Dasatinib in Treating Patients With Chronic Lymphocytic Leukemia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dasatinib in Treating Patients With Chronic Lymphocytic Leukemia (NCT01441882), a na phase 2 study. The primary outcome is The Number of Participants With In Vitro Dasatinib Sensitivity in Predicting Clinical Activity.

2. Clinical Question

In statistical terms, the study asks whether clinical activity, defined by changes in disease measurements, was observed among patients studied in this single treatment group. It is not designed in the registry record as a comparative-effectiveness question. Without a control group, the study cannot separate changes occurring during treatment from changes that might have occurred over the same period for other reasons. The record describes the planned clinical question and endpoint definition, but does not report the results needed to answer how many participants met the endpoint.

3. Trial Design

This was a phase II clinical trial of dasatinib in patients with chronic lymphocytic leukemia. The registry records a single-group model, no masking, and allocation as not applicable. Enrollment is listed as 19, and the study status is completed. The sponsor is OHSU Knight Cancer Institute. The recorded start is 2011-10 and primary completion is 2016-07-12.

The treatment description specifies oral dasatinib once daily during course 1, followed by twice-daily dosing in subsequent courses if tolerated. Courses were to repeat every 4 weeks while there was no disease progression or unacceptable toxicity. Laboratory biomarker analysis and a pharmacological study are also listed as interventions. Their detailed procedures and how their results informed the primary analysis are not reported in the registry record.

The registry lists objective response, overall survival, progression-free survival, and incidence of adverse events as secondary outcomes. It records 5 outcome measures and 3 analyses, but the detailed definitions and analysis methods for these measures are not reported in the registry record. The primary endpoint is described as a participant count at 8 weeks, using changes in lymphocyte count, bone marrow findings, lymph node size, or spleen size.

Because there was no comparison arm and the study was not masked, its design supports descriptive interpretation of outcomes in the treated group, rather than a direct estimate of the difference between dasatinib and an alternative. The record does not report a protocol-level statistical analysis plan, eligibility details beyond the disease and sensitivity framing, or a description of the analysis population. These omissions limit what can be concluded about how participants were selected, how measurements were handled, and how the registered questions were ultimately evaluated.

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 The Number of Participants With In Vitro Dasatinib Sensitivity in Predicting Clinical Activity, measured over 8 weeks.

The primary endpoint is a count of participants with clinical activity at 8 weeks, under a definition based on changes in disease measurements. The registry specifies a decrease of 50% in absolute lymphocyte count, determined by peripheral blood complete blood count with differential or by bone marrow examination, and/or a decrease of 50% in detectable total lymph node size or spleen size, measured by clinical examination or contrast-enhanced computed tomography. The endpoint title connects this count with the question of whether in vitro dasatinib sensitivity predicts clinical activity.

A participant count is a binary-outcome summary: each participant either meets the stated endpoint definition or does not. In general, such an endpoint can make a complex clinical response easier to describe as a clear event, but that simplification depends on the measurement rules being applied consistently. This definition combines more than one possible indicator of change, including blood or marrow findings and lymph node or spleen size. The record does not explain how conflicting measurements were resolved, how missing measurements were treated, or whether confirmation was required.

The endpoint is useful for organizing an early-phase study around a specified observation period and measurable signs of disease change. It does not, by itself, establish that a change was caused by treatment, nor does it provide a comparative estimate when there is no control group. Most importantly, although the endpoint and timeframe are described, the number of participants who met the definition is not reported in the registry record. The extent of clinical activity therefore cannot be assessed from the primary endpoint result in the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary measure as a count of participants meeting a defined clinical activity endpoint at 8 weeks. The information available does not identify the statistical procedures used to analyze that endpoint. The explanations below are general statistical context, not a description of unreported methods used in this study.

What does a participant count describe?

For a binary outcome, each participant is classified according to whether a specified event occurred. A count reports the number classified as having the event; an accompanying denominator clarifies the group in which that count was observed. A proportion can also be used to express the count relative to the group size, but it should be paired with a clear definition of who was included and what counted as an event. The registry record gives the endpoint definition but does not report its observed count or denominator.

Here, the event definition permits clinical activity to be identified through changes in several measures. Absolute lymphocyte count may be assessed through peripheral blood complete blood count with differential or bone marrow examination, while the size of lymph nodes or the spleen may also be considered. The wording includes an “and/or” relationship, so the criteria allow more than one route to meeting the endpoint. The record does not report how these routes were combined in practice, whether all participants had all assessments, or how an incomplete assessment affected classification.

Why does uncertainty matter?

A point estimate gives a single summary of the observed data. It does not show how much uncertainty surrounds that summary. A confidence interval is a statistical range intended to convey uncertainty under an analysis method and its assumptions. A narrow interval generally indicates greater precision than a wide one, though the interpretation depends on the design and method. No confidence interval for the primary endpoint is reported in the registry record. Consequently, neither the estimated frequency of clinical activity nor its precision can be reviewed from the registry information.

A p-value, when used, evaluates how compatible data are with a stated statistical model or null hypothesis. It does not measure the size or clinical importance of an effect, and it does not establish causation. No primary-endpoint p-value or inferential analysis is reported in the registry record. A significance level of 0.05 appears in the planning assumptions for sample-size illustrations; that planning assumption should not be mistaken for a reported threshold used in the trial's own endpoint analysis.

What does a single-group design imply?

In a single-group study, the observed outcome is described among those receiving the study treatment. General statistical interpretation cannot make that observation equivalent to a randomized comparison. Without a control group, changes over time cannot be contrasted with outcomes under another condition within the trial. Natural variation, measurement differences, disease course, and other influences may contribute to observed changes. These are general considerations; the registry record does not state that any particular influence occurred in this study.

The record marks masking as none. In general, masking can reduce the influence of knowledge about treatment assignment on assessment or reporting, especially when outcomes involve judgment. A lack of masking does not establish that assessments were biased; it means that any assessment safeguards and procedures are relevant to interpretation. Such procedures are not reported in the registry record.

How should planning calculations be understood?

The registry's planning assumptions describe illustrations based on the observed effect, 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 the observed effect. These are planning assumptions, not evidence that this trial used a two-arm design: the registered study is single-group. The assumptions also do not constitute the trial's own sample-size justification, which is not reported in the registry record.

Sample-size calculations ask how much information a future design might require to detect a chosen effect under specified assumptions. Such calculations are planning illustrations, not observed power and not a way to recover missing outcome results. Their relevance depends on the assumptions, including the target effect and design. The registry record does not report the trial's own sample-size rationale. The calculated planning values are not described in the information available for this analysis and should not be inferred.

What is not known about the analysis?

The registry lists 5 outcome measures and 3 analyses, but the detailed analysis methods are not reported in the registry record. It does not specify whether the primary outcome was analyzed as a count, proportion, or another form, whether any model was fitted, or what assumptions were checked. It also does not state whether estimates were adjusted for participant characteristics or other factors. Those possibilities should not be attributed to the study without documentation.

General statistical practice calls for interpreting an estimate in light of its endpoint definition, analysis population, missing measurements, and uncertainty. These details are particularly relevant when endpoint classification can draw on several measurement sources. The registry record does not describe how missing or inconsistent observations were handled, how outcome assessments were timed beyond the stated 8 weeks timeframe, or whether any sensitivity analyses were performed. Thus, statistical concepts can clarify what the endpoint is intended to represent, but the registry information does not support reconstructing the study's analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 5 outcome measures and 3 analyses, along with several secondary outcomes: objective response, overall survival, progression-free survival, and incidence of adverse events. The primary endpoint concerns clinical activity at 8 weeks. The detailed relationship among the measures and analyses, including which analysis corresponds to which outcome, is not reported in the registry record.

When a study evaluates multiple outcomes or conducts multiple statistical tests, the chance of obtaining at least one apparently unusual result can increase. General approaches to address multiplicity include identifying a primary outcome in advance, setting an order for testing, or adjusting inference. The record identifies a primary endpoint, but it does not report a multiplicity strategy, whether testing was adjusted, or whether secondary analyses were intended to be confirmatory or descriptive. No such approach should be assumed.

The registry record does not report the analysis population for the primary or secondary outcomes, nor does it specify how participants with missing measurements were handled. It does not say whether all enrolled participants were included in the endpoint analysis, how discontinuation was treated, or whether missing data were imputed. The difference between the enrollment figure and the safety at-risk group is not explained in the record; it should not be interpreted as evidence of a particular exclusion or missing-data process.

These omissions matter because outcome counts depend on who was evaluated and how incomplete observations were classified. Without the analysis population, missing-data rules, and multiplicity plan, readers cannot fully assess the scope of the reported analyses. The registry record also does not report the primary endpoint result, limiting evaluation of any testing or adjustment in practice.

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: fatigue (15.4%), thrombocytopenia (15.4%), anemia (15.4%), facial swelling (7.7%), colitis (7.7%).

The posted safety figures identify the Treatment (Dasatinib) group, with 13 participants at risk for serious adverse events and 8 affected. The figures for other adverse events list 13 at risk and 0 affected. These are counts, not estimates of comparative risk: the study has no control group. The reason the safety at-risk count differs from the enrollment figure of 19 is not reported in the registry record.

The listed serious adverse-event terms are fatigue, thrombocytopenia, and anemia, each reported as 15.4%, and facial swelling, colitis, and hypocalcemia, each reported as 7.7%. These percentages should be read as registry-reported figures for the listed terms, not as evidence that the terms account for every serious event. The record does not provide further detail about event severity, timing, duration, recurrence, or how terms were attributed to treatment.

Serious adverse events and other adverse events are separate categories in the posted figures. A count of participants affected does not indicate the total number of event episodes, and the registry record does not provide that total. Nor does the absence of affected participants in the other-event count establish that no event of any kind occurred; it describes the specific category and figures recorded. These safety data provide descriptive information, but without a comparison group they do not establish how the event experience compares with another treatment or with no treatment.

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

This trial record provides a framework for asking whether patients with chronic lymphocytic leukemia who were studied for dasatinib sensitivity showed clinical activity during treatment. It describes a phase II, single-group design, an 8 weeks primary endpoint, and criteria based on lymphocyte count, bone marrow findings, lymph node size, or spleen size. The record also gives a treatment schedule and selected safety counts.

What it does not provide is the observed result for the primary endpoint. The number meeting the clinical activity definition, its uncertainty, and any inferential result are not reported in the registry record. As a result, readers cannot determine from this record how frequent the defined activity was or how precisely it was estimated. The study's completed status does not replace an outcome report.

Even if the primary result were available, the single-group design would constrain causal interpretation. A change observed during treatment would describe what happened in the treated group, but without a comparator it would not show how outcomes differed from those under another treatment or in the absence of treatment. This design limitation does not mean that a treatment effect was absent; it means the registry design does not directly estimate a between-group contrast.

The listed serious adverse-event figures describe affected participants in the safety group and a set of named terms. They do not establish comparative safety, and the registry record does not explain the difference between the enrollment figure and the safety at-risk group. The secondary outcomes are named, but their detailed results are not reported in the information available for this analysis.

Accordingly, the record supports a description of the question, design, endpoint definition, treatment, and recorded safety figures. It does not support a conclusion about the magnitude or precision of the primary clinical activity result, nor a comparative claim about treatment effects. Those questions require results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

The statistical value of this trial lies partly in how it makes an early clinical question explicit: it links an in vitro sensitivity concept with a defined clinical activity endpoint in patients with chronic lymphocytic leukemia. The endpoint combines laboratory and anatomical measurements, giving a concrete framework for deciding what constitutes activity at 8 weeks. Clear endpoint criteria are important because an event count is only interpretable when the event is defined.

The design also illustrates an important distinction between describing outcomes and estimating comparative effects. A single-group phase II study can characterize what was observed among treated participants, but it does not supply a concurrent control contrast. This distinction is essential when translating a descriptive clinical result into a causal claim. The registry identifies the design clearly, so its inferential limits can be recognized.

The posted adverse-event counts demonstrate why denominators and event definitions matter. Safety figures are reported for 13 participants at risk, while enrollment is recorded as 19; the record does not explain the difference. Naming that uncertainty is more informative than assuming the two groups of figures represent the same analysis population. Similarly, the serious-event terms and percentages are descriptive and should not be treated as comparative estimates.

The record also highlights the importance of complete outcome reporting. A registered endpoint and completed study status do not themselves reveal the observed result, its precision, or how missing measurements and multiple outcomes were handled. Those details are necessary for readers to assess what the study found and how robustly it was analyzed. In this case, the endpoint definition and design can be interpreted, while the primary result and important analysis details remain unreported in the registry record.

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 trial-specific limitation is the absence of a comparison group. The registered design is single-group, with no masking, so the record does not describe a randomized comparison that could separate treatment-associated change from other influences over time. This constrains causal interpretation even if clinical activity had been reported.

The primary endpoint combines several possible measurement routes: absolute lymphocyte count assessed through blood testing or bone marrow examination, and changes in lymph node or spleen size. The registry gives the thresholds but does not report how the routes were operationalized, how conflicting findings were handled, or whether every participant had the same assessments. The endpoint result itself is not reported in the registry record.

The safety figures use an at-risk group of 13, while enrollment is 19. The registry does not explain the difference or describe the safety analysis population. It also does not provide detail on event timing, duration, recurrence, or attribution. The listed adverse-event terms therefore offer limited context for interpreting the overall safety experience.

Further limitations arise from missing analysis information. The registry record does not report the statistical analysis plan, the sample-size justification, the analysis populations, missing-data procedures, or a multiplicity strategy. It lists 5 outcome measures and 3 analyses but does not give their detailed methods or results in the information available for this analysis. These gaps prevent evaluation of how the endpoint was analyzed and how secondary findings were handled.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Dasatinib in Treating Patients With Chronic Lymphocytic Leukemia — NCT01441882.
• Registry record last updated 2021-04-08; status last verified 2021-03.
• Results first posted 2018-02-15.
• 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.

18. Record Summary

The registry record describes NCT01441882, a completed phase II, single-group study sponsored by OHSU Knight Cancer Institute. It lists 19 enrolled participants, no masking, and dasatinib as the treatment. Dosing was described as once daily during course 1 and, if tolerated, twice daily in subsequent courses, repeated every 4 weeks in the absence of disease progression or unacceptable toxicity.

The primary endpoint was a participant count for clinical activity at 8 weeks, defined through specified decreases in lymphocyte count or bone marrow findings and/or lymph node or spleen size. The observed primary endpoint result and its statistical uncertainty are not reported in the registry record. Safety figures list 8 affected among 13 at risk for serious adverse events and 0 affected among 13 at risk for other adverse events. The record does not explain the safety denominator or provide the detailed analysis methods, missing-data approach, or multiplicity plan.