Clinical and Microbial Efficacy of Besifloxacin Ophthalmic Suspension, 0.6% in the Treatment of Bacterial Conjunctivitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical and Microbial Efficacy of Besifloxacin Ophthalmic Suspension, 0.6% in the Treatment of Bacterial Conjunctivitis (NCT01740388), a randomized phase 3 study. The primary outcome is Clinical Resolution.

2. Clinical Question

The registry describes a randomized, double-masked, parallel comparison. The clinical question is therefore about the number of participants meeting the stated definition of clinical resolution in each treatment group at the specified visit. This is a binary outcome at the participant level: each participant either meets the resolution definition or does not, provided the required assessment is available.

The brief summary also identifies microbial efficacy as an aim, and the listed secondary outcomes include microbial eradication. The registry record does not report the outcome counts or a treatment comparison for clinical resolution or microbial eradication. It therefore does not establish from the posted information how the groups differed on either outcome. The trial status is terminated, but the reason for termination is not reported in the registry record.

3. Trial Design

This is a Phase 3, randomized, double-masked, parallel-group trial sponsored by Bausch & Lomb Incorporated. It enrolled 136 participants with bacterial conjunctivitis. The trial compared besifloxacin ophthalmic suspension 0.6% with the vehicle of that suspension. Both regimens were administered twice daily for 3 days.

The primary outcome is named Clinical Resolution, assessed at Visit 2 (Day 4 or 5). Its stated definition requires the absence of both conjunctival discharge and bulbar conjunctival injection after treatment. Microbial eradication is listed among the secondary outcomes, along with clinical resolution. The registry lists six outcome measures, but an efficacy analysis is not reported in the registry record.

The record gives a start date of 2013-02 and a primary completion date of 2013-07. The trial status is terminated. The reason for termination, the full recruitment history, and details of any changes to the planned trial are not reported in the registry record. The enrollment figure describes the trial as a whole; it should not be read as evidence that every enrolled participant contributed data to every outcome.

Randomization assigns participants to groups by chance, while masking is intended to limit the influence of treatment knowledge on trial conduct or assessment. The record identifies the trial as randomized and double-masked, but does not describe the allocation procedure, who was masked, or how masking was maintained. The parallel model means the treatment groups are distinct rather than a crossover comparison, but details of the protocol beyond the listed design characteristics are not reported.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis population is only Subjects with non-missing data, Clinical Resolution (LOCF \[Last Observation Carried Forward\])

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 Clinical Resolution, measured over Visit 2 (Day 4 or 5).

The primary endpoint is Clinical Resolution at Visit 2 (Day 4 or 5). A participant meets the stated definition when both conjunctival discharge and bulbar conjunctival injection are absent after 3 days of treatment. Because the measure is recorded as a number of participants, it is a binary participant-level outcome summarized as a count of those meeting the definition.

Clinical signs provide a direct way to define whether the specified findings remain at the assessment visit. Requiring absence of both findings makes the endpoint a joint criterion: absence of only one sign is not enough to meet the definition. In general, a clearly specified binary endpoint can make group outcomes straightforward to count and compare, provided the assessment rules and analysis population are applied consistently.

The registry states that the analysis population includes only subjects with non-missing data for Clinical Resolution, using LOCF (Last Observation Carried Forward). That identifies a missing-data convention for this endpoint, but the record does not provide the counts of participants meeting the endpoint, the number assessed, or an estimate comparing the treatment groups. The registry also indicates that the primary outcome has several categories or time points and is not reduced to one comparison. Consequently, the posted record does not support a single numerical estimate of the treatment contrast for this endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary measure is a binary outcome: for each participant with an assessment, the endpoint definition is either met or not met. The registry expresses the outcome as a number of participants. In general, binary outcomes can be described with counts and proportions, and a comparison between randomized groups can estimate how often the endpoint occurred under each assigned regimen. The registry record does not provide the counts or a reported comparison for clinical resolution, so no treatment contrast can be interpreted from the posted outcome information.

What a group comparison would describe

In general, an unadjusted comparison uses the observed outcome data in the groups without accounting for other variables. An adjusted comparison may incorporate prespecified covariates or a model, but those choices depend on the analysis plan. The registry record does not report a model, adjusted estimates, or an analysis plan for the clinical-resolution comparison. It would therefore be inappropriate to attribute an unreported statistical method to the trial.

A confidence interval, in general, describes a range of estimates compatible with the observed data under the method used. Its width conveys precision: wider intervals indicate less precision, while narrower intervals indicate more precision. A p-value, in general, describes how compatible the observed data are with a specified null model; it does not measure the probability that a treatment works. Neither a confidence interval nor a p-value for the primary comparison is reported in the registry record.

Planning calculations are not trial results

Any sample-size illustrations use a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. They describe planning for a stated fraction of an observed effect. Such calculations are conditional on their assumptions and effect size. They are not evidence that the trial had a particular probability of finding an effect, and they are not observed power. The record does not report the trial's own sample-size justification, so the planning illustrations should not be mistaken for the original design rationale.

In general, a planning calculation is sensitive to the assumed effect: planning for a smaller effect requires more information than planning for a larger effect, all else equal. This is a general statistical principle, not a reported finding about this trial. Since the registry record does not report the primary outcome effect, it does not support interpreting the planning values as a forecast of the trial's actual result.

Binary outcomes and analysis choices

For a binary endpoint, the outcome count depends on both the definition and the population included. Here, the definition requires both clinical signs to be absent, and the registry specifies an analysis population limited to subjects with non-missing Clinical Resolution data, using last observation carried forward. In general, a missing-data rule can affect which recorded or imputed values contribute to an estimate. The record does not report how many values were missing, when they were missing, or the sensitivity of results to alternative assumptions.

The registry indicates that the primary outcome has several categories or time points and is not reduced to one comparison. In general, selecting among multiple outcomes, categories, or assessment times can raise multiplicity concerns: the chance of at least one apparently notable result can increase when many statistical tests are conducted. Methods such as prespecifying a primary comparison or adjusting for multiple testing can address this concern, but the statistical plan and any multiplicity procedure are not reported in the registry record. No specific procedure should be assumed.

Clinical Resolution is assessed at Visit 2 (Day 4 or 5), while the treatment regimen lasts 3 days. In general, the timing and rules for an endpoint assessment are part of its interpretation because they determine which observations count as outcomes. The record supplies the scheduled visit window and outcome definition, but does not report further assessment procedures or adjudication methods.

Reading the safety counts

The safety summaries report zero serious adverse events among 64 participants at risk in the besifloxacin group and zero among 72 at risk in the vehicle group. They also report other adverse events in 2 and 3 participants, respectively. Counts describe what was recorded in the listed groups; they do not establish that an event cannot occur or provide a complete comparison of all potential harms. The registry does not report event-level details for the other adverse events in these summaries.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies Clinical Resolution as the primary outcome, but also states that the primary outcome has several categories or time points and is not reduced to one comparison. No single primary contrast, testing hierarchy, or adjustment for multiple comparisons is reported in the registry record. In general, multiplicity matters when several outcomes or assessment times are tested because interpreting the most favorable result without accounting for the set of tests can overstate the evidence. The record does not say whether or how this issue was handled.

The stated Clinical Resolution analysis population includes only subjects with non-missing data, using LOCF (Last Observation Carried Forward). LOCF is a method that carries a participant's last observed value forward to a later assessment when a later value is missing. In general, this approach relies on assumptions about what the missing observation would have been. The record does not report the amount or pattern of missing data, the timing of carried-forward values, or sensitivity analyses using other methods. The impact of missingness on the reported results cannot be assessed because the efficacy results are not reported.

The registry does not report the full statistical analysis plan, the sample-size justification, or interim analyses. It also does not provide a detailed account of analysis populations for the listed secondary outcomes. These absences limit assessment of how outcomes, missing observations, and multiple analyses were handled. No particular protocol decision or analysis procedure should be inferred from the trial's status or the endpoint listing.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 2% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports no serious adverse events among the 64 participants at risk in the besifloxacin group and none among the 72 participants at risk in the vehicle group. It lists other adverse events in 2 besifloxacin participants and 3 vehicle participants. These are counts within the reported safety groups, not a complete account of every possible adverse event or a formal comparison of risk.

The record does not report deaths in these groups as a numerical count; the death fields are null. It also does not list serious adverse-event terms, and event-level descriptions for the other adverse events are not reported in the registry record. The figures therefore provide limited descriptive safety information. In general, zero recorded serious events does not prove that no such event can occur, and small event counts may be imprecise. No treatment conclusion should be drawn from these counts alone.

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

The registry record establishes that a randomized, double-masked, parallel Phase 3 trial compared besifloxacin ophthalmic suspension 0.6% with vehicle for bacterial conjunctivitis. It describes a 3-day, twice-daily regimen and defines clinical resolution as absence of both conjunctival discharge and bulbar conjunctival injection at Visit 2 (Day 4 or 5). These details clarify the question the trial was designed to address.

The record does not report the clinical-resolution results or a treatment-effect estimate. It also does not report results for microbial eradication, which is listed as a secondary outcome. Consequently, the posted information does not establish how the groups compared on efficacy, how precise an estimate might be, or whether an observed difference would be statistically compatible with a null hypothesis. Those questions require outcome data and an analysis that are not reported in the registry record.

The safety record lists no serious adverse events in either group and reports other adverse events in both groups. These counts are descriptive and do not, by themselves, establish the overall safety profile or a comparative effect. The registry does not provide event details for the other adverse events.

The trial status is terminated, but the reason is not reported in the registry record. The status should not be interpreted as evidence about efficacy, safety, or the completeness of analyses. In general, registry entries are useful for understanding the design and recorded outcomes, but absent results limit the conclusions that can be drawn. Planning illustrations, if consulted, describe hypothetical sample-size requirements under assumptions; they are not observed outcomes or evidence that the trial achieved a given power.

13. Why This Trial Matters Statistically

This trial illustrates why design details and outcome results need to be distinguished. The registry describes randomization, double masking, parallel groups, the treatment regimens, and a concrete clinical endpoint. Those details help define the intended comparison. Yet without reported endpoint counts or an analysis, the clinical question remains unanswered in the registry record. A clear design description does not substitute for an estimate of the treatment contrast.

The endpoint definition also shows how a composite clinical criterion operates at the participant level: both conjunctival discharge and bulbar conjunctival injection must be absent for a participant to qualify as resolved. In general, such definitions make the target outcome explicit, while also making clear that different choices of signs, thresholds, or assessment times could yield different measures. The record gives the assessment visit but does not provide results across the listed categories or time points.

The entry is also a useful reminder that missing-data and multiplicity information affect interpretation. The record names an LOCF approach for non-missing Clinical Resolution data, yet does not report the amount of missingness, sensitivity analyses, or a testing strategy for several categories or time points. Without those details and results, readers cannot assess the precision or robustness of an efficacy finding.

Finally, the safety counts are small descriptive summaries, not a complete comparative assessment. The terminated status does not explain why the trial ended. Taken together, the record supports a careful account of the trial's design and reporting limits, rather than a conclusion about treatment effect.

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 main limitation for statistical interpretation is that the registry record does not report efficacy results for Clinical Resolution or microbial eradication. It supplies no group outcome counts, effect estimate, confidence interval, or p-value for the clinical comparison. The primary outcome is also identified as having several categories or time points and is not reduced to one comparison, leaving the relevant contrast unclear in the posted record.

The record specifies an LOCF approach for the Clinical Resolution analysis population, but does not report the amount or pattern of missing data, the number of participants with non-missing outcome data, or sensitivity analyses. It does not report the detailed analysis plan, how any multiple comparisons were handled, or the sample-size justification. These omissions prevent an assessment of robustness and statistical precision.

The trial is marked terminated, and the reason for termination is not reported in the registry record. The record does not explain whether termination affected enrollment, follow-up, or completion of planned analyses. Although the adverse-event summaries include group counts, they do not provide serious-event terms or event-level descriptions for other adverse events. These limitations restrict interpretation to the design and limited descriptive safety information recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Clinical and Microbial Efficacy of Besifloxacin Ophthalmic Suspension, 0.6% in the Treatment of Bacterial Conjunctivitis — NCT01740388.
• Registry record last updated 2014-10-01; status last verified 2014-09.
• Results first posted 2014-09-17.
• 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.

18. Record Summary

NCT01740388 is a randomized, double-masked, parallel Phase 3 trial sponsored by Bausch & Lomb Incorporated. It enrolled 136 participants with bacterial conjunctivitis and compared besifloxacin ophthalmic suspension 0.6%, administered twice daily for 3 days, with vehicle administered on the same schedule.

The primary outcome is Clinical Resolution at Visit 2 (Day 4 or 5), defined as absence of both conjunctival discharge and bulbar conjunctival injection. Microbial eradication is listed as a secondary outcome. The record identifies an LOCF approach for non-missing Clinical Resolution data but does not report efficacy results or a single primary comparison. Safety summaries list no serious adverse events in either group and other adverse events in both groups. The trial status is terminated; the reason is not reported in the registry record.