A Study of INCMGA00012 in Squamous Carcinoma of the Anal Canal Following Platinum-Based Chemotherapy (POD1UM-202): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of INCMGA00012 in Squamous Carcinoma of the Anal Canal Following Platinum-Based Chemotherapy (POD1UM-202) (NCT03597295), a na phase 2 study. The primary outcome is Objective Response Rate (ORR).

2. Clinical Question

3. Trial Design

POD1UM-202, also identified as NCT03597295, is a phase 2, single-group study sponsored by Incyte Corporation. Its stated purpose was to assess retifanlimab in participants with locally advanced or metastatic squamous carcinoma of the anal canal that had progressed after platinum-based chemotherapy. The registry lists 94 enrolled participants and an overall status of completed.

The listed intervention is retifanlimab 500 mg given intravenously every 4 weeks. Masking is recorded as none, and allocation is not applicable. With one treatment group and no listed concurrent control, the design can describe outcomes among participants treated in the study, but it cannot estimate a randomized between-group treatment contrast.

The recorded study start date is 2018-10-08, and the primary completion date is 2020-06-08. The primary endpoint was objective response rate, based on complete or partial response under RECIST version 1.1 as assessed by independent central radiographic review. Its stated assessment period began at Cycle 1 Day 1 and continued every 4 weeks throughout the study, up to approximately 24 months.

The registry lists duration of response, disease control rate, progression-free survival, overall survival, treatment-emergent adverse events, and retifanlimab pharmacokinetic measures among the secondary outcomes. Although the record indicates 10 outcome measures, it lists no analyses. A detailed statistical analysis plan, including any planned interim analyses, is 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: A total of 94 participants with locally advanced or metastatic squamous carcinoma of the anal canal were enrolled in the study and treated with retifanlimab.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set: all participants enrolled in the study who received at least 1 dose of study drug

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: The Full Analysis Set (FAS) included all participants enrolled in the study who received at least 1 dose of study drug.

6. Primary Endpoint

The registry lists the primary outcome as Objective Response Rate (ORR), measured over Cycle 1 Day 1, and every 4 weeks throughout the study, up to approximately 24 months.

The primary endpoint, objective response rate (ORR), is the percentage of participants whose best overall response was complete response or partial response. It uses a prespecified response classification: complete response requires disappearance of target and non-target lesions, with no new lesions; pathological lymph nodes must have a short axis <10 mm. Partial response requires complete disappearance or at least a 30% decrease in the sum of target-lesion diameters from baseline, with no new lesions and no progression of non-target lesions.

ORR is a binary-outcome summary at the participant level: each participant is classified according to whether the response definition was met. As general statistical context, this kind of endpoint can describe the frequency of observed tumor responses without requiring every participant to have the same follow-up duration. It does not, by itself, describe how long a response lasts, whether disease control persists, or how outcomes compare with another treatment.

Independent central radiographic review supplies a defined assessment process for classifying response. The endpoint’s stated assessment window runs from Cycle 1 Day 1, with assessments every 4 weeks throughout the study, up to approximately 24 months, and ends at new anti-cancer therapy or first Progressive Disease. The registry record defines the endpoint and its Full Analysis Set, but does not report the number of participants meeting the response criteria, the ORR estimate, or its uncertainty.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary endpoint count?

ORR is a participant-level binary outcome. Under the registry definition, a participant either had a best overall response classified as complete response or partial response, or did not meet either response category. The endpoint is reported as a percentage of participants. This summary focuses on whether a response occurred at any qualifying post-baseline assessment, rather than on the time a response persisted.

As general statistical context, a binary percentage is usually calculated from a count meeting the definition and a defined analysis denominator. Both are important: the count describes the observed events, while the denominator describes the participants included in the analysis. The registry identifies a Full Analysis Set consisting of enrolled participants who received at least one dose, but it does not report the analyzed denominator, response count, or percentage. No value should therefore be inferred from the enrollment total alone.

How are responses classified?

The primary endpoint relies on RECIST version 1.1, with independent central radiographic review. The registry’s complete-response definition requires disappearance of all target and non-target lesions, no new lesions, and reduction of pathological lymph nodes to a short axis <10 mm. Partial response requires complete disappearance or at least a 30% decrease in the sum of target-lesion diameters relative to baseline, with no new lesions and no progression of non-target lesions.

As general methodological context, standardized criteria make response classifications more consistent by defining what change qualifies. A review conducted independently of the treating team can also provide a distinct assessment process. The record does not describe reviewer procedures beyond identifying independent central radiographic review, so further operational details are not reported in the registry record.

What would an uncertainty estimate mean?

As general statistical context, a confidence interval gives a range of values compatible with the observed data under the method used. It is not a guarantee that the true value lies in that particular interval. For a binary response percentage, the interval helps readers judge how much uncertainty remains around the estimated response frequency. A narrow interval would indicate greater precision than a wide interval, but neither precision nor the response frequency can be assessed without a reported estimate and interval.

The registry record does not report a confidence interval, standard error, or hypothesis test for ORR. Nor does it describe a statistical analysis method for the primary endpoint. Thus, a reader cannot determine from the record whether an interval was planned, which interval method would have been used, or whether any statistical threshold was specified.

What can a single-group study establish?

As general statistical context, a single-group study estimates outcomes among participants who receive the study intervention. It does not provide a randomized comparison with a control group. Differences between observed outcomes and outcomes in another population or an external source would not automatically be causal, because populations, assessment, follow-up, and other factors might differ.

Here, allocation is recorded as not applicable, masking as none, and the model as single-group. These design features describe the structure of the study; they do not show whether an outcome was favorable or unfavorable. Without the primary endpoint result and without a concurrent comparison group, the registry record does not support a numerical comparative treatment effect.

How should planning illustrations be read?

The record describes sample-size calculations as planning illustrations based on an observed effect, not as the trial’s own design. It specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event illustrations, the quantity is a total number of events; for other illustrations, it is participants per arm.

As general statistical context, sample-size calculations describe hypothetical requirements under chosen assumptions. They are not observed outcomes, and they are not observed power. Because POD1UM-202 is a single-group study, an illustration assuming two equally allocated arms does not describe its actual allocation. The registry record does not report the trial’s own sample-size justification or statistical design rationale.

Why can over-dispersion matter?

As general statistical context, over-dispersion occurs when observed variability is greater than a statistical model assumes. If a model does not account for that extra variability, uncertainty estimates can be too small and tests can appear more conclusive than warranted. This issue can arise in some count-data settings; the primary endpoint is instead defined as a percentage based on a binary participant-level classification. The registry record does not identify an over-dispersion model or report a statistical analysis that would allow its use to be assessed.

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("Retifanlimab 500 mg")
n      <- c(94)
events <- c(13)
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  Retifanlimab 500 mg  94  13  13.8  7.6  22.5  8.3  22.2  8.3  22.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple secondary outcomes in addition to the primary ORR endpoint. These include duration of response, disease control rate, progression-free survival, overall survival, treatment-emergent adverse events, and retifanlimab pharmacokinetic measures. When several outcomes are examined, general statistical practice recognizes a multiplicity issue: the chance of at least one apparently notable result can increase as more hypotheses are tested. A prespecified testing hierarchy or adjustment can address some multiplicity concerns, but the approach for this trial is not reported in the registry record.

The record identifies the primary endpoint and its assessment criteria, but it does not report a statistical analysis plan, significance-testing procedure, confidence-interval method, or planned handling of interim analyses. It lists no analyses. This does not establish that no analyses were conducted; it means the registry record does not describe them.

The primary analysis population is defined as enrolled participants who received at least one dose of study drug. The number in that population is not reported. The record does not explain how participants without an evaluable response assessment, missing assessments, withdrawals, or new anti-cancer therapy before assessment were handled in the primary analysis. It also does not specify imputation methods or sensitivity analyses for missing outcome data.

As general statistical context, missing outcomes can affect both the denominator and the interpretation of a response percentage. The consequences depend on why data are missing and how the analysis handles them. Without the number of participants assessed and the handling rules, readers cannot determine how missingness may have influenced the reported endpoint. These details are not reported in the registry record.

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: abdominal pain (4.3%), anaemia (4.3%), urinary tract infection (4.3%), general physical health deterioration (3.2%), pelvic pain (3.2%).

The registry lists 94 participants at risk for the safety group. It records 50 participants affected in the serious adverse event category and 79 in the other adverse event category, with 60 deaths. These are counts from the single treatment group, not comparisons between treatment arms. The record does not provide a concurrent control group against which to interpret them.

The listed serious adverse event terms include abdominal pain, anaemia, and urinary tract infection, each at 4.3%; general physical health deterioration, pelvic pain, and pyrexia, each at 3.2%. These percentages describe the listed terms in the registry record. They do not indicate whether events were judged related to treatment, how long participants were observed, or whether an individual could contribute to more than one term; those details are not reported in the registry record.

As general statistical context, adverse-event counts and percentages depend on definitions, follow-up, and the population included in the safety analysis. They should not be interpreted as a comparative risk estimate without a suitable comparison group and aligned observation periods. The available figures describe recorded safety events in the treated cohort; they do not establish causation or determine the clinical significance of an individual event.

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

The registry record describes a phase 2, single-group study of retifanlimab in participants with squamous carcinoma of the anal canal following platinum-based chemotherapy. It identifies ORR as the primary endpoint and defines response according to RECIST version 1.1, assessed by independent central radiographic review. The record also supplies selected safety counts and lists other outcomes intended for assessment.

However, the primary ORR result is not reported in the registry record. There is no reported response count, percentage, or confidence interval. The posted results therefore do not allow readers to quantify the observed response frequency or its precision. Secondary outcome results are also not reported, so the listed outcomes should not be mistaken for findings.

Even a reported response percentage from this design would describe outcomes in the treated group, not a randomized comparison. A single-group study cannot determine from its own design how outcomes would have differed under another treatment or no study intervention. The absence of a concurrent control also means that the safety counts do not provide a comparative safety estimate.

The record’s enrollment count is not necessarily the primary analysis denominator: the stated Full Analysis Set includes enrolled participants who received at least one dose, and the number meeting that definition is not reported. The handling of missing or unevaluable assessments is also not described. These gaps affect how fully readers can evaluate the primary endpoint.

In short, the registry supports understanding the study’s population, intervention, endpoint definition, and broad design. It does not provide the primary response result or enough analysis detail to assess its magnitude, precision, missing-data sensitivity, or comparative effect. The listed safety figures can be read as descriptive counts, with the limitations of a single treatment group and the details not reported in the registry record.

14. Why This Trial Matters Statistically

This trial raises a clear statistical question: how often did participants in a defined post-chemotherapy population meet standardized criteria for complete or partial response after receiving retifanlimab? Defining ORR through RECIST version 1.1 and independent central radiographic review makes the response concept explicit. The endpoint also distinguishes response occurrence from outcomes such as duration of response, progression-free survival, and overall survival, which address different aspects of the clinical course.

The study’s single-group design is central to statistical interpretation. It can describe outcomes among enrolled participants who received study drug, but it does not create a randomized control contrast. Recognizing that distinction prevents descriptive results from being read as if they estimated a causal difference between treatment options.

The record also illustrates why reporting the result and its uncertainty matters. An endpoint definition alone cannot show how frequently the endpoint occurred. Without an estimate, denominator, or confidence interval, readers cannot assess either response magnitude or precision. Similarly, lists of secondary outcomes do not substitute for numerical findings, and safety counts without a concurrent comparison remain descriptive.

Finally, the record leaves important analysis details unreported, including how missing assessments were handled and whether multiplicity was addressed. These are not merely technical details: they inform how much confidence readers can place in estimates and how to interpret multiple outcomes. The statistical value of the study record therefore lies in its defined question and design, alongside the need to distinguish what is reported from what remains unavailable.

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 most important limitation for interpreting efficacy is that the registry record does not report the primary ORR result. It gives the endpoint definition and assessment schedule, but no response count, estimate, confidence interval, or test result. The record lists secondary outcomes without reporting their numerical results, so those outcomes cannot be evaluated from the information recorded.

The study has a single-group design, with no concurrent comparator listed. Thus, it cannot yield a randomized estimate of the difference between retifanlimab and another treatment. Masking is recorded as none, and response assessment is described as independent central radiographic review; other details of assessment and operational procedures are not reported in the registry record.

The enrollment count is 94, while the primary analysis population is defined as enrolled participants who received at least one dose. The size of that population is not reported. The record also does not state how missing response assessments, participants who were unevaluable, or assessments affected by new anti-cancer therapy were handled. Without those details, the primary endpoint denominator and the potential influence of missingness cannot be assessed.

The registry lists no analyses and does not report the statistical analysis plan, sample-size justification, multiplicity strategy, interim analyses, or methods for calculating uncertainty. The sample-size calculations described as planning illustrations are not the study’s design and should not be interpreted as observed power. Safety counts are descriptive and lack a concurrent comparison. Further details on adverse-event attribution and observation periods are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of INCMGA00012 in Squamous Carcinoma of the Anal Canal Following Platinum-Based Chemotherapy (POD1UM-202) — NCT03597295.
• Registry record last updated 2025-08-21; status last verified 2025-08.
• Results first posted 2021-08-23.
• 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

NCT03597295, POD1UM-202, is a completed phase 2, single-group study sponsored by Incyte Corporation. It enrolled 94 participants with squamous carcinoma of the anal canal following platinum-based chemotherapy and evaluated retifanlimab 500 mg intravenously every 4 weeks. The recorded study start date is 2018-10-08, and the primary completion date is 2020-06-08.

The primary endpoint was ORR, defined as complete or partial response under RECIST version 1.1 by independent central radiographic review. The record defines the Full Analysis Set as enrolled participants who received at least one dose, but does not report the primary endpoint estimate or its uncertainty. It lists several secondary outcomes and selected adverse-event counts, but no analyses are listed. The statistical analysis plan and handling of missing data are not reported in the registry record.