Allogeneic SCT Of Pts With SCID And Other Primary Immunodeficiency Disorders: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Allogeneic SCT Of Pts With SCID And Other Primary Immunodeficiency Disorders (NCT00579137), a na phase 1, phase 2 study. The primary outcome is Number of Patients With Donor Engraftment.

2. Clinical Question

3. Trial Design

This was a phase 1 and phase 2, single-group trial of allogeneic stem cell transplantation for participants with SCID or other primary immunodeficiency disorders. The registry lists enrollment of 3 and status as terminated. The recorded study start is 2007-10, and primary completion is recorded as 2009-10. Baylor College of Medicine is listed as the sponsor.

The treatment plan combined donor stem cell infusion with conditioning that included Campath -1H, Fludarabine and Anti-CD45. The arm description states that all participants would receive an allogeneic transplant with this regimen. The brief description discusses related HLA mismatched donors and unrelated matched or mismatched donors as potential sources. The registry record does not report which donor types were actually used for the enrolled participants, or whether the planned regimen was received by each participant.

Allocation is listed as NA, masking as NONE, and the model as SINGLE GROUP. These fields describe a study without a randomized parallel control group or masking. As a result, the design can describe outcomes among treated participants, but it does not create a controlled estimate of how outcomes compare with an alternative regimen. The registry record does not report a statistical analysis plan, a sample-size justification, interim analyses, or reasons for termination. Its status alone does not explain why the study was terminated.

Four outcome measures are recorded: donor engraftment as the primary outcome and three secondary outcomes concerning survival at one year, Grade III or IV toxicity, and Grade III to IV acute GVHD. Results for these outcomes are not reported in the registry record. The small enrollment and lack of a comparator are important context when interpreting the stated objectives: this design is not a randomized test of comparative effectiveness.

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 Number of Patients With Donor Engraftment, measured over 100 Days.

The primary endpoint is the number of participants with donor engraftment, measured at 100 Days. It is recorded as a participant count, so the intended result is a count of participants meeting the study's engraftment criterion, rather than a mean measurement or a time-to-event estimate. The registry record does not define the clinical or laboratory criteria used to determine engraftment, nor does it describe how the assessment was made or how missing assessments would be handled.

In general, engraftment is used as an outcome because it addresses whether donor-derived blood-forming cells become established after transplantation. That makes it relevant to the biological aim of an allogeneic transplant and to whether the planned treatment sequence achieved this early post-transplant milestone. This general rationale does not establish how the trial operationalized the endpoint; its precise definition is not reported in the registry record.

The stated assessment time is 100 Days. A count at a specified time point can be clinically interpretable only alongside a clear denominator, outcome definition and accounting of participants who were not assessed. The registry record does not report the number with engraftment, the number assessed at the stated time, or participant-level outcome data. Therefore, no trial-specific engraftment rate or estimate of precision can be described from the reported record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a binary-count primary outcome: the number of participants with donor engraftment at 100 Days. In general, a count outcome records how many participants meet a defined condition. Interpreting such a count requires knowing both the result and the set of participants considered eligible for the assessment. The registry record gives the planned outcome and time point but not the engraftment definition, observed count, assessed population or missing-outcome handling.

What does a single-group design estimate?

In general, a single-group study describes outcomes among participants who receive the study regimen. It can report the observed frequency of an outcome if the outcome data and denominator are available. It does not, by itself, show what would have happened to comparable participants under a different regimen. That contrast requires a suitable comparator and an analysis designed to estimate the difference. This record lists no comparator arm and identifies the trial as SINGLE GROUP, so a treatment-versus-control effect is not available from the design as recorded.

The registry lists allocation as NA and masking as NONE. Allocation concerns how participants are assigned to treatment groups; masking concerns whether participants or study personnel are kept unaware of assigned treatment. With a single group and no masking, the record does not describe randomized assignment or blinded outcome assessment. These features do not automatically invalidate descriptive counts, but they matter for claims about comparative effects and can be relevant to how outcomes are assessed. The record does not describe safeguards or procedures for outcome assessment.

What would precision mean?

In general, a confidence interval expresses uncertainty around an estimated quantity under a specified statistical method. A narrow interval indicates greater precision than a wide interval, while neither width nor location alone resolves possible bias or limitations in the design. For a participant count or proportion, precision depends in part on the amount of observed information and on the number of participants assessed. No confidence interval for engraftment or the secondary outcomes is reported in the registry record, and the outcome count needed to describe an observed proportion is also absent.

The enrollment of 3 makes the limited information base particularly important. In a small study, each participant's outcome can have a substantial effect on the group summary. General statistical reasoning therefore cautions against treating a descriptive result from a very small group as a stable estimate for a wider population. This is not a recalculation of the trial result: the registry does not report the primary outcome count from which such a result could be described.

Why is the endpoint definition important?

General endpoint methodology distinguishes the label of an outcome from its operational definition. “Donor engraftment” names the event of interest, but analysis also requires criteria that determine whether a participant counts as having the event, the assessment window, and rules for participants whose status is unknown. The record specifies 100 Days as the timeframe but does not report the criteria or missing-data rules. Without those details, readers cannot determine whether another study's engraftment definition would be directly comparable.

The outcome is recorded as a number of participants, rather than a time-to-event endpoint. In general, a fixed-time count asks whether the condition was met by a stated assessment point. A time-to-event analysis instead uses information about when an event occurs and may account for differing follow-up, subject to its assumptions. The registry does not report a time-to-event analysis for engraftment, and none should be inferred from the endpoint label.

What can be inferred from the adverse-event counts?

General safety summaries distinguish participants who experienced an event from the total number considered at risk. The record reports 0 affected by serious adverse events among 3 at risk and 3 affected by other adverse events among 3 at risk. These are participant counts, not event counts: the record does not state how many separate events occurred in each affected participant. It also does not list the serious event terms or provide participant-level timing, duration or attribution. A count alone cannot establish whether events were related to a treatment or how they should be clinically interpreted.

The registry lists other planned safety outcomes, including Grade III or IV toxicity and Grade III to IV acute GVHD. Their outcome results are not reported. Those listed outcomes should not be treated as if they were measured, absent, or equivalent to the adverse-event categories unless the registry reports that relationship. The posted serious and other adverse-event counts do not fill in the missing results for those named secondary outcomes.

What statistical plan is available?

General trial analysis planning can include a target estimand, endpoint definitions, analysis population, missing-data rules, model choice, confidence intervals, multiplicity procedures and planned interim reviews. These elements determine how results are turned into estimates and how uncertainty is presented. A statistical plan is not reported in the registry record. It is therefore not possible to attribute a particular model, adjustment, hypothesis test, imputation method or interim analysis to this trial.

The record lists no analyses. That means no trial analysis results are available in the registry record, rather than establishing what analyses may or may not have occurred elsewhere. Without reported estimates and methods, recalculation from summary statistics is not possible. Any general statistical explanation should not be mistaken for a description of procedures used in this trial.

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("Single Group")
n      <- c(3)
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  Single Group  3  1  33.3  0.8  90.6  6.1  79.2  6.8  80.6

11. Multiplicity, Missing Data and Analysis Populations

The record identifies a primary outcome and three secondary outcomes: patients alive at one year, number of patients with Grade III or IV toxicity, and number of patients with Grade III to IV acute GVHD. Considering multiple outcomes can raise a general multiplicity issue: when several outcomes are examined, the chance of at least one apparently notable result can increase if each is assessed separately. Methods such as prespecifying a primary outcome, defining an outcome hierarchy or adjusting inference can address particular multiplicity concerns. Whether any such approach was planned or used is not reported in the registry record.

The primary outcome is donor engraftment at 100 Days, but its result is not reported. Results for the secondary outcomes are also not reported. The record does not provide hypothesis tests, confidence intervals, or an analysis plan that would show whether these outcomes were descriptive or part of formal statistical testing. Accordingly, no multiplicity-adjusted or unadjusted inference can be reconstructed from the registry record.

Missing-data methods and analysis populations are also not reported. The registry does not state how many participants had an evaluable primary outcome, whether any outcome assessments were missing, or how participants without an assessment would be handled. It does not specify whether analyses were intended to include all enrolled participants, only participants who received the regimen, or another defined group. With enrollment of 3, these distinctions could matter to the interpretation of any count, but the record does not permit them to be resolved.

The study status is TERMINATED, but the reason, timing and consequences of termination for outcome collection are not reported in the registry record. It would be inappropriate to infer that termination caused missing results or that a particular analysis was stopped early. Interim analyses and stopping criteria are not reported in the registry record.

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 adverse-event summary records 0 participants affected by serious adverse events among 3 at risk. It also records 3 participants affected by other adverse events among 3 at risk. These are participant-level counts in the registry summary; they do not indicate the number of distinct events, since one participant could experience more than one event. The registry record does not list the serious adverse-event terms or provide details of the other events.

The record does not report deaths in the adverse-event summary. It also lists Grade III or IV toxicity and Grade III to IV acute GVHD as secondary outcomes, but does not report results for either outcome. Those omissions should not be interpreted as evidence that no such events occurred. The meaning of the serious and other adverse-event categories, including event attribution and reporting period, is not detailed in the registry record. These counts describe what is recorded and do not establish whether an event was caused by the regimen or how severe the full safety experience was.

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

The record establishes that a phase 1/phase 2, single-group study was intended to evaluate allogeneic stem cell transplantation with conditioning that included Campath -1H, Fludarabine and Anti-CD45 in participants with SCID or other primary immunodeficiency disorders. It reports enrollment of 3 and identifies donor engraftment at 100 Days as the primary outcome. It also records adverse-event counts and names three secondary outcomes.

Those details do not establish the trial's engraftment result. The number of participants with donor engraftment is not reported in the registry record, and the endpoint criteria and assessment completeness are likewise absent. Results for survival at one year, Grade III or IV toxicity and Grade III to IV acute GVHD are not reported. Without those results, readers cannot determine the observed outcomes for the trial's stated endpoints from this record.

The design also does not support a controlled comparison. No separate comparator group is listed, so the study cannot, on the basis of this record, estimate how outcomes would differ under another conditioning regimen. Even a reported outcome count would describe the enrolled group rather than establish a causal treatment effect. The very small enrollment further limits the precision and generalizability of any descriptive estimate.

The adverse-event figures should be read narrowly: 0 of 3 participants at risk were recorded as affected by serious adverse events, and 3 of 3 were recorded as affected by other adverse events. These entries do not identify the events or establish their causes. They cannot substitute for missing results on the named toxicity and GVHD outcomes.

In general, a registry entry is a record of study information and may not contain a full statistical report. In this case, the statistical plan, outcome results, analysis populations and missing-data procedures are not reported in the registry record. The appropriate interpretation is therefore limited to the design and counts actually documented; stronger conclusions about safety, engraftment or comparative effects are not supported by the posted information.

14. Why This Trial Matters Statistically

Statistically, this trial illustrates the difference between a clinically important question and the evidence needed to answer it. Donor engraftment is the stated primary outcome, and the study aimed to examine transplantation after a specific combination of conditioning agents. Yet the registry record does not report the primary outcome count. Without that count, its denominator and a clear endpoint definition, even a descriptive estimate cannot be reconstructed.

The single-group design also defines the scope of inference. It can potentially describe outcomes among participants receiving the regimen, but it does not provide a randomized comparison with another regimen. This distinction matters because an observed outcome in a treated group does not by itself establish that the regimen caused the outcome or performed differently from an alternative. The allocation field is NA and no separate control group is recorded.

Enrollment of 3 emphasizes how limited the information base is for estimating outcomes or characterizing uncommon events. General statistical principles indicate that small groups yield uncertain estimates, and each participant's outcome can strongly shape a summary. That limitation is separate from the registry's lack of reported endpoint results: even if outcomes were available, their precision and scope would need careful consideration.

The record also demonstrates why reporting methods and populations matters. A named endpoint and timeframe do not fully specify how an outcome was assessed, how missing observations were handled, or which participants were included in an analysis. Those details are not reported. Nor is a statistical plan available to explain how the primary and secondary outcomes were to be interpreted together. These omissions limit reproducibility and make comparisons with other studies difficult.

The statistical importance of the record lies in defining these boundaries. It documents a treatment strategy and a small single-group study, while leaving the principal outcome and key analysis details unreported. Keeping descriptive evidence distinct from comparative evidence prevents the design from being asked to support conclusions it cannot establish.

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.

This trial's recorded enrollment is 3, which sharply limits the amount of outcome information that could be available from the enrolled group. The study is single-group and has no separate comparator, so it cannot provide a direct controlled estimate of outcomes relative to another regimen. Its status is TERMINATED, but the reason for termination is not reported in the registry record, so its implications for follow-up or outcome collection cannot be assessed.

The primary outcome is named as donor engraftment at 100 Days, but the observed count, endpoint criteria and assessment completeness are not reported. The registry likewise does not report results for its secondary outcomes: patients alive at one year, Grade III or IV toxicity, and Grade III to IV acute GVHD. The record does not give participant-level data or an analysis population from which to examine differences by diagnosis or donor type.

Details needed to evaluate analysis quality are also absent. A statistical analysis plan, missing-data procedures, interim analyses, sample-size justification and reasons for termination are not reported in the registry record. The record does not state which donor types were used among enrolled participants, how outcomes were assessed, or whether the planned conditioning regimen was completed by every participant.

Safety interpretation is limited to the recorded counts: 0 affected by serious adverse events among 3 at risk and 3 affected by other adverse events among 3 at risk. Event terms, timing, attribution and the relationship to the named toxicity outcomes are not reported. The registry entry therefore supports only a narrow description of the recorded design and counts, not a full assessment of efficacy, safety or comparative effects.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Allogeneic SCT Of Pts With SCID And Other Primary Immunodeficiency Disorders — NCT00579137.
• Registry record last updated 2013-07-02; status last verified 2013-06.
• Results first posted 2013-07-02.
• 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 a phase 1/phase 2, single-group study sponsored by Baylor College of Medicine, with enrollment of 3 and status TERMINATED. It concerns allogeneic stem cell transplantation for SCID or other primary immunodeficiency disorders, using conditioning that included Campath -1H, Fludarabine and Anti-CD45. The primary outcome is the number of participants with donor engraftment at 100 Days.

The record lists three secondary outcomes concerning survival at one year, Grade III or IV toxicity, and Grade III to IV acute GVHD. It reports 0 participants affected by serious adverse events among 3 at risk and 3 affected by other adverse events among 3 at risk. Primary and secondary outcome results, the statistical plan, analysis populations and missing-data procedures are not reported in the registry record. With no separate comparator group, the design is descriptive rather than a controlled comparison.