Lenalidomide (Revlimid) in Chronic Lymphocytic Leukemia (CLL): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lenalidomide (Revlimid) in Chronic Lymphocytic Leukemia (CLL) (NCT00267059), a non-randomized phase 2 study. The primary outcome is Number of Patients in Overall Response Categories.

2. Clinical Question

The clinical question is therefore descriptive: it concerns response categories and safety among patients treated in this study, rather than a treatment effect estimated against a control group. The registry lists chronic lymphocytic leukemia and leukemia as conditions. Its brief summary places the study in the context of patients who had already received standard therapy, but further details about prior treatments or eligibility criteria are not reported in the registry record.

The outcome description says that response was assessed after three 28-day cycles, at six months, and yearly thereafter using the NCI-Working Group Criteria. The listed categories are complete response, complete response with nodules, partial response, and no response. The primary question does not, by itself, indicate how many participants fell into any category. Because the registry record does not provide those counts or an analysis estimate, it is not possible to assess the observed frequency or precision of response from this record.

3. Trial Design

This was a Phase 2, non-randomized, single-group study with no masking. The intervention was lenalidomide. The registry records enrollment of 45 and identifies M.D. Anderson Cancer Center as the sponsor. The study began in 2005-12, reached primary completion in 2009-08, and is marked completed.

A single-group design follows participants receiving the intervention without a concurrent control arm. It can describe outcomes observed in the treated group, but it cannot separate the intervention's association with those outcomes from other influences, such as the course of the illness, prior care, participant selection, or changes over time. Without random allocation and a comparable control group, differences against an alternative treatment cannot be estimated from this design.

The primary outcome is a count of participants in overall response categories. The registry says the analysis was intention to treat and specifies that 44 patients received treatment. This is distinct from the enrollment figure of 45: the record does not explain the disposition of the remaining enrolled participant, so that detail is not reported in the registry record. The stated outcome assessment schedule begins after three 28-day cycles, with additional assessments at six months and yearly thereafter.

The registry record lists one outcome measure and no analyses. It does not report a detailed statistical analysis plan, a sample-size justification for the trial, allocation procedures beyond the non-randomized designation, or planned interim analyses. The separate planning assumptions associated with sample-size illustrations describe a hypothetical two-arm calculation, not the actual single-group design. Those assumptions should not be read as evidence that the study randomized participants or used a control group.

With no control arm, the central statistical task is to describe the response categories and safety events among the treated participants, while making clear the limits of such summaries. The registry record does not provide the primary outcome counts, confidence intervals, or other inferential estimates needed to judge the response estimate's precision.

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: Forty five patients were registered on this study. Forty four were evaluable. One patient never received treatment.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Analysis was intention to treat (ITT): Forty four patients received treatment.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients in Overall Response Categories, measured over Evaluated after three 28-day cycles of lenalidomide..

The primary endpoint is titled “Number of Patients in Overall Response Categories.” It is a count outcome: the number of participants classified in each response category. The registry defines overall response as complete response (CR) or partial response (PR). It also lists complete response with nodules and no response among the categories assessed under the NCI-Working Group Criteria.

The first stated assessment was after three 28-day cycles of lenalidomide. The outcome description also says that assessment occurred at six months and yearly thereafter. The registry does not provide numerical counts for the categories or identify a separate numerical estimate for each assessment time, so those results are not reported in the registry record.

A categorical response endpoint can make clinical outcomes easier to summarize than a collection of individual observations. It classifies each participant according to specified criteria, allowing readers to distinguish response levels rather than treating all participants as having the same outcome. The count is descriptive: it tells how many participants were assigned to each category in the analyzed group. It does not, on its own, establish how the outcome would compare with another treatment or what would have happened without lenalidomide.

The registry identifies the analysis population as intention to treat and states that 44 patients received treatment. It does not give the category counts or explain how missing assessments, if any, were handled. Without the observed counts and a clear account of assessment completeness, the endpoint definition can be understood, but the magnitude and precision of the observed response cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods help distinguish what a study observed from what can be inferred about a broader population or a treatment effect. In this study, the registry describes a single treated group and a categorical response outcome. The method description must therefore be interpreted in light of both the outcome definition and the absence of a comparator.

What does a single-group design estimate?

In general, a single-group study can summarize the outcomes observed among its participants. For a categorical endpoint, that may mean counting how many participants fall into each response category. Those counts describe the study group, but there is no concurrent randomized group against which to estimate a contrast. A comparison with an external benchmark would require a suitable benchmark and an explicitly defined analysis; neither is reported in the registry record.

The trial is listed as non-randomized, unmasked, and single group. These design features mean that random allocation cannot balance participant characteristics between treatment groups, because there is no second group. Unmasked conduct also means the registry does not describe masking of participants or study personnel. How outcome assessments were protected from potential influence is not reported in the registry record.

How should the response outcome be understood?

The primary outcome counts participants in overall response categories, with overall response defined as complete response or partial response. The stated criteria are the NCI-Working Group Criteria, and the listed categories include complete response, complete response with nodules, partial response, and no response. A categorical endpoint applies defined classification rules to participants; it does not automatically convey how much change each participant experienced or how outcomes compare with a control group.

The assessment description names three time references: after three 28-day cycles, at six months, and yearly thereafter. The registry record does not explain whether the primary count is tied to one specific time point or how results across assessments were combined. It also does not report a numerical outcome by time. Consequently, the assessment schedule is identifiable, but the precise analysis timing and observed response distribution are not reported in the registry record.

What does intention to treat mean in this record?

In general, an intention-to-treat analysis aims to analyze participants according to the group to which they were assigned, regardless of aspects of treatment received after assignment. In a single-group study without random allocation, that usual group-assignment contrast is not available. The registry nevertheless labels the analysis intention to treat and says that 44 patients received treatment. It does not describe the analysis handling of the enrolled participant who is not included in that treated count, or explain whether any other participants lacked outcome assessments. Those details are not reported in the registry record.

What can confidence intervals and tests add?

In general, a confidence interval describes the statistical uncertainty around an estimate under the assumptions of the method used. A narrow interval indicates greater precision than a wide interval, while neither interval alone resolves limitations such as selection bias or lack of a control group. A hypothesis test addresses compatibility between data and a specified statistical model or null hypothesis; its interpretation depends on the prespecified question and analysis. The registry record reports no confidence interval, test statistic, or p-value for the primary endpoint, and it does not state a statistical model for that endpoint.

Because the endpoint is categorical, analyses might in general report counts and proportions, with uncertainty quantified using a suitable method. No proportion or interval should be inferred from the registry's counts of participants receiving treatment or experiencing adverse events. Those are different quantities, and the primary response category counts are not reported in the registry record.

How should the sample-size illustrations be read?

The stated sample-size assumptions describe planning illustrations computed from an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. Such calculations are hypothetical planning exercises, not observed power and not proof that a study was adequately powered. The assumptions describe a two-arm setup that does not match this trial's single-group design. The registry record does not report the trial's own sample-size justification or the effect estimate used for those illustrations, and no numerical planning outputs are reported in the record.

General statistical interpretation also depends on transparency about exclusions, missing outcomes, repeated assessments, multiplicity, and analysis choices. These details affect how results should be understood and how much flexibility may exist in selecting analyses. The registry record provides the outcome definition and analysis population label, but does not report these additional methods. With no primary numerical results or detailed analysis plan, statistical precision and robustness cannot be evaluated.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, but the outcome description refers to assessments after three 28-day cycles, at six months, and yearly thereafter. It does not specify whether these are separate primary analyses, repeated descriptions of the same endpoint, or assessments used for a particular primary time point. The way multiple time points or response categories were handled in the analysis is not reported in the registry record.

Multiplicity concerns arise in general when several outcomes, time points, subgroups, or statistical tests are examined. The more analyses considered, the greater the opportunity for some results to appear notable by chance if no approach to multiplicity is specified. The registry record does not report a multiplicity adjustment or a plan for prioritizing analyses. It also lists no analyses, so no analysis-specific testing strategy is available to assess.

The record labels the analysis intention to treat and states that 44 patients received treatment, compared with enrollment of 45. It does not explain the status of the remaining enrolled participant. It also does not report the number of participants with evaluable response assessments at each stated time, the extent of missing outcome data, or any imputation or missing-data rule. These details are not reported in the registry record.

In general, missing outcome data can affect a categorical response summary if participants with unavailable assessments differ from those with observed assessments. The direction and size of any effect depend on the missingness pattern and the analysis method. Without information about outcome completeness and handling, the impact cannot be assessed. The absence of a reported analysis plan also limits assessment of whether the reported outcome and analysis choices were prespecified.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumonia (18.2%), fever of unknown origin (13.6%), pain (6.8%), anemia (4.5%), pneumocystis carinii pneumonia (4.5%).

The registry reports serious adverse events for the lenalidomide group among 44 participants at risk: 24 were affected. It separately reports other adverse events among 44 participants at risk: 34 were affected. These are counts of participants affected, not counts of all event episodes, and the registry record does not describe the event-counting rules in further detail.

The leading listed serious adverse event terms are pneumonia (18.2%), fever of unknown origin (13.6%), pain (6.8%), anemia (4.5%), Pneumocystis carinii pneumonia (4.5%), and hypotension (4.5%). The percentages should be read as registry-reported values. The record does not specify in this summary whether participants could contribute to more than one term, nor does it give additional detail about duration, severity grading, timing, or attribution for each event.

These safety figures describe events recorded in the treated group. Since there is no concurrent control group, they do not quantify an excess relative to another treatment or to no treatment. The figures also do not establish that lenalidomide caused each event. The registry record does not report a causal assessment for the listed events. Safety descriptions are useful for understanding what was recorded during the study, but they are not a controlled estimate of comparative risk.

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

The record establishes that a Phase 2, non-randomized, single-group study of lenalidomide was conducted in previously treated CLL. It defines the primary response categories and identifies safety as an additional study concern. The design and endpoint description make the study question understandable, but the record does not report numerical results for the primary response outcome.

As a result, the response counts, any proportion classified as complete or partial response, and the precision of those estimates are not reported in the registry record. There is no basis in this record for describing the magnitude of response or its uncertainty. The absence of these results should not be mistaken for an observed absence of response; it means the numerical response findings are unavailable in the registry record.

The safety information gives counts of affected participants and percentages for selected serious adverse event terms. These are descriptive observations in the treated group, not comparative estimates. They do not establish causation, and without a control group they cannot show how the event experience compares with an alternative.

The study's single-group design also limits conclusions about treatment effects. Even a fully reported response count would describe what happened among the enrolled participants, not establish what would have happened to similar patients under a different treatment or without lenalidomide. Other explanations and participant characteristics cannot be separated from treatment exposure using this design alone.

Thus, the record is useful for identifying the population context, intervention, response definition, assessment schedule, and reported safety counts. It does not provide the primary endpoint results or the detailed statistical methods needed to evaluate response precision, missing outcomes, or robustness. These limits concern what can be concluded from the registry record; they are not a judgment about the clinical value of lenalidomide.

13. Why This Trial Matters Statistically

This study illustrates why statistical interpretation begins with design, not just an endpoint label. The registry identifies a single-group study, so there is no randomized comparator and no direct treatment contrast. That distinction remains important even when a study has a clearly defined clinical outcome: a response category among treated participants is descriptive, while a treatment effect requires a meaningful comparison.

It also illustrates the difference between defining an outcome and reporting its results. The registry specifies overall response as complete response or partial response under stated criteria and gives assessment times. Yet the numerical category counts are not reported in the registry record. A reader can understand what investigators intended to measure without being able to determine the observed response distribution or its precision.

The enrollment and analysis-population descriptions raise another general statistical issue. The registry records enrollment of 45 and says 44 patients received treatment and were included in the intention-to-treat analysis, but does not explain the difference. Clear participant accounting is important because readers need to know who contributed to each outcome and what happened to participants without an observed endpoint.

Finally, sample-size planning language must be separated from the actual study design. The stated planning assumptions describe a hypothetical two-arm calculation, whereas the trial is recorded as single group. Planning illustrations do not demonstrate observed power, and they cannot supply missing primary outcome results. Together, these points show why design, analysis population, outcome availability, and uncertainty must be considered alongside any reported event counts.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation for statistical interpretation is that numerical results for the primary response categories are not reported in the registry record. Without those counts, it is not possible to assess the observed response distribution, calculate or review its precision, or compare results across the stated assessment times.

The study was non-randomized and single group, with no concurrent comparator. This prevents a controlled estimate of how outcomes differ under lenalidomide versus another treatment or no treatment. It also leaves the observed outcomes open to influences associated with participant selection, prior therapy, disease course, and other factors that are not separated by the design.

The registry records enrollment of 45 and states that 44 patients received treatment and were included in the intention-to-treat analysis. The status of the additional enrolled participant is not reported in the registry record. The number of participants with evaluable response data at each assessment, and any handling of missing assessments, are also not reported.

The response description includes more than one assessment time, but the record does not specify the primary time point for analysis or how repeated assessments were incorporated. A detailed statistical analysis plan, multiplicity procedures, interim analyses, and the trial's sample-size justification are not reported in the registry record. The planning assumptions described for hypothetical sample-size illustrations do not substitute for the trial's own design rationale.

Safety reporting is also descriptive. The registry gives participant counts and selected serious adverse event percentages, but further details about event timing, grading, attribution, and possible overlap among terms are not reported in the registry record. These limitations constrain interpretation of both efficacy and safety findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Lenalidomide (Revlimid) in Chronic Lymphocytic Leukemia (CLL) — NCT00267059.
• Registry record last updated 2012-08-07; status last verified 2012-08.
• Results first posted 2011-04-21.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed Phase 2, non-randomized, unmasked, single-group study of lenalidomide in previously treated chronic lymphocytic leukemia. M.D. Anderson Cancer Center is listed as the sponsor. Enrollment was 45; the primary analysis is described as intention to treat and includes 44 patients who received treatment.

The primary outcome was the number of participants in overall response categories, with overall response defined as complete or partial response under the NCI-Working Group Criteria. Assessments were described after three 28-day cycles, at six months, and yearly thereafter. Numerical primary response results and analysis estimates are not reported in the registry record.

Safety reporting includes serious adverse events affecting 24 of 44 participants and other adverse events affecting 34 of 44 participants. The record lists percentages for selected serious adverse event terms. Because the study has no concurrent control group, these data describe the treated group rather than comparative effects. Details about missing outcome data, the analysis plan, and the trial's sample-size justification are not reported in the registry record.