Sunitinib for Metastatic Renal Cell Cancer With Imaging Biomarker Assessments for the Early Prediction of Tumor Response: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sunitinib for Metastatic Renal Cell Cancer With Imaging Biomarker Assessments for the Early Prediction of Tumor Response (NCT00694096), a na phase 1 study. The primary outcome is Metabolic Response.

2. Clinical Question

The broader study question was exploratory: whether a set of imaging assessments could identify one or more candidate biomarkers for early prediction of tumor response. The planned imaging domains included tumor metabolism, proliferation, blood flow, perfusion and blood volume. The summary describes baseline imaging followed by an assessment at 1 week, 2 weeks, 3 weeks or 4 weeks. It does not establish that any imaging measure predicts later clinical outcomes, and the registry record does not report results establishing such a relationship. Overall survival is listed as a secondary outcome, but its results are not reported in the registry record.

3. Trial Design

The registry identifies this as a Phase 1, completed, single-group study sponsored by the University of Utah. Its stated aim was exploratory imaging biomarker assessment in metastatic renal cell cancer, rather than a randomized comparison of treatment strategies. The enrollment entry is 25. The summary describes a target of 20 evaluable patients for the planned imaging assessments.

All participants received sunitinib. There was no masking, and allocation is listed as not applicable. The summary describes scans at baseline and a post-therapy scan at one of the early time points: 1 week, 2 weeks, 3 weeks or 4 weeks. It states that the imaging schedule was organized with 5 patients at each of those follow-up times. Assessments included dynamic FDG-PET for tumor metabolism, dynamic FLT-PET for proliferation, and PET or MRI measures related to blood flow, perfusion and blood volume.

The primary outcome is titled “Metabolic Response,” with a timeframe of 4 weeks. It is defined as the number of patients achieving at least partial response on follow-up FDG-PET compared with baseline, using EORTC response criteria. The primary outcome population is stated as 19 patients; one patient was removed from analysis after pathologically proven sarcoidosis at the PET imaging location. The registry record does not report the number meeting the response criterion.

Overall survival is listed among the secondary outcomes, but no secondary outcome results are reported in the registry record. The record also does not report a statistical analysis plan, an interim analysis plan or a sample-size justification. Since there is no concurrent control group, the design cannot provide a like-for-like treatment comparison. Its structure is suited to describing within-person imaging changes and generating hypotheses about candidate biomarkers, while leaving treatment effects and predictive performance unresolved.

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: Nineteen patients were included in the analysis. One patient was found to have pathologically proven sarcoidosis at the location of the PET imaging and was therefore removed from analysis.

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 Metabolic Response, measured over 4 weeks.

The primary endpoint is the number of patients achieving metabolic response by 4 weeks. Response is assessed by comparing follow-up FDG-PET with baseline and applying the EORTC criteria to the change in average maximum standardized uptake value (SUVmax). The registry defines partial response as at least a 25% decrease in SUVmax, progressive disease as at least a 25% increase, and stable disease as a change of less than 25%. The endpoint counts patients with at least partial response.

FDG-PET is used in this study to assess tumor metabolism. The study's rationale is that imaging changes soon after treatment may provide candidate indicators of tumor response. Comparing a patient's follow-up scan with that patient's baseline scan makes the outcome a within-person assessment rather than a comparison between separate treatment groups. The endpoint is therefore a classification of metabolic change under the stated criteria, not a direct estimate of the treatment's effect relative to an untreated or alternative-treatment group.

The registry record does not report the observed response count, the distribution across response categories, or an uncertainty interval for the endpoint. It also does not report whether the metabolic classification was associated with overall survival or another clinical outcome. Those omissions mean the endpoint's numerical result and its precision cannot be assessed from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study combines a clinical outcome definition with exploratory imaging measurements. The primary endpoint is a count of patients classified as having metabolic response at the stated follow-up, using FDG-PET and EORTC response criteria. The outcome is binary at the patient level for the main count: a patient either meets the definition of at least partial response or does not. The registry record does not report that count or an uncertainty estimate.

What does a within-person baseline comparison show?

In general, a within-person comparison measures change relative to the same person's starting measurement. It can remove some sources of between-person variation because each participant serves as their own reference for the imaging comparison. It does not, by itself, provide the counterfactual comparison needed to determine what would have happened to those participants without treatment or under a different treatment. In a single-group study, time-related changes and other influences cannot be separated from treatment effects on the basis of the design alone.

Here, follow-up FDG-PET is compared with baseline through the change in average maximum SUVmax. The EORTC thresholds classify the change as partial response, progressive disease or stable disease. Categorizing a continuous imaging measurement makes the result easier to express as a response count, but it also means the classification depends on the defined cut points. The record supplies those definitions but does not report the observed SUVmax changes or response categories.

How should a confidence interval be understood?

In general, a confidence interval describes the statistical uncertainty around an estimate under the assumptions of the analysis. A narrower interval indicates greater precision, while a wider interval indicates less precision. An interval for a response proportion would help show how much uncertainty accompanies the observed response frequency, especially when the analysis population is limited. The registry record does not report a confidence interval for the primary endpoint, so its precision cannot be evaluated from that record.

What does the study design permit?

The registry records a single-group model, no masking and allocation listed as not applicable. There is no randomized comparator. Consequently, any descriptive change from baseline would characterize the participants' observed imaging course, but would not establish a comparative treatment effect. This distinction matters even if a response count or a change in an imaging marker is reported: statistical significance in a within-group analysis would not turn the design into a controlled treatment comparison.

The registry record lists no analyses in its analysis count and does not report the statistical analysis plan. It does not state whether a formal hypothesis test was planned, how uncertainty was to be quantified, or how the several imaging measures and time points would be handled analytically. Those details are not reported in the registry record and should not be inferred from the endpoint description.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability is greater than a statistical model expects. For count outcomes, this can make standard errors too small and confidence intervals too narrow if the model assumes less variability than the data contain. A model that accounts for over-dispersion may therefore change the estimated uncertainty. This is general statistical context; the registry record does not report a count model or an over-dispersion assessment for this study.

How should planning illustrations be read?

In general, a sample-size calculation is a planning aid based on chosen assumptions, not a result observed in participants. The registry's description of its planning illustrations specifies a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation and effects defined as fractions of the observed effect. It also distinguishes participant counts per arm from total event counts for time-to-event outcomes. These are described as planning assumptions, not the trial's own design. They do not constitute observed power, and they do not supply missing outcome results. The record does not report the trial's own sample-size justification.

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("Arm 1 - Sunitinib 37.5 mg")
n      <- c(19)
events <- c(5)
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  Arm 1 - Sunitinib 37.5 mg  19  5  26.3  9.1  51.2  11.8  48.8  11.9  49.1

11. Multiplicity, Missing Data and Analysis Populations

The study examines several imaging domains: metabolism, proliferation, blood flow, perfusion and blood volume. The summary also describes early follow-up at 1 week, 2 weeks, 3 weeks and 4 weeks. Assessing multiple biomarkers and time points creates a multiplicity issue: the more measures or comparisons considered, the greater the general chance of apparently notable findings arising by chance when many tests are performed. This is a general statistical concern, not a claim that a particular adjustment was or was not used.

The registry record does not report a multiplicity strategy, such as a prespecified hierarchy of outcomes or an adjustment to account for multiple comparisons. It also does not report a statistical analysis plan or any analyses in its analysis count. The record therefore does not establish which imaging measures were confirmatory, how comparisons across time points were prioritized, or how inference across the biomarker set was controlled.

The primary endpoint population is stated as 19 patients, with one patient excluded because sarcoidosis was found at the PET imaging location. The record does not fully describe the status of all enrolled participants for the primary analysis, the reasons for any other missing or unevaluable assessments, or the approach to missing data. It does not report whether analyses were based on all enrolled participants, only those with evaluable scans, or another defined analysis population beyond the primary population description.

The planned target of 20 evaluable patients and the enrollment entry of 25 are not enough to infer how missing observations were handled. Without a reported missing-data strategy and outcome results, the potential influence of incomplete imaging data on the endpoint cannot be assessed from 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: syncope (4.0%), infection: urinary tract (4.0%), dehydration (4.0%), obstruction: bowel (4.0%), death (4.0%).

The safety record lists one Sunitinib group with 25 participants at risk for serious adverse events and 5 affected. It separately lists 25 at risk for other adverse events and 20 affected. These are registry counts for the recorded categories; they do not, on their own, indicate how many events each affected participant experienced or whether the same participant appeared in more than one category.

The listed serious adverse event terms are syncope, urinary tract infection, dehydration, bowel obstruction, death and lower-extremity muscle weakness. The registry reports 4.0% alongside each listed term. These percentages should be read as the registry's reported values, not converted into event counts or added together. The record does not specify in this summary whether terms could overlap within participants.

These figures describe adverse-event reporting in a single-group study. They do not provide a controlled comparison of safety, and the registry record does not report a comparison group receiving another treatment or no treatment. The listed serious adverse events are not a complete characterization of all possible risks, and the registry record does not provide enough detail to assess event timing, duration, severity beyond the serious designation, or attribution to treatment. No medical conclusion should be drawn from these counts alone.

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

The study addresses whether early imaging measurements might help characterize response in metastatic renal cell cancer during sunitinib treatment. It includes a specific primary endpoint: the number of patients meeting an FDG-PET metabolic-response definition at 4 weeks. The registry record provides the endpoint criteria and analysis-population description, but does not report the observed response count. Therefore, the posted record does not establish how many patients met the endpoint or the precision of that estimate.

The record also describes a broader exploratory aim of evaluating imaging-derived biomarkers, including measures of metabolism, proliferation, blood flow, perfusion and blood volume. That aim is relevant to the design, but a study objective is not evidence that a biomarker predicts response. The record does not report the results needed to assess a predictive relationship, nor does it report a link between the imaging measures and overall survival.

Because the study has a single group and no randomized control arm, it cannot support a like-for-like comparison of sunitinib with another strategy. A before-and-after imaging comparison can describe change in participants, but cannot by itself establish that treatment caused the change. The registry record does not provide a treatment-effect estimate against a comparator.

The completed status indicates that the study is recorded as completed; it does not mean that all planned analyses or outcomes are reported in the registry. The record lists adverse-event counts and terms, but those data likewise do not establish comparative safety. Overall, the information supports understanding the study's exploratory imaging design and the definition of its primary endpoint, while leaving the numerical endpoint result and its clinical interpretation unreported.

14. Why This Trial Matters Statistically

This trial is statistically notable for treating imaging as an exploratory source of early response information rather than relying only on a later clinical outcome. The registry describes several biological domains, including metabolism, proliferation, blood flow, perfusion and blood volume, assessed around the start of sunitinib treatment. That breadth illustrates an important challenge in biomarker research: a large collection of plausible measurements can generate hypotheses, but interpretation depends on prespecified outcomes, clear analysis populations and transparent reporting.

The primary endpoint operationalizes metabolic response through a defined FDG-PET comparison with baseline and EORTC thresholds. Such definitions make an imaging outcome interpretable and reproducible in principle. However, a threshold-based classification does not supply evidence of prediction by itself. Evaluation of a biomarker as a predictor requires reported results linking the imaging measure to a relevant response or clinical outcome, with uncertainty and analytic methods made clear.

The single-group design is also important for statistical interpretation. It can support descriptive study of early imaging changes, but it lacks a concurrent comparator for estimating a treatment contrast. That limitation is especially relevant when the goal is to distinguish a treatment-related signal from changes that could occur for other reasons.

The registry record leaves the primary response count and analysis methods unreported. It also does not describe a multiplicity strategy for the several imaging measures and assessment times. These omissions make it impossible to judge the magnitude, precision or robustness of any biomarker finding from the record. The study's statistical importance is therefore chiefly in its exploratory framework and in the need for complete outcome and methods reporting when multiple candidate biomarkers are examined.

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 principal limitation for interpreting the posted results is that the registry record defines the primary metabolic-response endpoint but does not report its numerical result. It also does not report a confidence interval or hypothesis test for that endpoint. Without these, neither the observed response frequency nor its statistical precision can be assessed.

The design is single-group, with no randomized comparator. The baseline scan provides a within-person reference, but it cannot replace a control group for estimating what would have occurred under another treatment or without treatment. The study's exploratory biomarker aim should therefore not be read as proof that an imaging measure predicts clinical response.

The study planned multiple imaging domains and early assessment times. The registry record does not report how analyses across these measures and times were prioritized or whether multiplicity was addressed. It also does not report the statistical analysis plan, the handling of missing imaging data, or the reasons for any differences between enrollment and the endpoint analysis population beyond the sarcoidosis exclusion described for one patient.

The primary outcome population is stated as 19 patients, while enrollment is recorded as 25 and the summary describes a target of 20 evaluable patients. The record does not fully reconcile these entries. Overall survival is listed as a secondary outcome without a reported result. The safety information provides counts and listed serious-event terms but does not establish comparative risk. These limitations restrict interpretation to the recorded design, definitions and adverse-event entries.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Sunitinib for Metastatic Renal Cell Cancer With Imaging Biomarker Assessments for the Early Prediction of Tumor Response — NCT00694096.
• Registry record last updated 2015-12-01; status last verified 2015-10.
• Results first posted 2015-12-01.
• 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

NCT00694096 is a completed Phase 1, single-group study sponsored by the University of Utah. It enrolled 25 participants and examined early imaging assessments in metastatic renal cell cancer during sunitinib treatment at 37.5 mg/day. The summary describes baseline imaging and follow-up at 1 week, 2 weeks, 3 weeks or 4 weeks.

The primary endpoint is the number of patients achieving metabolic response by FDG-PET at 4 weeks, using EORTC criteria based on change in average maximum SUVmax. The primary analysis population is reported as 19 patients; one patient was excluded after pathologically proven sarcoidosis at the PET imaging location. The registry record does not report the primary endpoint result. Overall survival is listed as a secondary outcome, with no result reported in the registry record.

The design is exploratory and has no control group. The registry record does not report a statistical analysis plan, multiplicity strategy or sample-size justification.