Myeloablative Umbilical Cord Blood Transplantation in Hematological Diseases: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Myeloablative Umbilical Cord Blood Transplantation in Hematological Diseases (NCT00309842), a na phase 2 study. The primary outcome is Number of Participants Who Were Alive at 1 Year Transplant Overall Survival.

2. Clinical Question

In statistical terms, the study describes outcomes following a particular transplant approach in the enrolled clinical setting. It does not estimate a randomized treatment effect against an alternative regimen. Eligibility details, baseline disease composition, and other factors that would help characterize who contributed to the primary endpoint are not reported in the registry record.

3. Trial Design

This is a phase II clinical trial with a single-group model. The registry records enrollment of 213 and status as completed. The study start is 2005-07-28, and primary completion is recorded as 2019-07-29. Allocation is listed as not applicable, and masking is none. These design features describe a study without randomized assignment or masking between treatment groups; the registry does not identify a concurrent control group.

The study group is described as patients undergoing unrelated umbilical cord blood transplantation for hematologic malignancies. Its preparative regimen includes fludarabine phosphate, cyclophosphamide, and fractionated total-body irradiation. The arm description also names mycophenolate mofetil, filgrastim, and cyclosporine. The registry lists these treatments and procedures but does not report further details about dose, schedule, treatment modifications, adherence, or supportive care. Such details are not reported in the registry record.

The primary outcome is the number of participants alive at 1 year after transplant. Secondary outcomes cover transplant-related death, platelet and neutrophil engraftment, acute and chronic graft-versus-host disease, and chimerism at specified follow-up times. The registry lists 11 outcome measures, but does not provide analysis results for the primary endpoint in the available record. It also lists zero analyses. The analysis populations, follow-up completeness, and approach to censoring are not reported in the registry record.

Because there is one group, outcomes can describe what happened among participants assessed under this regimen, if those results are reported. They cannot by themselves distinguish the regimen's contribution from the influence of disease characteristics, transplant context, or other factors. No statistical analysis plan, sample-size justification, or interim analysis information is 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 Number of Participants Who Were Alive at 1 Year Transplant Overall Survival, measured over at 1 year.

The primary endpoint is the number of participants who were alive at 1 year after transplant. The registry describes it as a count of patients alive at that follow-up time and labels it transplant overall survival. It is a clinically interpretable status at a defined time point: the outcome indicates how many participants in the analyzed population met the stated condition at that time.

In general, survival outcomes are used to summarize whether participants remain alive over follow-up. A fixed-time count is straightforward to communicate, but its interpretation depends on knowing which participants were included, how survival status was determined, and whether follow-up was complete. A count alone does not show the uncertainty around the estimate or describe the timing of deaths during follow-up. A time-to-event analysis can use the timing of events and account for censoring, but the registry record does not report such an analysis for this primary outcome.

The registry lists the timeframe as at 1 year, but does not report the primary endpoint count, the denominator used for analysis, or an estimate of uncertainty. These details are not reported in the registry record. Enrollment of 213 is not interchangeable with the number included in the endpoint analysis. The endpoint therefore identifies the question being asked, but the recorded information does not establish its numerical answer or its precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design and the outcome definition determine which statistical interpretations are possible. The registry describes a phase II, single-group study with no masking and allocation recorded as not applicable. The primary endpoint is a count of participants alive at 1 year after transplant. No primary endpoint estimate or analysis method is reported in the registry record, so the methods discussion must distinguish general statistical principles from analyses actually documented for this study.

What does a single-group design estimate?

A single-group study can describe outcomes among participants receiving the study regimen. For a binary status such as alive or not alive at a specified time, a count can be paired with a denominator to estimate the observed proportion in the analyzed group. The registry reports enrollment of 213, but does not report the primary analysis denominator or the number alive at 1 year. It is therefore not possible to state an observed proportion from the record. A single-group result also does not quantify a difference from an alternative treatment.

General statistical explanation: a confidence interval expresses the uncertainty associated with an estimate under a statistical model. It communicates a range of values compatible with the data and assumptions, rather than guaranteeing that a particular value is correct. No confidence interval for the primary endpoint is reported in the registry record. Without the count, denominator, and uncertainty estimate, the precision of the primary endpoint cannot be assessed.

Why does the outcome's time definition matter?

A status recorded at 1 year is a fixed-time outcome. It gives a snapshot at the stated follow-up point, but does not by itself describe when events occurred or how follow-up differed among participants. General statistical explanation: time-to-event methods use event timing and can account for participants whose event status is not observed through the same duration, using censoring rules. Such methods require definitions of the event, follow-up, and censoring. The registry record does not report whether a time-to-event method was used for the primary outcome, or how censoring and incomplete follow-up were handled.

A count also needs a clearly defined denominator. The enrollment number describes registry enrollment; it does not prove that every enrolled participant was eligible for, or included in, a particular endpoint analysis. The analysis population and endpoint-specific denominator are not reported in the registry record. General statistical explanation: if some participants lack outcome information, excluding them, classifying them, or using a model to address missingness can lead to different estimates. The approach matters, particularly when missingness is related to prognosis or treatment experience.

What can adverse-event summaries establish?

The safety information lists participants at risk and affected for serious adverse events and other adverse events. General statistical explanation: event counts and the number of participants affected are different summaries. A participant can experience more than one event, and a participant-level affected count does not convey the total number of events. The registry does not report event-level detail, follow-up duration for these summaries, or whether people could contribute to more than one term. Percentages attached to serious-event terms should not be treated as rates unless their denominator and calculation are clear; those details are not reported in the registry record.

Over-dispersion is a general concern when modeling counts of events. It occurs when observed variability exceeds what a simple count model assumes, for example when event counts vary substantially across participants. In that setting, a model that assumes less variability can produce uncertainty estimates that are too small. This concept does not establish that over-dispersion occurred in this trial: the primary outcome is a participant count, and the registry record does not report a count-model analysis.

What analysis choices are documented?

The record lists 11 outcome measures and zero analyses. It does not report a statistical analysis plan, hypothesis tests, adjustment covariates, confidence intervals, interim analyses, or a sample-size justification. Those choices should not be inferred from the phase designation or the outcome list. The record's sample-size assumptions describe planning illustrations based on an observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These are planning assumptions, not a report of the study's design rationale or observed power. Since the trial is single-group, illustrations assuming two arms do not describe the trial's allocation.

In general, statistical methods should match the endpoint and design. A binary endpoint can be reported with its count, denominator, and an interval estimate, while a time-to-event endpoint may call for methods that account for event timing and censoring. The registry record does not report which inferential methods, if any, were used for the primary endpoint. Readers therefore can identify the intended outcome and study structure, but cannot evaluate the analysis implementation or reproduce an estimate from the 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("Unrelated UCBT for Blood Cancers")
n      <- c(212)
events <- c(130)
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  Unrelated UCBT for Blood Cancers  212  130  61.3  54.4  67.9  54.6  67.6  54.6  67.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 11 outcome measures, including the primary survival endpoint and secondary outcomes for transplant-related death, engraftment, graft-versus-host disease, and chimerism. When a study examines several outcomes, there are multiple opportunities to observe results that appear notable by chance. General statistical explanation: multiplicity procedures can control the chance of false-positive findings across a defined family of tests, while prespecified outcome hierarchy can clarify which questions are primary. The registry record does not report a multiplicity strategy, a testing hierarchy beyond naming the primary outcome, or the results of hypothesis tests.

The registry lists zero analyses. A formal analysis population, endpoint-specific denominators, and handling of participants with missing outcomes are not reported in the registry record. These omissions matter because the enrollment count cannot substitute for an outcome-specific denominator. General statistical explanation: missing data can affect both the estimate and its uncertainty, and the direction of bias depends in part on why information is missing and how it is handled. No imputation, censoring, or sensitivity-analysis approach is reported in the registry record.

The record also does not report whether any interim analyses were planned or conducted, or how final analyses were selected. These details are not reported in the registry record. Without information about multiplicity, missingness, and analysis populations, the outcome list alone cannot establish how many statistical comparisons were made or how complete the reported results would be. Because no primary result is reported, the magnitude and precision of that endpoint remain unavailable regardless of the approach to multiplicity.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: death (19.3%), graft versus host disease (gvhd) (6.1%), infection (4.7%), graft failure (4.2%), relapse (3.3%).

The safety listing reports a serious-adverse-event group with 212 participants at risk and 92 affected, and an other-adverse-event group with 212 at risk and 187 affected. It also lists 161 deaths. These are the record's reported counts; the relationship among the groups, death count, and primary survival endpoint is not reported in the registry record. In particular, the listing does not establish that the death count refers to deaths by 1 year or that all deaths were attributed to transplant.

The record lists serious-event terms with percentages: Death, 19.3%; graft versus host disease, 6.1%; infection, 4.7%; graft failure, 4.2%; relapse, 3.3%; and acute respiratory distress syndrome, 1.9%. The denominator and calculation method for these percentages are not reported in the registry record. They should therefore be read as registry-listed percentages for the named terms, not converted into event counts or interpreted as comparative risks. The terms may not be mutually exclusive, and the record does not explain their overlap.

General statistical explanation: adverse-event summaries depend on definitions, observation periods, and whether the unit is participants or events. A participant may have multiple event types, and an event listing does not by itself establish causality. The registry information does not report enough detail to determine event timing, recurrence, severity grading beyond the serious classification, or attribution rules. These safety data describe recorded events but do not provide a controlled comparison of safety between regimens.

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

The record identifies the clinical setting, regimen, design, and intended primary outcome. It describes a phase II, single-group study of unrelated umbilical cord blood transplantation for hematologic diseases, with a myeloablative preparative regimen. The primary question concerns the number of participants alive at 1 year after transplant. These details clarify what the trial set out to describe.

The record does not report the numerical primary outcome. Accordingly, it cannot establish from the available information how many participants were alive at the specified follow-up time, what proportion that count would represent, or how precise an estimate would be. Enrollment of 213 is not an endpoint result. The adverse-event counts and listed percentages address safety summaries and do not replace the missing survival result.

Even if a single-group outcome were reported, its interpretation would be descriptive. General statistical explanation: an outcome observed after treatment is not, by itself, an estimate of what would have happened to the same participants under a different treatment. Without a randomized comparator, differences attributable to patient characteristics, disease mix, clinical practice, or other influences cannot be separated from the treatment context through a direct randomized contrast. The registry record does not report a control group.

The result also cannot establish the benefit-risk balance relative to another regimen. The safety listing has no comparative arm and its percentages have no reported denominator in the record. Details on follow-up completeness, event attribution, and analysis population are not reported in the registry record. Those limits prevent a more complete assessment of both efficacy and safety from the listed information.

The appropriate reading is therefore restrained: the registry documents a completed phase II study with a defined primary outcome and reported safety counts, but the primary outcome result and statistical analysis details are absent from the available record. Neither a positive nor a negative conclusion about treatment effects can be drawn from an unreported primary result. The design supports description of the treated group, not a causal comparison with an alternative.

14. Why This Trial Matters Statistically

This trial illustrates how a clearly named endpoint and a defined follow-up time do not, on their own, make a result interpretable. The primary outcome is the number of participants alive at 1 year after transplant, but the registry record does not report that count, an analysis denominator, or an uncertainty estimate. The difference between knowing the question and having the result is central to statistical reading.

The single-group design is also important. Outcomes after unrelated umbilical cord blood transplantation can describe experience in the study group, but do not supply a randomized comparison with another regimen. General statistical explanation: comparative effectiveness questions require a credible basis for estimating what outcomes would have been under the alternative. Randomization is one way to support that comparison; an uncontrolled group does not provide it.

The trial's outcome list also highlights why analysis populations and follow-up definitions matter. Survival, transplant-related death, engraftment, graft-versus-host disease, and chimerism are different outcomes with distinct definitions and denominators. The registry record does not report complete analysis details for these measures. Safety counts and percentages likewise require clear denominators and event definitions to support interpretation.

For biostatisticians and clinical researchers, the record is a reminder to separate design information, endpoint definitions, observed results, and inferential claims. A completed status and substantial enrollment do not substitute for outcome estimates or analysis documentation. Reporting the counts, denominators, uncertainty, missing-data handling, and analysis populations would be necessary to assess the primary result. In their absence, statistical conclusions must remain limited to what the registry explicitly records.

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 main limitation for interpreting this trial from the registry record is that the primary outcome result is not reported. The record names survival at 1 year after transplant but gives no count alive, endpoint denominator, or interval estimate. The enrollment of 213 cannot be assumed to equal the primary analysis population. The amount and pattern of missing follow-up information are not reported in the registry record.

The single-group design has no reported randomized comparator, so it cannot provide a direct treatment contrast. The record does not report a statistical analysis plan, model specification, adjustment strategy, interim analysis information, or sample-size justification. It also does not report whether the primary outcome was analyzed as a fixed-time status or using time-to-event methods, or how censoring was handled. These details are not reported in the registry record.

The listed conditions cover a broad range of hematologic diseases, but the distribution of diagnoses and other baseline characteristics are not reported in the registry record. Eligibility criteria, treatment delivery details, and follow-up completeness are also not reported. Thus, the record does not allow detailed assessment of which participants contributed to each outcome or how representative the analyzed group may be.

The safety listing gives affected counts and percentages for serious-event terms, but the denominator for the term percentages, observation window, event-level details, and attribution methods are not reported in the registry record. The death count should not be equated with the primary survival outcome because the definitions and time frames are not established as identical. These limitations constrain interpretation of both outcome effectiveness and safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Myeloablative Umbilical Cord Blood Transplantation in Hematological Diseases — NCT00309842.
• Registry record last updated 2020-09-10; status last verified 2020-09.
• Results first posted 2020-09-10.
• 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

NCT00309842 is a completed phase II, single-group study of unrelated umbilical cord blood transplantation for hematologic diseases. The registry records enrollment of 213, no masking, and allocation as not applicable. The preparative regimen includes fludarabine phosphate, cyclophosphamide, and fractionated total-body irradiation, with other listed treatments including cyclosporine, mycophenolate mofetil, and filgrastim.

The primary outcome is the number of participants alive at 1 year after transplant. Its result, denominator, and uncertainty estimate are not reported in the registry record. The record lists 11 outcome measures and zero analyses. Safety information includes counts for participants at risk and affected, a death count, and percentages for listed serious-event terms; the percentage denominators and relevant analysis details are not reported.

The design supports descriptive interpretation of a single treated group, not a randomized comparison. Missing outcome results and analysis details limit conclusions about the primary endpoint, its precision, and the handling of follow-up.