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 A Safety and Efficacy Study of OZURDEX® in Macular Edema Associated With Branch Retinal Vein Occlusion (NCT01903720), a na phase 4 study. The primary outcome is Change From Baseline in Best Corrected Visual Acuity (BCVA) at Month 6.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01903720 |
| Phase | Phase 4 |
| Condition | Macular Edema, Retinal Vein Occlusion |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 71 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Allergan |
| Results posted | Yes |
2. Clinical Question
Population
Participants had macular edema associated with branch retinal vein occlusion. The study enrolled 71 participants, and its stated intent-to-treat population included all enrolled participants. For the primary outcome, the registry notes that the number available for analysis may be limited to those with data.
Intervention
Participants received OZURDEX®, a 700 µg dexamethasone implant. It was administered intravitreally on day 0 and approximately every 4 months as needed, based on physician judgment, for up to 12 months.
Comparator
The record describes a single-group study and does not report a control group. Allocation is listed as NA, and masking is listed as NONE. The study therefore does not provide a randomized, like-for-like treatment comparison.
Primary question
The primary outcome was change from baseline in best corrected visual acuity (BCVA) at Month 6, measured in letters read correctly on an eye chart. The registry record does not report the observed change or its uncertainty, so the result of that question cannot be assessed from the posted results.
3. Trial Design
This was a Phase 4, completed, single-group study sponsored by Allergan. The registry lists enrollment of 71 participants, with a study start date of 2013-07-16 and primary completion date of 2014-09-24. The condition of interest was macular edema associated with branch retinal vein occlusion.
The intervention was OZURDEX®, described as a 700 µg dexamethasone implant. The implant was administered intravitreally on day 0 and approximately every 4 months as needed, based on physician judgment, for up to 12 months. That as-needed schedule means treatment exposure was not described as a fixed repeat schedule for every participant. The record does not give the actual number of injections received by each participant.
The study model is single group, allocation is NA, and masking is NONE. No control group or randomized comparison is described. Consequently, the study can describe outcomes and adverse-event figures among participants treated in the study, but it cannot directly estimate a treatment contrast against a concurrent control group. Changes from baseline also cannot, by themselves, separate treatment-associated change from other influences on outcomes over time.
The primary outcome was change from baseline in BCVA at Month 6. The record also lists secondary outcomes addressing central retinal thickness, BCVA at other visits, change in BCVA of 15 or more letters, and receipt of additional injections. There are 12 outcome measures recorded, but the registry lists no analyses. The record does not report a statistical analysis plan, a sample-size justification, or whether any interim analyses were planned or conducted.
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 | OZURDEX® |
|---|---|
| STARTED | 71 |
| COMPLETED | 59 |
| NOT COMPLETED | 12 |
Reasons for not completing this period:
| Reason | OZURDEX® |
|---|---|
| Inclusion / exclusion criteria not met | 6 |
| Adverse Event | 1 |
| Rescinding of informed consent | 2 |
| Lost to Follow-up | 2 |
| Treatment with alternative drug | 1 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-treat (ITT) population included all enrolled participants. "n" in the category is the number of participants with data available for analysis.
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 | OZURDEX® |
|---|---|---|
| Participants analysed | 71 | |
| Age, Continuous | years | 57.46 (SD 9.19) |
| Age, Customized: 30 to 39 years | participants | 1 |
| Age, Customized: 40 to 49 years | participants | 12 |
| Age, Customized: 50 to 59 years | participants | 29 |
| Age, Customized: 60 to 69 years | participants | 22 |
| Age, Customized: 70 years and over | participants | 7 |
| Sex: Female, Male: Female | Participants | 33 |
| Sex: Female, Male: Male | Participants | 38 |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Best Corrected Visual Acuity (BCVA) at Month 6, measured over Baseline, Month 6.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | letters |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in best corrected visual acuity (BCVA) at Month 6, measured in letters. BCVA is assessed in the study eye using an eye chart, with the number of letters read correctly ranging from 0 (worst) to 100 letters (best). The registry explains that a positive change means the participant read more letters correctly and a negative change means fewer letters were read correctly.
Change from baseline is used to describe how a measured outcome differs from its starting value during follow-up. In a single-group study, this can show the direction and size of the observed within-participant change, if results are reported. It does not establish how the same participants would have fared without the intervention, because no concurrent control group is described.
The endpoint is reported as a mean, with standard deviation as its stated measure of dispersion. A mean gives an average change across participants with available data; the standard deviation describes how spread out individual changes are around that average. Those summaries answer different questions: the mean describes the group’s central result, while the standard deviation describes variability among participants.
The registry record gives the endpoint definition but no observed mean change, standard deviation, confidence interval, or analysis result. Therefore, the direction, magnitude, and precision of the primary outcome cannot be determined from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a clinically interpretable primary measure: change in BCVA, in letters, from baseline to Month 6. It also explains the direction of the scale: positive change corresponds to more letters read correctly, while negative change corresponds to fewer. However, it does not report the primary outcome’s observed mean, standard deviation, confidence interval, or test result. There is therefore no posted estimate to interpret for the primary question.
The distinction between an endpoint definition and an endpoint result is important. Defining BCVA and specifying the assessment time tells readers what was intended to be measured. It does not tell readers what happened among participants. Without observed results, neither the size nor the direction of the average change is available, and the variability of participant changes cannot be described. The registry also lists no analyses, so there is no reported inferential result to evaluate.
Even if a within-group change were reported, this design would not provide a randomized comparison with an untreated or alternative-treatment group. In general, a before-and-after result can reflect the intervention, the natural course of the condition, measurement variation, other care, or changes in who remains available for assessment. A single-group result therefore describes the participants’ measured course but does not isolate a causal treatment effect.
The record identifies secondary outcomes involving central retinal thickness and BCVA at other times, a threshold change of 15 or more letters, and additional injections. These outcomes could add descriptive context if results and analyses were available. The record does not provide those results. Their presence in the outcome list should not be mistaken for evidence that a particular change occurred.
Precision also cannot be judged. In general, a confidence interval expresses the range of values compatible with an estimate under the statistical method used; a narrower interval indicates greater precision than a wider interval. No confidence interval is reported for the primary outcome. The standard deviation is named as the measure of dispersion, but its observed value is also not reported. Thus neither uncertainty around the mean nor the spread of individual outcomes is available for assessment.
The posted safety figures are separate from the efficacy outcome. The record reports serious and other adverse-event figures for the OZURDEX® group, and names cataract and ovarian cancer among the top serious terms. Those entries describe recorded safety information; they do not establish that the intervention caused an event. The record does not report event attribution or a comparison group against which to interpret these counts.
Overall, the available information supports a description of the study design, intended endpoint, dosing approach, and recorded safety figures. It does not support a conclusion about the observed BCVA result, its precision, or a causal treatment effect. Those are not reported in the registry record.
9. Statistical Methods Explained
The primary measure is continuous: it is a numeric change in BCVA letters. The registry specifies that the primary result is expressed as a mean and that the standard deviation is the dispersion measure. These summaries describe different features of the data. The mean describes the average change, while the standard deviation describes how much individual changes vary around that mean. Neither value is reported for the primary outcome in the registry record.
What does a mean change describe?
For a continuous outcome, a mean change summarizes the average difference between participants’ baseline measurements and their later measurements. It is useful when the research question concerns the average direction and magnitude of change in the study group. A mean does not imply that each participant had a change of that size; individual responses may differ. The standard deviation helps convey that variation, but it is not a measure of uncertainty in the estimated mean.
In this study, the endpoint description makes the direction of change explicit. A positive number of letters means more letters were read correctly, and a negative number means fewer. That directional interpretation is meaningful only when an observed estimate is available. The record defines the endpoint but does not post an estimate, so there is no result to characterize as an increase or decrease.
How does a confidence interval help?
In general, a confidence interval communicates the precision of an estimated effect by giving a range of values compatible with the data and the method used. It is not a guarantee that the true value lies in that particular range. A narrower interval generally indicates a more precise estimate than a wider interval. Interpretation should consider both the location of the estimate and the interval’s width, rather than relying only on whether an interval includes a particular reference value.
No confidence interval for the primary outcome is reported in the registry record. The posted information therefore does not show how precisely the mean change was estimated. A standard deviation alone, even if reported, would describe participant-level spread rather than directly providing the uncertainty around the mean. The registry record reports neither the primary standard deviation nor a confidence interval.
What can a single-group design establish?
A single-group study can describe observed outcomes among the participants who received the intervention. When baseline and follow-up measurements are available, it can also describe change over time. But without a concurrent control group, a within-group change is not the same as a controlled treatment contrast. General influences such as the condition’s natural course, measurement variability, changes in other care, or participant selection over follow-up may also contribute to observed change.
Here, the registry describes a single-group model, allocation as NA, and masking as NONE. No like-for-like control comparison is listed. The design description therefore limits what can be inferred causally, regardless of whether a within-group change might be observed. The record does not report a statistical analysis plan that would clarify how the investigators intended to address these issues.
Why does over-dispersion matter?
General statistical explanation: over-dispersion refers to data that vary more than a model assumes. If a model understates variability, standard errors can be too small and confidence intervals can be too narrow, making results appear more precise than they are. This concern is relevant to methods that model counts or other outcomes with a variance assumption. The registry identifies a continuous primary outcome summarized by a mean and standard deviation, but does not report an analysis model, a dispersion assessment, or any evidence of over-dispersion. It would not be appropriate to claim that over-dispersion was present or addressed in this trial.
How should planning illustrations be read?
General statistical explanation: sample-size calculations depend on assumptions about the effect to detect, outcome variability, significance level, allocation, and analysis method. A planning calculation explores what a future study might require under those assumptions; it is not a result observed in the current study and is not observed power. The planning description associated with this study uses a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a stated fraction of the observed effect. These are planning assumptions, not a description of the single-group study’s actual design.
The planning description also distinguishes participant-per-arm calculations from total-event calculations for time-to-event settings. The primary endpoint is a continuous measure, and no time-to-event primary endpoint is specified. No sample-size justification for the trial itself is reported in the registry record. Because the primary observed effect is not reported, the planning assumptions should not be treated as evidence about the trial’s results or as confirmation that the study had adequate precision.
What does the registry report about analyses?
The registry lists 12 outcome measures and no analyses. That means the record identifies outcomes but does not post statistical analysis results for them. Without an analysis result, readers cannot assess an estimated effect, its uncertainty, a hypothesis test, or how the analysis handled incomplete observations. Statistical methods that may be familiar from other trials should not be attributed to this study unless they are documented in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 12 outcome measures, including the primary BCVA change at Month 6 and secondary measures involving BCVA, central retinal thickness, a threshold change in BCVA, and additional injections. Considering multiple outcomes can raise a multiplicity issue: in general, the more statistical comparisons made, the greater the chance of a chance-positive finding if results are interpreted without an appropriate strategy. A prespecified hierarchy, adjustment, or clearly defined focus can help address that concern. The registry record does not report a multiplicity strategy, so it is not possible to tell whether or how the investigators planned to account for multiple outcomes or assessment times.
The record lists no analyses. It therefore does not report which outcomes were analyzed, the statistical methods used, whether comparisons were adjusted, or whether analyses were prespecified. The existence of an outcome listing alone does not establish that results were analyzed or that any particular finding was statistically significant.
For the primary outcome, the intent-to-treat population is described as including all enrolled participants. The record also clarifies that the number in the outcome category is the number with data available for analysis. These statements distinguish the population definition from the availability of measurements: an intended analysis population can include all enrolled participants while the outcome data available for a particular analysis may be incomplete.
The registry record does not report the number with primary outcome data, reasons for missing measurements, or methods for handling missing data. It also does not describe imputation, sensitivity analyses, or assumptions about why data may be missing. Without this information and the outcome results, the effect of missingness on the primary estimate cannot be evaluated. These 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.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| OZURDEX® | 2 | 71 | 2.8% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| OZURDEX® | 44 of 71 |
Most frequent serious adverse event terms
| Event term | Organ system | OZURDEX® |
|---|---|---|
| Cataract | Eye disorders | 1 of 71 |
| Ovarian cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 71 |
Most frequent non-serious adverse event terms
| Event term | Organ system | OZURDEX® |
|---|---|---|
| Intraocular pressure increased | Investigations | 25 of 71 |
| Dry eye | Eye disorders | 14 of 71 |
| Cataract | Eye disorders | 12 of 71 |
| Conjunctival haemorrhage | Eye disorders | 8 of 71 |
| Headache | Nervous system disorders | 5 of 71 |
| Vitreous detachment | Eye disorders | 4 of 71 |
Serious events with the highest arm-level rate: cataract (1.4%), ovarian cancer (1.4%).
The registry reports a serious adverse-event figure of 2 among 71 at risk in the OZURDEX® group. It reports an other adverse-event figure of 44 among 71 at risk. These are safety entries for the single study group, not comparisons between treatments. The record also lists cataract and ovarian cancer as top serious adverse-event terms, each at 1.4%.
These figures should be read as registry-recorded safety information rather than proof of causation. The posted record does not establish that an event was caused by the implant, and it does not report a comparator group that could help distinguish background events from treatment-associated events. The serious-event terms also do not, by themselves, describe timing, duration, severity beyond their serious classification, or clinical course.
Deaths are not reported in the registry record. The record does not provide further details about event attribution or the methods used to collect and classify adverse events. Accordingly, the figures can describe what the registry lists for the study group, but they do not support a comparative estimate of safety or a causal conclusion.
12. What the Result Does, and Does Not, Mean
The study record establishes that a completed Phase 4, single-group study evaluated OZURDEX® in participants with macular edema associated with branch retinal vein occlusion. It describes the implant schedule and identifies change in BCVA at Month 6 as the primary endpoint. It also lists secondary outcomes and safety information. These design and endpoint details explain what the study set out to observe.
The posted results do not report the primary outcome estimate, its standard deviation, a confidence interval, or an analysis result. As a result, the registry record does not show whether average BCVA changed, in which direction it changed, how large any change was, or how precisely it was estimated. The record likewise does not provide results for the listed secondary outcomes.
Even if a within-group change were available, the study design would not establish a randomized treatment effect relative to a control. Change over time in a single group may reflect several influences, and the absence of a concurrent comparison limits causal interpretation. The registry does not describe an analysis that could overcome the fundamental lack of a control group.
The safety entries can be read as reported event figures for the OZURDEX® group, along with named serious-event terms. They do not prove that the intervention caused those events, and there is no control group for comparative safety interpretation. Event attribution and additional safety-analysis details are not reported in the registry record.
In short, the registry record supports conclusions about the study’s design, planned measurements, and recorded safety entries, but not about the primary efficacy result or a causal benefit-risk comparison. Missing outcome analyses and unreported methods leave key questions about effect size, precision, and handling of incomplete data unanswered.
13. Why This Trial Matters Statistically
This study is statistically notable because its design and outcome definitions are visible, while its outcome analyses are not reported in the registry record. Readers can identify the intended primary measure, the population definition, and the single-group treatment schedule. They cannot examine an estimated primary change or its uncertainty. That distinction is important: a well-defined endpoint does not substitute for a posted result.
The BCVA endpoint is expressed in letters and has an interpretable direction, making the outcome definition accessible. Reporting a mean together with a measure of dispersion would describe average change and participant variability; reporting an interval would also help readers judge the precision of the estimate. The record names the standard deviation as the dispersion measure but posts none of these primary results.
The single-group design also illustrates the difference between describing change and estimating a comparative effect. A baseline-to-follow-up change can be informative about the study participants’ observed course, but it cannot by itself show what would have happened under another treatment or without the intervention. That distinction matters when readers assess causal claims.
Finally, the registry lists a range of secondary measures and safety information, but no analyses. The outcome list signals the breadth of questions the study intended to assess; it does not reveal the findings or how multiplicity, missing data, or analysis choices were handled. The record therefore demonstrates why transparent reporting of estimates, uncertainty, and methods is necessary for meaningful statistical interpretation.
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 central limitation for interpreting the study is that the registry record does not report results for the primary endpoint or the listed secondary outcomes. The primary endpoint is defined, but its mean change, standard deviation, confidence interval, and analysis result are absent. The record lists no analyses, leaving no posted estimate to assess for direction, size, or precision.
The study is described as single group, with allocation listed as NA and masking as NONE. No randomized comparator is reported. Consequently, the design cannot provide a direct treatment contrast, and any within-group change, if results were available, would not isolate the intervention’s effect from other changes over time.
The registry notes that the intent-to-treat population included all enrolled participants, while the number contributing to an outcome analysis is the number with data available. It does not report the number with primary endpoint data, reasons for unavailable measurements, or methods for handling missing data. This prevents assessment of how incomplete follow-up might affect results.
The record lists multiple outcomes but does not report a multiplicity strategy or analysis plan. It does not state whether interim analyses were planned or conducted, nor does it report a sample-size justification for the trial. The planning assumptions described for sample-size illustrations should not be mistaken for the trial’s own design rationale.
For safety, the registry lists adverse-event figures and top serious-event terms but does not report event attribution or a comparative safety analysis. These limitations are specific to what the record documents; further details are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Safety and Efficacy Study of OZURDEX® in Macular Edema Associated With Branch Retinal Vein Occlusion — NCT01903720.
- Registry record last updated 2019-04-17; status last verified 2019-04.
- Results first posted 2016-07-21.
- 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.
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18. Record Summary
NCT01903720 is a completed Phase 4, single-group study sponsored by Allergan, with enrollment of 71 participants. It evaluated OZURDEX®, a 700 µg dexamethasone implant, in participants with macular edema associated with branch retinal vein occlusion. The implant was administered intravitreally on day 0 and approximately every 4 months as needed, based on physician judgment, for up to 12 months.
The primary endpoint was change from baseline in BCVA at Month 6, reported in letters. Secondary outcomes included further BCVA and central retinal thickness measures, a BCVA change threshold, and additional injections. The registry record lists no analyses and does not report the primary or secondary outcome results.
The record reports serious and other adverse-event figures for the OZURDEX® group and identifies cataract and ovarian cancer among the top serious terms. It does not report deaths, event attribution, a control group, or a statistical analysis plan. Thus, the record describes the trial’s design and intended measurements but does not permit assessment of the primary result or a comparative treatment effect.