Tumor Detection Using Iodine-131-Labeled Monoclonal Antibody 8H9: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Tumor Detection Using Iodine-131-Labeled Monoclonal Antibody 8H9 (NCT00582608), a na na study. The primary outcome is Safety and Toxicity is Measured by the Total Number of Participants Affected.

2. Clinical Question

The intervention description lists both 131I-8H9 and 8H9, with unlabeled 8H9 preceding the labeled antibody. The study summary explains that 8H9 was made from mouse white cells and had not previously been given to a human patient at the time described in the record. That background explains the focus on safety, but it does not substitute for an outcome analysis.

Because there is no concurrent control group, observations from this study cannot be used as a direct comparison of detection performance against another method or treatment. The registry record does not report tumor-detection accuracy measures, such as the number of tumors identified or a reference standard against which detection was assessed.

3. Trial Design

The registry identifies this as an open-label, single-group study of 131I-8H9. Masking is listed as none, so the record does not describe blinding. Allocation is listed as NA, and the registry explicitly notes that this is not a randomized comparison and that arms are not a like-for-like control comparison. A separate control arm is not described.

The intervention description says participants received an intravenous injection of 131I-8H9 at 10mCi/1.73m^2, preceded by unlabeled 8H9 at 50mg/1.73m2. The intended specific activity is given as 20mCi/mg protein. These are the regimen details recorded; other administration details are not reported in the registry record.

The study is listed as phase NA. Memorial Sloan Kettering Cancer Center is named as sponsor. The recorded start is 2001-10, primary completion is 2009-05, and status is terminated. The registry record does not state why the study was terminated, so its status should not be taken as evidence about safety, feasibility, or tumor-detection performance.

Enrollment is recorded as 12, while the adverse-event entries separately show participants at risk for the event categories they describe. Those category-specific entries should not be treated as a complete account of enrollment or as a primary-outcome analysis. The registry record does not report the number who completed follow-up, the timing or completeness of assessments, or participant flow through the study.

The planned primary outcome timeframe is 2 years. Whether every participant was followed for that duration, and how incomplete follow-up was handled, are not reported in the registry record. A formal protocol, detailed statistical analysis plan, and sample-size justification are also 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:

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 Safety and Toxicity is Measured by the Total Number of Participants Affected, measured over 2 years.

The primary outcome is titled safety and toxicity measured by the total number of participants affected. Its unit is participants, and its timeframe is 2 years. The description directs readers to adverse-event information for protocol-specific details. In statistical terms, this is a count of participants affected, rather than a measurement of the severity of an event or the total number of events.

A participant-level affected count can give a broad indication of whether safety or toxicity events occurred during the specified follow-up period. It is distinct from counting every event: a participant with more than one event may still contribute once to a measure that counts affected participants. The registry record does not explain whether the primary outcome was intended to include all adverse events, a prespecified subset, or events meeting a particular severity definition.

The primary outcome is relevant to a study introducing an antibody that the summary says had not previously been given to a human patient. However, the record does not post a numerical result for this endpoint, confidence interval, or statistical test. It also does not report a primary outcome analysis population or explain how incomplete follow-up was handled. The serious and other adverse-event entries offer some safety information, but they do not supply the missing result for the stated primary endpoint.

The endpoint is not a measure of tumor-detection accuracy. The registry record does not report how detection was defined, how suspected findings were verified, or a comparison with another detection approach. Those omissions mean the posted endpoint information cannot answer the stated tumor-detection question statistically.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation depends on matching each number to the outcome and group it describes. This record lists a binary outcome type, with the meaning given as participants with an event (counts). The primary endpoint is a participant count, while the adverse-event entries report category-specific counts and percentages. These are related kinds of safety information, but they are not automatically the same endpoint.

What does a participant count tell the reader?

A count of affected participants records whether participants experienced an event under a defined outcome. It does not by itself show how many events each participant had, how severe events were, or when events occurred. If an outcome counts participants rather than events, one participant can contribute to the count even if they experience multiple events. The registry record does not specify the precise rules used to determine who qualified as affected for the primary endpoint.

For the posted adverse-event categories, the record lists participants at risk and participants affected. The category-specific values should be read within their own labels. They do not establish that every participant enrolled was assessed for every category, nor do they explain why the at-risk entries differ from the enrollment entry. Those details are not reported in the registry record.

Why does the study design matter?

A single-group study can describe outcomes observed among participants receiving the study intervention. Without a concurrent comparator, it cannot directly estimate how those outcomes differ from what would have occurred under another intervention or without the intervention. Randomization, when used, helps make comparison groups more comparable on average; it is not described for this study. The registry explicitly cautions that the arms are not a like-for-like control comparison.

Open-label status means masking is listed as none. In general, knowledge of treatment assignment can influence reporting, clinical decisions, or outcome assessment, depending on how an endpoint is measured. The registry record does not describe blinded outcome assessment or procedures that might limit such influences. This is a design consideration, not evidence that bias occurred.

What can a confidence interval contribute?

In general, a confidence interval expresses the statistical precision of an estimate under the analysis assumptions. A narrower interval indicates greater precision than a wider interval, while the interval’s endpoints show a range of values compatible with the data and method. No confidence interval for the primary endpoint is reported in the registry record. Without an estimate and its uncertainty, the reader cannot judge the precision of a primary-outcome effect or distinguish a stable estimate from one that could vary substantially.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability in count data is greater than a statistical model expects. A model that assumes less variability than the data contain can make uncertainty appear smaller than it is. This concern may arise when events cluster within participants or when participants differ in their underlying event risk. The registry record does not report a count model, dispersion estimate, or analysis of event-level data, so no conclusion about over-dispersion can be drawn for this study.

What does the record say about planning assumptions?

The record describes a planning illustration based on a stated fraction of an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For time-to-event outcomes, the described convention is total events; for other outcomes, it is participants per arm. These are planning assumptions, not evidence that this single-group trial was designed with two equally allocated arms. The illustrations are not observed power and should not be read as a retrospective measure of the study’s ability to detect an effect.

The trial’s own sample-size justification and statistical plan are not reported in the registry record. No primary analysis is posted, and the record does not state how estimates were adjusted, whether interim analyses were conducted, or how missing outcomes were treated. Those absences limit what can be inferred about the statistical procedures used.

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("MAB 131-I LABELED 8H9")
n      <- c(5)
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  MAB 131-I LABELED 8H9  5  5  100.0  47.8  100.0  56.6  100.0  54.1  99.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and 0 analyses. It does not report a statistical analysis of the primary endpoint. The record does not describe a prespecified testing hierarchy, adjustment for multiple comparisons, or a plan for interpreting several outcomes together. Multiplicity procedures are therefore not reported in the registry record. With no posted primary analysis, there is no reported set of primary and secondary hypothesis tests to interpret.

The registry record does not report a missing-data method, an analysis population, or the number of participants with complete primary-outcome follow-up. It also does not report whether participants who stopped follow-up were included in any analysis or how they were classified. The primary outcome has a 2 years timeframe, but the record does not establish that each participant had complete observation over that timeframe.

Enrollment is recorded as 12, whereas the adverse-event categories list 5 at risk each. The record does not explain this difference. It would be inappropriate to assume that the at-risk counts represent the full enrollment, that unlisted participants had no events, or that these entries form the primary analysis population. Deaths are not reported in the registry record.

In general, missing outcome data can affect interpretation when the likelihood of missingness is related to health status or events. Without information on follow-up completeness and analysis rules, the direction and magnitude of any such effect cannot be assessed. The posted record does not support a conclusion that missingness was absent or that it was handled in a particular way.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: lymphopenia (60.0%), hypokalemia (40.0%), platelets (20.0%), hypophosphatemia (20.0%), hemoglobin (hgb) (20.0%).

The serious-event entry lists 4 affected participants among 5 at risk in the group titled MAB 131-I LABELED 8H9. The other-event entry lists 5 affected among 5 at risk. The registry lists lymphopenia at 60.0%, hypokalemia at 40.0%, and platelets, hypophosphatemia, and hemoglobin (Hgb) each at 20.0% among the top serious terms.

These figures are descriptive entries, not a comparison with another group. The record does not clarify whether the percentages refer to participants or events, the denominator for each term, or whether participants could contribute to multiple terms. They should not be added together or treated as mutually exclusive categories. The adverse-event entry also does not establish that an event was caused by 131I-8H9.

Deaths are not reported in the registry record. The registry record does not provide further event-level detail, such as timing, severity grades, duration, or the method used to determine attribution. The entries also do not replace the stated primary endpoint result, which is not posted.

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

The record establishes that an open-label, single-group study of 131I-8H9 was registered, with safety and toxicity named as its primary outcome and tumor detection described as its purpose. It includes a limited set of adverse-event counts and percentages. These are descriptive observations recorded for the study group, not comparative estimates.

The record does not report the primary endpoint result, despite describing the measure as the total number of participants affected over 2 years. It also does not report a statistical analysis of tumor-detection performance. The posted information therefore cannot quantify how often participants were affected under the primary outcome definition, how precisely that measure was estimated, or how well tumors were detected.

Because no concurrent control is described, differences attributable to the intervention cannot be separated from other explanations using this record alone. The study is not randomized, is open-label, and has no listed like-for-like control comparison. This does not make the descriptive observations meaningless, but it limits the kinds of conclusions they can support.

The serious-event and other-event entries should be interpreted according to their individual labels. Their denominators and relationship to the enrollment entry are not explained. The percentages do not establish causation, and missing information about follow-up, event definitions, and analysis populations further constrains interpretation.

The registry lists the study as terminated. The reason is not reported in the registry record, so termination cannot be interpreted as a safety finding, a failure of tumor detection, or evidence of any other outcome. Overall, the posted data provide some safety descriptions but not a complete primary-outcome analysis or an answer about diagnostic performance.

14. Why This Trial Matters Statistically

This study illustrates why a registry’s stated objective and its posted results must be distinguished. The stated purpose concerns finding tumors, while the designated primary outcome concerns safety and toxicity. Neither the primary safety result nor a tumor-detection analysis is reported. A reader therefore cannot treat the stated purpose as evidence that detection performance was demonstrated or evaluated successfully.

It also shows the limits of interpreting event counts without clear outcome definitions and analysis details. The record provides category-specific affected counts and percentages, but does not explain their denominators, their relation to enrollment, or how they map to the primary endpoint. Such information is important for judging both the meaning and the precision of safety data.

The single-group design is another key statistical feature. Observed outcomes in a treated group can describe what happened during the study, but they do not provide a direct controlled contrast. The record explicitly warns that the arms are not a like-for-like control comparison. Statistical significance or an intervention effect cannot be inferred from descriptive event entries alone.

Finally, the record demonstrates why missing analysis details matter. It does not report an analysis population, missing-data procedures, multiplicity plan, or sample-size justification. Planning illustrations described in the record are not a substitute for the study’s own design rationale and are not observed power. These distinctions help prevent numerical safety listings from being mistaken for a complete account of trial evidence.

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 limitations specific to this record begin with the absence of a posted primary-outcome analysis. Although the endpoint is defined as a total number of participants affected over 2 years, the registry does not report the result, an uncertainty interval, or a statistical test. The stated tumor-detection purpose is also not accompanied by a reported detection outcome or accuracy analysis.

The study is open-label and single-group, with allocation listed as NA. There is no concurrent comparator described, and the registry warns that arms are not a like-for-like control comparison. This limits causal interpretation and prevents direct comparison of the posted event counts with an alternative approach.

There are gaps in the safety reporting context. The registry lists 12 for enrollment but shows 5 at risk for each adverse-event category, without explaining the relationship. The denominator for the serious-event term percentages is not specified in the record, and the terms may not represent mutually exclusive participants. Deaths are not reported in the registry record. Event timing, severity grading, duration, and attribution methods are also not reported.

Follow-up completion and handling of missing data are not reported, even though the primary outcome timeframe is 2 years. The analysis population, detailed outcome definitions, statistical plan, interim analyses, and study-specific sample-size justification are not reported in the registry record. The reason for termination is not reported either. These gaps restrict interpretation of both the safety entries and the study’s ability to address its stated tumor-detection objective.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Tumor Detection Using Iodine-131-Labeled Monoclonal Antibody 8H9 — NCT00582608.
• Registry record last updated 2017-03-01; status last verified 2017-01.
• Results first posted 2017-03-01.
• 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

NCT00582608 is a Memorial Sloan Kettering Cancer Center study titled Tumor Detection Using Iodine-131-Labeled Monoclonal Antibody 8H9. The registry describes an open-label, single-group study of intravenous 131I-8H9, preceded by unlabeled 8H9. Phase is listed as NA, enrollment as 12, and status as terminated. The recorded start is 2001-10 and primary completion is 2009-05.

The stated primary outcome is the total number of participants affected by safety or toxicity over 2 years. The registry lists one outcome measure and 0 analyses; no primary result is posted. Adverse-event entries include category-specific participant counts and serious-event term percentages, but the record does not clarify all denominators or their relationship to enrollment. A tumor-detection analysis, comparator, analysis population, missing-data method, and study-specific statistical plan are not reported in the registry record.