Efficacy of AC-150 for the Treatment of Allergic Conjunctivitis in the Enviro-CAC™ Model: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy of AC-150 for the Treatment of Allergic Conjunctivitis in the Enviro-CAC™ Model (NCT01134328), a randomized phase 2 study. The primary outcome is Ocular Itching at Onset of Action (15 Minutes Post-dose).

2. Clinical Question

The study is described as a modified conjunctival allergen challenge (CAC) model conducted during pollen season. The brief summary frames the objective as evaluating AC-150 against vehicle and its components in the prevention of signs and symptoms of allergic conjunctivitis. That objective is not itself evidence of an effect: an assessment requires outcome results and a statistical comparison.

The primary endpoint focuses on itching after challenge rather than a general measure of symptoms across everyday settings. The endpoint description says patients assessed itching on a 0-4 scale, with higher categories representing more severe itching. Scores averaged over both eyes were analyzed. The recorded outcome timeframe is 3, 5, 7 minutes post-CAC, following a treatment efficacy CAC performed 15 minutes after instillation.

Although the record lists 23 outcome measures, it reports zero analyses. The registry record therefore does not provide the results needed to establish the direction, size, or precision of any comparison, whether for the primary endpoint or other outcomes. No conclusion about comparative efficacy can be drawn from the outcome definitions alone.

3. Trial Design

This was a Phase 2, randomized, double-masked, parallel study described as multi-center. Its official title identifies a comparison of cetirizine 0.1%/fluticasone 0.005% ophthalmic solution with its components and vehicle in a modified CAC model during pollen season. The registry record marks the study as completed and records enrollment of 83.

The four listed interventions were AC-150 Combo, AC-150A 0.1%, AC-150B 0.005%, and vehicle. Randomization means the study used an assignment process intended to allocate participants to treatment groups rather than relying solely on treatment choice. Double masking indicates that two parties were masked, but the registry record does not identify those parties or describe how masking was maintained. It also does not report the allocation sequence method or allocation concealment details.

A parallel design assigns participants to a study group and assesses outcomes within that group rather than having each participant receive every intervention in sequence. This design can support between-group comparisons, provided the analyses account appropriately for the randomized groups and the outcome data. The registry record does not describe the specific comparison model or adjustment variables.

The study start is recorded as 2010-05, with primary completion in 2010-07. The enrollment figure is a trial-level figure; the registry record does not give planned enrollment, recruitment flow, or primary-outcome analysis counts. Separate arm descriptions are blank. The safety records contain group-specific counts at risk, but those counts should not be treated as a complete account of the primary-outcome analysis population.

The registry record does not report the study protocol, the rationale for its design, sample-size justification, or the statistical analysis plan. It also does not report whether there were interim analyses or how the challenge procedures were standardized across centers. Those details cannot be inferred from the study title, design labels, or intervention list.

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.

Before assignment: There were 83 subjects enrolled, 12 subjects discontinued, and 71 subjects completed the study. Participant flow and baseline characteristics are presented for the 83 subjects that met all inclusion criteria and none of the exclusion criteria and were randomized to receive AC-150 Combo, AC-150A 0.1%, AC-150B 0.005% or Vehicle

Overall Study

Analysis population for the primary outcome, as defined in the registry: Intent to Treat (ITT)

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 Ocular Itching at Onset of Action (15 Minutes Post-dose), measured over 3, 5, 7 minutes post-CAC.

The primary endpoint is ocular itching at onset of action. It measures a patient-reported symptom on a 0-4 scale, from none to severe. The record says the treatment efficacy CAC took place 15 minutes after drop instillation, and that itching scores were assessed at 3, 5, 7 minutes post-CAC. The average score over both eyes was analyzed. The outcome is described as a mean, with standard deviation as the measure of dispersion, and its population is the Intent to Treat (ITT) population.

Itching is relevant to the study question because the brief summary concerns prevention of allergic conjunctivitis signs and symptoms, and itching is one of those symptoms. A symptom scale can translate a participant’s reported experience into an outcome that can be compared across randomized groups. In general, a lower mean on a scale coded from none to severe indicates less reported symptom intensity in the measured setting. That interpretation describes the scale, not a finding from this study.

The endpoint is tied to a controlled allergen challenge and a specified assessment window. It therefore represents itching under those study conditions, not necessarily symptom experience in other circumstances. The registry record does not report the observed group means, standard deviations, number of participants contributing outcome data, or treatment-effect estimates. Without those results, neither the size nor the precision of a group difference can be assessed.

The description identifies an average over both eyes, but does not state how individual assessment times were combined into the endpoint. That detail, along with the handling of incomplete assessments, is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record gives design labels and an endpoint description, but little detail about the statistical analysis. The explanations below describe general statistical principles relevant to this type of study; they should not be read as claims about analyses that were actually conducted.

What does a mean summarize?

The primary outcome is described as a mean of a continuous measure: ocular itching scores averaged over both eyes. A mean provides a single summary of the center of observed scores. The registry record specifies standard deviation as the dispersion measure. In general, a standard deviation describes how spread out observations are around the mean; it is not the uncertainty of the mean itself and does not give a treatment comparison on its own.

The itching scale is bounded from 0-4, with 0 meaning none and 4 meaning severe. A mean on such a scale can take intermediate values even though the individual scale categories are discrete. Summarizing with a mean can be useful for comparing average symptom scores, but it can hide differences in the distribution of scores. For example, groups with the same mean could have different patterns of responses. No group distributions are reported in the registry record.

What would a treatment contrast mean?

In general, a treatment contrast compares an outcome summary between groups. For a mean outcome, that may be expressed as a difference between group means, with the direction depending on which group is subtracted from which. A contrast needs to be interpreted alongside its uncertainty and the analysis population. This registry record does not report any primary-outcome contrasts, confidence intervals, or p-values, so the effect’s magnitude and precision cannot be assessed.

A confidence interval is a statistical range that reflects uncertainty in an estimate under a specified model and assumptions. A narrow interval generally indicates greater precision than a wide interval, but precision is not the same as clinical importance. A p-value, when used, addresses compatibility between the observed data and a specified null hypothesis under the analysis assumptions; it is not a measure of effect size or the probability that a treatment works. Neither kind of inferential result is reported for the primary endpoint.

Why does the design matter?

Random allocation is intended to make treatment groups comparable, on average, with respect to factors that could influence outcomes. Masking can reduce the influence of expectations on care, assessment, or reporting. A parallel design supports comparisons between groups assessed under the study conditions. These are general features of trial design, not assurances that bias was absent. The registry record labels the study randomized and double-masked but does not describe sequence generation, concealment, masking procedures, or assessment safeguards.

In a challenge model, the outcome is measured after an allergen challenge under specified study conditions. The primary description says that the treatment efficacy CAC occurred 15 minutes after instillation and that itching was assessed at 3, 5, 7 minutes post-CAC. The registry record does not state how the several assessment times were combined in the primary analysis, whether repeated observations were modeled jointly, or whether one time point was selected for a particular contrast. That specification is important for understanding what an analysis estimates.

How should variation and repeated assessment be considered?

For a continuous outcome, variability can arise among participants and across assessment occasions. When observations are repeated within a participant, those observations may be correlated rather than independent. General statistical methods for repeated measurements account for this dependence; treating correlated observations as independent can make uncertainty estimates misleading. The registry record does not describe whether repeated-measures methods were used or how within-participant correlation was handled.

Bounded symptom scores can also have non-normal distributions, especially when many observations fall at the scale boundaries. General analysis choices may include models for means or methods that respect the scale’s distribution. The registry record does not identify the model, diagnostic checks, transformations, or any robustness analyses. It is therefore not possible to assess whether the analysis assumptions were appropriate.

What is missing from the statistical plan?

The record does not report a sample-size justification, target effect, power calculation, significance threshold, confidence-interval approach, or prespecified analysis model. It also does not report covariate adjustment, handling of center effects, baseline adjustment, or the approach to any protocol deviations. These details are not recoverable from the phase, enrollment, or design labels. No analysis should be attributed to the investigators without a reported methods description.

Multiple treatment comparisons and outcomes can complicate interpretation. In general, when several hypotheses are tested, the chance of at least one apparently unusual result can increase if no multiplicity strategy is used. A prespecified testing order or adjustment can address some multiplicity concerns, but the registry record does not state whether either was used. Since the record lists multiple groups and outcome measures, the missing analysis plan limits interpretation of how any results would have been selected or evaluated.

The record’s sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are not evidence of the trial’s original design rationale or of observed power. The registry record does not report the original sample-size justification. More fundamentally, the primary outcome estimates needed to interpret any such illustration are not reported as analyzed results.

In summary, general statistical concepts clarify what an analysis could estimate, but they cannot replace the missing study analysis. The posted record permits readers to identify the outcome scale and stated summary approach; it does not permit verification of the model, estimation of a treatment contrast, or appraisal of inferential precision.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 23 outcome measures, including the primary itching outcome and secondary redness outcomes at different assessment times. It also indicates that the primary outcome has several categories or time points and was not reduced to one comparison. No analyses are reported. The record therefore does not establish which comparisons, if any, were conducted or how they were prioritized.

Multiplicity is a general statistical issue that arises when several outcomes, time points, treatment comparisons, or hypotheses are considered. If many tests are performed, some results may appear notable by chance. Researchers may address this through a prespecified primary comparison, a testing hierarchy, or an adjustment to inference. The registry record does not report whether any such approach was planned or used. Without the analysis plan and results, it is not possible to assess the consequences of multiple testing or to distinguish confirmatory from exploratory findings.

The primary population is identified as Intent to Treat (ITT). In general, an ITT approach analyzes participants according to their randomized group, regardless of treatment adherence, supporting the benefits of randomization. The registry record does not define the analysis population further, report the number analyzed, or explain how missing outcome measurements and protocol deviations were handled. It does not report whether all randomized participants contributed data to the primary analysis.

Missing-data methods can affect estimates when outcomes are not observed for everyone. General options depend on why data are missing and on the analysis model; no single method can be inferred from an ITT label. The record does not report missingness by group, imputation, sensitivity analyses, or the reasons for unavailable assessments. As a result, the extent to which missing outcome data might affect interpretation is unknown.

The registry record also does not report whether the analysis plan was finalized before results were examined. These omissions do not prove that the study lacked a plan or that data were missing. They mean only that those details are not reported in the registry record.

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 0% reporting threshold.

The adverse-event record lists zero serious adverse events in each of the four groups. It also lists zero other adverse events in each group. The corresponding numbers recorded at risk are 21 for AC-150 Combo, 21 for AC-150A 0.1%, 20 for AC-150B 0.005%, and 21 for vehicle. These figures describe what was entered in the registry record; they do not establish that no adverse events occurred outside the recorded definitions or observation period.

Zero recorded events is not the same as proof of zero risk. In general, an absence of observed events in a study leaves uncertainty about events that could occur but were not observed, particularly when the amount and duration of follow-up are limited. The registry record does not report the observation duration, adverse-event definitions, methods of elicitation, severity grading, or whether events were judged treatment-related.

The record does not list serious adverse-event terms. Death counts are not reported in the registry record. The adverse-event entries should be read separately from the missing primary efficacy analysis: they provide recorded safety counts but do not answer whether ocular itching differed across groups. They also do not provide a comprehensive safety profile.

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

The record establishes that a randomized, double-masked, parallel study evaluated AC-150 Combo, its two listed components, and vehicle in a modified conjunctival allergen challenge model during pollen season. It identifies ocular itching at onset of action as the primary outcome and describes how that outcome was assessed. It also records adverse-event counts by group.

Those details describe the question and the study structure, but they do not reveal the result. The registry record reports no analyses and provides no primary-outcome group means, treatment contrasts, confidence intervals, or p-values. Therefore, it does not show whether the combination, either component, or vehicle had higher or lower itching scores, nor whether any observed difference was precise or uncertain.

Missing results should not be interpreted as a null finding. A lack of reported analysis is not evidence that the groups were equal, that treatment had no effect, or that a difference was statistically significant. The study’s stated purpose and completion status likewise do not establish efficacy. Any conclusion about the comparative effects would require results and methods that are not reported in the registry record.

Even with results, interpretation would be specific to the measured endpoint and setting. The primary measure concerns patient-assessed itching following a treatment efficacy CAC in the Enviro-CAC™ model. It does not directly describe every symptom, all assessment times, or experience outside the study conditions. The record lists secondary redness outcomes, but does not report their results either.

The safety entries show zero recorded serious and other adverse events in each listed group, with group-specific at-risk counts. This is a limited registry summary, not proof that an intervention has no safety risks. Definitions, follow-up details, and a fuller adverse-event account are not reported.

The statistically responsible conclusion is narrow: the registry record describes a trial designed to compare the combination with its components and vehicle, but does not report the outcome analyses necessary to judge the comparisons. The results therefore remain indeterminate from this record.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it separates a combination intervention from its individual components and vehicle. In general, such a design can address more than whether a combination differs from a control: it can also examine whether its observed outcome differs from outcomes under the individual components. That makes the choice and reporting of contrasts important. The registry record identifies the four groups but does not report the comparisons or results.

The primary endpoint also illustrates the need to define a measurement precisely. Ocular itching was patient-assessed on a bounded 0-4 scale, averaged over both eyes, following a controlled allergen challenge. The record gives a timeframe involving 3, 5, 7 minutes post-CAC and describes the challenge as occurring 15 minutes after instillation. Reporting how those assessments contribute to one primary analysis would help readers understand the exact estimand—the treatment effect the analysis is intended to estimate. That detail is not reported.

Multiple outcomes and time points create another statistical consideration. The registry lists 23 outcome measures, while no analyses are reported. When a study considers many possible comparisons, an analysis plan is needed to clarify which findings are primary and how uncertainty is interpreted. The record does not report a multiplicity strategy, so readers cannot evaluate that aspect of the design or analysis.

The study also shows why registry design information and results serve different purposes. Randomization, masking, and a parallel structure describe intended safeguards and allocation features. They do not provide effect estimates. A completed study with an identified endpoint can still be statistically uninterpretable for efficacy when results, uncertainty, analysis methods, and missing-data handling are absent from the record.

For clinical researchers and biostatisticians, the key lesson is that endpoint definitions and design labels are not substitutes for transparent results reporting. Estimates, uncertainty intervals, analysis populations, and a clear account of planned comparisons are needed to assess the evidential strength and scope of a trial’s findings.

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 most consequential limitation of the registry record is the absence of outcome analyses. Although the study lists 23 outcome measures, it reports zero analyses and does not give primary-outcome results. There are no group summaries or comparative estimates to assess. This prevents evaluation of the magnitude, direction, and precision of the treatment comparisons.

The endpoint description leaves analytical details unresolved. It specifies patient-assessed itching, an average over both eyes, a 0-4 scale, and assessments at 3, 5, 7 minutes post-CAC. It does not state how these times were combined, which specific contrast was primary, or how any repeated assessments were modeled. The record also does not report the analysis model, assumptions, or sensitivity analyses.

Although the primary population is labeled ITT, the record does not report how that population was defined in practice, the number contributing primary-outcome data, or the handling of missing observations and protocol deviations. The arm descriptions are blank, and the registry record does not provide a detailed account of randomization, masking implementation, or allocation concealment. Enrollment is recorded as 83, but recruitment flow and outcome-specific analysis counts are not reported.

The study is described as multi-center and conducted during pollen season in a modified CAC model. The record does not report center-specific methods, participant characteristics, challenge standardization, or details that would help readers judge how findings might generalize beyond the study setting. It also does not provide the original sample-size justification, a statistical analysis plan, or an account of interim analyses.

The adverse-event summary is limited: the record contains zero serious and zero other adverse events in each listed group, but does not report definitions, collection methods, follow-up duration, or death counts. These omissions limit interpretation of safety as well as efficacy. They identify gaps in registry reporting and should not be treated as proof that the study itself did not collect the information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Efficacy of AC-150 for the Treatment of Allergic Conjunctivitis in the Enviro-CAC™ Model — NCT01134328.
• Registry record last updated 2017-09-14; status last verified 2017-09.
• Results first posted 2017-09-14.
• 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

NCT01134328 is a completed Phase 2 randomized, double-masked, parallel study of AC-150 for allergic conjunctivitis in the Enviro-CAC™ model. The official title describes a multi-center comparison of cetirizine 0.1%/fluticasone 0.005% ophthalmic solution with its components and vehicle during pollen season. Enrollment is recorded as 83; the study start is 2010-05 and primary completion is 2010-07.

The primary outcome was ocular itching at onset of action, assessed on a 0-4 scale after a treatment efficacy CAC. The primary population is identified as ITT. The record lists 23 outcome measures but reports zero analyses, so it does not provide primary-outcome estimates or comparative results. The adverse-event entries report zero serious and zero other adverse events for each listed group; death counts are not reported in the registry record.

The record supports a description of the study design and outcome definitions, but not a statistical conclusion about comparative efficacy. Important analysis details, including missing-data handling and multiplicity methods, are not reported in the registry record.