Multicenter 12 Months Clinical Study to Evaluate Efficacy and Safety of Ranibizumab Alone or in Combination With Laser Photocoagulation vs. Laser Photocoagulation Alone in Proliferative Diabetic Retinopathy (PRIDE): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Multicenter 12 Months Clinical Study to Evaluate Efficacy and Safety of Ranibizumab Alone or in Combination With Laser Photocoagulation vs. Laser Photocoagulation Alone in Proliferative Diabetic Retinopathy (PRIDE) (NCT01594281), a randomized phase 2 study. The primary outcome is Change From Baseline in Area of Neovascularizations (NVs) at End of Core Study (EOCS).

2. Clinical Question

This was a proof-of-concept comparison of three treatment strategies in PDR, not a comparison against no treatment. The endpoint focused on the area of abnormal new blood vessels in the study eye. The registry describes a higher positive change as potentially indicating more new vessel formation and disease progression. The primary measure was continuous, so group results were reported as means and standard deviations, with comparisons reported as mean differences or adjusted least-squares mean differences.

3. Trial Design

NCT01594281 was a Phase 2, randomized, parallel-group, open-label study sponsored by Novartis Pharmaceuticals. The registry lists enrollment as 107 and the study status as completed. The study start date was 2012-12-11, and the primary completion date was 2016-11-30. It was described as a multicenter, three-arm, 12-month clinical proof-of-concept study.

The three groups received ranibizumab alone, PRP alone, or ranibizumab plus PRP. Ranibizumab was given as a 0.5 mg intravitreal injection. In the ranibizumab-only group, injections were administered monthly until stability in morphological parameters was confirmed, defined in the arm description as no further improvement or worsening for 3 consecutive months. The combination group used ranibizumab and PRP until that stability criterion was confirmed. PRP was administered according to modified diabetic retinopathy study guidelines.

Masking was listed as none, so the study was open-label. The primary outcome was change from baseline in neovascularization area at EOCS. The primary analysis population was listed as FAS; LOCF, with patients included only if they had baseline and at least one post-baseline value. The primary outcome description notes that one study eye per patient contributed to analysis.

The registry also lists secondary outcomes covering month 3 neovascularization area, visual acuity, diabetic retinopathy severity, retinal thickness, ranibizumab injections, and PRP laser spots. The record includes safety periods through month 12 and from month 12 to 24. The original sample-size rationale, allocation ratio assumptions, and detailed operational procedures beyond the arm descriptions 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.

Before assignment: The number of patients in the protocol section (107) excludes one patient in the Ranibizumab mono arm who withdrew prior to the baseline visit. The number of patients in the Randomized Set (108) includes this patient. A separate Informed Consent was signed for the Non-Interventional Follow Up Phase

Interventional Core Phase

Reasons for not completing this period:

Non-Interventional Follow Up Phase

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: FAS; LOCF. Only patients with both values at baseline and any post-baseline value were included.

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: Safety Set

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in Area of Neovascularizations (NVs) at End of Core Study (EOCS), measured over Baseline, EOCS.

The primary endpoint was change from baseline in the area of neovascularizations (NVs) at the end of the core study. The area was assessed centrally from fluorescein angiography images and calculated by combining the area of neovascularization of the disc (NVD) with neovascularization elsewhere (NVE). The unit was square millimeters. One study eye contributed to the analysis.

This is a continuous measure: each participant's result reflects the measured area change, and group results are summarized by a mean and standard deviation. In the registry's description, a higher positive change may indicate greater formation of new, abnormal blood vessels and therefore disease progression. A negative mean change indicates a decrease from baseline in the measured area on average, but the group mean does not show how every participant changed.

The endpoint is relevant to the study question because it quantifies retinal neovascularization, a central feature of PDR, rather than relying only on treatment delivery or a broad clinical label. Measuring the endpoint at EOCS permits comparison of the three assigned treatment strategies over the core study period. The record also reports an assessment of the same NV-area outcome at Month 3 as a secondary outcome. The registry does not report a clinically important difference threshold for interpreting changes in square millimeters.

7. Results Posted in the Registry

• PRP Mono: mean -0.90 versus -4.60 on control; difference 3.70 (95% CI -0.38 to 7.78), standardized effect d = 0.44; z-test p = 0.075.
• Ranibizumab+PRP: mean -1.70 versus -4.60 on control; difference 2.90 (95% CI -1.09 to 6.89), standardized effect d = 0.35; z-test p = 0.154.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Change From Baseline in Area of Neovascularizations (NVs) at Month 3

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • PRP Mono: mean -0.70 versus -5.90 on control; difference 5.20 (95% CI 0.76 to 9.64), standardized effect d = 0.56; z-test p = 0.022.
  • Ranibizumab+PRP: mean -2.70 versus -5.90 on control; difference 3.20 (95% CI -1.33 to 7.73), standardized effect d = 0.34; z-test p = 0.166.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for PRP Mono than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Ranibizumab+PRP and the control. The interval gives the range of effects that remain compatible with the data.

Best Corrected Visual Acuity (BCVA) (ETDRS Letters) at EOCS

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • PRP Mono: mean 76.80 versus 84.40 on control; difference -7.60 (95% CI -13.91 to -1.29), standardized effect d = -0.56; z-test p = 0.018.
  • Ranibizumab+PRP: mean 78.90 versus 84.40 on control; difference -5.50 (95% CI -10.40 to -0.60), standardized effect d = -0.52; z-test p = 0.028.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for PRP Mono than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Ranibizumab+PRP than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Change From Baseline in Central Subfield Thickness at EOCS

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • PRP Mono: mean 36.20 versus -6.00 on control; difference 42.20 (95% CI 21.84 to 62.56), standardized effect d = 1.04; z-test p = <0.001.
  • Ranibizumab+PRP: mean 17.60 versus -6.00 on control; difference 23.60 (95% CI 6.35 to 40.85), standardized effect d = 0.68; z-test p = 0.007.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for PRP Mono than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Ranibizumab+PRP than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry names secondary outcomes spanning neovascularization area at Month 3, visual acuity, diabetic retinopathy severity, retinal thickness, injection counts, and laser spot counts. Detailed numerical summaries recorded in the secondary results cover Month 3 neovascularization area, best corrected visual acuity at EOCS, and central subfield thickness at EOCS. The record's list of outcomes is broader than the detailed secondary summaries available in the record.

Across these secondary measures, the comparisons do not form a single uniform pattern: some group contrasts have intervals that exclude zero, while others remain compatible with zero. The endpoint definitions also differ, with measurements of vessel area, visual acuity, and retinal thickness representing distinct aspects of the disease and its assessment. They are related to the primary question, but they do not substitute for the primary neovascularization-area outcome.

These findings should be considered exploratory in the absence of a reported multiplicity strategy. General explanation: when many outcomes and pairwise comparisons are examined, the chance of at least one apparently unusual result can increase even if there are no true differences. Adjustment methods, prespecified hierarchies, and clear designation of primary outcomes can help govern interpretation, but the registry record does not report such a procedure for these secondary results.

Accordingly, the secondary results can describe patterns that merit attention, but they carry less inferential weight than a single prespecified primary comparison, particularly when the adjustment approach and full analysis plan are not reported. They should not be treated as independent confirmations of the primary result or as definitive evidence about outcomes not designated as primary.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Change From Baseline in Area of Neovascularizations (NVs) at Month 3
• Best Corrected Visual Acuity (BCVA) (ETDRS Letters) at EOCS
• Percentage of Patients With Change From Baseline in BCVA (ETDRS Letters) at EOCS
• Number of Patients With Change From Baseline in ETDRS Severity Grade of Diabetic Retinopathy (DR) at EOCS
• Change From Baseline in Central Subfield Thickness at EOCS
• Change From Baseline in Foveal Center Point Retinal Thickness at EOCS
• Number of Ranibizumab Injections Until EOCS
• Number of PRP Laser Spots Until EOCS

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous, and its group summaries are means with standard deviations. This lets readers see both the average change in neovascularization area and the degree of variation among participant measurements. A mean describes the center of the observations, while a standard deviation describes their spread. Neither one alone conveys the full distribution or shows whether every participant changed in the same direction.

What does ANCOVA contribute?

The sponsor reported pairwise analyses using ANCOVA and expressed the results as least-squares mean differences. General explanation: analysis of covariance models an outcome while accounting for selected covariates. A least-squares mean is a model-based estimate, and its contrast may differ from a raw difference between the observed group means. The covariates and full model specification are not reported in the registry record, so the adjusted estimates cannot be reconstructed from the information recorded there.

The record also permits simple, unadjusted recalculations from the posted means, standard deviations, and group sizes. Those are descriptive comparisons based on summary statistics, not replacements for the sponsor's model. The recalculated primary mean differences are 3.7 for PRP alone versus ranibizumab alone and 2.9 for the combination versus ranibizumab alone. Their unadjusted p-values are 0.075 and 0.154. These calculations do not adjust for baseline values or other covariates. Since the registry flags a discrepancy between the recalculation and the sponsor analysis, the sponsor's own analysis takes precedence.

How should p-values be read?

General explanation: a p-value measures how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the model assumptions were true. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. The p-values in the registry are attached to particular contrasts and analysis methods. The record does not report whether these tests were adjusted for the several comparisons or outcomes.

The primary population is described as FAS; LOCF. LOCF means that a participant's last observed post-baseline value is carried forward to represent a later assessment when required by the analysis procedure. General explanation: this approach can simplify analysis of missing follow-up measurements, but it relies on assumptions about what the unobserved outcome would have been. The registry says that only participants with both baseline and any post-baseline values were included. Further details about missingness, reasons for missing data, or sensitivity analyses are not reported in the registry record.

What do the group sizes represent?

The primary outcome summaries list 33.0 in each arm. These are analysis counts for that outcome, not necessarily the number randomized or the number included in every other outcome analysis. Other outcomes have different analysis counts. General explanation: outcome-specific counts can vary when measurements are unavailable or eligibility for an analysis differs; the record does not give enough detail to attribute the variation to a particular reason.

For planning illustrations, the calculations use the observed effect or a stated fraction of it, a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. These illustrations describe how sample size changes with assumed effect size; they are separate from the trial's original design. The original sample-size assumptions and justification are not reported in the registry record.

General explanation: over-dispersion means that outcome variability is greater than a model expects. The primary outcome is summarized with a standard deviation, and the reported variation differs across arms. The registry does not identify an over-dispersion model or a variance adjustment. Consequently, no such method should be inferred from the posted summaries.

11. Confidence Intervals and Precision

The sponsor-reported primary ANCOVA contrast for ranibizumab alone versus PRP alone was -2.8 square millimeters, with a 95% confidence interval from -5.4 to -0.2. For ranibizumab alone versus the combination, the estimate was -1.2, with a 95% confidence interval from -3.8 to 1.5. For PRP alone versus the combination, the estimate was 1.7, with a 95% confidence interval from -1.0 to 4.3.

General explanation: a confidence interval describes the range of estimates reasonably compatible with the observed data under the analysis model and its assumptions. A narrower interval indicates greater precision about the estimated contrast; a wider interval leaves more uncertainty about its size and direction. A 95% confidence interval is not a statement that there is a 95% probability that the particular interval contains the true value.

The first reported adjusted interval lies below zero, whereas the intervals for the other two contrasts include zero. The interval that includes zero does not establish that the groups are identical; it indicates that the analysis does not rule out zero difference at that confidence level. The width of the intervals also shows why a single point estimate should not be read as an exact treatment difference.

The sponsor's adjusted intervals are distinct from the simple unadjusted recalculations. Since the registry record flags a discrepancy between those analyses, the sponsor's analysis is the appropriate source for the reported adjusted comparisons. The registry record does not report a clinically meaningful threshold for the endpoint, so the clinical importance of an interval's magnitude cannot be judged from these statistical results alone.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total event counts. They apply to two-arm comparisons and are illustrations based on the observed effect or a stated fraction of that effect. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The original design assumptions for the trial are not reported in the registry record.

The 80% power column gives the estimated participants per arm for a planning scenario with an 80% chance of detecting the assumed effect under the calculation's assumptions. The 90% power column gives the corresponding participants per arm for a 90% chance. General explanation: power is a design property under a specified effect, variability, significance level, and analysis—not a measure of what happened after a study was conducted.

Each row varies the assumed effect: planning for 100% of the observed effect uses the full observed difference, while planning for 75% or 50% assumes smaller differences. Smaller effects are harder to distinguish from random variation, so they require more participants for the same target power. The figures can therefore increase substantially as the assumed fraction declines. The sample-size illustrations are not observed power.

These calculations use effect estimates from this study, which may be uncertain, particularly when based on modest group sizes. They should be read as conditional planning examples rather than as a recommendation or an account of the choices made when the trial was designed. The registry record does not report the trial's original sample-size justification or planning assumptions.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 3.700; pooled standard deviation σ = 8.453.
2. n = 2 × (1.96 + 0.842)² × 8.453² / 3.700² = 81.9, rounded up to 82 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 3.7                      # observed difference in means
sigma <- 8.45281018360166                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1594281)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 82 (80% power), 110 (90% power)
 75% of observed effect: n per arm = 146 (80% power), 195 (90% power)
 50% of observed effect: n per arm = 328 (80% power), 439 (90% power)
power.t.test: 82.9 
Simulated power at n = 82 per arm: 0.798 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor-reported primary comparisons used ANCOVA and were expressed as least-squares mean differences. For ranibizumab alone versus PRP alone, the reported estimate was -2.8, with a 95% confidence interval from -5.4 to -0.2. For ranibizumab alone versus the combination, it was -1.2, with a 95% confidence interval from -3.8 to 1.5. The comparison between PRP alone and the combination was 1.7, with a 95% confidence interval from -1.0 to 4.3.

Simple unadjusted recalculations from the posted primary means yield different estimates and inferential results for the ranibizumab-alone versus PRP-alone contrast. These recalculations compare group summaries and do not reproduce the ANCOVA model. The registry record flags this discrepancy. In that circumstance, the sponsor's own analysis takes precedence; the unadjusted calculations are best treated as a separate descriptive check, not as a correction to the reported model results.

The registry does not report the covariates, detailed model specification, or reason for the disagreement. It is therefore not possible to determine from the record exactly why the estimates differ. The two analyses should not be blended or presented as if they were the same estimand.

15. Multiplicity, Missing Data and Analysis Populations

The registry record reports one primary outcome and several secondary outcomes, as well as multiple pairwise comparisons among the three groups. It does not report whether the primary pairwise comparisons, secondary outcomes, or repeated assessments were adjusted for multiplicity. The original statistical analysis plan is not reported in the registry record.

General explanation: multiplicity arises when many hypotheses are tested. If each test is interpreted on its own without accounting for the number of tests, the overall chance of observing at least one nominally unusual result can rise. Adjustment methods may control that risk, but they can also affect the precision and interpretation of estimates. Without a documented approach, the reported p-values should be read as the results for their individual analyses, not as a family-wise guarantee.

The primary analysis population is identified as FAS; LOCF, and the record says participants required both baseline and at least one post-baseline measurement. It does not report the number or reasons for missing primary measurements, the pattern of missingness, or sensitivity analyses under alternative assumptions. General explanation: carrying forward a last observation is one way to handle unavailable follow-up values, but its validity depends on assumptions about subsequent outcomes. The record does not provide enough information to assess those assumptions.

Detailed ANCOVA covariates and model diagnostics are not reported in the registry record. Nor are interim analyses, stopping rules, or the trial's original sample-size justification reported. These omissions constrain assessment of whether the reported analyses followed a prespecified plan and how robust the estimates are to modeling and missing-data choices. They do not invalidate the recorded results, but they limit the detail with which the results can be independently evaluated.

16. 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: diabetic retinopathy (left eye) (10.0%), diabetic foot (non-ocular) (8.3%), vitreous haemorrhage (right eye) (8.0%), diabetic retinopathy (right eye) (5.6%), cerebrovascular accident (non-ocular) (5.6%).

The registry reports serious adverse events and other adverse events for two periods: through Month 12 and from Month 12 to 24. Through Month 12, serious adverse events affected 8 of 35 at risk in the ranibizumab-alone group, 11 of 35 in the PRP-alone group, and 16 of 36 in the combination group. The corresponding other adverse event counts were 34 of 35, 29 of 35, and 34 of 36. Deaths recorded for those groups were 1, 1, and 2, respectively.

From Month 12 to 24, serious adverse events affected 5 of 28 at risk in the ranibizumab-alone group, 5 of 20 in the PRP-alone group, and 11 of 25 in the combination group. Other adverse events affected 21 of 28, 12 of 20, and 21 of 25, respectively. No deaths were recorded in these later-period groups.

These are descriptive counts, not adjusted comparisons. The at-risk denominators differ by group and period, and the record does not provide a causal analysis attributing events to treatment. Serious adverse event terms listed across the record include diabetic retinopathy, diabetic foot, vitreous haemorrhage, cerebrovascular accident, and heart valve stenosis. The event figures do not by themselves establish comparative safety or causation.

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

The results describe changes in measured neovascularization area among participants analyzed in this randomized, open-label study. The sponsor-reported ANCOVA estimate for ranibizumab alone versus PRP alone had a 95% confidence interval that excluded zero. The intervals for the two other reported pairwise contrasts included zero. These comparisons are estimates subject to uncertainty, and the record does not report a multiplicity adjustment or the complete model specification.

They do not establish that any strategy is effective or ineffective. The primary endpoint is a surrogate measurement of neovascularization area, and the registry does not state a threshold for a clinically important change. Group means also conceal individual variation. The study's open-label design and the analysis details missing from the registry should be considered when interpreting the findings.

The registry record describes a Phase 2 proof-of-concept study with a listed enrollment of 107. The primary endpoint analysis counts are smaller and outcome-specific; those counts should not be mistaken for the full enrollment. The posted data therefore characterize a particular study and analysis population, not every patient with PDR or every treatment setting.

General explanation: statistical uncertainty and clinical importance are separate questions. An estimate can be statistically distinguishable from zero without being large enough to matter clinically, while an uncertain estimate may still be compatible with differences that deserve further investigation. Because the record supplies no clinical threshold and does not report a complete analysis plan, the results support a careful description of the observed comparisons rather than a broad conclusion about treatment choice.

18. Why This Trial Matters Statistically

This trial is statistically informative because it compares three active strategies in a randomized parallel-group design and uses a continuous imaging-based endpoint. The arm summaries make variation visible as well as average change, while the sponsor's ANCOVA analyses provide adjusted pairwise estimates with confidence intervals. The registry also records a Month 3 assessment and secondary outcomes addressing visual acuity and retinal thickness.

The study is also a useful example of why analysis method matters. A direct recalculation from group summaries does not reproduce the sponsor's adjusted comparison for the primary endpoint. Raw group means and model-based contrasts answer related but not necessarily identical questions. Reporting both without distinction could confuse readers, so the discrepancy and precedence of the sponsor analysis matter for interpretation.

The record also illustrates the limits of a p-value-centered reading. Confidence intervals convey the range of estimates compatible with the model, while the absence of reported multiplicity procedures, model details, and missing-data sensitivity analyses limits what can be concluded from the collection of tests. The sample-size illustrations show how planning needs depend on the assumed effect size, but they do not reveal the rationale used for the original design.

These features matter to clinical researchers because they emphasize that a trial result is a combination of endpoint choice, analysis population, model, precision, and reporting completeness. A transparent account of each helps readers distinguish recorded evidence from uncertainty and from questions that the registry record does not resolve.

19. 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 study was open-label, with no masking. That design can affect measurements or decisions where assessment is susceptible to knowledge of assigned treatment; the record does not describe additional safeguards for the primary endpoint beyond central reading of fluorescein angiography images.

The primary endpoint analysis used LOCF and required a baseline and at least one post-baseline measurement. The registry does not report missing-data counts, reasons, sensitivity analyses, or the assumptions supporting LOCF. The analysis population counts are outcome-specific and differ from the enrollment figure, but the record does not explain all differences.

The sponsor's ANCOVA estimates cannot be independently reconstructed from the registry because covariates and model details are not reported. The registry flags a discrepancy between sponsor analysis and the simple unadjusted recalculation; the sponsor analysis takes precedence, but the reason for the discrepancy is not reported. Multiplicity procedures for the several pairwise and secondary analyses are also not reported.

The primary outcome is an imaging measure, and a clinically important difference threshold is not reported. The study is described as Phase 2 and proof-of-concept, and its findings should be understood in that context. The original sample-size justification, interim analyses, and detailed statistical plan are not reported in the registry record. These limitations restrict evaluation of precision, robustness, and the extent to which all reported analyses were prespecified.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Multicenter 12 Months Clinical Study to Evaluate Efficacy and Safety of Ranibizumab Alone or in Combination With Laser Photocoagulation vs. Laser Photocoagulation Alone in Proliferative Diabetic Retinopathy (PRIDE) — NCT01594281.
• Registry record last updated 2019-03-15; status last verified 2018-11.
• Results first posted 2019-03-15.
• 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.

23. Record Summary

NCT01594281 was a completed, randomized, open-label, parallel-group Phase 2 study sponsored by Novartis Pharmaceuticals. It compared ranibizumab alone, PRP alone, and ranibizumab plus PRP in proliferative diabetic retinopathy. The registry lists enrollment as 107 and describes the study as a 12-month proof-of-concept trial.

The primary outcome was change from baseline in neovascularization area at EOCS, measured from fluorescein angiography. Sponsor-reported ANCOVA comparisons are recorded alongside group means and standard deviations. The registry flags a discrepancy between those analyses and simple recalculations, so the sponsor's analysis takes precedence.

The record also lists secondary clinical and imaging outcomes and adverse event counts through Month 12 and from Month 12 to 24. Multiplicity procedures, complete model details, missing-data sensitivity analyses, and the original sample-size justification are not reported in the registry record.