T-Cell Depleted Double UCB for Refractory AML: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for T-Cell Depleted Double UCB for Refractory AML (NCT01464359), a na phase 2 study. The primary outcome is Disease Free Survival.

2. Clinical Question

The trial’s stated biological focus is early and later donor-derived NK-cell expansion and function after transplantation. Its brief summary describes the UCB source as presumed to contain NK progenitors requiring education in the recipient. These statements explain the rationale recorded for the platform; they are not outcome findings. The registry record does not report measured NK-cell expansion or function in the results summarized for this analysis.

3. Trial Design

This is a phase 2, single-group study with no masking. The registry lists allocation as NA and enrollment as 3. Its status is TERMINATED. The recorded start is 2011-10, and primary completion is listed as 2013-10. The sponsor is Masonic Cancer Center, University of Minnesota.

The study concerns patients with chemotherapy-refractory AML receiving a double T-cell-depleted UCB transplant. The arm description says the smaller unit is activated overnight in IL-2. The primary endpoint description further specifies two courses of IL-2 administration, three times a week for 6 doses, beginning on day +3 and day +60. The listed interventions also include Allopurinol, Fludarabine, Total body irradiation, Cyclophosphamide, Levetiracetam, Busulfan, Umbilical Cord Blood Transplantation, and Interleukin-2. The registry’s intervention list does not by itself describe the precise regimen or exposure received by each participant.

Because there is no registered control arm, the design is not a like-for-like comparison of treatment groups. Any observed endpoint count would describe outcomes in the enrolled group, not a randomized contrast. The registry record does not report a protocol-level explanation for the termination, a sample-size justification, or details about how participants were followed and analyzed. It also does not report a statistical analysis plan or outcome analyses. Those omissions limit what can be concluded about the design beyond the information explicitly recorded.

The registered primary completion date and terminated status describe the study’s administrative record, not the availability or interpretation of a clinical result. Enrollment of 3 is not necessarily equivalent to the number included in an endpoint analysis; the analysis population is not reported in the registry record. No comparison with historical or external participants is described as part of the trial design recorded.

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

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 Disease Free Survival, measured over At 3 months.

The primary endpoint is Disease Free Survival at 3 months, with the measure expressed as a number of participants. In general, a disease-free survival endpoint is intended to capture whether participants remain free of disease over a defined follow-up period. The registry’s brief endpoint label does not provide a detailed event definition, such as how recurrence, progression, or death would be handled. That operational definition is not reported in the registry record.

A fixed-time endpoint can provide a clinically interpretable snapshot: it asks how many participants meet the stated disease-free criterion by the specified assessment time. It differs from an endpoint that reports the timing of each event over follow-up. General interpretation depends on a clear definition of what counts as an event, complete ascertainment at the target time, and a stated method for handling participants whose status is unknown. Those details are not reported in the registry record.

The endpoint is relevant to the study’s stated population because it concerns disease status after a transplant approach intended for chemotherapy-refractory AML. However, the registry record does not report the number meeting the endpoint, the number assessed at the target time, or a confidence interval. It therefore does not support an estimate of the observed disease-free survival proportion or how precisely that outcome was measured.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What can a single-group study estimate?

In general, a single-group study can describe outcomes among participants who receive the study approach. For a binary endpoint, the basic descriptive quantity is the number meeting the endpoint relative to the number assessed, provided both are reported and the outcome definition is clear. Here, the primary measure is stated as a number of participants, but neither the endpoint count nor the analyzed denominator is reported in the registry record. An endpoint rate therefore cannot be reconstructed.

A treatment effect is different from an outcome count. It compares outcomes under alternative conditions, such as treatment and control. A randomized comparison helps balance prognostic factors across groups, on average, and supports a causal interpretation under the trial’s assumptions. This trial is listed as single-group, with allocation NA and no control arm. There is consequently no within-trial contrast from which to estimate a randomized treatment effect. A historical comparison would require an explicitly defined external group and suitable methods; such a comparison is not reported in the registry record.

What does a confidence interval add?

In general, a confidence interval expresses uncertainty around an estimate. It helps distinguish a precise estimate from one that is compatible with a broad range of underlying outcomes. The interval’s meaning depends on the statistical model and assumptions used to calculate it. For a participant-count endpoint, an interval would ordinarily accompany an estimate based on a defined numerator and denominator. Neither an endpoint estimate nor its interval is reported. Consequently, no precision claim about disease-free survival at 3 months can be made.

A small enrolled group generally yields limited information about uncommon outcomes and can produce substantial uncertainty. This is a general statistical point, not an estimate of uncertainty calculated for this trial. The registry record reports enrollment of 3, but it does not provide the endpoint data needed to quantify the uncertainty. It would be inappropriate to infer a confidence interval or a likely range of outcomes from enrollment alone.

How should the trial’s design shape interpretation?

The study is identified as PHASE2, single-group, and unmasked. In general, phase 2 studies can be used to characterize activity, safety, and feasibility, but the label alone does not specify a particular design or analysis. The registry record does not report the study’s statistical plan, decision criteria, sample-size justification, or any interim analysis. Those features should not be inferred from the phase designation.

Without masking, knowledge of treatment can potentially influence outcome assessment or reporting, depending on the endpoint and procedures. For a clearly defined objective outcome, the implications may differ from those for an outcome requiring judgment. The registry record does not describe endpoint adjudication or blinding of assessors, so the possibility and extent of assessment influence cannot be evaluated. More generally, lack of a comparison group means observed outcomes can reflect the treatment approach, the underlying illness, supportive care, participant selection, and other factors. The study design cannot separate these explanations.

What do the planning assumptions mean?

In general, a sample-size planning illustration asks how many participants a hypothetical design might need to detect a specified effect under stated assumptions. Such a calculation is not a report of what happened in a trial, and it is not “observed power.” The stated planning assumptions for this record describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the intended effect is a stated fraction of the observed effect. The assumptions also distinguish participant-per-arm calculations from total-event calculations for time-to-event settings.

Those assumptions describe a hypothetical two-arm planning exercise, whereas the registered study is single-group. The registry record does not report an observed primary endpoint effect or any analysis results from which a planning effect could be evaluated. No sample-size illustration can therefore be interpreted as a trial finding or as evidence of the precision of this study. Planning illustrations are conditional on their assumptions and should not be confused with the number enrolled, an observed outcome, or a prospectively justified design target.

Why do event definitions and follow-up matter?

For any endpoint, interpretation relies on a prespecified definition, a consistent assessment window, and transparent handling of missing information. At a fixed follow-up time, participants may have different amounts of observation or may lack an assessment. In general, excluding participants with unknown status can bias an estimate if missingness is related to outcome. Other methods can make different assumptions, and those assumptions should be reported. The registry record does not describe missing-data handling, follow-up completeness, or the operational definition of disease-free survival.

These limitations are especially important when the endpoint is expressed as a participant count. A count without its analysis denominator does not establish the proportion meeting the endpoint. A denominator without a clear event definition may also be difficult to interpret. Since neither the endpoint count nor analysis details are recorded in the results available, no further endpoint calculation is justified.

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("Patients With Acute Myelogenous Leukemia")
n      <- c(3)
events <- c(1)
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  Patients With Acute Myelogenous Leukemia  3  1  33.3  0.8  90.6  6.1  79.2  6.8  80.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary endpoint, Disease Free Survival at 3 months, and several secondary outcomes, including graft failure, acute graft-versus-host disease, transplant-related mortality, clinical disease response, and duration of survival. Some secondary outcome labels appear more than once in the registry list. The record does not explain whether these repetitions represent distinct assessment times, analysis definitions, or duplicate entries, so they should not be interpreted as separate findings.

When a study evaluates multiple outcomes, the chance of observing at least one apparently notable result can increase if no multiplicity strategy is used. In general, researchers may identify a primary outcome in advance, adjust tests, or describe secondary findings as exploratory. The registry record does not report a multiplicity plan, hypothesis-testing hierarchy, or analysis results. It is therefore not possible to assess whether any adjustment was intended or how secondary outcomes were meant to support conclusions.

Missing-data methods and analysis populations are also not reported in the registry record. It does not state how participants with unavailable endpoint assessments were handled, whether all enrolled participants were included in the primary analysis, or how follow-up losses were addressed. These details matter because an endpoint count may depend on who was assessed and on the assumptions used for unknown outcomes. Enrollment of 3 does not establish the denominator used for any analysis.

The record lists 0 analyses. Accordingly, there are no reported statistical results from which to assess outcome-specific missingness, multiplicity, or the relationship between the registered outcomes and analyzed populations.

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: infections and infestations - other, blood culture w/gram positive cocci and cmv (33.3%), fever (33.3%), hepatobilliary disorders - other, veno occlusive disease (33.3%).

The registry’s safety summary lists serious adverse events for the group titled Patients With Acute Myelogenous Leukemia. It reports 3 participants at risk and 2 affected for serious events. For other adverse events, it reports 3 at risk and 3 affected. These are participant counts in the registry record; they are not a comparison between treatment groups and do not establish whether the intervention caused an event.

The listed serious-event terms include “Infections and infestations - Other, blood culture w/gram positive cocci and CMV,” “fever,” and “hepatobilliary disorders - Other, veno occlusive disease.” Each is listed with 33.3%. The registry record does not provide accompanying event counts for these terms in the information summarized, so the percentages should be read as reported rather than reverse-engineered into counts. It also does not describe the criteria used to classify events, their timing, duration, severity grades, or relationship to treatment.

The death count is not reported in the registry record. That is different from a report of no deaths. Safety interpretation is further limited by the absence of a control group, the small recorded enrollment, and the lack of detailed follow-up and analysis information. The listed counts describe what the registry records; they do not quantify comparative risk.

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

The record establishes that a phase 2, single-group study was registered for chemotherapy-refractory AML, with double T-cell-depleted UCB transplantation and IL-2 as the central approach. It lists disease-free survival at 3 months as the primary endpoint and describes a biological rationale focused on donor-derived NK-cell expansion and function. The study is marked TERMINATED, with enrollment of 3.

What the record does not establish is the observed disease-free survival outcome. No primary endpoint count, denominator for endpoint analysis, confidence interval, or statistical test is reported. The registry therefore cannot show how many participants were disease-free at the target time or how precisely that outcome was estimated. The absence of a reported result is not evidence that the endpoint was met or not met.

The design also limits comparative conclusions. A single-group study does not provide a randomized control group, so it cannot isolate the effect of the transplant and IL-2 approach from the course of the disease, other care, or participant characteristics. It cannot establish that the approach improved or worsened outcomes relative to an alternative. This remains true even when the study has a biologically motivated intervention and a clinically relevant endpoint.

The safety counts are descriptive. They record participants affected by serious and other adverse events, but do not establish comparative safety or treatment causation. The registry does not report deaths, detailed event definitions, or enough follow-up and analysis information to support a broader safety estimate.

Thus, the defensible conclusion is about the scope and limits of the available record: the trial was designed to study a transplant and IL-2 strategy in refractory AML, but no statistical outcome analyses are listed. Claims about efficacy, lack of efficacy, or comparative safety would go beyond what the registry record reports.

14. Why This Trial Matters Statistically

This trial is statistically notable because its biological rationale and primary endpoint address different levels of evidence. The stated rationale concerns donor-derived NK-cell expansion and function after UCB transplantation. The primary endpoint, however, is disease-free survival at 3 months. In general, biological measures can help investigate a mechanism, while a clinical endpoint describes a participant outcome. Neither type of result substitutes automatically for the other, and the registry record does not report analyses of either.

The single-group structure also makes the distinction between description and causal comparison especially important. A group’s outcome can be clinically informative, but without a comparator it cannot show what would have happened to similar participants under another approach. This is a core design issue rather than a matter that can be resolved by a more elaborate calculation on the same single-group results.

Enrollment of 3 emphasizes why transparent reporting of the outcome numerator, analysis denominator, follow-up, and uncertainty would matter. A participant count alone cannot communicate the endpoint result or its precision. The missing primary endpoint result means readers cannot assess the clinical outcome, while the absence of a reported analysis plan prevents evaluation of how the endpoint was intended to be analyzed.

Finally, the record illustrates why registry status, outcome reporting, and statistical evidence should be kept distinct. TERMINATED describes the recorded study status, but does not explain the reason for termination. The listed adverse events are safety observations, not comparative risk estimates. These distinctions help prevent the design rationale, administrative status, and safety counts from being mistaken for evidence about treatment effect.

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 most consequential limitation for statistical interpretation is that the registry record lists no analyses and does not report the primary endpoint result. Disease-free survival at 3 months is specified, but the event definition, observed count, analysis denominator, and uncertainty estimate are not reported. The analysis population and completeness of follow-up are also not reported in the registry record.

The single-group design has no registered control arm. It therefore cannot provide a randomized treatment contrast or distinguish the intervention’s contribution from other influences on outcome. The record does not describe an external comparator. Allocation is listed as NA, and masking is listed as NONE; assessor procedures and endpoint adjudication are not reported.

Enrollment is listed as 3, and the study status is TERMINATED. The reason for termination, the number completing follow-up, and the relationship between enrollment and analysis are not reported in the registry record. The registry also does not provide a sample-size justification, interim-analysis information, or a statistical analysis plan. These omissions prevent evaluation of whether the study’s design and analyses matched its intended objectives.

Safety interpretation is limited by the absence of a control group and by missing details about event definitions, timing, severity, causality assessment, and follow-up. Deaths are not reported in the registry record. The listed percentages for serious-event terms should not be converted into unreported counts. Overall, the available information supports a description of the registered design and reported safety counts, but not a conclusion about efficacy, comparative safety, or the precision of the primary outcome.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: T-Cell Depleted Double UCB for Refractory AML — NCT01464359.
• Registry record last updated 2017-12-28; status last verified 2017-12.
• Results first posted 2015-05-15.
• 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

The registry record describes a phase 2, single-group study of double T-cell-depleted UCB transplantation with IL-2 for chemotherapy-refractory AML. The primary endpoint is Disease Free Survival at 3 months, measured as a number of participants. The study is listed as TERMINATED, with enrollment of 3 and masking NONE. Allocation is NA.

The primary endpoint result and statistical analyses are not reported in the registry record. The record lists serious adverse events affecting 2 participants among 3 at risk and other adverse events affecting 3 among 3 at risk; deaths are not reported. The single-group design does not support a randomized comparison, and the absence of endpoint results prevents assessment of the primary clinical outcome.