Decitabine Followed by Idarubicin and Cytarabine in Treating Patients With Relapsed or Refractory AML and MDS: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Decitabine Followed by Idarubicin and Cytarabine in Treating Patients With Relapsed or Refractory AML and MDS (NCT01607645), a randomized phase 2 study. The primary outcome is Number of Participants Who Achieved Morphologic CR.

2. Clinical Question

The study was designed to examine whether changing the timing of decitabine priming, and thus the interval before idarubicin and cytarabine, might affect treatment effectiveness or side effects. It also listed identifying factors that might predict response as a goal. The registry record does not describe the factors evaluated or report results for that goal.

This is a comparison of schedules, not a comparison of the three-drug combination against no treatment or against a different combination. Both arms included decitabine, idarubicin, and cytarabine. The principal contrast is the earlier versus later decitabine schedule, while the subsequent chemotherapy schedule was shared. The record identifies the study population broadly through a list of AML subtypes and MDS-related conditions; further eligibility details are not reported in the registry record.

3. Trial Design

The registry record identifies this as a randomized, open-label, parallel phase II trial sponsored by Fred Hutchinson Cancer Center. Participants were allocated to one of two treatment schedules. Randomization can help balance participant characteristics between groups over repeated trials, but with enrollment of 7 participants, the groups in this trial were small: 4 participants were in Arm I and 3 in Arm II. The record does not report the randomization method or details of allocation concealment.

The arms used the same three drugs but scheduled decitabine differently. Arm I received decitabine intravenously over 1 hour on days -4 to 0. Arm II received it intravenously over 1 hour on days -9 to -5. In both arms, cytarabine was given intravenously continuously over 24 hours on days 1-7, and idarubicin was given intravenously over 10-15 minutes on days 1-3. The record therefore frames the comparison around the timing of decitabine priming, not a change in the listed drugs or the later idarubicin and cytarabine schedule.

Because masking was none, the trial was open-label: the treatment assignment was not masked according to the registry. Whether outcome assessors were separately blinded is not reported in the registry record. The study status is terminated. Its recorded start is 2012-07, and its primary completion is 2013-07. The reason for termination and the circumstances leading to the recorded enrollment are not reported in the registry record.

The listed primary outcome was the number of participants who achieved morphologic CR, monitored until participants went off study following treatment completion, with the timeframe stated as 3 months. The registry lists 13 outcome measures overall, including response categories and safety outcomes. It reports no analyses. Protocol details such as planned statistical models, sample-size justification, interim analyses, and analysis populations are 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

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 Who Achieved Morphologic CR, measured over Participants were monitored up until the point when they went off study following completion of the treatment (3 months).

The primary endpoint is the number of participants who achieved morphologic complete remission (CR). It is a count endpoint: it asks how many participants met the stated remission criteria, rather than measuring a continuous quantity such as a laboratory value or the time until an event. The registry says participants were monitored until they went off study following completion of treatment, with a timeframe of 3 months.

The registry defines morphologic CR using blood and bone marrow findings. The criteria include an absolute neutrophil count of at least 1,000/uL, a platelet count of at least 100,000/uL, fewer than 5% bone marrow blasts, no Auer rods, no morphologic dysplasia, and no evidence of extramedullary disease. These criteria combine blood-count recovery with disease assessment. A count of participants meeting the full definition gives a direct summary of how many reached the specified response state during the stated follow-up.

Such a response endpoint can be useful in a phase II study because it captures a clinically interpretable treatment outcome rather than only a change in a single measurement. However, the registry record does not report the count of participants who achieved morphologic CR in either arm. It also does not report an effect estimate or uncertainty interval for this endpoint. Consequently, the endpoint definition is available, but the posted record does not establish how often the defined response occurred or how the schedules compared.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the randomized comparison estimate?

In general, a randomized parallel trial compares outcomes between groups assigned to different treatment strategies. In this trial, the strategies share idarubicin and cytarabine and differ in the timing of decitabine. The target contrast is therefore between the two schedules as assigned, not between receiving and not receiving the three-drug regimen. A treatment effect could be expressed in several ways for a binary outcome, including a difference in the proportion with the outcome or a relative measure. The registry record does not report an effect estimate for morphologic CR, so no such numerical contrast can be interpreted.

Random assignment is intended to reduce systematic differences in prognostic factors between groups. In general, it does not ensure balance in every realized trial, especially when group sizes are small. The record confirms randomization but does not describe its method, any stratification, or the balance of participant characteristics. It also does not report an adjusted or unadjusted model.

What does a count endpoint mean?

The primary outcome is a number of participants achieving morphologic CR, which is a count of participants meeting a binary definition: each participant either meets the listed criteria during the specified follow-up or does not. To interpret that count as a rate, the number at risk or assessed in each arm must also be known. The record gives arm enrollment but does not give primary outcome counts. It therefore does not permit calculation or interpretation of arm-specific response proportions from the posted record.

For binary outcomes, uncertainty depends on both the observed event count and the number of participants assessed. A confidence interval, in general, represents a range of estimates compatible with the data under a specified method; it is not a guarantee that the true effect lies in that range. No confidence interval for morphologic CR is reported. With a small total enrollment, estimates based on only a few outcomes would generally be imprecise, but the extent of imprecision cannot be assessed without the outcome counts and a specified analysis.

What can be learned from the listed safety counts?

The safety record gives the number of participants at risk and the number affected by serious and other adverse events in each arm. These are descriptive counts. In general, a count of participants with at least one event differs from a count of all events: one participant can experience multiple events, while a participant-level count records that person once in the relevant category. The registry does not provide enough event-level detail to reconstruct the number, timing, or pattern of all adverse events.

The serious-event counts are 0 of 4 in Arm I and 1 of 3 in Arm II. The other-event counts are 4 of 4 and 2 of 3, respectively. Those counts should not be treated as a formal statistical test or as a precise estimate of comparative safety. No confidence intervals, p-values, adjusted analyses, or exposure-adjusted rates are reported. In general, comparisons of event counts can be affected by follow-up duration and the way events are collected; further details are not reported in the registry record.

How should planning calculations be understood?

In general, a sample-size planning illustration asks how many participants might be needed to detect a chosen effect under stated assumptions. It is a prospective design scenario, not a measure of the probability that a completed study found a real effect. A calculation based on an observed effect can illustrate how the required sample size changes if the effect to detect is smaller than the observed estimate. Such illustrations depend on assumptions about the significance level, allocation, statistical approximation, and target effect.

The registry record does not report the trial's own sample-size justification or a protocol-based target enrollment. Any planning illustration must therefore be distinguished from the trial design as actually documented. It is not observed power, and it does not resolve the lack of a reported primary outcome. A planning number cannot recover missing results or establish that a treatment comparison was adequately powered.

What statistical analysis is documented?

The registry reports no analyses. It does not identify an analysis population, model, handling of missing outcomes, multiplicity procedure, or interim analysis. None should be inferred from the fact that the trial was randomized or phase II. The endpoint definition and study design can be described, but the analysis choices and efficacy estimates needed for a quantitative interpretation are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures, including the primary morphologic CR endpoint and multiple secondary response and safety outcomes. When a study assesses several outcomes, categories, or time points, the chance of observing an apparently notable result by chance can increase if many comparisons are examined. In general, multiplicity procedures may control that risk, but the choice of procedure depends on the planned testing strategy. The registry record does not report a multiplicity plan, a hierarchy among secondary outcomes, or which comparisons were treated as confirmatory.

The registry record indicates that the primary outcome has several categories or time points and is not reduced to one comparison. It does not provide a single primary comparison result. The record also reports no analyses, so there are no reported tests or estimates to assess in light of multiplicity.

Handling of missing data is not reported in the registry record. It does not state whether all enrolled participants were included in the primary analysis, how participants who left the study were treated, or whether missing endpoint assessments were imputed or excluded. The primary outcome timeframe says participants were monitored until going off study after treatment completion, but that does not specify how incomplete follow-up was handled analytically. Analysis populations, such as an intention-to-treat population or a per-protocol population, are also not reported.

These omissions limit reproducibility and interpretation. Without a prespecified analysis description, outcome counts, and information on missingness, readers cannot determine whether all randomized participants contributed to each outcome or whether the comparison followed a particular analysis plan. These details should not be guessed from the trial's randomized design.

11. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: grade 4 infection (33.3%).

The registry lists serious adverse-event counts by arm, with the number at risk alongside the number affected. Arm I had 0 of 4 participants with serious adverse events listed, and Arm II had 1 of 3. For other adverse events, it lists 4 of 4 participants in Arm I and 2 of 3 in Arm II. These figures describe participants affected in the registry's categories; they do not provide the total number of individual event episodes or their timing.

The record also identifies Grade 4 Infection at 33.3% among the top serious adverse-event terms. The denominator, event details, and any relationship to treatment are not reported in the registry record. The listed term does not by itself describe all infections or the full safety profile.

Deaths are not reported. The record does not provide exposure-adjusted rates, confidence intervals, or a formal between-arm safety analysis. Given the small enrolled groups, the counts are descriptive and do not establish a reliable comparative estimate. They should be read separately from the primary remission endpoint, whose results are not reported.

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

The registry record establishes that a randomized phase II study compared two decitabine-priming schedules before the same idarubicin and cytarabine schedule in adults with relapsed or refractory AML or MDS. It documents enrollment of 7 participants and identifies morphologic CR as the primary outcome. It also gives participant counts for serious and other adverse events. These details clarify what was studied and provide a limited descriptive account of safety.

The record does not report how many participants achieved morphologic CR in either arm. It also does not provide a treatment-effect estimate, confidence interval, p-value, or reported analysis. As a result, the registry information cannot show how often remission occurred, whether the observed response differed between schedules, or how precise a comparison would be. The absence of a result in the registry record is not evidence that no participants achieved remission, and it does not establish that the schedules had identical outcomes.

The safety counts likewise do not establish that one schedule is safer than the other. They are small participant counts, without event-level descriptions, exposure-adjusted analyses, or reported uncertainty. The record does not explain why the trial was terminated, so the status should not be interpreted as proof of a particular benefit, harm, or operational problem.

In general, a randomized design helps organize a fair comparison, but the usefulness of its results depends on outcome reporting, analysis details, and adequate precision. Here, the design and endpoint are described more fully than the primary result and analysis. The registry record therefore supports a description of the trial and its reported adverse-event counts, but not a conclusion about comparative efficacy or a definitive safety difference.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of the distinction between a clearly described design and a fully interpretable result. The record identifies randomization, parallel groups, the two treatment schedules, and a defined primary outcome. Those features make the intended comparison understandable: the timing of decitabine priming differs, while idarubicin and cytarabine are given on the same later schedule in both arms.

At the same time, enrollment was 7, and the primary remission counts are not reported. This combination illustrates why statistical interpretation depends not only on a study's design but also on complete outcome reporting. A randomized comparison can reduce some sources of bias in principle, yet it cannot yield a verifiable treatment-effect estimate when the outcomes and analysis are absent from the record.

The adverse-event counts also show why descriptive data should not be mistaken for a precise comparative analysis. Counts can be useful for transparency and for indicating what was recorded, but small groups and limited event detail restrict interpretation. The listed serious-event category and the separate count of other adverse events answer different descriptive questions and do not fill the gap in the primary efficacy result.

Finally, a phase II designation and an endpoint with a clinical definition do not establish that the trial met a particular statistical objective. The registry does not report a sample-size justification, statistical analysis plan, or analyses. This record therefore highlights a practical lesson for clinical research: reporting the estimand, outcome counts, uncertainty, analysis population, and handling of missing data is essential for readers to understand what a trial can support.

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 trial's small enrollment is a central limitation for interpreting the posted counts. The registry reports 7 participants, divided between groups of 4 and 3. With so few participants, descriptive event counts contain little information about the range of outcomes that might occur in a broader population. No primary outcome counts or uncertainty estimates are reported, so the precision of a remission comparison cannot be assessed.

The registry identifies the study as terminated but does not report why it was terminated. It also does not report whether the planned enrollment was reached, whether recruitment ended as intended, or whether all participants completed follow-up. The stated primary outcome timeframe is 3 months, but completeness of outcome ascertainment is not described.

The trial was open-label, and separate blinding of outcome assessment is not reported. The registry does not report the randomization procedure, baseline characteristics, analysis populations, missing-data approach, or statistical methods. Those omissions prevent assessment of whether the groups were comparable at baseline and how the reported outcomes were analyzed.

Only limited aggregate safety information is available. The number of participants affected is listed, but event-level details and deaths are not reported. The registry also lists a Grade 4 Infection term at 33.3% without reporting its denominator or further context. The reason for this figure and its relationship to the overall safety counts cannot be determined from the record.

Finally, the primary endpoint is not reduced to one reported comparison, and the record gives no inferential analyses among the 13 listed outcomes. The missing analysis plan and outcome results limit both reproducibility and conclusions about efficacy or comparative safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Decitabine Followed by Idarubicin and Cytarabine in Treating Patients With Relapsed or Refractory AML and MDS — NCT01607645.
• Registry record last updated 2017-03-31; status last verified 2017-02.
• Results first posted 2017-03-31.
• 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

NCT01607645 is a randomized, open-label, parallel phase II trial of decitabine followed by idarubicin and cytarabine in relapsed or refractory AML and MDS. The two arms used different decitabine schedules before the same listed idarubicin and cytarabine schedule. The registry reports enrollment of 7 participants: 4 in Arm I and 3 in Arm II. The trial is recorded as terminated.

The primary outcome was the number of participants achieving morphologic CR, with monitoring through treatment completion and a stated timeframe of 3 months. The registry record does not report the primary outcome counts or any analyses. It lists 13 outcome measures and reports serious adverse events in 0 of 4 participants in Arm I and 1 of 3 in Arm II, and other adverse events in 4 of 4 and 2 of 3, respectively. The record does not report deaths, the reason for termination, or the statistical analysis plan.