A Study of Bendamustine in the Treatment of Chinese Participants With Indolent Non-Hodgkin Lymphoma Refractory to Rituximab Treatment: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Bendamustine in the Treatment of Chinese Participants With Indolent Non-Hodgkin Lymphoma Refractory to Rituximab Treatment (NCT01596621), a na phase 3 study. The primary outcome is Overall Response Rate (ORR) (Assessed by Independent Review Committee [IRC]).

2. Clinical Question

The study’s primary objective was to estimate overall response rate in a population whose disease had progressed after rituximab treatment. This is a descriptive question about the proportion of participants classified as having a complete or partial response during the study. The registry describes the response definitions and the analysis population, but does not report the ORR estimate, its numerator, or a confidence interval. The response result is therefore not reported in the registry record.

Because the design has no concurrent control group, it does not directly compare bendamustine with another treatment or with a control condition. The study can describe responses observed among treated participants, but the design alone cannot separate a treatment effect from other influences on response or its measurement. That distinction matters when interpreting an uncontrolled response proportion: it is an observed outcome in the study population, not a comparative estimate.

The record lists additional outcomes, including duration of response and progression-free survival assessed by the Independent Review Committee, along with bendamustine pharmacokinetic measures. Their results are not reported in the registry record. The primary question remains focused on response, while the listed secondary outcomes address how long responses or disease control lasted and how drug concentrations changed over time.

3. Trial Design

This was a completed Phase 3, open-label, single-group study sponsored by Teva Branded Pharmaceutical Products R&D, Inc. The registry lists Non-Hodgkin Lymphoma as the condition and Chinese patients with indolent non-Hodgkin lymphoma refractory to rituximab treatment as the study population. Enrollment was 102. The study started on 2012-08-06 and its primary completion date was 2015-06-18.

All participants were assigned to the bendamustine group; the record describes allocation as not applicable because the design was single-group. Masking was none. Thus, the design does not include a randomized or masked comparison. The absence of a comparator means that response and safety findings describe outcomes among participants receiving the study drug, without a concurrent group to provide a direct contrast.

The regimen was bendamustine hydrochloride at 120 milligrams per square meter, administered intravenously as a 60-minute infusion, and not more than 120 minutes, on Days 1 and 2 of each 21-day treatment cycle. The plan specified 6 treatment cycles, with up to 8 total cycles. The registry record does not describe additional treatment-delivery details beyond this regimen.

The primary outcome was overall response rate assessed by an Independent Review Committee. Its definition included complete and partial response under modified International Workshop Response Criteria. The primary analysis set included enrolled participants who received any amount of study drug. The registry record lists duration of response and progression-free survival, also assessed by the Independent Review Committee, as secondary outcomes, as well as pharmacokinetic outcomes for bendamustine.

The trial status is completed, but completion status is not itself evidence of a particular response or safety outcome. The primary response result and results for the listed secondary outcomes are not reported in the registry record. The record also does not report a statistical analysis plan, the rationale for the enrollment target, or details of monitoring during the study.

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: The primary analysis set (PAS) included all enrolled participants who were treated with any amount of study drug.

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 primary analysis set (PAS) included all enrolled participants who were treated with any amount of study drug.

6. Primary Endpoint

The registry lists the primary outcome as Overall Response Rate (ORR) (Assessed by Independent Review Committee [IRC]), measured over From the date of the first administration of bendamustine to the first documentation of disease progression/relapse, new anticancer therapy, or death (regardless of cause), whichever occurred first (up to 2.5 Years).

The primary endpoint, overall response rate, is the percentage of participants whose best response during the study was complete response or partial response. In general, an endpoint like this reduces a range of clinical observations to a binary classification: each participant either meets the response definition or does not. The resulting proportion describes how often the defined response occurred in the analyzed population.

The registry defines complete response as disappearance of all evidence of disease, including specified findings for nodal masses, spleen and liver, and bone marrow. Partial response requires regression of measurable disease and no new sites. The description includes a reduction of at least 50% in the sum of the product of diameters for up to 6 largest dominant masses, with no increase in other nodes; it also specifies the corresponding decrease for spleen and liver nodules without an increase in spleen or liver size. These criteria make the endpoint more explicit than a general impression of improvement.

Response rate is used to describe the proportion meeting prespecified response criteria. In an uncontrolled study it is a useful descriptive outcome, but it does not by itself establish what would have happened under another treatment or without the study treatment. Independent Review Committee assessment indicates that the endpoint was intended to be assessed by a committee separate from the treating investigator; the record does not provide further detail about its procedures.

The timeframe is described as from the first administration of bendamustine to the first documentation of disease progression or relapse, new anticancer therapy, or death, whichever occurred first, up to 2.5 Years. The response estimate itself is not reported in the registry record, so the observed percentage and its precision cannot be assessed from the recorded information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a binary percentage endpoint: overall response rate. In general, a binary endpoint classifies each participant according to whether a defined event or state occurred. For this study, the qualifying state was a best response of complete response or partial response under modified International Workshop Response Criteria. The percentage is intended to summarize the share of the analysis population meeting that definition. The record does not report the observed percentage or the underlying response count.

What does the response definition contribute?

Operational definitions help make outcome classification more reproducible. The record gives disease findings that distinguish complete response from partial response, including disappearance of disease evidence for complete response and regression of measurable disease without new sites for partial response. For partial response, the description specifies at least 50% decrease in the sum of the product of diameters for up to 6 largest dominant masses, alongside restrictions on increases in other nodes and specified spleen and liver findings. These criteria define what qualifies; they do not tell the reader how many participants qualified.

The endpoint was assessed by an Independent Review Committee. In general, independent review can separate endpoint assessment from the treating team’s direct role in care, but the registry record does not state the committee’s charter, blinding procedures, adjudication rules, or handling of disagreement. The study itself was open-label, so masking was absent at the trial level. The record does not establish whether any endpoint-specific review process used masking.

What does an interval add to a percentage?

A point estimate gives a single summary of the observed data. A confidence interval gives an indication of statistical precision by describing a range of values compatible with the data under a specified method and its assumptions. A narrow interval generally indicates greater precision than a wide interval. An interval does not remove design limitations, correct bias automatically, or turn an uncontrolled estimate into a treatment comparison. No primary endpoint confidence interval is reported in the registry record, and the response estimate itself is also not reported.

For a binary outcome, uncertainty depends on the observed response information and the method used to calculate the interval. The registry record does not report the method used for an interval or whether an interval was calculated. It would therefore be inappropriate to infer an interval or reconstruct one from the enrollment count alone. In particular, the number enrolled does not reveal the number who met the response definition.

How does the design affect inference?

This is a single-group study with no concurrent comparator. General statistical interpretation distinguishes a descriptive estimate within a group from a comparative effect between groups. A single-group response proportion can describe the observed frequency of response in the analyzed participants. It does not directly provide a contrast against another intervention, and it cannot control by design for differences in patient characteristics, changes over time, or other influences on outcome. Those constraints remain even if an estimate is precise.

Open-label conduct means masking was not used, according to the registry. For outcomes involving clinical classification, knowledge of treatment assignment can be relevant to assessment and care, although the presence and direction of any such influence cannot be inferred from the record. Independent Review Committee assessment is a feature of the endpoint description, but the exact safeguards and procedures are not reported.

What can safety counts tell readers?

Adverse-event counts describe how many participants in the recorded group were affected, relative to the listed number at risk. The record gives separate counts for serious adverse events and other adverse events. These categories should be read as distinct registry summaries rather than combined into a new total. Counts and percentages describe what was recorded during the study; without a control group, they do not estimate a comparative safety difference. They also do not establish that the study drug caused an event.

In general, adverse-event interpretation depends on definitions, collection procedures, duration of observation, and rules for coding and attribution. Those details are not reported in the registry record. Selected event-term percentages describe the listed terms and should not be read as a complete account of every safety outcome unless the record says they are exhaustive; it does not say that they are exhaustive.

What are planning illustrations?

The record describes sample-size assumptions for planning illustrations: two-sided significance level 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect stated as a fraction of the observed effect. For time-to-event planning, the description refers to total events; other planning illustrations are described as participants per arm. These are planning assumptions, not observed trial results. They are not a report of the original study’s design rationale, and the registry record does not report that rationale.

In general, a sample-size calculation estimates how much information a future design might need under stated assumptions. Its output depends on the assumptions, including the target effect and analysis approach. Such an illustration is not observed power and does not show that the completed study had a particular probability of detecting an effect. The registry record does not report a sample-size justification or the study’s own statistical design calculations.

No inferential analysis result is reported for the primary endpoint in the registry record. The record’s description of the endpoint and design permits a reader to understand what was intended to be measured, but not to quantify the observed response or its statistical uncertainty.

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")
n      <- c(102)
events <- c(74)
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  102  74  72.5  62.8  80.9  63.2  80.3  63.2  80.3

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary endpoint and multiple secondary outcomes. The secondary outcomes include duration of response and progression-free survival assessed by the Independent Review Committee, as well as maximum observed plasma concentration, time to reach that concentration, several area-under-the-curve measures, an elimination rate constant, and the percentage of area under the curve based on extrapolation. The results for these outcomes are not reported in the registry record.

When a study examines multiple outcomes or multiple statistical comparisons, the chance of at least one apparently notable result can increase. General methods for addressing multiplicity include identifying a primary outcome in advance, controlling error across a family of tests, or treating secondary analyses as exploratory. The registry identifies ORR as the primary objective, but the statistical plan for multiplicity, including any hierarchy or adjustment, is not reported in the registry record. No claim about whether an adjustment was used is warranted.

The primary analysis set is described as all enrolled participants who were treated with any amount of study drug. This defines the intended analysis population, but the registry record does not report the number included in the primary endpoint analysis, the response count, or how participants without an evaluable response were handled. It also does not report the missing-data rules, exclusions, or sensitivity analyses. Those details matter because missing outcome assessments can affect a proportion if the handling of unobserved responses is consequential.

The record reports enrollment of 102, but enrollment does not establish how many participants contributed to the primary analysis. It also does not establish whether every participant had a response assessment. The timing and frequency of assessment are not reported in the registry record. Accordingly, neither the extent nor the impact of missing primary outcome data can be assessed from this record.

General statistical practice distinguishes a prespecified analysis plan from analyses chosen after seeing outcomes, because the latter can increase the risk of selective emphasis. The registry record does not report enough detail to assess the statistical plan, interim analyses, or analysis choices. No conclusion about those procedures should be inferred from the study’s completed status or the outcome listings.

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: pyrexia (4.9%), pneumonia (4.9%), lung infection (3.9%), respiratory failure (3.9%), thrombocytopenia (2.9%).

The registry lists 102 participants at risk for serious adverse events in the bendamustine group, with 30 affected. It lists 102 at risk for other adverse events, with 99 affected. These categories are reported separately and should not be added together: the record does not explain overlap between them, and a combined count would not be justified.

The selected serious adverse-event terms and percentages are Pyrexia, 4.9%; Pneumonia, 4.9%; Lung infection, 3.9%; Respiratory failure, 3.9%; Thrombocytopenia, 2.9%; and Herpes zoster, 2.9%. These entries indicate the event terms and percentages recorded in the registry. They do not provide a full safety profile or a comparison with another treatment group.

In general, an adverse event is an event recorded during a study, and its presence alone does not establish that treatment caused it. Interpretation also depends on event definitions, collection methods, observation time, and attribution rules. Those details are not reported in the registry record. With no concurrent comparator, the counts describe events in the treated group rather than a difference in risk between treatments.

The record does not report death counts for the group. It also does not provide enough detail to infer how many events were experienced by each affected participant, whether events overlapped across terms, or how severity and relatedness were assessed. The listed counts and percentages should therefore be read as descriptive registry data, not as proof of causation or a comparative safety conclusion.

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

The study record describes an investigation of bendamustine in Chinese participants with indolent non-Hodgkin lymphoma refractory to rituximab treatment. It specifies an open-label, single-group design, the intravenous regimen, and a primary endpoint based on complete or partial response. These details define the question the study was intended to address and the outcomes it planned to assess.

The record does not report the primary ORR estimate. Consequently, it does not show what percentage of participants achieved a complete or partial response, how many met either response category, or how precise an estimate would be. The listed endpoint definition cannot be mistaken for a result. Nor does the completed status indicate whether the endpoint was met.

Even if a response percentage were available, the single-group design would support a descriptive interpretation of outcomes in the treated participants, not a direct comparison with another treatment. A response proportion alone cannot establish what would have occurred under a different treatment or without treatment. That is a general limitation of an uncontrolled design and does not imply a particular direction or size of effect.

The record’s safety entries describe serious adverse events and other adverse events in the bendamustine group. They do not establish causation, and without a comparison group they cannot quantify a difference in safety relative to another approach. The selected serious event terms are informative as recorded events, but they do not replace a complete assessment of the safety experience.

Secondary outcome names show that the study also addressed response duration, progression-free survival, and pharmacokinetics. Their results are not reported in the registry record. The record likewise does not report the primary endpoint’s confidence interval, missing-data handling, or statistical analysis details. The defensible interpretation is therefore limited to the study’s stated design, endpoint definitions, and recorded safety counts; efficacy magnitude and precision remain unreported.

14. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a clear endpoint definition and an absent endpoint result. The registry specifies ORR as the primary objective, defines complete and partial response, names the assessment committee, and describes the analysis population. Those details tell readers what the study intended to measure. They do not provide the observed estimate. Recognizing this gap prevents the study’s objective from being confused with evidence of an outcome.

The single-group design also illustrates why a response percentage and a comparative treatment effect are not interchangeable. A proportion can describe the experience of participants in a treated group, while a treatment comparison requires a suitable reference group and an analysis that supports the intended contrast. The registry lists no concurrent comparator. Even a precise within-group estimate would not resolve the absence of a control condition.

The record further separates efficacy reporting from safety reporting. It gives counts for serious and other adverse events and selected serious-event percentages, while the primary response result and listed secondary outcome results are not reported. Statistical review should preserve that distinction: available safety counts should not be used to imply an efficacy result, and event counts should not be interpreted as causal or comparative evidence without supporting design and analysis information.

Finally, the planning assumptions described in the record are not the same as a documented original sample-size rationale or an observed analysis. Planning illustrations based on an assumed effect can help frame design choices in general, but they cannot substitute for reported trial estimates, uncertainty intervals, or a transparent analysis plan. This study therefore highlights the importance of outcome reporting and of matching statistical claims to the design and evidence actually recorded.

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.

Several trial-specific limits follow directly from the registry record. The design is single-group, open-label, and has no concurrent comparator. As a result, the record cannot support a direct treatment contrast. The primary result is not reported, so the observed response frequency and its precision cannot be evaluated. The results for the listed secondary outcomes are also not reported in the registry record.

The response outcome uses modified International Workshop Response Criteria, and assessment is attributed to an Independent Review Committee. However, the record does not report the committee’s assessment procedures, whether reviewers were masked, how disagreements were resolved, or the timing and frequency of response assessments. The outcome timeframe is described, but the procedures that generated the assessments are not detailed.

The primary analysis set is defined as enrolled participants treated with any amount of study drug. The record does not report the number included in the primary endpoint analysis or how missing or unevaluable responses were handled. It also does not report exclusions, sensitivity analyses, or other analysis-population details. Therefore, the effect of missing assessments or deviations from the described analysis population cannot be assessed.

The statistical plan is not reported in the registry record. In particular, the record does not describe the confidence-interval method, multiplicity procedures, interim analyses, or the original sample-size justification. The planning assumptions described for illustrations do not establish what methods were used in the trial itself.

Safety reporting is limited to group-level counts and selected serious-event terms. The record does not provide details on ascertainment, attribution, observation time by participant, or the full context needed to compare safety across treatments. These limitations narrow what can be concluded from the recorded safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of Bendamustine in the Treatment of Chinese Participants With Indolent Non-Hodgkin Lymphoma Refractory to Rituximab Treatment — NCT01596621.
• Registry record last updated 2023-05-26; status last verified 2023-05.
• Results first posted 2023-05-26.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

The registry record describes NCT01596621, a completed Phase 3, open-label, single-group study of bendamustine hydrochloride in Chinese participants with indolent non-Hodgkin lymphoma refractory to rituximab treatment. Enrollment was 102. Treatment was administered intravenously on Days 1 and 2 of each 21-day cycle, for 6 planned cycles and up to 8 total cycles.

The primary endpoint was ORR, defined as the percentage achieving complete or partial response under modified International Workshop Response Criteria, assessed by an Independent Review Committee. The primary analysis set included enrolled participants treated with any amount of study drug. The ORR result and the listed secondary outcome results are not reported in the registry record.

The bendamustine group lists 30 participants affected by serious adverse events and 99 affected by other adverse events, with 102 at risk for each category. The record also lists selected serious adverse-event terms and percentages. With no comparator group and limited analysis details, these entries are descriptive and do not establish causation or comparative effects.