Rituximab, Alemtuzumab, and GM-CSF As First-Line Therapy in Treating Patients With Early-Stage Chronic Lymphocytic Leukemia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Rituximab, Alemtuzumab, and GM-CSF As First-Line Therapy in Treating Patients With Early-Stage Chronic Lymphocytic Leukemia (NCT00562328), a na phase 2 study. The primary outcome is Number of Confirmed Responses (Complete or Partial Response Noted as the Objective Status for a Duration of at Least 2 Months) at 6 Months.

2. Clinical Question

3. Trial Design

This was a phase II clinical trial of alemtuzumab, rituximab and GM-CSF as initial treatment for early-stage chronic lymphocytic leukemia. The registry lists a single-group model, allocation as not applicable, and masking as none. The intervention arm is named Alemtuzumab + Rituximab + GM-CSF. No separate control or comparator arm is listed, so the design is not a randomized comparison.

The registry records enrollment of 33 and a status of completed. The recorded start is 2008-01, and primary completion is dated 2010-02-05. These dates and the enrollment describe the registered study; the record does not establish from these details alone how many participants were eligible, treated, assessed at the primary time point or included in an analysis.

The stated purpose was to study side effects and assess the regimen in patients with early-stage chronic lymphocytic leukemia. The primary outcome was the number of confirmed complete or partial responses at 6 months, requiring the response to persist for at least 2 months. Secondary outcomes listed in the record are progression-free survival, duration of response, time to next treatment and overall survival. Although the record lists five outcome measures, it does not report results for those outcomes in the registry record for this analysis.

Details needed to reconstruct conduct and analysis—including eligibility criteria, treatment schedule, follow-up procedures and analysis populations—are not reported in the registry record. The registry record also does not report a protocol justification for the enrollment target or the statistical analysis plan. The design description therefore supports a limited account of the study structure, not a detailed assessment of how participants were selected, treated or analyzed.

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: All patients were deemed eligible.

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 Number of Confirmed Responses (Complete or Partial Response Noted as the Objective Status for a Duration of at Least 2 Months) at 6 Months, measured over 6 months.

The primary endpoint counts participants whose best objective status was a confirmed complete or partial response at 6 months. The response had to be sustained for at least 2 months. The registry defines these responses using National Cancer Institute Working Group criteria. Complete response requires specified clinical and blood-count findings, with confirmation by bone marrow aspirate and biopsy. Partial response requires improvement in specified disease measures together with improvement in at least one of several blood-count measures. The detailed criteria matter because the endpoint is not simply a clinician’s general impression of improvement.

A response count is a binary-outcome summary: each participant is classified according to whether the defined response occurred or did not occur, and the endpoint reports the number meeting the response definition. Such an endpoint can make a treatment study’s short-term disease response explicit and reproducible when the criteria and assessment time are defined. Requiring confirmation and a minimum duration is intended to distinguish a sustained response from an unconfirmed or brief change.

The registry names the assessment time as 6 months, but it does not report the observed number of confirmed responses, the number assessed at that time, or an uncertainty interval. Thus, the endpoint’s definition can be described, but its observed value and precision cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the single-group design permit?

In a single-group study, participants receive the intervention under study, and outcomes are described for that group. Because the record lists no separate comparator, there is no concurrent control group against which to estimate a treatment contrast. A statistical summary of outcomes in the treated group can describe the observed experience, but it cannot isolate the effect of treatment from other influences. This is a general interpretation of single-group designs, not a claim about an unreported analysis in this trial.

The registry lists allocation as not applicable and masking as none. Those design labels do not supply further information about enrollment procedures, assessment processes or outcome adjudication. Such details are not reported in the registry record.

How should the response endpoint be understood?

The primary endpoint is a count of participants meeting the prespecified response definition at 6 months, with response required to persist for at least 2 months. A count is an absolute summary, not a comparison between treatment groups. In general, a binary response endpoint classifies each participant as meeting or not meeting the criterion. To interpret the count fully, a reader would need the number assessed and the rule used for participants whose response status was unknown. Those details and the observed count are not reported in the registry record.

General statistical reporting for a binary endpoint may include an estimated response proportion and a confidence interval. A confidence interval expresses the uncertainty associated with an estimate under the statistical method used; it is not a guarantee that the true value lies within the interval. No response estimate, confidence interval or statistical method for the primary endpoint is reported in the registry record, so none can be interpreted for this study.

What do the registry’s analysis entries establish?

The record lists 0 analyses. This does not describe an inferential result, and it does not establish which methods may have been used outside the information recorded in the registry. The analysis plan, including any model, test, adjustment, confidence-interval method or handling of repeated assessments, is not reported in the registry record. A reader should not infer those methods from the phase, endpoint name or study purpose.

There are five outcome measures listed, including the primary response measure and secondary outcomes of progression-free survival, duration of response, time to next treatment and overall survival. Naming outcomes does not show whether or how each was analyzed. The record does not provide numerical efficacy results or the methods needed to assess their precision.

What does over-dispersion mean in general?

Over-dispersion is a general concern for count data when observed variability is greater than a model assumes. If a count model assumes less variability than is present, uncertainty estimates can be too narrow and tests can overstate precision. This concept does not establish that over-dispersion occurred in this trial. The primary endpoint is described as a participant count, but a count alone does not indicate that a count-regression model was used. The registry record does not report such a model or any assessment of over-dispersion.

How should planning illustrations be read?

Any sample-size illustrations associated with this study are planning illustrations computed from the observed effect, not the trial’s original design. The stated assumptions are 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. For time-to-event outcomes, the illustration concerns the total number of events; for other outcomes, it concerns participants per arm. These are hypothetical planning assumptions, not evidence that the study used a two-arm design, and not observed power. The actual trial is registered as single group, with allocation not applicable. The trial’s own sample-size justification is not reported in the registry record.

General planning calculations answer a different question from an outcome analysis. They explore what a future study might require under explicit assumptions; they do not substitute for an observed estimate and its uncertainty. No numerical illustration values are described in the registry entries used for this account, and no new sample-size calculation is appropriate from the available information.

Finally, statistical interpretation depends on both the endpoint definition and the analysis population. The registry record does not report how missing assessments were handled, whether all enrolled participants were analyzed, or whether the primary endpoint was analyzed in another specified population. These omissions prevent assessment of potential bias from missing outcome data or from differing analysis sets.

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("Alemtuzumab + Rituximab + GM-CSF")
n      <- c(33)
events <- c(31)
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  Alemtuzumab + Rituximab + GM-CSF  33  31  93.9  79.8  99.3  80.4  98.3  80.3  98.1

11. Multiplicity, Missing Data and Analysis Populations

The record lists five outcome measures: the primary confirmed-response count at 6 months and secondary outcomes of progression-free survival, duration of response, time to next treatment and overall survival. When several outcomes are considered, general statistical practice recognizes a multiplicity issue: the chance of at least one apparently notable finding can rise when many hypotheses are tested. Possible approaches include identifying a primary outcome in advance, adjusting inference across selected tests, or treating secondary findings as exploratory. The registry record does not report a multiplicity strategy, testing hierarchy or adjustment method. It is therefore not possible to determine how multiple outcomes were handled.

The record lists 0 analyses, and no statistical analysis plan is reported. Interim analyses, stopping rules and any adjustment associated with repeated looks at accumulating results are not reported in the registry record. No interim-analysis procedure should be inferred from the study’s phase or status.

Missing-data handling is also not reported in the registry record. In general, missing outcome assessments can affect a binary response count if participants without an assessment are excluded, counted as nonresponders or handled using another method. These choices can lead to different interpretations. The registry entries do not say which approach, if any, was used. The number assessed at the primary time point and the analysis population are likewise not reported.

These gaps matter because an endpoint’s definition does not fully specify its analysis. Without the analysis population, missing-data rules and multiplicity approach, readers cannot reconstruct the inferential framework or judge how it may affect reported uncertainty. No adjustment or missing-data method should be attributed to this trial based on the available registry record.

12. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumonia (3.0%), dyspnea (3.0%).

The registry lists 1 participant affected in the serious adverse-event category, with 33 at risk. In the other adverse-event category, it lists 33 affected, with 33 at risk. These are the recorded counts for the single named intervention group, Alemtuzumab + Rituximab + GM-CSF. The categories should be read as registry entries, not as a comparison between treatment groups.

Pneumonia and dyspnea are listed among the top serious terms, each with 3.0%. The record does not specify in these details the percentage denominator, event timing, severity grade, duration, relationship to treatment or whether an individual could contribute more than one event. It is therefore not appropriate to infer those features from the term and percentage alone. The deaths entry is null; deaths are not reported in the registry record.

These safety figures do not establish comparative risk or causation. The study has no separate control group, and the registry entries do not describe an attribution method. The figures indicate what was recorded in the stated categories, while the missing context limits further interpretation.

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

The record establishes that a phase II, single-group study evaluated a combination of alemtuzumab, rituximab and GM-CSF as initial therapy for early-stage chronic lymphocytic leukemia. It specifies a primary endpoint: the number of confirmed complete or partial responses at 6 months, with a response sustained for at least 2 months. It also lists four secondary outcomes and selected adverse-event entries. These design and endpoint details clarify what the study set out to assess.

The record does not report the observed primary response count, the number assessed at the primary time point, an efficacy estimate or its uncertainty. Therefore, it does not support a conclusion about the frequency of response in the enrolled group. The absence of those results should not be interpreted as a zero response count or as a positive result. It means the outcome cannot be evaluated using the registry entries.

Even if a response count were available, the single-group design would describe outcomes in the treated group rather than provide a randomized comparison. It could not by itself show how outcomes differed from those under another treatment or from outcomes without the intervention. This is a general design limitation and does not determine what an unreported comparative study might find.

The safety entries report serious and other adverse-event categories, with pneumonia and dyspnea among the top serious terms. The information does not specify enough detail to assess event attribution, timing or comparative safety. Deaths are not reported in the registry record. Thus, the entries should be read as registry descriptions rather than as a complete evaluation of safety.

In short, the record supports an account of study design, outcome definitions and selected safety reporting, but not a conclusion about efficacy or comparative safety. The statistical meaning of the intended primary endpoint is clear; its observed value and precision are not reported.

14. Why This Trial Matters Statistically

This trial is statistically instructive because it separates an endpoint’s definition from its result. The registry gives a detailed response definition, assessment time and minimum duration, but the observed response count is not reported in the registry record. Without the result and its denominator, the endpoint cannot answer how frequently the defined response occurred in this group.

The design is also important to interpretation. A single-group phase II study can describe outcomes among participants receiving the combination, but does not create a randomized contrast. This distinction matters whenever a result is discussed: a within-group observation and a treatment effect relative to a comparator are different statistical quantities. The record lists no comparator and allocation as not applicable.

The listed secondary outcomes raise general questions about multiplicity, outcome definitions and analysis plans. Several outcomes can provide a broader view of what a study intended to assess, but they also require transparent reporting of which analyses were performed and how conclusions were framed. The registry lists five outcome measures and 0 analyses; the statistical methods and numerical results are not reported in the registry record.

The safety entries illustrate why raw counts and percentages need context. The registry reports affected counts and at-risk counts for two categories and gives percentages for top serious terms, but details such as event timing, attribution and the percentage denominator are not stated in the available record. Statistical interpretation should reflect those limits rather than treating a sparse listing as a complete safety comparison.

For clinical researchers, the central lesson is that a registered study question, a defined endpoint, and an observed statistical result are not interchangeable. Clear endpoint criteria improve interpretability, while complete outcome and analysis reporting is needed to evaluate magnitude and precision. This record makes the intended question visible but does not provide the primary outcome result needed to answer it.

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 principal limitation for interpreting the study is that the registry entries do not report the observed primary response count. The number assessed at 6 months, the analysis population and the handling of missing response assessments are also not reported in the registry record. Consequently, the primary endpoint cannot be quantified or checked against its stated response definition from these details.

The design is single group, with no separate comparator listed. Any outcome description would therefore lack a concurrent randomized contrast. The record lists allocation as not applicable and masking as none. Further details about eligibility, outcome assessment, treatment delivery and confirmation procedures are not reported in the registry record, beyond the response criteria themselves.

The registry names progression-free survival, duration of response, time to next treatment and overall survival as secondary outcomes, but their numerical results and analysis details are not reported. The record lists five outcome measures and 0 analyses. A statistical analysis plan, multiplicity strategy, interim analyses, stopping rules and missing-data methods are not reported in the registry record. The sample-size justification for the trial itself is also not reported.

Safety interpretation is limited by the lack of details on event timing, severity grading, attribution and the percentage denominator for the serious terms. The deaths entry is null, so deaths are not reported in the registry record. These limitations restrict conclusions about both outcome precision and safety context; they do not imply that unreported events or analyses did or did not occur.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Rituximab, Alemtuzumab, and GM-CSF As First-Line Therapy in Treating Patients With Early-Stage Chronic Lymphocytic Leukemia — NCT00562328.
• Registry record last updated 2020-04-08; status last verified 2017-05.
• Results first posted 2012-05-08.
• 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

NCT00562328 is a completed phase II, single-group study sponsored by Mayo Clinic. Its recorded start is 2008-01 and primary completion is 2010-02-05; enrollment is listed as 33. The intervention was alemtuzumab, rituximab and GM-CSF, with sargramostim listed for GM-CSF. Allocation is not applicable and masking is none.

The primary outcome was the number of confirmed complete or partial responses at 6 months, with response required to last at least 2 months and defined using National Cancer Institute Working Group criteria. Secondary outcomes listed are progression-free survival, duration of response, time to next treatment and overall survival. The observed primary response count and numerical secondary results are not reported in the registry record. The record lists 0 analyses.

Safety entries list 1 affected in the serious category and 33 affected in the other category, each with 33 at risk. Pneumonia and dyspnea are listed as top serious terms, each with 3.0%. Deaths are not reported in the registry record.