Safety and Efficacy of Ranibizumab for Diabetic Macular Edema: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy of Ranibizumab for Diabetic Macular Edema (NCT01982435), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Non-severe Ocular Adverse Events.

2. Clinical Question

The comparison concerns two dosing strategies for the same named drug, rather than ranibizumab versus a different treatment or no treatment. The trial title specifies that participants had previously received intravitreal bevacizumab. The brief summary identifies assessment of ocular and systemic adverse events as the primary objective. The registered primary outcome is narrower: the number of participants with non-severe ocular adverse events. Its description says events were identified through eye examination, including visual acuity testing, physical examination, participant reporting, and changes in vital signs.

The registry also lists visual acuity, central foveal thickness, anatomical dryness, visual gains and losses, visual acuity at 20/40 or better, angiographic leakage, and nonperfusion among secondary outcomes. These outcomes indicate that the record covers both safety and ocular measures, but the registry record does not supply a single primary-outcome comparison that can answer the main question quantitatively. The treatment schedule is described in detail for the monthly group. For the treat-and-extend group, the record says that after the loading doses, follow-up intervals were determined by the principal investigator based on OCT results; the remaining description is not reported in the registry record.

3. Trial Design

The registry identifies this as a randomized, parallel-arm trial with no masking and lists phases 1 and 2. It records enrollment as 27 and status as completed. The recorded start date is 2014-06-24, and the primary completion date is 2016-05-26. The sponsor is listed as Justis Ehlers.

Both arms received intravitreal ranibizumab. Group I, the monthly group, was scheduled to receive multiple open-label injections of 0.3 mg every 28 days, with a permitted interval of plus or minus 7 days from the last treatment, for 12 months. Group II, the treat-and-extend group, was scheduled to receive 3 initial loading doses of 0.3 mg every 28 days, with the same permitted interval. Following the third loading dose, the investigator was to determine follow-up intervals based on OCT results. The full extension rule is not reported in the registry record.

Randomization means assignment to the study groups was intended to be determined by chance, but the method of sequence generation and any allocation-concealment procedure are not reported in the registry record. The trial was unmasked, so masking of participants, clinicians, or assessors is not described as part of the design. Specific details about how adherence, treatment changes, or withdrawal were handled are not reported in the registry record.

The registry's primary objective concerns ocular and systemic adverse events after previous bevacizumab treatment. Its primary outcome is the number of participants with non-severe ocular adverse events over 12 months. Secondary outcomes include mean changes in best-corrected visual acuity and central foveal thickness, anatomical dryness by SDOCT, visual gains or losses of at least 15 letters, participants with visual acuity at 20/40 or better, angiographic leakage, and nonperfusion. The total number of outcome measures is listed as 12. A detailed protocol, full statistical analysis plan, and sample-size justification are not reported 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: Patients who exited the study early were accounted by using a last observation carried forward approach.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Non-severe Ocular Adverse Events, measured over 12 months.

The registered primary endpoint is the number of participants with non-severe ocular adverse events during the 12-month timeframe. It is a participant-count outcome: the question is how many participants meet the outcome definition, rather than how large a change occurs on a continuous scale. The description says assessment could draw on eye examinations, including visual acuity testing, physical examinations, participant reports, and changes in vital signs. It also says adverse events are covered in more detail in the adverse-event results.

Safety endpoints are used to describe harms observed during a trial. Counting participants can give a direct account of how many people were recorded as experiencing an event, while the separate adverse-event listings can describe event types. A count alone does not communicate the timing, duration, recurrence, severity, or clinical consequences of every event. Nor does a count by itself establish that a treatment caused an event.

The registry describes the primary outcome population as including patients who exited early, accounted for using last observation carried forward. This note specifies an approach for early exits, but does not give further detail about how the endpoint categories were constructed or how other missing observations were handled. The record identifies the endpoint and timeframe but does not provide a single comparative result for it. It explicitly notes that the primary outcome has several categories or time points and was not reduced to one comparison. Consequently, the posted information does not support a one-number estimate of the difference between the dosing groups for this primary endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General statistical explanation: A randomized design aims to make assigned groups comparable, on average, with respect to factors that could affect outcomes. Randomization does not guarantee that every characteristic will be balanced in a small study. The registry identifies random allocation but does not report the sequence-generation method, concealment procedure, or baseline characteristics in the registry record for this analysis. The allocation process and balance between the groups therefore cannot be assessed from the registry record.

The parallel-arm structure means participants were assigned to one dosing schedule rather than crossing between schedules as part of the stated design. Both groups received ranibizumab, making the central comparison one of schedule. The lack of masking matters because participants and study staff knew the assigned group. In general, knowledge of assignment can affect reports, care decisions, or outcome assessment, particularly for outcomes that involve judgment or participant reporting. The record does not specify whether outcome assessors were separately masked.

What does a participant count represent?

The primary endpoint is a count of participants with non-severe ocular adverse events. In general, binary-outcome summaries classify each participant as having or not having the defined event during the stated observation period, then report the number in each category. Such summaries are straightforward to read, but interpretation depends on a clear event definition and consistent observation. A count of participants is not the same as a count of all event episodes: one participant may have more than one event. The registry identifies the outcome as a count of participants, but detailed event-coding rules are not reported in the registry record.

For any comparison of two groups, the raw counts need to be interpreted with their group sizes and with the observation process in mind. The adverse-event record lists at-risk counts of 15 and 12 for the two groups. The primary outcome, however, is not presented as a single two-group comparison. No risk difference, relative measure, standard error, or confidence interval for that primary comparison is reported in the registry record. None should be inferred from the separate adverse-event counts.

Why can a confidence interval be useful?

General statistical explanation: A confidence interval conveys uncertainty around an estimated quantity under the assumptions of the statistical method. A narrow interval indicates greater precision than a wide interval, but an interval does not itself establish clinical importance or causation. In a small study, estimates can be imprecise, especially when events are uncommon. The registry entries do not give a confidence interval for the primary outcome comparison, so its precision cannot be assessed through an interval estimate.

What does the planning illustration describe?

General statistical explanation: A sample-size illustration asks how many participants a hypothetical study might need to detect a chosen effect under stated assumptions. It is not a measure of the probability that the completed study detected an effect, and it does not replace the observed treatment comparison. The registry's planning assumptions specify a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. The target effect is described as a stated fraction of the observed effect. For time-to-event tables, the stated convention is a total number of events; for other tables, it is participants per arm.

Those assumptions describe a planning illustration, not the trial's documented design rationale. The actual sample-size justification and the effect used for protocol planning are not reported in the registry record. Any planning quantities should be treated as hypothetical illustrations rather than evidence that the study had adequate power or that a non-significant result, if one were reported, would show equivalence. No sample-size calculation is an observed outcome.

What statistical plan is documented?

The registry lists one analysis and 12 outcome measures, but detailed methods for analysis are not reported in the registry record. The record does not specify a statistical model, a test for the primary endpoint, adjustment variables, confidence-interval procedures, interim analyses, or a hierarchy for outcome testing. It also does not state whether analysis followed intention-to-treat, per-protocol, or another named population definition. These details cannot be inferred from the randomized design alone.

General statistical explanation: Statistical models make assumptions about how outcomes vary and how observations relate to each other. For count data, over-dispersion means variability exceeds what a selected model expects; accounting for it can affect uncertainty estimates. The registry entries do not describe an over-dispersion assessment or a count model, and no such method should be attributed to this trial. Similarly, multiple outcomes or repeated time points can raise questions about multiplicity, but the presence of several outcomes does not reveal what adjustment, if any, was planned. The multiplicity approach is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and identifies several secondary outcomes, including visual acuity, central foveal thickness, anatomical dryness, visual gains and losses, and angiographic findings. It lists one analysis. The primary outcome is not reduced to a single comparison because it has several categories or time points. The analysis hierarchy and any procedure for controlling multiplicity are not reported in the registry record. In general, testing multiple outcomes or time points can increase the chance of at least one apparently unusual result; adjustment or a prespecified hierarchy may be used to address that issue. The record does not establish whether such methods were used.

The primary outcome description says patients who exited early were accounted for using last observation carried forward. In general, this method fills a later missing value with an earlier observed value. Its validity depends on assumptions about how outcomes change after the last observation; those assumptions are not reported in the registry record. The description does not clarify the amount or pattern of missing data, whether the approach applied to every endpoint, or whether sensitivity analyses were conducted.

The analysis populations are not fully described. The primary outcome population note gives the early-exit approach, but does not identify a named intention-to-treat or per-protocol population. The record does not state how deviations from assigned schedules, withdrawal, or other missing observations were handled. These omissions limit assessment of how the analysis population relates to the randomized groups and how robust the results are to missing data. A detailed statistical analysis plan is not reported in the registry record.

11. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: vertigo (8.3%), hospitalization for total hysterectomy (8.3%), hospitalization for hyperkalemia (8.3%), worsening of chronic kidney disease (6.7%), possible cellulitis to right lower extremity (6.7%).

The adverse-event record lists the monthly group with 15 participants at risk, 6 affected participants in the serious category, 15 in the other adverse-event category, and 0 deaths. The treat-and-extend group has 12 participants at risk, 3 affected participants in the serious category, 12 in the other adverse-event category, and 0 deaths. These figures describe recorded participants within the listed categories. They do not supply a single comparative estimate for the registered primary endpoint, which is non-severe ocular adverse events.

The record names serious terms with percentages: VERTIGO, 8.3%; HOSPITALIZATION FOR TOTAL HYSTERECTOMY, 8.3%; HOSPITALIZATION FOR HYPERKALEMIA, 8.3%; Worsening of Chronic Kidney Disease, 6.7%; POSSIBLE CELLULITIS TO RIGHT LOWER EXTREMITY, 6.7%; and TRANSIENT ISCHEMIC ATTACK, 6.7%. The registry entries do not identify the group associated with each listed term or provide enough detail to link an event to treatment. These terms should not be interpreted as evidence of causation. Counts and percentages are descriptive, and the record does not provide a complete account of event timing, recurrence, or individual clinical circumstances.

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

The results support a limited descriptive reading of safety information from a randomized comparison of two ranibizumab dosing schedules. The registry lists serious adverse-event affected-participant counts of 6 in the monthly group and 3 in the treat-and-extend group, other adverse-event counts of 15 and 12, and no deaths in either group. The groups have different listed at-risk counts. These figures alone do not establish that one schedule caused more or fewer events, and they are not a substitute for a prespecified comparative analysis.

The registered primary endpoint is non-severe ocular adverse events over 12 months, but the registry notes that the outcome has several categories or time points and is not reduced to one comparison. As a result, the record does not provide a single primary-outcome estimate with which to quantify a difference between the schedules. The primary objective also refers to systemic adverse events, while the registered primary endpoint is specifically ocular. The adverse-event listings add descriptive information, but they do not resolve the missing comparative endpoint result.

The trial record also names visual and anatomical secondary outcomes. Without numerical results for those outcomes, their direction, magnitude, and precision cannot be assessed. The presence of those outcomes in the registry should not be mistaken for evidence that either dosing schedule produced a particular visual or anatomical result.

In general, a randomized trial can inform a comparison only to the extent that its outcome definitions, analyses, and uncertainty are reported. Here, the registry entries identify the design and some event counts, but do not provide a single primary comparison or detailed statistical plan. The record therefore does not establish equivalence, superiority, or a causal safety difference between the regimens. It describes what was registered and the adverse-event counts posted, with substantial limits on comparative interpretation.

13. Why This Trial Matters Statistically

This trial is statistically notable because its two randomized groups received the same drug on different schedules. That design frames the question as a comparison of dosing approaches rather than a comparison between ranibizumab and an unrelated treatment. The parallel-arm, unmasked structure and the listed enrollment of 27 are important context for reading any observed group counts.

The record also illustrates a distinction between naming a primary endpoint and reporting a usable primary comparison. The primary outcome is defined as participants with non-severe ocular adverse events over 12 months, yet the registry states that it has several categories or time points and is not reduced to one comparison. Without a common estimate and a measure of uncertainty, readers cannot quantify the primary contrast from the registry record. This is a reporting limitation, not evidence that no analysis was performed.

Safety data can be informative even when a definitive comparative estimate is unavailable. The event counts and named serious terms show the kinds of information recorded, while also illustrating why denominators, outcome definitions, timing, and attribution matter. Counts from a small enrolled study are descriptive and should not be treated as proof of causation or as a complete characterization of risk.

Finally, the registry lists multiple secondary outcomes but does not report detailed methods for multiplicity, missing data beyond the stated early-exit approach, or the statistical analysis plan. Those omissions matter because interpretation depends not only on which outcomes were selected but also on how they were analyzed and how uncertainty was handled. The record is useful for understanding the intended comparison and the reported safety counts, while leaving key questions about comparative precision unresolved.

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 does not report a single comparative result for the primary outcome. The outcome is described as having several categories or time points, and the record says it was not reduced to one comparison. This prevents a direct estimate of the primary endpoint contrast from the available the registry entries.

The listed enrollment is 27, and the adverse-event groups have 15 and 12 participants at risk. These figures provide context for the counts but do not establish how many participants completed follow-up or how observations were distributed over time. The record does not report a detailed accounting of withdrawals, missing observations, protocol deviations, or adherence to the assigned schedules. It describes last observation carried forward for patients who exited early for the primary outcome population, but does not report the assumptions or sensitivity analyses associated with that approach.

The trial was unmasked, and the record does not specify whether outcome assessors were masked. The registry identifies randomization but does not report the sequence-generation method or allocation concealment. It also does not report baseline characteristics in the registry record, which limits assessment of group comparability.

Detailed statistical methods, the sample-size justification, interim analyses, and multiplicity procedures are not reported in the registry record. The registry lists secondary outcomes but does not provide their numerical results in the registry record for this analysis. Serious adverse-event terms are listed with percentages, but group attribution and detailed event-level context are not given. These limitations restrict assessment of precision, causal attribution, and the breadth of the findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety and Efficacy of Ranibizumab for Diabetic Macular Edema — NCT01982435.
• Registry record last updated 2020-11-03; status last verified 2020-10.
• Results first posted 2017-08-01.
• 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

The registry record describes a completed, randomized, unmasked, parallel-arm phase 1 and phase 2 trial of ranibizumab for diabetic macular edema previously treated with intravitreal bevacizumab. Enrollment is listed as 27. One group received monthly ranibizumab; the other received loading doses followed by a treat-and-extend schedule determined using OCT results. The primary objective concerned ocular and systemic adverse events, and the primary outcome counted participants with non-severe ocular adverse events over 12 months.

The record lists serious and other adverse-event counts, including 0 deaths in each group. It does not reduce the primary outcome to a single comparison, and detailed statistical methods, a sample-size justification, and multiplicity procedures are not reported in the registry record. Numerical results for the listed secondary outcomes are not reported in the registry entries analyzed. The available information therefore supports a description of trial structure and selected safety counts, but not a precise comparative estimate of the primary outcome.