This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for T-Regulatory Cell Kinetics, Stem Cell Transplantation, REGKINE (NCT00578461), a na na study. The primary outcome is Median Percentage of Treg Cells at 1 Year Post Transplant.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00578461 |
| Phase | NA |
| Condition | Leukemia, Cancer, Lymphoma |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 26 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Baylor College of Medicine |
| Results posted | Yes |
2. Clinical Question
Population
Patients with blood cancers or related blood disorders undergoing stem cell transplantation were the intended population. The registry describes leukemia, lymphoma, and myelodysplastic or myeloproliferative conditions among the reasons for considering transplant. It records 26 enrolled participants. For the primary endpoint, only 20 participants were included because only 20 had Treg values at 1 Year.
Intervention
Participants received a stem cell transplant from a matched sibling donor. The listed conditioning regimen includes Ara C, Cyclophosphamide, MESNA, and total body irradiation. The study focused on measuring regulatory T-cell frequency after transplant; it was not a comparison of alternative conditioning regimens.
Comparator
No separate comparator group is listed. The study has a single-group model, with allocation and phase recorded as NA. The registry therefore does not describe a randomized or like-for-like control comparison. Measurements over follow-up are part of the stated observation plan, not a separate treatment arm.
Primary question
The primary endpoint asks for the median percentage of Treg cells among total CD4+ cells at 1 Year post transplant. The broader stated investigative intent is to determine changes in the numbers and function of regulatory cells using methods to measure this population. The record does not report a numerical median, an inter-quartile range, or an analysis of change. It therefore states what was to be measured, but does not establish what the observed endpoint value was.
In practical terms, this is a post-transplant cell-measurement study, not a trial designed in the registry record to estimate a comparative treatment effect. Its primary question concerns the frequency of a particular immune-cell population at a specified follow-up time. The record describes transplantation as treatment for participants with serious blood disorders, but the posted endpoint is a cellular measure rather than survival, disease control, or a comparison of clinical outcomes. Those clinical outcomes cannot be inferred from the endpoint title.
3. Trial Design
The registry describes T-Regulatory Cell Kinetics, Stem Cell Transplantation, REGKINE, as a single-group study sponsored by Baylor College of Medicine. It lists 26 participants enrolled, a start date of 2007-10, primary completion in 2013-05, and a status of terminated. The phase and allocation are recorded as NA, and masking is listed as none. The reason for termination is not reported in the registry record.
Participants were to receive a stem cell transplant from a matched sibling donor. The arm description names a single Stem Cell Transplant group and lists conditioning with Ara C, Cyclophosphamide, MESNA, and total body irradiation. The record’s study rationale describes collecting donor stem cells and giving them to patients before or alongside intensive treatment. The study does not list a second treatment group or a comparator regimen.
The primary outcome concerns the median percentage of Treg cells among total CD4+ cells at 1 Year. Its description says that regulatory-cell frequency would be summarized at baseline and at each follow-up time point. This indicates an intended series of measurements, but the registry record does not provide the actual time-point results or a detailed schedule of visits. It also does not report the laboratory procedures, the criteria for a matched sibling, or further details of the transplant protocol.
The absence of a comparator is central to interpreting the design. A single-group study can describe measurements among its participants, but it does not directly separate changes associated with transplantation from changes that might occur for other reasons or under another treatment plan. The registry record also does not describe randomization, masking, or a planned comparative analysis. These design features mean that the posted record supports a description of the study’s intent and structure, not a causal comparison between transplant and an alternative.
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
| Stage | Stem Cell Transplant |
|---|---|
| STARTED | 26 |
| COMPLETED | 26 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Only 20 of the 26 patients enrolled were included in this analysis as only 20 patients have Treg values at 1 year.
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.
Population: A total of 26 patients were enrolled on the study and all of them received the conditioning treatment and the transplant.
| Characteristic | Unit | Stem Cell Transplant |
|---|---|---|
| Participants analysed | 26 | |
| Age, Continuous | years | 9.7 (SD 4.5) |
| Age, Categorical: <=18 years | Participants | 26 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 10 |
| Sex: Female, Male: Male | Participants | 16 |
| Region of Enrollment: United States | participants | 26 |
6. Primary Endpoint
The registry lists the primary outcome as Median Percentage of Treg Cells at 1 Year Post Transplant, measured over 1 Year.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | percentage of total CD4+ cells |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the median percentage of Treg cells at 1 Year post transplant, expressed as a percentage of total CD4+ cells. Treg refers to regulatory T cells. The endpoint is a frequency: it describes the proportion of the specified CD4+ cell population represented by Treg cells, rather than a count of all cells in the body or a clinical outcome such as disease status.
The registry identifies the summary measure as a median and the dispersion measure as an inter-quartile range. In general, the median gives the midpoint of observed values when they are ordered, while the inter-quartile range describes the spread of the central portion of those values. These summaries can be useful when measurements are unevenly distributed or affected by unusually high or low values. They do not, by themselves, show how participants changed from baseline or explain why values differed.
The endpoint description says that frequency would be summarized at baseline and each follow-up time point, and that the investigative intent included studying changes in numbers and function. However, the specifically named primary endpoint is the median percentage at 1 Year. The registry record does not report its numerical median or inter-quartile range, and it does not report a numerical change from baseline. The endpoint therefore identifies the intended measurement, but the posted record does not permit a quantitative interpretation of its observed level or change.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted record establishes that the study enrolled 26 participants and that the primary endpoint analysis included 20 because only 20 had Treg values at 1 Year. It identifies the endpoint as the median percentage of Treg cells among total CD4+ cells and names the inter-quartile range as its dispersion measure. It does not give the median, the inter-quartile range, or an inferential analysis. The registry lists no analysis records. Consequently, the numerical level and precision of the primary endpoint cannot be assessed from the posted results.
This absence matters for interpretation. A median without its observed value cannot show whether the measured frequency was high or low in this study. Without a dispersion estimate, readers cannot judge how much participant measurements varied. Without a reported baseline value or paired change analysis, the record cannot establish how the endpoint changed over follow-up. The endpoint description mentions planned summaries at baseline and each follow-up time point, but the actual summaries are not reported in the registry record.
The single-group design also limits what can be concluded. Measurements after transplant may describe the participants who had available results, but there is no listed control group against which to compare them. The record therefore does not estimate how the same endpoint would have differed under another treatment plan. It also does not support attributing any observed cellular pattern to transplantation alone. No such attribution should be read into the study rationale.
The available analysis population is narrower than the enrolled group: 20 of the 26 enrolled participants had endpoint values at 1 Year and were included in that analysis. The reason that each other participant lacked a value is not reported in the registry record. If availability of a Treg measurement is related to health, follow-up, or other factors, the analyzed group could differ from the full enrolled group; the record does not provide information to assess that possibility. This is a general missing-data concern, not evidence that such a difference occurred.
Safety information is also descriptive. The registry lists participants affected by serious and other adverse events and gives selected serious-event terms with percentages. These entries do not form a comparison with an untreated or alternative-treatment group. Nor do the selected terms, by themselves, establish the likelihood that a specific event was caused by a particular drug or by transplantation. Event attribution and context are not reported in the listed details.
Overall, the record documents a transplant-associated measurement study and selected safety counts, but not a numerical primary endpoint result or statistical analysis. It supports conclusions about the study’s intended measurement, its single-group structure, and the number included in the endpoint analysis. It does not support a quantitative conclusion about Treg frequency, a treatment effect, or a comparison of clinical benefit and harm.
9. Statistical Methods Explained
For the primary endpoint, the registry names the median and inter-quartile range. These are descriptive statistics. In general, a descriptive statistic condenses observed data without, by itself, testing a hypothesis or estimating a treatment contrast. The median represents the center of ordered measurements. The inter-quartile range describes variability around that center. Reporting both can communicate a typical measurement and some of the spread, but neither replaces a clear account of who contributed data or how measurements were collected.
What does the median describe?
The endpoint is a percentage of total CD4+ cells, so its median would summarize participant-level Treg percentages at 1 Year in the endpoint analysis population. It would not be a median change unless the analysis explicitly calculated change scores. The registry’s description mentions frequency summaries at baseline and follow-up, but the endpoint title does not specify a change-from-baseline statistic. The numerical median is not reported in the registry record, so its value cannot be interpreted.
In general, the median can be less influenced by extreme observations than an arithmetic mean. That can make it useful when data are skewed or contain unusually large or small values. The inter-quartile range complements it by showing the spread of the central part of the observed distribution. These summaries do not show the complete distribution, the precision of an estimated population value, or whether a difference is statistically distinguishable from chance. Such conclusions require additional reported information and an analysis suited to the study question.
What would an inferential analysis add?
An inferential analysis might estimate uncertainty around a summary or test a prespecified comparison. In general, a confidence interval gives a range of values compatible with the data and the method’s assumptions; it is not a guarantee that the true value lies within that particular interval. A hypothesis test addresses a defined null hypothesis and depends on both the data and the analysis plan. Neither a confidence interval nor a p-value for the primary endpoint is reported in the registry record. The record lists no analysis records, so there is no posted inferential result to interpret.
For repeated measurements, analysis choices can matter. In general, observations from the same participant are related, so a method that treats each time point as unrelated may misrepresent uncertainty. An analysis of change may also depend on which participants have measurements at each time point and whether those data are paired. The registry describes frequency summaries at baseline and each follow-up, but it does not report a repeated-measures model, a paired analysis, a testing procedure, or an adjustment for baseline. None should be assumed.
How should the analysis population be read?
The record states that only 20 of the 26 enrolled participants were included in the primary analysis because only 20 had Treg values at 1 Year. This is an available-measurement analysis population for that endpoint, as described in the registry. It does not establish why the other participants lacked values or whether the missing measurements were unrelated to their outcomes. In general, missing data can affect interpretation if the participants with observed measurements differ systematically from those without them. The registry does not provide enough information to evaluate that possibility or identify an imputation approach.
The record does not report a formal analysis population definition beyond the endpoint-specific inclusion statement. It does not say whether all enrolled participants were included in safety summaries under the same definition, whether any participants discontinued follow-up, or how measurements outside the stated time point were handled. Those details are not reported in the registry record.
What do design and planning assumptions mean?
The study is listed as single group, with allocation NA and masking none. General statistical interpretation follows from that structure: there is no randomized comparator in the record, and therefore no between-arm treatment contrast to estimate. Measurements over time can describe the observed course, but do not by themselves identify what would have happened to those participants under a different treatment. A single-group pattern is also vulnerable to influences unrelated to the intervention, including changes over time and differences in who has measurements available.
The registry record does not report a statistical analysis plan, a sample-size justification, planned interim analyses, or a prespecified multiplicity strategy. The sample-size planning assumptions described for planning illustrations are not evidence that this study was designed for a particular power, and a planning illustration is not observed power. General power calculations depend on assumptions about the effect to detect, variability, significance level, and design. Without the study’s own documented assumptions and a reported endpoint result, a planning calculation cannot establish the adequacy of this study’s enrollment or the certainty of its findings.
Multiplicity concerns arise in general when several outcomes, time points, or comparisons are tested. Repeated testing can increase the chance of at least one apparently notable result unless a suitable strategy is specified. The endpoint description mentions summaries at baseline and each follow-up, but it does not state how many time points were measured or whether formal tests were planned. An adjustment method and the trial’s handling of multiple analyses are not reported in the registry record. It is therefore not possible to determine whether multiplicity was addressed.
Finally, safety summaries and the cellular endpoint answer different questions. Descriptive event counts can indicate which events were recorded in the study group; they do not estimate comparative risk without a suitable comparator and adequate definitions of event ascertainment and follow-up. A median Treg percentage describes a cellular measurement; it does not establish clinical benefit or harm. Keeping these distinctions clear prevents descriptive summaries from being read as stronger causal evidence than the design and reporting support.
10. Multiplicity, Missing Data and Analysis Populations
The registry record does not report a multiplicity plan. The primary endpoint description says that T-cell frequency would be summarized at baseline and each follow-up time point, but it does not specify the number of time points, any formal hypothesis tests, or how multiple outcomes or comparisons would be handled. In general, when many tests are conducted, the chance of at least one apparently unusual result can increase. A planned statistical approach can address this concern, but no such approach is reported in the registry record.
For the primary endpoint, the registry states that 20 of the 26 enrolled participants were included because only 20 had Treg values at 1 Year. The specific reasons for unavailable values are not reported. Nor are the timing and pattern of missing measurements, any method for handling missing values, or an analysis comparing participants with and without endpoint data. The posted information therefore identifies the endpoint analysis count but does not show whether the analyzed participants represent the full enrolled group.
In general, missing data matter when the chance of having an observed measurement is connected to participant characteristics or outcomes. An analysis limited to observed values can be informative, but its interpretation depends on why values are missing and what assumptions are reasonable. The record does not provide the information needed to evaluate those assumptions. No imputation or sensitivity analysis is reported in the registry record.
The analysis population is described only for the primary endpoint. The registry does not provide further definitions of an intention-to-treat, per-protocol, or safety population, and it does not state how participants with incomplete follow-up were handled for other outcomes. The appropriate interpretation is therefore limited to the stated endpoint population and the posted safety counts, without assuming unreported analysis rules.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Stem Cell Transplant | 15 | 26 | 57.7% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Stem Cell Transplant | 16 of 26 |
Most frequent serious adverse event terms
| Event term | Organ system | Stem Cell Transplant |
|---|---|---|
| Infection with normal ANC or Grade 1 or 2 neutrophils - Catheter-related | Infections and infestations | 5 of 26 |
| Renal failure | Renal and urinary disorders | 3 of 26 |
| Pericardial effusion (non-malignant) | Cardiac disorders | 2 of 26 |
| Liver dysfunction/failure (clinical) | Hepatobiliary disorders | 2 of 26 |
| Infection with normal ANC or Grade 1 or 2 neutrophils - Blood | Infections and infestations | 2 of 26 |
| Allergic reaction/hypersensitivity (including drug fever) | Immune system disorders | 1 of 26 |
| Hypertension | Cardiac disorders | 1 of 26 |
| Coagulation - Other: Severe coagulopathy | Vascular disorders | 1 of 26 |
| Fever | General disorders | 1 of 26 |
| Death | General disorders | 1 of 26 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Stem Cell Transplant |
|---|---|---|
| Diarrhea | Gastrointestinal disorders | 4 of 26 |
| Vomiting | Gastrointestinal disorders | 4 of 26 |
| AST, SGOT | Metabolism and nutrition disorders | 4 of 26 |
| Mucositis/stomatitis (clinical exam) - Oral cavity | Gastrointestinal disorders | 3 of 26 |
| Infection with normal ANC or Grade 1 or 2 neutrophils - Catheter-related | Infections and infestations | 3 of 26 |
| PTT | Vascular disorders | 2 of 26 |
| Nausea | Gastrointestinal disorders | 2 of 26 |
| ALT, SGPT | Metabolism and nutrition disorders | 2 of 26 |
| Bilirubin (hyperbilirubinemia) | Metabolism and nutrition disorders | 2 of 26 |
| Calcium, serum-low (hypocalcemia) | Metabolism and nutrition disorders | 2 of 26 |
Serious events with the highest arm-level rate: infection with normal anc or grade 1 or 2 neutrophils - catheter-related (19.2%), renal failure (11.5%), pericardial effusion (non-malignant) (7.7%), liver dysfunction/failure (clinical) (7.7%), infection with normal anc or grade 1 or 2 neutrophils - blood (7.7%).
The registry lists 26 participants at risk for serious adverse events and 15 affected, and 26 at risk for other adverse events and 16 affected. These are descriptive counts for the single Stem Cell Transplant group. The record also lists selected serious-event terms with percentages: infection with normal ANC or Grade 1 or 2 neutrophils - Catheter-related, 19.2%; renal failure, 11.5%; pericardial effusion (non-malignant), 7.7%; liver dysfunction/failure (clinical), 7.7%; infection with normal ANC or Grade 1 or 2 neutrophils - Blood, 7.7%; and allergic reaction/hypersensitivity (including drug fever), 3.8%.
These entries describe events recorded in this study group; they are not a comparison with another treatment or a background rate. A participant may experience more than one event, so event categories should not be treated as mutually exclusive or added together to infer a total number of people affected. The selected terms are not a complete account of every event, and the listed percentages should be read as the registry reports them.
In general, adverse-event summaries do not by themselves establish causation. Interpretation also depends on definitions, severity, timing, duration, and attribution, details that are not reported in the listed record details. The safety figures therefore describe reported experience in this group but cannot determine how much risk was caused by a specific conditioning drug or by the transplant.
12. What the Result Does, and Does Not, Mean
The record’s principal contribution is its description of a study intended to measure regulatory T-cell frequency after matched sibling stem cell transplantation. It identifies the primary endpoint, the time point, the summary measure, and the number of participants with an available Treg value at 1 Year. It also records selected safety information for the transplant group.
Those details do not amount to a report of the primary endpoint result. The registry record does not provide the median percentage or its inter-quartile range. It does not report a numerical comparison between baseline and follow-up, a confidence interval, or a p-value. Readers cannot infer the direction or size of any change from the endpoint title or study rationale. No conclusion about the measured Treg frequency can be drawn without the missing result.
The design also defines what the study can address. Because it is a single-group study with no listed comparator, the record cannot establish whether the transplant regimen produced a different cellular measurement than another treatment would have produced. A change measured over time, if reported, would still require cautious interpretation because time, participant characteristics, and missing follow-up can affect observed patterns. The record does not report a comparative estimate or a causal analysis.
The study rationale describes transplantation as an approach for people with serious blood disorders, but the posted primary endpoint is a cell-frequency measure. It is not a direct measure of survival, disease control, or quality of life. The rationale should not be confused with evidence that any clinical outcome improved or worsened. The safety summaries likewise describe events in the study group but do not provide comparative risk estimates or establish event causation.
In short, the registry record supports a limited account of study structure, endpoint intent, endpoint availability, and selected adverse events. It does not provide enough outcome data or analysis detail to assess the numerical primary finding, its precision, or its clinical implications. Any broader conclusion would go beyond what the posted results report.
13. Why This Trial Matters Statistically
This study is statistically notable for the distinction between measuring a biological marker and demonstrating a comparative treatment effect. The primary endpoint is a median percentage of Treg cells among total CD4+ cells at 1 Year. That endpoint can describe an aspect of immune-cell composition, but it does not itself answer whether transplant changes clinical outcomes or whether one treatment strategy is better than another.
The single-group design makes that distinction especially important. Without a comparator, the study can describe the participants who had measurements, but it cannot directly estimate a treatment contrast. This is a general feature of single-group evidence, not a judgment about the value of collecting biological measurements. Such measurements may help characterize what happens after a procedure, while still leaving comparative and causal questions unanswered.
The difference between enrollment and endpoint availability is also relevant. The record lists 26 enrolled participants and 20 included in the primary endpoint analysis because only 20 had values at 1 Year. Statistical interpretation depends not just on the summary measure but on who contributes data. The reasons for missing endpoint values are not reported, so the potential effect of missingness cannot be assessed.
Finally, the registry lists safety counts and selected serious-event terms, yet these figures remain descriptive without a comparison group and fuller context. Statistical reading requires keeping the endpoint, analysis population, and design limitations together. This record illustrates why a clear endpoint definition and event counts are not substitutes for numerical results, precision estimates, or a documented analysis plan. Its statistical importance lies in clarifying what was intended to be measured and what the posted information does not establish.
14. 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 registry record provides limited outcome detail. Although it names the primary endpoint and specifies the median and inter-quartile range, it does not report either numerical summary. It also lists no analysis records. As a result, the primary endpoint cannot be evaluated quantitatively, and no estimate of its precision is available in the posted record.
Only 20 of the 26 enrolled participants were included in the primary endpoint analysis because only 20 had Treg values at 1 Year. The record does not explain why values were unavailable for the others, whether missingness affected additional follow-up times, or how missing data were handled. This limits assessment of how representative the endpoint analysis population may be of all enrolled participants.
The study is single group and has no listed comparator. That limits causal and comparative interpretation even if a numerical change were available. The record does not report the detailed measurement schedule, laboratory procedures, analysis of repeated measurements, or criteria for handling unusual or incomplete measurements. Those details are not reported in the registry record.
The registry does not state the reason for termination, a sample-size justification, a statistical analysis plan, an interim-analysis plan, or a multiplicity strategy. It also does not provide detailed safety-event definitions, attribution, timing, or duration in the registry record listed for the study. These absences do not establish that the information was never collected; they mean that it is not reported in the registry record. The posted information therefore supports a description of the study design and selected reported counts, but leaves important questions about endpoint estimation, missingness, and analysis conduct unresolved.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: T-Regulatory Cell Kinetics, Stem Cell Transplantation, REGKINE — NCT00578461.
- Registry record last updated 2016-04-22; status last verified 2016-03.
- Results first posted 2014-09-08.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00578461 is a Baylor College of Medicine, single-group study of T-regulatory cell measurements after matched sibling stem cell transplantation. The registry lists 26 participants enrolled, a start date of 2007-10, primary completion in 2013-05, and status as terminated. The reason for termination is not reported in the registry record.
The primary endpoint is the median percentage of Treg cells among total CD4+ cells at 1 Year, with inter-quartile range named as the dispersion measure. Only 20 participants had Treg values at 1 Year and were included in that analysis. No numerical endpoint result or analysis is reported. The registry lists serious and other adverse-event counts and selected serious-event terms for the transplant group. Because there is no comparator, these entries describe the study group rather than comparative treatment effects.