Safety of Stool Transplant for Patients With Difficult to Treat C. Difficile Infection: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety of Stool Transplant for Patients With Difficult to Treat C. Difficile Infection (NCT02770326), a na na study. The primary outcome is Number of Participants Evaluated for Infection During Treatment Intervention.

2. Clinical Question

The clinical question is framed around safety in a population that the registry describes as having cancer and difficult-to-treat C. difficile infection. Its stated aim is to assess FMT in patients with recurrent or refractory infection and solid tumors. This is not a trial designed to estimate a treatment contrast: the registry reports no random assignment and no control arm. The study can therefore be understood as a single-group safety investigation, not as a direct comparison of FMT with another approach. The registry record does not report a comparative efficacy question or an efficacy result.

3. Trial Design

The registry describes a completed, single-group, open-label study sponsored by Memorial Sloan Kettering Cancer Center. The phase is listed as NA, allocation as NA, and masking as NONE. Enrollment is recorded as 10. The study start is 2016-05-10, and primary completion is recorded as 2024-02-16. These registration details describe the design and timeline; they do not establish what analyses were performed or whether every enrolled participant contributed to every outcome.

Participants with recurrent or refractory C. difficile infection who met eligibility criteria were to undergo FMT by colonoscopy or upper endoscopy, with infusion of stool admixture. The record does not report how the route was selected, how many participants underwent each procedure, or any additional treatment details beyond that description. The primary safety monitoring period is 2 weeks after the FMT procedure.

Because there is no concurrent control arm, the design does not support a randomized between-group treatment comparison. Outcomes observed after FMT can be described for the study group, but any change from a prior condition or comparison with usual care is not established by this design. The record does not report a protocol-level sample-size justification, interim analyses, or a statistical analysis plan. Although planning illustrations use assumptions for a hypothetical equal-allocation, two-arm design, those assumptions are not the registered trial design and should not be read as observed power or as evidence of a planned comparison.

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 Number of Participants Evaluated for Infection During Treatment Intervention, measured over 2 weeks after the FMT.

The primary outcome is titled “Number of Participants Evaluated for Infection During Treatment Intervention.” Its unit is participants, and the description says safety is assessed by monitoring two types of infections occurring within 2 weeks of the FMT procedure. In practical terms, the endpoint concerns participant counts associated with infection monitoring over the stated post-procedure period, rather than a continuous measurement such as a laboratory value.

Safety outcomes of this kind are used to make potential harms visible in the population receiving an intervention. A count can describe how many participants met an event definition, but its interpretation depends on clear definitions, complete follow-up, and a known analysis population. The registry record does not name the two infection types, specify the detailed event definitions, or report a numerical primary-outcome result. It also does not report whether the outcome counts participants with any infection, separate infection categories, or another prespecified rule for counting. Those details should not be inferred from the title alone.

The stated timeframe is 2 weeks after FMT. That makes the outcome a focused short-term safety measure; it does not establish that later infections were assessed or absent. No statistical estimate, confidence interval, or analysis result for this endpoint is reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered study is single-group and open-label, with allocation listed as NA and masking as NONE. These design labels matter because they determine what kinds of statistical conclusions are supported. A single-group study can describe outcomes among participants who receive the intervention. Without a concurrent comparator, it cannot estimate a randomized difference between intervention and control groups. Open-label status means the registry does not describe masking; the record does not give further details about how outcome assessments were conducted.

What does a participant count tell us?

General statistical explanation: a count endpoint records how many participants meet a specified event definition. It is different from an event rate over person-time, a time-to-event result, or a continuous outcome. For a count to be interpretable, readers need to know the event definition, the population included in the denominator, the observation period, and how missing assessments were handled. In this study, the primary outcome description identifies infection monitoring within 2 weeks after FMT, but the infection types and numerical outcome result are not reported in the registry record.

A count alone also does not convey precision. General statistical explanation: uncertainty around an event count depends on the number of participants observed and on the number who experience the event. A confidence interval expresses a range of values compatible with the observed data under the chosen statistical method. No confidence interval or primary-outcome analysis is reported in the registry record, so no such precision estimate can be interpreted for the endpoint.

Why does the absence of a comparator matter?

General statistical explanation: randomization helps balance measured and unmeasured factors, on average, between comparison groups. Here, the design is recorded as a single group, with allocation NA. The resulting outcomes can be described for the FMT group, but there is no randomized contrast from which to estimate a treatment effect. Comparing the study outcomes with external experience would require additional data and assumptions that are not reported in the registry record.

The registry reports one primary outcome measure and no analysis records. It does not report a test statistic, p-value, effect estimate, confidence interval, or model specification for the primary endpoint. Consequently, statistical significance cannot be assessed from the primary-outcome entry. The absence of an analysis record is not evidence that an analysis did or did not occur outside the information recorded in the registry.

How should planning illustrations be read?

General statistical explanation: sample-size planning calculations describe how much information a hypothetical design might require under specified assumptions. They are not a measure of the probability that a completed study has detected an effect. The planning illustration associated with this record assumes a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. Those assumptions do not match the registered single-group design. The illustrations are planning scenarios, not observed power and not a reconstruction of the study's original design rationale.

The illustration instructions distinguish time-to-event calculations, which express a total number of events, from other calculations, which express participants per arm. General statistical explanation: that distinction reflects the information used by different statistical methods. Event-driven time-to-event designs depend on event counts, whereas many comparisons of other outcome types are planned around group sizes. Neither format supplies missing trial results or makes a single-group study comparative.

What can be concluded about model choice?

The endpoint is a participant count and is identified as binary in the registry data. General statistical explanation: binary outcomes distinguish whether a participant meets an event definition; summaries may report event counts and denominators, while models may estimate probabilities or contrasts. Over-dispersion is a concern when observed variability exceeds what a chosen probability model expects, and can make standard errors too small if ignored. The registry record does not report a model, an over-dispersion assessment, or a model-based estimate. No particular method should therefore be attributed to this study based on the available record.

Recalculated comparisons are not applicable to the primary endpoint because no primary-outcome summary statistics or comparative groups are reported. The sponsor's analysis cannot be contrasted with a recalculation using the information in the registry record. In general, recalculation from summary statistics would be unadjusted and would not supersede a sponsor's own analysis if a discrepancy were reported; no such discrepancy is reported in the registry record.

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("Fecal Microbiota Transplantation (FMT)")
n      <- c(10)
events <- c(10)
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  Fecal Microbiota Transplantation (FMT)  10  10  100.0  69.2  100.0  72.2  100.0  71.5  99.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome measure and no analysis records. It does not report a statistical analysis plan, a hierarchy of outcomes, a multiplicity adjustment, or the number of hypotheses tested. The absence of those details means the handling of multiple comparisons is not reported in the registry record; it should not be assumed that no additional analyses were performed or that any particular correction was used.

General statistical explanation: multiplicity arises when several outcomes, time points, subgroups, or statistical tests are examined. Testing multiple hypotheses can increase the chance of a false-positive finding if each test is treated as though it were the only test. Prespecified priorities and adjustment procedures can help readers understand how confirmatory claims are controlled. The registry information does not describe such procedures for this study.

Missing-data handling is also not reported in the registry record. No outcome-specific denominator, participant flow, number of missing assessments, reason for missingness, or imputation method is posted in the recorded outcome information. The enrollment figure alone cannot establish how many participants contributed data to the primary endpoint or whether follow-up was complete.

The analysis population is not defined in the registry record. It is therefore unclear whether the primary outcome was intended to include all enrolled participants, only those who underwent FMT, or another population defined by eligibility or follow-up. These distinctions matter because counts and uncertainty depend on which participants are included. No assumptions about exclusions, treatment adherence, or missing outcomes should be added to the registry entries.

12. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event entry for the FMT group reports 10 participants at risk and 0 affected for serious adverse events. It reports 10 at risk and 10 affected for other adverse events, and reports 7 deaths. These are separate registry fields and should be read as recorded rather than combined into a single summary. The entry does not provide serious adverse-event terms.

The record does not report the timing, causes, or relationship to FMT for the deaths. It also does not explain how the serious and other event categories were defined, whether categories could overlap, or how the at-risk populations were determined. The primary endpoint focuses on infection within 2 weeks after FMT, but the adverse-event death figure should not be assumed to refer to that same period.

General statistical explanation: adverse-event counts describe events recorded in a defined group; by themselves, they do not establish causation. Assessing causality requires clinical and temporal information and, often, a suitable comparison. The single-group design does not provide a randomized comparator for that assessment. The figures should therefore be treated as descriptive reports, not as proof that FMT caused or prevented any event.

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

The registry record establishes that the study was designed to examine FMT safety in patients with recurrent or refractory C. difficile infection and solid tumors. It also documents a short-term infection-monitoring timeframe, an open-label single-group design, and selected adverse-event counts. The primary outcome is relevant to the stated safety question, but its numerical result is not reported in the registry record.

These registry entries do not establish the frequency of the primary infection outcome, its precision, or how that frequency compares with another treatment. The absence of a control group prevents a randomized estimate of comparative effect. The adverse-event entries also cannot establish that FMT caused the recorded deaths or other events, because the registry record does not report their causes, timing, or relationship to the intervention.

Nor does the record establish that no infections occurred, that all participants completed follow-up, or that later events were assessed. The primary outcome description is limited to infection monitoring within 2 weeks after FMT. The record does not name the infection types or provide a detailed outcome definition, analysis population, or missing-data method.

General statistical explanation: a study result is most informative when an estimate is paired with a measure of uncertainty and a clear account of who was analyzed. Without those elements, readers cannot judge how precisely an observed count reflects the underlying population or how sensitive it may be to missing information. Here, the available registry entries support a limited descriptive account, not a definitive causal or comparative conclusion.

The title and stated purpose identify the clinical motivation, but motivation is not evidence of an outcome. The registry record does not report an efficacy result, and the safety objective should not be interpreted as proof of efficacy or as a treatment recommendation.

14. Why This Trial Matters Statistically

This study addresses a population identified in the registry as having both cancer and difficult-to-treat C. difficile infection. Statistically, that context makes clear outcome definitions and careful accounting of follow-up especially important: a safety count is meaningful only when readers know what qualified as an event, who was observed, and over what period.

The record also illustrates the distinction between a safety question and a comparative treatment question. Its single-group design can describe recorded outcomes after FMT, but it does not create a randomized counterfactual. An observed event count cannot, by itself, tell readers what would have happened to comparable participants without the intervention or with an alternative approach.

The registry includes a defined short-term monitoring window and adverse-event counts, yet does not report a numerical primary infection result or its analysis. This gap illustrates why registration details and posted outcome analyses serve different purposes. A trial may have a clear objective and a named endpoint, while the registry record still lacks information needed to quantify that endpoint or its uncertainty.

Finally, the planning illustrations use assumptions for a two-arm comparison, while the registered trial is single-group. Recognizing that mismatch prevents a planning calculation from being mistaken for evidence about the completed study. Sound interpretation depends not only on numbers, but also on whether the assumptions behind those numbers match the design and question.

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 primary limitation for interpretation is that the registry record does not report a numerical result for the primary infection outcome, although it describes the endpoint and its 2-week timeframe. The two infection types are not named, and detailed event definitions are not reported. No confidence interval or primary-outcome analysis is available in the registry record.

The single-group design has no concurrent control, and the record lists allocation as NA and masking as NONE. It therefore cannot provide a randomized comparison. The record does not report how participants were selected for colonoscopy versus upper endoscopy, whether procedure route influenced outcomes, or whether the intervention was delivered uniformly.

Enrollment is recorded as 10, but outcome-specific denominators, participant flow, missing assessments, analysis-population definitions, and follow-up completeness are not reported. The safety entries include deaths, but their causes, timing, and relationship to FMT are not given. Serious adverse-event terms are also not listed.

The registry record does not report a statistical analysis plan, sample-size justification, interim analyses, missing-data procedures, or multiplicity handling. The planning assumptions describe a hypothetical two-arm framework and do not resolve these trial-specific gaps. These limitations mean the available information supports only a cautious descriptive reading of the registered design and adverse-event fields.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Safety of Stool Transplant for Patients With Difficult to Treat C. Difficile Infection — NCT02770326.
• Registry record last updated 2025-04-08; status last verified 2024-02.
• Results first posted 2025-04-08.
• 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

NCT02770326 is a completed, open-label, single-group study sponsored by Memorial Sloan Kettering Cancer Center. It enrolled 10 participants and examined FMT for recurrent or refractory C. difficile infection in patients with solid tumors. FMT was delivered by colonoscopy or upper endoscopy with infusion of stool admixture. The primary safety outcome concerned participant infection monitoring during the 2 weeks after FMT.

The registry reports no primary-outcome analysis. In the FMT group, serious adverse-event fields report 0 affected among 10 at risk, other adverse-event fields report 10 affected among 10 at risk, and deaths are reported as 7. Causes and relationships to FMT are not reported in the registry record. The single-group design does not support a randomized treatment comparison.