Study to Evaluate the Efficacy and Safety of Treatment With Bendamustine in Combination With Ofatumumab in Previously Untreated Patients With Indolent B-Cell Non-Hodgkin's Lymphoma (NHL): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Evaluate the Efficacy and Safety of Treatment With Bendamustine in Combination With Ofatumumab in Previously Untreated Patients With Indolent B-Cell Non-Hodgkin's Lymphoma (NHL) (NCT01108341), a na phase 2 study. The primary outcome is Percentage of Participants With a Best Overall Response of Complete Response (CR) or Partial Response (PR), as Determined by the International Working Group (IWG) Criteria As Assessed by Investigators.

2. Clinical Question

The clinical question is a within-group response question, not a comparative treatment-effect question. The registry identifies overall response, defined as complete response plus partial response, as the primary objective. The endpoint is an investigator assessment under the International Working Group criteria, and its stated timeframe is up to Week 32.

The record gives the endpoint definition but not the observed percentage or its 95% confidence interval. It therefore does not report the numerical answer to the primary question. A response proportion, even when reported, describes the observed group and does not by itself establish what would have happened under another treatment or without treatment. With no separate control group, differences attributable to the combination cannot be separated from other influences on response.

3. Trial Design

This is a completed, open-label Phase 2, single-group study registered as NCT01108341. The registry lists an enrollment of 50 and identifies Cephalon as the sponsor. The study concerns treatment of previously untreated patients with indolent B-cell non-Hodgkin's lymphoma. Its listed start is 2010-05, and its primary completion is 2011-07.

Participants received bendamustine in combination with ofatumumab. The record describes 6 planned and 2 optional 28-day cycles. Bendamustine was administered intravenously at 90 mg/m^2 on study days 1 and 2; ofatumumab was administered intravenously at 300 mg on day 1 and 1000 mg on day 8. The available regimen description ends before its full schedule is stated, so additional regimen details are not reported in the registry record.

Allocation is listed as not applicable, masking as none, and the model as single group. Thus, the record describes neither random assignment to treatment groups nor a masked comparison. An open-label design means investigators and participants are not masked to treatment assignment. That matters when an endpoint depends on assessment, although the registry does not report procedures used to reduce assessment bias.

The primary outcome is the percentage of participants with a best overall response of complete response or partial response, assessed by investigators using International Working Group criteria up to Week 32. The described primary population is the safety population of participants who were treated. A secondary outcome concerns complete response. The registry lists two outcome measures in total, but does not report their numerical results in the available record. The planned enrollment is not the same as the number treated or the number contributing to each outcome; those outcome-specific denominators are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety population of participants who were treated

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 Percentage of Participants With a Best Overall Response of Complete Response (CR) or Partial Response (PR), as Determined by the International Working Group (IWG) Criteria As Assessed by Investigators, measured over up to Week 32.

The primary endpoint is the percentage of treated participants whose best overall response was complete response or partial response under the International Working Group criteria, as assessed by investigators up to Week 32. It combines two categories of tumor response into one overall response measure. The registry describes complete response as disappearance of all detectable clinical evidence of disease and disease-related symptoms, if present before therapy. Partial response requires at least a 50% decrease in the sum of the product of the diameters of up to 6 of the largest dominant nodes or nodal masses, with no increase in the size of other nodes, liver, or spleen, and no new disease sites.

A response proportion is used to describe how many participants in the assessed group met the endpoint definition. The accompanying 95% confidence interval, when available, conveys uncertainty around that proportion: a wider interval indicates less precision, while a narrower interval indicates greater precision. This general interpretation does not establish that the result applies to other populations or that treatment caused the observed responses.

The registry states the endpoint and its confidence-interval format but does not report the primary percentage, confidence limits, or analyzed denominator. The numerical response estimate and its precision are therefore not reported in the registry record. The secondary complete-response endpoint is listed, but its result is also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a response proportion describe?

A response proportion is a binary-outcome summary: each assessed participant either meets the endpoint definition or does not. Here, the endpoint groups complete response and partial response together. The proportion would describe the share of the analyzed participants who achieved either category. It is not a measure of time until response, duration of response, or change in symptoms unless those are separately defined and reported. Those additional outcomes are not reported in the registry record.

Interpretation depends on a clear denominator. The registry describes the primary population as the safety population of treated participants, but the number included in the response analysis is not reported. Enrollment is 50, while 49 participants are listed as at risk in the adverse-event summary. The record does not identify the endpoint-specific denominator, so neither count should be silently substituted for it.

How should a confidence interval be read?

A confidence interval communicates uncertainty about an estimate. In general, it gives a range of values compatible with the observed data under the assumptions of the interval method. It is not a guarantee that the true value lies within the reported range, and it does not show whether the result is clinically important. A confidence interval is most useful when read alongside the point estimate, endpoint definition, and analysis population.

The primary outcome lists a 95% confidence interval as its dispersion measure, but neither the response estimate nor its interval is reported in the registry record. The precision of the primary result therefore cannot be evaluated. The confidence level alone cannot be used to infer whether the result was close to a threshold or whether uncertainty was small or large.

What does the single-group design permit?

In a single-group study, participants receive the study treatment without a separate assigned comparator group. The observed response can be described for the treated group, but it cannot provide the same direct contrast as a randomized comparison. Without a contemporaneous control group, changes due to disease course, assessment, or other influences cannot be separated from changes associated with treatment. This is a general limitation of single-group evidence, not a claim about what occurred among participants in this study.

The record lists allocation as not applicable and masking as none. It therefore does not describe random assignment or masking. A lack of masking may matter for investigator-assessed outcomes, but the record does not report additional assessment safeguards or whether response assessments were independently reviewed.

What can be inferred from the planning illustrations?

The stated planning approach uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes effects to detect as stated fractions of the observed effect. Those are assumptions for planning illustrations, not a description of the actual single-group design. The record does not report a protocol-based sample-size justification, and it does not provide the observed response effect needed to interpret such illustrations. The planning values are not observed power and should not be read as evidence that the study had a particular probability of detecting an effect.

General sample-size planning asks how much information a design may need to detect a specified effect under chosen assumptions. Such a calculation depends on the assumed effect, variability, error rate, allocation, and analysis method. Changing those assumptions can change the planning result. A planning calculation is not a substitute for the observed estimate and its uncertainty, and it cannot fill in an outcome result absent from the registry record.

Why does over-dispersion matter?

For binary outcomes, simple models may assume that variation follows a specified probability structure. Over-dispersion, in general, means the data vary more than that model expects. If unaccounted for, uncertainty estimates can be too optimistic. Whether over-dispersion was assessed or addressed in this study is not reported in the registry record. No particular modeling approach or adjustment should be inferred from the endpoint definition alone.

The outcome is listed as a percentage of participants with an event, but the record does not state the calculation method for the confidence interval. It does not report an adjusted analysis, a model, or covariates. Consequently, the method used to obtain the interval and whether any adjustment affected the result are not reported in the registry record.

What is the role of statistical significance?

A p-value, when reported, summarizes how incompatible the observed data are with a specified null model under its assumptions. It does not measure the probability that a treatment works, the size of an effect, or the clinical importance of a result. The registry lists no analysis entries and reports no p-value for the primary outcome. A significance conclusion cannot be drawn from the endpoint description or the planning assumptions.

For a single-group response proportion, the question may be framed against a benchmark only if that benchmark and analysis are specified. No such benchmark is reported in the registry record. The stated two-sided significance level belongs to the planning illustration assumptions and does not establish that the trial tested a particular hypothesis.

How should event listings be interpreted?

Safety counts and percentages describe events recorded in the study population. They do not by themselves establish causality. Serious adverse event terms are listed with percentages, but the registry does not report the event-level participant histories, attribution judgments, duration, or outcomes for those terms. Such details are not reported in the registry record. These limitations apply to interpretation of the listed events, regardless of whether an event is common or uncommon.

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("Bendamustine and Ofatumumab")
n      <- c(49)
events <- c(44)
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  Bendamustine and Ofatumumab  49  44  89.8  77.8  96.6  78.2  95.6  78.2  95.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures: the primary overall-response endpoint and a secondary complete-response endpoint. It does not report a statistical plan for controlling multiplicity, such as an order for testing endpoints or an adjustment to account for multiple comparisons. Whether such procedures were specified elsewhere is not reported in the registry record. Results for the secondary endpoint are also not reported in the registry record.

The record describes the primary analysis population as treated participants in the safety population. It does not report a separate intention-to-treat population or other analysis populations. Although the safety summary lists 49 participants at risk, the primary endpoint denominator is not reported. The enrollment figure of 50 does not establish that all enrolled participants were treated or assessed for response.

Missing outcome data can affect a response proportion if participants without an assessment are excluded or classified in a particular way. The registry does not report how missing response assessments were handled, whether participants were excluded from the endpoint analysis, or whether sensitivity analyses were performed. These details are not reported in the registry record. The reader therefore cannot determine from this record whether missingness could have influenced the primary estimate.

The registry lists no analysis entries. It does not report interim analyses, statistical adjustment, or a detailed analysis plan. Their presence or absence in other study documents is not reported in the registry record. Without the analysis denominator, missing-data approach, and numerical endpoint result, the response analysis cannot be fully reconstructed from the registry information.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: febrile neutropenia (4.1%), infusion related reaction (4.1%), pyrexia (4.1%), diplopia (2.0%), ascites (2.0%).

The safety summary lists 49 participants at risk for serious adverse events, of whom 14 were affected. It also lists 49 participants at risk for other adverse events and 49 affected. These are counts in the registry record; they should be read in their stated categories, not combined into a new total. The record does not provide a comparison group for interpreting these counts.

The listed serious adverse event terms and percentages are febrile neutropenia, 4.1%; infusion related reaction, 4.1%; pyrexia, 4.1%; diplopia, 2.0%; ascites, 2.0%; and colitis, 2.0%. These entries describe the registry's reported terms and percentages. They do not establish that an event was caused by treatment, and the record does not provide further detail about event timing, severity beyond the serious-event classification, or clinical course.

Deaths are not reported in the registry record. This should not be read as evidence that no deaths occurred. Likewise, the absence of additional detail in the record does not establish that no other safety events were observed. The listed counts and terms are descriptive and are not a substitute for a comparative safety analysis.

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

The study addresses whether treated participants with previously untreated indolent B-cell non-Hodgkin's lymphoma had a best overall response of complete response or partial response by investigator assessment. The registry defines the response categories and specifies assessment up to Week 32. It also reports that the design was open-label and single-group, with planned enrollment of 50.

The main numerical result needed to answer the primary question—the observed response percentage and its 95% confidence interval—is not reported in the registry record. The secondary complete-response result is not reported either. As a result, the posted record does not show the proportion of participants who responded or how precisely that proportion was estimated. No conclusion about the magnitude of the response observed in the study can be drawn from the endpoint definition alone.

Even if a response percentage were available, a single-group result would describe the treated participants rather than provide a randomized comparison with another treatment or a control condition. It would not, by itself, distinguish the contribution of the combination from other influences. The record contains no like-for-like control group, so it does not support a comparative estimate.

The safety summary gives counts for participants affected and lists selected serious adverse event terms with percentages. These entries are useful as descriptive information about the reported safety record, but they do not establish causation or comparative risk. Deaths and further details needed to interpret the event courses are not reported in the registry record.

The record therefore documents the study question, treatment combination, outcome definition, and selected safety information. It does not supply the primary response result or enough analysis detail to reconstruct it. Its statistical meaning is consequently limited: design and endpoint can be described, but response magnitude, precision, and comparative effect cannot be determined from the registry record.

14. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and numerical results must be distinguished. The registry carefully states what counted as complete response and partial response, identifies the treated safety population, and gives a time window for assessment. Yet without the observed response percentage, confidence interval, and analyzed denominator, the central efficacy outcome cannot be quantitatively interpreted. A detailed endpoint definition is necessary for reproducibility, but it is not itself evidence about the observed result.

It also shows why trial design is central to statistical interpretation. An open-label, single-group study can describe outcomes among treated participants, but it does not provide the direct treatment contrast that random allocation to a comparator can support. The absence of a control group is not repaired by a large or small response estimate; it changes the kind of conclusion the design can support.

The safety information demonstrates a related distinction between event counts and causal conclusions. The record lists participants affected and selected serious adverse event terms, but those figures do not establish whether treatment caused an event. A safety interpretation depends on context, including comparison, definitions, follow-up, and event-level details, much of which is not reported in the registry record.

Finally, planning assumptions should not be mistaken for study findings. The registry's stated sample-size illustration assumptions refer to a two-arm planning framework, while this trial is described as single group. Such assumptions can support hypothetical planning questions, but they are not the actual study design, observed power, or a substitute for its missing outcome result. Reading design, planning, and results as separate kinds of evidence is essential to keeping conclusions appropriately bounded.

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 consequential limitation of the registry record for statistical interpretation is that it does not report the numerical primary outcome. The response percentage, its 95% confidence interval, and the endpoint-specific denominator are not reported in the registry record. The secondary complete-response result is also not reported. These omissions prevent assessment of the primary result's size and precision.

The single-group, open-label design has no separate comparator and no masking. This prevents a like-for-like treatment contrast in the registry record and may be relevant to an investigator-assessed endpoint. The record does not describe independent review or other procedures for limiting assessment bias.

Enrollment is 50, whereas the adverse-event summary identifies 49 participants at risk. The record does not explain this distinction or state how many participants were assessed for response. It also does not report handling of missing response data, exclusions, sensitivity analyses, or a complete analysis plan. The implications of missing or unevaluable participants therefore cannot be assessed.

The registry lists two outcomes but does not report multiplicity procedures, interim analyses, or a protocol-based sample-size justification. Whether any of these were specified outside the registry record is not reported. The planning assumptions describe an equal-allocation, two-arm illustration, which is not the listed single-group design; the assumed planning results do not establish the actual design or observed power.

For safety, event counts and selected serious event terms are available, but deaths, causality assessments, event timing, and further event details are not reported in the registry record. No comparator safety data are listed. These limitations restrict both efficacy and safety interpretation to a description of the information that the registry reports.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study to Evaluate the Efficacy and Safety of Treatment With Bendamustine in Combination With Ofatumumab in Previously Untreated Patients With Indolent B-Cell Non-Hodgkin's Lymphoma (NHL) — NCT01108341.
• Registry record last updated 2012-08-28; status last verified 2012-07.
• Results first posted 2012-08-28.
• 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

NCT01108341 is a completed, open-label, single-group Phase 2 study of bendamustine with ofatumumab in previously untreated patients with indolent B-cell non-Hodgkin's lymphoma. Enrollment is listed as 50. The primary endpoint is the percentage of treated participants with a best overall response of complete response or partial response by investigator assessment under International Working Group criteria, up to Week 32.

The registry describes the endpoint and a 95% confidence interval but does not report the primary response estimate, interval, or analyzed denominator. It lists a secondary complete-response outcome without a numerical result. Safety information identifies 49 participants at risk for serious adverse events, with 14 affected, and lists selected serious-event terms and percentages. Deaths are not reported in the registry record. The single-group design does not provide a randomized comparator.