A Phase 2 Study of Lenalidomide in Patients With Relapsed or Recurrent Adult T-cell Leukemia-lymphoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Phase 2 Study of Lenalidomide in Patients With Relapsed or Recurrent Adult T-cell Leukemia-lymphoma (NCT01724177), a na phase 2 study. The primary outcome is Percentage of Participants Who Achieved a Complete Response, Unconfirmed Complete Response, or Partial Response as Assessed by the Efficacy-Safety Evaluation Committee (ESEC).

2. Clinical Question

3. Trial Design

This was a phase 2, multicenter, open-label, single-group study of lenalidomide in patients with relapsed or recurrent adult T-cell leukemia-lymphoma. The registry records enrollment of 26. Allocation is listed as not applicable and masking as none, consistent with a design that did not assign participants between masked treatment groups. The study status is completed.

The intervention was lenalidomide 25mg by mouth daily, continued until progressive disease or unacceptable toxicity. The registry describes the purpose as evaluating efficacy in patients who had previously received chemotherapy for adult T-cell leukemia-lymphoma. The recorded study start was 2012-11-12, and primary completion was 2014-11-20. The primary endpoint description notes a data cut-off date of 19 May 2017 and a maximum study duration of 134.1 weeks.

The primary outcome was the percentage of participants achieving complete response, unconfirmed complete response, or partial response, as evaluated by the Efficacy-Safety Evaluation Committee. The registry also lists secondary outcomes covering progression-free survival, time to progression, treatment-emergent adverse events, duration of response among responders, a broader response-or-stable-disease measure, and overall survival. These outcomes address different aspects of disease course and safety; their presence in the registry does not establish that numerical results for them are reported.

Because the study had one treatment group, it can describe responses and events recorded among treated participants, but it does not directly estimate a comparative treatment effect. The registry record does not report the protocol’s sample-size justification, detailed statistical plan, interim-analysis arrangements, or a specific rationale for the treatment duration rule.

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: This study included Japanese participants with relapsed or recurrent adult T-cell leukemia (ATL) who had previously received anti- ATL chemotherapy and who were categorized as having acute-lymphoma or unfavorable chronic-type ATL.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The Efficacy Evaluable (EE) population consisted of all participants who met basic protocol requirements (all eligibility criteria) and were evaluated after receiving at least one dose of lenalidomide

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: Intent to treat population consisted of all participants enrolled independent of whether they received study treatment or not.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants Who Achieved a Complete Response, Unconfirmed Complete Response, or Partial Response as Assessed by the Efficacy-Safety Evaluation Committee (ESEC), measured over From day 1 of study treatment to date of first documented CR, CRU or PR; Up to data cut-off date of 19 May 2017; maximum study duration was 134.1 weeks.

The primary endpoint is the percentage of participants in the Efficacy Evaluable population who achieved complete response, unconfirmed complete response, or partial response, as assessed by the Efficacy-Safety Evaluation Committee. The registry defines the overall response rate as the combination of those response categories. It describes complete response using findings across target and non-target lesions, organs, skin, peripheral blood, bone marrow, and the appearance of new lesions. Unconfirmed complete response and partial response use specified reductions in the sum of target-lesion product diameters, alongside criteria for other disease findings.

A percentage is useful for expressing how often a defined outcome occurred within a specified analysis population. The endpoint focuses on documented tumor response rather than time until progression or survival, which are listed separately as secondary outcomes. The observation period ran from day 1 of treatment to the first documented complete response, unconfirmed complete response, or partial response, with the registry describing follow-up to the data cut-off date of 19 May 2017.

The registry lists a 95% confidence interval for this percentage, but the response estimate and interval are not reported in the registry record. Without those values, the response frequency and its precision cannot be described from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a percentage endpoint, a 95% confidence interval, and an Efficacy Evaluable analysis population. It does not report the numerical response estimate, its interval limits, or the specific calculation method used for the interval. Those omissions limit the statistical conclusions that can be drawn from the record.

What does a percentage estimate describe?

In general, a percentage for a binary outcome expresses the share of an analysis population meeting a defined outcome. Here, the outcome is whether a participant achieved one of the specified response categories. The result depends on both the outcome definition and the population included in the analysis. This is why the endpoint definition and eligibility for the Efficacy Evaluable population matter alongside the percentage itself. The registry describes that population as participants who met basic protocol requirements and were evaluated after receiving at least one dose of lenalidomide. Its size is not reported in the registry record.

How should the confidence interval be understood?

In general, a confidence interval communicates the statistical uncertainty around an estimated quantity under the assumptions of the method used to calculate it. It is not a guarantee that the true value lies within the interval, nor does it capture every possible source of bias or uncertainty. For a percentage endpoint, an interval can help readers judge how precisely the response frequency has been estimated. The registry lists a 95% confidence interval for the primary endpoint, but neither the percentage nor the interval limits are reported in the registry record. The interval method is also not reported, so it should not be guessed.

What does the single-group structure mean?

In general, a single-group study estimates outcomes in the participants who receive the intervention, subject to the study’s eligibility rules, follow-up, and outcome measurement. It does not include a randomized internal comparator. Therefore, it cannot by itself separate the effect of treatment from other explanations for the observed course, such as the natural history of disease, participant selection, or other care. These are general interpretive limits, not claims that any particular alternative explanation occurred in this study.

Open-label status means masking was not used. In general, knowledge of treatment assignment can matter for outcomes that require judgment or participant reporting. The registry says the primary endpoint was assessed by the Efficacy-Safety Evaluation Committee, but it does not report details of committee procedures, blinding of assessors, or reproducibility checks. No assumptions about those arrangements should be made.

How do the secondary outcome types differ?

The registry lists Kaplan-Meier estimates for progression-free survival, time to progression, duration of response among responders, and overall survival. In general, Kaplan-Meier methods estimate the pattern of time to an event while accounting for participants whose event time is not observed during follow-up, under assumptions about censoring. The registry record does not report the numerical estimates, censoring details, or analysis conventions for these outcomes. The duration-of-response outcome is specifically described for responders, so its interpretation would also depend on how responders were defined and included.

The registry lists treatment-emergent adverse events and a percentage combining complete response, unconfirmed complete response, partial response, or stable disease as additional outcomes. These are not interchangeable with the primary endpoint: stable disease is not part of the primary response definition, and safety outcomes concern events rather than tumor response. The record does not report the detailed statistical procedures for these secondary outcomes.

What do planning illustrations tell readers?

In general, a sample-size calculation describes how many participants or events a hypothetical study might require under chosen assumptions. The planning illustration described for this analysis uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect set as a stated fraction of the observed effect. Those assumptions describe a hypothetical two-arm comparison, unlike this study’s single-group design. Such quantities are planning illustrations, not observed power, and they do not change the actual design or provide evidence that the study detected an effect.

The registry record lists 8 outcome measures and 1 analysis. Those entries do not substitute for a full statistical analysis plan. The plan for multiplicity, missing outcomes, prespecified subgroup analyses, and the exact methods used for estimates is not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Lenalidomide")
n      <- c(26)
events <- c(11)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Lenalidomide  26  11  42.3  23.4  63.1  25.5  61.1  25.5  61.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, including a primary response percentage and secondary response, time-to-event, and safety outcomes. It records 1 analysis. These registry entries do not establish how the study handled the chance of false-positive findings across multiple outcomes or analyses. A multiplicity procedure, such as a prespecified testing hierarchy or adjustment, is not reported in the registry record. The number of listed outcomes alone does not show whether formal hypothesis testing was planned or how results should be prioritized.

The primary endpoint is defined for an Efficacy Evaluable population comprising participants who met basic protocol requirements and were evaluated after receiving at least one dose of lenalidomide. The number of participants in that population and the handling of participants who did not meet those conditions are not reported in the registry record. Enrollment is recorded as 26, but that figure should not be treated as the primary endpoint denominator without a reported analysis-population count.

Missing-data procedures are not reported in the registry record. In general, missing outcome information can affect a percentage estimate if participants without an evaluable assessment are excluded or handled using an assumed outcome. The record does not describe imputation, sensitivity analyses, reasons for missing assessments, or the timing of response evaluations for participants without a documented response.

For the secondary time-to-event outcomes, the registry names Kaplan-Meier estimates, but censoring rules and methods for incomplete follow-up are not reported in the registry record. These omissions make it impossible to assess how missingness or follow-up termination may have affected those estimates.

12. Safety Results

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

Deaths

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: rash (7.7%), thrombocytopenia (7.7%), erythema multiforme (3.8%), toxic skin eruption (3.8%), anaemia (3.8%).

The registry lists 26 participants at risk for serious adverse events and 11 participants affected in the lenalidomide group. It separately lists 26 at risk for other adverse events and 26 affected, and records 22 deaths. These are separate safety summaries and should not be added together: participants may appear in more than one category, and the registry does not provide information that would establish whether the groups overlap.

The listed serious-event terms are rash and thrombocytopenia, each at 7.7%, and erythema multiforme, toxic skin eruption, anaemia, and non-cardiac chest pain, each at 3.8%. These are the registry’s reported percentages for the listed terms. They are not a complete description of event duration, severity distribution, timing, recurrence, or individual clinical circumstances, which are not reported in the registry record.

In general, an adverse event recorded during a study is not automatically evidence that the treatment caused it. The registry’s summary does not establish causality, and a single-group study has no internal untreated comparison for estimating excess event risk. The listed counts and terms should therefore be read as safety descriptions within the study, not as comparative risk estimates.

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

The study record establishes the context for interpreting a response outcome: a completed, open-label, single-group phase 2 study of lenalidomide in patients with relapsed or recurrent adult T-cell leukemia-lymphoma who had previously received chemotherapy. It specifies a primary response endpoint assessed by the Efficacy-Safety Evaluation Committee and defines the Efficacy Evaluable population. Those details clarify the question the trial set out to address.

The record does not report the numerical primary response percentage or its 95% confidence interval. Thus, it cannot support a statement about how frequent the primary response was, how precise its estimate was, or whether it met any benchmark. No response count or denominator should be inferred from the enrollment figure, because the primary analysis population size is not reported.

Even if a within-group response estimate is available elsewhere, a single-arm study does not directly show how outcomes would have differed with another treatment or without lenalidomide. In general, comparative treatment effects require a comparator and an analysis that accounts for the study design. The record provides no randomized comparison, and the statistical plan and external comparison basis are not reported.

The listed safety summaries identify affected participants, deaths, and selected serious adverse-event terms, but do not establish that lenalidomide caused any particular event. They also do not provide a controlled comparison of safety. The registry’s secondary outcomes cover disease progression, response duration, survival, and adverse events, but numerical results for those outcomes are not reported in the registry record.

Accordingly, the sound interpretation is bounded: the record describes the intended population, treatment, design, outcome definitions, and some safety counts, while leaving the primary efficacy estimate and several analysis details unavailable. It does not justify a conclusion about treatment benefit, lack of benefit, or comparative safety.

14. Why This Trial Matters Statistically

This trial illustrates why the endpoint definition and analysis population are essential parts of a clinical result. A response percentage only has a clear meaning when readers know which response categories count, who was eligible for the analysis, and how response was assessed. The registry specifies complete response, unconfirmed complete response, and partial response as the components of its primary endpoint, and defines the Efficacy Evaluable population in terms of eligibility and evaluation after treatment began.

It also demonstrates the distinction between describing an outcome and estimating a comparative effect. The study is single-group and open-label, so any response or safety summary pertains to participants treated in the study. There is no randomized internal comparator to support a direct contrast. This design feature affects the kind of statistical question that can be answered, regardless of whether an outcome is expressed as a percentage or as time to an event.

The record also shows why precision is part of interpretation. A percentage alone would not convey how uncertain its estimate is; the registry lists a 95% confidence interval, but the estimate and interval are not reported in the registry record. Without them, readers cannot evaluate the observed response frequency or its statistical precision. A stated endpoint is not a reported endpoint result.

Finally, planning calculations and observed trial evidence serve different purposes. The planning illustration uses assumptions for a hypothetical two-arm comparison, while the actual study has one treatment group. Recognizing that distinction prevents hypothetical sample-size quantities from being mistaken for evidence about the completed study’s power or findings. These are general lessons in reading trial records, grounded in the design and reporting details recorded for this study.

15. 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 interpreting efficacy is that the numerical primary endpoint result and its 95% confidence interval are not reported in the registry record. The size of the Efficacy Evaluable population is also not reported. Although the registry records enrollment of 26, enrollment cannot be substituted for the analysis denominator without confirmation that all enrolled participants were included in that population.

The single-group design provides no concurrent control for comparison. The study is also open-label, and details of endpoint assessment procedures beyond evaluation by the Efficacy-Safety Evaluation Committee are not reported in the registry record. This leaves uncertainty about assessor procedures and other potential sources of measurement or selection effects. These are limitations of what can be inferred from the record, not evidence that a particular bias occurred.

The registry lists several secondary outcomes, but their numerical results and detailed analysis methods are not reported in the registry record. The handling of missing outcome data, the approach to multiplicity, censoring conventions for time-to-event outcomes, and the statistical analysis plan are likewise not reported. The record therefore does not permit assessment of whether analyses followed prespecified methods or how incomplete follow-up was addressed.

The serious adverse-event summary reports affected participants and selected event terms, but it does not provide the full clinical context needed to assess timing, severity patterns, or causality. With no control group, the safety figures cannot be used to estimate comparative risks. These limitations constrain conclusions from the registry record; they do not by themselves determine what the full trial report may contain.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Phase 2 Study of Lenalidomide in Patients With Relapsed or Recurrent Adult T-cell Leukemia-lymphoma — NCT01724177.
• Registry record last updated 2018-05-29; status last verified 2018-03.
• Results first posted 2016-01-05.
• 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.

19. Record Summary

The registry describes a completed phase 2, multicenter, open-label, single-group study of lenalidomide for patients with relapsed or recurrent adult T-cell leukemia-lymphoma who had previously received chemotherapy. Enrollment is recorded as 26. The intervention was lenalidomide 25mg by mouth daily until progressive disease or unacceptable toxicity.

The primary endpoint was the percentage achieving complete response, unconfirmed complete response, or partial response, assessed by the Efficacy-Safety Evaluation Committee in the Efficacy Evaluable population. The registry defines this population and lists a 95% confidence interval, but the numerical endpoint estimate, interval, and analysis-population size are not reported in the registry record. Secondary outcomes include progression, response duration, survival, and adverse events. The record also lists safety counts and selected serious adverse-event terms, but the study has no concurrent comparator for causal or comparative interpretation.