Combination Chemotherapy and Dasatinib in Treating Participants With Philadelphia Positive or BCR-ABL Positive Acute Lymphoblastic Leukemia.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Combination Chemotherapy and Dasatinib in Treating Participants With Philadelphia Positive or BCR-ABL Positive Acute Lymphoblastic Leukemia. (NCT00390793), a na phase 2 study. The primary outcome is Event-free Survival Rate (EFS).

2. Clinical Question

The clinical question is therefore about outcomes observed after the combination was given to a group of participants, rather than about a treatment difference against a concurrent control. The registry summary presents the combination as a treatment being studied and describes the biological rationale for using chemotherapy with dasatinib. That rationale is not itself evidence of an outcome, and it does not establish how much of an observed outcome would be attributable to any individual drug.

The record lists “Participants With a Response” and “Overall Survival” as secondary outcomes, but does not provide their results in the registry record for this analysis. It also does not describe the response criteria or the exact definition of failure for event-free survival. Those details matter when interpreting outcomes: a time-to-event endpoint depends on both the event definition and the procedures used to follow participants over time.

Because no concurrent comparator is described, outcomes in this group cannot on their own distinguish the effects of treatment from other influences, such as participant characteristics, disease course, or care received during follow-up. The study can describe outcomes among the participants recorded, but the primary result needed to characterize event-free survival is not reported in the registry record.

3. Trial Design

This was a phase II study with a single treatment group. The registry record lists 107 participants as enrolled and describes the treatment group as receiving chemotherapy and dasatinib. Allocation is listed as not applicable, masking as none, and the study model as single group. The record is marked completed, with a start date of 2006-09-28 and primary completion dated 2024-02-02.

A single-group design can describe the outcomes and safety events recorded among participants receiving the regimen. It does not provide a randomized control group for estimating a treatment contrast. The registry record explicitly does not describe a randomized comparison; the treatment group should not be interpreted as a like-for-like comparison with an external group or historical benchmark.

The listed chemotherapy drugs are cyclophosphamide, cytarabine, dexamethasone, doxorubicin, methotrexate, prednisone, and vincristine, alongside dasatinib. The treatment arm description refers readers to a detailed outline, but the treatment schedule and dose details are not reported in the registry record details. Protocol eligibility criteria, treatment modifications, and rules for discontinuing therapy are also not reported in the registry record.

The primary endpoint was event-free survival, measured from treatment start until failure or death from any cause. The record states that 106 of the 107 registered participants were evaluable for this endpoint. It gives a follow-up timeframe of up to 17 years, 4 months, 2 days. It does not state the median event-free survival estimate, its full range, or an accompanying confidence interval.

The registry lists “Participants With a Response” and “Overall Survival” as secondary outcomes. The record does not provide outcome-specific results or analysis details for these endpoints in the registry record for this analysis. Nor does it report the statistical analysis plan, sample-size justification, interim analysis procedures, or how participants who were not evaluable for an outcome were handled. These omissions limit interpretation of the design beyond its single-group structure and stated endpoint definitions.

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: Of the 107 participants registered on study, 106 were evaluable for Event Free Survival.

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 Event-free Survival Rate (EFS), measured over Up to 17 years, 4 months, 2 days.

Event-free survival measures the time from treatment start until the first event included in the endpoint definition. In this study, the registry defines the event as failure or death from any cause. The reported summary measure was intended to be the median, with the full range listed as the dispersion measure. The numerical median and range are not reported in the registry record.

Time-to-event endpoints are useful when the timing of an event matters and participants may have different lengths of follow-up. They can incorporate the time participants remain event-free, rather than reducing follow-up to a simple event/no-event status at one chosen date. In standard time-to-event analysis, participants whose event has not been observed by their last follow-up may be censored: their known event-free time contributes information, while their later outcome remains unknown. The registry entries do not describe censoring procedures or follow-up completeness.

The definition includes death from any cause, so death is counted as an event regardless of its attributed cause. “Failure” is also part of the definition, but the specific criteria for failure are not reported in the registry record. That missing detail makes it difficult to assess exactly which nonfatal events contributed to the endpoint.

The record states that 106 participants were evaluable for event-free survival out of 107 registered. The reason one participant was not evaluable is not reported in the registry record. An endpoint result would ordinarily need to be read alongside its uncertainty and the number of participants whose outcome could be assessed. Neither the numerical median nor a confidence interval is reported in the registry record, so the precision of the primary estimate cannot be assessed from these registry entries.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Event-free survival is a time-to-event outcome: the measured quantity is the time from a defined starting point to the occurrence of an event. Here, the starting point is treatment start and the event is failure or death from any cause. A time-to-event analysis can use information from participants who have different follow-up durations, rather than treating every participant as if observed for an identical period.

What does a median event-free survival estimate represent?

In general, the median event-free survival is the time by which the estimated event-free proportion has reached one half. It is a summary of the distribution of event times, not an average duration for every participant. It does not imply that each participant experienced the event at that time. The registry record identifies the median as the intended summary, but its numerical value is not reported in the registry record. The record also identifies the full range as the dispersion measure, but the range values are not reported in the registry record.

How can censoring affect time-to-event results?

In general, censoring occurs when a participant’s event time is not observed during the available follow-up. For example, a participant may be event-free at the last known contact, after which the event status is unknown. A time-to-event method can use the observed event-free time up to that point without treating the participant as having had an event. The validity of the analysis depends on the censoring process and the method’s assumptions. The registry entries do not specify how censoring was handled, how follow-up was conducted, or whether participants lost to follow-up differed from those with continued observation.

The event definition also matters. “Failure” is not further defined in the registry record, so the range of clinical events included under that term cannot be assessed. Death from any cause is explicitly part of the endpoint. A broader or narrower failure definition could change which events count and when event-free survival is considered to end. The registry does not describe adjudication procedures or whether endpoint events were reviewed independently.

What does a confidence interval add?

In general, a confidence interval conveys the uncertainty around an estimated quantity under the statistical model used. A narrower interval indicates greater precision, while a wider interval indicates less precision; neither by itself resolves possible bias or limitations in the study design. No confidence interval for the primary endpoint is reported in the registry record. Without the median estimate and its uncertainty, readers cannot judge how precisely event-free survival was estimated.

The number evaluable for event-free survival was 106 of the 107 registered participants. The record does not explain why one participant was not evaluable, nor does it state whether the analysis included all registered participants or used another analysis population. The evaluable count indicates the stated denominator for this endpoint, but it does not replace information about event counts, censoring, or completeness of follow-up.

What can a hazard ratio tell readers?

In general, a hazard ratio compares the event rates over time between groups, subject to the model and assumptions used. It is a relative measure, not a direct description of how long participants remained event-free. A hazard ratio requires a comparison group for a treatment contrast. This study is recorded as single group, and no sponsor-reported hazard ratio is present in the registry entries. There is therefore no reported comparative hazard-ratio estimate to interpret. The registry record does not describe a model for any within-group time-to-event analysis.

For a time-to-event analysis, assumptions can include how censoring relates to participants’ underlying event risk and, for some comparative models, whether relative hazards are sufficiently stable over time. Those are general statistical considerations, not claims about the procedures used in this study. The statistical analysis plan and its assumptions are not reported in the registry record, so it is not possible to determine which methods were actually used or how their assumptions were assessed.

How should planning illustrations be understood?

In general, sample-size planning asks how many participants or events would be needed to detect a chosen effect under specified assumptions. It is a forward-looking design exercise, distinct from estimating the result actually observed. Planning assumptions can include a significance level, allocation pattern, statistical approximation, and effect size to detect. The registry entries describe an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of an observed effect.

These are planning assumptions, not a description of the trial’s design. The study itself is single group and has no concurrent two-arm comparison. The registry does not report the trial’s own sample-size justification, so the assumptions for an illustration should not be attributed to the investigators’ design. A planning calculation also does not show that the study had a particular probability of finding a result; it is not observed power. No calculation can supply the missing primary endpoint estimate or its uncertainty.

Finally, the record lists four outcome measures and reports 0 analyses. It does not describe model specification, variance estimation, adjustments, sensitivity analyses, or the handling of missing observations. General explanations of time-to-event methods help clarify what information would be relevant, but they cannot identify the actual statistical procedures used in the absence of a reported analysis plan or results.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists four outcome measures and identifies event-free survival as the primary endpoint. It names “Participants With a Response” and “Overall Survival” among the secondary outcomes. The other outcome-measure details and their numerical results are not reported in the registry record details available for this analysis. The record reports 0 analyses, so there are no analysis estimates or hypothesis-test results to assess for these outcomes.

Multiplicity arises when several outcomes, time points, or statistical tests are examined. In general, conducting multiple tests can increase the chance that at least one result appears noteworthy by chance. Statistical plans may address this through a prespecified hierarchy, adjustment, or interpretation that distinguishes primary from exploratory analyses. The registry record does not report whether any multiplicity strategy was planned or used. It would therefore be inappropriate to assume either that adjustment occurred or that it was unnecessary.

Missing-data handling is also not described. The record states that 106 of 107 registered participants were evaluable for event-free survival, but the reason for the difference and the handling of the participant who was not evaluable are not reported in the registry record. The number evaluable for each secondary outcome is likewise not given in the registry record. The analysis population for response and overall survival is not reported.

The record does not describe an intention-to-treat population, a per-protocol population, rules for censoring, or methods for handling missing outcome information. These details affect how results should be interpreted and how sensitive they may be to incomplete follow-up. Without a statistical analysis plan and outcome-level analysis populations, the reader cannot determine how participants were selected for each analysis or whether missingness could have influenced the reported estimates.

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

Serious events with the highest arm-level rate: neutropenic fever (12.1%), pleural effusion (10.3%), fever (7.5%), pneumonia (4.7%), diarrhea (3.7%).

For the treatment group, 107 participants were listed as at risk for serious adverse events and 38 as having serious adverse events judged related to the treatment. The record also lists 107 participants at risk for other adverse events and 0 with other adverse events judged related. These are registry safety counts; they should be read in the context of the recorded group and the record’s classification of relatedness.

The most frequently listed serious adverse event terms include neutropenic fever at 12.1%, pleural effusion at 10.3%, fever at 7.5%, pneumonia at 4.7%, diarrhea at 3.7%, and nausea/vomiting at 3.7%. These percentages are reported as listed and should not be treated as event counts. The registry entries do not give counts for each term, and they do not explain whether participants could contribute more than one event or appear under more than one term.

The record lists 4 deaths, but the registry entries do not report whether those deaths were attributed to treatment, the disease, or another cause. A death count is not equivalent to a count of treatment-related deaths. Similarly, an adverse event being recorded as related is a classification in the registry; it does not establish causality in the way a randomized comparison might help assess differences between groups.

Because there is no control group, these safety figures describe reports in the treated cohort and cannot quantify a comparative excess or reduction in risk. The registry entries also do not provide the exposure duration or detailed methods for collecting and classifying adverse events. The figures should therefore be interpreted as descriptive safety reporting, not as a controlled estimate of treatment-attributable risk.

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

The registry record documents a phase II, single-group study of chemotherapy combined with dasatinib in participants with Philadelphia-positive and/or BCR-ABL-positive acute lymphoblastic leukemia. It identifies event-free survival as the primary endpoint and defines it as time from treatment start until failure or death from any cause. It also records that 106 of 107 participants were evaluable for that endpoint and gives a follow-up timeframe of up to 17 years, 4 months, 2 days.

Those details describe the study and its intended measurement; they do not supply the primary outcome result. The median event-free survival, the full range, and a confidence interval are not reported in the registry record. The record also does not report numerical results for the secondary outcomes of response and overall survival. Consequently, no conclusion about the size or precision of these outcomes can be drawn from the registry entries.

The single-group design has an important interpretive consequence. Outcomes can be described for the cohort, but there is no randomized concurrent comparator in the registry record. A result from this design would not, by itself, establish what would have happened to comparable participants under another treatment. Nor could it isolate the contribution of dasatinib from the contributions of the chemotherapy drugs or other aspects of care.

The safety entries describe serious adverse events judged related to treatment in 38 of 107 participants, no other adverse events judged related in 0 of 107, and 4 deaths. The record does not report attribution for the deaths in the registry record. These numbers should not be converted into comparative claims about safety, because no control group is available and the record does not provide all details about exposure or event ascertainment.

Thus, the registry entries establish the study’s design, treatment components, endpoint definition, evaluable count, and selected safety reports. They do not establish a comparative treatment effect, the primary endpoint’s numerical result, or the statistical certainty of that result. Those distinctions are essential when separating what a trial record documents from what it can support as an inference.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why design and result reporting must be read together. The study has a clearly identified time-to-event primary endpoint and a stated endpoint definition, but the registry entries do not report the median estimate or its uncertainty. A well-defined outcome is necessary for interpretation, yet it cannot substitute for the numerical result.

The single-group design also clarifies the boundary between describing outcomes and estimating comparative effects. A cohort’s event-free survival and safety reports can be useful descriptive information. Without a concurrent control group, however, those observations do not determine how outcomes would differ under another treatment. This is a design limitation for causal comparison, not a computational issue that can be repaired by adding a statistical model to the same data.

The difference between the 107 registered participants and the 106 evaluable for event-free survival makes analysis-population reporting relevant. The record does not explain why one participant was not evaluable, or how missing information was handled. Even a small difference in evaluability should be interpreted through the reasons and analysis rules, which are not reported in the registry record.

The safety data illustrate another statistical distinction: a count of events judged related within a treated group is not the same as an estimate of excess risk attributable to treatment. Attribution, event collection, follow-up time, and a comparator all affect what can be inferred. The registry lists serious event terms and percentages, but does not provide a controlled contrast.

Finally, planning assumptions should not be confused with study design or observed evidence. The described sample-size illustration uses assumptions for a two-arm calculation, whereas the registered trial is single group. A planning exercise is not observed power and does not fill the gap left by unreported endpoint results. Together, these points make the record useful for teaching the limits of interpretation when outcome estimates, analysis methods, and comparison groups are 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 main limitation for interpreting efficacy is that the registry entries do not report the primary endpoint estimate. Although the outcome is described as median event-free survival with full range, neither the median nor the range values are available in the registry record. No confidence interval is reported, so precision cannot be assessed. The same details do not give numerical results for the listed secondary outcomes.

The study is single group, with no randomized comparator. It can therefore describe the outcomes recorded among participants receiving the combination but cannot provide a randomized estimate of the treatment contrast against another regimen. External comparisons would be vulnerable to differences in participant selection, disease features, follow-up, endpoint definitions, and care, and no such comparison is reported in the registry record.

The endpoint definition includes “failure,” but the criteria for failure are not given in the registry record. Without those criteria, the exact events contributing to event-free survival are unclear. The registry also does not explain censoring rules, follow-up completeness, or how the participant not evaluable for event-free survival was handled. The reason for that non-evaluability is not reported in the registry record.

The registry entries do not state the statistical analysis plan, sample-size justification, interim analysis procedures, or multiplicity strategy. They do not provide an analysis population for the secondary outcomes, nor the detailed methods for response assessment. The record lists 0 analyses, limiting the available estimates and methodological detail.

Safety interpretation is also constrained. The record gives counts and selected serious adverse event percentages but does not provide event-specific counts in the registry record, exposure duration, or attribution for the 4 deaths. With no comparator, the reported safety figures are descriptive and do not quantify a comparative treatment-related risk.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Combination Chemotherapy and Dasatinib in Treating Participants With Philadelphia Positive or BCR-ABL Positive Acute Lymphoblastic Leukemia. — NCT00390793.
• Registry record last updated 2025-02-17; status last verified 2025-01.
• Results first posted 2025-02-17.
• 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

NCT00390793 is a completed phase II, single-group study of combination chemotherapy and dasatinib in participants with Philadelphia-positive and/or BCR-ABL-positive acute lymphoblastic leukemia. The sponsor is M.D. Anderson Cancer Center. The registry lists 107 participants enrolled, with a start date of 2006-09-28 and primary completion dated 2024-02-02.

The primary endpoint is median event-free survival, defined from treatment start to failure or death from any cause. The record states that 106 participants were evaluable for this endpoint and describes follow-up up to 17 years, 4 months, 2 days. The median result and its uncertainty are not reported in the registry record.

Secondary outcomes listed are participants with a response and overall survival. The safety record lists 38 participants with serious adverse events judged related to treatment, 0 with other adverse events judged related, and 4 deaths. The study has no randomized comparator, and the registry entries report 0 analyses.