Prospective Cohort for the Evaluation of Biomarkers Following HCT (BMT CTN 1202): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prospective Cohort for the Evaluation of Biomarkers Following HCT (BMT CTN 1202) (NCT01879072), a registered phase not stated study. The primary outcome is Number of Participants Providing Biologic Samples.

2. Clinical Question

The registry record concerns a prospective cohort of people treated with allogeneic hematopoietic cell transplantation (HCT) at BMT CTN centers. Its central aim is to establish a shared collection of biologic samples that can support future correlative research. The registry describes the intended resource as including at least 1500 biologic samples collected prospectively.

The primary question recorded is operational: how many participants provide biologic samples within the stated timeframe of two years from HCT? This is a count of participants, rather than a comparison of clinical outcomes between treatment groups. The record does not state a treatment-effect question or a randomized comparison. Allocation is not stated, and the registry explicitly notes that this is not a like-for-like control comparison.

The information posted does not report the observed count of participants who posted samples. It therefore does not establish whether the intended resource target was reached. Nor does the record provide an analysis connecting sample provision with complications, mortality, biomarkers, or any other clinical outcome. Those future correlative studies are described as a purpose for the sample resource, not as findings from this cohort record.

The enrollment is 1860. That figure describes enrollment, not the primary endpoint result: enrollment and the number providing biologic samples are different measures. The registry does not report how many enrolled participants contributed samples, how many had samples available at the stated endpoint timeframe, or how missing sample collection was handled. The clinical question can therefore be identified from the record, but its observed answer is not reported in the registry record.

3. Trial Design

This is a prospective, multicenter cohort, as indicated by the official title and registry description. The record identifies the Medical College of Wisconsin as sponsor and reports an enrollment of 1860. The study status is COMPLETED. Its recorded start is 2013-06 and its primary completion is 2016-09.

The protocol’s stated goal is to establish a shared bio specimen resource from patients treated in BMT CTN centers. The brief summary describes an intended collection of at least 1500 biologic samples for future allogeneic HCT correlative studies. This objective is a resource-building aim, not a treatment assignment or a comparison of outcomes across randomized groups. The registry says allocation is not stated and cautions that arms are not a like-for-like control comparison.

The primary outcome is titled “Number of Participants Providing Biologic Samples.” It is a participant count, with a timeframe of two years from HCT. No value for that outcome is included in the posted results. Enrollment should not be substituted for this endpoint: the record does not state that every enrolled participant provided a sample.

The record lists one outcome measure and zero analyses. It does not report a detailed statistical analysis plan, a sample-size justification, eligibility criteria, recruitment procedures, or how the cohort was divided into any groups. Those details are not reported in the registry record. The stated enrollment and the intended resource target describe separate aspects of the study and do not, on their own, establish the number of samples actually collected.

Because the record does not describe a randomized intervention or control group, conventional between-arm treatment-effect interpretation is not appropriate. The cohort’s main stated purpose is to assemble a resource for future studies. Whether collected material was subsequently used, and what results any such future studies produced, is 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 Number of Participants Providing Biologic Samples, measured over Two years from hematopoietic stem cell transplant.

The primary endpoint is the number of participants providing biologic samples, measured within two years from HCT. It counts participants, rather than the number of samples, the proportion with a particular biomarker, or the frequency of a transplant complication. The endpoint description says that prospectively collected samples are intended to form a shared resource for future correlative studies.

A participant count is useful for describing whether a cohort has contributed material to a research resource. It directly addresses the operational aim of sample collection. It does not, by itself, describe the clinical characteristics of the samples, their completeness or quality, or the scientific validity of later analyses. Nor does it establish that a biomarker predicts a complication or mortality; those are potential questions for future correlative work, not reported results of this endpoint.

The registry record does not report the observed number of participants who provided samples. The intended goal of at least 1500 biologic samples is not the same measure as a participant count, and the record does not report whether that goal was attained. The enrollment of 1860 likewise cannot stand in for the primary result. The endpoint’s definition and timeframe are recorded, but the outcome value and any explanation of unavailable samples are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a participant count. A count records how many people meet a defined condition—in this case, providing biologic samples within two years from HCT. It is not an estimate of a treatment contrast, and it does not require an interpretation in terms of a difference between randomized arms. The record does not report the resulting count, so no estimate of sample provision can be evaluated.

What does a count tell the reader?

A count is an absolute description of how many participants met an outcome definition. Its interpretation depends on knowing both the definition and the population in which it was assessed. Here, the definition and timeframe are stated, while the observed endpoint value is absent. Enrollment of 1860 gives a cohort size, but it does not disclose how many participants contributed samples. The record also does not report the number of samples collected or how the participant count relates to the intended goal of at least 1500 biologic samples.

Counts can be useful for describing feasibility and resource development. They do not automatically establish representativeness, completeness, or the usefulness of collected material for later research. Those questions would require additional information, such as how participants with and without samples differed and how sample availability was assessed. Such details are not reported in the registry record.

Why are effect estimates and confidence intervals relevant?

In an inferential analysis, an estimate describes the quantity calculated from the observed data, while a confidence interval communicates uncertainty around that estimate under the analysis assumptions. A narrow interval generally indicates greater precision than a wide interval, though interpretation also depends on the outcome and design. This is a general explanation; the registry record does not post an estimate or confidence interval for the primary endpoint.

A p-value, when used, addresses how compatible the observed data are with a specified statistical model and null hypothesis. It does not measure the size or importance of an effect. No p-value or hypothesis test is reported for this cohort. With no reported analysis, readers cannot assess statistical significance or the precision of a primary outcome estimate.

How should planning calculations be read?

Sample-size calculations are planning tools that describe the sample size needed under stated assumptions. They are not observed outcomes and are not a substitute for an analysis of collected data. The planning illustration associated with this record is described as using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a stated fraction of an observed effect. Those are assumptions for an illustration, not evidence that the cohort was designed or conducted as a two-arm randomized trial.

The registry identifies this study as not a randomized comparison and says allocation is not stated. The illustration’s equal-allocation assumption therefore should not be read as a description of actual cohort groups. The planning values are also not observed power. Power is a design concept tied to assumptions about a specified effect and analysis; a planning calculation does not show that a study had a particular probability of detecting an effect after data collection. No analysis of the primary endpoint is listed, and the registry record does not report a trial-specific sample-size justification.

What does zero listed analyses imply?

The record lists zero analyses. This means the registry posting contains no analysis entry to interpret for the outcome. It does not reveal whether an analysis was conducted outside the posted record, and it does not allow readers to infer an unreported estimate. The appropriate conclusion is limited to the posted information: no inferential analysis is reported in the registry record.

These distinctions are especially important for a resource-building cohort. The stated aim concerns collecting material for future correlative studies, while the primary registered endpoint counts participants providing samples. Neither the stated aim nor the planning assumptions provide evidence about a biomarker’s predictive performance or a clinical outcome. Any such conclusion would require a defined analysis and results, which are not 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("Allogeneic Hematopoietic Stem Cell Transplant")
n      <- c(1709)
events <- c(1709)
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  1709  1709  100.0  99.8  100.0  99.8  100.0  99.8  100.0

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity refers to the risk of false-positive findings when multiple hypotheses or outcomes are tested. Analysts may address that risk through prespecified testing strategies or adjustments, depending on the goals and design. This is a general statistical consideration; the registry does not report a multiplicity strategy. It lists one outcome measure and zero analyses, so no family of posted inferential tests is available to assess.

The record does not report a detailed statistical analysis plan, whether analyses were prespecified, or whether any interim analyses were conducted. These items are not reported in the registry record. With no analysis results, readers cannot determine whether any adjustment for multiple testing was used or needed for analyses performed outside the posting.

Missing data are also relevant to a participant-count endpoint. Participants may not have provided samples, and the posted record does not explain whether that reflects noncollection, withdrawal, unavailable material, or another reason. It does not report missingness by center or participant characteristics, nor how missing or incomplete sample data were handled. The endpoint count itself is not reported, so the scale of any missingness cannot be assessed.

The registry does not specify the analysis population used for the primary outcome, such as whether it included all enrolled participants or a defined subset. The primary endpoint description identifies participants providing samples, but no analysis population or exclusions are reported. The safety entries use a reported at-risk count of 1709; the record does not explain how that population relates to the enrollment of 1860 or define the safety observation period in further detail. No assumptions about missing data or analysis populations should be inferred from these figures.

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.

The registry lists a group titled Hematopoietic Stem Cell Transplant with 1709 participants at risk. It reports 0 serious adverse events and 0 other adverse events in the listed fields. The deaths field has no numeric result. These entries are descriptive safety counts as posted; they are not a comparison between treatment groups.

A zero count in a registry field should be read narrowly. It indicates that the posted entry is zero for that category, not that every possible adverse event was assessed or that no event could have occurred outside the reported data. The record does not provide serious-event definitions, event ascertainment details, follow-up completeness, or an explanation for the unreported deaths value. The group’s at-risk count is not the same as the enrollment figure, and the record does not explain the difference.

The registry also lists no top serious adverse event terms. These safety entries do not include an analysis or uncertainty estimate. They should not be interpreted as proof of safety, as evidence of a treatment effect, or as a complete account of all clinical events. The posted results support only the limited statement that the listed counts are zero for the reported categories, with deaths not reported as a numeric value.

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

The record documents a prospective, multicenter cohort whose stated purpose is to build a shared biologic sample resource for future allogeneic HCT correlative studies. It reports enrollment of 1860, a primary endpoint focused on participants providing biologic samples, and a timeframe of two years from HCT. These registry entries describe the study’s scope and intended measurement.

The record does not report the observed primary endpoint count. Therefore, it does not establish how many participants provided samples or whether the goal of at least 1500 biologic samples was reached. Enrollment alone cannot answer either question. The record also does not report results showing whether samples were suitable for later work or whether a biomarker predicted complications or mortality.

There is no posted inferential analysis for the primary endpoint: the registry lists zero analyses and supplies no estimate, confidence interval, or p-value. This means the precision of the endpoint result cannot be assessed from the record. It does not mean that an effect was found to be absent, nor does it establish that an unreported analysis was never performed.

The safety fields report zero serious adverse events and zero other adverse events among 1709 participants at risk, while deaths are not reported as a numeric value. These entries are limited to the categories and data shown. The registry does not give enough information to conclude that all possible events were captured or to interpret the safety counts as a comparative treatment result.

Overall, this record describes a cohort and its resource-building objective, rather than a randomized test of a treatment. It can be used to understand the registered purpose, endpoint definition, enrollment, and posted safety entries. It cannot answer whether a particular treatment works, whether a biomarker predicts an outcome, or whether the planned sample resource was successfully assembled. Those conclusions would require results and analyses not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable because its stated primary objective is resource development, not a conventional comparison of treatment outcomes. A prospective collection can provide material for later correlative research, but the value of that resource depends on what was collected and how its availability is characterized. The registry identifies the intended use of the samples while leaving the achieved participant count unreported.

The distinction between enrollment and endpoint completion is important in interpreting cohort studies. The enrollment figure of 1860 does not tell readers how many participants posted samples. Likewise, the stated goal of at least 1500 biologic samples is not a reported collection result and is not the same unit as the primary participant-count endpoint. Clear reporting of both could help readers judge the progress and scope of a sample resource, but the observed values are not reported in the registry record.

The record also illustrates why the design should guide statistical interpretation. There is no stated randomized allocation or like-for-like control group, so a treatment contrast should not be inferred. The posted safety counts are not a substitute for an efficacy analysis, and the absence of a listed analysis is not a null finding.

For biostatisticians and clinical researchers, the case highlights the importance of distinguishing aims, endpoints, and analyses. The resource-building aim may enable future scientific questions, but it is not itself evidence that a biomarker predicts an outcome. The registry gives readers enough information to identify the intended cohort purpose and measure, while its missing endpoint result and analysis limit quantitative conclusions. That transparency about what is and is not posted is central to responsible interpretation.

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 direct limitation is that the primary outcome value is not reported in the registry record. The intended endpoint is the number of participants providing biologic samples within two years from HCT, but no observed count is posted. The intended goal of at least 1500 biologic samples cannot be treated as an achieved collection, and the enrollment of 1860 cannot substitute for the endpoint result.

The record provides little detail for evaluating how the cohort was assembled or how representative it may be. Eligibility criteria, recruitment procedures, center-level participation, and participant characteristics are not reported in the registry record. The number of samples per participant, sample completeness, and sample availability by participant or center are also not reported.

There is no listed analysis of the primary endpoint. The record does not provide an analysis population, handling of missing data, confidence interval, or statistical analysis plan. It does not state whether interim analyses were conducted or offer a trial-specific sample-size justification. The planning illustration uses assumptions involving equal allocation between two arms, even though the registry states this is not a randomized comparison; those assumptions should not be mistaken for the cohort’s actual design.

Safety interpretation is limited as well. The registry reports 1709 participants at risk and zero serious and other adverse events, but deaths are not reported as a numeric value. Event definitions, ascertainment methods, follow-up detail, and the relationship between the at-risk count and enrollment are not explained. These limitations restrict conclusions about endpoint completion, missingness, safety completeness, and the use of the resource in later research.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Prospective Cohort for the Evaluation of Biomarkers Following HCT (BMT CTN 1202) — NCT01879072.
• Registry record last updated 2022-12-09; status last verified 2022-12.
• Results first posted 2018-05-29.
• 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 NCT01879072, a prospective multicenter cohort for evaluating biomarkers following allogeneic HCT. The sponsor is the Medical College of Wisconsin. The study is COMPLETED, with enrollment of 1860, a start of 2013-06, and primary completion of 2016-09.

The stated goal is to establish a shared biologic sample resource, with an intended collection of at least 1500 biologic samples. The primary outcome counts participants providing samples within two years from HCT. Its observed value is not reported in the registry record. The record lists one outcome measure and zero analyses, and states that this is not a randomized comparison.

For the Hematopoietic Stem Cell Transplant group, the record lists 1709 participants at risk, 0 serious adverse events, and 0 other adverse events. Deaths are not reported as a numeric value. No inferential analysis or detailed statistical plan is reported in the registry record.