This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Phase IV, Open-label, Multicenter Study of Dasatinib in Chronic-Phase Chronic Myeloid Leukemia (CP-CML) Patients With Chronic, Low-grade Non-Hematologic Toxicity to Imatinib (NCT01660906), a na phase 4 study. The primary outcome is The Number of Imatinib-related Adverse Events (AEs) That Were Resolved, Improved, Remained Unchanged, or Worsened After 3 Months of Dasatinib Treatment.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01660906 |
| Phase | Phase 4 |
| Condition | Chronic Phase Chronic Myeloid Leukemia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 39 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Bristol-Myers Squibb |
| Results posted | Yes |
2. Clinical Question
Population
Participants had chronic-phase chronic myeloid leukemia and chronic, Grade 1 or Grade 2 non-hematologic adverse events associated with imatinib. The primary outcome population is described as all treated participants. The registry record lists an enrollment of 39; the adverse-event safety group also lists 39 participants at risk.
Intervention
Participants switched from imatinib to dasatinib. The study is described as Phase IV and open-label, and the intervention arm is named Dasatinib (100 mg). The primary assessment concerns adverse-event status after 3 months of dasatinib treatment.
Comparator
The record describes a single-group study and does not list a concurrent comparator arm. The comparison is therefore based on the status of imatinib-related adverse events after the switch, rather than on a randomized comparison of dasatinib with another treatment.
Primary question
After 3 months of dasatinib treatment, how many imatinib-related adverse events were resolved, improved, unchanged, or worsened? The endpoint counts adverse events by their change in status. The registry record does not report the counts for these categories, so the magnitude and distribution of change cannot be described from this record.
This question is focused on chronic toxicity rather than on a comparison of leukemia treatments. The study aimed to characterize what happened to pre-existing, low-grade, non-hematologic adverse events following a treatment switch. Its open-label, single-group design means that the endpoint describes observed changes among participants treated with dasatinib; it does not by itself separate the effect of the switch from other influences on symptom reporting or adverse-event grading. The record also lists patient-reported symptom severity, interference, and quality-of-life measures as secondary outcomes, but their results are not reported in the registry record.
3. Trial Design
This was a Phase IV, open-label, multicenter, single-group study of dasatinib in people with chronic-phase chronic myeloid leukemia who had chronic, low-grade non-hematologic toxicity to imatinib. The registry record lists an enrollment of 39 and an intervention arm named Dasatinib (100 mg). Participants switched from imatinib to dasatinib; the primary outcome assesses imatinib-related adverse events after the switch. The record lists the study as completed, with a start date of 2012-12 and a primary completion date of 2015-10.
There is no concurrent comparator group in the recorded design. Allocation is listed as not applicable, and masking is listed as none. These characteristics matter for interpretation: the record describes an open-label experience in a single group, not a blinded or randomized comparison between treatments. Changes in recorded adverse-event status can be described, but the design does not establish how those changes would compare with outcomes under continued imatinib or another alternative.
The primary endpoint is a count of adverse events categorized as resolved, improved, unchanged, or worsened at 3 months after switching to dasatinib. The record defines improvement narrowly as a reduction from Grade 2 to Grade 1; resolution means the event is no longer present. Unchanged includes no improvement or worsening, and worsening means an increase in grade. The listed population is all treated participants.
Secondary outcomes include changes in patient-reported CML symptom severity and interference using the MDASI-CML, changes in quality of life using the EORTC QLQ, safety outcomes such as adverse events and discontinuations, and a percentage concerning improvement without worsening of imatinib-related chronic adverse events. The registry record does not report results for these outcomes or describe the detailed statistical plan, eligibility criteria, or procedures for assigning and reviewing adverse-event grades.
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: 39 participants enrolled and were treated.
Overall Study
| Stage | Dasatinib (100 mg) |
|---|---|
| STARTED | 39 |
| COMPLETED | 36 |
| NOT COMPLETED | 3 |
Reasons for not completing this period:
| Reason | Dasatinib (100 mg) |
|---|---|
| Discontinued due to study drug toxicity | 3 |
Analysis population for the primary outcome, as defined in the registry: All treated participants.
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: All treated participants.
| Characteristic | Unit | Dasatinib (100 mg) |
|---|---|---|
| Participants analysed | 39 | |
| Age, Continuous | years | 55.1 (SD 15.13) |
| Age, Customized: < 65 years | Participants | 27 |
| Age, Customized: >= 65 years | Participants | 12 |
| Gender: Female | Participants | 18 |
| Gender: Male | Participants | 21 |
| Race/Ethnicity, Customized: White | Participants | 12 |
| Race/Ethnicity, Customized: Black or African American | Participants | 1 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | Participants | 0 |
| Race/Ethnicity, Customized: Asian | Participants | 22 |
| Race/Ethnicity, Customized: Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race/Ethnicity, Customized: Other | Participants | 4 |
| Median Time Since CML-CP Diagnosis | months | 51.3 (3.9 to 214.6) |
| Median Duration of Imatinib Treatment | months | 51.2 (3.1 to 160.4) |
| Imatinib Dose at Baseline: < 400 milligrams | Participants | 19 |
| Imatinib Dose at Baseline: 400 milligrams | Participants | 20 |
| Best Baseline Response: MR4.5 | Participants | 10 |
| Best Baseline Response: MMR | Participants | 20 |
| Best Baseline Response: CCyR | Participants | 4 |
| Best Baseline Response: PCyR | Participants | 2 |
| Best Baseline Response: Cytogenetic Test Not Performed | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as The Number of Imatinib-related Adverse Events (AEs) That Were Resolved, Improved, Remained Unchanged, or Worsened After 3 Months of Dasatinib Treatment, measured over 3 months after switch to dasatinib.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | adverse event(s) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint counts imatinib-related adverse events according to their status after 3 months of dasatinib treatment. It distinguishes events that resolved, improved, remained unchanged, or worsened. The record defines resolution as the event no longer being present, and improvement as a reduction from Grade 2 to Grade 1. An event that did not improve or worsen is classified as unchanged, while an increase in grade is classified as worsening. The grading scale is described as ranging from Grade 1 to Grade 4, from mild through potentially life-threatening or disabling.
A count endpoint can describe the burden of events in each change category. It is used to address the study’s stated focus: what happened to chronic, low-grade, non-hematologic imatinib-related adverse events after a treatment switch. It differs from an endpoint that counts only participants, since a participant may have multiple adverse events. The registry record does not explain whether event-level observations were analyzed with methods accounting for multiple events within a participant, or how events with missing follow-up assessments were handled.
The endpoint is not a direct measure of leukemia control, and the primary result is not reported in the registry record. Without the category counts, readers cannot assess the observed distribution of event changes or their precision. Even if those counts were available, a before-and-after description in a single group would not alone establish that the treatment switch caused the changes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the primary outcome and its assessment time, but does not report the number of adverse events that resolved, improved, remained unchanged, or worsened. Consequently, the primary outcome cannot be quantitatively interpreted from this record. There is no reported primary estimate or confidence interval with which to assess either the observed pattern of change or its precision.
The safety information is more limited than a comparative analysis. The Dasatinib group lists 39 participants at risk, 11 affected by serious adverse events, and 36 affected by other adverse events. These figures describe the recorded safety experience; they do not show how outcomes compare with continued imatinib or another treatment. The serious adverse-event terms listed include pleural effusion, haemorrhoids, pneumonia, intervertebral disc protrusion, appendicitis, and anal fissure. The record also lists percentages beside these terms. It does not report a death count in the safety group information.
Because the trial is single-group and open-label, observed changes after switching are not a controlled estimate of the effect of dasatinib. Changes might reflect the treatment switch, the natural course of the events, changes in assessment or reporting, or other influences. This is a general limitation of interpreting before-and-after observations without a concurrent comparator; the registry record does not give enough detail to determine the contribution of any particular influence.
The registry record lists secondary outcomes for patient-reported symptom severity and interference, quality of life, adverse events, discontinuations, serious adverse events, deaths, and improvement in imatinib-related adverse events. It does not report their results. The record lists six outcome measures but no analyses. Without outcome estimates, uncertainty intervals, or an account of the analysis methods, readers cannot judge the precision of the findings, determine how missing observations may have affected results, or evaluate how the secondary outcomes relate to the primary question.
The enrollment figure is a description of the study, not evidence of statistical precision on its own. Precision depends on the outcome data and the analysis, including whether the unit is an adverse event or a participant and how repeated events within participants are handled. No such details are reported. Overall, the available record describes the question, design, and selected safety information, but does not provide the primary outcome result needed to characterize the observed change in imatinib-related adverse events.
9. Statistical Methods Explained
What does a single-group design establish?
A single-group study follows participants receiving the intervention without a concurrent control group. It can describe what was observed in that group over the specified assessment period. It cannot, by design alone, show what would have happened to the same participants under a different treatment. That missing counterfactual is why a change after switching is not automatically attributable to the switch.
In this study, the recorded primary outcome concerns adverse events previously associated with imatinib and assessed after participants switched to dasatinib. A before-and-after pattern could be relevant to the study question, but the registry record does not report the category counts. Even with counts, the design would remain vulnerable to influences such as natural fluctuation in symptoms, differences in how participants report symptoms over time, and changes in clinical assessment. These are general interpretive concerns, not claims about what occurred in this study.
What does open-label mean for measurement?
Open-label means treatment masking is not recorded. In general, knowledge of the treatment can influence expectations and reporting, especially for subjective symptoms or assessments involving judgment. This does not mean that any recorded assessment was biased. It means that readers should consider the possibility when interpreting reported changes, particularly when the outcome depends on grading or participant reports. The registry record does not describe blinding of outcome assessors or other procedures intended to reduce assessment bias.
Why distinguish events from participants?
The primary outcome unit is adverse events, whereas some safety outcomes are phrased in terms of participants. These are different units of analysis. A participant may experience more than one event, and the event count can therefore differ from the number of participants who experienced events. Treating every event as independent can also understate uncertainty if events from the same participant are related. General statistical methods for clustered or repeated observations can account for such dependence, but the registry record does not report whether any such method was used.
The definitions of resolved, improved, unchanged, and worsened make the categories clinically interpretable, but they also simplify change into discrete states. The record defines improvement as a change from Grade 2 to Grade 1, and resolution as absence of the event. The definition does not indicate how changes within a grade were handled, beyond classifying an event with no grade change as unchanged. It also does not report how a participant with several events was represented in analyses.
How should uncertainty be assessed?
A confidence interval is a statistical range that conveys uncertainty around an estimate under the assumptions of the analysis. A narrow interval generally indicates greater precision than a wide interval, while neither guarantees that the estimate is unbiased or that the analysis assumptions are appropriate. The registry record does not report confidence intervals for the primary endpoint. It therefore does not permit a direct assessment of the precision of the event-category results.
A p-value, when used, addresses compatibility between observed data and a specified statistical model under a null hypothesis. It does not measure the probability that a treatment works, and it does not describe the size or clinical importance of an effect. No analysis results or p-values are listed in the record. A statistical plan specifying which tests, models, or uncertainty measures were intended is also not reported in the registry record.
What do the planning assumptions mean?
The record describes a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It specifies that the target effect is a stated fraction of the observed effect; for time-to-event tables, the illustration concerns total events, and for other outcomes it concerns participants per arm. These are planning assumptions, not evidence that the trial used a two-arm design. The actual study is recorded as single-group, and the planning illustration is not the trial’s own design or an observed power calculation. Sample-size planning values, when presented, are hypothetical illustrations rather than observed trial outcomes.
In general, a planning calculation estimates the sample size needed to detect a chosen effect under stated assumptions. Its result depends on those assumptions and is not a measure of the probability that a completed study has demonstrated an effect. The registry record does not report a sample-size justification for the actual single-group study or a statistical plan linking the planning illustration to its primary event-count endpoint.
What can be concluded from the listed analyses?
The record lists no analyses. This means that no statistical test, model, or analysis population is specified in the recorded results. It should not be taken as evidence that no analysis occurred outside the registry; rather, the analytical details are not reported in the registry record. Without them, readers cannot determine how the event counts were summarized, whether uncertainty was quantified, or whether results were adjusted for any factors. The primary outcome result itself is also not reported, limiting interpretation before any question of method can be resolved.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists a primary outcome and several secondary outcomes, including patient-reported symptom severity and interference, quality of life, safety events, discontinuations, and improvement in imatinib-related adverse events. When a study assesses multiple outcomes, the chance of finding an apparently notable result by chance can increase if many statistical tests are performed. General approaches include prespecifying a primary comparison, adjusting for multiple testing, or treating secondary analyses as exploratory. The registry record does not report a multiplicity strategy, the planned tests, or an analysis hierarchy beyond identifying the primary outcome.
The record lists six outcome measures and no analyses. It does not report outcome estimates for the primary or secondary measures, so readers cannot assess whether selective reporting or multiplicity adjustments affected interpretation. This is a limitation of the available record, not evidence that analyses were omitted in practice.
Missing-data handling is not reported in the registry record. The primary outcome population is described as all treated participants, but the record does not explain whether every participant contributed an assessment at the 3-month time point, how incomplete assessments were treated, or whether any imputation or sensitivity analysis was used. These choices can matter: excluding participants without follow-up may produce a different summary from methods that make assumptions about their unobserved outcomes.
The distinction between participants and adverse events also matters for missingness. The record does not say whether missing information was assessed at the participant level, the event level, or both. The analysis population for secondary outcomes is not reported in the registry record. Without outcome-specific denominators and missing-data methods, completeness and possible bias cannot be evaluated.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Dasatinib | 11 | 39 | 28.2% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Dasatinib | 36 of 39 |
Most frequent serious adverse event terms
| Event term | Organ system | Dasatinib |
|---|---|---|
| Pleural effusion | Respiratory, thoracic and mediastinal disorders | 2 of 39 |
| Haemorrhoids | Gastrointestinal disorders | 2 of 39 |
| Pneumonia | Infections and infestations | 2 of 39 |
| Intervertebral disc protrusion | Musculoskeletal and connective tissue disorders | 2 of 39 |
| Appendicitis | Infections and infestations | 1 of 39 |
| Anal fissure | Gastrointestinal disorders | 1 of 39 |
| Rib fracture | Injury, poisoning and procedural complications | 1 of 39 |
| Pulmonary oedema | Respiratory, thoracic and mediastinal disorders | 1 of 39 |
| Pneumothorax | Respiratory, thoracic and mediastinal disorders | 1 of 39 |
| Pulmonary arterial hypertension | Respiratory, thoracic and mediastinal disorders | 1 of 39 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Dasatinib |
|---|---|---|
| Headache | Nervous system disorders | 15 of 39 |
| Diarrhoea | Gastrointestinal disorders | 11 of 39 |
| Pleural effusion | Respiratory, thoracic and mediastinal disorders | 10 of 39 |
| Dyspnoea | Respiratory, thoracic and mediastinal disorders | 10 of 39 |
| Fatigue | General disorders | 10 of 39 |
| Rash | Skin and subcutaneous tissue disorders | 10 of 39 |
| Nausea | Gastrointestinal disorders | 8 of 39 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 6 of 39 |
| Cough | Respiratory, thoracic and mediastinal disorders | 6 of 39 |
| Pyrexia | General disorders | 6 of 39 |
Serious events with the highest arm-level rate: pleural effusion (5.1%), haemorrhoids (5.1%), pneumonia (5.1%), intervertebral disc protrusion (5.1%), appendicitis (2.6%).
The Dasatinib safety group lists 39 participants at risk, 11 affected by serious adverse events, and 36 affected by other adverse events. These are separate safety summaries as recorded; the registry record does not state whether participants affected by serious events are also included in the other adverse-event count. The figures should not be added together or interpreted as mutually exclusive participant groups.
The serious adverse-event terms listed are pleural effusion, haemorrhoids, pneumonia, intervertebral disc protrusion, appendicitis, and anal fissure. Each term is accompanied by a percentage in the record: 5.1% for pleural effusion, haemorrhoids, pneumonia, and intervertebral disc protrusion, and 2.6% for appendicitis and anal fissure. The record does not explain in this summary whether each term represents participants, events, or a particular reporting convention, so the percentages should be read as registry-listed values rather than recalculated rates.
Serious adverse events are not synonymous with all adverse events, and the listed terms do not establish causation. The record does not report a death count in the safety group information. Since there is no control group, these safety data describe the recorded experience during dasatinib treatment but do not permit a like-for-like comparative safety estimate.
12. What the Result Does, and Does Not, Mean
The study asks a focused descriptive question: how imatinib-related chronic, low-grade, non-hematologic adverse events were classified after participants switched to dasatinib. The endpoint categories—resolved, improved, unchanged, or worsened—make clear what kind of change the investigators intended to count. However, the registry record does not report the primary category counts, so it does not establish the observed pattern of change or how precisely it was estimated.
The study design also sets limits on what the results could mean. It is an open-label, single-group study, with no concurrent comparator. An observed change after switching would be a description of outcomes in this group, not a randomized estimate of the difference between dasatinib and continued imatinib. General factors such as symptom fluctuation, expectations, and assessment practices can affect before-and-after observations; the record does not quantify their role.
The safety information documents affected participants and lists serious adverse-event terms, but it is not a comparative safety analysis. The registry record does not report a death count in the safety group information, and it does not provide outcome results for the listed patient-reported or quality-of-life measures. Those outcomes should not be treated as evidence of benefit or harm in the absence of their results and analytical context.
Accordingly, the record supports a description of the trial’s aim, design, endpoint definitions, and selected safety listings. It does not support a quantitative conclusion about the primary outcome, the degree of uncertainty around any change, or a causal claim about the treatment switch. The absence of reported results is a limit on interpretation, not a finding that no change occurred.
13. Why This Trial Matters Statistically
This trial is statistically notable for the distinction between an event-count question and a participant-count question. Its primary endpoint counts adverse events by change category, while the safety summaries report affected participants. Those measures answer different questions and require clear denominators and analysis units for interpretation. The registry record does not report the primary counts or enough analysis detail to determine how multiple events within the same participant were handled.
The design also illustrates why a clearly defined outcome does not by itself provide a causal comparison. The record specifies a 3-month assessment and categories for event status, but the study is single-group and open-label. The resulting question is descriptive: what happened to the recorded events after the switch? A control group and a prespecified comparative analysis would address a different inferential question; neither is part of the recorded design.
Finally, the record separates the stated study purpose from the results available for statistical interpretation. It identifies secondary patient-reported and safety outcomes, but does not report their results or analyses. The planning illustration uses assumptions that differ from the actual single-group design, so it should be understood as a planning exercise rather than evidence about the trial’s achieved precision. Together, these features show why outcome definitions, study design, analysis methods, and complete results all matter when reading a clinical trial 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 primary outcome result is not reported in the registry record. This is the central limitation for interpreting the study’s stated question: the record gives category definitions and the assessment time but not the number of events in each category, nor an estimate of uncertainty.
The single-group, open-label design does not provide a concurrent treatment comparison. Any changes in adverse-event status would be descriptive and could not, on their own, establish that the switch caused those changes. The registry record also does not describe assessor blinding, the process for grading events, or whether the same procedures were used throughout follow-up.
The endpoint counts adverse events, while the safety summaries refer to affected participants. The record does not report how related events within a participant were handled analytically, whether events were assessed as independent observations, or how multiple events per participant affected uncertainty. It also does not provide the primary outcome counts or outcome-specific analysis populations.
Missing-data procedures, the statistical analysis plan, multiplicity handling, and any sensitivity analyses are not reported in the registry record. The secondary outcome results are also not reported. The safety listing includes affected-participant counts and serious-event terms, but the record does not provide a comparator or a death count in the safety group information. These gaps limit assessment of completeness, precision, and comparative interpretation; they do not establish that analyses or assessments were absent from the conduct of the study.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Phase IV, Open-label, Multicenter Study of Dasatinib in Chronic-Phase Chronic Myeloid Leukemia (CP-CML) Patients With Chronic, Low-grade Non-Hematologic Toxicity to Imatinib — NCT01660906.
- Registry record last updated 2016-11-22; status last verified 2016-11.
- Results first posted 2016-11-22.
- 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.
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18. Record Summary
NCT01660906 is a completed Phase IV, open-label, multicenter, single-group study of dasatinib in chronic-phase chronic myeloid leukemia among participants with chronic, low-grade non-hematologic toxicity to imatinib. The intervention arm is named Dasatinib (100 mg), and the registry record lists an enrollment of 39.
The primary endpoint counts imatinib-related adverse events that resolved, improved, remained unchanged, or worsened after 3 months of dasatinib treatment. The record defines these categories but does not report their counts. Secondary outcomes include patient-reported symptoms, quality of life, and safety measures; their results are not reported in the registry record.
The safety group lists 11 participants affected by serious adverse events and 36 affected by other adverse events, with 39 at risk. The record lists serious-event terms and percentages but does not provide a concurrent comparator. No analyses are listed, and the detailed statistical plan and missing-data procedures are not reported in the registry record.