Phase II Study of Decitabine and Cytarabine for Older Patients With Newly Diagnosed Acute Myeloid Leukemia (AML): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Phase II Study of Decitabine and Cytarabine for Older Patients With Newly Diagnosed Acute Myeloid Leukemia (AML) (NCT01829503), a na phase 2 study. The primary outcome is Number of Participants by Best Clinical Response Experienced.

2. Clinical Question

3. Trial Design

This is a phase II, completed, single-group study of an induction regimen for older patients with newly diagnosed AML. The registry record lists enrollment of 44. It gives a start date of 2013-02 and a primary completion date of 2015-10. Allocation is listed as NA, masking as none, and the study model as single group. These features mean the record describes outcomes after treatment, rather than a randomized comparison between treatment groups.

The regimen is described as decitabine followed by cytarabine. Decitabine is listed at 20mg/m2 in normal saline intravenously over 1 hour daily for five days. Cytarabine is listed at 100mg/m2 in normal saline as a continuous intravenous infusion over 24 hours for 5 days. Treatment was to be delivered through an inpatient leukemia service. The record also lists supportive care as an intervention but does not provide a separate arm description for it.

The primary objective is to determine efficacy, with complete remission rates as the primary endpoint. The registry's primary outcome describes numbers of participants by best clinical response and specifies a timeframe of up to 38 months. Secondary objectives include assessment of safety, survival, and potential predictive factors. Listed secondary outcomes include adverse events, survival at specified time points, overall survival, and relapse-free survival.

The record does not report a randomized control group, a masking procedure, or a separate arm-level description for supportive care. It also does not report the protocol's statistical analysis plan or a sample-size justification. The enrollment figure is not itself the number evaluable for the primary outcome; the registry describes that population as participants with known clinical response, but does not give its size.

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

Analysis population for the primary outcome, as defined in the registry: Evaluable participants with known Clinical Response.

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: Number of participants with each of the observed demographic and clinical characteristics.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants by Best Clinical Response Experienced, measured over Up to 38 months.

The primary outcome is the number of participants classified by their best clinical response, with the registry describing complete response, complete response with incomplete count recovery, partial response, and progressive disease. The brief description names complete remission rates as the primary endpoint. These measures address whether participants met response categories during treatment follow-up; they are not, by themselves, a comparison of this regimen with another treatment.

The record defines complete response as less than 5% blasts in a bone marrow aspirate together with an absolute neutrophil count >1000µ/L and platelets >100,000µ/L. Complete response with incomplete count recovery is described as meeting the complete-response criteria except for residual neutropenia (<1000µ/L) or thrombocytopenia (<100,000µ/L). Partial response is defined as a decrease of at least 50% in the percentage of blasts to 5-25% in the bone marrow aspirate. Progressive disease is defined as failure to achieve complete response or partial response.

Response categories are clinically interpretable summaries of disease status, while the registry's count format reports how many participants fell into each category. The number of participants in each category, and the number evaluable with known clinical response, are not reported in the registry record. Without those counts, the posted record does not establish the observed complete-response frequency or how precisely it was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies this as a phase II, single-group study with no masking. The primary outcome is a count of participants classified by best clinical response. This is a descriptive outcome: it organizes observed participants into defined categories. It does not, by itself, estimate a difference between treatment groups. Since allocation is listed as NA and the model is single group, there is no randomized comparison described in the record.

What does a response category measure?

A response category applies clinical criteria to participant-level assessments. The registry gives definitions for complete response, complete response with incomplete count recovery, partial response, and progressive disease. The category called “best” response refers to the most favorable qualifying category experienced during the stated outcome period, according to the registry's endpoint description. The registry does not report the assessment schedule or additional rules for determining best response. The category definitions help clarify what is counted, but do not reveal how many participants met each definition.

The primary endpoint is described as complete remission rates in the study summary, while the registry outcome is titled as a number of participants by best clinical response. These descriptions are related but not identical in presentation: the summary names remission as the primary endpoint, and the outcome description lists several response categories. The record does not provide category counts or a remission rate. No rate should be inferred from enrollment alone.

How should uncertainty be assessed?

General statistical explanation: an estimate describes a pattern in the observed study population, while a confidence interval conveys the precision of that estimate under the assumptions of the analysis. Wider intervals indicate less precision, and narrower intervals indicate greater precision. A confidence interval does not remove limitations from a single-group design or make an uncontrolled result comparable to a randomized treatment contrast. The registry record does not report a confidence interval for the primary outcome, so its statistical precision cannot be assessed from the posted results.

A hypothesis test, when used, evaluates data against a specified statistical model and null hypothesis. A p-value is not a measure of the size or clinical importance of an effect. The registry information does not report a p-value or a hypothesis test for the primary response outcome. It also does not report the analysis plan that would identify any prespecified test or model. No inferential result should be reconstructed from outcome definitions alone.

What does the planning illustration represent?

General statistical explanation: sample-size planning asks how much information a future study might need to detect a target effect under stated assumptions. The posted planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; they describe detecting a stated fraction of an observed effect. For time-to-event outcomes, the illustration is based on a total event count, while other illustrations are expressed as participants per arm for 80% power or another stated power level. Such values are planning illustrations, not observed power and not the design justification for this single-group study.

The hypothetical equal-allocation comparison in a planning illustration does not change the actual study design. This trial is not a randomized comparison, and its registry record does not describe like-for-like control arms. The record does not report its own sample-size justification, so the planning illustration cannot be treated as evidence that the trial was designed to achieve a particular power for its primary outcome.

Why does the analysis population matter?

The registry describes the primary population as evaluable participants with known clinical response, whereas enrollment is 44. In general, an analysis population specifies which participants contribute to an outcome estimate. Different rules for handling missing assessments can affect the number classified and the resulting estimate. The registry record does not state the size of the evaluable population, how missing response assessments were handled, or whether any alternative analysis population was used.

Over-dispersion is a general concern when count data vary more than a chosen statistical model expects; if present and ignored, uncertainty may be understated. The primary outcome is a count by response category, but no fitted model or dispersion estimate is reported. It is not possible to determine whether an over-dispersion adjustment was relevant or used. More broadly, the statistical plan, model assumptions, and analysis details are not reported in the registry record. The outcome definitions and study structure can be described, but the missing analysis details prevent a fuller assessment of model-based inference.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and multiple secondary outcomes, including adverse events, survival at specified time points, overall survival in several response-defined groups, relapse-free survival, and potential predictors of overall survival. When several outcomes or subgroup analyses are examined, the chance of at least one apparently notable result can increase. General statistical practice may address this multiplicity by prespecifying a hierarchy, adjustment, or interpretation strategy. The registry record does not report whether any multiplicity strategy was planned or used, so the secondary outcomes should not be treated as confirmatory findings on the basis of their listing alone.

Missing-data handling is also not reported. The primary population is described as evaluable participants with known clinical response, but the number in that population and the reasons any enrolled participants may not have had a known response are not stated. The registry does not specify whether missing responses were excluded, treated as nonresponse, or handled by another method. Each approach can affect a response summary, so the outcome counts and analysis rules are needed to interpret it.

The record does not report the protocol's analysis populations, interim-analysis plan, or statistical analysis plan. It is therefore not possible to determine from the registry record whether the listed outcomes and analyses were prespecified in detail, or how departures from any plan were handled. These omissions do not show that a particular method was or was not used; they mean that the method is not reported in the registry record.

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: febrile neutropenia (11.4%), anemia (6.8%), white blood cell decreased (6.8%), death nos (4.5%), fever (4.5%).

The registry reports serious adverse events for the Decitabine + Cytarabine group: 30 participants were affected among 44 at risk. It reports other adverse events affecting 43 participants among 44 at risk. These are participant counts, not a comparison with an untreated or control group. The record also lists serious-event terms with percentages: febrile neutropenia, 11.4%; anemia, 6.8%; white blood cell decreased, 6.8%; Death NOS, 4.5%; fever, 4.5%; and creatinine increased, 4.5%.

The registry does not explain in this record whether each term percentage represents participants or events, or provide details needed to interpret overlap among terms. A participant may experience more than one event, so term counts should not be added to estimate a total. The serious-event summaries should also not be equated with the separate secondary outcome for adverse events meeting CTCAE grade thresholds; the grade-specific results are not reported in the record. These data describe the reported safety outcomes and do not establish a comparative safety effect.

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

The registry record establishes that a completed phase II study evaluated decitabine followed by cytarabine in older patients with newly diagnosed AML. It describes a single-group, unmasked design, enrollment of 44, a primary response outcome, and several secondary safety and survival outcomes. It also provides definitions for response categories and selected adverse-event summaries. These details clarify what the study set out to assess and how some outcomes were defined.

The record does not report the primary response counts or the number evaluable for known clinical response. Therefore, it does not permit calculation or interpretation of an observed complete-response rate from the posted information. Nor does it provide confidence intervals or a reported statistical test for the primary outcome. The record's enrollment figure cannot substitute for the missing outcome data.

Even with complete response counts, this single-group design would describe outcomes among treated participants rather than establish how those outcomes compare with another treatment. There is no randomized control group in the registry record. Thus, the reported design cannot separate regimen-related effects from other influences on outcomes or establish a causal treatment contrast.

The safety information indicates that serious adverse events and other adverse events were reported, and names several serious-event terms. It does not give the full context needed to compare safety across treatments, and the grade-specific outcome results are not reported. The listed survival and relapse-free survival outcomes also cannot be interpreted without their estimates, follow-up details, and analysis results.

In short, the registry record is informative about study structure, endpoint definitions, and selected safety summaries. It does not provide enough outcome reporting to quantify the primary response result or determine its precision, and it does not support conclusions about comparative efficacy or safety.

13. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and study design need to be read together. The registry describes a clinically defined response outcome with several categories, but the outcome counts are not reported. Without those counts, readers cannot see the observed response distribution or assess the precision of a response estimate. Clear definitions make an endpoint interpretable; they do not replace reporting the data used to summarize it.

The single-group design also sets an important boundary on interpretation. Response and safety outcomes can describe what was observed among participants receiving the regimen, but the record contains no randomized comparison to distinguish treatment effects from other explanations. A reader should not turn a within-study outcome into a comparative claim when no control group is reported.

The record further shows why enrollment and analysis populations should be distinguished. Although enrollment is 44, the primary outcome is defined for evaluable participants with known clinical response, and that population's size is not stated. Reporting the number assessed, the handling of missing outcomes, and the analysis rules would help readers understand which participants contribute to the result.

Finally, the breadth of listed secondary outcomes makes transparent prespecification and multiplicity handling important. The registry record does not report those methods. Statistical interpretation depends not only on the endpoint name, but also on the analysis plan, uncertainty estimates, and completeness of outcome reporting. This record offers useful design and definition information while leaving those key inferential details unavailable.

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 central limitation for interpreting efficacy is that the registry record does not report counts for the primary response categories. It also does not state how many of the 44 enrolled participants were evaluable with known clinical response. As a result, the observed response distribution and its precision cannot be assessed from the posted results.

The single-group, unmasked design has no like-for-like control comparison. Any observed outcomes would describe participants treated within the study, not a randomized estimate of the regimen's effect relative to another treatment. The registry record does not report blinded response assessment.

The record describes the primary outcome timeframe as up to 38 months, but does not give the response assessment schedule or report how complete follow-up was for the endpoint. It also does not report the missing-data rules, analysis populations, statistical analysis plan, or sample-size justification. These gaps limit evaluation of the response analysis and the assumptions behind any inferential claims.

Although several secondary outcomes are listed, their results and analysis details are not reported in the registry record. Safety information includes participant counts and selected serious-event terms, but the term-level denominator and overlap are not explained. Grade-specific adverse-event results are not reported in the information available for interpretation. These limitations are specific to the record and should not be mistaken for proof that an analysis or assessment was not performed.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Phase II Study of Decitabine and Cytarabine for Older Patients With Newly Diagnosed Acute Myeloid Leukemia (AML) — NCT01829503.
• Registry record last updated 2019-11-14; status last verified 2019-11.
• Results first posted 2017-09-14.
• 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 II, single-group, unmasked study of decitabine followed by cytarabine for older patients with newly diagnosed AML. Enrollment was 44; the record gives a start date of 2013-02 and a primary completion date of 2015-10. The primary outcome is best clinical response, with complete response, complete response with incomplete count recovery, partial response, and progressive disease as categories.

The registry record does not report the primary response counts or the number evaluable for known response. It reports serious adverse events affecting 30 participants among 44 at risk and other adverse events affecting 43 participants among 44 at risk, alongside selected serious-event terms and percentages. A comparator group, detailed statistical analysis plan, missing-data method, and multiplicity strategy are not reported in the registry record.