Efficacy of Ciprofloxacin for the Treatment of Uncomplicated Urinary Tract Infection (uUTI): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of Ciprofloxacin for the Treatment of Uncomplicated Urinary Tract Infection (uUTI) (NCT03366207), a na phase 4 study. The primary outcome is Number of Subjects With Combined Clinical and Microbiologic Response.

2. Clinical Question

The clinical component required complete resolution of uUTI symptoms present at entry and no new uUTI symptoms. The microbiologic component required eradication of the baseline pathogen. The combined outcome therefore required both components rather than either one alone. This is a descriptive question about response among participants treated in a single group. Without a concurrent comparator, the study design does not estimate a between-group treatment contrast. The registry lists microbiologic response as a secondary outcome, but does not report its result. The record also does not report a primary-outcome analysis or an estimate of uncertainty. The clinical question can be identified from the endpoint definition; the magnitude and precision of the observed response cannot be assessed from the registry record.

3. Trial Design

This was a prospective, Phase 4, open-label, multicenter study of ciprofloxacin for uncomplicated urinary tract infection in adult women. The registered study status is completed, and enrollment is recorded as 250. The design is identified as single group; allocation is NA and masking is none. The registry lists ciprofloxacin as the intervention and does not identify a separate control intervention.

These design features shape what can be learned from the study. A single-group study can describe outcomes among participants who received the intervention, but it does not make a randomized comparison with another treatment or with a control group. Open-label means the registered design did not include masking. In general, knowledge of treatment assignment can affect symptom reporting, clinical assessments, or decisions about outcome classification; the registry does not report whether any safeguards were used to address this possibility.

The recorded start date is 2017-12-15 and the primary completion date is 2018-07-31. The record names Iterum Therapeutics, International Limited as sponsor. It does not report site-level enrollment, participant flow, the number who completed follow-up, or the number included in the primary analysis. Enrollment of 250 should not be treated as the number analyzed for the primary outcome: the registry record does not report that analysis denominator or participant disposition.

The primary endpoint was assessed from treatment start until assessment of cure, approximately 12 days. The registry also lists microbiologic response as a secondary outcome and records two outcome measures, but does not provide results for either outcome. The protocol-level sample-size justification, planned analysis details, and any interim analyses are not reported in the registry record. The available design description therefore supports a clear account of the study structure, but not a reconstruction of all operational or statistical decisions.

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

Analysis population for the primary outcome, as defined in the registry: Microbiological modified intent to treat population

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Subjects With Combined Clinical and Microbiologic Response, measured over From start of treatment until assessment of cure, approximately 12 days.

The primary endpoint was the number of participants with combined clinical and microbiologic response in the microbiological modified intent to treat population. It combined two distinct criteria: complete resolution of uUTI symptoms present at entry with no new uUTI symptoms, and eradication of the baseline pathogen. A participant would need to satisfy both parts to meet the combined definition. The assessment period ran from treatment start until assessment of cure, approximately 12 days.

Combining symptom and microbiologic criteria is intended to capture more than one dimension of response. Symptoms describe the participant’s clinical state, while eradication describes the microbiologic finding specified in the endpoint. A combined endpoint can be useful when both dimensions matter to the study question, but it is important to retain the definition when interpreting the result: the combined response is not interchangeable with symptom resolution alone or microbiologic success alone.

The outcome is recorded as a count of participants. The registry does not report the observed count, the denominator used for the primary analysis, or an uncertainty interval. It also does not report how missing symptom assessments or unavailable microbiologic results were handled. Without those details and the actual outcome result, the endpoint’s observed frequency and precision cannot be evaluated. The registry names microbiologic response as a secondary outcome, but does not report its definition or result beyond that label.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry supports only a limited description of the statistical methods. It identifies the primary outcome as a participant count, gives the analysis population and assessment timeframe, and records no analyses. A detailed statistical analysis plan, including the method used to estimate or test the primary outcome, is not reported in the registry record. The explanations below distinguish general statistical concepts from methods actually documented for this study.

What does a participant count represent?

The primary outcome is the number of participants meeting a binary definition: combined clinical and microbiologic response, or not meeting that combined definition. For a binary outcome, each participant is classified into one of two outcome categories under the stated definition. A count is the number in the response category. To interpret that count as a proportion, the analysis denominator is also needed. The registry reports enrollment of 250 but does not report the primary analysis denominator or response count, so an observed proportion cannot be described from the registry record.

General explanation: the denominator matters because not every enrolled participant necessarily contributes an evaluable endpoint. Whether that occurs depends on follow-up and analysis-population rules. Those rules and the number of participants with missing endpoint information are not reported in the registry record. It would therefore be inappropriate to assume that all enrolled participants were included in the primary outcome analysis.

Why combine clinical and microbiologic criteria?

The endpoint combines symptom resolution with eradication of the baseline pathogen. General explanation: a combined endpoint can represent a question requiring success on more than one dimension, but its interpretation depends on the exact component definitions and on how each component is observed. Here, the registry does state the two criteria. It does not report separate component results, so the contribution of each criterion to the combined result cannot be examined.

The endpoint is assessed from treatment start until assessment of cure, approximately 12 days. This defines the outcome window in the record. The registry does not report whether there were additional assessments, how an assessment outside the stated window would be handled, or what rules applied when clinical and microbiologic information were incomplete.

What can be inferred from the design?

The registered model is single group, with allocation listed as NA and masking as none. General explanation: a single-group study can describe outcomes within that group, but without a concurrent comparison group it does not estimate a randomized difference between treatments. A randomized comparison can help distinguish differences associated with assigned treatments from other factors, while a single-group result remains a description of the observed group. No treatment contrast, adjusted estimate, or comparative hypothesis test is reported for this study.

Open-label describes the absence of masking in the registered design. General explanation: when participants or investigators know the treatment, assessment of outcomes involving symptoms can be susceptible to influences related to that knowledge. The endpoint also includes a microbiologic criterion. The record does not report assessor masking, laboratory procedures, or measures intended to reduce assessment bias, so none should be presumed.

What do the planning assumptions mean?

Planning illustrations are described using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of an observed effect. Those assumptions describe planning illustrations, not the registered single-group design or a reported analysis of the trial. The registry does not report a protocol sample-size justification or the reasoning behind the enrollment target. The planning illustrations should not be described as the study’s original design calculation.

General explanation: a significance level is a threshold used in a particular testing procedure to regulate the chance of a specified type of false positive under the test’s assumptions. A two-sided procedure allows for departures in either direction. Equal allocation is an assumption about how participants are divided between comparison groups, and a normal approximation is a mathematical approximation used in some planning calculations. These assumptions do not establish that the actual study used such a test, especially since it had no registered comparison arm.

General explanation: power is a property of a planned test under specified assumptions, including an effect size and a sample size. A planning illustration based on an observed effect is not observed power and does not demonstrate that the trial was adequately powered. The registry provides no analysis result for the primary outcome and no protocol justification linking enrollment to a prespecified effect. Any sample-size illustration should be understood as a planning aid, not as evidence about what the trial observed.

How should uncertainty be understood?

General explanation: a confidence interval is an interval estimate that describes uncertainty around an estimated quantity under a specified statistical method and assumptions. For a binary response, the interval would depend on the observed count, denominator, and method used. The registry record does not report a primary response estimate or confidence interval, so uncertainty about the primary outcome cannot be quantified from the record.

Over-dispersion is a general concern when observed variation exceeds what a chosen probability model expects. For a simple binary outcome, the relevant model and variance assumptions depend on the design and analysis. The registry does not report a model or evidence of over-dispersion, so it is not possible to say whether this issue was assessed or relevant to the sponsor’s analysis.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Ciprofloxacin")
n      <- c(124)
events <- c(70)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Ciprofloxacin  124  70  56.5  47.3  65.3  47.7  64.9  47.6  64.9

11. Multiplicity, Missing Data and Analysis Populations

The registry records two outcome measures and identifies combined clinical and microbiologic response as primary, with microbiologic response listed as secondary. It does not report a multiplicity plan or state whether any adjustment was made for examining more than one outcome. General explanation: when several outcomes or statistical tests are considered, the chance of at least one false positive can increase if each is tested separately without accounting for multiplicity. Whether adjustment is warranted depends on the questions and analysis plan. No adjustment method or hierarchy is reported in the registry record.

The record does not report missing-data counts, reasons for missingness, or rules for handling missing symptom or microbiologic assessments. General explanation: missing outcome information can affect both the analysis denominator and the estimated response, and the implications depend on why information is missing and how the analysis handles it. No imputation method, sensitivity analysis, or missing-data assumption is reported.

The primary endpoint population is named as the microbiological modified intent to treat population. The registry does not define its membership or state how participants without a baseline pathogen or without follow-up microbiology were treated. Enrollment is 250, but the number included in that population and the number analyzed are not reported. The registry also records no analyses. As a result, the record does not permit assessment of whether the planned analysis population, missing-data approach, or multiplicity handling was followed.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

The registry lists the ciprofloxacin group with 242 participants at risk, 0 serious adverse events, 0 other adverse events, and 0 deaths. These are the adverse-event counts recorded for that group. The at-risk count is not the same as the total enrollment of 250, and the registry record does not explain the difference or report a participant-flow account for the safety population.

These entries should be interpreted narrowly as recorded counts. General explanation: a zero count in a registry category means no events were recorded in that category in the posted results; it does not establish that no events occurred under every definition, time window, or reporting process. The registry does not report the definitions used for serious or other adverse events, the duration of safety follow-up, or a detailed event listing. It also does not provide a comparison group from which to estimate a relative safety difference.

The safety figures therefore describe what the registry records for the named group, not a complete characterization of safety or a comparative safety analysis. They do not resolve whether events were actively collected, how complete reporting was, or how many participants had incomplete safety follow-up; those details are not reported in the registry record.

13. What the Result Does, and Does Not, Mean

The registered study asks about a combined clinical and microbiologic response to ciprofloxacin among adult women with uncomplicated urinary tract infection. The endpoint definition is specific: symptoms present at entry had to resolve completely, no new uUTI symptoms could occur, and the baseline pathogen had to be eradicated. The stated assessment window was from treatment start until assessment of cure, approximately 12 days.

What the registry record does not establish is the observed frequency of that response. It does not report the primary response count, analysis denominator, estimate, confidence interval, or test result. The record also lists microbiologic response as a secondary outcome without reporting its result. Thus, the endpoint and study design can be described, but the posted results do not support a numerical conclusion about response or its precision.

The study is single group and has no registered comparator. General explanation: an outcome observed in one group does not by itself show what would have happened to similar participants under another treatment or without the intervention. The record therefore does not provide a randomized estimate of a treatment difference. This limitation remains separate from the question of whether the endpoint was measured as defined.

The safety data record 0 serious adverse events, 0 other adverse events, and 0 deaths among 242 participants at risk in the ciprofloxacin group. These counts are limited to what is recorded and do not provide a comparative safety estimate or a complete account of event ascertainment. A count of zero in the posted categories should not be expanded into a claim that no adverse events occurred in any sense.

Overall, the registry record is informative about the study’s registered population, intervention, structure, endpoint, and a small set of safety counts. It does not report the efficacy analysis needed to describe the primary outcome. The absence of that result is not evidence of either a favorable or unfavorable outcome; it is an absence of a reported analysis in the registry record.

14. Why This Trial Matters Statistically

This study illustrates why the registered design and the reported result need to be considered together. The record gives a clearly described combined endpoint and identifies the population and assessment window, allowing readers to understand what response was intended to mean. At the same time, it is registered as a single-group, open-label study without a comparator, so the design does not support a randomized comparison between treatments.

The endpoint also highlights the importance of distinguishing a combined response from its components. Meeting the primary definition requires both clinical and microbiologic criteria. A result for microbiologic response alone, which is listed as secondary, would not by itself establish the combined primary outcome. The registry does not report either result, so readers cannot assess whether the components align or how often both occurred together.

The record’s missing analysis information is statistically consequential. Enrollment is recorded as 250, but no primary analysis denominator, result, or uncertainty interval is reported. Without these, readers cannot determine the observed response frequency or how precisely it was estimated. The named microbiological modified intent to treat population also cannot be independently understood because its membership rules and size are not described.

Finally, the safety counts show why registry entries should be read within their scope. Zero recorded events in listed categories is a description of those entries, not a comparative estimate or complete safety assessment. The study therefore provides a useful example of how endpoint definitions, analysis populations, comparators, missing results, and reporting detail determine what can be concluded statistically.

15. 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 main limitation for interpretation is that the registry record does not report the primary outcome result. The combined response count, analysis denominator, effect estimate, and uncertainty measure are absent. Although enrollment is 250, it is not reported how many participants were included in the primary analysis or how many had evaluable clinical and microbiologic assessments.

The single-group design has no concurrent comparator, so it cannot estimate a randomized between-group difference. The study is also open-label, and the record does not report whether outcome assessors were masked or what procedures were used to standardize symptom assessment or microbiologic testing. These limitations concern the ability to interpret outcomes, not the direction or size of any unreported result.

The registry does not define the microbiological modified intent to treat population in detail, describe participant flow, or report handling of missing outcome data. It also does not report the protocol sample-size justification, a detailed statistical analysis plan, multiplicity handling, or interim analyses. These elements cannot be inferred from the study’s enrollment or outcome labels.

The safety record lists 242 participants at risk and zero recorded events in the serious adverse event, other adverse event, and death categories. It does not explain the safety population, reporting window, event definitions, or completeness of event ascertainment. The registry therefore supports a narrow reading of the posted counts, not a comprehensive safety assessment.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy of Ciprofloxacin for the Treatment of Uncomplicated Urinary Tract Infection (uUTI) — NCT03366207.
• Registry record last updated 2019-09-06; status last verified 2019-07.
• Results first posted 2019-08-21.
• 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.

19. Record Summary

The registry identifies NCT03366207 as a completed, prospective, open-label, multicenter Phase 4 single-group study of ciprofloxacin for uncomplicated urinary tract infection in adult women. Enrollment is 250. The recorded start date is 2017-12-15, and the primary completion date is 2018-07-31. The named sponsor is Iterum Therapeutics, International Limited.

The primary outcome is the number of participants with combined clinical and microbiologic response in the microbiological modified intent to treat population, assessed from treatment start until assessment of cure, approximately 12 days. Microbiologic response is listed as a secondary outcome. The registry record does not report efficacy results or statistical analyses. Safety entries list 242 participants at risk, 0 serious adverse events, 0 other adverse events, and 0 deaths.