A Study of Setanaxib Co-Administered With Pembrolizumab in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of Head and Neck (SCCHN): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Setanaxib Co-Administered With Pembrolizumab in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of Head and Neck (SCCHN) (NCT05323656), a randomized phase 2 study. The primary outcome is Best Percentage Change in Tumour Size.

2. Clinical Question

The comparison is an add-on-treatment question: both groups received pembrolizumab, and random assignment distinguished the added setanaxib from placebo. The primary outcome captures the best observed percentage change in tumour size over the specified assessment period, rather than a single measurement at one fixed visit. The registry lists that period as baseline to at least 15 weeks and up to 51 weeks.

The clinical question is therefore narrower than whether pembrolizumab itself changes tumour size, because pembrolizumab was common to both groups. The study concerns the additional effect associated with assigning setanaxib in this particular trial population and treatment setting. It does not, by itself, answer questions about other diseases, treatment combinations, or outcomes beyond those measured and reported in the registry record.

3. Trial Design

This was a phase 2, randomized, double-blind, placebo-controlled, parallel-group study sponsored by Calliditas Therapeutics Suisse SA. Its registry title describes the combination of setanaxib and pembrolizumab in people with recurrent or metastatic SCCHN. The study is marked completed. The registry lists a start date of 2022-04-06 and a primary completion date of 2024-02-18.

Participants were assigned to one of two groups: setanaxib 1600 mg/day plus pembrolizumab 200 mg, or placebo plus pembrolizumab 200 mg. Pembrolizumab was administered intravenously every 3 weeks. The blinded treatment period was up to 24 months in both groups. Randomization supports a comparison between assigned groups, while double masking and placebo control are design features intended to reduce influences of treatment knowledge on care and assessment. The registry record does not report the precise randomization procedure or details of how masking was maintained.

The primary analysis population is identified as the Full Analysis Set. The primary outcome is a continuous measure of best percentage change in tumour size, with arm-level results for 26 participants in the setanaxib group and 28 in the placebo group. The registry lists 55 participants enrolled; the analyzed group counts should not be treated as interchangeable with enrollment. The reason for any difference between enrollment and outcome counts is not reported in the registry record.

The record lists 21 outcome measures and 13 analyses. It also names secondary outcomes including progression-free survival, disease control rate, overall response rate, duration of response, overall survival, and tumour-tissue measures. The original sample-size justification, detailed statistical analysis plan, and procedures for interim analyses are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set

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 Best Percentage Change in Tumour Size, measured over Baseline to at least 15 weeks and up to 51 weeks.

The primary endpoint is best percentage change from baseline in the sum of diameters of target lesions, assessed using RECIST v1.1. It represents the most favorable percentage change observed during the stated assessment window, which runs from baseline to at least 15 weeks and up to 51 weeks. The primary analysis is described as a least-squares mean analysis in the Full Analysis Set.

A continuous tumour-size measure retains information about the degree and direction of change, rather than reducing each participant to a category such as response or no response. A negative percentage change indicates a reduction from baseline; a positive value indicates an increase. Since the endpoint uses each participant’s best observed change during follow-up, it summarizes the strongest measured change within the window, not necessarily the size at a common final visit.

RECIST v1.1 provides standardized criteria for assessing target-lesion diameters. Standardization helps make tumour measurements more consistent across participants and assessments. The endpoint is used to compare the groups on a prespecified tumour-size measure, but it is not the same as a direct measure of survival, symptoms, or quality of life. Those outcomes require separate assessment. The registry record does not report additional detail about handling participants who lacked a post-baseline assessment or about the exact visit-level rules used to identify the best change.

7. Results Posted in the Registry

• Setanaxib 1600 mg and Pembrolizumab 200 mg: mean -7.88 versus -12.93 on control; difference 5.05 (95% CI -20.32 to 30.42), standardized effect d = 0.11; z-test p = 0.696.

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.

Progression Free Survival (PFS)

• Endpoint type: Time to event: compared as a hazard ratio.
• Test: Hazard ratio as reported by the sponsor (Regression, Cox); it was not recalculated.
• Result:
  • Setanaxib 1600 mg and Pembrolizumab 200 mg: hazard ratio 0.58 (95% CI 0.38–0.89), reported p = 0.102 (as reported in the registry).
• Interpretation:
  • The 95% confidence interval includes no difference (a ratio of 1), so these data do not show a statistically significant difference between Setanaxib 1600 mg and Pembrolizumab 200 mg and the control. The interval gives the range of effects that remain compatible with the data.

Disease Control Rate (DCR)

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Setanaxib 1600 mg and Pembrolizumab 200 mg: 70.4% (19/27) versus 50.0% (14/28) on control; risk difference 20.4 percentage points (95% CI -4.9 to 45.7), risk ratio 1.41 (0.90–2.19); unadjusted two-proportion z-test p = 0.123.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Setanaxib 1600 mg and Pembrolizumab 200 mg and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes broaden the assessment beyond best tumour-size change. Progression-free survival describes time until disease progression or death under the trial’s outcome definition, while disease control rate is a proportion-based measure. The numerical estimates for these outcomes point in a direction favoring the setanaxib group, but each carries uncertainty and they do not establish the primary outcome comparison.

The registry also lists outcomes addressing response, duration of response, overall survival, and tumour-tissue measures, including cancer-associated fibroblasts, CD8+ tumour-infiltrating lymphocytes, and regulatory T-cells. The available numerical details do not cover all listed outcomes, so the broader secondary-outcome pattern cannot be fully evaluated from the registry record. Results not included in the posted numerical details are not reported in the registry record.

Secondary outcomes can support interpretation by showing whether different measures tell a broadly consistent story, but they often involve multiple comparisons. When many outcomes are examined, the chance of observing an apparently notable result by chance can increase. Unless multiplicity is addressed through a prespecified strategy, individual secondary p-values are less persuasive as confirmatory evidence. The registry record does not report a multiplicity adjustment or a hierarchy for testing secondary outcomes.

Secondary estimates are also not necessarily independent of the primary outcome, and they may use different populations, scales, follow-up periods, or statistical models. A directional pattern across selected outcomes is useful context, but it does not erase uncertainty in the primary comparison or establish a causal effect on outcomes that were not adequately assessed.

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

• Progression Free Survival (PFS)
• Change From Baseline in Cancer-associated Fibroblasts (CAFs) Level in Tumour Tissue
• Change From Baseline in the Number of Cluster of Differentiation 8 (CD8+) Tumour Infiltrating Lymphocytes (TILs) in Tumour Tissue
• Change From Baseline in the Number of Regulatory T-cells in Tumour Tissue
• Overall Response Rate (ORR)
• Duration of Response (DoR)
• Disease Control Rate (DCR)
• Overall Survival (OS)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous, so the reported arm results are least-squares means with standard errors. A least-squares mean is an estimate from a statistical model; it can differ from a raw arithmetic average when the model accounts for other variables. The registry’s sponsor analysis identifies ANCOVA as the method for the primary comparison. ANCOVA compares group outcomes while adjusting for covariates included in the model. Which covariates were included is not reported in the registry record.

What does the mean difference express?

The mean difference is the estimated contrast between the setanaxib and placebo groups on the percentage-change scale. The reported difference is 5.05. The direction depends on the order of groups in the contrast. Since the endpoint is a percentage change, negative arm estimates correspond to reduction from baseline, and a less negative estimate is not the same as a greater reduction. The difference is an estimate, not a count of participants who experienced a particular response.

The recalculated comparison uses posted arm-level summary statistics and is unadjusted. It gives a mean difference of 5.05, a confidence interval from -20.32 to 30.42, and an unadjusted p-value of 0.696. This kind of calculation is useful as a transparent summary-based check, but it cannot reproduce an adjusted model without the participant-level data and model specification. In this case the registry record does not flag a discrepancy. The sponsor’s ANCOVA result remains the trial’s reported analysis.

Why are there different confidence intervals?

The registry’s ANCOVA result reports an 80% confidence interval from -11.98 to 22.0, with p = 0.701. The summary-based recalculation reports a different interval, from -20.32 to 30.42. The analysis methods and interval levels are not the same, so the endpoints need not match. Confidence intervals describe uncertainty around an estimate under the assumptions of the analysis; they are not guarantees that the true effect lies inside a particular interval.

The arm-level standard errors are 9.323 for setanaxib and 8.977 for placebo. A standard error describes the estimated sampling variability of an estimate, not the spread of individual participant outcomes. The reported summary-based pooled standard deviation is 47.52 and is marked as approximate. Over-dispersion is a general concern when the variability in data is greater than a model assumes; it can make standard errors and resulting inferences unreliable if not appropriately handled. The registry record does not report a dedicated over-dispersion assessment for the primary endpoint.

How are the secondary outcomes analyzed?

Progression-free survival is a time-to-event outcome. The registry reports a Cox regression hazard ratio of 0.58, with an 80% confidence interval from 0.38 to 0.89 and p = .1023. A hazard ratio compares event rates over follow-up under the model; it is not a direct comparison of median times, and its interpretation depends on the event definition and model assumptions. The record identifies the method as Cox regression, but further diagnostic information is not reported in the registry record.

Disease control rate is a binary outcome expressed as a percentage. The posted arm estimates are 70.4% and 50.0%, and the recalculated risk difference is 0.204, with an interval from -0.049 to 0.457 and unadjusted p = 0.123. A risk difference expresses the contrast in proportions, while its interval conveys uncertainty in that contrast. The record does not list a reported analysis for this outcome in the fields used for this comparison.

For time-to-event outcomes, censoring can occur when follow-up ends before an event is observed. Appropriate survival methods use the available follow-up while accounting for censoring, subject to assumptions about how censoring relates to event risk. The registry lists the PFS timeframe as baseline up to approximately 21 months. More detailed follow-up and censoring rules are not reported in the registry record.

All recalculated comparisons are simple, unadjusted re-calculations from posted summaries. They should be read as descriptive checks rather than replacements for the trial’s own analysis. The record does not provide enough detail to assess every modeling choice, diagnostic, missing-data procedure, or sensitivity analysis.

11. Confidence Intervals and Precision

Precision concerns how much uncertainty surrounds an estimate. A point estimate gives a single summary, while a confidence interval shows a range of values compatible with the data and the specified statistical method. A wide interval indicates that the estimate is not very precise. The interval does not indicate the probability that a fixed treatment effect lies within its bounds.

For the primary outcome, the recalculated mean difference is 5.05, with an interval from -20.32 to 30.42. This range includes zero as well as values in both directions. The posted results therefore do not pin down the size or direction of the between-group difference with much precision. The sponsor’s ANCOVA estimate is also 5.05, with an 80% confidence interval from -11.98 to 22.0. The confidence level differs, and the ANCOVA method differs from the unadjusted recalculation, so those intervals should be interpreted in the context of their respective analyses.

The PFS estimate has an 80% confidence interval from 0.38 to 0.89 for the hazard ratio. The DCR recalculated risk-difference interval runs from -0.049 to 0.457. These intervals convey uncertainty on different scales and for different outcomes. They should not be compared as if they measured the same quantity. An interval for a hazard ratio is interpreted relative to the no-difference value for that measure; a risk-difference interval is interpreted relative to zero difference.

Sample sizes are modest, and uncertainty can remain substantial even when a point estimate appears to favor one group. Confidence intervals also depend on the analysis assumptions and the completeness of the reported information. The registry record does not report all details needed to independently assess those assumptions or the impact of missing observations.

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 illustrations are based on the observed effect and assume a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. They show planning scenarios for detecting the stated fraction of the observed effect. The original trial’s own sample-size assumptions and justification are not reported in the registry record.

For continuous and binary outcomes, the figures are participants per arm. For time-to-event outcomes, the figures are the total number of events, not participants per arm. The 80% power column represents a planning target under which the assumed study would have an 80% chance of detecting the specified effect using the stated test assumptions. The 90% column uses a higher chance of detecting that same effect. These are design concepts, not guarantees about the result of a future study.

The scenarios use 100%, 75%, and 50% of the observed effect. A smaller effect is harder to distinguish from random variation, so it requires more participants or, for time-to-event planning, more events. The displayed figures are based on the observed estimates, which may themselves be uncertain; they should not be read as established requirements for a future trial.

This is not observed power. The calculations are planning illustrations and do not measure the probability that the completed trial detected an effect. They cannot explain the study’s original enrollment target, because that design rationale is not reported in the registry record.

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 = 5.050; pooled standard deviation σ = 47.519.
2. n = 2 × (1.96 + 0.842)² × 47.519² / 5.050² = 1,389.9, rounded up to 1,390 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 <- 5.05                      # observed difference in means
sigma <- 47.5192936067511                     # 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(5323656)
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 = 1,390 (80% power), 1,861 (90% power)
 75% of observed effect: n per arm = 2,471 (80% power), 3,308 (90% power)
 50% of observed effect: n per arm = 5,560 (80% power), 7,443 (90% power)
power.t.test: 1390.9 
Simulated power at n = 1,390 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 analysis is ANCOVA, with a least-squares mean difference of 5.05, an 80% confidence interval from -11.98 to 22.0, and p = 0.701. The summary-based recalculation also estimates a mean difference of 5.05, but gives an interval from -20.32 to 30.42 and an unadjusted p-value of 0.696. The matching point estimate does not make the analyses interchangeable: one is the trial’s adjusted model, while the other is an unadjusted calculation from posted summary statistics, and their confidence intervals differ.

The registry record does not flag a discrepancy between the results. The sponsor’s analysis is the trial-reported result and should take precedence as the study’s own analysis. The recalculation can help readers see how the arm-level summaries relate to a simple contrast, but it cannot reproduce the ANCOVA model or its covariate adjustments. The covariates and further model details are not reported in the registry record.

Both analyses leave substantial uncertainty around the estimated primary contrast. The interpretation should therefore focus on the scale and precision of the estimates, not on treating the recalculation as a replacement for the sponsor’s model.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study analyzes several outcomes, time points, subgroups, or contrasts. Even if each statistical test is conducted at a conventional error rate, testing many hypotheses can increase the chance that at least one result appears notable by chance. The registry lists 21 outcome measures and 13 analyses, along with a range of secondary outcomes. How the study controlled the overall risk of false-positive findings is not reported in the registry record.

The registry identifies a primary outcome, which helps distinguish the main trial question from supporting or exploratory questions. However, the record does not report whether secondary outcomes were organized in a testing hierarchy, adjusted for multiplicity, or treated as exploratory. Without those details, secondary p-values should be interpreted cautiously and should not be treated as independent confirmation of the primary result.

Missing data can also affect estimates. Participants may lack later measurements because of discontinuation, disease progression, death, or other reasons. The registry record identifies the primary population as the Full Analysis Set, but the rules for inclusion in that set, missing outcome handling, and sensitivity analyses are not reported in the registry record. It is therefore not possible to assess from the registry summary whether the reported estimates depend on assumptions about unobserved outcomes.

For time-to-event outcomes, censoring is distinct from ordinary missingness: a participant may contribute follow-up until the last known time without an observed event. The method and assumptions used for PFS are identified as Cox regression, but further details on censoring rules and diagnostics are not reported in the registry record.

The record also does not report the original sample-size justification, interim-analysis procedures, or full statistical analysis plan. Those omissions limit assessment of whether all analyses followed prespecified procedures and how the study addressed multiplicity, missingness, and model assumptions.

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: anaemia (10.7%), colitis (7.4%), hypokalaemia (7.4%), aspiration (7.1%), haemoptysis (3.7%).

The registry reports serious adverse events for 8 of 27 participants at risk in the setanaxib plus pembrolizumab group and 10 of 28 participants at risk in the placebo plus pembrolizumab group. It reports other adverse events for 27 of 27 and 23 of 28 participants at risk, respectively. Deaths are listed for 6 and 13 participants, respectively. These are descriptive counts from the registry record; they do not by themselves explain event timing, cause, severity beyond the serious-event classification, or relationship to study treatment.

The record also names serious adverse-event terms with percentages, including anaemia, colitis, hypokalaemia, aspiration, haemoptysis, and diarrhoea. The listed percentages should be read in the context of the registry’s event reporting, not as adjusted comparisons between treatment groups. The record does not provide enough detail to infer that an event was caused by one of the assigned treatments.

Safety counts are not a substitute for a formal comparative safety analysis. Group sizes are limited, and a difference in observed counts alone does not establish a difference in underlying risk. The registry record does not report the detailed exposure-adjusted analyses, event onset information, or attribution needed for a fuller assessment.

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

The results describe a randomized comparison of setanaxib added to pembrolizumab against placebo added to pembrolizumab in recurrent or metastatic SCCHN. The primary endpoint estimates summarize the best percentage change in target-lesion size over the specified assessment window. The posted primary contrast is uncertain, and its interval spans values in both directions. This means the record does not precisely determine the size or direction of a difference on that endpoint.

The secondary results offer additional observations about progression-free survival and disease control, but they have their own uncertainty and are not a substitute for the primary result. The existence of a point estimate in a favorable direction does not prove that the treatment combination caused a benefit. Likewise, an uncertain result does not prove that the groups are equivalent or that no effect exists.

The findings do not establish outcomes for every person with SCCHN or for treatment settings beyond the one studied. The study was phase 2, and the registry enrollment was 55. Results from this trial alone cannot settle questions about effects in other populations, longer follow-up, or outcomes not reported in the record. The safety counts are descriptive and do not establish causation.

Interpretation also depends on information not reported in the registry record, including the detailed analysis plan, missing-data methods, and multiplicity procedures. The posted results should be understood as estimates from this particular study, with their stated precision and limitations, rather than as a definitive treatment conclusion.

18. Why This Trial Matters Statistically

This trial illustrates why a point estimate and its precision need to be read together. The primary mean difference is a single summary, while its confidence interval shows that the data remain compatible with a broad range of possible contrasts. Treating the point estimate alone as decisive would overlook the substantial uncertainty carried by the analysis.

It also highlights the distinction between an adjusted trial analysis and a summary-based recalculation. Both report the same primary point estimate, but they use different methods and produce different intervals. A recalculation can help make a posted result easier to inspect, yet it cannot replace the sponsor’s model or recover details that are not reported.

The add-on design has a clear comparison: pembrolizumab is used in both groups, with setanaxib contrasted against placebo. This focuses the question on the incremental comparison within that combination setting. It does not answer whether pembrolizumab alone is effective, nor does it establish effects outside the studied population.

Finally, the study lists multiple secondary outcomes and reports only a portion of the numerical details summarized in the registry record. That makes disciplined interpretation important: secondary signals can inform future research, but they should be weighed against uncertainty, multiplicity, and the absence of complete reporting. The sample-size illustrations likewise show how assumptions about the effect to detect influence planning, rather than what the completed study was powered to detect.

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 registry record contains limited detail for independently evaluating the analysis. It identifies ANCOVA for the sponsor’s primary result but does not report the full model specification, including the covariates used. The primary endpoint summaries are available for 26 participants in the setanaxib group and 28 in the placebo group, while the registry lists 55 enrolled. Reasons for the differences between enrollment and analyzed counts are not reported in the registry record.

The record does not report how missing primary measurements were handled, which participants were included in the Full Analysis Set under the detailed analysis rules, or whether sensitivity analyses tested alternative assumptions. The best-change endpoint is measured over a window from baseline to at least 15 weeks and up to 51 weeks; further details about assessment schedules and incomplete follow-up are not reported in the registry record.

Several secondary outcomes are listed, but numerical results and detailed analysis information are not available for all of them in the posted information used. The approach to multiplicity is not reported in the registry record. This limits the strength of conclusions that can be drawn from secondary findings and prevents a full review of the outcome pattern.

The trial’s original sample-size assumptions, interim-analysis procedures, and detailed statistical analysis plan are also not reported in the registry record. The planning illustrations based on observed effects should not be mistaken for the trial’s original design rationale. Finally, the adverse-event counts are descriptive and do not include the detailed timing, attribution, or exposure-adjusted comparisons needed to assess safety differences fully.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: A Study of Setanaxib Co-Administered With Pembrolizumab in Patients With Recurrent or Metastatic Squamous Cell Carcinoma of Head and Neck (SCCHN) — NCT05323656.
• Registry record last updated 2025-09-02; status last verified 2025-08.
• Results first posted 2025-05-09.
• 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

NCT05323656 is a completed phase 2 randomized, double-blind, placebo-controlled parallel-group study of setanaxib plus pembrolizumab versus placebo plus pembrolizumab in recurrent or metastatic SCCHN. The registry lists 55 participants enrolled. The primary outcome was best percentage change from baseline in the sum of target-lesion diameters, assessed by RECIST v1.1, in the Full Analysis Set.

The sponsor-reported ANCOVA estimate for the primary comparison was 5.05, with an 80% confidence interval from -11.98 to 22.0 and p = 0.701. A summary-based unadjusted recalculation gives the same point estimate but a different interval and p-value. Secondary numerical results include progression-free survival and disease control rate. The record also reports adverse-event counts, but the posted information does not establish causation. Important details about the original sample-size rationale, missing-data handling, multiplicity, and full analysis plan are not reported in the registry record.