Study of Cetuximab in Combination With Chemotherapy in Patients With Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck (SCCHN): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of Cetuximab in Combination With Chemotherapy in Patients With Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck (SCCHN) (NCT00971932), a na phase 2 study. The primary outcome is Best Overall Response (BOR) According to Modified World Health Organization (WHO) Criteria.

2. Clinical Question

The study was designed to assess antitumor activity in this clinical setting. Its stated primary objective concerns the combination of cetuximab and chemotherapy, rather than a comparison of cetuximab with chemotherapy alone. Because all participants were assigned to one study group, any response observed in that group would describe outcomes during the combination regimen; the design cannot isolate the contribution of an individual drug.

The registry lists secondary outcomes including best overall response by RECIST criteria, disease control rate, duration of response, progression-free survival, overall survival, and time to treatment failure. These outcomes address different aspects of response and follow-up, but their results are not reported in the registry record. The central statistical question that can be evaluated from the record is therefore how the primary response was defined and what the design can support—not the size or precision of an observed response estimate.

3. Trial Design

This is a phase II, open-label, single-arm, multicenter study. The registry reports enrollment of 33 participants and identifies squamous cell carcinoma of the head and neck as the condition under study. The study concerns first-line treatment of recurrent and/or metastatic disease in Japanese subjects. The record gives a start date of 2009-07 and primary completion of 2011-03, with a status of completed.

Participants received cetuximab in combination with chemotherapy. The arm description names cetuximab with cisplatin/carboplatin and 5-Fluorouracil. The brief summary specifically describes cisplatin plus 5-FU, while the arm listing allows cisplatin or carboplatin. Details explaining how chemotherapy choice was determined, or whether it changed during treatment, are not reported in the registry record.

Open-label means treatment assignment was not masked in the study. The primary response assessment, however, is described as being performed by an Independent Review Committee. Independent review can help separate response assessment from the treating team's judgment, but it does not create a concurrent control group or make the overall study blinded.

The record describes evaluations every 6 weeks until progressive disease, with the stated observation period running from the day the first participant was treated to the cut-off date of 02 March 2011. Enrollment is not the same as the number contributing to each endpoint: the primary population is defined as participants receiving at least one dose, but outcome-specific denominators and participant flow are not reported in the registry record.

There is no randomized allocation because the study has a single group. It therefore estimates outcomes among participants treated under the study regimen, rather than a between-group treatment effect. The protocol's detailed statistical plan, including any planned interim analyses or sample-size justification, 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intention-to-treat (ITT) population included all participants who received at least one dose of the study medication.

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 Overall Response (BOR) According to Modified World Health Organization (WHO) Criteria, measured over Evaluations performed every 6 weeks until progressive disease (PD) reported between day of first participant treated, until cut-off date, 02 March 2011.

The primary endpoint is the percentage of participants with a best overall response of complete response or partial response, assessed using modified World Health Organization criteria. A complete response requires complete disappearance of measurable and evaluable disease without new lesions. A partial response requires at least a 50 percent decrease in the sum of the products of the diameters of index lesions compared with baseline, with no evidence of progressive disease. The response must be confirmed by a subsequent assessment no less than 28 days after response criteria were first met. An Independent Review Committee is identified as the assessor.

Response is used as a measure of tumor shrinkage and disease status during follow-up. Requiring confirmation helps distinguish a response that persists at a subsequent assessment from a single assessment that meets the criteria. The percentage format describes the proportion of the analysis population meeting the response definition; it does not by itself establish how response compares with another treatment or what caused the observed response.

Assessments are described as occurring every 6 weeks until progressive disease. The primary result—the response percentage and its 95% confidence interval—is not reported in the registry record. As a result, the endpoint definition is available, but the observed response and its precision cannot be assessed from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information available in the registry record is limited. It identifies a binary percentage endpoint, a 95% confidence interval, an intention-to-treat population definition, and an Independent Review Committee assessment. The detailed analysis plan, including the statistical model, handling of missing endpoint assessments, and any prespecified decision threshold, is not reported in the registry record. The primary outcome estimate and confidence interval are also not reported.

What does a response percentage describe?

For a binary endpoint, each participant is classified according to whether the defined event occurred. For this endpoint, the event is a confirmed complete or partial response. A percentage expresses the share of the analysis population classified as responders. It is a descriptive summary of the observed group; it does not establish a treatment effect in the absence of a comparison group. The registry's definition of the primary population includes all participants who received at least one dose of study medication.

The response definition combines criteria about change in measurable disease with requirements about new lesions, progressive disease, and confirmation. Complete and partial response are distinct response categories, but both count toward the primary endpoint as described. Confirmation by a subsequent assessment no less than 28 days after the response criteria are first met is part of the endpoint, not a separate outcome.

What does a confidence interval add?

General statistical explanation: a confidence interval represents uncertainty around an estimated quantity under the assumptions of the method used. It provides a range of values compatible with the observed data and the specified procedure, rather than a guarantee about the true value. A narrower interval generally indicates greater precision than a wider interval, while the estimate itself indicates the center of the reported result. Neither the interval nor the point estimate can be interpreted without knowing the analysis population and method.

The registry specifies a 95% confidence interval for the response endpoint but does not report its limits. It also does not identify the confidence-interval method in the record. Therefore, the precision of the response estimate cannot be judged, and no particular interval calculation should be assumed.

Why does the design matter?

In a single-arm study, the principal outcome summary is the result within the enrolled group. There is no concurrent control distribution against which to estimate a randomized difference. An external historical benchmark, if one were used, would require its own justification and assumptions; the registry record does not report such a comparison. The absence of a comparator also means that the observed course cannot be attributed to one component of the combination solely from this design.

The study is open-label, although response is described as assessed by an Independent Review Committee. Independent outcome assessment can reduce dependence on the treating investigator's response judgment. It cannot address all potential differences in care or follow-up, and it does not change the single-arm nature of the evidence.

How should the planning illustrations be read?

General statistical explanation: sample-size calculations depend on a target effect, a chosen significance level, a design, and assumptions about the data. The planning illustration associated with the study uses a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It considers effects expressed as stated fractions of the observed effect. Those assumptions describe the illustration, not this study's single-arm design.

The illustration is not the trial's own sample-size justification, and its values are not observed power. Planning calculations describe what a hypothetical design might require under stated assumptions. They do not show that a study had a given probability of detecting an effect after its results are known. The registry record does not report the protocol's sample-size justification or the planning assumptions used when the study was designed.

The illustration distinguishes participants per arm for ordinary outcomes from the total number of events for time-to-event outcomes. This distinction reflects different statistical inputs: a binary endpoint is based on participant-level event status, whereas time-to-event planning commonly depends on the number of outcome events. These generic planning concepts should not be mistaken for a description of the actual trial, which has one study group.

What can be concluded from the listed analysis information?

The primary outcome is defined, and the record names the intended analysis population and assessor. The registry does not report the analysis procedure in enough detail to reconstruct the primary estimate, assess its assumptions, or determine how unavailable assessments were handled. The record also does not report adjusted analyses, subgroup methods, or interim analyses. No such procedures should be inferred from the endpoint definition or study phase.

General statistical explanation: over-dispersion occurs when observed variability is greater than expected under a model's assumptions. It can make model-based uncertainty estimates too small if the extra variability is ignored. The registry record does not report a model for this primary binary endpoint or evidence that over-dispersion was evaluated, so this concept is general rather than a claim about the study's analysis.

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("Cetuximab + Cisplatin/Carboplatin + 5-Fluorouracil")
n      <- c(33)
events <- c(12)
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  Cetuximab + Cisplatin/Carboplatin + 5-Fluorouracil  33  12  36.4  20.4  54.9  22.2  53.4  22.2  53.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and several secondary outcomes: best overall response by RECIST criteria, disease control rate, duration of response, progression-free survival, overall survival, and time to treatment failure. Having multiple outcomes raises the general statistical issue of multiplicity. When many hypotheses are tested, the chance of at least one apparently notable result can increase unless the testing strategy accounts for the number and relationship of the analyses. The registry record does not report a multiplicity adjustment, testing hierarchy, or other strategy for interpreting multiple outcome tests.

The outcomes also differ in what they measure. A response percentage is a binary summary, while duration of response and time-to-event outcomes concern timing and follow-up. Their results cannot be treated as interchangeable evidence. The registry record does not report the secondary outcome estimates or analysis details, so it is not possible to assess their precision or how multiplicity was handled in practice.

Missing-data methods are not reported in the registry record. The primary population is described as including participants who received at least one dose, but the record does not state how participants without an evaluable response assessment were classified, whether any endpoint observations were missing, or how such observations were handled. Enrollment alone does not answer those questions. The record also does not provide participant flow by outcome.

These omissions matter because the response percentage depends on the analysis population and the treatment of participants whose response status cannot be established. A complete interpretation would need the endpoint denominator, the number of participants assessed, and the prespecified and implemented missing-data approach. Those 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.

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: intracardiac mass (3.0%), diarrhea (3.0%), dysphagia (3.0%), mechanical ileus (3.0%), esophageal fistula (3.0%).

The registry lists 12 of 33 participants as having a serious adverse event in the cetuximab-plus-chemotherapy group. It lists other adverse events for 33 of 33 participants. These are participant counts, not event counts, and the two categories should not be added together: an individual participant may contribute to both categories. The death count is not reported in the registry record.

The serious-event terms listed are intracardiac mass, diarrhea, dysphagia, mechanical ileus, esophageal fistula, and septic shock, each with a reported frequency of 3.0%. These term-specific percentages are presented as registry entries. The record does not give the corresponding participant counts for each term or explain whether participants could have more than one listed event.

These data describe events reported in the study group. With no comparator group, they do not estimate a relative safety difference between treatments. The record does not provide enough detail to assess timing, duration, attribution, severity grading beyond the serious-event classification, or how adverse events were collected. The listed figures should therefore be read as a limited safety description, not a complete comparative safety analysis.

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

The registry record establishes the study question, the single-group design, the primary response definition, and selected safety counts. It does not report the primary response percentage or its 95% confidence interval. It also does not report results for the listed secondary outcomes. Without those efficacy estimates, the magnitude and precision of the observed response cannot be described from the record.

Even if a response estimate were available, the single-arm design would make it a description of outcomes among participants receiving the combination, not a randomized estimate of how outcomes differ from another regimen. The design cannot isolate the contribution of cetuximab from the chemotherapy components. Open-label conduct and independent response review are relevant design features, but independent assessment does not provide a treatment comparison.

The safety entries report serious adverse events in 12 of 33 participants and other adverse events in 33 of 33 participants. They do not show how these outcomes compare with another group, and the death count is not reported in the registry record. The specific serious-event terms each have a listed frequency of 3.0%, but the registry does not provide term-specific counts or further event-level detail.

Accordingly, the record supports a factual account of what the trial set out to measure and how it was organized. It does not support a conclusion about the size of the primary response, the precision of that response, comparative efficacy, or comparative safety. The missing outcome results and analysis details limit both statistical interpretation and any broader inference beyond the participants studied.

14. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and study design need to be considered together. The primary outcome is not simply any observed tumor change: the registry specifies response categories, disease criteria, confirmation at a subsequent assessment, a review committee, and a follow-up schedule. Those details determine which observations qualify as responses and what the reported percentage would mean.

At the same time, a carefully defined outcome does not overcome the limits of a single-arm design. A response proportion can describe the treated group, but a comparative treatment effect requires a basis for comparing outcomes under different treatment strategies. This record does not contain a concurrent control group. It therefore provides a useful setting for distinguishing a response description from an estimate of treatment advantage.

The record also shows why results reporting is essential for statistical interpretation. It gives a confidence-interval measure for the primary endpoint, but does not report the estimate or interval. Without both, readers cannot assess either the response frequency or its uncertainty. Likewise, listing secondary outcomes does not convey their findings, and safety counts without a comparison cannot establish relative risk.

Finally, the study's planning illustration should be kept separate from its actual design. Hypothetical assumptions about equal allocation between two arms do not describe a trial that enrolled one study group. This distinction helps avoid reading planning scenarios as evidence about the participants' observed outcomes or as the trial's original statistical justification.

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 limitation for interpretation is that the primary response result is not reported in the registry record. The endpoint percentage and 95% confidence interval are absent, as are the listed secondary outcome results. This prevents assessment of the observed effect and its precision, regardless of the clarity of the endpoint definition.

The single-arm design has no concurrent comparator and cannot estimate a randomized difference between the combination and another treatment. It also cannot separate the contribution of cetuximab from that of the chemotherapy. The study is open-label, although the primary response is described as assessed by an Independent Review Committee.

The registry's treatment descriptions are not fully aligned in level of detail: the brief summary names cisplatin plus 5-FU, while the arm description lists cisplatin/carboplatin with 5-FU. The record does not explain how that choice was made or provide further regimen details. The primary population definition is available, but outcome-specific denominators, participant flow, and missing-response handling are not reported in the registry record.

Detailed statistical methods are also absent, including the confidence-interval procedure, any multiplicity strategy, and whether interim analyses were planned or conducted. The sample-size justification is not reported. Safety reporting includes participant counts and selected serious-event terms, but does not provide a full account of event timing, attribution, or comparative rates. These limitations constrain interpretation of the posted information; they do not establish what unreported analyses or procedures may have occurred.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study of Cetuximab in Combination With Chemotherapy in Patients With Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck (SCCHN) — NCT00971932.
• Registry record last updated 2014-04-08; status last verified 2014-03.
• Results first posted 2012-08-10.
• 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

NCT00971932 is a completed, open-label, multicenter, single-arm phase II study of cetuximab with chemotherapy for first-line treatment of recurrent and/or metastatic squamous cell carcinoma of the head and neck in Japanese participants. Enrollment was 33. The primary endpoint was confirmed complete or partial response by modified World Health Organization criteria, assessed by an Independent Review Committee, with a 95% confidence interval specified.

The registry record does not report the primary response estimate, its confidence interval, or results for the listed secondary outcomes. It reports serious adverse events in 12 of 33 participants and other adverse events in 33 of 33 participants; the death count is not reported. The absence of a comparator and the missing endpoint results limit conclusions about efficacy and comparative safety.