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 Study of Nilotinib in Ph+ CML-CP Patients With Low Imatinib Trough Plasma Concentrations (NCT01131325), a na phase 4 study. The primary outcome is Number of Treatment Failure Events up to 2 Years.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01131325 |
| Phase | Phase 4 |
| Condition | CML, Philadelphia Chromosome Positive (Ph+), Chronic Myelogenous Leukemia Chronic Phase(CML-CP) Patients With Low Imatinib Trough Levels |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Novartis Pharmaceuticals |
| Results posted | Yes |
2. Clinical Question
Population
People with Philadelphia chromosome-positive (Ph+) chronic myelogenous leukemia in chronic phase (CML-CP) and low imatinib trough concentrations. The primary-outcome description specifies concentrations <850 ng/mL. The registry record does not provide further eligibility details or a more specific description of the analyzed population.
Intervention
Nilotinib. The study record describes a single-group study, without a separate comparison treatment.
Comparator
There was no randomized control group or like-for-like comparator. Allocation is recorded as not applicable, and the study is identified as single group.
Primary question
How many ELN-guideline-defined treatment failure events occurred from study entry, up to 2 years, among the described participants treated with nilotinib? The registry record says the efficacy assessments were not collected and reported, and that 0 participants were considered for analysis.
The clinical question links a specific treatment context—low imatinib trough concentrations—with subsequent treatment failure events under nilotinib. The outcome was framed using European LeukemiaNet (ELN) guidelines, rather than as a direct comparison between nilotinib and another treatment. As a result, the study design could in principle describe events observed among participants receiving nilotinib, but it could not estimate a comparative treatment effect against a control group.
The registry lists secondary questions about ELN-defined optimal responses and suboptimal events; loss and duration of cytogenetic and molecular responses; event-free, progression-free, and overall survival up to 2 years; and adverse events. Those are planned outcome topics in the record, not evidence that the outcomes were measured or reported. The primary-outcome population description specifically states that efficacy and quality-of-life assessments were not collected and reported. The record therefore establishes the intended question and treatment setting, but does not provide outcome evidence with which to answer the efficacy question.
3. Trial Design
This was a Phase 4, multicenter, single-arm study of nilotinib. The registry records allocation as not applicable and masking as none. Thus, the described design has no randomized allocation and no blinded masking. The listed intervention is nilotinib, and the arm is named Nilotinib. No arm description beyond that name is recorded.
The study focused on Ph+ CML-CP participants with low imatinib trough levels. Its primary-outcome description specifies imatinib trough concentrations <850 ng/mL and treatment failure events defined by ELN guidelines. The registry identifies enrollment as 3 and status as terminated. It records a start date of 2010-10-21 and a primary completion date of 2011-05-12. The primary outcome timeframe is up to 2 years.
The record lists 7 secondary outcome measures, covering response categories, loss and duration of response, survival outcomes, and adverse events. It lists 0 analyses. The presence of outcome descriptions does not establish that the measurements were collected: the primary-outcome population description explicitly says efficacy and quality-of-life assessments were not collected and reported. The record does not report details of the planned visit schedule, treatment duration, dose, adherence monitoring, or procedures for assessing outcomes.
Because this was a single-group study, any observed outcomes would describe participants treated with nilotinib in this study context. Without a concurrent comparison group, they would not isolate a treatment effect from other explanations such as the participants’ underlying disease course, selection into the study, or changes in care. In this record, even a within-group outcome estimate is unavailable: the primary analysis population is stated as 0 because of premature termination and low enrollment. The registry does not report the reason for termination beyond that explanation.
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: A total of 3 participants were enrolled in the study, of which 1 discontinued the study due to Adverse Event (AE) and 2 participants discontinued as the study got terminated.
Overall Study
| Stage | Nilotinib |
|---|---|
| STARTED | 3 |
| COMPLETED | 0 |
| NOT COMPLETED | 3 |
Reasons for not completing this period:
| Reason | Nilotinib |
|---|---|
| Adverse Event | 1 |
| The participants discontinued the study as the study got terminated | 2 |
Analysis population for the primary outcome, as defined in the registry: The overall number of participants considered for analysis was "0" due to the premature termination of the study and low enrollment; The efficacy and quality of life assessments were not collected and reported in the 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.
Population: All enrolled participants.
| Characteristic | Unit | Nilotinib |
|---|---|---|
| Participants analysed | 3 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 3 |
| Race/Ethnicity, Customized: Caucasian | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Treatment Failure Events up to 2 Years, measured over up to 2 years.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the number of ELN-guideline-defined treatment failure events from study entry, with a stated timeframe of up to 2 years. It applies to the described CML-CP population with low imatinib trough concentrations treated with nilotinib. The concentration criterion in the endpoint description is <850 ng/mL.
A count of treatment failure events can provide a direct description of how often a prespecified clinical event was recorded during follow-up. Using a guideline-based definition can make the endpoint more consistent and clinically interpretable than an undefined judgment of failure. A time horizon also specifies the period over which events are intended to be counted. These are general features of event-count endpoints; the registry does not provide the full operational definition, event-adjudication procedures, or rules for handling multiple events in a participant.
The record states that the overall number of participants considered for analysis was 0 because the study ended prematurely and enrollment was low. It also states that efficacy assessments were not collected and reported. Consequently, the endpoint description identifies what the study sought to measure, but there is no reported treatment-failure count or estimate from which to assess the outcome. The registry does not report a denominator for an efficacy analysis, a distribution of follow-up, or a treatment-failure result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry describes an intended efficacy question but reports no efficacy result. Enrollment was 3, while the primary-outcome population description says 0 participants were considered for analysis due to premature termination and low enrollment. It further states that efficacy and quality-of-life assessments were not collected and reported. The number of treatment failure events is therefore not available in the registry record; it should not be read as zero events.
This distinction matters because absence of a reported outcome is not evidence that the outcome did not occur. A zero event count would be a measured result. In contrast, the record states that the efficacy assessment was not collected and that no participants entered the stated analysis population. Without collected endpoint data, neither an event count nor an event rate can be interpreted. The study's intended follow-up horizon of up to 2 years does not establish that participants were followed for that duration.
The single-group design would have limited causal interpretation even if outcome data had been available. It could have described outcomes among enrolled participants receiving nilotinib, but there is no randomized or other concurrent comparator in the record. A before-and-after or observed-event description in a single group cannot, on its own, determine what would have happened under another treatment or without the intervention. This is a general limitation of uncontrolled designs, separate from the fact that this record contains no efficacy findings.
The adverse-event fields do contain counts: the registry lists 0 serious adverse events among 3 at risk, 2 other adverse events among 3 at risk, and 0 deaths. These safety figures are distinct from the missing efficacy outcome. They should be interpreted as the registry's reported counts, not as a complete characterization of risks. The record does not list serious adverse-event terms, event timing, severity details for other events, or exposure duration. The small enrollment and missing efficacy follow-up also limit how broadly any safety observations can be generalized.
The registry lists 7 secondary outcome measures, but does not report their results, and lists 0 analyses. The planned outcome topics cannot substitute for observed results. No estimates, uncertainty intervals, hypothesis tests, or adjusted analyses are reported. Accordingly, the record supports a description of the study's question, design, termination, and listed safety counts, but it does not support a conclusion about the primary endpoint or the comparative effect of nilotinib.
9. Statistical Methods Explained
The registry describes a single-group study with no masking. In general, a single-group design records outcomes in participants receiving the intervention without a concurrent control group. Such a design can describe what was observed in the enrolled group, but does not provide the direct contrast needed to estimate how outcomes differed under an alternative treatment. Differences from an external expectation or historical experience may reflect differences in participant characteristics, follow-up, outcome measurement, or care as well as treatment. The registry does not report a planned external comparison.
What does the endpoint count represent?
The primary endpoint is a number of ELN-guideline-defined treatment failure events from study entry, over a timeframe of up to 2 years. Event counts are useful when the research question concerns occurrences of a defined clinical event. Interpretation depends on how events were defined, how they were detected, and what follow-up each participant contributed. For time-to-event outcomes, follow-up duration and censoring are also important: censoring means that an event was not observed before the participant's available follow-up ended, not that the event could never occur. The registry does not report the event-adjudication rules, participant-level follow-up, censoring approach, or a primary endpoint result.
The endpoint description references ELN guidelines, which gives a named framework for defining failure. General consistency in outcome definitions can reduce ambiguity and help readers understand what qualifies as an event. However, naming a guideline does not provide all operational details. The record does not specify how each criterion was applied, whether outcome assessment was blinded, or how ambiguous cases were resolved.
Why does the analysis population matter?
An analysis population identifies which participants contribute data to a particular result and how inclusion is determined. Different analysis populations can answer different questions. For example, an analysis of everyone assigned to a treatment in a randomized trial generally preserves the comparison created by randomization, while an analysis limited to participants with observed outcomes may be affected by why outcomes are missing. This is general statistical context; the present study is recorded as single group, not randomized.
Here, the registry's primary-outcome description says the overall number considered for analysis was 0 because of premature termination and low enrollment. It also says efficacy and quality-of-life assessments were not collected and reported. The registry does not explain whether any other analysis population was defined, how participants were handled in secondary analyses, or whether any collected data were excluded. The enrollment figure and analysis-population statement describe different aspects of the record and should not be treated as interchangeable.
What can uncertainty measures tell readers?
In general, a confidence interval expresses the range of values reasonably compatible with an estimate under a statistical model and its assumptions. A narrow interval indicates greater precision than a wide interval, although precision does not establish that an estimate is unbiased or clinically important. A p-value, when used, describes how unusual data would be under a specified null model; it does not measure the probability that a treatment works or that the null hypothesis is true. These concepts only apply when there is an estimate and an analysis to interpret. The registry lists 0 analyses and reports no primary efficacy estimate, confidence interval, or p-value.
For count outcomes, the statistical model should reflect how events arise and whether the data show more variability than a simple model assumes. General count models may use a Poisson distribution, which assumes that the event-count mean and variance are equal. Over-dispersion occurs when variability exceeds that assumption; ignoring it can make uncertainty appear too small. Other models can allow extra variability, but the appropriate choice depends on the data and analysis plan. The registry does not report a model, dispersion assumption, or analysis plan for the primary endpoint, so no model-specific result can be evaluated.
How should planning calculations be read?
Sample-size calculations are planning exercises: they ask how much information a future study might need under stated assumptions about an effect, variability, significance level, allocation, and statistical method. They are not observed outcomes, and they do not show that a study had a particular probability of detecting an effect after the fact. The registry record describes planning illustrations based on the observed effect, with equal allocation, a normal approximation, and a two-sided significance level of 0.05; time-to-event planning is described in terms of total events, while other planning outputs are expressed per arm. Those assumptions describe an illustration, not the design of this single-group study. The record does not provide a trial-specific sample-size justification or show that such planning assumptions governed enrollment.
Any planning illustration based on an observed effect depends on the quality and availability of that effect estimate. In this record, the primary efficacy outcome was not collected and reported and 0 participants were considered for its analysis. A planning value should therefore not be treated as observed power or as evidence about the treatment effect. More broadly, statistical interpretation requires results, an analysis population, and methods that match the design. Those elements are not reported for an efficacy analysis in this registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 7 secondary outcome measures in addition to the primary question. They address optimal and suboptimal ELN responses, loss and duration of cytogenetic and molecular responses, event-free, progression-free, and overall survival, and adverse events. When a study examines multiple outcomes, the chance of finding at least one apparently notable result can increase if each is tested without accounting for the number of comparisons. General approaches include prespecifying a primary outcome, controlling a family-wise error rate, or treating secondary analyses as exploratory. The registry record does not report a multiplicity adjustment, hierarchy of testing, or statistical analysis plan.
The record lists 0 analyses and says efficacy and quality-of-life assessments were not collected and reported. It therefore offers no reported tests or outcome estimates for which a multiplicity strategy can be assessed. The secondary outcome descriptions establish intended topics, but not that the outcomes were measured or analyzed.
The primary-outcome population statement gives 0 participants considered for analysis because of premature termination and low enrollment. The record does not describe whether data were missing after collection, why any individual assessments might have been missing, or whether missing-data methods such as imputation or sensitivity analyses were planned. Because efficacy assessments are stated not to have been collected and reported, this is not merely a question of how to handle a set of observed efficacy outcomes with some missing values. The registry does not report an efficacy dataset or an analysis population that could support such methods.
The registry also does not report interim analyses, stopping boundaries, or a sample-size justification. These details should not be inferred from the fact that the study was terminated. The record attributes the absence of an analysis population to premature termination and low enrollment, but does not give a more specific termination rationale.
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 |
|---|---|---|---|
| Nilotinib | 0 | 3 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Nilotinib | 0 of 3 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Nilotinib | 2 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Nilotinib |
|---|---|---|
| Muscle cramps - legs | Musculoskeletal and connective tissue disorders | 1 of 3 |
| Thrombocytopenia | Blood and lymphatic system disorders | 1 of 3 |
| Neutropenia | Blood and lymphatic system disorders | 1 of 3 |
| Nausea | Gastrointestinal disorders | 1 of 3 |
| Vomiting | Gastrointestinal disorders | 1 of 3 |
| Fatigue | General disorders | 1 of 3 |
| Rash | Skin and subcutaneous tissue disorders | 1 of 3 |
| Pruritus Genital | Skin and subcutaneous tissue disorders | 1 of 3 |
| Rhinitis allergic | Respiratory, thoracic and mediastinal disorders | 1 of 3 |
| Sore Throat | Infections and infestations | 1 of 3 |
The registry's safety fields list 0 serious adverse events among 3 at risk, 2 other adverse events among 3 at risk, and 0 deaths for the Nilotinib group. These are the posted counts; they do not supply event-level detail or a comparison with another group. The record lists no top serious adverse-event terms.
The serious adverse-event count should be read as a reported count, not proof that serious events could not occur. A small observed group and unspecified exposure and follow-up cannot establish the frequency of uncommon or delayed events. The record does not provide the definitions used for serious and other adverse events, their timing, severity or duration, or whether multiple events could occur for a participant. It also does not report exposure-adjusted rates.
The figure for other adverse events does not mean that the events were necessarily mild; severity details are not reported. Nor should the safety counts be combined with the missing efficacy outcome to draw a conclusion about treatment benefit or overall benefit-risk. They describe the limited safety information recorded for this study.
12. What the Result Does, and Does Not, Mean
The record establishes that a Phase 4, single-group study was intended to examine ELN-defined treatment failure events among Ph+ CML-CP participants with low imatinib trough concentrations receiving nilotinib. It also establishes that the study was terminated, enrollment was 3, and the primary-outcome description identifies 0 participants considered for analysis because of premature termination and low enrollment.
It does not establish how many treatment failure events occurred. The registry states that efficacy and quality-of-life assessments were not collected and reported. The missing endpoint result must not be interpreted as a finding of no treatment failures, and the planned outcome descriptions must not be mistaken for measured results. The stated follow-up timeframe of up to 2 years is the intended period for the endpoint, not evidence that participants completed that follow-up.
The record also does not show whether nilotinib changed outcomes relative to another treatment. There was no concurrent comparator, random allocation, or masked assessment recorded. Even if a single-arm outcome estimate had been available, it would describe outcomes in that group rather than establish a causal difference from an alternative. In this case, the absence of efficacy results prevents even that descriptive assessment.
The safety fields report 0 serious adverse events, 2 other adverse events, and 0 deaths, with 3 at risk for the serious and other adverse-event counts. These counts are limited observations, not a complete estimate of safety or a comparison against another treatment. The registry does not report the event details or follow-up needed for a broader assessment.
In short, the registry record is informative about the intended question, design, termination, and limited posted safety counts. It does not provide evidence to determine efficacy, compare treatments, or make a precise estimate of clinical outcomes.
13. Why This Trial Matters Statistically
This trial matters statistically because it illustrates the difference between a registered research question and an answer supported by outcome data. The record defines a primary endpoint, population, intervention, and intended timeframe, but reports that efficacy assessments were not collected and that 0 participants were considered for the primary analysis. Those details prevent an efficacy estimate, regardless of how clearly the endpoint was specified.
It also highlights the role of study design in determining what a result could mean. A single-group study can describe what happened among its participants, but it does not create a concurrent counterfactual for comparison. Randomization and a control group are common ways to make treatment comparisons more interpretable, though the appropriate design depends on the question. Here, allocation is recorded as not applicable, and no comparator is listed.
The record demonstrates why enrollment and analysis population are separate concepts. Enrollment is recorded as 3, while the primary analysis population is recorded as 0. Readers should not treat the enrollment count as though it were an efficacy denominator or presume that all enrolled participants contributed outcome data.
Finally, a registry can contain numerous planned outcomes and limited safety counts without containing efficacy findings. Listing secondary measures does not confirm that they were collected, and a safety count does not answer the primary efficacy question. Keeping these distinctions explicit helps prevent an unavailable result from being read as a null result, and prevents limited descriptive counts from being interpreted as comparative evidence.
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.
Several limitations specific to this record constrain interpretation. The study is marked terminated, with enrollment of 3 and 0 participants considered for the primary analysis. The record attributes this analysis-population status to premature termination and low enrollment, but does not report a more detailed reason for stopping. Efficacy and quality-of-life assessments were not collected and reported, leaving no primary endpoint estimate or secondary efficacy results to interpret.
The single-group design has no concurrent control, and allocation is not applicable. The study is also recorded as unmasked. The registry does not report procedures to reduce assessment bias, nor does it provide details of the planned treatment regimen, follow-up visits, adherence, or endpoint adjudication. These details should not be inferred from the intervention name or the general endpoint description.
The endpoint refers to ELN-defined treatment failure up to 2 years, but the record does not report how the criteria were operationalized, the amount of follow-up achieved, or how incomplete follow-up would be handled. There is no reported efficacy analysis population beyond the statement that it was 0. The record also lists 0 analyses and does not report a statistical analysis plan, missing-data approach, multiplicity strategy, interim analyses, or trial-specific sample-size justification.
Safety reporting is limited to aggregate counts. Serious adverse-event terms are not listed, and details such as event timing, severity of other events, exposure duration, and ascertainment methods are not reported. The small enrollment further restricts what these counts can say about uncommon events. Together, these limitations mean the registry record supports a narrow description of study conduct and posted counts, rather than a reliable estimate of efficacy or a comprehensive safety assessment.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of Nilotinib in Ph+ CML-CP Patients With Low Imatinib Trough Plasma Concentrations — NCT01131325.
- Registry record last updated 2021-05-20; status last verified 2020-10.
- Results first posted 2021-05-20.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01131325 is a Phase 4, multicenter, single-group study of nilotinib in Ph+ CML-CP participants with low imatinib trough concentrations. The primary question concerned the number of ELN-defined treatment failure events from study entry, up to 2 years, for participants with concentrations <850 ng/mL. The record lists enrollment of 3 and status as terminated.
The registry states that 0 participants were considered for the primary analysis because of premature termination and low enrollment, and that efficacy and quality-of-life assessments were not collected and reported. It lists 7 secondary outcome measures and 0 analyses. Safety fields list 0 serious adverse events, 2 other adverse events, and 0 deaths, with 3 at risk for the adverse-event counts. The record does not provide efficacy results or a comparative treatment estimate.