Standard Idarubicin and Cytarabine for the Treatment of Acute Myeloid Leukemia (AML): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Standard Idarubicin and Cytarabine for the Treatment of Acute Myeloid Leukemia (AML) (NCT00422591), a na phase 2 study. The primary outcome is Complete Response (CR) Rate.

2. Clinical Question

The study also names event-free survival and overall survival as secondary outcomes. These outcomes concern time-to-event experience rather than only whether a participant meets a response definition at an assessment. Their presence among the stated outcomes does not establish that estimates or analyses were reported. The registry record lists no analyses and does not report results for either survival outcome.

The question is therefore descriptive: it concerns the recorded experience of patients receiving this regimen in a single group. Without a concurrent comparator, the study cannot estimate a treatment contrast against another regimen or against no treatment. The record's objective is to evaluate complete response and survival outcomes in newly diagnosed AML, but the available registry information does not provide the numerical results needed to characterize those outcomes.

3. Trial Design

This is a phase 2, single-group clinical study sponsored by M.D. Anderson Cancer Center. The registry lists enrollment of 175, a start date of 2006-12, primary completion in 2017-01, and status as completed. These record-level details describe the study but do not establish how many participants contributed data to each outcome analysis.

The intervention is the combination of idarubicin and cytarabine. The regimen description gives intravenous dosing schedules and distinguishes cytarabine schedules by age: patients younger than 60 years are assigned the stated day 1-4 schedule, while those older than 60 years have the stated day 1-3 schedule. The record does not explain the treatment rationale or provide additional details about treatment delivery, adherence, or subsequent care.

Allocation is listed as NA, masking is listed as none, and the model is single group. There is no separate control arm described. As a result, observed outcomes in this cohort would not, by themselves, distinguish effects of the regimen from other influences on participants' outcomes. In a single-group study, comparisons with external results can also be difficult to interpret when populations, outcome definitions, follow-up, and care differ.

The registry lists complete response rate as the primary outcome, with a timeframe of up to 2 months. Event-free survival and overall survival are listed as secondary outcomes. The registry record does not report the protocol's analysis plan, the timing or frequency of survival assessments, or the methods used to handle censoring. It also does not report eligibility criteria beyond the description of newly diagnosed AML, participant characteristics, or a sample-size justification. Those omissions limit assessment of the planned design and of how representative the enrolled group may be.

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.

Before assignment: Of the 175 participants registered, six were never treated.

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 Complete Response (CR) Rate, measured over Up to 2 months.

The primary outcome is complete response (CR) rate, recorded in participants and assessed up to 2 months. In general, a response endpoint classifies whether each participant meets a prespecified clinical definition at an assessment. A response rate then describes the proportion meeting that definition in the population evaluated. It can provide a concise measure of early disease response, but it does not by itself describe how long a response lasts or what happens after the assessment.

The registry defines CR using normalization of marrow and peripheral blood findings. The definition includes a marrow blast threshold of < 5%, cellularity >10%, no circulating blasts, and specified neutrophil and platelet thresholds. These criteria make the outcome more explicit than an undefined judgment of response. However, the record does not report the number of participants meeting the definition, the denominator used for the rate, or the resulting estimate. It is therefore not possible to describe the observed CR rate or its precision from the registry information.

Event-free survival and overall survival are listed as secondary outcomes. In general, time-to-event endpoints retain information about when an event occurs, rather than reducing follow-up to a simple event count at one assessment. Their interpretation depends on the event definition, follow-up, censoring, and analysis population. Those details and the numerical survival results are not reported in the registry record. Naming these outcomes should not be mistaken for evidence that estimates are available.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study's single-group model is central to interpreting its statistics. In general, a single-group study estimates outcomes in the participants who receive the intervention. It does not directly estimate a between-group treatment difference because no concurrent comparator group is described. An observed response can be summarized, but attributing that response to the regimen alone requires caution: patient mix, disease course, assessment practices, and other care can affect outcomes. The registry record does not provide information that would quantify or resolve these influences.

What does a response rate convey?

In general, a response rate is a proportion: participants who meet a defined response criterion relative to an analysis denominator. The criterion needs to be stated, as it is for CR in this record, and the denominator and handling of participants without an assessment also matter. A confidence interval expresses the statistical uncertainty around an estimate under the analysis assumptions. A narrower interval indicates greater precision, while a wider interval indicates less precision. No CR estimate, denominator, or confidence interval is reported in the registry record, so neither the response magnitude nor its precision can be discussed.

For a binary outcome such as whether CR criteria are met, the count and the denominator are both needed to interpret a rate. A count alone does not show how common the outcome was in the analyzed group, while a rate without a clearly defined denominator can be difficult to evaluate. The registry identifies the endpoint unit as participants, but does not report the outcome count or analysis denominator. The enrollment figure is not a substitute for an endpoint-specific denominator, since the record does not establish that every enrolled participant contributed an assessable primary outcome.

How should survival outcomes be understood?

In general, event-free survival and overall survival are time-to-event outcomes. They use information about the time until a defined event, and may include participants whose event has not occurred by the end of their observed follow-up. Such participants are commonly treated as censored at their last known follow-up in time-to-event analyses. Censoring is a statistical way to retain partial follow-up; it is not the same as assuming that no event will ever occur. The validity of an analysis depends on the event definitions, follow-up procedures, and assumptions about censoring.

The registry lists EFS and OS but does not specify the event definitions, analysis methods, censoring approach, follow-up distribution, estimates, or uncertainty. In general, survival curves can describe the estimated probability of remaining event-free or alive over time, and confidence intervals can communicate uncertainty in those estimates. Those concepts explain how survival outcomes are often analyzed, but they do not supply missing study results. No specific survival conclusion can be drawn from outcome names alone.

What is the role of the planning illustration?

The record describes a sample-size planning illustration based on a fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It states that time-to-event calculations use a total event count and other calculations use participants per arm. These are planning assumptions, not a description of the actual single-group design. In particular, an equal-allocation two-arm planning scenario does not make this clinical study a two-arm comparison.

In general, a sample-size calculation asks how much information a hypothetical design might need to detect a specified effect under stated assumptions. It depends on the effect chosen, variability or event frequency, significance level, power target, and design. A planning illustration based on an observed effect is not observed power, and it does not establish that the study was planned with those assumptions. The registry record does not report the study's own sample-size justification. No calculated planning counts or effect estimates are stated in the registry record, so they cannot be interpreted.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variation in count data exceeds what a chosen statistical model expects. If ignored, uncertainty can be understated and confidence intervals may be too narrow. This concept is relevant to some count-outcome analyses, but the primary outcome in this record is a participant response count, and no outcome analysis is reported. The registry does not state that an over-dispersion model was used or needed. It would therefore be inappropriate to attribute a particular count model or adjustment to this study.

More broadly, sound interpretation depends on prespecified outcome definitions, an appropriate denominator, handling of missing assessments, and analysis methods suited to the outcome type. The registry record supplies a CR definition and a timeframe but does not report the analysis details or results needed to evaluate these elements. General statistical principles can clarify what information matters; they cannot replace the missing study-specific methods or findings.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome, complete response rate, and two secondary outcomes, event-free survival and overall survival. Considering multiple outcomes raises a general multiplicity issue: when many hypotheses are tested, the chance of at least one apparently unusual result can increase if each is judged separately without an appropriate plan. Methods to address multiplicity can include a hierarchy of outcomes, adjusted significance thresholds, or a clear distinction between confirmatory and exploratory analyses. The registry record does not report whether any such approach was planned or used.

The record lists zero analyses. It does not report hypothesis tests, confidence intervals, analysis populations, or a statistical analysis plan. Therefore, it is not possible to determine which participants were included in each analysis, whether outcomes were analyzed as planned, or whether any multiplicity adjustment was made.

Missing outcome data can affect interpretation if participants without assessments differ from those with observed outcomes. In general, an analysis should describe missingness and state how it was handled, because excluding participants or making assumptions about unobserved outcomes can change estimates. The registry record does not report the amount or pattern of missing data, reasons for missing assessments, or any missing-data method. This absence does not show that data were complete.

The enrollment figure does not establish the denominator for the primary outcome or the analysis population for survival outcomes. The adverse-event at-risk counts are recorded separately, and their relation to enrollment is not explained. These limitations prevent reconstruction of outcome-specific participant flow or assessment of whether the analysis populations match the intended populations.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: neutropenic fever (16.0%), infection (8.3%), death (5.9%), pneumonia (5.3%), fever (3.6%).

The registry's adverse-event summary gives 169 participants at risk for serious events and 169 at risk for other events. It lists 77 participants affected by serious events, 87 affected by other events, and 10 deaths. These entries describe the posted safety summary; they are not a comparison between randomized groups, because the study is single-group.

The listed serious-event terms and percentages are neutropenic fever (16.0%), infection (8.3%), death (5.9%), pneumonia (5.3%), fever (3.6%), and diarrhea (2.4%). Each percentage should be read as the value recorded for that term, not as a participant-level treatment comparison. The registry record does not report confidence intervals for these values or explain whether participants could appear under more than one term. Event categories can overlap in general, so the listed values should not be added together to estimate an overall rate.

The record also does not explain how seriousness, attribution to treatment, event timing, or duration were assessed. A safety summary can describe reported events, but without a comparator it cannot establish whether event frequencies differ from those under another treatment. The listed deaths are part of the safety information and should not be confused with a reported overall-survival analysis, which is not available in the registry record.

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

The registry record documents a phase 2, single-group study of idarubicin and cytarabine in newly diagnosed AML. It gives a definition and timeframe for the primary endpoint, and identifies EFS and OS as secondary outcomes. It also records adverse-event information. These details describe what the study set out to evaluate and what safety entries were recorded.

The record does not report the CR count or rate, a confidence interval, or numerical EFS and OS results. Consequently, it cannot establish the magnitude or precision of the primary response outcome or characterize survival. A missing result in the registry record is not evidence that the outcome was absent, favorable, unfavorable, or statistically significant. It indicates that the result is not reported in this record.

Even if a single-group response estimate were available, it would describe outcomes among those treated and would not, on its own, establish what would have happened with a different regimen. A comparison requires an appropriate counterfactual, and this record describes no separate comparator. Differences between populations or care settings can also complicate informal comparisons with results from elsewhere.

The safety figures are useful as recorded event summaries, but the record leaves important details unclear, including attribution, overlap among event terms, and the relationship between safety denominators and enrollment. They should not be interpreted as comparative risks or as a complete account of all possible harms. Likewise, the planning illustration described in the record is a hypothetical calculation, not evidence of observed power or a statement of the trial's actual design.

The most defensible conclusion is limited: the registry describes a single-group regimen evaluation with specified outcomes and some safety counts, but does not report the primary efficacy result or the listed survival analyses. Statistical interpretation of efficacy, survival, and comparative safety would require results and methods that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study illustrates why design and reporting must be considered together. A clearly named endpoint and explicit response criteria help readers understand what investigators intended to measure. The CR definition ties the outcome to marrow and peripheral blood findings, and the registry identifies an assessment timeframe. Those features make the endpoint more interpretable than a response label without an operational definition.

At the same time, an endpoint definition is not an endpoint result. Without the observed count, denominator, estimate, and uncertainty, readers cannot assess the response magnitude or precision. Listing EFS and OS similarly does not substitute for reporting their event definitions, follow-up, and analyses. This distinction between outcome specification and outcome reporting is fundamental to evidence appraisal.

The single-group structure also demonstrates the limits of descriptive evidence. Outcomes among treated participants may be informative about the experience recorded in that cohort, but a treatment contrast requires a comparator and a design that supports meaningful comparison. Without those, causal interpretation is constrained. Statistical methods cannot fully repair a design that does not include the comparison needed to answer a comparative question.

Finally, the record contains both an enrollment figure and separate safety at-risk counts, alongside no reported efficacy analyses. This underscores why readers need outcome-specific denominators, analysis populations, and participant flow rather than assuming that one study count applies to every result. A planning illustration should also be kept separate from the actual trial design and observed findings. These distinctions help prevent planning calculations, outcome labels, and safety listings from being mistaken for evidence of efficacy.

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.

Several trial-specific limitations follow from the registry information. First, there is no separate comparator group. The record therefore supports description of a single-group evaluation, not a randomized treatment contrast. Allocation is listed as NA and masking as none. The record does not state whether outcome assessment had other safeguards against bias.

Second, the primary outcome is defined, but its result is not reported. The record does not give the number meeting CR criteria, the denominator, or an uncertainty interval. The secondary outcomes are named without numerical analyses. The registry lists zero analyses, leaving no basis to assess the statistical methods or the results for these outcomes.

Third, details needed to assess applicability and analysis are not reported in the registry record. These include participant characteristics, eligibility criteria beyond newly diagnosed AML, outcome-specific analysis populations, missing-data handling, survival event definitions, follow-up and censoring methods, and the sample-size justification. Their absence limits evaluation but does not show that the study lacked such procedures outside the registry entry.

Finally, the relationship between enrollment of 175 and the safety summary's at-risk counts of 169 is not explained. The registry also does not explain how adverse events were attributed, whether event categories overlap, or how the safety percentages were derived beyond the displayed values. These omissions constrain interpretation of both the safety summaries and the relationship between enrolled participants and those included in safety reporting.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Standard Idarubicin and Cytarabine for the Treatment of Acute Myeloid Leukemia (AML) — NCT00422591.
• Registry record last updated 2018-08-23; status last verified 2018-07.
• Results first posted 2018-06-12.
• 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.

18. Record Summary

The registry describes a completed phase 2, single-group study sponsored by M.D. Anderson Cancer Center, with enrollment of 175. It evaluates idarubicin and cytarabine in patients with newly diagnosed AML. Complete response, assessed up to 2 months, is the primary outcome; event-free survival and overall survival are listed as secondary outcomes.

The CR definition uses marrow and peripheral blood criteria, but the registry record does not report the CR result or numerical survival analyses. The adverse-event summary lists 169 at risk for serious events and 169 at risk for other events, with 77 and 87 affected, respectively, and 10 deaths. A separate comparator, analysis methods, analysis populations, missing-data handling, and the study's sample-size justification are not reported in the registry record.