PEG-Interferon Alfa-2b, Sargramostim, and Thalidomide in Treating Patients With Metastatic Kidney Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for PEG-Interferon Alfa-2b, Sargramostim, and Thalidomide in Treating Patients With Metastatic Kidney Cancer (NCT00090870), a na phase 2 study. The primary outcome is Response Rate.

2. Clinical Question

The registry record describes a Phase II study of PEG-interferon alfa-2b, GM-CSF, and thalidomide in patients with metastatic renal cell carcinoma. Its primary question was to define the response rate among patients receiving the combination. The record does not report response-rate data, so the clinical question is stated but cannot be answered from the posted results.

In general, a response-rate endpoint describes whether patients meet specified criteria for tumor response during a defined assessment period. The specific response criteria and any rules for confirming a response are not reported in the registry record. Those details matter because the criteria determine which observations count as responses and how the rate is interpreted.

The registry lists duration of response, adverse events assessed by NCI CTC Version 2, and progression-free survival as secondary outcomes. Their presence identifies additional topics of interest, but the record does not supply results for them in the information available. Consequently, neither the primary question nor the secondary questions can be answered with estimates from this record.

3. Trial Design

This was a Phase II, single-group study sponsored by the Medical University of South Carolina. The registry lists enrollment of 10 and gives a start date of 2002-04 and a primary completion date of 2010-03. Its status is TERMINATED. The reason for termination is not reported in the registry record.

The intervention was a combination of PEG-interferon alfa-2b, GM-CSF, and thalidomide. The record lists PEG-interferon alfa-2b and GM-CSF as biological interventions and thalidomide as a drug. The arm description names PEG-Intron, BM-CSF and thalidomide. The record does not describe dosing, treatment duration, dose adjustments, or rules for stopping treatment; these details are not reported in the registry record.

Allocation is recorded as NA, masking as NONE, and the model as SINGLE GROUP. Thus, the registry describes a study without a listed concurrent comparison arm and without masking. This design can describe outcomes among treated participants if those outcomes are measured and reported. It cannot, by itself, separate treatment effects from changes that might also occur over time or from differences in the participants who entered the study.

The primary endpoint was response rate. Its stated assessment schedule was while on study, every 4 cycles; while off study, every 3 months for 1 year, then every 6 month for 2 years, then every year. The primary endpoint record explicitly says that data were not collected. Secondary outcomes listed are duration of response, frequency of adverse events assessed by NCI CTC Version 2, and progression-free survival.

The registry record does not describe eligibility criteria, a protocol-defined analysis population, a statistical analysis plan, or a sample-size justification. These omissions limit assessment of how participants were selected, how endpoints were intended to be analyzed, and whether the conduct matched a prespecified plan.

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

Analysis population for the primary outcome, as defined in the registry: Data for this endpoint was not collected

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 Response Rate, measured over while on study, every 4 cycles; while off study, every 3 months for 1 year, then every 6 month for 2 years, then every year.

The primary endpoint was response rate in patients with metastatic renal cell carcinoma receiving PEG-interferon alfa-2b, GM-CSF, and thalidomide. The registry describes the objective as defining response rate and gives an assessment schedule during and after study treatment. However, it explicitly states that data for this endpoint were not collected. There is therefore no reported response count, response-rate estimate, or measure of uncertainty in the registry record.

In general, response rate is used to describe the proportion of an evaluated group whose disease meets prespecified response criteria. It gives a direct summary of observed tumor response under the criteria and assessment procedures chosen for a study. Its interpretation depends on what counts as a response, whether response must be confirmed, how missing assessments are handled, and which participants are included in the denominator. Those details are not reported in the registry record.

Response rate is not the same as duration of response or progression-free survival. These listed secondary outcomes address different aspects of disease course: duration concerns how long a response persists, while progression-free survival concerns time until progression or death under its defined endpoint rules. The registry lists these outcomes but does not provide their definitions or results in the record.

Because primary endpoint data were not collected, there is no statistical estimate to interpret for the principal question. The scheduled assessments do not establish that assessments occurred or that response status was recorded. The registry record does not report response criteria, observed responses, or an analysis population.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins by matching the method to the design and to the information actually recorded. This study is listed as SINGLE GROUP, with allocation NA and masking NONE. There is no concurrent control arm in the registry description. The intended primary endpoint is response rate, but its data were not collected. As a result, statistical methods can be discussed in general, but no response-rate analysis can be reconstructed from the registry record.

What does a response rate estimate?

In general, a response rate is a proportion: the number of participants classified as responders divided by the relevant analyzed group. A complete report needs both the responder count and a clearly defined denominator. It also needs criteria for classifying response, a time point or assessment rule, and a policy for participants without evaluable assessments. These choices affect the estimate. The registry record does not report the response criteria, the analysis population, or any response data, so a numerical estimate cannot be derived.

A confidence interval is a range of values that expresses statistical uncertainty around an estimate under a specified method. For a response rate, its width depends in part on the amount of information and the observed response pattern. Since the response data are unavailable, the record has no interval to interpret. General explanations of confidence intervals do not imply that an interval was calculated for this study.

Why does the single-group design matter?

In general, a single-group study can describe outcomes among participants who receive the intervention. It does not provide a randomized comparison with an untreated or alternative-treatment group. Therefore, even if a response rate had been reported, it would not by itself identify the causal effect of the regimen relative to another option. Random allocation helps make treatment groups comparable on average; this registry record does not describe such an allocation or a comparator.

Masking is recorded as NONE. In general, masking can reduce the influence of expectations on care, assessment, and reporting, depending on which people are masked and how outcomes are measured. The registry record does not specify outcome-assessment procedures beyond the assessment schedule, so the practical implications of the unmasked design cannot be evaluated in detail.

How should the planning illustrations be read?

The planning assumptions describe calculations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is expressed as a stated fraction of the observed effect. These are planning illustrations, not a report of the study's own design choices or a calculation of observed power. The registry describes a single-group study, whereas the planning assumptions use two-arm allocation; that distinction is important when interpreting the hypothetical calculations.

In general, power is a design property calculated for a proposed study under assumed effect, variability, significance threshold, and analysis method. It is not a measure of how convincing a completed result is. A sample-size calculation based on an observed effect is especially dependent on the observed estimate and should not be mistaken for evidence that a trial had adequate power. Sample-size assumptions and results do not repair the absence of the primary endpoint data.

The planning convention also distinguishes time-to-event calculations, which give a total number of events, from other calculations, which give participants per arm. In general, event-driven planning for a time-to-event endpoint depends on the number of observed events, while enrollment needed to obtain those events also depends on follow-up and event occurrence. These are distinct quantities. No trial-specific sample-size justification or analysis plan is reported in the registry record.

What does over-dispersion mean in general?

For a binary endpoint such as response, a simple model may assume that each participant's outcome follows a common probability model and that observations are independent. Over-dispersion means that the observed variability is greater than the model assumes. If present, it can make standard errors too small and confidence intervals too narrow unless the analysis accounts for the extra variation. The registry record does not report a response analysis or a model, so there is no indication that over-dispersion was assessed or relevant to a fitted model in this study.

For time-to-event outcomes such as progression-free survival, general methods account for the timing of events and may also account for participants whose follow-up ends before an event is observed. This is called censoring. To interpret such an analysis, readers need endpoint definitions, follow-up information, and the method used. The registry lists progression-free survival and duration of response, but the endpoint rules, analysis methods, and results are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint, response rate, and secondary outcomes of duration of response, frequency of adverse events assessed by NCI CTC Version 2, and progression-free survival. It also reports four outcome measures and zero analyses. The record does not describe how outcomes were prioritized in analysis beyond identifying the primary endpoint, nor does it report a plan for controlling the chance of false-positive findings across multiple outcome tests. The multiplicity strategy is not reported in the registry record.

In general, multiplicity arises when several endpoints, comparisons, time points, or subgroup analyses are tested. The more opportunities there are to find an apparently notable result, the more important it is to interpret each test in light of the overall analysis plan. Methods may adjust significance thresholds or intervals, or designate some analyses as exploratory. No such method is described for this study, and there are no reported analyses to evaluate.

The primary endpoint explicitly says data were not collected. The registry does not report missingness counts, reasons for missing outcome data, or methods for handling missing values. Without those details, it is not possible to distinguish an endpoint that was never collected from individual missing assessments within a collected endpoint, or to assess how missingness might affect an estimate.

The record does not define an intention-to-treat population, a per-protocol population, or another analysis population. In general, a defined population is essential because it determines who contributes to the numerator and denominator and which treatment exposure is being described. The absence of a specified analysis population, combined with the lack of primary endpoint data, prevents reconstruction of an endpoint analysis.

Interim analyses and stopping rules are not reported in the registry record. The terminated status does not establish why the study ended or whether any interim analysis occurred.

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

The registry record establishes that a Phase II, single-group study of PEG-interferon alfa-2b, GM-CSF, and thalidomide was registered for metastatic renal cell carcinoma, with response rate as its primary endpoint. It also identifies secondary outcomes and an assessment schedule. These entries describe the intended questions and design, not the answers to those questions.

The record states that primary endpoint data were not collected. It therefore does not show an observed response rate, and it does not support a claim that the regimen did or did not produce responses. Absence of reported endpoint data is not a null result and is not evidence of no effect. Nor can a response-rate estimate, uncertainty interval, or statistical significance be inferred from enrollment or from the study's status.

The record also does not provide usable estimates for duration of response, progression-free survival, or adverse-event frequency. In particular, the adverse-event entries with zero participants at risk and zero affected do not establish that no events occurred. The death field is null, which is not a reported count of zero.

Even with complete outcome data, a single-group design would primarily describe outcomes in the enrolled participants. Without a comparator, it would not offer the same protection against confounding as a randomized comparison. The registry record does not provide enough information about eligibility, endpoint definitions, analysis populations, or statistical methods to address these issues further.

The proper interpretation is therefore limited: the record documents the study's planned focus and reports that the primary outcome was not collected. It does not establish benefit, lack of benefit, comparative effectiveness, or a safety profile. Any stronger conclusion would require data and analysis details not reported in the registry record.

12. Why This Trial Matters Statistically

This study illustrates an important distinction in clinical-trial interpretation: a registered research question is not the same as a reported result. The record names response rate as the primary endpoint and gives a schedule for assessment, but it explicitly says that endpoint data were not collected. Without the endpoint observations, readers cannot estimate the primary outcome, describe its precision, or compare it with another group.

The single-group design also matters statistically. Such a study can be useful for describing outcomes in a treated group, but it does not create a randomized control group for estimating a comparative effect. That limitation should be kept distinct from the missing-outcome problem: even a complete descriptive response estimate would not alone establish a causal treatment effect, while the absent endpoint data prevent even that descriptive estimate.

The record further shows why outcome definitions and analysis populations are essential. Response criteria, rules for handling unassessed participants, and the population included in an analysis all affect how a response rate should be read. These details are not reported in the registry record. Secondary outcomes are listed, but the registry does not give their results or analysis methods.

Finally, planning calculations must not be confused with observed findings. The stated planning framework uses assumptions for a hypothetical two-arm design, whereas the actual study is recorded as single-group. Planning illustrations are not observed power and do not fill the gap left by uncollected outcome data.

13. 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 consequential limitation specific to this study is explicit in the primary endpoint record: response-rate data were not collected. The registry therefore gives no primary outcome estimate and no basis for evaluating its precision. The listed assessment schedule does not show that assessments were completed or recorded.

The study is recorded as single-group, with no separate comparator arm, and masking is listed as NONE. These design features limit comparative interpretation. The registry record does not give eligibility criteria, the response criteria, a definition of the analysis population, or rules for handling missing assessments. These details are not reported in the registry record.

The registry lists secondary outcomes but does not report their definitions or results. Adverse-event entries show zero at risk and zero affected in the serious and other event fields, while the death field is null. These fields do not provide a basis for estimating event frequency or concluding that no events occurred.

The status is TERMINATED, but the reason for termination is not reported in the registry record. The record also does not report a statistical analysis plan, sample-size justification, interim analyses, or stopping rules. The planning assumptions described for illustrative calculations use a two-arm allocation framework that differs from the registered single-group model; they should not be treated as the trial's own design plan.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: PEG-Interferon Alfa-2b, Sargramostim, and Thalidomide in Treating Patients With Metastatic Kidney Cancer — NCT00090870.
• Registry record last updated 2018-07-12; status last verified 2018-06.
• Results first posted 2018-07-12.
• 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.

17. Record Summary

The registry record describes NCT00090870, a Phase II, single-group study sponsored by the Medical University of South Carolina. It lists Kidney Cancer as the condition, enrollment of 10, a start date of 2002-04, primary completion in 2010-03, and status TERMINATED.

The intervention combined PEG-interferon alfa-2b, GM-CSF, and thalidomide. The primary endpoint was response rate, assessed on a schedule during and after study treatment. The endpoint record states that data were not collected. Listed secondary outcomes were duration of response, frequency of adverse events assessed by NCI CTC Version 2, and progression-free survival.

The registry records no comparator, allocation as NA, and masking as NONE. It lists four outcome measures and zero analyses. No response-rate result or analysis is available in the registry record, and the reason for termination is not reported.