depends on the estimated contrast, its confidence interval, and the margin. A confidence interval describes a range of values compatible with the data under the statistical model and gives an indication of precision. In a non-inferiority setting, the interval must be considered in relation to the margin and the direction of the treatment contrast. The registry record does not report the confidence interval or the underlying comparative estimate for this endpoint. It also does not report a p-value or the decision rule used for the primary analysis.
Why define the responder outcome carefully?
The endpoint combines clinical and microbiological outcomes. The registry defines clinical cure as complete resolution or significant improvement of signs or symptoms, and microbiological success as reducing the baseline pathogen or pathogens to <10^4 colony-forming units/milliliter. Both conditions are required for a responder. This combined definition can be useful when the question concerns both a patient’s clinical course and a microbiological measure, but it also means that the result depends on how each component is assessed and on how indeterminate or missing assessments are handled. Those handling details are not reported in the registry record.
The population is also part of the endpoint definition. The micro-ITT population includes participants in the ITT population with at least 1 qualifying baseline bacterial pathogen from a urine or blood culture. General interpretation of a treatment effect should therefore be tied to that population, rather than assumed to apply unchanged to every participant enrolled. The number included in the micro-ITT analysis and the disposition of participants across analysis populations are not reported in the registry record.
What can the safety counts establish?
Counts of participants with adverse events describe how many were recorded as affected in each group. A risk denominator provides context for such counts, but a descriptive count alone does not explain whether an event was caused by treatment, whether events differed in severity or duration, or whether a group contrast is compatible with random variation. Those questions generally require event definitions, comparison methods, and uncertainty estimates. The registry record gives group counts for serious adverse events, other adverse events, and deaths, but does not report comparative estimates or confidence intervals for them.
The serious-event terms are accompanied by percentages, but the listed terms do not include counts or an explicit denominator in the record. A percentage without a stated denominator cannot, by itself, support a transparent reconstruction of event counts or a treatment-group comparison. The percentages are best retained as reported rather than converted into new estimates.
How should planning illustrations be read?
The registry’s sample-size assumptions describe planning illustrations based on the observed effect, not the trial’s own design. They use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. Such calculations illustrate how a hypothetical future study’s required size can depend on its target effect and assumptions. They are not observed power and do not establish whether the completed trial was adequately powered. The sample-size justification for this trial is not reported in the registry record.
In general, a planning calculation is conditional on its assumptions, including the effect size chosen, outcome variability or event frequency, allocation, and analysis method. If the assumed effect differs from the effect a future study needs to detect, the planning result may not be useful for that purpose. The registry does not report the trial’s original design calculation, the assumptions used for it, or whether any design assumptions changed.
What analysis details remain unknown?
The registry record does not report the statistical model or test used for the primary endpoint, covariate adjustment, confidence-interval construction, missing-data methods, or analysis-set rules beyond the stated micro-ITT definition. It lists 3 outcome measures and 0 analyses. These omissions prevent an independent assessment of the primary analysis from the registry record alone. They should not be filled in by assuming that common methods were used.
10. Multiplicity, Missing Data and Analysis Populations
The primary outcome is described as a co-primary outcome measure for the FDA, and the registry also lists a secondary outcome concerning favorable clinical outcomes in the ITT population at the test-of-cure visit. The record lists 3 outcome measures overall, but it does not provide results for the primary endpoint or a full account of the other outcome analyses. A multiplicity strategy for interpreting multiple outcomes or co-primary measures is not reported in the registry record.
Multiplicity matters because evaluating several outcomes can increase the chance of a nominally notable result arising by chance. General approaches include adjusting the decision threshold or defining a testing sequence in advance. The registry does not state whether any such approach was used, so no conclusion about control of multiplicity can be drawn from this record.
The endpoint definition allows indeterminate or missing clinical and microbiological responses, and the description says combinations other than cure plus success were considered non-responder or indeterminate. It does not specify how indeterminate outcomes were handled in the analysis, how missing observations were distinguished from indeterminate results, or whether any imputation or sensitivity analyses were performed. Those methods are not reported in the registry record.
The micro-ITT population is defined by baseline culture evidence and expected antibacterial activity against the pathogen. The number of participants meeting that definition and the rules for handling participants without evaluable follow-up are not reported. The registry also does not provide a detailed accounting of participants included in the ITT, micro-ITT, or safety analyses. Consequently, the reported safety denominators should not be treated as the denominator for the primary efficacy analysis.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Eravacycline (Intravenous) | 11 | 601 | 1.8% |
| Ertapenem (Intravenous) | 6 | 600 | 1.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Eravacycline (Intravenous) | 3 of 601 |
| Ertapenem (Intravenous) | 2 of 600 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Eravacycline (Intravenous) | 174 of 601 |
| Ertapenem (Intravenous) | 52 of 600 |
Most frequent serious adverse event terms
| Event term | Organ system | Eravacycline (Intravenous) | Ertapenem (Intravenous) |
|---|---|---|---|
| Aneurysm ruptured | Vascular disorders | 2 of 601 | 1 of 600 |
| Cerebrovascular accident | Nervous system disorders | 2 of 601 | 0 of 600 |
| Acute myocardial infarction | Cardiac disorders | 1 of 601 | 0 of 600 |
| Cardiorenal syndrome | Cardiac disorders | 0 of 601 | 1 of 600 |
| Myocardial infarction | Cardiac disorders | 1 of 601 | 0 of 600 |
| Diarrhoea | Gastrointestinal disorders | 1 of 601 | 0 of 600 |
| Haemorrhoids | Gastrointestinal disorders | 0 of 601 | 1 of 600 |
| Ileus | Gastrointestinal disorders | 1 of 601 | 0 of 600 |
| Drug hypersensitivity | Immune system disorders | 1 of 601 | 0 of 600 |
| Clostridium difficile colitis | Infections and infestations | 0 of 601 | 1 of 600 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Eravacycline (Intravenous) | Ertapenem (Intravenous) |
|---|---|---|---|
| Nausea | Gastrointestinal disorders | 84 of 601 | 10 of 600 |
| Vomiting | Gastrointestinal disorders | 31 of 601 | 4 of 600 |
| Diarrhoea | Gastrointestinal disorders | 18 of 601 | 17 of 600 |
| Headache | General disorders | 17 of 601 | 18 of 600 |
| Infusion site phlebitis | General disorders | 24 of 601 | 3 of 600 |
Serious events with the highest arm-level rate: cerebrovascular accident (0.3%), aneurysm ruptured (0.3%), cardiorenal syndrome (0.2%), haemorrhoids (0.2%), clostridium difficile colitis (0.2%).
The registry records serious adverse events for 11 participants among 601 at risk in the intravenous eravacycline group, and for 6 participants among 600 at risk in the intravenous ertapenem group. Other adverse events are recorded for 174 participants among 601 at risk in the eravacycline group and 52 participants among 600 at risk in the ertapenem group. The record reports 3 deaths in the eravacycline group and 2 in the ertapenem group.
These figures are descriptive. They do not show whether an event was judged related to treatment, how long it lasted, or how severe it was beyond the serious-event classification. Nor do the counts alone quantify the uncertainty in a group comparison. The registry record does not report comparative safety estimates or confidence intervals.
The listed serious-event terms include cerebrovascular accident and aneurysm ruptured, each reported as 0.3%, and cardiorenal syndrome, haemorrhoids, Clostridium difficile colitis, and renal abscess, each reported as 0.2%. The record does not give group-specific denominators or counts for these terms, so the percentages should not be used to infer a treatment-group difference. These summaries are not evidence on their own of a causal relationship between a treatment and an event.
12. What the Result Does, and Does Not, Mean
The record establishes that this was a completed, randomized, masked phase 3 trial comparing intravenous eravacycline with intravenous ertapenem for complicated urinary tract infections. It also gives a specific responder endpoint and the clinical and microbiological criteria used to define it. These details explain the intended question and the type of outcome the study was designed to assess.
The record does not report the primary endpoint’s observed response counts, comparative estimate, confidence interval, or non-inferiority margin. As a result, it does not allow a reader to determine whether the stated non-inferiority objective was met or how precise the treatment comparison was. Absence of those results from the registry record should not be interpreted as evidence for equivalence, non-inferiority, superiority, or inferiority.
The adverse-event and death counts are useful as descriptive safety information, but they do not replace a comparative analysis. They do not establish cause, and the record does not provide uncertainty estimates for the treatment-group comparisons. The term-level percentages are not accompanied by group-specific denominators or counts.
More generally, a trial result is interpreted in light of its population, endpoint definitions, analysis methods, missing-data handling, and uncertainty. The registry reports the micro-ITT population definition but not its size or the primary analysis methods. It also does not report the non-inferiority margin or multiplicity approach. These gaps limit what can be concluded from the record, even though the study design and endpoint definitions are described.
The statistical meaning is therefore bounded: the registry record documents the comparison that was planned and selected safety counts, but the principal comparative efficacy result is not reported. No treatment recommendation follows from these registry entries alone.
13. Why This Trial Matters Statistically
This trial illustrates how a non-inferiority question differs from a simple search for a statistically significant difference. The stated objective was to assess whether eravacycline was non-inferior to ertapenem on a responder outcome in the micro-ITT population. Interpreting that question requires the estimated treatment contrast, its precision, and the prespecified margin. The registry record identifies the objective but does not report those elements.
The endpoint also demonstrates that an outcome definition is not merely a label. A responder had to meet both the clinical-cure criterion and the microbiological-success criterion at the end-of-infusion visit. The population was restricted by baseline culture evidence and expected activity of both treatments against the qualifying pathogen. These choices define which participants and outcomes inform the intended comparison.
Masked randomized designs can help limit bias in treatment assignment and outcome assessment, while a parallel-group structure supports a direct comparison between assigned groups. These are general design strengths, not guarantees against all bias. Details about implementation and analysis are not reported in the registry record, so the design labels should not be mistaken for a complete methodological account.
The record further shows why efficacy and safety summaries need to be distinguished. Adverse-event counts and deaths are reported, while the primary efficacy result is not. Descriptive safety data can inform what was recorded, but cannot answer the non-inferiority question. Keeping those forms of evidence separate avoids treating an available safety count as a substitute for an unreported efficacy estimate.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The principal limitation of the registry record for statistical interpretation is that it does not report the primary endpoint’s comparative results. Response counts, a treatment-effect estimate, a confidence interval, a p-value, and the non-inferiority margin are not reported. Without these, the primary objective cannot be evaluated from the record.
The record defines the micro-ITT population but does not give its size or a participant accounting for the efficacy analysis. It also does not report the statistical model or test, analysis-set rules beyond the stated population definition, missing-data methods, or sensitivity analyses. Although the endpoint description recognizes indeterminate or missing responses, how these were treated analytically is not reported in the registry record.
The registry lists safety counts, but does not provide comparative uncertainty estimates or details sufficient to interpret causal attribution. Serious-event term percentages are not paired with group-specific denominators or counts. The reported adverse-event figures therefore have descriptive value but limited scope for assessing between-group differences.
Several design details are also absent from the registry record. The arm descriptions are blank despite labels that mention oral levofloxacin, and the record does not detail treatment implementation, allocation procedures, or masking procedures. A sample-size justification and detailed statistical analysis plan are not reported. The planning assumptions listed in the registry are illustrations based on the observed effect, rather than documentation of the trial’s original design calculation.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy and Safety Study of Eravacycline Compared With Ertapenem in Participants With Complicated Urinary Tract Infections — NCT03032510.
- Registry record last updated 2022-01-06; status last verified 2021-12.
- Results first posted 2019-10-02.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a completed phase 3 randomized, double-blind, double-dummy, multicenter, prospective, parallel-group comparison of intravenous eravacycline and intravenous ertapenem for complicated urinary tract infections. Enrollment is recorded as 1205. The study began in 2017-01, with primary completion in 2017-12, and Tetraphase Pharmaceuticals, Inc is listed as sponsor.
The primary outcome is clinical cure together with microbiological success at the end-of-infusion visit in the micro-ITT population. The registry identifies it as an FDA co-primary outcome measure and states a non-inferiority objective. It does not report the primary comparative result, confidence interval, or non-inferiority margin. Safety counts include serious adverse events, other adverse events, and deaths in each treatment group; the record does not report comparative safety estimates.