A Phase 3 Study Evaluating the Efficacy and Safety of OCS-01 Eyedrops Compared to Vehicle for the Treatment of Ocular Inflammation and Pain Following Cataract Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Phase 3 Study Evaluating the Efficacy and Safety of OCS-01 Eyedrops Compared to Vehicle for the Treatment of Ocular Inflammation and Pain Following Cataract Surgery (NCT05147233), a randomized phase 3 study. The primary outcome is Absence of Anterior Chamber Cells at Visit 6..

2. Clinical Question

3. Trial Design

This was a randomized, double-masked, vehicle-controlled, parallel-group Phase 3 study of OCS-01 after cataract surgery. The registry lists Oculis as the sponsor and reports enrollment of 241. The study start date was 2022-06-24, primary completion was 2023-06-22, and the record lists the study status as completed. The title describes evaluation of efficacy and safety for inflammation and pain following cataract surgery.

Participants were assigned to OCS-01 or vehicle. In the OCS-01 arm, the study eye received one drop of dexamethasone ophthalmic suspension 1.5% [15 mg/mL] once daily for 14 days, beginning 1-day post-surgery. The vehicle arm used one drop in the study eye on the same daily schedule and for the same duration. The posted primary outcome uses 119 study eyes in the OCS-01 group and 122 in the vehicle group.

Randomization means treatment assignment was not determined solely by participant or clinician choice. Double masking is intended to limit knowledge of assignment during the study, while vehicle control provides a comparator alongside the active regimen. The registry does not describe the randomization procedure, the specific people who were masked, or procedures for maintaining masking. It also does not report further details about sites, eligibility criteria, or treatment adherence in the record summarized for this outcome.

The primary endpoint was absence of anterior chamber cells at Visit 6 on Day 15, expressed as a percentage of study eyes. The record identifies the analysis population as FAS, without defining the abbreviation in the outcome entry. The results are an endpoint comparison at a specified visit; they do not describe the pattern of responses at other times. Although the record lists two outcome measures and two analyses, no secondary results are posted 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: FAS

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.

Population: The full analysis set (FAS) consists of all randomized subjects who were analyzed under the treatment to which they were randomized.

6. Primary Endpoint

The registry lists the primary outcome as Absence of Anterior Chamber Cells at Visit 6., measured over Day 15.

The primary endpoint is the percentage of study eyes with absence of anterior chamber cells at Visit 6, assessed on Day 15. Anterior chamber cells are an observed sign used to assess inflammation in the front part of the eye. In this trial, their absence at the specified visit is a binary outcome for each study eye: the eye either met the stated absence criterion or it did not. The registry expresses the arm results as percentages rather than as a continuous measurement.

Using a specified sign at a specified visit gives the comparison a concrete clinical focus: the proportion of eyes meeting the endpoint at the end of the stated treatment period. It also makes the arm percentages interpretable as proportions of study eyes, rather than as average changes in a scale. The primary outcome description names the visit and timing but does not state the grading criteria, assessor procedures, or how borderline assessments were classified. Those details are not reported in the registry record.

The endpoint is reported for the FAS population. The record does not define that population, so its membership and handling of participants without a Day 15 assessment cannot be inferred from the endpoint entry alone. The registry reports 57.2% for OCS-01 and 24.0% for vehicle. These figures describe the observed endpoint percentages in the posted analysis, not every aspect of inflammation, pain, recovery, or safety after surgery.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a count-based endpoint expressed as a percentage: whether an eye had absence of anterior chamber cells at Visit 6 on Day 15. For each arm, the registry reports the percentage and the number of study eyes. The reported comparison is a difference in percentages, with a confidence interval and a Wald test. These quantities answer related but distinct questions: the arm percentages describe the observed endpoint, the difference estimates the contrast between arms, the interval describes uncertainty around that contrast, and the test assesses compatibility with a null difference under its assumptions.

What a difference in percentages expresses

A difference in percentages is an absolute contrast between the endpoint percentages, not a relative change. The registry reports 57.2% for OCS-01 and 24.0% for vehicle, and reports the difference as 33.2. The comparison is therefore read in the endpoint’s own units: percentage points. The reported direction favors a higher percentage of eyes meeting the stated absence criterion in the OCS-01 arm. This is a description of the posted result, not a statement about every possible outcome of treatment.

How to read the confidence interval

The reported 95% confidence interval runs from 21.5 to 44.9. In general, a confidence interval is a range generated by a statistical procedure that reflects sampling uncertainty around an estimate. Under repeated use of the same procedure and its assumptions, intervals would capture the parameter at the stated rate. For an individual trial, the interval does not assign a probability to the parameter being inside these particular limits. It conveys precision: narrower intervals indicate less uncertainty about the estimated contrast than wider intervals, all else equal.

Because the reported interval lies on the positive side of zero, it is consistent with a positive difference under the Wald analysis. Its limits are also important: the point estimate should not be treated as exact, and values across the interval remain compatible with the reported analysis. The registry does not give additional interval estimates for other populations or endpoints.

What the Wald test contributes

The registry names a Wald test and reports p < 0.001. In general, a Wald test compares an estimate with a hypothesized value, taking account of its estimated uncertainty. Here, the relevant null comparison is no difference in percentages. A small p-value indicates that results at least as incompatible with that null would be unusual if the null and the test assumptions held. It does not measure the probability that the finding is due to chance, and it does not quantify the size or practical importance of the difference. The confidence interval and p-value are complementary summaries of the same inferential comparison.

Why the endpoint form matters

A binary endpoint reduces each eye’s status at the assessment to whether the stated criterion was met. This makes the result directly interpretable as a percentage, but it also means information about degree, duration, or change in cell findings is not contained in that percentage. The record does not state the detailed cell-grading scale or its classification rules. In general, the precision of a binary-outcome estimate depends on the amount of information available and on how often the endpoint occurs. The reported arm counts and percentages should be understood in that framework.

The registry identifies the primary analysis population as FAS, but does not define it. It also does not describe the analysis model beyond naming the Wald test for the difference in percentages. No details are reported about adjustment for baseline characteristics, stratification, covariate handling, or sensitivity analyses. Those methods should not be inferred from the test name alone.

Why the posted design assumptions cannot be reconstructed

General statistical planning asks how much information is needed to detect a chosen effect under specified assumptions. Planning illustrations based on an observed effect are not observed power and do not explain the trial’s original design. The registry record does not report the original sample-size justification, its assumed effect, or any interim analysis plan. It therefore cannot establish whether the completed enrollment matched a particular power target or how design decisions were made. A sample-size rationale should not be reverse-engineered from the observed result.

The registry also does not describe missing-data methods. In general, missing outcomes can affect a percentage comparison if the likelihood of assessment differs across arms or relates to endpoint status. Without a stated denominator policy, imputation method, or sensitivity analysis, it is not possible to determine from the outcome entry how missing Day 15 observations were handled. The inferential result should therefore be read as the analysis reported, with these aspects of its implementation not reported in the registry record.

10. Analyses Reported by the Sponsor

The registry reports a Wald test for the difference in percentages: 33.2, with a 95% confidence interval from 21.5 to 44.9 and p < 0.001. This is the inferential result available for the primary endpoint. No separate recalculated comparison is reported in the registry record, so there is no second estimate or test to set alongside the registry analysis.

The primary endpoint is a count expressed as a percentage, and the registry record notes that values are missing or not estimable for a two-arm comparison of this count-other endpoint. Accordingly, a separate unadjusted re-calculation is not available for comparison. The posted Wald analysis should be read as the registry’s reported analysis, rather than as a result independently reproduced from summary statistics. The record does not identify additional details about the calculation beyond naming the test and reporting its estimate, interval, and p-value.

No discrepancy is flagged between a reported analysis and a recalculation. That absence of a flag is not a substitute for independent participant-level verification, which is not reported in the registry record. Interpretation should therefore retain the distinction between the reported statistical result and any independent reproduction: only the former is available for this endpoint.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and two analyses, but no secondary results are posted. The primary endpoint is identified as absence of anterior chamber cells at Visit 6 on Day 15. The registry record does not explain how the primary endpoint was selected among outcomes, whether other comparisons were considered confirmatory, or how multiple testing was handled. No multiplicity adjustment or hierarchical testing strategy is reported. The reported p-value should consequently be read as the value attached to the stated primary comparison, not as evidence about any unposted outcome or an unspecified family of tests.

The record labels the primary analysis population FAS, but does not define the population or list its inclusion rules. The endpoint arm counts are 119 for OCS-01 and 122 for vehicle. The registry record does not clarify whether these counts represent all randomized participants, all participants with an observed assessment, or another analysis denominator. It also does not describe exclusions, protocol deviations, treatment discontinuation, or how these matters affected the analysis population.

Missing-data handling is not reported in the registry record. There is no description of imputation, a missing-at-random assumption, a complete-case approach, or sensitivity analyses. For an endpoint recorded at a particular visit, missing assessment status can affect both the denominator and the interpretation of the resulting percentage. Without a stated method, the reader cannot determine whether missingness was included in the analysis, how it was treated, or whether the conclusion was tested under alternative assumptions.

These omissions do not alter the fact that a specific Wald result is posted, but they limit assessment of its robustness and of the broader evidence across outcomes. The record also does not report interim analyses, stopping rules, or a full statistical analysis plan. Those details should not be inferred from the trial phase, outcome labels, or the reported p-value.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: covid-19 (0.8%).

The registry lists serious adverse events for 0 of 119 participants in the OCS-01 group and 1 of 122 in the vehicle group. It lists other adverse events for 2 of 119 and 8 of 122, respectively. Deaths are listed as 0 in each group. Covid-19 is listed among the top serious adverse event terms at 0.8%. These are descriptive counts from the posted safety record, not the primary endpoint comparison.

Adverse-event counts do not by themselves establish that an event was caused by a study treatment. They also do not show how long each participant was followed for safety, whether events occurred during treatment or later, or how events were assessed for relationship to study drug. Those details are not reported in the registry record. A zero count in one arm means no event of that category was listed for that arm in the posted figures; it does not establish that the risk is absent.

The counts are small, so differences in the observed totals should be interpreted cautiously. The record does not provide a formal comparative safety analysis, confidence intervals, or event-level descriptions beyond the listed serious-event term. The safety figures should be read as a limited account of events reported in the registry, separate from the Day 15 efficacy result.

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

The posted result describes one randomized comparison of OCS-01 with vehicle after cataract surgery. For the primary endpoint, absence of anterior chamber cells at Day 15 was reported for 57.2% of study eyes in the OCS-01 arm and 24.0% in the vehicle arm. The registry reports a difference in percentages of 33.2, a 95% confidence interval from 21.5 to 44.9, and p < 0.001 from a Wald test. These figures indicate a statistical difference on the stated endpoint in the analysis recorded.

That result does not describe every dimension of postoperative inflammation or pain. It does not establish how quickly the endpoint was reached, how long it persisted, or whether other symptoms or outcomes differed. The registry record does not post secondary results, so no broader outcome pattern can be assessed from the record. Nor does the endpoint alone establish an overall balance of benefits and risks; the safety figures are limited descriptive counts without a reported comparative analysis.

The result also does not resolve questions about the analysis population or missing assessments. FAS is named but not defined, and methods for missing data are not reported in the registry record. The endpoint description does not provide the grading rules or assessor details. These details matter for understanding exactly how eyes were classified and which observations contributed to the percentages.

Statistical significance is not the same as clinical importance. The p-value addresses compatibility with a null difference under the test assumptions; it does not determine whether the magnitude is meaningful to patients or clinicians. The confidence interval gives a range of estimates compatible with the analysis, while leaving uncertainty. The posted evidence should therefore be interpreted narrowly: it concerns the specified Day 15 endpoint and its reported analysis, not an unrestricted conclusion about all outcomes or future settings.

14. Why This Trial Matters Statistically

This trial illustrates why a clinical result should be read through its endpoint definition and not only through its p-value. The primary question is framed as a percentage of study eyes meeting a defined finding at a specified postoperative visit. That makes the result accessible, but it also sets a boundary on what the comparison can establish. The percentages concern absence of anterior chamber cells at Day 15, not a general measure of every aspect of recovery.

The reported difference, confidence interval, and Wald test each contribute a different piece of information. The point estimate gives the direction and magnitude of the posted contrast; the interval shows uncertainty around it; and the p-value assesses compatibility with a null difference under the named method. Reading these together is more informative than treating a thresholded p-value as a complete account of the result. Here, the reported interval lies above zero, while its range still makes clear that the estimate is not exact.

The trial also underscores the importance of transparent reporting. The registry identifies FAS as the analysis population and names the Wald test, but does not define the population, explain missing-data handling, or describe multiplicity procedures. Without those details, readers cannot fully assess sensitivity to analysis choices or the relationship between the primary result and unposted outcomes. That uncertainty is about what the registry record documents, not proof that the trial lacked such procedures.

Finally, the posted safety counts and the primary efficacy result answer different questions. Sparse descriptive event totals should not be treated as a substitute for a full safety analysis, just as a primary endpoint comparison should not stand in for unreported secondary outcomes. Keeping those distinctions clear helps prevent a narrow statistical finding from being generalized beyond the evidence recorded.

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 registry record gives a concise account of the primary comparison but leaves several trial-specific details unavailable. It does not define FAS, even though that is the named primary analysis population. The outcome entry also does not specify the grading criteria for anterior chamber cells, who assessed the endpoint, or how assessments were conducted. These omissions make it difficult to judge the operational details behind classification of an eye as having absence of cells.

The record reports arm counts and percentages but does not explain the handling of missing Day 15 observations, withdrawals, or protocol deviations. It does not state whether the listed counts are the complete analysis denominators or how those denominators were determined. This limits assessment of potential effects of missing outcome data on the posted estimates. No sensitivity analyses are reported in the record.

Multiplicity procedures are not reported, despite the listing of two outcome measures and two analyses. No secondary results are posted, so the primary result cannot be considered alongside a complete set of outcomes. The registry record also does not report the sample-size justification, interim analysis plan, or a detailed statistical analysis plan. These should be treated as unreported, rather than inferred from the trial’s phase or from its completed status.

The safety record provides counts but not a full event-level account or a formal between-arm safety analysis. It does not provide additional detail about event timing, duration, seriousness assessment, or relationship to treatment. Finally, a registry result is limited to what is entered in the record; the posted primary comparison cannot answer questions about longer-term outcomes, other endpoints, or the reproducibility of the analysis from participant-level data.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Phase 3 Study Evaluating the Efficacy and Safety of OCS-01 Eyedrops Compared to Vehicle for the Treatment of Ocular Inflammation and Pain Following Cataract Surgery — NCT05147233.
• Registry record last updated 2025-07-11; status last verified 2025-05.
• Results first posted 2025-07-11.
• 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 record describes NCT05147233, a completed randomized, double-masked, vehicle-controlled, parallel-group Phase 3 study sponsored by Oculis. It enrolled 241 participants and evaluated OCS-01 eyedrops against vehicle following cataract surgery. The study eye received one drop once daily for 14 days, beginning 1-day post-surgery.

The primary outcome was absence of anterior chamber cells at Visit 6 on Day 15, expressed as a percentage of study eyes in the FAS population. The registry reports 57.2% for OCS-01 and 24.0% for vehicle, with a difference in percentages of 33.2, a 95% confidence interval from 21.5 to 44.9, and p < 0.001 by a Wald test.

The record lists serious adverse events in 0 OCS-01 participants and 1 vehicle participant, and other adverse events in 2 and 8 participants, respectively. It does not post secondary results or report detailed methods for population definition, missing data, or multiplicity.