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 Dose Escalation Versus no Dose Escalation of Imatinib in Metastatic Gastrointestinal Stromal Tumors (GIST) Patients (NCT01031628), a randomized phase 3 study. The primary outcome is Evaluation of Lesions for Progression or Response Via RECIST Criteria.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01031628 |
| Phase | Phase 3 |
| Condition | Gastrointestinal Stromal Tumors |
| Allocation | Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 5 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sarcoma Alliance for Research through Collaboration |
| Results posted | Yes |
2. Clinical Question
Population
People with metastatic gastrointestinal stromal tumors (GIST) were the population of interest. The official title specifies patients with imatinib trough levels less than 1100 nanograms/mL for the dose-escalation comparison; the arm descriptions also include patients whose levels were at or above 1100 ng/mL and patients with exon 9 mutations. The registry record reports enrollment of 5, but it does not report a completed efficacy analysis population.
Intervention
For patients with blood levels less than 1100, one described strategy was dose adjustment of imatinib mesylate toward a goal blood level of at least 1100 ng/mL. The arm description for patients with exon 9 mutations allows continued imatinib at 400 mg or escalation up to 800 mg daily. These are descriptions of the planned strategies, not evidence that the strategies were compared successfully.
Comparator
For patients with blood levels less than 1100, the described comparator was continuing imatinib 400 mg daily without escalation. Patients with blood levels at or above 1100 were also described as continuing imatinib 400 mg daily. The record lists four arm descriptions, while its study model classification is single group; the record does not explain this difference.
Primary question
The stated purpose was to determine whether escalating imatinib to keep the drug blood level at or above 1100 ng/mL leads to better outcomes. The primary measure was evaluation of lesions for progression or response by RECIST criteria every 3 months. Because the study terminated early, the registry record says these data were not collected or analyzed. The central treatment question therefore remains unanswered by the posted efficacy results.
3. Trial Design
The registry describes a randomized Phase 3 study of dose escalation versus no dose escalation of imatinib in metastatic GIST patients. Masking is listed as none, so the record does not describe a masked comparison. The enrollment entry is 5. The study status is terminated, and the primary outcome population note states that data were not collected or analyzed due to early termination. These features sharply limit what can be learned from the posted record about comparative efficacy.
Four arm descriptions are listed. Arm A describes patients whose blood level was less than 1100 and who continued imatinib 400 mg daily. Arm B describes patients in that same blood-level category whose dose was adjusted toward a goal blood level of at least 1100 ng/mL. Arm C describes patients with levels at or above 1100 who continued imatinib 400 mg daily. Arm D describes patients with exon 9 mutations who continued imatinib mesylate at 400 mg or had a dose escalation up to 800 mg daily.
The record also classifies the study model as single group. That classification sits alongside the randomized designation and the four arm descriptions; the registry record does not explain how those entries fit together. It would be unsafe to infer a specific allocation process, a distinct analysis contrast, or how many participants were assigned to each described arm from those entries alone.
The primary outcome was scheduled for assessment every 3 months. The record gives no completed schedule of assessments, follow-up duration, or detailed operational plan beyond that timeframe. It also does not report why the study was terminated. The listed start and primary completion entries are 2010-01 and 2011-06, respectively, but the early termination note, rather than those dates, establishes that the stated primary outcome data were not collected or analyzed.
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
| Stage | 400 mg for Patients With Imatinib Blood Levels < 1100 | 600 or 800 mg for Patients With Imatinib Blood Levels < 1100 | 400 mg for Patients With Imatinib Blood Levels ≥ 1100 | 400, 600 or 800 mg for Patients With Exon 9 Mutation Tumors |
|---|---|---|---|---|
| STARTED | 0 | 1 | 3 | 0 |
| COMPLETED | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 1 | 3 | 0 |
Reasons for not completing this period:
| Reason | 400 mg for Patients With Imatinib Blood Levels < 1100 | 600 or 800 mg for Patients With Imatinib Blood Levels < 1100 | 400 mg for Patients With Imatinib Blood Levels ≥ 1100 | 400, 600 or 800 mg for Patients With Exon 9 Mutation Tumors |
|---|---|---|---|---|
| Study terminated early | 0 | 1 | 3 | 0 |
Analysis population for the primary outcome, as defined in the registry: Data were not collected or analyzed due to early termination.
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.
| Characteristic | Unit | Arm A | Arm B | Arm C | Arm D | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 0 | 1 | 3 | 0 | 4 | |
| Age Categorical: <=18 years | participants | — | 0 | 0 | — | 0 |
| Age Categorical: Between 18 and 65 years | participants | — | 0 | 3 | — | 3 |
| Age Categorical: >=65 years | participants | — | 1 | 0 | — | 1 |
| Age Continuous | years | — | 71 | 56.7 (SD 8.39) | — | 60.25 (SD 7.68) |
| Gender: Female | participants | — | 1 | 1 | — | 2 |
| Gender: Male | participants | — | 0 | 2 | — | 2 |
| Region of Enrollment: United States | participants | — | 1 | 3 | — | 4 |
6. Primary Endpoint
The registry lists the primary outcome as Evaluation of Lesions for Progression or Response Via RECIST Criteria, measured over Every 3 months.
| 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 measure was “Evaluation of Lesions for Progression or Response Via RECIST Criteria,” with assessment planned every 3 months. RECIST is a framework for evaluating changes in tumors on imaging and assigning response or progression categories. In general, structured criteria help make lesion assessments more consistent than relying on an informal impression of change. The registry record does not provide a more detailed endpoint definition, a specific response category, a measurement unit, or a statistical parameter for this outcome.
The endpoint was relevant to the stated question because the study aimed to evaluate whether dose escalation to reach a target imatinib blood level was associated with better outcomes. Assessment of lesions for response or progression could address tumor status over time, but the record does not report a completed assessment or any resulting comparison between strategies. It also does not state how response categories would have been combined for analysis or how changes over repeated assessments would have been handled.
Most importantly, the primary outcome population note says that data were not collected or analyzed due to early termination. Thus, the planned endpoint has no reported efficacy result in this registry record. A planned assessment schedule and a clinically relevant measure do not themselves establish whether lesions changed, or whether any change differed between treatment strategies.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main statistical fact is the absence of an analyzed primary outcome. The registry record identifies a lesion-based outcome assessed every 3 months, but explicitly says data were not collected or analyzed because the study terminated early. There is consequently no posted estimate of response, progression, or a difference between dose escalation and no dose escalation. No confidence interval or p-value for the primary question is reported. The record does not permit a conclusion about the direction or size of any treatment effect.
Enrollment was 5, and the registry lists four arm descriptions. That small enrollment, together with the absence of analyzed efficacy data, means the arm descriptions cannot be treated as evidence of comparative effectiveness. The record does not give the number enrolled in each arm, nor does it identify a completed analysis population for the primary endpoint. No arm-specific response or progression outcomes are reported.
Safety information is also limited. For Arm B, 1 participant was listed as at risk for other adverse events, and 1 was listed as affected; no serious adverse events were listed among the 1 at risk. For Arm C, 3 participants were listed as at risk for other adverse events and 2 as affected; no serious adverse events were listed among the 3 at risk. Arm A and Arm D each list 0 at risk for the serious and other adverse-event summaries, with 0 affected. These figures should be read as counts attached to the registry’s risk groups, not as estimates of comparative safety. Death counts are not reported in the record.
General statistical interpretation depends on both an effect estimate and its uncertainty. A confidence interval, when reported, describes a range of estimates compatible with the data under the analysis assumptions; a narrow interval indicates greater precision than a wide one. No such estimate or interval is available for this primary outcome. The absence of a reported analysis is not evidence that the treatment strategies had identical outcomes, and the record cannot distinguish no effect from an effect that was never measured or analyzed.
The design entries also require caution. The study is labeled randomized, but its model is labeled single group and its arm descriptions cover four groups or strategies. The record offers no reconciliation. Without an explained comparison and analyzed outcome data, the clinical question cannot be resolved from the registry entries. The results should therefore be described as unavailable, rather than positive, negative, or inconclusive on the basis of a treatment-effect estimate.
9. Statistical Methods Explained
There is little reported statistical analysis to interpret because the registry record says the primary outcome data were not collected or analyzed due to early termination. The record lists 0 analyses. It does not report an analysis method, an effect estimate, a measure of uncertainty, or a significance test for the primary question. The methods below explain general concepts relevant to interpreting a trial of this kind; they are not claims about analyses conducted in this study.
What would a treatment contrast represent?
In general, a treatment contrast compares outcomes under two strategies that are clearly defined for eligible participants. The stated question concerns dose escalation to maintain a blood level at or above 1100 ng/mL versus no dose escalation among patients with levels less than 1100. A meaningful comparison would need to specify which participants were eligible for each strategy, how assignment occurred, what outcome was compared, and the time point or follow-up rule used. The registry record gives arm descriptions but does not report an analyzed contrast or explain how the four listed arms align with the single-group model classification.
Randomization, in general, is intended to make treatment groups comparable at the start of a study by using an allocation process based on chance. That benefit is assessed through the design and analysis, not inferred from the word “randomized” alone. The record does not describe the allocation sequence, allocation concealment, or the number assigned to each arm. It lists masking as none, so it does not describe blinding of participants or study personnel.
What do effect estimates and confidence intervals tell readers?
In general, an effect estimate describes the observed difference or other contrast between treatment strategies. A confidence interval communicates uncertainty around that estimate under the model and assumptions used. Its width relates to precision: more uncertainty generally produces a wider interval, while greater precision generally produces a narrower one. A confidence interval is not a guarantee that the true effect lies in the interval. This trial’s registry record reports no primary-outcome effect estimate or confidence interval, so precision cannot be assessed.
A p-value, in general, measures how compatible the observed data are with a specified null hypothesis under a statistical model. It does not measure the size or clinical importance of an effect, and it does not establish that a treatment has or lacks an effect. No primary-outcome p-value is reported. With no analyzed primary outcome, a significance test cannot supply an answer to the stated question.
Why does the small enrollment matter?
In general, estimates from small studies can be highly sensitive to the outcome of each participant and may be imprecise. That concern is relevant given the registry enrollment of 5, but it is not possible to quantify precision because no efficacy results or uncertainty estimates are reported. Enrollment alone also does not reveal how many participants contributed to the primary endpoint, how many were assigned to each arm, or whether all enrolled participants had outcome assessments.
Sample-size calculations are planning tools that depend on assumptions about the treatment effect, variability or event rate, significance level, allocation, and analysis method. Any planning illustration based on an observed effect is not a trial’s observed power and is not evidence that the trial was adequately powered. The stated planning assumptions for illustrations include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect framed as a stated fraction of the observed effect. These are illustration assumptions, not a reported design justification for this study. The registry record does not report its own sample-size justification.
How should over-dispersion be understood?
General count-data methods sometimes account for over-dispersion, meaning that observed variability exceeds what a simpler statistical model assumes. Allowing for that extra variability can change uncertainty estimates and tests. The record does not identify a count-data model, report an over-dispersion assessment, or provide an analysis where that issue can be evaluated. It would therefore be inappropriate to attribute any particular model choice to this study.
What can be inferred from the safety counts?
Adverse-event counts describe reported events within listed risk groups. They are not automatically a randomized comparison, especially when group sizes are small or when the record does not explain who was included in each risk group. Serious and other adverse events are separate summaries, and a count of zero in one category does not mean that no adverse events of any kind occurred. The safety entries do not provide event descriptions, timing, exposure duration, or an explanation of missing values. Death counts are not reported.
Overall, the registry entries establish a planned randomized Phase 3 study and limited adverse-event counts, but do not establish an efficacy analysis. General statistical tools such as effect estimates, confidence intervals, and hypothesis tests require analyzed outcome data. Since these are absent, none can be used to quantify the primary treatment contrast.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises in general when a study makes several statistical comparisons or evaluates multiple outcomes, time points, subgroups, or analysis choices. If each is tested separately without an appropriate plan, the chance of at least one apparently unusual result can increase. A prespecified strategy can identify which outcome or comparison is primary and how additional tests will be interpreted. The registry record names a primary lesion evaluation and lists assessment every 3 months, but it does not report a multiplicity procedure, a hierarchy of outcomes, or how repeated assessments would have been analyzed. There are no reported analyses to which a correction or testing strategy can be applied.
The record does not report an analysis population such as all randomized participants, all treated participants, or participants with evaluable imaging. It says that primary outcome data were not collected or analyzed due to early termination. The number enrolled is 5, but the record does not state how many were randomized to each described arm, began treatment, completed follow-up, or had outcome assessments. Consequently, no intention-to-treat or per-protocol result can be identified.
Missing-data methods are also not reported. In general, missing outcome information can affect an estimate if participants with missing data differ from those with observed data, or if missingness relates to outcome or treatment. Methods may depend on why data are missing and the assumptions made. Here, the registry’s explanation is early termination and no collection or analysis of the primary outcome; it does not give participant-level reasons for missing assessments or any imputation, sensitivity analysis, or other handling plan.
The termination reason, any interim analyses, and the statistical analysis plan are not reported in the registry record. Their absence prevents evaluation of whether decisions about stopping, outcome selection, or analysis were prespecified. It does not establish that any unreported procedure did or did not occur.
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 |
|---|---|---|---|
| Arm B | 0 | 1 | 0.0% |
| Arm C | 0 | 3 | 0.0% |
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 |
|---|---|
| Arm A | 0 of 0 |
| Arm B | 1 of 1 |
| Arm C | 2 of 3 |
| Arm D | 0 of 0 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Arm A | Arm B | Arm C | Arm D |
|---|---|---|---|---|---|
| Insomnia | Psychiatric disorders | 0 of 0 | 1 of 1 | 1 of 3 | 0 of 0 |
| Nausea | Gastrointestinal disorders | 0 of 0 | 1 of 1 | 1 of 3 | 0 of 0 |
| Diarrhea | Gastrointestinal disorders | 0 of 0 | 0 of 1 | 2 of 3 | 0 of 0 |
| Fatigue | General disorders | 0 of 0 | 0 of 1 | 1 of 3 | 0 of 0 |
| Dysguesia | Nervous system disorders | 0 of 0 | 1 of 1 | 0 of 3 | 0 of 0 |
| Back Pain | Musculoskeletal and connective tissue disorders | 0 of 0 | 0 of 1 | 1 of 3 | 0 of 0 |
| Headache | Nervous system disorders | 0 of 0 | 1 of 1 | 0 of 3 | 0 of 0 |
| Pain | General disorders | 0 of 0 | 0 of 1 | 1 of 3 | 0 of 0 |
| Skin Infection | Infections and infestations | 0 of 0 | 1 of 1 | 0 of 3 | 0 of 0 |
The adverse-event entries distinguish serious events from other adverse events and give, for each arm, counts at risk and counts affected. Arm B lists 1 at risk for serious events and 0 affected; it also lists 1 at risk for other events and 1 affected. Arm C lists 3 at risk for serious events and 0 affected; it lists 3 at risk for other events and 2 affected. Arms A and D each list 0 at risk and 0 affected in both summaries.
These are small counts, and the registry does not provide event names in the serious-event list. It also does not report deaths. A zero serious-event count among a listed risk group is not proof that serious harm is impossible, and a count of other events does not by itself establish a difference between treatment strategies. The arm descriptions and listed risk groups should not be assumed to establish randomized, comparable safety denominators: the record does not explain their relationship to enrollment, treatment exposure, or follow-up.
General safety interpretation considers event type, severity, timing, exposure, and the number of people observed, alongside uncertainty and the design of the comparison. Those details are not fully available in this record. The posted counts are descriptive and do not support a broad comparative safety conclusion.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized Phase 3 study was registered to examine imatinib dose escalation strategies in metastatic GIST. Its stated objective concerned whether increasing the dose to maintain a blood level at or above 1100 ng/mL would lead to better outcomes for patients. The planned primary measure evaluated lesions for progression or response using RECIST criteria every 3 months. The record also describes continued imatinib 400 mg daily and dose-adjustment strategies, including an arm description for patients with exon 9 mutations.
What it does not establish is whether dose escalation improved, worsened, or had no effect on lesion response or progression. The registry states that primary outcome data were not collected or analyzed because of early termination. No treatment-effect estimate, confidence interval, or p-value for the primary question is reported. There is therefore no efficacy result to interpret as favoring either strategy.
The enrollment entry of 5 and the adverse-event counts provide limited descriptive context, but they do not fill the efficacy gap. The registry does not report arm-specific primary outcomes, an analysis population, or enough detail to interpret the safety entries as a comparison. The record also does not explain the relationship between its randomized designation, single-group model classification, and four arm descriptions.
In general, an unreported or unanalyzed outcome is different from a finding of no difference. A study that stops before collecting or analyzing its primary endpoint cannot demonstrate that strategies are equivalent, nor can it establish that one is superior. The appropriate reading is that the intended clinical question remains unanswered by the posted results. The termination reason and the study’s own sample-size justification are not reported in the registry record, so no further explanation for the absence of results can be established from these entries.
13. Why This Trial Matters Statistically
This study matters statistically because it illustrates the difference between a registered research question and an answer supported by analyzed data. The registry outlines a specific treatment question, a lesion-based primary measure, and a recurring assessment timeframe. Yet it also states that the primary outcome was not collected or analyzed after early termination. A clearly described objective is not itself a result: without outcome data and a treatment contrast, neither the direction nor precision of an effect can be assessed.
The record also shows why design labels and arm descriptions need to be interpreted together. It identifies the study as randomized and Phase 3, while classifying the model as single group and listing four arm descriptions. The registry does not explain this combination. Statistical interpretation depends on knowing which participants were eligible for each strategy and which groups were actually compared. Those details cannot be reconstructed from labels alone.
Finally, the study underscores the limits of small descriptive safety counts. Event counts can be reported even when the primary efficacy analysis is unavailable, but a few counts do not establish comparative risks. Denominators, event definitions, follow-up, and analysis methods all affect interpretation. Here, the record supplies only a narrow set of counts and does not report deaths.
The broader lesson is methodological rather than clinical: conclusions must match the evidence actually recorded. A planned endpoint, a stated treatment target, or a phase designation cannot substitute for observed outcomes and uncertainty estimates. The record supports describing the study’s aim, design entries, early termination, and limited safety information, but it does not support a claim about which dose strategy produced better outcomes.
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 most important trial-specific limitation is that the registry record says the primary outcome data were not collected or analyzed because the study terminated early. As a result, the central comparison has no reported efficacy estimate. The termination reason is not reported, and the record does not indicate how much treatment or follow-up occurred before the study stopped.
Enrollment was 5, but arm-specific enrollment is not reported. The record lists four arm descriptions while identifying the model as single group; it does not explain this discrepancy or provide enough detail to reconstruct the intended analysis groups. Although the study is labeled randomized, the allocation process and allocation counts are not reported. Masking is listed as none.
The primary outcome description names lesion evaluation for progression or response by RECIST criteria and gives an assessment interval of every 3 months. It does not report a more detailed definition, analysis time point, or approach to repeated assessments. No analysis population, missing-data procedure, or sensitivity analysis is reported. The record also does not report a statistical analysis plan, a sample-size justification, or interim analyses.
The adverse-event information is limited to counts at risk and affected, with no serious-event terms listed and death counts not reported. The record does not describe event timing, treatment exposure, or follow-up for these summaries. The small enrollment and absence of arm-specific efficacy results make it especially important not to treat the listed safety counts as a comparative estimate.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study of Dose Escalation Versus no Dose Escalation of Imatinib in Metastatic Gastrointestinal Stromal Tumors (GIST) Patients — NCT01031628.
- Registry record last updated 2013-09-09; status last verified 2013-08.
- Results first posted 2013-08-16.
- 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
The registry record identifies NCT01031628 as a randomized Phase 3 study of imatinib dose escalation versus no dose escalation in metastatic GIST patients. Masking is listed as none, the model as single group, and enrollment as 5. Four arm descriptions address blood levels below or at least 1100 ng/mL and patients with exon 9 mutations. The primary outcome was lesion evaluation for progression or response by RECIST criteria every 3 months.
The study status is terminated. The record states that primary outcome data were not collected or analyzed due to early termination and lists 0 analyses. Adverse-event entries report no serious events among the listed risk groups, while other-event counts are listed for Arms B and C. Death counts are not reported. The termination reason, primary efficacy results, and detailed statistical analysis plan are not reported in the registry record.