Lirilumab With Rituximab for Relapsed, Refractory or High-risk Untreated Chronic Lymphocytic Leukemia (CLL) Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lirilumab With Rituximab for Relapsed, Refractory or High-risk Untreated Chronic Lymphocytic Leukemia (CLL) Patients (NCT02481297), a non-randomized phase 2 study. The primary outcome is Participants With a Response.

2. Clinical Question

The study asked whether lirilumab combined with rituximab could help control chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), while also examining the safety of the combination. It included two distinct clinical groups: participants whose disease was refractory or had relapsed after prior therapy, and untreated participants with high-risk molecular features. The study was not randomized, and the two cohorts do not constitute a like-for-like treatment and control comparison.

3. Trial Design

This was a Phase 2, parallel, non-randomized study with no masking. The registry lists enrollment of 7 and a completed study. The recorded start date is 2015-06-23, and the primary completion date is 2019-08-15. M.D. Anderson Cancer Center is listed as the sponsor.

The study organized participants into two cohorts. Cohort 1 included people with refractory or relapsed CLL after prior therapy. Cohort 2 included untreated people with high-risk molecular features. Both cohorts received the same described combination regimen, but they differed in disease history and treatment status. Because participants were not randomized between these groups, and there is no listed control arm, the cohorts are not a like-for-like comparison. Differences between them could reflect their differing clinical characteristics rather than treatment effects.

In both cohorts, rituximab was given intravenously at 375 mg/m2 weekly for the first 4 weeks, on Days 1, 8, 15, and 22, and then at the start of each course. Lirilumab was given intravenously at 3 mg/kg on Day 1 of each cycle. Rituximab was given for the first 12 cycles, while lirilumab could continue for up to 24 cycles. Each cycle was 4 weeks. These descriptions establish the planned regimen in the registry; information about actual treatment received, adherence, dose modifications, and reasons for stopping is not reported in the registry record.

The primary outcome was participants with a response during the first 6 months. Overall survival and progression-free survival are listed as secondary outcomes. The registry record lists three outcome measures and no analysis entries. Results for the listed efficacy outcomes are not reported in the registry record, so the design and endpoint definitions can be described, but the treatment outcomes cannot be quantified from this 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 Participants With a Response, measured over 6 months.

The primary endpoint counts participants who achieved a specified response during the first 6 months of therapy. The response categories are complete remission (CR), complete remission with incomplete marrow recovery (CRi), and partial remission (PR). The endpoint is a binary participant-level outcome: a participant either meets the response definition during the stated period or does not. The registry identifies the measure as a count of participants, but the response count is not reported in the registry record.

The definition of CR includes absence of peripheral blood clonal lymphocytes by immunophenotyping, lymphadenopathy, hepatomegaly or splenomegaly, and constitutional symptoms, together with satisfactory blood counts. CRi is described as complete remission with incomplete bone marrow recovery. PR requires a 50% or greater fall in lymphocyte count, a 50% or greater reduction in lymphadenopathy, or a 50% or greater reduction in liver or spleen, together with improvement in peripheral blood counts.

General statistical context: a response endpoint can summarize whether participants reached a clinically defined state within a specified period. A count alone does not show how uncertain the underlying response rate is; interpretation also depends on the number assessed and the analysis method. The registry does not report a response estimate, confidence interval, or analysis for this endpoint. The definition therefore clarifies what would count as a response, but it does not establish how many participants responded.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a non-randomized, unmasked, parallel Phase 2 study. It lists a primary participant-count outcome and two secondary time-to-event outcomes, overall survival and progression-free survival. No analysis entries are listed. The record does not describe the statistical methods used to analyze these outcomes. The explanations below describe general statistical concepts and are not claims about analyses performed in this study.

What does a participant-count endpoint represent?

For a binary outcome such as whether a participant met a response definition within a specified period, the basic data distinguish participants who met the definition from those who did not. A count describes how many participants had the event. An estimated response proportion would relate that count to the number assessed, but the registry does not report either the response count or the number assessed for this endpoint. No response proportion should therefore be inferred.

General statistical context: estimates from binary outcomes are often accompanied by confidence intervals. A confidence interval conveys uncertainty in an estimate under the assumptions of the method used; it is not a guarantee that the true value lies within a particular interval. The width depends in part on the amount of information in the data. The registry record does not report a confidence interval or an analysis method for the primary response outcome.

Why does the study design matter?

Random assignment is one way to make treatment groups comparable, on average, with respect to both known and unknown factors. This study was not randomized. Its two cohorts were defined by different clinical circumstances: prior treatment and refractory or relapsed disease in one cohort, and untreated disease with high-risk molecular features in the other. Because group membership was not assigned at random, a difference in outcomes between the cohorts would not isolate a treatment effect. Further, both cohorts received the combination regimen, so the design does not offer a listed untreated or alternative-treatment control group.

General statistical context: observational differences between groups can be affected by confounding, where a factor related to group membership is also related to the outcome. Adjustment methods can sometimes address measured differences, but they cannot automatically remove unmeasured confounding. The registry does not report an adjusted analysis or covariates used in any such analysis. With no analysis entries, no adjustment can be attributed to this study.

How should survival outcomes be understood?

Overall survival and progression-free survival are time-to-event outcomes. They concern the time until a defined event, and analyses commonly account for participants whose event has not occurred by the last available observation. General statistical context: these participants may be censored, meaning their event time is only known to exceed their observed follow-up time. Interpretation depends on the event definitions, follow-up, censoring rules, and analysis method. Those details and the survival results are not reported in the registry record.

For time-to-event analyses, a summary such as a hazard ratio would require both outcome data and a specified analysis. The registry record does not report such an estimate. The sample-size description associated with planning illustrations distinguishes total event counts for time-to-event outcomes from participants per arm for other outcomes. No numerical planning illustration is reported in the record, and no illustration should be treated as a result from this study.

What do planning assumptions mean?

General statistical context: a planning calculation estimates the amount of information that might be needed to detect a chosen effect under stated assumptions. The registry’s planning description refers to a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect expressed as a stated fraction of an observed effect. These are assumptions for an illustration, not evidence that the study used that design or achieved a particular level of power. The record does not report the trial’s own sample-size justification, the numerical planning results, or an observed effect estimate for the primary endpoint.

A sample-size illustration is not observed power. Observed power is not a substitute for reporting the estimated effect and its uncertainty. If an illustration is based on an observed effect, it is conditional on that estimate and does not establish that the effect is reliable or that a future study will reproduce it. The registry’s description characterizes the illustrations as planning calculations, not as the trial’s design rationale.

Why does over-dispersion matter?

General statistical context: over-dispersion occurs when count data vary more than a model assumes. If it is ignored, uncertainty estimates can be too small, making results appear more precise than warranted. This study’s primary endpoint is described as a participant count, but the registry does not report a model, dispersion estimate, or analysis method. There is no basis in the registry record for saying that over-dispersion was assessed or that a particular count model was used.

In sum, the registry identifies the outcomes and describes planning assumptions, but it does not provide the outcome analyses needed to assess effect estimates, their precision, or model assumptions. Statistical concepts explain what such analyses would mean generally; they do not fill in results absent from 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("Cohort 1: Refractory/Relapsed After Prior Therapy", "Cohort 2: Untreated With High-rRisk mMolecular Fea")
n      <- c(1, 6)
events <- c(0, 3)
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  Cohort 1: Refractory/Relapsed After Prior Therapy  1  0  0.0  0.0  97.5  0.0  79.3  1.3  84.2
ARM  Cohort 2: Untreated With High-rRisk mMolecular Fea  6  3  50.0  11.8  88.2  18.8  81.2  18.4  81.6

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary response outcome and secondary outcomes of overall survival and progression-free survival. It does not report a multiplicity strategy, such as a prespecified hierarchy or adjustment for testing multiple outcomes. The registry record also does not report the number of statistical tests, p-values, confidence intervals, or analysis results. It is therefore not possible to assess how multiple outcomes or comparisons were handled.

General statistical context: when several hypotheses are tested, the chance of at least one apparently notable result can increase. A prespecified testing strategy can help clarify which outcomes are confirmatory and how evidence across tests should be interpreted. The absence of a described strategy means no particular approach should be assumed.

Missing-data methods are also not reported in the registry record. The record does not state how missing response assessments, incomplete follow-up, treatment discontinuation, or unavailable measurements were handled. For the time-to-event outcomes, censoring definitions and rules are not reported. The record does not identify an intention-to-treat, per-protocol, or other analysis population. These omissions make it unclear which participants would have contributed to each outcome analysis.

General statistical context: missing observations can affect an estimate if the likelihood of missingness is related to participant characteristics or outcomes. Different assumptions and methods can lead to different estimates. Without the number assessed, the reasons data were missing, and the handling approach, the potential impact cannot be evaluated. No particular missing-data problem or remedy can be inferred from the registry record.

The registry lists enrollment of 7, but the analyzed population for the primary endpoint and secondary outcomes is not reported. Enrollment alone does not establish that every participant was evaluable for every outcome. The record therefore does not support a detailed assessment of analysis populations, missingness, or multiplicity.

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: pain (100.0%), fever (33.3%).

The registry lists safety counts separately for the two cohorts. For Cohort 1, the serious-event figures list 1 participant at risk and 1 affected; the other-event figures also list 1 at risk and 1 affected, with 0 deaths. For Cohort 2, the serious-event figures list 6 at risk and 2 affected; the other-event figures list 6 at risk and 6 affected, with 1 death. These are descriptive registry counts, not comparisons from a randomized safety analysis.

The listed top serious-event terms are Pain at 100.0% and Fever at 33.3%. The registry does not report the denominator or further event-level context for these percentages in the information available. They should not be read as percentages of all enrolled participants unless the applicable denominator is established. The record also does not report whether events were considered related to treatment, their timing, severity grading details, or whether participants could contribute more than one event.

General statistical context: safety counts are most informative when interpreted alongside the number exposed, definitions of the event categories, follow-up duration, and event attribution. Small risk sets make descriptive estimates particularly sensitive to individual observations. These entries do not establish that treatment caused an event, and the cohort counts should not be contrasted as though participants had been randomized between treatments.

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

The registry record establishes that a completed Phase 2 study evaluated lirilumab with rituximab in two non-randomized CLL cohorts. It specifies a response endpoint based on CR, CRi, or PR during the first 6 months, and it lists overall survival and progression-free survival as secondary outcomes. It also describes the intravenous treatment schedules and provides selected safety counts.

Those details do not reveal the observed response result. The primary response count, a response proportion, and an uncertainty estimate are not reported in the registry record. Results for the secondary survival outcomes are also not reported. Without these outcomes, the degree of disease control observed in the study cannot be quantified from the record.

The design does not provide a randomized comparison. Both cohorts received the combination, and their membership reflected different disease histories and risk features. The record therefore does not establish what would have happened to comparable participants under another treatment or without the combination. Nor can differences between cohorts be attributed to treatment, given their distinct clinical profiles and the absence of random assignment.

The safety counts show how the registry records affected participants and deaths within the stated risk groups. They do not, on their own, identify causality or allow a balanced comparison of harms. The limited context for the listed event percentages further constrains interpretation.

General statistical context: a study’s completion status and a defined outcome do not substitute for outcome estimates. Sound interpretation requires the observed data, the analysis population, and an account of uncertainty and missing observations. Those elements are not reported for the efficacy outcomes in the registry record. Thus, the information supports a description of what the study set out to assess, but not a conclusion that the combination did or did not produce a particular treatment effect.

14. Why This Trial Matters Statistically

This study is statistically notable because it illustrates the distinction between a clinical question and an estimable treatment comparison. The stated aim concerned control of CLL or SLL with lirilumab and rituximab, but the design was non-randomized and contained two clinically different cohorts rather than a like-for-like control group. The results, even if available, would need to be interpreted as observations from those cohorts rather than as a randomized estimate of comparative benefit.

The primary outcome is defined in clinically detailed terms, combining CR, CRi, and PR within the first 6 months. Clear endpoint definitions are important because a response count depends on which criteria are applied and the time period considered. Yet the definition alone cannot answer how many participants responded. The response result and its uncertainty are not reported in the registry record.

The registry lists overall survival and progression-free survival as secondary outcomes, which are conceptually different from a response count because they concern time to events and follow-up. Their interpretation would depend on event definitions, censoring, and analysis methods, none of which are reported with outcome results. This makes the record a useful example of why an outcome list should not be confused with a completed statistical report.

The enrollment of 7 also makes transparent reporting of denominators, participant flow, and uncertainty important. The safety entries provide some counts, but not enough context to establish attribution or compare risks causally. Together, these features show why design, outcome availability, and analysis details all matter when evaluating a small clinical study. The record documents the study framework, while leaving its efficacy estimates and analysis strategy unreported.

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 is that the registry record does not report the primary response count or statistical analysis. It also does not report results for overall survival or progression-free survival. Consequently, efficacy estimates, precision, and outcome patterns cannot be assessed from the record.

The study was non-randomized and had no listed control group. Its two cohorts represented different clinical situations, so any comparison between them would be vulnerable to differences in disease history and risk features. The cohorts cannot serve as a like-for-like treatment comparison, and no causal treatment contrast is identified.

The overall enrollment was 7. The registry does not report the number assessed for each efficacy outcome, participant flow, or the analysis populations. Eligibility details beyond the cohort descriptions, baseline characteristics, follow-up completeness, and reasons for treatment discontinuation are not reported in the registry record. These omissions limit assessment of who contributed data and how representative the analyzed participants may have been.

Statistical-plan details are also absent. The registry does not report a sample-size justification for the trial, a multiplicity strategy, missing-data methods, adjustment variables, or methods for the secondary survival outcomes. The planning description is an illustration and does not establish the trial’s original design rationale.

Safety information is limited to selected counts and listed serious-event terms. Event definitions, attribution, timing, and denominator context for the listed percentages are not reported. The safety data therefore support only a cautious descriptive reading, not a causal conclusion about treatment-related harm.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Lirilumab With Rituximab for Relapsed, Refractory or High-risk Untreated Chronic Lymphocytic Leukemia (CLL) Patients — NCT02481297.
• Registry record last updated 2020-05-28; status last verified 2020-05.
• Results first posted 2020-05-26.
• 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, non-randomized Phase 2 study sponsored by M.D. Anderson Cancer Center. It enrolled 7 participants and evaluated intravenous lirilumab with rituximab in cohorts defined by refractory or relapsed disease after prior therapy, or untreated disease with high-risk molecular features. The record gives the regimen and defines response as CR, CRi, or PR during the first 6 months.

Overall survival and progression-free survival are listed as secondary outcomes. The registry record lists three outcome measures and no analysis entries. It does not report the primary response result or secondary efficacy results. Safety entries include cohort-specific risk and affected counts, deaths, and listed serious-event terms, but event context and attribution are limited. The record supports a description of the study design and endpoints, not a quantitative assessment of treatment efficacy or a randomized comparison.