CAMPath and BELimumab for Transplant Tolerance in Sensitized Kidney Transplant Recipients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for CAMPath and BELimumab for Transplant Tolerance in Sensitized Kidney Transplant Recipients (NCT03591380), a na phase 2 study. The primary outcome is Number of Participants That Are DSA Positive as Measured by Mean Fluorescence Intensity Greater Than Zero for DSA.

2. Clinical Question

3. Trial Design

This phase 2 study, NCT03591380, evaluated belimumab for transplant tolerance in sensitized kidney transplant recipients. The registry lists a single-group model, allocation as not applicable, and no masking. The only listed intervention is belimumab; participants were also described as receiving standard-of-care medications for kidney transplant recipients. Because there is no concurrent control group, the study does not provide a randomized comparison of belimumab with another treatment or with standard care alone.

The registry describes intravenous belimumab at 10mg/kg at transplant on Day 0 and at 2, 4, 8, 12, 16, and 20 weeks after transplant. The planned primary endpoint timeframe is 12 months from transplant. Listed outcomes also cover DSA development, graft survival and function measured using serum creatinine, eGFR, and urine protein, cellular and antibody rejection, and adverse events.

Enrollment was 3. The study started on 2019-05-14, had a primary completion date of 2021-12-03, and is listed as terminated. The reason for termination is not reported in the registry record. Detailed eligibility criteria, recruitment information, and the actual follow-up available for each participant are not reported in the registry record. The planned endpoint timeframe therefore should not be taken as evidence that every participant had complete follow-up to that point.

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 Participants That Are DSA Positive as Measured by Mean Fluorescence Intensity Greater Than Zero for DSA, measured over 12 months from the time of transplant..

The primary endpoint is the number of participants who are DSA positive, with positivity defined as mean fluorescence intensity greater than zero for DSA. The stated timeframe is 12 months from transplant. DSA refers to donor-specific antibodies, the immune response the study aimed to monitor after transplantation. The registry describes Luminex as the method for determining de novo DSA development and says descriptive statistics would be used.

A count endpoint directly describes how many participants meet the stated positivity definition. It is useful for communicating the observed frequency in a small single-group study without implying that the result estimates a treatment effect against a control group. The threshold matters: the endpoint classifies participants using a mean fluorescence intensity greater than zero, rather than presenting a continuous antibody measurement as the primary outcome.

The registry record does not report the observed primary endpoint result. It also does not report participant-level antibody measurements, the number assessed at the endpoint, or how missing endpoint assessments were handled. Consequently, the record does not establish how many participants met the DSA-positive definition at 12 months.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry states that descriptive statistics were intended for de novo DSA development, graft survival and function, and rates of acute cellular and antibody-mediated rejection. Descriptive statistics organize and report observed data, such as counts or measurements, without necessarily testing a treatment hypothesis. The primary endpoint is a count of participants meeting the DSA-positive definition. The registry record does not report the resulting count or a statistical analysis of it.

What does a count endpoint communicate?

A count records the number of participants meeting a specified outcome definition. For an event outcome, that count may be presented with the number assessed so the reader can see the denominator as well as the number experiencing the event. General statistical principle: when a study group is small, a count may be more transparent than a percentage alone, because percentages can appear precise while depending on very few observations. The primary endpoint result and its denominator are not reported in the registry record, so neither can be interpreted for DSA positivity.

Why does the single-group design matter?

The study has one treatment group and no concurrent comparator. Descriptive changes or events within a group can characterize what happened to its participants, but do not provide the same evidence as a comparison between groups. General statistical principle: a comparator helps distinguish an outcome pattern associated with an intervention from background changes and other influences. Since no comparison group is listed, a treatment contrast is not available from this design. The allocation entry is not applicable, and the record describes no masking.

How should uncertainty be understood?

General statistical principle: a confidence interval expresses uncertainty around an estimate by identifying a range of values compatible with the observed data under a chosen statistical method. Its width depends on the data and the method. The registry record does not report a confidence interval for the primary endpoint or explain a method for constructing one. Without the primary outcome count and the number assessed, the uncertainty around the endpoint cannot be evaluated from the registry record.

The registry lists zero analyses. This means no analysis results are listed in the record; it does not establish what analyses may have been conducted outside the information recorded there. The statistical plan, including any inferential model, covariate adjustment, or interim analysis plan, is not reported in the registry record. The record also does not report a justification for the planned sample size.

What do the planning assumptions describe?

The stated sample-size assumptions describe planning illustrations using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrated effect is a stated fraction of the observed effect. For time-to-event calculations, the convention is to report the total number of events using the Schoenfeld method; other calculations are expressed as participants per arm. These are planning illustrations, not observed power, and the two-arm assumptions do not describe the actual single-group trial design. The registry record does not report a trial-specific sample-size justification.

General statistical principle: over-dispersion occurs when observed variability is greater than a model assumes. If present, it can make standard errors and confidence intervals from a model that ignores it too optimistic. The registry record does not identify a dispersion model or report a relevant analysis, so there is no basis for determining whether over-dispersion was assessed in this study. More broadly, the registry’s description of planned descriptive statistics does not specify the analysis details needed to reproduce estimates or assess their 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("Experimental: Belimumab")
n      <- c(3)
events <- c(0)
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  Experimental: Belimumab  3  0  0.0  0.0  70.8  0.0  56.1  0.6  60.2

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and six outcome measures overall. The listed secondary outcomes address DSA development, graft survival and function, rejection, and adverse events. Multiple outcomes can describe different aspects of a study, but they also create multiple opportunities to observe an unusual result. General statistical principle: when a study conducts multiple hypothesis tests, a prespecified strategy may be used to control the chance of misleading findings across those tests. A multiplicity strategy is not reported in the registry record.

The registry’s primary outcome description calls for descriptive statistics. It does not report inferential tests, adjusted analyses, or a hierarchy for interpreting outcomes. The analysis plan, including any prespecified handling of multiple comparisons, is not reported in the registry record. Since the registry lists zero analyses and does not give the primary result, there are no reported outcome estimates on which to assess multiplicity in practice.

Missing-data handling is also not reported in the registry record. The record does not state how participants with unavailable DSA measurements, incomplete graft-function measures, or incomplete follow-up would be handled. The number assessed for each outcome and the reasons for any unavailable measurements are not reported in the registry record. Without those details, the extent and possible influence of missing outcome data cannot be judged.

The analysis population is not defined in the registry record. It does not state whether analyses were intended to include everyone enrolled, only participants who received treatment, or another specified group. The small enrollment makes clarity about assessment and inclusion especially important, but the available record does not describe those procedures. These gaps limit assessment of whether the planned outcomes and any eventual analyses were applied consistently.

12. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: fever (33.3%), escherichia coli bacteremis from uti (33.3%), ureteral revision (33.3%), urine leak (33.3%), klebsiella pneumoniae uti (33.3%).

For the Belimumab group, the registry reports 3 participants at risk for serious adverse events and 2 participants affected. It reports 3 participants at risk for other adverse events and 3 affected. The reported number of deaths is 0. These are participant counts in a group of 3, not comparative estimates against a control group.

The registry lists fever, Escherichia coli bacteremis from UTI, Ureteral Revision, Urine Leak, Klebsiella Pneumoniae UTI, and Pseudomonas Aeruginosa UTI as serious-event terms. Each term is listed with a frequency of 33.3%. The record does not describe the timing, duration, relatedness to treatment, or clinical course for these events. The listed terms should therefore be read as safety-reporting categories, not as evidence that belimumab caused them.

General statistical principle: safety counts in small studies are descriptive and imprecise. They can identify events reported during the study, but cannot reliably characterize uncommon risks or establish comparative safety without an appropriate comparison and fuller context. The registry’s counts do not establish an overall safety conclusion.

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

The record establishes that a phase 2, single-group study of belimumab in sensitized kidney transplant recipients enrolled 3 participants and was terminated. It defines a primary endpoint based on DSA positivity at 12 months and describes planned observation of graft outcomes, rejection, and adverse events. The record also reports serious and other adverse-event counts for the Belimumab group.

It does not report the primary DSA result, so it cannot show how many participants met the endpoint. It also does not report the primary endpoint’s denominator at 12 months, a confidence interval, or an analysis estimating the frequency of DSA development. The registry record therefore does not establish whether DSA developed in the study group at a particular rate.

Because the study has no concurrent control group, the reported observations cannot establish a difference between belimumab and another treatment approach. Even if outcome results were available, a single-group description would not by itself demonstrate that an outcome was caused by the intervention. The registry’s stated objective concerns safety and prevention of new DSA, but an objective is not an observed result.

The safety counts show that adverse events were recorded among participants, including serious events, and that no deaths were reported. They do not establish causation or permit a reliable comparison of risk. The reason for termination and details of follow-up are not reported in the registry record. The most defensible reading is therefore limited: the posted record describes a small, terminated, single-group study and its planned outcomes, while leaving the primary endpoint result and important analytic details unreported.

14. Why This Trial Matters Statistically

This study illustrates an important distinction between a clinical question and the evidence needed to answer it. The question of whether belimumab, used with standard kidney transplant medications, is associated with less de novo DSA is clinically motivated in the registry description. The study design, however, is single-group and has no concurrent comparator. That design can describe outcomes among enrolled participants, but it cannot directly estimate a treatment contrast.

The small enrollment also matters statistically. With 3 participants, outcome counts are highly sensitive to each participant’s experience. Reporting counts alongside denominators is important, and uncertainty should not be obscured by a percentage. The registry does report safety counts, but it does not report the primary DSA count or its denominator at the planned endpoint.

The record further shows why endpoint definitions and analysis details matter. DSA positivity is defined by mean fluorescence intensity greater than zero, and the timeframe is 12 months from transplant. Those details make the intended measurement more specific, yet the result, missing-data handling, and analysis population are not reported. A clearly defined endpoint is necessary for interpretation, but it cannot replace the observed outcome data.

Finally, the trial’s terminated status is relevant context, but the reason is not reported in the registry record. It should not be interpreted as evidence of a safety problem or a lack of effect. Statistically, the record highlights the need to separate study objectives, observed data, and conclusions: the objective describes what investigators sought to assess, while the missing primary result prevents an assessment of the stated endpoint.

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 most consequential limitation is the absence of the primary outcome result in the registry record. Although the endpoint definition and timeframe are stated, the number of participants who were DSA positive and the number assessed are not reported. No estimate or uncertainty interval for the primary endpoint is therefore available in the record.

Enrollment was 3, and the study had no concurrent comparator. This limits both precision and the ability to distinguish an intervention-associated pattern from other influences. The record lists a terminated status but does not report the reason. It also does not report participant-level follow-up, whether every participant reached the 12-month assessment, or how missing observations were handled.

The statistical plan is incomplete in the registry record. The analysis population, sample-size justification, inferential methods, and multiplicity strategy are not reported. The record lists descriptive statistics as the approach for several outcomes and lists zero analyses, but does not provide results for the primary endpoint. Details of event attribution and timing are also not reported for the safety counts.

These limitations prevent a comparative assessment of belimumab and a precise estimate of the frequency of DSA positivity in this study. They also restrict interpretation of the safety information to reported counts and terms, without establishing causation. The limits concern the information and design recorded; they do not establish why the study ended or what findings may exist outside the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: CAMPath and BELimumab for Transplant Tolerance in Sensitized Kidney Transplant Recipients — NCT03591380.
• Registry record last updated 2023-01-09; status last verified 2022-12.
• Results first posted 2023-01-09.
• 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

NCT03591380 is a phase 2, single-group study of belimumab for transplant tolerance in sensitized kidney transplant recipients. The sponsor is University of Wisconsin, Madison. The registry describes intravenous belimumab at 10mg/kg at transplant and at 2, 4, 8, 12, 16, and 20 weeks after transplant, alongside standard-of-care medications.

The primary endpoint is the number of participants DSA positive by mean fluorescence intensity greater than zero at 12 months from transplant. Enrollment was 3. The study started on 2019-05-14, had a primary completion date of 2021-12-03, and is listed as terminated. The reason for termination is not reported in the registry record.

The registry reports 2 participants with serious adverse events, 3 with other adverse events, and 0 deaths. It does not report the primary endpoint result, an analysis result, or key details such as missing-data handling and the analysis population.