Lenalidomide and Rituximab in Subjects With Previously Untreated Indolent Non-Hodgkin's Lymphoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lenalidomide and Rituximab in Subjects With Previously Untreated Indolent Non-Hodgkin's Lymphoma (NCT01316523), a na phase 2 study. The primary outcome is Response Rate to Treatment.

2. Clinical Question

In practical terms, the study asked whether participants receiving the two-drug regimen had a best recorded response meeting the protocol definition of complete or partial response. That definition groups two response categories together; it is not a measure of how long a response lasted, whether participants remained alive, or how much treatment participants received. The registry lists time to next treatment, overall survival, treatment-related adverse events, and duration of response from start of therapy among secondary outcomes, but does not report their results.

The study is not a randomized comparison. Any response observed in the group could not be separated statistically from factors such as the participants' disease characteristics, their eligibility for enrollment, or the natural course of disease using a concurrent control group. The record describes the question the study intended to address, but it does not supply a primary response result from which to describe the observed frequency or precision of response.

3. Trial Design

This was a Phase II, single-group study sponsored by the University of California, Davis. The registry records enrollment of 30 and status as TERMINATED. Its recorded start is 2010-12 and its primary completion date is 2023-09-12. These dates describe the registry record; the reason for termination and any consequences for data collection or analysis are not reported in the registry record.

Participants were to receive lenalidomide and rituximab together. The summary describes lenalidomide 20 mg daily on days 1–21 of a 28 day cycle, continuing until disease progression, unacceptable side effects, or after twelve cycles if the participant was responding well. Rituximab was described as 375 mg/m2 weekly for 4 weeks, starting on day 15 of cycle 1. The summary states that a second course would be given after 4 cycles to participants responding well; the arm description gives additional conditions and dosing days, but its final wording is incomplete. No assumption should be made about details that the registry text does not complete.

The study was unmasked: masking is listed as NONE. Allocation is listed as NA because there was no treatment assignment between parallel arms. With a single group, the study can describe outcomes among treated participants, but it cannot provide a randomized estimate of how outcomes differ from those under an alternative treatment or no treatment. A comparison with an external population would require information and assumptions not reported in the registry record.

Blood samples were to be collected to assess immune system functioning. The primary outcome was response rate, with assessment at 4 months. The record defines response as the proportion whose best response was complete response, confirmed or unconfirmed, or partial response under the stated criteria. Secondary outcomes include time to next treatment, overall survival, treatment-related adverse events, and duration of response from start of therapy. Although the record lists 5 outcome measures, it reports no analysis for the primary endpoint and no analysis count. The protocol's sample-size justification, detailed statistical plan, analysis populations, and reason for termination are not reported in the registry record.

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

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 Response Rate to Treatment, measured over 4 months.

The primary endpoint is the proportion of participants whose best response was complete response or partial response. A complete response is described as disappearance of all detectable clinical evidence of disease and disease-related symptoms that were present before therapy. A partial response is regression of measurable disease without new sites of disease. Stable disease and progressive disease do not meet the primary response definition. Complete response may be confirmed or unconfirmed.

The assessment was specified for 4 months and was to use the Revised Working Group Response Criteria for Malignant Lymphoma. A proportion gives a clinically interpretable summary of how many participants in the study group met the response definition. It does not, by itself, convey the depth or duration of response, later disease progression, survival, or adverse events. Those are distinct outcomes, several of which are listed as secondary outcomes.

For statistical interpretation, the numerator is the number of participants meeting the response definition and the denominator is the population assessed for that endpoint. The registry record does not report either the primary response count or proportion, nor does it describe the analysis population or how missing assessments were handled. Therefore the endpoint's observed value, and its precision, cannot be described from the posted results. The endpoint definition clarifies what was intended to be measured; it is not itself evidence about the observed response.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical approach must be interpreted in light of what the registry record actually reports. The study is classified as single-group, with no masking and no allocation to a comparator. The primary outcome is a binary response classification: each participant either meets the complete-or-partial-response definition or does not. The record gives an endpoint definition and time point, but no estimate, interval, test, or analytic description. The following explains the relevant statistical concepts in general; it does not imply that a particular analysis was performed in this study.

What does a response proportion represent?

For a binary endpoint, a proportion describes the number of participants with the event of interest relative to the number included in the analysis. Here the event is having a best response of complete response, confirmed or unconfirmed, or partial response. The denominator matters: it might include all enrolled participants or a defined subset with adequate assessment, depending on the prespecified analysis population and missing-data rules. Those choices can affect the estimate. The registry record does not state which population was used or how unavailable assessments were classified.

A proportion is an estimate from the participants observed, rather than a guarantee of the value that would be seen in another group of similar participants. Sampling uncertainty is commonly expressed with a confidence interval. In general, a confidence interval describes a range of values compatible with the observed data under the method's assumptions; it does not remove bias from participant selection, outcome assessment, or missing data. No response estimate or confidence interval is reported in this registry record, so its magnitude and precision cannot be evaluated.

Why does the single-group design matter?

In a randomized comparative trial, allocation can support a comparison between groups by making treatment assignment independent of measured and unmeasured baseline features on average. This study has no randomized comparator. A response proportion in the treated group, even if available, would be descriptive of that group. It would not alone estimate the difference that would have occurred under an alternative treatment, nor isolate the contribution of each drug in the combination. There is no like-for-like control comparison in the registry design.

The absence of masking is also relevant in general. For outcomes that require clinical judgment, knowledge of treatment could potentially influence assessment or recording. The endpoint is described using response criteria, but the registry does not report procedures for independent review, adjudication, or blinding of assessors. It would be inappropriate to assume that any such procedure was used.

What can a confidence interval and test establish?

In general, a confidence interval around a response proportion would indicate statistical uncertainty under its calculation method. A hypothesis test, if specified, would compare the observed data with a defined null hypothesis. Neither an interval nor a p-value would establish causation in a single-group study. Statistical significance, when reported, concerns compatibility with a statistical model and a null hypothesis; it is not by itself a measure of clinical importance. The registry record does not report a hypothesis, test, confidence interval, or p-value for the primary outcome.

For an outcome based on a proportion, the precision depends on the number of participants observed and the observed frequency, as well as the method used to calculate uncertainty. The enrolled count is 30, but the number analyzed for response is not reported. It would therefore be inappropriate to infer a precision estimate from enrollment alone.

How should planning illustrations be read?

The registry record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect and that non-time-to-event illustrations are expressed as participants per arm. These are general planning assumptions, not evidence that the study was designed as a two-arm trial. They do not describe the actual single-group design, and no resulting sample-size values are stated in the registry record.

Sample-size calculations are planning exercises based on assumptions about the effect to detect, error rates, allocation, and statistical method. They are not observed power. A calculation based on an observed effect is especially distinct from prospective justification: the observed estimate can be uncertain, and using it for planning does not validate the estimate. The record does not report the trial's own sample-size justification, so no claim should be made that the enrolled count met a particular design target.

Why are analysis details important?

Interpretation also depends on prespecification and analysis conduct. Relevant details could include the primary analysis population, response-assessment timing and rules, handling of incomplete assessments, confidence-interval method, and whether analyses were adjusted. These are general methodological considerations, not analyses that can be attributed to this trial. Such details are not reported in the registry record. Without them, even a posted point estimate might require caution about denominator choice and assessment completeness; in this record, the primary estimate itself is also absent.

The registry lists 5 outcome measures and zero analyses. That supports the limited conclusion that outcome descriptions are recorded without analyses in the posted record. It does not establish whether analyses were conducted elsewhere or why they are absent. The statistical reading must therefore remain descriptive: the registry specifies what the primary endpoint was intended to measure, but supplies no primary result to quantify.

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 + Rituximab")
n      <- c(27)
events <- c(0)
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 + Rituximab  27  0  0.0  0.0  12.8  0.0  12.5  0.1  12.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 5 outcome measures, including the primary response-rate outcome and secondary outcomes concerning time to next treatment, overall survival, treatment-related adverse events, and duration of response. It reports zero analyses. A list of outcomes is not a record of which endpoints were analyzed, what estimates were produced, or how results were selected for reporting. The registry record does not describe a multiplicity strategy, such as an ordering of tests or adjustment for assessing multiple outcomes. It is therefore not possible to determine whether multiplicity was addressed or how it would affect any inferential claims.

Multiplicity is a general statistical concern when several outcomes or hypotheses are examined: the chance of at least one apparently notable result can increase with the number of tests. Methods to manage that concern depend on the questions and analysis plan. No testing plan or adjustment is reported in the registry record, and no p-values or endpoint analyses are posted. No claim about statistical significance should be inferred from outcome names alone.

Missing-data handling is also not reported. The registry does not state how participants without a response assessment were treated, whether assessment timing varied, or which participants formed the primary analysis population. These details matter because the response proportion depends on who is included in its denominator and how absent response information is handled. The enrollment count should not be substituted for an analysis denominator without that information.

Other analysis-population definitions, protocol deviations, exclusions, and sensitivity analyses are not reported in the registry record. The absence of these details does not establish that no such methods were used; it means they cannot be evaluated from the posted registry information. In this setting, the most important limitation is that neither the primary analysis nor its result is reported.

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: pancreatitis (3.3%), abdominal pain (3.3%), back pain (3.3%), bullous dermatitis (3.3%), cardiac disorders - palpitations (3.3%).

The registry records 1 serious adverse event among 30 participants at risk in the lenalidomide plus rituximab group. It also records 30 participants affected by other adverse events among 30 at risk. These are descriptive counts for the one treatment group, not estimates of excess risk relative to a control group. The registry lists pancreatitis, abdominal pain, back pain, bullous dermatitis, cardiac disorders - palpitations, and dyspnea among the top serious terms, each with a reported frequency of 3.3%.

The serious-event count and term list are not interchangeable summaries. The record does not specify whether the term frequencies refer to participants or events, whether a participant could contribute more than one term, or how the listed terms relate to the single serious adverse event count. Those details are not reported in the registry record. The term percentages should therefore be read as posted, without inferring a total number of affected participants from them.

Adverse-event interpretation also depends on definitions, follow-up duration, collection methods, and attribution rules. The registry identifies treatment-related adverse events as a secondary outcome, but does not give detailed analysis methods or a complete adverse-event profile in the information recorded. A count in a single group cannot show how the same participants would have fared under another treatment. These figures describe recorded events, not comparative safety or causation.

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

The registry record establishes the study's design and intended primary question: a Phase II, single-group assessment of lenalidomide with rituximab in previously untreated indolent non-Hodgkin's lymphoma, with response rate specified at 4 months. It records enrollment of 30 and gives a definition of complete and partial response. It also records selected adverse-event counts. These details help characterize the study being registered.

The record does not report the primary response result. No response numerator, proportion, confidence interval, or analysis is posted. It is therefore not possible to state how frequently participants met the response definition or how precisely that frequency was estimated. Nor can the outcome descriptions for time to next treatment, overall survival, or duration of response be treated as findings; their results are not reported in the registry record.

Even if a response estimate were available, the single-group design would limit what it could establish. An observed response could describe outcomes among enrolled participants, but without a concurrent randomized comparator it could not isolate the effect of the regimen from other influences. The combination design also would not separate the contribution of lenalidomide from that of rituximab. The study does not provide a like-for-like treatment comparison.

The safety counts likewise describe the treatment group rather than comparative risks. The record lists 1 serious adverse event among 30 at risk, 30 affected by other adverse events among 30 at risk, and several serious-event terms with reported frequencies of 3.3%. The information available does not give complete definitions or enough analytic detail to infer causation or compare safety with another approach.

In short, the registry record documents an intended response assessment and selected safety information, but not an efficacy estimate or comparative conclusion. The absence of a posted result is not evidence that the treatment did or did not produce responses. It means the central numerical outcome cannot be evaluated from the registry record.

14. Why This Trial Matters Statistically

This study is statistically instructive because it separates an endpoint definition from an endpoint result. The registry describes a response-rate measure in concrete terms: participants' best complete or partial response, assessed at 4 months. Yet the posted record does not report the response count, proportion, or an analysis. A well-defined endpoint is necessary for interpretation, but it cannot substitute for a numerical finding.

The single-group structure is another important feature. A treatment-group response proportion can be useful as a descriptive outcome, but it does not answer the comparative question of how outcomes differ under another treatment. Without randomized allocation to a comparator, causal interpretation is limited. This distinction matters when reading treatment studies: a result within a group is not the same quantity as a treatment effect between groups.

The registry also illustrates the need to distinguish enrollment from the analysis population. The record states enrollment of 30, but does not say how many participants were assessed for the primary outcome or how missing assessments were handled. Those details determine the denominator and help readers assess possible bias. Their absence, alongside the missing primary estimate, prevents a full statistical reading.

Finally, the record lists multiple outcomes and a planning illustration with assumptions that differ from the actual single-group design. Planning calculations are not observed evidence, and sample-size illustrations are not observed power. The trial's own sample-size justification and statistical analysis plan are not reported. These distinctions help prevent planning assumptions, outcome labels, and event counts from being misread as evidence of efficacy or as a comparative result.

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 most direct limitation of the registry information is that the primary response result is not reported. The response count, proportion, interval estimate, and analysis are absent. Although the primary endpoint is specified at 4 months, the record does not report the endpoint analysis population or how participants without an assessable response were handled. Enrollment of 30 cannot be assumed to be the response denominator.

The single-group design provides no concurrent comparator. It can support descriptive reporting of outcomes among participants who received the regimen, but it cannot make a randomized estimate of treatment differences. With lenalidomide and rituximab given together, a single-group result would also not identify the separate contribution of either drug. Masking is listed as NONE; procedures for independent response review or blinded assessment are not reported in the registry record.

The record status is TERMINATED, but the reason for termination and its effect on planned enrollment, follow-up, endpoint assessment, or analysis are not reported. The registry lists secondary outcomes without their results and records zero analyses. Definitions and methods for the secondary outcomes, analysis populations, missing-data procedures, and statistical plan are not reported. The record also does not give a trial-specific sample-size justification.

Safety information is limited to the recorded group counts and selected serious-event terms. Detailed event definitions, observation period, attribution procedures, and the relationship between individual terms and affected participants are not reported. These limitations do not establish that other information does not exist; they constrain what can be concluded from the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Lenalidomide and Rituximab in Subjects With Previously Untreated Indolent Non-Hodgkin's Lymphoma — NCT01316523.
• Registry record last updated 2025-11-21; status last verified 2025-11.
• Results first posted 2025-11-21.
• 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.

19. Record Summary

NCT01316523 is a Phase II, single-group study of lenalidomide and rituximab in previously untreated indolent non-Hodgkin's lymphoma, sponsored by the University of California, Davis. Enrollment was 30; the registry lists status as TERMINATED, start as 2010-12, and primary completion as 2023-09-12. The study was unmasked and had no comparator group.

The primary outcome was the proportion with best response of complete response, confirmed or unconfirmed, or partial response, assessed at 4 months. The registry record does not report the response result or an analysis. It lists secondary outcomes concerning time to next treatment, overall survival, treatment-related adverse events, and duration of response. Safety records include 1 serious adverse event among 30 at risk and 30 affected by other adverse events among 30 at risk. The registry does not report the reason for termination, trial-specific sample-size justification, analysis populations, or missing-data methods.