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 Clofarabine and Cytarabine in Treating Patients With Acute Myeloid Leukemia With Minimal Residual Disease (NCT00863434), a na phase 2 study. The primary outcome is Minimal Residual Disease as Assessed by Bone Marrow Flow Cytometry.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00863434 |
| Phase | Phase 2 |
| Condition | Adult Acute Myeloid Leukemia in Remission, Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities, Adult Acute Myeloid Leukemia With Inv(16)(p13;q22) |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Washington |
| Results posted | Yes |
2. Clinical Question
Population
Adults with acute myeloid leukemia (AML) in remission and minimal residual disease, including the listed AML subtypes with specified chromosomal abnormalities and recurrent AML. The registry record does not report further eligibility details or a separate definition of minimal residual disease for enrollment.
Intervention
The treatment group received G-CSF, clofarabine, and cytarabine. G-CSF was given subcutaneously once daily on days 1-5; clofarabine intravenously over 1 hour and cytarabine intravenously on days 2-5. Beginning approximately 1 month later, participants could receive an additional course if disease had not progressed and toxicity was not unacceptable.
Comparator
There was no separate comparator group. The trial is recorded as single-group, with allocation listed as not applicable and no masking. Its results therefore cannot provide a randomized comparison with another treatment or with no treatment.
Primary question
The primary endpoint was the median percentage of white blood cells that were blasts in bone marrow after treatment, assessed by flow cytometry. This describes the post-treatment measurement; a numerical result, baseline value, or comparison with a control group is not reported in the registry record.
3. Trial Design
This was a phase II, single-group trial sponsored by the University of Washington. The registry lists enrollment of 2 participants and a terminated status. The recorded start was 2009-02, and primary completion was 2011-02. The registry record does not state why the trial was terminated or provide details about how enrollment and treatment proceeded.
All participants were assigned to the treatment group described as colony stimulating factor and chemotherapy. The regimen included G-CSF, clofarabine, and cytarabine. G-CSF was administered subcutaneously once daily on days 1-5, with clofarabine given intravenously over 1 hour and cytarabine intravenously on days 2-5. Beginning approximately 1 month later, participants could receive an additional course if there was no disease progression or unacceptable toxicity. Doses and other administration details are not reported in the registry record.
Allocation is listed as not applicable, masking as none, and the model as single-group. This design does not include a concurrent control arm. Consequently, it can describe measurements and events among participants who received the regimen, but it cannot isolate treatment effects from other explanations by comparing outcomes between randomized groups. The registry record does not report a protocol rationale for the design, a target enrollment justification, or a statistical analysis plan.
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 | Treatment (Colony Stimulating Factor and Chemotherapy) |
|---|---|
| STARTED | 2 |
| COMPLETED | 2 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Treatment (Colony Stimulating Factor and Chemotherapy) |
|---|---|---|
| Participants analysed | 2 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 2 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 41.5 (34 to 49) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 2 |
| Region of Enrollment: United States | participants | 2 |
| Minimal Residual Disease (blast %) as Assessed by Bone Marrow Flow Cytometry | percent of white blood cells | 4.35 (4.3 to 4.4) |
6. Primary Endpoint
The registry lists the primary outcome as Minimal Residual Disease as Assessed by Bone Marrow Flow Cytometry, measured over Post-treatment.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | percent of white blood cells |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is minimal residual disease assessed by bone marrow flow cytometry after treatment. It is defined as the percentage of white blood cells in the bone marrow that are blasts. The planned summary measure is the median, with the full range describing the spread of observed values. A numerical median and range are not reported in the registry record.
In general, flow cytometry identifies and characterizes cells using measurable features, allowing a study to quantify the proportion of cells classified as blasts in a specimen. Measuring that proportion after treatment gives a description of residual blast burden at that assessment. It is not, by itself, a comparison with the participant’s pretreatment status. The registry record does not report a baseline result, a change-from-baseline endpoint, or the timing of the post-treatment assessment beyond the phrase post-treatment.
The median is a descriptive measure of the center of observed values and is less influenced by unusually high or low observations than the arithmetic mean. The full range communicates the lowest and highest observed values, but with very few participants it can be unstable and does not show how values are distributed between those endpoints. Neither the median nor the range can be interpreted from this record because the actual endpoint values are not reported.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record describes a small, terminated, single-group phase II trial, with enrollment of 2 participants. Its primary endpoint is specified, but the numerical post-treatment median and full range are not reported in the registry record. No primary outcome analysis is listed. It is therefore not possible to describe the observed level of bone marrow blasts, the variability in that measurement, or the precision of an estimated treatment-associated change.
The design also limits what could be concluded even if the endpoint values were available. There is no comparator group, so a post-treatment measurement would describe participants who received the regimen, not a difference attributable to treatment relative to another group. A baseline-to-post-treatment comparison is not specified in the available endpoint details. Without such information, the record does not establish whether the endpoint changed over time.
The registry lists safety counts for the treatment group: 0 of 2 participants at risk were recorded as having a serious adverse event, while 2 of 2 were recorded as having other adverse events. These are counts in a small group, not precise estimates of how often such events would occur in a broader population. The specific serious and other adverse event terms are not reported. Deaths are not reported in the record.
These findings should be read as an incomplete descriptive account, not as evidence for or against a treatment effect. The terminated status is recorded, but the reason for termination is not reported in the registry record. The record also does not explain whether endpoint or safety data were collected for all enrolled participants, or whether the recorded enrollment represents everyone who received treatment. Those uncertainties prevent a fuller assessment of the posted data.
In general, statistical precision depends on the amount and variability of observed data. With enrollment of 2, a summary can be strongly influenced by each participant’s result, and a meaningful estimate of between-participant variability is difficult to establish. Since the primary endpoint values and an inferential analysis are not reported, no confidence interval or hypothesis test can be interpreted for the main question.
9. Statistical Methods Explained
The registry identifies a median and full range as the primary endpoint summary, but does not list an analysis for the endpoint. The record lists 3 outcome measures overall; details for the other outcome measures are not reported in the registry record. It lists no analyses. Accordingly, the statistical information available is descriptive: the endpoint definition, its intended summary, the enrollment count, and safety event counts.
What does a median describe?
In general, the median is the central value after observations are ordered. It can be useful when measurements are skewed or when unusually large or small values might pull an arithmetic mean away from the typical observation. The full range gives the minimum and maximum observed values. It does not indicate how closely the remaining observations cluster, and it can be especially sensitive to individual observations in a small sample.
Here, the registry record names those summaries but does not report the underlying endpoint values. The intended summaries therefore cannot be inspected or interpreted. The full range is not a confidence interval: it describes observed values, whereas a confidence interval is an inferential estimate of uncertainty about a population quantity under specified assumptions.
What would a confidence interval add?
In general, a confidence interval expresses the precision of an estimate by giving a range of values compatible with the data and the method used. Its interpretation depends on the endpoint, design, model, and assumptions. The registry record does not report a confidence interval or enough numerical endpoint information to assess one. No interval should be inferred from the enrollment count or from the stated summary measure alone.
A p-value, when used, measures how compatible data are with a specified null model under the analysis assumptions. It is not a measure of the size or clinical importance of an effect. No p-value or hypothesis test for the primary endpoint is reported in the registry record. Because the trial has no comparator group and the endpoint is reported as a post-treatment measure, the record does not support a treatment-versus-control test.
How should the planning assumptions be read?
General planning illustrations are described using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They are described as targeting a stated fraction of an observed effect. These assumptions do not describe the actual trial design: the trial is single-group and has no two-arm allocation. The illustrations are planning scenarios, not observed power, and do not explain the trial’s enrollment of 2. The registry record does not report the trial’s own sample-size justification or the values needed to interpret a specific planning scenario.
In general, over-dispersion means that observed variability exceeds what a statistical model assumes. If it is ignored, uncertainty can be understated and inferential results can be misleading. The registry record does not report a model or evidence of over-dispersion for this endpoint, so no claim about its presence or handling can be made.
What can the safety counts establish?
Counts and denominators describe how many participants in the recorded group had an event. They do not show event timing, duration, severity beyond the serious-event classification, or whether participants had multiple events. The record does not list event terms or explain how events were coded. With only 2 participants at risk, these counts cannot be treated as stable estimates for other populations.
More generally, analysis choices matter: defining the outcome, selecting the analysis population, handling missing observations, and specifying comparisons can affect the interpretation. The registry record does not report these choices for the primary endpoint. Without the numerical outcomes and analysis details, recalculation from summary statistics is not possible, and there is no sponsor analysis to compare with a recalculation.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 3 outcome measures, but the details for the other outcome measures are not reported in the registry record. It does not describe a multiplicity adjustment or explain how conclusions across outcomes were to be managed. In general, testing multiple outcomes can increase the chance of observing a nominally notable result by chance; adjustment or a prespecified hierarchy may be used to address that issue. No such approach is reported, and no outcome analyses are listed.
The primary endpoint is defined as a post-treatment bone marrow measurement, but the record does not report numerical results, a baseline measurement, or an analysis population. It does not state whether every enrolled participant contributed an endpoint value, how missing endpoint data were handled, or whether any participant was excluded from an analysis. Missingness should not be assumed absent merely because these details are not reported.
In general, an analysis population might include all enrolled participants, all treated participants, or participants meeting specified criteria. The choice can affect the question answered and the interpretation of estimates. The registry record does not identify an analysis population or provide a statistical plan specifying one.
These omissions prevent assessment of whether outcome selection, missing data, or analysis-population choices could have influenced the reported findings. They also mean that no multiplicity-adjusted result, missing-data sensitivity analysis, or population-specific estimate can be described from the registry record.
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 |
|---|---|---|---|
| Treatment (Colony Stimulating Factor and Chemotherapy) | 0 | 2 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment (Colony Stimulating Factor and Chemotherapy) | 2 of 2 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment (Colony Stimulating Factor and Chemotherapy) |
|---|---|---|
| Exacerbation of depression | Psychiatric disorders | 1 of 2 |
| Left shoulder pain | General disorders | 1 of 2 |
| Macular Rash | Skin and subcutaneous tissue disorders | 1 of 2 |
The treatment group had 2 participants at risk for serious adverse events, and 0 were recorded as affected. For other adverse events, 2 participants were at risk and 2 were recorded as affected. These are participant counts, not a detailed accounting of event episodes. The registry record does not report the specific event terms, timing, duration, or severity for the other adverse events. It also does not describe the criteria used to classify serious events.
The recorded group is very small, so the counts provide only a limited description of what was recorded among these participants. They should not be read as precise estimates of event frequency in a larger population, nor do they establish that an event cannot occur. Deaths are not reported in the registry record; the missing death count does not establish that there were no deaths.
These safety figures are not a comparison between treatments. With no control group, differences in event counts against another regimen or against no treatment cannot be assessed from this trial record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a phase II, single-group study of clofarabine and cytarabine, with G-CSF, was conducted in adults with AML and minimal residual disease. It records enrollment of 2 participants, a terminated status, a defined post-treatment bone marrow flow cytometry endpoint, and treatment-group safety counts. It does not report numerical results for the primary endpoint or any analysis of that endpoint.
As a result, the record cannot show what post-treatment blast percentages were observed, how those measurements varied, or whether they changed from baseline. It also cannot show whether outcomes differed from those under another treatment, because no comparator group is recorded. The safety counts describe only the participants at risk in this treatment group, and details about the adverse events are not reported.
In general, a descriptive measurement after treatment is not equivalent to evidence that treatment caused a change. Causal interpretation requires an appropriate design and analysis, and a comparison group is one way to address alternative explanations. The single-group structure does not support a randomized treatment comparison.
The record also does not explain why the trial was terminated, whether the planned treatment courses were completed, or why numerical outcome analyses are absent. Those uncertainties matter when considering how complete the available account is. The status and enrollment count alone do not explain the reason for termination or the completeness of data collection.
The appropriate interpretation is therefore limited: the registry records the trial’s design and some safety counts, but not the numerical primary endpoint results needed to characterize the main outcome. Nothing in this record establishes benefit, lack of benefit, or a comparative safety profile.
13. Why This Trial Matters Statistically
This trial illustrates why a clearly named endpoint is not enough to interpret a clinical study. The registry specifies a measurable post-treatment quantity: the percentage of white blood cells that are blasts in bone marrow, assessed by flow cytometry and summarized by a median and full range. Yet without the numerical observations, readers cannot evaluate the endpoint’s observed level, spread, or precision.
The design is also central to interpretation. A single-group study can provide descriptive information about participants who receive a regimen, but it cannot make a randomized comparison against a control group when none is present. This distinction is important when a registry describes an intervention and a clinical outcome: the presence of both does not, on its own, establish a treatment effect.
The enrollment of 2 highlights the limits of drawing broad conclusions from a very small group. In general, a small sample makes summaries sensitive to individual observations and limits the ability to characterize variability. Here, the endpoint values are not reported, so even a descriptive account of the observed measurements is unavailable.
The record also shows why completeness of reporting matters. A termination status, absent endpoint values, no listed analyses, and missing information about analysis populations and missing data leave important questions unanswered. The safety counts are interpretable only as counts in the recorded group; they do not replace detailed event descriptions or a comparator-based safety assessment.
Statistically, this study is useful as an example of the difference between a protocol-level endpoint description and analyzable results. A defined measurement says what was intended to be assessed. Numerical results and transparent analysis details are needed to understand what was observed and how uncertain any inference may be.
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 principal limitation is the absence of numerical primary endpoint results. Although the endpoint and its intended summaries are described, the post-treatment median and full range are not reported in the registry record. No analysis is listed, so the primary question cannot be evaluated from the available results.
Enrollment was 2, and the trial was single-group, with no comparator. These features limit both descriptive precision and comparative interpretation. A baseline endpoint value or a change-from-baseline analysis is not reported, so the post-treatment endpoint cannot be interpreted as a documented change.
The trial is recorded as terminated, but the reason is not reported in the registry record. Details about treatment completion, follow-up, and participant-level endpoint availability are also not reported. The record does not specify the analysis population, how missing data were handled, or whether any participants were excluded from analyses.
The safety information is limited to participant counts. Specific adverse event terms, event timing, duration, and the serious-event definition are not reported. Deaths are not reported in the registry record. The small number at risk also means the safety counts should not be treated as precise estimates beyond this group.
The record does not report a trial statistical analysis plan, a sample-size justification, or the reason for selecting the endpoint summary. It also does not describe multiplicity handling for the 3 listed outcome measures. These gaps limit assessment of design rationale and analytic choices, rather than establishing that any particular approach was or was not used.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clofarabine and Cytarabine in Treating Patients With Acute Myeloid Leukemia With Minimal Residual Disease — NCT00863434.
- Registry record last updated 2017-05-15; status last verified 2017-05.
- Results first posted 2017-05-15.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
This University of Washington phase II trial evaluated clofarabine and cytarabine with G-CSF in adults with AML and minimal residual disease. It was single-group, had no masking, enrolled 2 participants, and is recorded as terminated. The record lists a post-treatment bone marrow flow cytometry endpoint: the median percentage of white blood cells that are blasts, with the full range as the dispersion measure.
Numerical primary endpoint results and analyses are not reported in the registry record. Serious adverse events were recorded for 0 of 2 participants at risk; other adverse events were recorded for 2 of 2. Event terms and deaths are not reported. The record does not state why the trial was terminated or provide details on missing data, analysis populations, or the statistical plan. The available information supports a description of the study design and recorded safety counts, but not an estimate of treatment effect.