This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Study Comparing Zevalin Regimen With no Further Treatment in Patients With Diffuse Large B-cell Lymphoma. (NCT00322218), a randomized phase 3 study. The primary outcome is Overall Survival (OS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00322218 |
| Phase | Phase 3 |
| Condition | Lymphoma, Large Cell, Diffuse |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 68 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Spectrum Pharmaceuticals, Inc |
| Results posted | Yes |
2. Clinical Question
Population
Patients with diffuse large B-cell lymphoma whose disease was in complete remission after previous treatment with CHOP-R. The registry record describes the study population in those terms; further eligibility details are not reported in the registry record.
Intervention
The intervention was the Zevalin therapeutic regimen. The arm description begins with rituximab followed by ibritumomab tiuxetan, but the regimen details in the registry record are incomplete.
Comparator
The comparator was no further anti-lymphoma therapy. Participants in the observation arm remained free of anti-lymphoma therapy and were followed for relapse.
Primary question
The primary question was whether overall survival differed between the Zevalin and observation groups during follow-up described as 5 years or until death or loss to follow-up. The registry record defines overall survival as time from randomization to death from any cause, but says that outcome data are unavailable.
Disease-free survival and health-related quality of life were listed as secondary outcomes. The record therefore describes a comparison of post-remission treatment with observation across survival and other outcomes, but it does not provide results that answer whether the groups differed.
3. Trial Design
This was a randomized, open-label, parallel-group, multicenter study listed as phase 3. It compared a Zevalin regimen with no further treatment among patients with diffuse large B-cell lymphoma in complete remission after CHOP-R. The recorded enrollment was 68. The brief summary says that half of the patients received Zevalin and half received no additional anti-cancer therapy; the adverse-event record lists 34 participants at risk in each group.
The Zevalin arm received the named drug regimen. The registry description includes some initial administration details, but the regimen text is incomplete, so the full treatment schedule cannot be reconstructed from the record. The observation arm did not receive reference therapy and was followed for relapse during a long-term follow-up stage. The arm description gives a median observation period of 5 years for that stage.
Masking was listed as none, so the study was open-label. The record gives a start date of 2006-05 and a primary completion date of 2008-12. Its current status is terminated, and the description says the study was completed in 2008. The reason for termination is not reported in the registry record.
Random allocation is relevant because, in general, it is intended to make treatment groups comparable with respect to factors that could influence outcomes. It does not substitute for outcome reporting: without the survival data or the sponsor’s analysis, the record cannot establish the direction or precision of any group difference. Details of the randomization procedure, allocation concealment, and the planned statistical analysis beyond the stated endpoint description 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: Of the 151 screened patients 68 patients were assigned to treatment (Full analysis set, FAS). Three patients showed major protocol deviations and thus were excluded from the "per protocol set"(PPS). The PPS comprised 65 patients.
Overall Study
| Stage | Zevalin | Observation |
|---|---|---|
| STARTED | 34 | 34 |
| Per-Protocol Set | 33 | 32 |
| COMPLETED | 31 | 28 |
| NOT COMPLETED | 3 | 6 |
Reasons for not completing this period:
| Reason | Zevalin | Observation |
|---|---|---|
| Death | 3 | 6 |
Analysis population for the primary outcome, as defined in the registry: This study was completed in 2008. We have exhausted all efforts and unfortunately, the data cannot be located in our records. Therefore, no data is available to report for this outcome measure.
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.
| Characteristic | Unit | Zevalin | Observation | Total |
|---|---|---|---|---|
| Participants analysed | 34 | 34 | 68 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 | 6 | 9 |
| Age, Categorical: >=65 years | Participants | 31 | 28 | 59 |
| Age, Continuous | years | 70.2 (SD 4.6) | 68.8 (SD 4.8) | 69.5 (SD 4.7) |
| Sex: Female, Male: Female | Participants | 21 | 19 | 40 |
| Sex: Female, Male: Male | Participants | 13 | 15 | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Overall Survival (OS), measured over 5 years or until patient dies or lost to follow up.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was overall survival, defined in the registry record as the time interval from randomization to death from any cause. The timeframe was 5 years or until a participant died or was lost to follow-up. For participants still alive at their last known follow-up visit, the endpoint was censored at that visit.
In general, overall survival is a time-to-event measure: it incorporates both whether an event occurred and when it occurred. Death from any cause is the event, while censoring records that an event had not been observed by a participant’s last known follow-up. A censored observation does not mean that the participant was known to remain alive indefinitely; it means follow-up ended without a recorded death by that point.
The registry says that overall survival was analyzed with Kaplan-Meier estimates by treatment group. It also defines the endpoint in terms of median time to death, but no group-specific survival estimates, medians, or other outcome values are available in the posted results. The record states that the study was completed in 2008 and that the data could not be located despite efforts to find them. Consequently, the endpoint’s meaning is described, but its observed value and the comparison between groups cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record does not report an overall-survival result. It says that the study was completed in 2008, that efforts to locate the data were exhausted, and that no data are available for this outcome measure. Although the endpoint and its analysis are described, there is no reported survival estimate for either group and no reported estimate of a between-group difference.
That absence must not be interpreted as evidence that the groups had the same survival, or that either group had better survival. It is an absence of outcome information in the registry record. Without the underlying event and follow-up information or the sponsor’s analysis, the direction, size, and precision of any survival difference are unknown. No confidence interval, hypothesis-test result, or group-specific median is reported for the primary endpoint.
The analysis description names Kaplan-Meier estimates for the full analysis set and the per-protocol set. It defines the full analysis set as identical to the safety analysis set, but the registry does not give survival estimates for either population. The description also explains that participants alive at the last known follow-up were censored at that time. This analysis approach does not recover results when the underlying outcome data are unavailable.
The adverse-event counts are separate descriptive information and do not fill the gap in the primary endpoint. The record lists serious adverse events affecting 2 of 34 participants in the Zevalin group and 1 of 34 in the observation group. It lists other adverse events affecting 5 of 34 and 1 of 34, respectively. These counts do not provide a survival comparison, and the registry record does not give enough detail to interpret them as adjusted or causal comparisons.
The study’s randomized design and stated comparison define the intended clinical question, but they do not make the result recoverable from the record. The record supports describing the design, endpoint definition, and posted adverse-event counts. It does not support a conclusion about the primary outcome or a claim that one strategy did or did not change survival.
9. Statistical Methods Explained
The registry record describes the primary analysis as based on the full analysis set and says that overall survival was analyzed in both the full analysis set and the per-protocol set using Kaplan-Meier estimates by treatment group. It defines the full analysis set as identical to the safety analysis set. The record does not report the participant-level data or the resulting estimates, so the named methods can be explained but their application cannot be independently evaluated.
What does a Kaplan-Meier estimate describe?
In general, the Kaplan-Meier method estimates the pattern of time to an event while allowing follow-up to end before the event is observed for some participants. For overall survival, the event is death from any cause. The method uses each participant’s recorded event or censoring time to estimate the probability of remaining alive over follow-up. A curve or estimate can describe the timing of events, but its precision depends on the amount and timing of available follow-up and events.
The registry says that survival time was censored at the date of the last known follow-up visit when a participant was still alive. In general, censoring retains information up to the last known observation; it does not treat a censored participant as having died at that point. Interpretation also depends on assumptions about censoring and on accurate follow-up information. The record does not report details that would allow those assumptions or follow-up completeness to be assessed.
Why is the endpoint time-to-event?
In general, a time-to-event endpoint includes information about when an event occurs, not only whether it occurred during follow-up. Participants may have different follow-up durations, and some may have no observed event before follow-up ends. Methods designed for time-to-event data can account for these features through censoring. The primary endpoint description specifies a time origin at randomization and an event of death from any cause. It does not provide the observed survival data needed to estimate the treatment-group patterns.
What do the analysis populations mean?
The full analysis set and per-protocol set are named in the record, but their membership rules are not described. In general, a full analysis population aims to preserve the randomized comparison, while a per-protocol population typically focuses on participants meeting specified study requirements. The exact definitions vary by protocol, so those general descriptions should not be taken as the study’s undocumented rules. The registry states only that its full analysis set was identical to the safety analysis set. It does not report the analysis population sizes or explain how deviations, withdrawals, or missing observations were handled.
Looking at more than one analysis population can help readers understand how conclusions may depend on analysis choices. It does not by itself establish robustness. Here, no population-specific survival results are reported, so there is no basis for comparing the two analyses.
How should uncertainty and significance be assessed?
In general, a confidence interval describes the range of values compatible with an estimate under the statistical model and its assumptions. A hypothesis test assesses compatibility with a specified null hypothesis. Neither can be interpreted without a reported estimate and its uncertainty or test result. The registry record does not report a confidence interval, p-value, hazard ratio, or other quantitative comparison for overall survival. It also does not report the planned statistical hypothesis or significance threshold for the primary analysis.
The sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. For time-to-event planning, the description says that the total number of events is used. Such illustrations are planning calculations, not observed power and not evidence about the trial’s actual result. The trial’s own sample-size justification and design assumptions are not reported in the registry record. No planning illustration can replace the missing outcome analysis.
What can the posted safety counts establish?
In general, adverse-event counts describe events recorded under a study’s collection and reporting rules. Counts alone do not show whether an event was caused by an intervention or whether groups differed beyond chance. Interpretation also depends on definitions, observation periods, participant exposure, and completeness of reporting. The registry lists serious and other adverse-event counts by group but does not provide all of those details. The counts should therefore be read descriptively, not as a substitute for the unavailable survival analysis or as a causal estimate.
10. Multiplicity, Missing Data and Analysis Populations
The record lists overall survival as the primary outcome and lists disease-free survival and health-related quality of life as secondary outcomes. It does not report a multiplicity strategy for interpreting several outcomes, time points, or analyses. In general, when multiple statistical questions are assessed, the chance of at least one apparently notable result can increase unless the analysis plan accounts for that multiplicity. The record does not state whether any adjustment, hierarchy, or other prespecified approach was used.
The primary endpoint timeframe is described as 5 years or until death or loss to follow-up. The record does not give separate outcome estimates across follow-up time points. It also does not report results for the listed secondary outcomes, so their findings and any relationship to the primary analysis cannot be assessed.
For overall survival, the registry describes censoring at the last known follow-up visit for participants who were alive. This defines one part of the endpoint handling, but other missing-data procedures are not reported in the registry record. In particular, the record does not describe how loss to follow-up was addressed in the analysis or provide information on the extent of missing outcome information. It states that no data are available for the primary outcome because the study was completed in 2008 and the data could not be located.
The full analysis set is described as identical to the safety analysis set, and the per-protocol set is also named for the survival analysis. Membership rules and handling of protocol deviations are not reported in the registry record. Without those definitions and the outcome data, it is not possible to judge whether the reported analysis populations were implemented as intended or whether alternative missing-data assumptions would affect the results.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Zevalin | 2 | 34 | 5.9% |
| Observation | 1 | 34 | 2.9% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Zevalin | 5 of 34 |
| Observation | 1 of 34 |
Most frequent serious adverse event terms
| Event term | Organ system | Zevalin | Observation |
|---|---|---|---|
| cytopenia | Blood and lymphatic system disorders | 2 of 34 | 1 of 34 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Zevalin | Observation |
|---|---|---|---|
| Infections and manifestations | Infections and infestations | 5 of 34 | 1 of 34 |
Serious events with the highest arm-level rate: cytopenia (5.9%).
The registry record lists serious adverse events affecting 2 of 34 participants in the Zevalin group and 1 of 34 in the observation group. It separately lists other adverse events affecting 5 of 34 and 1 of 34, respectively. These are descriptive counts as recorded; the record does not give enough information about event definitions, collection windows, severity rules, or exposure to support a fuller comparison.
Cytopenia is listed among the top serious terms at 5.9%. The record does not identify the group associated with that term in the available description, so it should not be assigned to either arm. The death counts are not reported in the registry record.
In general, a count of participants with an event is not proof that the intervention caused it. Nor do these figures alone account for the timing, duration, recurrence, or clinical context of events. They should be read as the safety information posted in the registry, not as a comprehensive safety analysis or a substitute for the unavailable overall-survival results.
12. What the Result Does, and Does Not, Mean
The record establishes that a randomized, open-label comparison was planned between the Zevalin regimen and observation for patients in complete remission after CHOP-R. It also gives the primary endpoint definition and says that Kaplan-Meier estimates were used by treatment group. Those details clarify the question the study was intended to address, but they do not establish what the study found.
The central limitation is that the registry reports no data for the primary outcome. It states that the study was completed in 2008, that efforts to locate the data were exhausted, and that no outcome data are available to report. As a result, there is no reported survival estimate, treatment-group comparison, or measure of precision to interpret. The absence of a result is not evidence that survival was equal, and it is not evidence of benefit or harm.
The listed adverse-event counts offer limited descriptive safety information, but they do not answer the survival question. The registry also lists disease-free survival and health-related quality of life as secondary outcomes without reporting their results. The reason the study was terminated, the full statistical plan, and details of missing-data handling are not reported in the registry record.
In general, a randomized design can support a fair comparison when its allocation, follow-up, analysis, and outcome reporting are available. Here, randomization and the intended endpoint are known, but the missing outcome data prevent readers from evaluating the primary comparison. The appropriate interpretation is therefore about the limits of the record: the clinical question is identifiable, while the result remains unavailable. No conclusion that Zevalin or observation changed outcomes follows from the posted information.
13. Why This Trial Matters Statistically
This trial illustrates an important distinction between a study’s design and its evidential result. Randomization specifies how the comparison was intended to be formed, and the endpoint definition specifies what outcome was to be measured. Neither is a substitute for the observed outcomes and the statistical estimates needed to assess the comparison.
The overall-survival endpoint is a time-to-event measure, so interpretation depends on both event times and follow-up information. The registry describes Kaplan-Meier estimation and censoring, but does not report the data or estimates. This makes the trial a clear example of why analysis methods alone cannot answer a clinical question: readers need the results and enough information to evaluate their precision and assumptions.
The record also shows why missing outcome reporting should not be read as a null result. No reported estimate means the direction and magnitude of the group difference are unknown. It does not establish equivalence or lack of effect. That distinction matters when a registry entry includes a detailed study description but lacks the outcome information needed for inference.
Finally, the safety counts demonstrate the limited role of isolated descriptive figures. They can convey what the registry lists, but without fuller definitions and analysis they do not resolve the primary question. The statistical importance of this record is therefore less about a treatment estimate than about transparent interpretation: design, endpoint, analysis description, and available results are separate pieces of evidence, and the last is missing for the primary outcome.
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 main limitation is explicit: the registry says that no primary-outcome data are available because the study was completed in 2008 and the data could not be located despite efforts. The record consequently contains no reported overall-survival estimates, uncertainty intervals, or test results. The primary question cannot be answered from the posted results.
The status is terminated, but the reason for termination is not reported in the registry record. The record gives a primary completion date of 2008-12 and describes the study as completed in 2008; these entries do not explain why the study was terminated or whether termination affected follow-up or reporting.
Several design and analysis details are not reported in the registry record, including the randomization procedure, allocation concealment, eligibility criteria beyond the remission description, the full Zevalin regimen, sample-size justification, and the planned statistical analysis. The record names the full analysis set and per-protocol set but does not define their membership rules. Multiplicity handling and broader missing-data procedures are also not described.
The adverse-event information is limited to posted counts and a serious-term listing. Event definitions, collection periods, exposure details, and group attribution for the listed cytopenia percentage are not given in the available description. These limits mean that the counts should not be treated as a complete comparative safety analysis. The secondary outcomes are named but their results are not reported.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study Comparing Zevalin Regimen With no Further Treatment in Patients With Diffuse Large B-cell Lymphoma. — NCT00322218.
- Registry record last updated 2022-01-19; status last verified 2022-01.
- Results first posted 2022-01-19.
- 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.
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18. Record Summary
The registry record describes a randomized, open-label, parallel-group, multicenter study comparing the Zevalin regimen with observation in patients with diffuse large B-cell lymphoma in complete remission after CHOP-R. Recorded enrollment was 68, and the study is listed as terminated. Its primary outcome was overall survival, defined as time from randomization to death from any cause, with censoring at the last known follow-up for participants still alive.
The record says overall survival was analyzed using Kaplan-Meier estimates in the full analysis set and per-protocol set. It also states that the full analysis set was identical to the safety analysis set. However, the primary outcome data could not be located, and no result is available to report. Disease-free survival and health-related quality of life were listed as secondary outcomes, with no results reported in this record.
Serious and other adverse-event counts are listed by group, but the record does not provide enough detail for a full comparative safety interpretation. The reason for termination and several protocol and analysis details are not reported in the registry record.