Busulfan and Cyclophosphamide Followed By ALLO BMT: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Busulfan and Cyclophosphamide Followed By ALLO BMT (NCT01685411), a na na study. The primary outcome is Counts of Participants With Disease Free Survival.

2. Clinical Question

The clinical question is descriptive rather than a comparative estimate of treatment effect. The stated primary outcome is a count of participants, not a reported comparison between treatments. The registry record does not report a primary outcome result or an analysis for that endpoint. It therefore does not establish the number of participants meeting the endpoint, nor does it provide an estimate of the probability or duration of disease-free survival.

The brief summary characterizes the record as a treatment guideline intended to collect and maintain routine clinical data in Oncore and the University of Minnesota Blood and Marrow Database as part of a departmental historical database. That context matters: the record describes care and data collection in one group, rather than a trial with a separate control arm. It does not report a formal causal comparison, and the listed information is not enough to determine how the treatment regimen relates to outcomes relative to another regimen or to no treatment.

3. Trial Design

The registry describes a single-group study with no masking. Allocation is recorded as NA, and the phase is also recorded as NA. Enrollment is listed as 5. The status is TERMINATED. The registry record gives a start of 2013-01 and a primary completion date of 2020-02-10; it does not state why the study was terminated.

The listed group is Allogeneic Hematopoietic Stem Cell Transplant. Its description includes Allopurinol, Keppra, Busulfan, Cyclophosphamide, Filgrastim, antithymocyte globulin, Tacrolimus and Mycophenolate mofetil, followed by allogeneic hematopoietic stem cell transplant infusion. The intervention list separately names these medications and the transplant, although antithymocyte globulin appears in the arm description rather than that list. No treatment schedule, dose, or duration is reported in the registry record.

The record lists Acute Lymphoblastic Leukemia, Acute Myeloid Leukemia and Myelodysplastic Syndrome as conditions. It does not provide further eligibility criteria or describe how participants were selected. With no separate comparator group, the design cannot directly estimate a difference between this regimen and another treatment. The absence of masking is recorded, but the registry record does not explain how outcome assessment was organized or whether any safeguards against assessment bias were used.

The brief summary describes the study as a treatment guideline for routine clinical data collection and maintenance in institutional databases. This is useful context for interpreting the record: the listed purpose concerns clinical data capture and a historical database, while the primary outcome is a count of participants with disease-free survival. The registry record does not give a protocol rationale, sample-size justification, or further description of the intended statistical design. Those details should not be inferred from the outcome listing or the enrollment figure.

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 Counts of Participants With Disease Free Survival, measured over 2 Years.

The primary outcome is titled “Counts of Participants With Disease Free Survival,” with Participants as the unit and a timeframe of 2 Years. The description defines disease-free survival as the length of time after treatment ends that a patient survives without signs or symptoms of that cancer or any other type of cancer. It also describes assessments for patients with leukemia involving the bone marrow and myelodysplastic syndrome, including bone marrow biopsy and additional studies as appropriate, and imaging or other studies when clinically indicated.

Disease-free survival is used to describe survival without evidence of disease after treatment. In general, it can capture both whether a participant remains alive and whether disease has returned or is present, rather than describing survival alone. The endpoint title in this record specifies a count of participants, however; it is not itself a reported time-to-event estimate, a rate, or a comparison with another group.

The registry record does not report the count of participants meeting this endpoint. It also does not give a definition of the analysis population, rules for incomplete follow-up, censoring, or the precise way the 2 Years assessment was converted into the stated count. Without those details and an outcome result, the endpoint description explains what the study intended to assess but does not show how many participants had disease-free survival.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a single-group model, lists allocation as NA, and reports 0 analyses. These features set the limits for statistical interpretation: the record does not present a randomized comparison, and it does not post an analysis of the primary endpoint. Statistical methods can clarify what such a record can and cannot establish, but they cannot replace outcome results that are not reported.

What does a single-group result estimate?

In general, a single-group count describes how many participants in that group meet a stated outcome definition. It does not directly estimate a treatment difference because there is no separate group to serve as a comparator. A comparison requires outcomes measured in groups whose treatment assignment and follow-up can be contrasted using a specified analysis. Here, the record lists one transplant group and no comparator. Thus, the clinical question remains descriptive rather than a randomized contrast.

The primary outcome is a count of participants with disease-free survival at 2 Years. A count is an absolute tally; it is not automatically a proportion or a probability. To interpret a count as a proportion would require a clearly defined denominator and outcome population. To interpret it as an estimate over time would require details about follow-up and how participants with incomplete observation were handled. Those analysis details are not reported in the registry record.

What does the time-to-event description imply?

In general, time-to-event methods use both the time until an event and information from participants who have not had an event by their last observation. Such methods can account for differing follow-up, often by treating the last known event-free time as censored. They depend on a defined event, time origin, follow-up rules and assumptions about censoring. The endpoint description refers to the length of time after treatment ends that a patient survives without signs or symptoms of cancer, but the primary outcome title is a count. The registry record does not report a time-to-event analysis, a censoring rule, or an estimated disease-free survival curve. It would be inappropriate to treat the endpoint title alone as evidence that such an analysis was performed.

In general, a confidence interval communicates statistical uncertainty around an estimate. It reflects sampling variability under a chosen method and assumptions; it does not account automatically for every source of bias or uncertainty. No confidence interval for disease-free survival is reported. With five enrolled participants, a small number of outcome changes could alter a group summary substantially, but no participant-level data or primary result are available to quantify that sensitivity.

Why do allocation and masking matter?

Random allocation, when used, can make treatment groups more comparable on average and supports a causal interpretation of between-group differences, subject to other design and analysis assumptions. This record lists allocation as NA and describes a single group, so there is no randomized treatment contrast to interpret. Masking is listed as NONE. In general, masking can reduce the influence of treatment knowledge on some assessments or decisions, but the registry record does not describe the outcome-assessment process or any particular bias-control procedures. The listed masking status should not be used to assume how each outcome was collected.

The listed conditions include Acute Lymphoblastic Leukemia, Acute Myeloid Leukemia and Myelodysplastic Syndrome. In general, outcomes and prognosis can vary across participant groups and clinical circumstances. The registry record does not provide condition-specific outcome results or an analysis adjusted for participant characteristics. It is therefore not possible to assess whether results differ across these conditions, or to evaluate any adjusted estimate.

How should planning calculations be read?

In general, power calculations describe the chance that a planned statistical test will detect a particular effect under specified assumptions. A planning illustration is not observed power and does not indicate what the study demonstrated after data collection. The stated assumptions for the planning illustrations are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect expressed as a stated fraction of the observed effect. Time-to-event calculations use a total event count; other calculations use participants per arm. These assumptions describe hypothetical planning comparisons, while the registry record describes a single-group model with enrollment of 5. They should not be mistaken for the actual allocation or analysis of this study. The trial’s own sample-size justification is not reported in the registry record.

Over-dispersion is a general concern when count outcomes vary more than a statistical model assumes; it can make standard errors too small if the extra variability is ignored. The primary outcome is a count of participants, but the record does not report a count model, dispersion estimate, or inferential analysis. No claim about over-dispersion in these data can therefore be made. More broadly, statistical methods should follow the outcome type and design, and their assumptions and uncertainty should be reported alongside results. In this record, those analysis details are not reported, so the appropriate reading is limited to the design and outcome definitions that are listed.

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("Allogeneic Hematopoietic Stem Cell Transplant")
n      <- c(5)
events <- c(3)
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  Allogeneic Hematopoietic Stem Cell Transplant  5  3  60.0  14.7  94.7  23.1  88.2  22.3  88.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 15 outcome measures, including several secondary outcome descriptions, and 0 analyses. It does not report a multiplicity strategy, such as whether any adjustment was planned for testing multiple outcomes. In general, examining multiple outcomes can increase the chance of at least one apparently unusual result when many statistical tests are conducted. Adjustment methods and a prespecified hierarchy can address some of that concern, but no such method is reported. With no posted analyses, there are no reported outcome tests to interpret as statistically significant or not significant.

Missing-data methods are also not reported in the registry record. The record does not specify how incomplete outcome assessments, withdrawal, loss to follow-up, or unavailable measurements were handled. For a disease-free survival assessment at 2 Years, follow-up and event-status rules are important because a participant without a documented assessment may not have a known outcome at that time. The endpoint description does not, by itself, establish how such cases were classified.

The analysis population is not reported in the registry record. It is not stated whether an analysis would include all enrolled participants, only those who received the full regimen, or another defined set. No intention-to-treat or per-protocol population is described. These labels represent different analysis choices in general and should not be assigned to this record without explicit information.

The registry lists 5 enrolled participants, but does not report a denominator for the primary outcome or explain whether all enrolled participants contributed outcome data. Consequently, the enrollment figure should not be treated as the outcome denominator without further information. The record also does not report a prespecified statistical analysis plan, interim analyses, or rules for handling competing events. Those details are not reported in the registry record and should not be inferred from the listed endpoints.

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 registry’s serious adverse-event information lists 5 participants at risk and 0 affected. The separate other-adverse-event category lists 5 participants at risk and 5 affected. The group also lists 4 deaths. These are counts, not rates or estimates of comparative risk. No percentages or event-level descriptions are needed to read the figures as reported.

The categories should be kept distinct. The record does not explain the definitions or coding rules used for serious and other adverse events, nor does it state whether the deaths were considered adverse events. It also does not report the timing, causes, severity details, or relationship of these events to treatment. The counts alone cannot establish whether an event was caused by the regimen or whether a death occurred during a particular follow-up period.

Because the record describes one group and no comparator, these figures cannot quantify an excess or reduced safety risk relative to another treatment. They also do not show how many distinct participants experienced multiple events. The listed at-risk counts and affected counts are the available group summaries; additional interpretation would require definitions and participant-level or event-level detail that is not reported in the registry record.

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

The record establishes that a single-group study titled “Busulfan and Cyclophosphamide Followed By ALLO BMT” enrolled 5 participants and listed a disease-free survival count at 2 Years as its primary outcome. It also describes a regimen that includes busulfan, cyclophosphamide and allogeneic hematopoietic stem cell transplant infusion, alongside other named medications and biologic interventions. The brief summary frames the activity as a treatment guideline for routine clinical data collection in institutional databases.

The registry record does not report the primary outcome count or an analysis of that outcome. It therefore cannot show how many participants met the endpoint, estimate disease-free survival for the group, or determine whether outcomes differed from those under another regimen. No comparative treatment effect is reported, and the single-group design does not provide a like-for-like control comparison.

The adverse-event information is also limited to group counts: 0 affected among 5 at risk for serious adverse events, 5 affected among 5 at risk in the separate other-adverse-event category, and 4 deaths. These figures do not explain causation, timing, overlap, or the relationship of deaths to adverse events. They should not be interpreted as proof that the regimen caused or prevented any event.

In general, a registry entry records study characteristics and selected results, but its contents may not include every detail needed for a full statistical appraisal. Here, analysis populations, missing-data handling, multiplicity methods, endpoint assessment rules and the reason for termination are not reported in the registry record. That limits what can be concluded from the posted information. The record is informative about the study’s stated purpose, group, planned outcome and listed safety counts; it does not provide evidence for a comparative efficacy conclusion.

14. Why This Trial Matters Statistically

This record is a useful example of why the study design must be considered before interpreting an outcome. The primary endpoint is a count of participants with disease-free survival, but the registry describes a single group and no comparator. A count may be meaningful as a description of that group when its outcome definition and denominator are clear; it does not, by itself, answer what would have happened under a different treatment.

The registry also distinguishes between outcomes being listed and analyses being reported. It names 15 outcome measures but lists 0 analyses. Those are different kinds of information: an outcome definition states what is intended to be measured, while an analysis presents results using specified data and methods. Without a posted result, there is no estimate or uncertainty interval to assess for the primary endpoint.

The enrollment of 5 also underscores the importance of showing denominators and uncertainty when results are available. In general, small groups can yield imprecise estimates, and individual observations may have a substantial influence on summaries. That general point does not establish the magnitude or direction of any result in this study; the registry record does not report the primary outcome result needed to evaluate it.

Finally, the brief summary identifies routine clinical data collection as the stated purpose. Keeping that stated purpose distinct from an efficacy comparison helps prevent overinterpretation. The record documents a treatment guideline and clinical data collection context, but does not report a randomized comparison or a statistical analysis demonstrating a treatment effect. Its statistical importance lies in the distinction between a clinical record of one group and evidence from a comparative analysis.

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 trial-specific limitation is the single-group design. With allocation listed as NA and no separate comparator, the record cannot directly compare outcomes with another treatment. The lack of masking is recorded as NONE, but the registry record does not describe how outcomes were assessed or whether any protections against assessment bias were used.

Enrollment is listed as 5, and the record lists 0 analyses. No result for the primary disease-free survival outcome is reported, so there is no posted estimate or measure of precision to interpret. The registry lists 15 outcome measures, but does not report whether or how multiplicity was addressed. It also does not specify the primary outcome analysis population, denominator, handling of incomplete follow-up, or missing-data methods.

The endpoint is described as disease-free survival at 2 Years, but the record does not report a time-to-event analysis, censoring rules, or the detailed operational rules used to determine disease status. The listed conditions cover Acute Lymphoblastic Leukemia, Acute Myeloid Leukemia and Myelodysplastic Syndrome, yet condition-specific outcomes and subgroup analyses are not reported. Treatment doses, schedules and duration are also not reported in the registry record.

The record’s status is TERMINATED, while the reason for termination is not reported. That prevents an explanation of the status based on the registry information alone. The listed safety counts lack event timing, cause, attribution, and details about overlap between categories and deaths. The record also does not report the trial’s own sample-size justification or a statistical analysis plan. These limitations restrict interpretation of the record; they do not establish what the unreported results would have been.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Busulfan and Cyclophosphamide Followed By ALLO BMT — NCT01685411.
• Registry record last updated 2021-04-13; status last verified 2021-03.
• Results first posted 2021-04-13.
• 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

NCT01685411 is a single-group record titled “Busulfan and Cyclophosphamide Followed By ALLO BMT.” It lists phase NA, allocation NA, masking NONE, enrollment of 5, and status TERMINATED. The listed conditions are Acute Lymphoblastic Leukemia, Acute Myeloid Leukemia and Myelodysplastic Syndrome.

The group description names Allopurinol, Keppra, Busulfan, Cyclophosphamide, Filgrastim, antithymocyte globulin, Tacrolimus and Mycophenolate mofetil, followed by allogeneic hematopoietic stem cell transplant infusion. The primary outcome is a count of participants with disease-free survival at 2 Years. The registry lists 15 outcome measures and 0 analyses; no primary outcome result is reported.

Safety counts list 0 affected among 5 at risk for serious adverse events, 5 affected among 5 at risk for other adverse events, and 4 deaths. The reason for termination and further analysis details are not reported in the registry record.