Clinical Investigation of Galnobax® for the Treatment of Diabetic Foot Ulcers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Clinical Investigation of Galnobax® for the Treatment of Diabetic Foot Ulcers (NCT01113515), a randomized phase 1, phase 2 study. The primary outcome is Safety Outcome.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group, placebo-controlled dose-comparison study in Phase I/II. The registry describes it as triple-masked. The record does not specify which groups of people were masked, how randomization was generated, or how treatment allocation was concealed; those details are not reported in the registry record.

The listed arms were placebo gel, Galnobax 20% once daily, Galnobax 20% twice daily, and Galnobax 14% twice daily. The registry lists enrollment of 44. The group sizes reported with the primary outcome are 10, 9, 14, and 11, respectively. These are the outcome group sizes in the posted results; the record does not explain any difference between enrollment and the analyzed populations, if one existed.

The study record gives a start date of 2014-02-20 and a primary completion date of 2015-06-27, and lists the status as completed. Novalead Pharma Private Limited is identified as the sponsor. The stated purpose was to assess safety and efficacy of the gel formulation in diabetic foot ulcers, including adverse events, wound-closure rates, and the percentage of wounds closed. The primary outcome posted in the results is the number of participants with adverse events through the end of follow-up at Week 25.

The registry does not report the original sample-size justification, planned allocation ratio, detailed eligibility criteria, or protocol deviations. Those omissions limit assessment of how the planned design relates to the posted group sizes and results.

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

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 Safety Outcome, measured over Till end of follow up period (Week 25).

The primary endpoint counts participants who experienced adverse events through the end of the follow-up period, defined in the record as Week 25. The reported unit is participants, and the outcome description refers to the number of participants with adverse events in each group. It is therefore a participant-level count: the posted endpoint does not describe the total number of separate adverse-event episodes or their duration.

As a binary outcome, each participant is classified according to whether an adverse event was recorded during the specified follow-up. In general, this kind of endpoint can summarize how many people experienced at least one event, but it does not by itself show the number, severity, timing, or clinical course of all events. Those details require additional event-level information.

Safety is relevant in a study evaluating a new gel formulation and different dosing regimens. However, the registry record does not give a fuller rationale for selecting this primary endpoint or describe how adverse events were defined, collected, or adjudicated. The broader study description mentions both safety and efficacy, but the posted primary outcome is a safety count. Wound-closure results are not reported in the registry record, so this endpoint alone cannot answer the study’s stated efficacy questions.

7. Results Posted in the Registry

• Galnobax 20% BID: 64.3% (9/14) versus 10.0% (1/10) on control; risk difference 54.3 percentage points (95% CI 23.0 to 85.5), risk ratio 6.43 (0.96–42.98); unadjusted two-proportion z-test p = 0.008.
• Galnobax 14% BID: 54.5% (6/11) versus 10.0% (1/10) on control; risk difference 44.5 percentage points (95% CI 9.7 to 79.4), risk ratio 5.45 (0.79–37.81); unadjusted two-proportion z-test p = 0.031.

8. Statistical Interpretation

9. Statistical Methods Explained

The posted comparison statistics are recalculated, unadjusted summaries based on the group counts. They are useful for understanding the direction and uncertainty of the observed differences, but they do not supply details about the trial’s original analysis plan. The registry record does not report a full statistical analysis plan, a missing-data method, or a prespecified multiplicity procedure.

What does a risk difference describe?

A risk difference compares the proportion of participants with an event in one group with the proportion in another. A value above zero for the Galnobax-versus-placebo comparison means a higher observed event proportion in the Galnobax group; a value below zero would mean a lower observed proportion. The recalculated differences posted for both BID comparisons are positive. They express an absolute contrast on the outcome scale, rather than a relative increase or decrease.

Using a participant-level binary outcome makes this contrast straightforward to interpret: it concerns whether participants were recorded with an event during follow-up. But the estimate is sensitive to the observed counts, especially when group sizes are small. Moving the outcome classification of a small number of participants could materially change the group proportions and their difference. The counts do not establish why events occurred or whether they were related to treatment.

How should a confidence interval be read?

A confidence interval describes statistical uncertainty around an estimate under the assumptions of the method used to construct it. It is not a range containing a known fixed percentage of individual outcomes, and it does not guarantee that the true effect lies inside its endpoints. A broad interval signals that the data are compatible with a range of effect sizes. The risk-difference intervals for both BID comparisons are broad, so the direction of the observed contrast is more precise than its magnitude.

Both recalculated risk-difference intervals lie above zero. That is consistent with the positive observed risk differences and with the unadjusted p-values reported for these comparisons. These statements do not resolve the uncertainty about the size of the difference. They also do not account for a potential multiplicity adjustment; such an adjustment is not reported in the registry record.

What do the p-values say?

A p-value measures how unusual the observed data, or data more extreme, would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true, nor does it measure the importance or certainty of a result. The posted unadjusted p-values are 0.008 for Galnobax 20% BID versus placebo and 0.031 for Galnobax 14% BID versus placebo. They summarize the recalculated comparisons without accounting for the fact that multiple regimens or outcomes may be of interest. The registry record does not report whether the trial used a prespecified testing sequence or adjustment.

Why might relative measures differ from absolute measures?

Risk ratios and odds ratios express contrasts on relative scales, whereas risk differences express absolute contrasts. Relative measures can look large when the comparator event proportion is low, and they can be imprecise when counts are sparse. The posted estimates illustrate this uncertainty: for the 20% BID comparison, the risk-ratio interval extends from 0.962 to 42.98 and the odds-ratio interval from 1.565 to 167.7. For the 14% BID comparison, the odds-ratio interval extends from 0.997 to 117.0. These intervals are wide. The 14% BID odds-ratio interval includes 1, while the corresponding risk-difference interval is above zero; the measures use different scales and should not be treated as interchangeable.

In general, over-dispersion matters when observed variation exceeds what a chosen probability model expects. A model that fails to account for it may understate uncertainty. The registry record does not identify a model-based analysis for these posted comparisons, so over-dispersion cannot be assessed from the reported summaries. The simple recalculations should be read as unadjusted comparisons of posted summary data, not as a reconstruction of an unreported sponsor analysis.

10. Confidence Intervals and Precision

Precision is limited for the posted safety comparisons. The outcome group sizes are 10 for placebo, 14 for Galnobax 20% BID, and 11 for Galnobax 14% BID. The numbers of participants recorded with adverse events are 1, 9, and 6 in those groups, respectively. With group sizes of this scale, the estimates can be sensitive to the experience of individual participants.

The recalculated risk-difference interval for Galnobax 20% BID versus placebo extends from 0.231 to 0.855. The interval for Galnobax 14% BID versus placebo extends from 0.097 to 0.793. Both intervals are above zero, but each covers a broad range of possible differences. Thus, the posted calculations indicate a positive observed contrast while leaving considerable uncertainty about its magnitude.

Relative estimates are also imprecise. The posted risk-ratio estimate for 20% BID is 6.429, with an interval from 0.962 to 42.98. For 14% BID, the estimate is 5.455, with an interval from 0.787 to 37.81. The odds-ratio intervals are likewise broad: 1.565 to 167.7 for 20% BID and 0.997 to 117.0 for 14% BID. Wide intervals are an important part of interpretation, even when a point estimate or p-value attracts attention.

These intervals reflect uncertainty under the recalculation methods; they do not account for unreported features such as missing outcomes, analysis-population definitions, or multiplicity adjustments. The registry record does not report those details. Precision should therefore be judged from both the interval widths and the limited posted information about the analysis.

11. 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 for the two-arm comparisons, not total participants across an entire trial. The registry record’s planning illustration uses a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It uses the observed effect as a starting point and considers detecting the stated fraction of that effect. These are planning assumptions for the illustration; the trial’s own original design assumptions are not reported in the registry record.

For the Galnobax 20% BID comparison, planning for 100% of the observed effect gives 12 participants per arm for 80% power and 15 participants per arm for 90% power. Planning for 75% of the observed effect gives 19 participants per arm for 80% power and 25 participants per arm for 90% power. Planning for 50% of the observed effect gives 38 participants per arm for 80% power and 50 participants per arm for 90% power.

For the Galnobax 14% BID comparison, planning for 100% of the observed effect gives 17 participants per arm for 80% power and 21 participants per arm for 90% power. Planning for 75% of the observed effect gives 27 participants per arm for 80% power and 35 participants per arm for 90% power. Planning for 50% of the observed effect gives 52 participants per arm for 80% power and 69 participants per arm for 90% power.

In plain terms, the 80% and 90% columns describe the per-arm group sizes the illustration estimates would be needed to detect the chosen effect under its assumptions. The higher power target calls for larger groups, and smaller effects need more participants. This is not observed power: it is a planning illustration based on the effects observed in this trial, not a measure of the trial’s achieved probability of detecting an effect.

12. 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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.100; treatment proportion p₁ = 0.643; average p̄ = 0.371.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6833 = 1.3393.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5653 = 0.4758.
4. n = (1.3393 + 0.4758)² / (0.5429)² = 11.2, rounded up to 12 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
p0 <- 0.1                          # control proportion
p1 <- 0.642857142857143                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1113515)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 12 (80% power), 15 (90% power)
 75% of observed effect: n per arm = 19 (80% power), 25 (90% power)
 50% of observed effect: n per arm = 38 (80% power), 50 (90% power)
power.prop.test: 11.2 
Simulated power at n = 12 per arm: 0.851 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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.

13. Multiplicity, Missing Data and Analysis Populations

The posted recalculations compare Galnobax 20% BID and Galnobax 14% BID with placebo. The registry record does not report a multiplicity adjustment, a prespecified hierarchy among comparisons, or a rule for interpreting results across the dosing regimens and outcomes. The p-values are therefore described as unadjusted, and the record does not establish whether they were the only tests planned or performed.

The record lists two secondary outcomes as “Efficacy Outcome,” without providing specific outcome names or quantitative results in the registry record for this analysis. The study description mentions wound-closure rates and the percentage of wounds closed, but corresponding numerical results are not reported in the registry record. The original endpoint definitions, timing details beyond the primary safety timeframe, and efficacy analysis methods are also not reported.

The record does not state how missing observations were handled, whether any participants withdrew, or which analysis populations were used. It does not give a participant flow, an intention-to-treat definition, or a per-protocol definition. The group sizes attached to the primary results are available, but the relationship between those sizes and the broader enrollment figure is not explained. No assumptions about missingness or analysis populations can therefore be verified.

The registry lists zero posted analysis entries, but the record does include summary outcome values and recalculated comparisons. It does not describe an interim analysis plan, stopping rules, or a statistical analysis plan. Those matters are not reported in the registry record; their absence from the record should not be interpreted as evidence that no such procedures existed.

14. 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: arthritis bacterial (7.1%), cellulitis (7.1%), gastroenteritis (7.1%), infected skin ulcer (7.1%).

The serious adverse event figures are participant counts by group. The record reports 0 affected participants in placebo, 0 in Galnobax 20% QD, 4 in Galnobax 20% BID, and 0 in Galnobax 14% BID. The corresponding numbers at risk are 10, 9, 14, and 11. Deaths are recorded as 0 in every group. These figures report counts, not a comparative statistical test, and no confidence intervals or p-values for serious adverse events are posted.

The registry also lists the serious adverse event terms Arthritis bacterial, Cellulitis, Gastroenteritis, and Infected skin ulcer, each with a reported value of 7.1%. The record does not explain the denominator or provide enough detail to connect each term to individual participants or to the group-level affected counts. These term percentages should therefore be read as registry-reported summaries, not as treatment-specific rates.

Serious adverse events are distinct from the primary endpoint’s count of participants with adverse events. The latter is broader; the registry does not provide event-level data to determine how serious and other events overlap. The figures alone do not establish causality or comparative safety.

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

The posted results show that adverse events were recorded among participants in each study group, with higher observed counts in the two BID groups than in placebo. The unadjusted recalculated risk differences for the BID comparisons are positive, and their confidence intervals are above zero. These summaries describe the observed groups during follow-up through Week 25. They do not determine why the events occurred or establish that treatment caused them.

The estimates are imprecise. The group sizes are small, and the risk-difference intervals are broad. The unadjusted p-values summarize the posted comparisons but do not incorporate a reported multiplicity plan. A reader should consider the counts, effect estimates, intervals, and limitations together rather than treating any single statistic as a definitive result.

These safety results do not answer the efficacy question. Although the study description refers to wound closure and other efficacy outcomes, quantitative wound-closure results are not reported in the registry record. The available record also does not describe missing-data handling, analysis populations, or full endpoint definitions. It therefore cannot support a complete assessment of the study’s safety and efficacy evidence.

The serious adverse event counts and the zero death counts add descriptive safety information, but they are not proof that serious events were or were not related to treatment. Nor do the reported counts alone establish equivalence or a clinically meaningful difference between regimens. The study is a Phase I/II investigation with limited group sizes; its posted results should be interpreted as estimates with substantial uncertainty, not as medical guidance or a general conclusion about treatment.

16. Why This Trial Matters Statistically

This study illustrates why a count should be interpreted in the context of its denominator and outcome definition. The primary endpoint records participants with adverse events, rather than the total number of events. That distinction matters because repeated events in a participant are not reflected as additional participants in this endpoint. The separate serious-event summaries provide another view, but the record does not supply event-level data to connect the summaries.

It also illustrates the value of reporting absolute differences alongside relative measures. The risk difference describes an absolute contrast in the proportion of participants with an event; risk ratios and odds ratios describe relative contrasts. With small groups and sparse counts, relative estimates can have very wide intervals. Presenting uncertainty makes clear that a striking point estimate does not necessarily imply precise knowledge of the effect’s size.

The trial is a dose-comparison design with three active regimens and a placebo group, yet the posted recalculated comparisons cover only two active regimens against placebo. The record does not state how multiple comparisons were handled. This creates a useful statistical distinction between calculating a comparison and knowing how it fits into the trial’s prespecified inferential plan.

Finally, a safety endpoint cannot replace efficacy reporting when both aims are stated. The record describes wound closure as part of the study purpose but does not provide numerical efficacy results. Together, these features show why transparent endpoint definitions, group-level counts, uncertainty intervals, analysis-population details, and multiplicity plans are important for interpreting clinical trial results.

17. 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 posted results have limitations specific to this study. Group sizes are limited: the primary outcome lists 10 participants in placebo, 9 in Galnobax 20% QD, 14 in Galnobax 20% BID, and 11 in Galnobax 14% BID. Such small groups make the estimates sensitive to individual outcomes and contribute to wide intervals. The record does not provide participant-level data that would allow independent examination of the event patterns.

The posted recalculated comparisons include only the 20% BID and 14% BID regimens versus placebo. A comparison for the 20% QD regimen is not reported. The record also does not report quantitative results for the stated wound-closure outcomes, so the described efficacy aims cannot be assessed from these results.

Further information needed to evaluate the analysis is not reported in the registry record: detailed eligibility criteria, endpoint definitions beyond the primary description, missing-data handling, analysis populations, the original sample-size justification, and any multiplicity strategy. The record does not say which parties were masked or provide enough event-level information to interpret the serious adverse event terms and their percentages. These gaps limit both the assessment of potential bias and the ability to compare safety summaries across groups.

The trial is listed as completed, but completion status does not resolve these reporting limitations. The posted results should be read as limited summaries of the recorded outcomes, not as a full protocol-level account of trial conduct or analysis.

18. Related Tutorials

19. Related Statistical Calculators

20. Sources

• ClinicalTrials.gov: Clinical Investigation of Galnobax® for the Treatment of Diabetic Foot Ulcers — NCT01113515.
• Registry record last updated 2024-05-20; status last verified 2024-05.
• Results first posted 2024-05-20.
• 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.

21. Record Summary

The registry describes NCT01113515, “Clinical Investigation of Galnobax® for the Treatment of Diabetic Foot Ulcers,” as a randomized, parallel, placebo-controlled Phase I/II study with triple masking. It lists enrollment of 44, a start date of 2014-02-20, primary completion on 2015-06-27, and status as completed. The sponsor is Novalead Pharma Private Limited.

The four listed groups received placebo gel or Galnobax 20% once daily, Galnobax 20% twice daily, or Galnobax 14% twice daily. The primary posted outcome counts participants with adverse events through Week 25. Recalculated unadjusted comparisons are reported for the two BID regimens versus placebo; a comparison for the 20% QD group is not reported. Serious adverse event and death counts are also posted. Quantitative efficacy results and several analysis details are not reported in the registry record.