Ofatumumab for Minimal Residual Disease (MRD) and Maintenance Therapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ofatumumab for Minimal Residual Disease (MRD) and Maintenance Therapy (NCT01258933), a na phase 2 study. The primary outcome is Number of Patients With Objective Response.

2. Clinical Question

The study asks whether ofatumumab can control chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) remaining after chemotherapy or chemoimmunotherapy. It also aims to study the drug’s safety. The registry record describes a single group receiving ofatumumab, without a randomized comparator.

The registry defines response using 2008 International Working Group for CLL criteria. It describes conversions among complete remission, partial remission, nodular partial remission, and minimal residual disease-negative status. Response evaluation includes physical examination, blood counts, imaging, and bone marrow assessment, including residual disease assessment by 4-color flow cytometry.

The listed secondary outcomes are time-to-treatment failure and progression-free survival. The registry record does not report results for those outcomes. It also does not report the number of participants with an objective response, so the central question cannot be answered from the posted results.

3. Trial Design

This is a Phase 2, single-group study sponsored by M.D. Anderson Cancer Center. The registry record lists enrollment of 4 and no allocation to different treatment groups. Masking is recorded as none. These features make the study a non-randomized treatment cohort rather than a like-for-like comparison of ofatumumab with another treatment or with no treatment.

The intervention is ofatumumab. The regimen starts with a 300 mg dose, followed by 1,000 mg weekly for 7 doses. Maintenance is described as 1,000 mg every 2 months beginning on week 12, for a total of 2 years of treatment or until disease progression. Follow-up is described as the period after maintenance is completed. The registry does not report how many participants received each part of this schedule or how long each participant remained on treatment.

The primary outcome is the number of participants with objective response at week 12, before the 9th dose and before the first bimonthly dose. The registry also lists time-to-treatment failure and progression-free survival as secondary outcomes. Their definitions, analysis methods, and results are not reported in the registry record.

The study start is listed as 2011-07-06, and the primary completion date is listed as 2024-10-18. The study status is terminated. The registry record does not explain the reason for termination or describe how termination affected enrollment, treatment, follow-up, or analysis. The small enrollment and absence of a control group are important when interpreting any observed counts: results can describe this group, but do not provide a randomized estimate of a treatment difference.

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 Number of Patients With Objective Response, measured over Week 12.

The primary endpoint is the number of participants with an objective response at week 12. It is a count endpoint: it records how many participants meet the stated response criteria at the specified assessment time. The registry record does not report that count or the number assessed for response.

The response definition allows several forms of improvement in disease status. These include conversion from complete remission to minimal residual disease-negative status, from partial remission to nodular partial remission or complete remission, and from nodular partial remission to complete remission. Assessment is described as following 2008 International Working Group for CLL criteria. The listed evaluation methods include physical examination, CBC, CT of the chest, abdomen, and pelvis, and bone marrow aspirate and biopsy, with residual disease assessed by 4-color flow cytometry.

A defined time point and response rule make an endpoint interpretable: they specify when response is assessed and which clinical and laboratory findings count. Response at week 12 is an assessment at that point in the treatment schedule, not a measure of how long a response lasts. The registry separately lists time-to-treatment failure and progression-free survival as secondary outcomes, which address time-related outcomes, but does not report their results.

Because the response count is not reported, the endpoint’s observed frequency and its precision cannot be described. The available record identifies what was intended to be measured, but not what the assessment found.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation starts with identifying the type of outcome, the group being described, and the analysis that produced the result. The primary outcome in this study is a count of participants with objective response at week 12. The registry record specifies the outcome definition and assessment time, but does not report a response count, an estimate of uncertainty, or an analysis result. Without those items, a numerical description of the primary outcome is not possible.

What does a count endpoint tell us?

A count endpoint records how many people meet a defined criterion. It is directly interpretable as a tally, provided the number assessed and the outcome definition are clear. A count alone does not describe how precisely the result estimates an underlying response frequency. Statistical uncertainty is often conveyed with a confidence interval: in general, a confidence interval gives a range of values compatible with the data under the method used. The registry record does not report a confidence interval for the primary endpoint.

The denominator matters when interpreting a count. Enrollment is listed as 4, but the number assessed at week 12 is not reported in the registry record. Enrollment and the number assessed are not necessarily interchangeable: the registry record does not state whether every enrolled participant reached the assessment or how missing assessments were handled. Therefore, the response proportion cannot be inferred from enrollment, and no response proportion is reported.

Why does the study design matter?

A single-group study describes outcomes among people who received the intervention. Because this trial has no separate control group, it does not directly estimate how outcomes would differ under another treatment or without ofatumumab. A randomized comparison is designed to support a treatment contrast by assigning participants to groups; this study is not described as randomized. The registry lists allocation as NA and masking as none. These are design features, not evidence for or against an outcome.

Comparisons between a single-group result and outcomes from other populations would require careful consideration of differences in eligibility, prior treatment, assessment, and follow-up. Such comparisons are not reported in the registry record. The study’s stated aim is to examine disease control and safety after prior chemotherapy or chemoimmunotherapy, but the record does not report enough outcome information to assess disease control.

What do time-to-event outcomes add?

Time-to-treatment failure and progression-free survival are listed as secondary outcomes. In general, time-to-event methods account for the time until a defined event and can incorporate participants whose observation ends before the event is recorded, using censoring methods. How those outcomes were defined, which events counted, how censoring was handled, and what estimates were obtained are not reported in the registry record. No time-to-event estimate should therefore be inferred from the outcome names alone.

How should planning illustrations be read?

General sample-size planning uses assumptions about the effect to be detected, the significance level, the allocation between groups, and the statistical approximation. The registry record describes planning illustrations based on a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is expressed as a stated fraction of an observed effect. For time-to-event illustrations, the stated quantity is a total number of events; other illustrations refer to participants per arm.

Those assumptions are planning illustrations, not the design of this single-group trial and not evidence about what happened among participants. They are not observed power. A sample-size calculation is a prospective planning tool, whereas observed outcomes and their uncertainty require actual analysis results. The registry record does not report the trial’s own sample-size justification. In addition, the primary response result is not reported, so the observed effect underlying any illustration cannot be evaluated from the posted results.

What is unavailable about the statistical plan?

The registry record reports 0 analyses. It does not report the statistical methods used for the primary endpoint, the analysis population, handling of missing outcome data, or whether any adjustment was made for other factors. It also does not report an interim-analysis plan or the reason for termination. These are not details that can be recovered from the endpoint definition or from the adverse-event counts. Without them, readers cannot determine whether the posted entries reflect a complete analysis or how the planned analysis related to any analysis conducted.

In general, statistical methods translate observed data into estimates and quantify uncertainty under stated assumptions. Their interpretation depends on the data included, outcome definitions, follow-up, and analysis choices. For this trial, the registry describes the endpoint and design but does not provide the primary result or the analysis details needed to evaluate those elements. The appropriate reading is descriptive: the record gives selected study characteristics and safety tallies, while leaving efficacy estimates and their precision unreported.

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("Ofatumumab")
n      <- c(4)
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  Ofatumumab  4  0  0.0  0.0  60.2  0.0  49.0  0.5  52.2

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and two secondary outcomes: time-to-treatment failure and progression-free survival. It does not report a multiplicity strategy, such as whether or how inference across several outcomes was to be controlled. In general, testing several outcomes can increase the chance of a false-positive finding if results are interpreted without accounting for the number of tests. No multiplicity-adjusted or unadjusted outcome analyses are reported in the registry record, so this issue cannot be assessed from posted estimates.

The registry reports 0 analyses and does not identify an analysis population for the primary or secondary outcomes. It does not state whether analyses were intended to include all enrolled participants, only those who received treatment, or a different group. The number evaluated at week 12 is not reported, and no primary response count is given. A missing-data method, reasons for missing assessments, and the handling of incomplete follow-up are also not reported in the registry record.

These omissions matter because the denominator and analysis population affect how a count is interpreted. In general, an analysis limited to participants with an observed assessment may differ from one that includes all enrolled participants under a specified missing-data approach. No such approach can be attributed to this study based on the registry record.

The registry record does not report an interim-analysis plan, stopping rules, or the statistical plan associated with termination. It also does not explain whether any planned analysis was completed. These details should be treated as unknown, rather than inferred from the status or listed completion date.

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 non-serious adverse event terms

The registry’s adverse-event entries list 0 of 4 participants at risk as affected by a serious adverse event. For other adverse events, 4 of 4 participants at risk are listed as affected. The record also lists 1 death. These are participant counts, not rates adjusted for time at risk, and the registry does not report the duration of observation used for these entries.

No serious adverse-event terms are listed. The types of other adverse events, their severity, timing, duration, and relationship to treatment are not reported in the registry record. The record also does not explain whether the death was related to an adverse event or to the study treatment. The death count should therefore be read separately from the serious-adverse-event count; the available entries do not establish a relationship between them.

These safety counts describe the small enrolled group and should not be read as a complete characterization of possible harms. In general, small groups provide limited information about uncommon events, and the number at risk alone does not convey how long participants were observed. The registry does not report further safety analyses or the criteria used to classify events.

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

The registry record establishes that this was a Phase 2, single-group study of ofatumumab for CLL or SLL with residual disease after chemotherapy or chemoimmunotherapy. It describes the treatment schedule, a week 12 objective-response endpoint, and selected adverse-event counts. Those details identify the question the study was intended to address and the basic context for the recorded results.

The record does not report the number of participants with objective response, a confidence interval, or results for time-to-treatment failure or progression-free survival. It therefore does not show how many participants met the response definition or how precisely any response frequency was estimated. The absence of reported results is not evidence that there were no responses or that outcomes were unfavorable; the outcome findings are simply not reported in the registry record.

The adverse-event entries report 0 serious adverse events among 4 participants at risk, other adverse events in 4 of 4, and 1 death. They do not give enough detail to identify the events or assess their timing, severity, or relationship to treatment. The counts should be understood as registry entries for this group, not as a comprehensive estimate of risk across a broader population.

Because there is no control group, the study cannot provide a randomized comparison of outcomes with and without ofatumumab. Even a reported response count would describe the observed group rather than establish what would have happened to comparable patients under another approach. The small enrollment further limits the precision and breadth of conclusions that could be drawn from this cohort.

The study status is terminated. The reason and implications are not reported in the registry record. Thus, the record supports a description of the study design and selected safety counts, but not a conclusion about the primary efficacy outcome, comparative effectiveness, or the causes of any observed events.

14. Why This Trial Matters Statistically

This trial illustrates why a clearly defined endpoint and an available result are both needed for statistical interpretation. The registry specifies a week 12 response assessment and describes the response categories and evaluation methods. Yet without the observed response count or an estimate of uncertainty, readers cannot quantify the primary outcome. A protocol-level definition clarifies what would count as response; it does not reveal how many participants met that definition.

The single-group design also illustrates the distinction between describing an outcome and estimating a treatment contrast. An observed result in people receiving ofatumumab could describe that cohort, but the absence of a comparator means the record cannot directly estimate a difference attributable to treatment. This distinction is especially important when the target population has already received chemotherapy or chemoimmunotherapy and the study addresses residual disease.

Enrollment of 4 makes the denominators and participant-level outcomes central to interpretation. Small cohorts can be useful for describing feasibility or generating further questions, but their results are limited in precision and may not represent the range of outcomes in a wider population. The registry record does not give enough outcome information to assess even a response count in this cohort.

The safety entries provide another statistical lesson: counts must be read with their definitions and context. The serious-event count, other-event count, and death count are distinct entries, and the record does not provide event terms or relationships among them. A count without detail cannot characterize the nature or timing of safety events.

Finally, the record lists planning assumptions separately from the trial’s design and reports no analyses. This distinction helps prevent planning calculations from being mistaken for observed evidence. Statistical transparency depends not only on methods and assumptions, but also on reported outcomes, denominators, and uncertainty. Several of those elements are not reported in the registry record.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main limitation of the available record is that the primary endpoint result is not reported. The number of participants with objective response at week 12, the number assessed, and any estimate of uncertainty are absent. Results for the listed secondary outcomes, time-to-treatment failure and progression-free survival, are also not reported.

The study enrolled 4 participants and used a single-group design, with no listed randomized comparator. The small cohort limits the amount of outcome information available, while the lack of a control group prevents a direct treatment comparison. The registry status is terminated, but the reason for termination and any effect on enrollment, treatment exposure, follow-up, or analysis are not reported in the registry record.

Several details needed to interpret the outcomes are also unavailable. The record does not report the analysis population, the number assessed for the primary endpoint, missing-data handling, follow-up completeness, or the statistical methods used for any outcome. It does not report whether the intended analysis was completed, or describe interim analyses or the statistical plan.

Safety reporting is limited to participant counts. Serious adverse-event terms are not listed, and the record does not describe the types or timing of other adverse events, their severity, treatment relationship, or the relationship of the recorded death to any event or treatment. The available safety counts therefore do not provide a detailed safety profile.

These limitations concern what is reported in the registry record. They do not establish that unreported analyses or details were never collected or conducted; their status is not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Ofatumumab for Minimal Residual Disease (MRD) and Maintenance Therapy — NCT01258933.
• Registry record last updated 2025-10-01; status last verified 2025-09.
• Results first posted 2025-10-01.
• 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 record describes a Phase 2, single-group study of ofatumumab for residual CLL or SLL after chemotherapy or chemoimmunotherapy. Enrollment was 4. The study status is terminated, and the listed primary completion date is 2024-10-18.

The primary endpoint is the number of participants with objective response at week 12, assessed according to 2008 International Working Group for CLL criteria. Time-to-treatment failure and progression-free survival are listed as secondary outcomes. The primary and secondary outcome results are not reported in the registry record; the record lists 0 analyses.

For safety, the record lists 0 of 4 participants affected by serious adverse events, 4 of 4 affected by other adverse events, and 1 death. Serious-event terms and further details about event types, timing, and relationships are not reported in the registry record.