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 A Study to Evaluate Lenalidomide Combined With Dexamethasone in Relapsed or Refractory Diffuse Large B-Cell Lymphoma (NCT00474188), a non-randomized phase 2 study. The primary outcome is Tumor Response Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00474188 |
| Phase | Phase 2 |
| Condition | Diffuse Large B-cell Lymphoma |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 26 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Celgene Corporation |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned subjects with relapsed or refractory diffuse large B-cell lymphoma. The registry record lists diffuse large B-cell lymphoma as the condition and describes the intended population as having disease that had relapsed or was refractory. It does not give further eligibility details in the posted record.
Intervention
The intervention was lenalidomide, also identified as CC-5013, combined with dexamethasone. The study aimed to evaluate the safety and efficacy of this combination. The registry record does not report how the drugs were administered or the treatment schedule.
Comparator
There was no randomized comparator group. The study is recorded as non-randomized, single-group, and open-label, with no masking. Consequently, the record does not support a like-for-like comparison with a control treatment or a separate untreated group.
Primary question
The primary endpoint was tumor response rate at one year, defined in the registry record as the number of participants demonstrating complete or partial tumor response. The intended question was whether participants in this study demonstrated those responses. The study terminated prematurely, and the registry record says the efficacy analyses were not conducted, so it does not provide an answer from an analyzed primary endpoint.
This question is about the response observed in a particular treatment group, not about a comparative effect against another treatment. The registry record lists tumor control rate, duration of response, time to progression, and progression-free survival as secondary outcomes. It does not report analyses for those outcomes either. As a result, the registered objectives can be described, but the posted record does not establish the frequency of response or the course of disease outcomes.
3. Trial Design
This was a Phase II, multicenter, single-arm, open-label study of lenalidomide combined with dexamethasone in subjects with relapsed or refractory diffuse large B-cell lymphoma. The registry record classifies its allocation as non-randomized and its model as single group. It records no masking. Enrollment was 26. The study started in 2007-05, had a primary completion date of 2008-12, and is listed as terminated.
Because the study had a single group, it was designed to evaluate outcomes among participants receiving the combination rather than to estimate a randomized difference between treatment groups. Non-random allocation means treatment assignment was not randomized between comparator arms. In a single-group design, observed outcomes can describe what happened in the enrolled group, but they do not by themselves distinguish treatment effects from other explanations, such as the course of illness or factors affecting who entered the study. This is a general limitation of uncontrolled treatment studies.
The study was open-label, meaning masking was not used according to the registry record. The record does not provide further detail about how outcome assessments were conducted or whether any assessment safeguards were used. It identifies safety and efficacy as objectives, but the primary endpoint was tumor response rate. The record lists four secondary outcomes: tumor control rate, duration of response, time to progression, and progression-free survival.
The registry description says the study terminated prematurely and that efficacy analyses were not conducted. The reason for termination is not reported in the registry record. Nor does the record report a statistical analysis plan, any interim analyses, or the rationale used to select the enrollment target. The dates and design classifications describe the trial structure and status; they do not supply a clinical outcome estimate.
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 | Lenalidomide in Combination With Dexamethasone |
|---|---|
| STARTED | 26 |
| COMPLETED | 20 |
| NOT COMPLETED | 6 |
Reasons for not completing this period:
| Reason | Lenalidomide in Combination With Dexamethasone |
|---|---|
| Withdrawal by Subject | 1 |
| Study discontinued by sponsor | 5 |
Analysis population for the primary outcome, as defined in the registry: Study terminated prematurely. Analyses of efficacy not conducted.
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 | Lenalidomide in Combination With Dexamethasone |
|---|---|---|
| Participants analysed | 26 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 10 |
| Age, Categorical: >=65 years | Participants | 16 |
| Age Continuous | years | 66.7 (SD 11.42) |
| Sex: Female, Male: Female | Participants | 10 |
| Sex: Female, Male: Male | Participants | 16 |
| Region of Enrollment: Australia | participants | 4 |
| Region of Enrollment: Canada | participants | 2 |
| Region of Enrollment: United States | participants | 20 |
6. Primary Endpoint
The registry lists the primary outcome as Tumor Response Rate, measured over One Year.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | Participants |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was tumor response rate, with a timeframe of one year. The registry record describes the measure as the number of participants demonstrating complete or partial tumor response, referring to response criteria for non-Hodgkin lymphoma. The endpoint therefore focused on whether participants met either of those response categories during the stated timeframe. No observed count, rate, or confidence interval is reported in the registry record because the efficacy analysis was not conducted.
Response endpoints are used in clinical studies to describe whether a tumor has met predefined criteria for a response. Combining complete and partial responses can give a summary of participants meeting either category, while the underlying categories retain different clinical meanings. This is a general description of response endpoints; the posted record does not provide participant-level assessments or results by response category.
The registry identifies the unit as participants and the dispersion as a 95% confidence interval. A confidence interval is a statistical way to express uncertainty around an estimate; it reflects the precision of the estimate under the method used. In this study, the registry record does not report an estimate or interval to interpret. It also does not provide an analyzed denominator for the primary endpoint or details about how missing response assessments would have been handled.
The endpoint was intended to assess tumor response, not to establish a difference from a control group. Since the trial was single-arm and terminated before efficacy analyses were conducted, the registered endpoint remains a planned measure rather than a reported result. The record does not establish how many participants achieved complete or partial response.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive fact is that the registry record does not report a primary efficacy result. It says the study terminated prematurely and that the efficacy analyses were not conducted. Although the primary endpoint is named and its timeframe is given as one year, there is no reported number of participants with complete or partial response, no reported response-rate estimate, and no reported 95% confidence interval. Accordingly, the posted record cannot show the magnitude or precision of tumor response in the study group.
The enrollment entry is 26, but that figure should not be treated as the primary endpoint denominator. The record does not state how many participants were evaluated for response, whether all enrolled participants had follow-up through the one-year timeframe, or how participants without an assessment would have been counted. Without those details and an analysis, a response rate cannot be reconstructed from enrollment alone. No calculation of response or uncertainty is appropriate from the registry information.
The study was single-arm, non-randomized, and open-label. As a general statistical matter, a single-group outcome can describe participants enrolled in that group, but without a concurrent comparator it does not estimate a randomized contrast. Even if an analyzed response estimate were available, it would not by itself establish what would have happened to comparable participants under another treatment. Open-label status is also relevant context: knowledge of treatment assignment can affect some aspects of care or assessment, although the registry record does not describe whether or how that occurred in this study.
The registry lists tumor control rate, duration of response, time to progression, and progression-free survival as secondary outcomes. It does not report analyses of these outcomes. Their inclusion among planned outcomes should not be mistaken for evidence that results were observed or analyzed. No estimates, uncertainty intervals, or tests for these secondary measures appear in the record described.
The study status is terminated, with a primary completion date of 2008-12. The registry does not report why the study ended prematurely. It would be inappropriate to infer that the termination was caused by safety, lack of efficacy, recruitment, operational issues, or any other particular reason. The record also does not report an interim analysis or a reason for not conducting the efficacy analysis.
Any planning illustrations based on an observed effect require careful separation from trial results. Such calculations are not observed power and do not restore the missing endpoint analysis. The described illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. Those are planning assumptions, not a description of this single-arm study's design. The registry record does not provide a primary observed effect from which a trial-specific efficacy conclusion could be drawn.
In short, the registry documents the intended clinical question and design, but not an analyzed answer. The absence of reported efficacy analyses is not evidence that the combination had no effect, nor is it evidence that it produced a response. It means the posted record does not permit either conclusion.
9. Statistical Methods Explained
What does a confidence interval describe?
A confidence interval expresses the statistical uncertainty around an estimate under a specified method. Its width is related to precision: a narrower interval indicates less statistical uncertainty than a wider interval, while neither interval alone establishes that an effect is clinically important. The registry names a 95% confidence interval for the primary endpoint, but it reports no interval because it says the efficacy analysis was not conducted. There is therefore no interval whose width or compatibility with possible response rates can be assessed.
Why does the single-group design matter?
In a single-group study, the primary response outcome would describe the treatment group that was studied. A randomized comparison instead uses outcomes in assigned groups to estimate a difference between them, subject to the design and analysis assumptions. This trial is classified as single-group and non-randomized, so there is no randomized control contrast to interpret. This is a general distinction between descriptive outcomes in a cohort and comparative treatment-effect estimates. The registry record does not identify a control group or a comparator arm.
The absence of randomization does not make a descriptive result impossible, but it changes what can be inferred from it. Without a concurrent comparison group, an observed outcome cannot separate the contribution of treatment from other influences on the outcome. Open-label status is an additional design feature to consider. In general, unmasked knowledge of treatment can influence participant experience, clinical management, or outcome assessment. The record gives no details about assessment procedures, so the degree to which such concerns applied cannot be determined from the registry entry.
What does an endpoint count represent?
The primary endpoint is described as the number of participants demonstrating complete or partial tumor response, and its timeframe is one year. To interpret a response proportion in a completed analysis, a reader would ordinarily need both the response count and a defined analysis denominator. The registry record supplies neither an analyzed count nor an efficacy analysis. The enrollment entry is not a substitute for an endpoint denominator because enrollment does not establish which participants had evaluable outcome data or how an analysis population was defined. No response proportion can be derived from the record.
The endpoint description refers to response criteria for non-Hodgkin lymphoma. In general, prespecified criteria help make outcome classification more consistent by defining how response categories are assigned. The registry entry does not provide further operational details about assessments, timing within the one-year timeframe, independent review, or adjudication. Those details should not be assumed.
What can the design say about precision?
Precision depends on the amount and variability of information available for an estimate, as well as the analysis method. In a binary response setting, the observed outcome information and the denominator would be relevant to the uncertainty around the response proportion. Here, the efficacy analysis was not conducted and no interval is reported, so the precision of a response estimate cannot be evaluated. Enrollment alone does not reveal the precision of an unreported estimate.
The registry record describes planning illustrations using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. It also distinguishes total events for time-to-event illustrations from participants per arm for other illustrations. These assumptions describe hypothetical planning calculations, not this trial's single-group design. They should not be interpreted as the study's own sample-size justification or as evidence that its planned enrollment was adequate. The record does not report a sample-size justification or a statistical analysis plan.
Why is over-dispersion not the key issue in this record?
Over-dispersion is a general issue when data vary more than a chosen statistical model expects. For example, if a model assumes a particular level of variation but the observed data are more heterogeneous, standard errors and uncertainty assessments can be misleading unless the extra variation is addressed. This is a general concept, not a feature reported for this trial. The registry record does not identify an over-dispersion model, model fit assessment, or analyzed response data. With no efficacy analysis reported, there is no posted model result to evaluate for this issue.
What analyses are documented?
The record lists five outcome measures and zero analyses. The primary response measure and four secondary outcomes are identified, but listing outcomes is not the same as reporting their statistical analyses. The stated description explicitly says that the study terminated prematurely and the analysis was not conducted. No tests, effect estimates, confidence intervals, or analysis populations are reported for efficacy. The record does not report interim analyses or other statistical methods for those outcomes.
For these reasons, statistical interpretation is limited to the design and the status of the analysis. General descriptions of confidence intervals, endpoint denominators, and single-arm inference clarify what would normally be needed to interpret an analyzed result; they do not fill in values that the registry record does not contain.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists tumor response rate as the primary outcome and lists tumor control rate, duration of response, time to progression, and progression-free survival as secondary outcomes. Having several outcomes can raise multiplicity questions when multiple statistical tests are conducted, because the chance of a false-positive finding can increase across a family of tests. That general concern depends on which analyses were planned and how their interpretation was handled. The registry record does not report a multiplicity adjustment, a hierarchy among outcomes, or a statistical analysis plan.
The record says efficacy analyses were not conducted. It reports no outcome-specific estimates or tests, so there are no posted efficacy findings for which multiplicity adjustment can be assessed. The listed secondary outcomes should be understood as registered outcomes, not as analyzed results. The record also does not report whether any safety analyses were conducted or how safety outcomes were defined.
Missing-data handling is not reported in the registry record. There is no information about missing tumor assessments, loss to follow-up, outcome evaluability, or how participants without an assessment would have been classified. The enrollment entry of 26 does not establish the number contributing data to the primary endpoint. An analysis population, such as an intention-to-treat or evaluable population, is not reported in the registry record.
These omissions matter because both endpoint denominators and missing-outcome rules can affect interpretation of response estimates. They cannot be resolved by assuming that all enrolled participants were assessed or by selecting a particular missing-data method. The registry entry does not document an analysis sufficient to evaluate those choices.
11. What the Result Does, and Does Not, Mean
The registry record establishes that a Phase II study was undertaken to evaluate lenalidomide combined with dexamethasone in subjects with relapsed or refractory diffuse large B-cell lymphoma. It identifies tumor response rate at one year as the primary endpoint and describes response as complete or partial. It also documents a single-group, non-randomized, open-label design and enrollment of 26.
What the record does not establish is the primary efficacy result. It states that the study terminated prematurely and efficacy analyses were not conducted. It therefore does not report how many participants had a complete or partial response, the response rate, or the 95% confidence interval associated with an estimate. It also does not report results for the listed secondary outcomes. No treatment benefit, absence of benefit, or safety conclusion can be drawn from the unreported analyses.
Even if a response estimate had been reported, a single-arm study would describe outcomes in its enrolled group rather than provide a randomized comparison. General statistical interpretation would therefore distinguish a response observed in the study from a causal difference attributable to treatment. In this record, the absence of an analyzed response estimate makes even that descriptive conclusion unavailable.
The status of terminated and the description of premature termination are details about study conduct, not an explanation of why termination occurred. The reason is not reported in the registry record. It would be incorrect to interpret the termination itself as evidence for a particular efficacy or safety outcome.
Thus the record is informative about the planned question, intervention, endpoint, and design, but it does not provide an analyzed clinical result. The limits are not merely a matter of wide uncertainty around a reported estimate: no primary efficacy estimate or interval is reported at all.
12. Why This Trial Matters Statistically
This trial illustrates why a registry entry must be read as a record of both intended methods and available results. The study specifies a clinical population, a drug combination, a primary response endpoint, and secondary disease outcomes. Those details make the research question identifiable. At the same time, the registry states that the study terminated prematurely and that efficacy analyses were not conducted. A well-defined endpoint does not substitute for an observed and analyzed outcome.
The case also highlights the distinction between a single-arm study and a randomized comparison. A single-group design can be useful for describing outcomes in participants receiving an intervention, but it does not create a randomized control contrast. Statistical claims need to match that design. In this instance, the lack of an efficacy analysis means no response description is available in the record, and the design would in any event limit comparative causal interpretation.
It is also a useful example of why enrollment is not itself an outcome result. The registry records enrollment of 26, but does not report an endpoint denominator, response count, or confidence interval. Treating the enrollment entry as though it were a completed analysis would blur the difference between participation and evaluable outcome data.
Finally, the record distinguishes planned outcomes from completed analyses. Tumor control, duration of response, time to progression, and progression-free survival are listed, but their presence does not imply that findings were generated. For statistical readers, that distinction helps prevent a study objective or design feature from being mistaken for evidence about the treatment. The central statistical lesson is to state clearly what the record documents, what it does not report, and which inferences the design could support if results were available.
13. 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 consequential limitation for interpretation is the registry's explicit statement that the study terminated prematurely and efficacy analyses were not conducted. No primary response count, estimate, or 95% confidence interval is reported. As a result, the central efficacy question cannot be answered from the posted record.
The design also has limits for causal interpretation. It was single-arm and non-randomized, with no comparator group recorded. Outcomes from the treated group, even if reported, would not provide a randomized comparison against another treatment. The study was open-label and had no masking according to the registry record. The entry does not describe outcome-assessment procedures, so the implications of unmasked assessment cannot be assessed in detail.
The registry record does not report the reason for termination. It also does not state the number assessed for the primary endpoint, the analysis population, or how missing assessments were handled. Enrollment of 26 is reported, but enrollment alone does not establish the denominator for an efficacy analysis. No sample-size justification or statistical analysis plan is reported, and the record does not describe interim analyses.
Further limitations include the absence of reported estimates for the secondary outcomes and the lack of details about the operational conduct of response assessments. The registry identifies the one-year timeframe and response categories, but does not provide a completed analysis to assess precision or outcome completeness. These are limitations of the information in the registry record; they should not be taken to establish why the study ended or what its unreported results would have been.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: A Study to Evaluate Lenalidomide Combined With Dexamethasone in Relapsed or Refractory Diffuse Large B-Cell Lymphoma — NCT00474188.
- Registry record last updated 2009-09-02; status last verified 2009-08.
- Results first posted 2009-08-13.
- 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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17. Record Summary
This is the registry record for NCT00474188, a Phase II, multicenter, single-arm, open-label study of lenalidomide combined with dexamethasone in subjects with relapsed or refractory diffuse large B-cell lymphoma. The record lists enrollment of 26, a start date of 2007-05, primary completion in 2008-12, and status as terminated.
The primary endpoint was tumor response rate at one year, described as the number of participants with complete or partial tumor response and a 95% confidence interval. Secondary outcomes included tumor control rate, duration of response, time to progression, and progression-free survival. The registry says the study terminated prematurely and efficacy analyses were not conducted. It reports no primary response result or analyses for the listed secondary outcomes. The reason for termination, analysis population, missing-data approach, and statistical analysis plan are not reported in the registry record.