Trial Using Gilotrif for Advanced Penile Squamous Cell Carcinoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Trial Using Gilotrif for Advanced Penile Squamous Cell Carcinoma (NCT02541903), a na phase 2 study. The primary outcome is Number of Participants With Progression Free Survival at 6 Months.

2. Clinical Question

3. Trial Design

This was a phase 2, single-group study of Gilotrif in advanced penile squamous cell carcinoma following systemic therapy. The sponsor was the University of Alabama at Birmingham. The registry lists an enrollment of 8 and the study status as terminated. The recorded start was 2015-10, and primary completion was 2019-01-26. These registry dates describe the study record; they do not, by themselves, explain when or why the study was terminated.

The study had no listed allocation process and no masking. A single group means that participants assigned to the study treatment were not compared with a separate randomized control group in this design. The registry record therefore cannot support a like-for-like between-group treatment contrast. The reason for termination and any details of the decision to stop are not reported in the registry record.

Gilotrif was to be taken orally at 40 mg once daily, with 4 weeks of continuous treatment considered one cycle. The treatment description says therapy would continue until progression or severe toxicities. It mentions routine blood collections each cycle. The description ends during its account of imaging, so the full imaging schedule is not reported in the registry record. The record also does not report adherence, treatment exposure, dose changes, or the number of participants who began treatment.

The primary endpoint was a count of participants with progression-free survival at 6 months following study treatment. Response rate, overall survival, and toxicities are listed as secondary outcomes. No statistical analysis is listed. The record does not report a protocol, a sample-size justification, planned interim analyses, or details of the analysis populations. Those omissions limit what can be concluded about how the study was intended to handle the small enrolled group and the participant who died before receiving treatment.

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: 1 participant expired before receiving treatment

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: 1 patient expired after signing consent but before starting treatment

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Progression Free Survival at 6 Months, measured over 6 months following study treatment.

The primary endpoint was the number of participants with progression-free survival at 6 months following study treatment. It is a participant count, rather than a continuous measure such as time in days. In general, a fixed-time endpoint summarizes whether each participant has remained free of the defined progression event through a specified follow-up point. It can give a clinically interpretable snapshot, but it does not describe the full timing of events outside that point.

For this study, the registry definition says that death signifies the time of progression-free survival. Otherwise, disease progression was to be evaluated under RECIST version 1.1. The listed definition includes a 20% increase in the sum of the longest diameter of target lesions, a measurable increase in a non-target lesion, or the appearance of new lesions. This makes the endpoint dependent on both the event definition and assessment of disease over follow-up.

A fixed-time progression-free survival measure is used to summarize how many participants meet the event-free condition at a named follow-up point. In general, the interpretation requires knowing who was assessed, how deaths and progression were handled, and how missing or incomplete follow-up was treated. The registry record does not report the endpoint count, an estimate of the proportion, a confidence interval, or an analysis method. It therefore describes the endpoint but does not report the study's observed six-month outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Only the primary outcome definition and a small amount of design information are available in the registry record. The primary measure is a count of participants with progression-free survival at 6 months following study treatment. The record does not report the corresponding count, a confidence interval, a p-value, or a statistical analysis. The explanations below describe general statistical concepts and do not imply that a particular unreported method was used in this study.

What does a participant count represent?

The primary measure is classified as a binary outcome expressed as a count: each participant either meets the defined six-month condition or does not. In general, binary outcomes can be summarized by the number of participants with the event and the number assessed. The count alone does not show the event rate unless the relevant denominator is also known. A denominator also requires a clear definition of which participants are included and how missing outcome data are handled. The registry record gives an enrollment of 8 and notes that 1 participant expired before treatment, but does not report the primary outcome count or the analysis population.

A count at a fixed time point also differs from a time-to-event analysis using the full follow-up. A fixed-time summary focuses on the status at 6 months. A time-to-event analysis generally uses the times at which events occur and can account for varying follow-up, subject to assumptions and specified methods. The registry record names progression-free survival at 6 months as a count and does not report a time-to-event analysis for the primary endpoint. No additional method should be inferred from the endpoint wording alone.

How is progression-free survival defined?

The registry definition states that death signifies the time of progression-free survival. Otherwise, RECIST version 1.1 was to be used to evaluate disease progression. The definition lists a 20% increase in the sum of the longest diameter of target lesions, a measurable increase in a non-target lesion, or the appearance of new lesions as progression criteria. These rules establish what events qualify under the registered definition. In general, consistent event definitions help make outcomes interpretable, but they do not replace reporting how events were observed, adjudicated, and analyzed. Such details are not reported in the registry record.

For a fixed-time measure, participants need sufficient outcome information to determine their status at the stated follow-up point. In general, incomplete follow-up can make status unknown rather than event-free. Different approaches to missing status can change an estimate, so the planned handling should be stated. The registry record does not report missing-data rules, censoring rules, or the status of participants who did not have an assessment at 6 months. It also does not say how the participant who expired before treatment was handled for this endpoint.

What would an uncertainty interval tell a reader?

In general, a confidence interval gives a range of values compatible with the observed data under the assumptions of the statistical method. It communicates precision: a wider interval indicates greater uncertainty in the estimate, while a narrower interval indicates greater precision. A confidence interval does not guarantee that the true value lies within its limits, and it does not remove limitations arising from study design or incomplete data. No confidence interval or primary endpoint estimate is reported in the registry record, so the precision of the six-month result cannot be assessed from this record.

In a small single-group study, an estimate based on a few participants can be sensitive to each participant's outcome. This is a general property of small samples, not a new estimate for this study. Without an endpoint count and a stated denominator, it is not possible to quantify the uncertainty. A single-group result would also remain descriptive of the observed group and would not supply the missing concurrent comparison needed to estimate a between-group treatment effect.

What do the planning illustrations mean?

The planning assumptions describe illustrations computed from an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. For time-to-event illustrations, the calculation is based on the total number of events; other illustrations express participants per arm. These are planning illustrations, not observed trial outcomes and not observed power. The registry record does not report a trial sample-size justification or a randomized two-arm design for this study. Consequently, those generic assumptions should not be mistaken for the design used in this single-group trial.

In general, a sample-size calculation estimates how many observations a future study might need under specified assumptions. It is not evidence that a study had a particular probability of detecting an effect after it has been conducted. In particular, observed power is not a substitute for reporting the estimated outcome and its uncertainty. No study-specific sample-size justification or target tied to a stated effect is reported in the registry record.

What cannot be reconstructed?

The registry record lists 0 analyses and does not provide an inferential statistical plan. It does not report whether any interim analyses were planned, how multiplicity was to be handled, or which participants formed each analysis population. It also does not provide the primary outcome results needed to independently reproduce an estimate. These details matter because an endpoint definition alone does not specify an analysis. Without them, a reader should distinguish the registered question from an answer to that question.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Gilotrif")
n      <- c(7)
events <- c(1)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Gilotrif  7  1  14.3  0.4  57.9  2.6  51.3  3.2  52.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists response rate, overall survival, and toxicities as secondary outcomes, alongside the primary six-month progression-free survival count. It lists four outcome measures in total and 0 analyses. The registry record does not report whether the study planned formal hypothesis tests for these outcomes, an ordering among them, or a procedure for adjusting for multiple comparisons. It also does not report interim analyses. No multiplicity strategy should be inferred from the outcome list alone.

In general, testing multiple outcomes can increase the chance of obtaining at least one apparently notable result by chance. A prespecified analysis plan can explain which outcomes are confirmatory, how comparisons are controlled, and which results are exploratory. In the absence of a reported plan or analysis, the outcome list identifies registered measures but does not establish how results would be interpreted statistically. No such results are reported in the registry record.

The record states that 1 participant expired before receiving treatment. It does not report whether this participant was included in the primary endpoint population, how the participant's outcome was classified, or how the endpoint denominator was defined. It also does not report whether any other participants had missing follow-up or how missing data were handled. For a fixed-time outcome, these details affect whether each participant can be classified at 6 months.

In general, analysis populations should be defined so that readers can understand which participants contributed to each estimate. A registry entry may describe enrollment without detailing the population used for every outcome. Here, the analysis populations, missing-data rules, and any imputation or censoring procedures are not reported in the registry record. The endpoint result is also absent, so the effects of any inclusion or missing-data decisions cannot be assessed.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: fatigue (12.5%), death (12.5%), deep venous thrombosis (12.5%), hospitalization (12.5%).

The registry safety summary lists 8 participants at risk for serious adverse events and 4 affected by serious adverse events. It also lists 8 at risk for other adverse events and 4 affected. The group summary records 4 deaths. These are distinct safety entries in the registry and should be read as reported rather than combined into a new total. The record does not explain the relationship between the deaths entry and the serious adverse event listings.

The top serious adverse event terms are fatigue, death, deep venous thrombosis, and hospitalization, each listed as 12.5%. The registry record does not give further event-level details in the information available, such as timing, severity grades, attribution, or whether a person could appear under more than one term. It also does not explain how the listed percentage for death relates to the group summary of deaths. These entries should not be treated as interchangeable counts or as proof that every listed event had the same clinical circumstances.

In general, adverse event summaries describe events observed during a study and do not, by themselves, establish that the intervention caused them. A single-group safety summary has no concurrent control group for comparison. The counts and terms are a description of what the registry reports, not a comparative estimate of risk.

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

The record documents a phase 2, single-group study of Gilotrif in advanced penile squamous cell carcinoma following systemic therapy. It identifies a six-month progression-free survival endpoint and describes the criteria intended to define progression. It also reports enrollment of 8, termination status, and safety summary entries. Those details describe the study and its registered outcomes.

The record does not report the primary endpoint count, a response-rate result, an overall-survival result, or an analysis of the registered outcomes. It therefore does not show how many participants met the primary endpoint or how precisely any outcome was estimated. A study title, rationale, intervention schedule, and endpoint definition do not substitute for outcome data. The absence of an analysis also means that no reported inferential result can be interpreted from this registry entry.

Because this was a single-group study, it does not provide a randomized comparison with another treatment or a control condition. Even if a within-group outcome were reported, the design would not distinguish the effect of treatment from other explanations for the observed course. The record should not be read as demonstrating a comparative treatment effect.

The safety entries document reported counts and terms, including a group summary of deaths and serious adverse event categories. They do not establish causation, and the registry does not explain how the listed death term relates to the separate deaths count. More detailed event information and an analysis plan are not reported in the registry record.

In general, results are most interpretable when outcome estimates, uncertainty, analysis populations, and methods are reported together. Here, the registered question is clear enough to describe, but the missing endpoint result and analysis details prevent assessment of the observed six-month outcome, its precision, or a treatment contrast. These limits concern what can be concluded from the registry record, not what may or may not have been observed outside it.

14. Why This Trial Matters Statistically

This trial matters statistically as an example of the difference between a registered research question and a reported result. The registry specifies a primary six-month progression-free survival count and a definition based on death or RECIST version 1.1 progression. Yet it does not report the corresponding count or analysis. A well-described endpoint is necessary for interpretation, but it is not evidence about the observed outcome on its own.

The design is also important to interpretation. A single group can describe outcomes among participants receiving a study intervention, but it does not provide a concurrent control estimate. The absence of allocation to a comparator is not a minor reporting detail: it limits the kinds of statistical conclusions the design can support. The registry lists allocation as NA, masking as none, and the model as single group.

The enrollment of 8 and the note that 1 participant expired before receiving treatment make transparent reporting of analysis populations especially relevant. In general, readers need to know how enrollment, treatment initiation, endpoint assessment, and missing follow-up relate to one another. The registry record does not describe those analysis decisions. Without them, a count at a fixed follow-up point cannot be interpreted as a complete estimate for a clearly defined population.

The safety entries illustrate another statistical distinction: descriptive counts are not comparative evidence of causation. Serious adverse event counts and event terms can inform what was recorded in a study, while a single-group design and limited event detail constrain comparisons and attribution. The record also leaves unexplained the relation between the death term and the separate deaths count.

Finally, the study status is terminated, but the reason for termination is not reported in the registry record. Statistical interpretation should avoid filling that gap with assumptions. The record supports careful description of the design, endpoint, enrollment, and safety summary, while making clear that outcome estimation and treatment-effect assessment are not possible from the results listed.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main trial-specific limitation for interpretation is that the registry record does not report the primary endpoint result. Although the endpoint is defined as the number of participants with progression-free survival at 6 months following study treatment, no count, estimate, or confidence interval is listed. The record also lists 0 analyses. Thus, the observed outcome and its precision cannot be evaluated from the registry information.

The study was single group, with no comparator, allocation marked NA, and no masking. This prevents a concurrent like-for-like comparison. The record cannot establish what outcomes would have occurred under another treatment or without the study treatment. The design and absence of analysis details also mean that an effect estimate cannot be interpreted as a causal treatment contrast.

Enrollment was 8, and the registry notes that 1 participant expired before receiving treatment. The record does not report how this participant was handled for the primary endpoint, which participants were included in each outcome analysis, or whether other outcome data were missing. It does not report the number who began treatment, the amount of treatment received, or the completeness of follow-up. These omissions are especially relevant to a fixed-time endpoint requiring status at 6 months.

The treatment description specifies oral Gilotrif at 40 mg once daily and 4 weeks of continuous treatment per cycle, continuing until progression or severe toxicities. However, the description of monitoring is incomplete. Detailed imaging schedules, adherence, dose changes, and event ascertainment procedures are not reported in the registry record. The reason the study was terminated is also not reported.

For safety, the record gives summary counts and serious event terms but not detailed event timing, severity grades, attribution, or an explanation of the relationship between the death term and the group deaths count. It does not report a multiplicity plan, a sample-size justification, interim analyses, or the analysis populations. These limitations restrict interpretation to the information explicitly recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Trial Using Gilotrif for Advanced Penile Squamous Cell Carcinoma — NCT02541903.
• Registry record last updated 2020-04-14; status last verified 2020-04.
• Results first posted 2020-04-14.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes a phase 2, single-group study sponsored by the University of Alabama at Birmingham, evaluating Gilotrif for advanced penile squamous cell carcinoma following systemic therapy. Enrollment was 8. The study is listed as terminated, with a recorded start of 2015-10 and primary completion on 2019-01-26. Masking is listed as none, and allocation is marked NA.

The primary outcome was the number of participants with progression-free survival at 6 months following study treatment, using death or RECIST version 1.1 progression as described in the endpoint definition. The record notes that 1 participant expired before receiving treatment but does not report the primary endpoint count or an analysis. Response rate, overall survival, and toxicities are listed as secondary outcomes.

The safety summary reports 4 participants affected by serious adverse events and 4 affected by other adverse events, with 4 deaths recorded in the group summary. The listed serious adverse event terms are fatigue, death, deep venous thrombosis, and hospitalization, each at 12.5%. The registry record does not report outcome analyses, the reason for termination, or a study-specific sample-size justification.