Ofatumumab With High Dose Methylprednisone Followed by Ofatumumab and Alemtuzumab in 17p CLL: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ofatumumab With High Dose Methylprednisone Followed by Ofatumumab and Alemtuzumab in 17p CLL (NCT01465334), a non-randomized phase 2 study. The primary outcome is Induction Overall Response Rate (ORR).

2. Clinical Question

The clinical question is whether this sequential treatment strategy was associated with an objective response among participants with 17p deletion CLL, and how the response experience differed descriptively between those with and without prior CLL treatment. The design can describe outcomes within each prior-treatment group, but it cannot establish that any difference between groups was caused by treatment history. Prior treatment status was not assigned at random and may be associated with other differences among participants.

The study describes a treatment sequence rather than a comparison of individual drugs. The registry’s summary states that participants received ofatumumab and HDMP first, followed by ofatumumab and alemtuzumab. It does not provide reported primary response counts, percentages or confidence limits. Consequently, the central efficacy question cannot be answered from the registry record alone. The endpoint definition and assessment schedule indicate what investigators intended to measure, but do not establish how many participants responded or how precisely any response rate was estimated.

3. Trial Design

This was a Phase II, non-randomized, parallel-group study with no masking. The registry lists enrollment of 30. The two groups were defined by prior treatment status: Treatment Naive and Relapsed/Refractory. Participants were assigned to one of those groups based on that status, not by random allocation. Both groups received the same described therapy, so the grouping supports a descriptive comparison of populations with different treatment histories rather than a randomized treatment comparison.

The stated sequence began with Induction Part A, ofatumumab plus HDMP, for 2-4 cycles. The cycle duration was 28 days. The arm descriptions begin to specify ofatumumab dosing in cycle 1, but the registry text is incomplete after describing the first cycle and the beginning of cycles 2-4. The full dosing schedule cannot therefore be reconstructed from the record. The later sequence is described as ofatumumab plus alemtuzumab, but its detailed schedule is not reported in the registry record.

The primary completion date is 2014-11 and the start date is 2011-12. The study status is Terminated. The reason for termination and the timing of the termination are not reported in the registry record; the status alone does not explain whether planned recruitment, follow-up or analyses were completed.

Response assessment was scheduled after weeks 8 and 16 of Part A and at 12, 18 and 24 weeks during Part B. The registry lists secondary outcomes that include response measures, minimal residual disease, transplant rate, hyperglycemia during Part A induction, and 3-year progression-free and overall survival probabilities. The record does not provide results for these outcomes. Nor does it report a randomization scheme, masking procedures, a control regimen or a statistical analysis plan. Those omissions limit interpretation of how the study was intended to distinguish treatment effects from other influences.

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

Reasons for not completing this period:

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: The analysis dataset is comprised of all treated participants.

6. Primary Endpoint

The registry lists the primary outcome as Induction Overall Response Rate (ORR), measured over Disease was evaluated after weeks 8 and 16 of Part A and at 12, 18 and 24 weeks during part B..

The primary endpoint was Induction Overall Response Rate (ORR), defined as the percentage of participants achieving at least a partial response over induction treatment. The stated response criteria were based on International Workshop on Chronic Lymphocytic Leukemia criteria. Partial response required specified changes from baseline in measured lymphadenopathy, liver and spleen enlargement, blood lymphocytes, marrow findings and blood-cell measures. The registry description includes thresholds for decreases in disease measures and increases in platelet count, hemoglobin and neutrophils.

An objective response endpoint gives a structured way to describe whether disease measurements meet prespecified response criteria. It combines multiple clinical and laboratory assessments rather than relying on a single measurement. The registry lists blood counts and differential, marrow aspirate and biopsy, abdominal ultrasound, CT scans of the chest, pelvis and abdomen, and physical examination as tests that may be used in response evaluation. The description says these assessments are potentially used; it does not establish that every test was performed for every participant.

The endpoint is reported as a percentage, with a 90% confidence interval specified as its dispersion measure. A confidence interval communicates uncertainty around an estimated response percentage: wider intervals generally indicate less precision, while narrower intervals indicate greater precision, under the assumptions of the analysis. However, the registry record does not report the observed percentage, its interval, the number assessed or the analysis population. The assessment schedule is described, but the primary endpoint results are not reported in the registry record.

Response rate is not the same as duration of response, progression-free survival or overall survival. Those are distinct outcomes, and the registry lists some time-to-event outcomes separately. The primary endpoint therefore addresses whether participants met response criteria during induction; it does not by itself describe how long a response lasted or establish a comparative treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study design determines which conclusions can be supported. This was a non-randomized, parallel-group Phase II study. Participants were placed in the Treatment Naive or Relapsed/Refractory group according to prior treatment status. Both groups received the same described treatment sequence. Therefore, comparisons between the groups are observational: they describe outcomes in two populations, not the causal effect of assigning one treatment rather than another. Differences between groups could arise from treatment history or other participant characteristics, as well as from random variation.

What a confidence interval would convey

The primary endpoint specifies a 90% confidence interval for the response percentage. In general, 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 in a particular interval, and its interpretation depends on the method and assumptions. A confidence interval around a percentage is especially relevant when the number of participants is limited, because a small amount of outcome variation can have a substantial influence on the estimate. The actual response estimate and interval are not reported in the registry record, so their precision cannot be evaluated.

Why the response definition matters

Response was based on International Workshop on Chronic Lymphocytic Leukemia criteria, with partial response defined through changes in several disease measures and blood-cell results. Standardized criteria can make response classification more consistent than an informal judgment, but the registry description does not report how assessments were adjudicated, whether review was independent, or how missing or conflicting measurements were handled. It lists multiple possible diagnostic tests, including blood testing, marrow assessment, imaging and physical examination. The record does not say which tests were available for each participant or how incomplete assessments were incorporated.

Reading a percentage endpoint

A response rate is a binary-outcome summary at the participant level: each participant is classified according to whether the response definition was met for the analysis. The rate depends on both the number meeting the definition and the population counted in the denominator. A clearly defined denominator is therefore essential. The registry identifies the endpoint unit as a percentage of participants but does not report the denominator, response count, or analysis population. It is not possible to reconstruct or verify the primary estimate from the information in the record.

Response rates do not capture how long a response lasts. The separate progression-free and overall survival outcomes address different questions and ordinarily require information about event timing and follow-up. The registry lists 3-year probabilities for those outcomes, but does not report estimates or describe the analytic procedures used to obtain them. No survival method, censoring convention or follow-up completeness is reported in the registry record.

What the design permits

Non-random allocation means that the groups may differ before treatment begins. In a randomized trial, random allocation is intended to balance measured and unmeasured prognostic characteristics on average. That protection is not present. Even if group-specific response results were available, a difference between the groups could not be interpreted as the effect of prior treatment status or as evidence that the regimen works differently by treatment history without additional assumptions and analyses. The registry record does not report adjusted comparisons or a model addressing confounding.

The record also does not report a statistical analysis plan, hypothesis-testing procedure, interim analysis plan, missing-data approach or methods for handling multiple outcomes. These are not details that can be inferred from the phase or the endpoint description. The absence of reported analyses means there is no documented sponsor analysis to interpret for the primary endpoint. There are no analyses listed in the record.

Over-dispersion and binary outcomes

In general, over-dispersion means that observed variation is greater than a statistical model expects. It can arise when outcomes vary more across participants or groups than a simple model assumes. Recognizing over-dispersion may matter for uncertainty estimates, because an analysis that understates variation can produce confidence intervals that are too narrow. This is a general statistical consideration, not a reported feature or method of this study. The registry record does not describe an over-dispersion assessment or a model for the primary endpoint.

The registry includes a sample-size illustration methodology based on the observed effect, a two-sided significance level of 0.05, equal allocation, a normal approximation, and effects expressed as a stated fraction of the observed effect. Such illustrations are planning calculations rather than observed trial results or observed power. The record does not report the resulting sample-size values in the registry record for this analysis, and it does not state that these assumptions formed the trial’s original design justification. The trial’s own sample-size justification 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("Treatment Naive", "Relapsed/Refractory")
n      <- c(15, 15)
events <- c(11, 9)
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  Treatment Naive  15  11  73.3  44.9  92.2  48.0  89.1  47.6  89.0
ARM  Relapsed/Refractory  15  9  60.0  32.3  83.7  35.7  80.2  35.4  80.2

11. Multiplicity, Missing Data and Analysis Populations

The registry names a primary endpoint and several secondary outcomes. These include response measures, minimal residual disease negativity, transplant rate, treatment-related hyperglycemia during Part A induction, and 3-year progression-free and overall survival probabilities. When several outcomes are examined, the chance of at least one apparently notable result can increase if each is tested separately without accounting for multiplicity. General approaches include prioritizing a primary endpoint, specifying a testing sequence, or adjusting inference across outcomes. The registry record does not report a multiplicity strategy or a statistical analysis plan, so it is not possible to determine whether or how multiple outcomes were accounted for.

The record lists no analyses and does not report primary or secondary outcome estimates. It also does not describe an analysis population, such as whether participants were analyzed according to enrollment, treatment received, or availability of an endpoint assessment. The number who began treatment, completed the induction assessments, or contributed data to each outcome is not reported in the registry record.

Missing-data handling is also not reported. In general, missing endpoint measurements can affect a response percentage if participants without complete evaluations are excluded, counted as nonresponders, or handled using another method. Those choices can lead to different interpretations. The registry does not indicate how incomplete response assessments, withdrawal, loss to follow-up or unavailable survival information were handled. The record’s Terminated status does not establish that data were missing or that follow-up was incomplete; the reasons and consequences of termination are not reported.

Without an analysis population, participant flow, missing-data method and multiplicity plan, the reproducibility and scope of any eventual estimates cannot be assessed from this record. These omissions should be distinguished from evidence that any particular method was or was not used outside what the registry reports.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: neutrophil count decreased (46.7%), white blood cell decreased (33.3%), febrile neutropenia (20.0%), hyperglycemia (20.0%), infusion related reaction (13.3%).

The safety summary separates participants by prior-treatment group. For serious adverse events, the record lists 15 participants at risk in each group and 11 affected participants in the Treatment Naive group and 9 in the Relapsed/Refractory group. For other adverse events, it lists 15 at risk in each group, with 15 affected in the Treatment Naive group and 14 in the Relapsed/Refractory group. The death counts are 7 and 6, respectively. These are descriptive counts; they do not establish why an event occurred or whether it was caused by treatment.

The listed serious adverse event terms include neutrophil count decreased at 46.7%, white blood cell decreased at 33.3%, febrile neutropenia at 20.0%, hyperglycemia at 20.0%, infusion related reaction at 13.3%, and lymphocyte count decreased at 13.3%. The registry does not provide further detail in this summary about event timing, severity by individual, recurrence, exposure duration or attribution to a particular drug. The percentages should therefore be read as registry-reported event summaries, not as comparative risks against another regimen.

The groups were not randomized and are defined by prior treatment status, so their safety counts are not a like-for-like control comparison. The record also does not report causes of death or establish whether deaths were treatment-related. These figures describe what the safety summary lists; they do not by themselves establish a causal relationship or comparative safety profile.

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

The registry record establishes that a Phase II, non-randomized study examined a sequential regimen of ofatumumab plus HDMP followed by ofatumumab plus alemtuzumab in participants with 17p deletion CLL. It identifies prior-treatment status as the basis for the two groups and defines induction overall response rate as the primary endpoint. It also specifies response criteria and an assessment schedule. These details clarify the clinical question the study was designed to address.

The record does not report the primary response rate, its 90% confidence interval, or the other listed outcome results. It therefore does not support a conclusion about the observed frequency of response, the precision of that frequency, or the study’s progression-free or overall survival outcomes. The absence of results in the registry record should not be interpreted as a zero response rate or as evidence that an outcome was unfavorable.

The design also limits what a group comparison could mean. Because participants were assigned according to prior treatment status rather than randomized, observed differences between the Treatment Naive and Relapsed/Refractory groups would be descriptive and potentially affected by differences between those populations. Both groups received the same described treatment sequence, so the design does not directly compare that sequence with an alternative treatment or control condition.

The safety summary reports event counts and serious adverse event terms, but does not establish the cause of events or the relationship of deaths to treatment. It also does not provide a randomized comparator for judging relative safety. The registry status is Terminated, while the reason for termination and its implications for follow-up are not reported. Taken together, the record documents a study question and design, along with selected safety information, but leaves the principal efficacy results and important analytic details unavailable. No treatment recommendation or causal judgment can be drawn from these registry entries alone.

14. Why This Trial Matters Statistically

This trial is statistically notable because its two groups reflect different treatment histories, not different assigned treatments. That distinction determines how any group-specific outcomes should be interpreted. A contrast between Treatment Naive and Relapsed/Refractory participants would not isolate the effect of a treatment choice, because prior treatment status was not randomized and may be associated with other participant or disease characteristics.

The primary endpoint is a percentage based on a multi-part clinical response definition. Its interpretation depends on the number of participants assessed, the number meeting response criteria and the way incomplete assessments are handled. Although the registry specifies a 90% confidence interval as the intended measure of uncertainty, it does not report the response estimate or interval. The key statistical questions of event frequency and precision therefore remain unanswered in the record.

The registry lists numerous secondary outcomes, including response, minimal residual disease, transplant, hyperglycemia and survival measures. Without reported results or a stated multiplicity strategy, it is not possible to judge the evidence across that outcome set or determine how the primary endpoint was distinguished from secondary analyses. The absence of a reported analysis population, missing-data approach and statistical plan further limits reproducibility.

The safety summary illustrates another interpretive issue: counts from groups defined by prior treatment status are not a controlled comparison. Event listings can describe what was recorded, but do not independently establish causation or comparative risk. The Terminated status also needs context that the registry does not provide. The reason for termination, any effect on follow-up, and the completeness of outcome collection are not reported. These features make the registry useful for understanding the planned question and the limits of inference, while leaving the trial’s efficacy conclusions unresolved.

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 primary limitation for interpretation is that the registry record does not report the primary endpoint result. No response percentage, response count, analysis denominator or 90% confidence interval is available. The endpoint definition and schedule cannot substitute for these outcome data. The record also does not report the results of the listed secondary outcomes, including 3-year progression-free and overall survival probabilities.

The study was non-randomized, and group assignment followed prior treatment status. Therefore, the groups cannot serve as randomized comparators. Differences in outcomes between them, if reported, could reflect their different histories or other factors rather than the treatment sequence. There is no alternative-treatment or untreated control group described in the registry record.

Enrollment was 30, but participant flow is not reported. The record does not state how many participants started the sequence, completed treatment, were assessed for response, or remained under follow-up for survival outcomes. It does not report an analysis population or explain how missing assessments and withdrawals were handled. The statistical analysis plan, sample-size justification and interim analysis procedures are not reported in the registry record.

The treatment descriptions are incomplete: the arm text stops during the ofatumumab dosing description for later cycles, and detailed dosing information for the subsequent ofatumumab-alemtuzumab part is not reported. Although the study status is Terminated, the reason and consequences are not given. Safety summaries provide selected counts and event terms but do not identify event causes, treatment attribution or death causes. These limitations restrict assessment of treatment exposure, outcome completeness, statistical precision, efficacy and safety comparisons.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Ofatumumab With High Dose Methylprednisone Followed by Ofatumumab and Alemtuzumab in 17p CLL — NCT01465334.
• Registry record last updated 2023-08-29; status last verified 2023-08.
• Results first posted 2019-06-26.
• 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

NCT01465334 is a Phase II, non-randomized, parallel-group study with no masking, listed as Terminated. The registry reports enrollment of 30, a start date of 2011-12 and a primary completion date of 2014-11. Participants were grouped by prior treatment status as Treatment Naive or Relapsed/Refractory, and both groups received the same described sequential therapy: ofatumumab plus high-dose methylprednisolone followed by ofatumumab plus alemtuzumab.

The primary endpoint was induction overall response rate, defined by International Workshop on Chronic Lymphocytic Leukemia criteria, with a 90% confidence interval specified. The record describes a response assessment schedule and lists secondary response, disease, safety and survival outcomes. It does not report primary or secondary outcome results, an analysis plan, the reason for termination, or the handling of missing data. Safety information includes group-level counts and selected serious adverse event terms, but does not establish causation or comparative risk.