Rituximab, Fludarabine, Mitoxantrone, Dexamethasone (R-FND) Plus Zevalin for High-Risk Follicular Lymphoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Rituximab, Fludarabine, Mitoxantrone, Dexamethasone (R-FND) Plus Zevalin for High-Risk Follicular Lymphoma (NCT00290511), a na phase 2 study. The primary outcome is Number of Participants With Time to Progression (TTP).

2. Clinical Question

The study was designed to assess a multi-step strategy rather than isolate the contribution of any one drug. Its stated objectives also include assessing tolerance and efficacy of Zevalin after R-FND, overall response, failure-free survival, survival, and maintenance rituximab. Another objective is to maximize the 12-month molecular remission rate and examine how quantitative PCR results relate to classical PCR and clinical outcome.

The comparison with a historical expectation is important to the interpretation. It gives the target a clinical and statistical context, but it is not equivalent to a contemporaneous control group assigned to a different treatment. Differences between the study participants and the historical experience, or in how outcomes were assessed, could affect such comparisons. The registry record does not describe the historical cohorts in enough detail to assess their comparability.

The primary question concerns time until progression, not simply the proportion of participants who respond at one assessment. The record defines complete and partial response criteria, but the stated primary objective is whether median time to progression reaches its target. The numerical primary outcome result is not reported in the registry record, so the stated question cannot be answered from the recorded outcome information alone.

3. Trial Design

This is a phase II, single-group study sponsored by M.D. Anderson Cancer Center. The registry record lists an enrollment of 49 and a completed status. The recorded start date is 2004-06-29 and the primary completion date is 2021-02-12. The allocation is listed as NA, and masking is listed as none. There is no randomized, concurrent comparison group described.

The treatment strategy is R-FND followed by Zevalin and then maintenance rituximab. The listed drugs are fludarabine, mitoxantrone, rituximab, Zevalin, and dexamethasone. The arm description gives some dosing and timing details for R-FND and maintenance rituximab, including rituximab every other month for 12 months, but the recorded description is incomplete. Details beyond those stated are not reported in the registry record.

The primary outcome is titled “Number of Participants With Time to Progression (TTP),” while its description says time to progression is measured using the Kaplan-Meier method and accompanied by a 95% confidence interval. The assessment schedule begins at baseline and includes evaluations after courses of treatment and at later follow-up intervals, with follow-up continuing until progressive disease or loss to follow-up. The listed timeframe also describes an average of 10 years.

The study objectives make clear that the investigators were interested in both disease control and treatment tolerance. Secondary outcomes include maintenance-treatment tolerance and efficacy, median progression-free survival, progression-free survival at 10 years, overall survival, and the percentage of participants with overall survival at 10 years. The registry record lists seven outcome measures, but it does not include numerical results for the primary endpoint or these secondary outcomes in the registry record for interpretation.

Because this is a single-group study, the observed course of participants can describe outcomes under the treatment strategy but cannot by itself establish what would have happened to similar participants under another strategy. Historical experience is named as context, but details of a formal comparative analysis 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.

Before assignment: Forty-nine patients with Follicular Lymphoma were enrolled in this single site, phase II trial. Two patients were removed after registration and did not start treatment: the first, due to physician's decision; the second, to pursue treatment at home.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Time to Progression (TTP), measured over baseline, 2 and 4 courses, approximately month 8, 9, and 12 months, then restaging every 4 months, then at 2 years every 4-6 months, then yearly until progressive disease or lost to follow up, average of 10 years.

Time to progression (TTP) measures the time from a defined starting point until disease progression. The registry description says TTP was assessed using the Kaplan-Meier method and accompanied by a 95% confidence interval. It also describes a schedule of baseline and follow-up assessments, continuing until progressive disease or loss to follow-up. The precise operational details of the time origin and the handling of events other than progression are not reported in the registry record.

The stated primary objective uses the median TTP as its measure of whether the regimen meets the study’s target. The record defines success as prolonging median TTP to 36 months or greater, against a historical expectation of approximately 24 months. A median is a time-to-event summary: in general, it identifies the point by which the estimated event-free proportion has reached one half. It is not the average time to progression, and it does not describe every participant’s course.

Time-to-event methods are useful when follow-up durations differ or some participants have not experienced the event by their last observation. In general, Kaplan-Meier estimation can use information up to the last known follow-up for those participants, rather than treating their follow-up as if progression had occurred. The estimate still depends on sound event and follow-up recording and on the assumptions appropriate to censoring.

The endpoint is clinically relevant to the stated objective because it focuses on how long progression is delayed, rather than response alone. However, the registry record does not provide the observed median, its confidence interval, or a numerical account of the primary outcome. The target and method are described, but the result needed to judge the target is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a time-to-event primary outcome and identifies the Kaplan-Meier method with a 95% confidence interval. These are appropriate concepts to understand the stated analysis, but the numerical estimate and interval are not reported in the registry record. The method description alone cannot show the observed time to progression or how uncertain that estimate is.

What does Kaplan-Meier estimation do?

In general, Kaplan-Meier estimation uses the timing of events and follow-up to estimate the probability of remaining free of the event over time. A participant who has not had progression by the end of observed follow-up can contribute information up to that point, after which the observation is censored. Censoring is not the same as a progression event. The validity of the estimate depends on appropriate recording of event times and on assumptions about why follow-up ends. The registry record does not describe the detailed censoring rules or how such cases were handled.

The reported endpoint description refers to progressive disease or loss to follow-up and gives a schedule of repeated assessments. It does not state how missed assessments, ambiguous progression dates, or other events were treated. These operational choices can matter for time-to-event analyses, particularly when progression is assessed at scheduled visits rather than observed continuously. The specific rules are not reported in the registry record.

How should the median and confidence interval be read?

In general, the median from a Kaplan-Meier curve is the time at which the estimated probability of remaining free of progression reaches one half. It is a summary of the estimated distribution, not a statement that every participant has the same time to progression. A 95% confidence interval communicates sampling uncertainty around the estimated quantity under the statistical method used. It does not mean that the true value has a 95% probability of lying within a particular fixed interval once the data have been observed. Here, the record says a confidence interval was to accompany the estimate, but the median and interval are not reported in the registry record.

The stated criterion is median TTP of 36 months or greater, with an historical expectation of approximately 24 months. Those values define the study’s stated benchmark. They do not substitute for the actual estimate or its uncertainty. Nor does the registry record state a test result, a p-value, or an inferential procedure for formally comparing the observed median with the benchmark.

What does a single-group design allow?

In general, a single-group study can characterize outcomes observed among participants receiving a strategy. Without a concurrent control group, it cannot separate the treatment effect from other explanations for the observed course. Historical comparisons can be informative, but their interpretation depends on whether populations, eligibility, outcome assessment, follow-up, and other relevant conditions are sufficiently comparable. The registry record refers to historical experience with FND alone or R-FND but does not report the details needed to assess comparability or a formal adjustment for differences.

The treatment is a sequence of several components: R-FND, Zevalin, and maintenance rituximab. As a result, outcomes under the strategy cannot identify the independent contribution of each component. This is a general limitation of evaluating a multi-component regimen without groups receiving different components or sequences.

What do the planning assumptions mean?

The record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; time-to-event illustrations use the total number of events, while other illustrations use participants per arm. These are described as planning assumptions, not as the trial’s own design. The study itself is single-group, so a two-arm illustration should not be mistaken for an observed comparison or for the design actually used. The calculated planning values are not reported in the registry record described in the registry record for this analysis.

In general, a planning sample size is an estimate of the number of observations needed under stated assumptions to detect a specified effect with a chosen probability. Such a calculation does not describe the probability that a completed study has found a real effect. That latter concept is often called observed power, and it should not be inferred from a planning illustration or from the presence of a statistically significant result. The registry record does not report a trial-specific sample-size justification, target power, or statistical plan, so those details cannot be inferred from the planning assumptions.

Why does the confidence interval matter?

In general, a confidence interval provides information about precision that a point estimate alone cannot convey. A narrow interval indicates greater precision under the model and assumptions; a wide interval indicates less precision. For a time-to-event endpoint, interval width can depend on the number and timing of events as well as follow-up. No primary estimate, confidence interval, or event count for TTP is reported in the registry record, so precision cannot be evaluated from the available outcome details.

Statistical interpretation also depends on whether analyses follow prespecified definitions and populations. The registry record does not report the analysis population for the primary endpoint, any exclusions from analysis, the detailed statistical analysis plan, or whether any interim analyses were conducted. Those points are not recoverable from the stated endpoint method alone.

10. Multiplicity, Missing Data and Analysis Populations

The study names several objectives and outcomes in addition to time to progression, including response, failure-free survival, molecular remission, progression-free survival, overall survival, and tolerance of treatment. When multiple outcomes or analyses are examined, the chance of finding at least one apparently notable result can increase. In general, multiplicity procedures can control or describe that issue, but the registry record does not report a multiplicity adjustment or a hierarchy among the secondary outcomes.

The record describes the primary objective and its target, but a detailed statistical analysis plan is not reported in the registry record. It does not specify whether the primary analysis was prespecified in a protocol, how secondary analyses were to be interpreted, or how any repeated or subgroup analyses were handled. The record lists zero analyses, and numerical outcome analyses are not included in the registry record.

Missing-data and analysis-population details are also not reported in the registry record. The endpoint timeframe refers to follow-up until progressive disease or loss to follow-up, but it does not explain the censoring rules, how missing assessments were addressed, or whether participants were analyzed according to an intention-to-treat or another population definition. The enrollment is listed as 49, but the record does not give a primary-outcome analysis denominator or explain any difference between enrollment and the number contributing to an endpoint analysis.

These omissions do not demonstrate that the study lacked procedures; they mean the registry record does not document them in the information available for interpretation. Without analysis-population definitions, missing-data methods, and multiplicity details, readers cannot fully evaluate the robustness of the outcome analyses even if numerical results are available elsewhere.

11. 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 1% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: neutropenia (42.9%), thrombocytopenia (32.7%), fatigue (16.3%), pain (12.2%), dyspnea (10.2%).

The safety record lists one treatment group, R-FIND + Zevalin. It reports 49 participants at risk for serious adverse events and 34 affected. For other adverse events, it lists 49 at risk and 46 affected. The record also gives 8 deaths. These are separate recorded counts; they should not be added together, as participants can experience more than one type of event and the record does not establish whether categories overlap.

The listed serious adverse event terms are neutropenia (42.9%), thrombocytopenia (32.7%), fatigue (16.3%), pain (12.2%), dyspnea (10.2%), and blurred vision (6.1%). The registry record presents these as the top serious terms. The percentages describe the entries as reported, but the record does not provide further detail on grading, duration, timing, or attribution. It also does not specify whether one participant could contribute to more than one listed term.

These counts and terms should be read as safety observations in a single-group study, not as proof that the treatment caused each event or that a particular event was caused by one component of the sequence. There is no concurrent control group for comparing event rates. Details about the relationship between the listed deaths and adverse events, or the causes of death, are not reported in the registry record.

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

The study addresses a clinically important statistical question: whether a multi-component treatment strategy could meet a stated median time-to-progression target in advanced follicular lymphoma with high-risk features. The registry record identifies the population, treatment sequence, endpoint method, and target. It also records safety counts and selected serious adverse event terms.

Those details do not amount to a numerical finding on the primary question. The observed median TTP and its 95% confidence interval are not reported in the registry record. Therefore, the available information cannot establish whether the 36-month target was met, how precisely TTP was estimated, or how the outcome compared with the historical expectation of approximately 24 months.

Even if a single-group estimate were available, it would describe outcomes observed during this strategy rather than provide a randomized estimate of benefit relative to another strategy. Historical comparisons can provide context, but their interpretation depends on comparability and measurement details that are not reported in the registry record. Since treatment was given as a sequence, the design also cannot isolate the contribution of R-FND, Zevalin, or maintenance rituximab.

The adverse-event counts indicate that serious and other adverse events were recorded, and the registry lists several serious event terms with percentages. These observations are relevant to the study’s safety objective, but they do not by themselves determine causation, comparative safety, or the balance of benefits and harms. The registry record does not report enough detail about event timing, severity, attribution, or the deaths to resolve those questions.

The broader objectives include response, survival, progression-free survival, and molecular remission. Their numerical results are not reported in the registry record. The appropriate interpretation is consequently limited: the registry describes what the investigators aimed to evaluate and some safety observations, but does not provide the primary efficacy result or the full outcome information needed to judge the strategy.

13. Why This Trial Matters Statistically

This study illustrates why a clear endpoint definition and a clearly stated benchmark are valuable. The primary objective identifies time to progression and specifies a target median of 36 months or greater, against a historical expectation of approximately 24 months. That makes the research question interpretable in principle: the focus is on the duration until progression, rather than on response alone.

It also illustrates why method descriptions and results must be read separately. Naming Kaplan-Meier estimation and a 95% confidence interval tells readers how the primary outcome was described analytically, but it does not reveal the estimate, its precision, or whether the target was reached. The numerical endpoint result is not reported in the registry record, so the statistical question remains unanswered in the available record.

The single-group design is another instructive feature. It can document the course of participants who receive a multi-step treatment strategy, but it cannot provide a concurrent randomized contrast. A historical expectation can motivate a phase II study, yet it leaves open whether differences in participant mix, follow-up, or outcome assessment might explain a contrast. Those details are not reported in the registry record.

Finally, the study’s many stated objectives show why outcome hierarchy, multiplicity, missing-data handling, and analysis-population definitions matter. The record identifies several areas of interest, but does not report the details of those statistical procedures or numerical results for the broader outcomes. For biostatisticians and clinical researchers, this case underscores that a registry’s stated objective, design, and outcome reporting each answer different questions. A complete interpretation requires the estimated effects, uncertainty, and analysis context—not merely a target and a method label.

14. Limitations

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

The principal limitation for interpreting efficacy is the absence of numerical primary-outcome results. The median TTP, its 95% confidence interval, and the number of progression events are not reported in the registry record. As a result, the stated target cannot be assessed from the recorded outcome information.

The study has a single-group design and no concurrent control. Although historical expectations and prior experience are named, the registry record does not provide details of the historical participants, their outcome definitions, or their follow-up. A direct comparison with those historical experiences therefore cannot be evaluated from the registry entries. In general, a historical benchmark may not account for changes in population, assessment, or care over time.

The intervention is a sequence comprising R-FND, Zevalin, and maintenance rituximab. Without groups assigned to different components or sequences, the outcome of the whole strategy cannot identify which element contributed to any observed result. The arm description is also incomplete in the registry record, limiting a full reconstruction of the regimen from that description.

Further outcome interpretation is constrained because numerical results for response, failure-free survival, molecular remission, progression-free survival, and overall survival are not reported in the registry record. Details of the primary analysis population, missing-data rules, censoring procedures, multiplicity handling, interim analyses, and statistical analysis plan are also not reported in the registry record. The safety information lists counts and selected terms but does not document event grading, timing, attribution, or the relationship between deaths and adverse events.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Rituximab, Fludarabine, Mitoxantrone, Dexamethasone (R-FND) Plus Zevalin for High-Risk Follicular Lymphoma — NCT00290511.
• Registry record last updated 2022-04-22; status last verified 2022-03.
• Results first posted 2022-04-22.
• 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.

18. Record Summary

NCT00290511 is a completed phase II, single-group study sponsored by M.D. Anderson Cancer Center. It enrolled 49 participants with advanced stage III-IV follicular lymphoma and high-risk features. The treatment strategy was R-FND followed by Zevalin and subsequent maintenance rituximab; masking is listed as none.

The primary objective was to assess whether median time to progression could reach 36 months or greater, with an historical expectation of approximately 24 months. The record describes Kaplan-Meier estimation with a 95% confidence interval, but the numerical primary result is not reported in the registry record. It also lists secondary objectives involving response, survival, molecular remission, and treatment tolerance.

For the listed treatment group, the safety record reports 34 participants affected by serious adverse events, 46 affected by other adverse events, and 8 deaths. Selected serious adverse event terms and percentages are recorded. A concurrent comparator and detailed analysis methods are not reported in the registry record.