S0501 Fludarabine, Melphalan, and Donor Stem Cell Transplant Followed By Tacrolimus and Methotrexate in Treating Patients for Relapsed Lymphoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for S0501 Fludarabine, Melphalan, and Donor Stem Cell Transplant Followed By Tacrolimus and Methotrexate in Treating Patients for Relapsed Lymphoma (NCT00121186), a na phase 2 study. The primary outcome is Progression-free Survival.

2. Clinical Question

3. Trial Design

This is a phase II study registered as a single-group trial with no masking. Allocation is listed as not applicable, and the record describes one nonmyeloablative allogeneic stem cell transplant approach rather than randomized treatment arms. Enrollment is listed as 1. The study status is terminated. The start is recorded as 2005-07 and primary completion as 2008-01.

The registered regimen includes fludarabine 30 mg/m^2 on days -6 to -2 and melphalan 70 mg/m^2 on days -3 and -2, followed by a donor stem cell transplant on day 0. The donor cells could be peripheral blood stem cells or harvested bone marrow stem cells. Tacrolimus and methotrexate are listed as post-transplant immunosuppressive interventions. The arm description ends during the tacrolimus dosing text, so a complete dosing schedule is not reported in the registry record.

The primary outcome is progression-free survival, described as the PFS rate at 1 year. The assessment schedule lists 1, 3, and 12 months after protocol treatment, then every 3 months for 1 year, every 6 months for year 2, and annually thereafter until 5 years after registration. The registry record does not report a statistical analysis plan, a target enrollment rationale, or results for the primary outcome. The enrollment figure and terminated status make it especially important not to read the record as a comparative estimate of treatment effects.

4. Participant Flow and Accounting

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

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Progression-free Survival, measured over 1, 3, and 12 months after protocol treatment, then every 3 months for 1 year, every 6 months for year 2, then annually thereafter until 5 years after registration.

The primary endpoint is progression-free survival, with the registry describing the primary measure as the PFS rate at 1 year. In general, progression-free survival concerns the time a participant remains alive without disease progression. A rate at a specified time summarizes the proportion meeting that status at the landmark, while a time-to-event analysis can use information about when progression or death occurs and account for follow-up duration.

The registry lists assessments at 1, 3, and 12 months after protocol treatment, with later assessments continuing on the stated schedule through 5 years after registration. Those time points describe planned outcome follow-up; they do not establish that observations were collected at every point. The record’s endpoint unit is participants and its parameter is a number, but it does not provide an observed PFS count, rate, or time-to-event estimate. The outcome definition’s detailed rules for progression, censoring, and handling of deaths are not reported in the registry record.

PFS is used in clinical research to summarize disease control while also accounting for death as an event, according to the study’s prespecified definition. Here, the registry record does not provide that full operational definition or any result, so the endpoint’s intended meaning can be described, but its observed value and precision cannot be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical interpretation begins by distinguishing the design from the outcome. This record describes a single-group phase II study, not a randomized comparison. In general, a single-group study can describe outcomes among participants who receive an intervention, but it cannot directly estimate a between-group treatment effect without a suitable comparator. The registry record lists enrollment of 1, so even a complete outcome report would describe a very limited amount of experience.

What does the endpoint represent?

Progression-free survival is generally a time-to-event outcome. The event is commonly defined using disease progression or death, but the exact event definition and rules for censoring must come from the study’s protocol or analysis plan. Those details are not reported in the registry record. The primary outcome is described as the PFS rate at 1 year, and the record lists a number of participants as the endpoint unit. No actual count, rate, or time-to-event estimate is reported.

A landmark rate and a time-to-event analysis are related but not identical summaries. A landmark rate asks what status participants have reached by a specified time, whereas a time-to-event method can use event timing and account for participants whose follow-up ends before an event is observed. In general, censoring means that follow-up ends without the event being observed during the available observation period; it does not establish that the event would never occur. The registry does not describe how censoring was handled or whether a time-to-event method was used.

What can uncertainty measures tell readers?

In general, a confidence interval expresses the range of estimates compatible with the data under a specified statistical procedure. Its width reflects uncertainty and depends on the amount and structure of information available, along with modeling assumptions. A very small study generally offers little information for estimating an outcome precisely. No confidence interval or other uncertainty measure for PFS is reported in this record, so precision cannot be assessed from the registry entry.

A p-value, when reported, measures how compatible the data are with a specified null model under the assumptions of the test. It is not the probability that a treatment works, and it does not convey the size or clinical importance of an effect. The registry lists no analyses, and no p-value for the primary endpoint is reported. No inferential result should be inferred from the endpoint description or the study status.

How should the sample-size illustrations be read?

The accompanying planning calculations are described as illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For non-time-to-event outcomes, the stated convention is participants per arm; for time-to-event outcomes, it is the total number of events. These assumptions describe a hypothetical planning exercise. They do not describe the actual single-group design recorded for this trial, and the registry does not report a usable observed PFS effect from which to assess the calculations. Planning illustrations are not observed power and should not be presented as a property of the trial’s results.

In general, over-dispersion occurs when outcome variability exceeds what a simple statistical model assumes. If present, it can make standard errors and uncertainty estimates from an overly simple model misleading. The registry record does not report a model, variance estimate, or evidence about over-dispersion for this study; therefore, this concept is relevant only as a general methodological caution, not as a demonstrated feature of these data.

What analysis choices remain unknown?

The record does not report a statistical analysis plan, an analysis population, a missing-data approach, or a detailed endpoint definition. It also does not say how participants who discontinue follow-up would be handled, whether analyses were adjusted, or how outcomes at different assessment times would be summarized. These omissions limit reproducibility: readers cannot reconstruct a primary analysis or determine whether the posted endpoint description matches the analysis actually performed.

There is no reported randomized comparison, so methods for balancing baseline characteristics between treatment groups are not applicable to the design as recorded. At the same time, the single-group design does not remove the need to define the outcome, follow-up, and analysis population clearly. Since results and analysis details are not reported, statistical interpretation should remain descriptive: the record identifies a planned PFS endpoint and follow-up schedule, but supplies no basis for estimating its observed value or 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("Nonmyeloablative Allogeneic Stem Cell Transplant")
n      <- c(1)
events <- c(1)
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  Nonmyeloablative Allogeneic Stem Cell Transplant  1  1  100.0  2.5  100.0  20.7  100.0  15.8  98.7

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists two outcome measures, but it does not report analyses for either one. It does not identify a hierarchy of outcomes, a method for controlling multiplicity, or whether any outcomes were designated exploratory. When multiple outcomes or repeated tests are examined, the chance of a chance-positive finding can increase; statistical plans sometimes address this by prioritizing outcomes or adjusting inference. That is a general issue, not evidence that a particular adjustment was or was not used in this study.

The primary outcome is identified as the PFS rate at 1 year, but the registry record does not report a result or an analysis population. It does not state whether all enrolled participants, participants who started treatment, or another defined group would be included in an analysis. The population field for the endpoint contains no description. These omissions make it impossible to determine which participants would contribute to a reported estimate.

Missing outcome data, loss to follow-up, and the handling of incomplete assessments are not reported in the registry record. In general, missingness can affect interpretation when participants with unavailable outcomes differ from those with observed outcomes. An analysis plan may specify censoring, imputation, or sensitivity analyses, but none of those methods is reported. The registry also does not state whether interim analyses were planned or conducted.

Because the record reports no endpoint analysis, there is no basis for judging multiplicity control, missing-data handling, or the relationship between planned and analyzed populations. These are unknown reporting details, not evidence that a particular method was omitted from the study’s conduct.

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 non-serious adverse event terms

The registry’s adverse-event figures list a serious-event category with 1 at risk and 0 affected. A separate other-event category lists 1 at risk and 1 affected. These are the posted counts; they do not provide enough detail to identify the event types or their clinical course. No top serious adverse-event terms are listed.

The death count is not reported in the registry record. It should not be interpreted as zero. The record also does not provide definitions for the serious and other categories, event timing, severity grades, attribution to treatment, or details on how events were collected. Without those details, the counts cannot establish the nature, cause, duration, or clinical importance of the events.

These safety figures are descriptive and do not support a comparison with another treatment, because the study is single group and no comparator is listed. With enrollment of 1, the counts also give only a narrow account of the participants represented in this registry entry. They should be read as the posted adverse-event data, not as a complete assessment of safety or as evidence about the frequency of events in a broader population.

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

The record establishes that a phase II, single-group study of a nonmyeloablative allogeneic stem cell transplant approach was registered for relapsed lymphoma after autologous transplantation. It identifies the treatment components, the PFS endpoint, and the planned outcome-assessment schedule. It also reports enrollment of 1 and a terminated status. These registry entries describe the study’s registration and scope; they do not provide its primary outcome result.

The record does not show an observed PFS rate at 1 year, an estimate of uncertainty, or a comparison with another treatment. It therefore cannot establish whether outcomes were better or worse than they would have been under an alternative approach. A single-group design would not, on its own, provide a controlled estimate of treatment effect, and the very limited enrollment further restricts what could be learned about outcome variation.

The absence of a posted result is not itself evidence of no effect, harm, or treatment failure. The registry record does not report why the study was terminated, whether follow-up was completed, or what happened to the enrolled participant. Nor does it report an analysis plan or the handling of incomplete data. Those gaps prevent a fuller interpretation.

The appropriate statistical reading is narrow: the registry documents a planned clinical question and records limited enrollment, but provides no reported efficacy estimate on which to base a quantitative conclusion. The adverse-event counts are also sparse and lack event descriptions and a reported death count, so they do not support broad safety conclusions. No clinical recommendation follows from these registry entries.

14. Why This Trial Matters Statistically

This study illustrates why design and reporting context matter when reading a clinical result. PFS is a meaningful time-to-event concept, but naming an endpoint is not the same as reporting an estimate. Without the observed outcome, an uncertainty measure, and a clear analysis method, readers cannot assess the magnitude or precision of the result.

The single-group design is equally important. Without a concurrent comparison group, outcomes cannot be interpreted as a direct estimate of how the intervention compares with another strategy. Enrollment of 1 further limits the information available for describing outcomes and safety. These features are not resolved by a planning calculation that assumes a different design.

The registry also highlights the distinction between planned assessment and reported evidence. It provides a follow-up schedule extending through 5 years after registration, but does not establish whether all assessments were completed or analyzed. A terminated status and a primary completion date do not explain why the study ended or what was learned. Transparent reporting of participant flow, endpoint definitions, analysis populations, missing-data handling, and results would be needed to answer those questions.

For biostatistical interpretation, the central lesson is to separate a trial’s stated purpose from what its reported data can support. Here, the registry conveys the intended clinical question and treatment approach, but not a PFS estimate or inferential analysis. That distinction prevents planned endpoints, sparse adverse-event counts, or sample-size illustrations from being mistaken for evidence of treatment effect.

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 registry record contains limited information for evaluating either efficacy or safety. It reports enrollment of 1 but does not describe participant characteristics, eligibility details, treatment receipt, follow-up completion, or participant-level outcomes. The reason for termination is not reported in the registry record. The recorded primary completion date does not establish that the planned endpoint was fully collected or analyzed.

The primary endpoint is named, but its detailed definition is not reported. The record does not specify operational criteria for progression, the treatment of death, censoring rules, or whether the primary summary was based on a landmark status or a time-to-event analysis. Although a follow-up schedule is listed, the record does not report how observations at those times were used statistically.

The analysis plan, analysis population, and missing-data approach are not reported in the registry record. No primary outcome result or uncertainty estimate is available. The record lists two outcome measures but reports no analyses, and it does not describe multiplicity handling or interim analyses. The endpoint population field is blank.

The intervention description is also incomplete: the arm description ends during the post-transplant tacrolimus dosing text. While the listed interventions include tacrolimus and methotrexate, the full dosing details are not reported in the registry record. The adverse-event counts lack event terms and detailed definitions, and the death count is not reported. Together, these limits prevent a reproducible assessment of the study’s clinical outcomes and statistical methods.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: S0501 Fludarabine, Melphalan, and Donor Stem Cell Transplant Followed By Tacrolimus and Methotrexate in Treating Patients for Relapsed Lymphoma — NCT00121186.
• Registry record last updated 2012-04-03; status last verified 2012-03.
• Results first posted 2012-04-03.
• 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

NCT00121186 is a phase II, single-group study sponsored by SWOG Cancer Research Network. It registered a nonmyeloablative allogeneic stem cell transplant approach for relapsed lymphoma after autologous transplantation, using fludarabine and melphalan before donor stem cell transplantation and tacrolimus and methotrexate afterward. The record lists enrollment of 1, a start date of 2005-07, primary completion in 2008-01, and terminated status.

The primary endpoint is the PFS rate at 1 year, with follow-up scheduled through 5 years after registration. No primary outcome result or analysis is reported. The adverse-event record lists 0 affected in the serious category and 1 affected in the other category, each with 1 at risk; the death count is not reported. The entry does not provide enough information to estimate treatment effects, assess precision, or make a comparative safety assessment.