Mechanisms of Belatacept Effect on Alloimmunity and Antiviral Response After Kidney Transplantation (BMS IM 103-309): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Mechanisms of Belatacept Effect on Alloimmunity and Antiviral Response After Kidney Transplantation (BMS IM 103-309) (NCT01953120), a na phase 4 study. The primary outcome is Antibody and T Cell-mediated Immune Response.

2. Clinical Question

The study record gives enrollment as 20 and identifies renal transplant rejection as a condition. Its stated focus is not simply a comparison of rejection rates: it also concerns immune responses after a treatment switch, including laboratory-based measures and clinical outcomes. Those clinical outcomes included CMV viremia, PTLD, donor specific antibodies, acute rejection, and death. The record does not give results for these outcomes in the posted analysis information.

As a general statistical point, a single-group study can describe what was observed among enrolled participants, but cannot by itself separate a treatment effect from changes that could occur over time or from other influences. It also cannot establish how outcomes would have differed under an alternative treatment without a suitable comparison. Accordingly, the central question addressed by the recorded design is descriptive: what immune and clinical outcomes were assessed following conversion to belatacept? A comparative question about whether belatacept is better than another medicine is not answered by this study design.

3. Trial Design

The registry identifies this as a completed Phase 4 study sponsored by the University of California, Los Angeles. It records a single-group model, allocation as NA, and no masking. Enrollment is listed as 20. The start is recorded as 2013-10 and primary completion as 2021-04. These design details describe the registry entry; they do not establish how many participants contributed data to each outcome.

The intervention is belatacept. The arm description refers to survival and rejection in patients switched to belatacept, while the primary outcome description specifies conversion from CNI in patients with evidence of CNI toxicity. It also describes belatacept as maintenance immunosuppression in combination with prednisone and mycophenolate mofetil. The registry does not provide a detailed schedule of treatment or follow-up in the registry record recorded for this analysis.

There is no recorded control arm. The brief summary mentions cyclosporine and tacrolimus as other medicines used in the broader clinical context, but the study design does not assign participants to either as a concurrent comparator. The summary's language about evaluating whether belatacept is better than other medicines should therefore not be read as evidence that this registry entry contains a randomized comparative test. The record explicitly notes that the arms are not a like-for-like control comparison.

Masking is listed as none. This indicates that the registry does not describe a masked design; it does not tell the reader whether particular outcome assessors or laboratory procedures had any separate safeguards against knowledge of treatment. Such details are not reported in the registry record.

The primary outcome timeframe is Month 6. The outcome title concerns antibody and T cell-mediated immune response, while the description also mentions safety, efficacy, laboratory assessments, and clinical outcomes. The registry lists two outcome measures but no analyses. A detailed protocol, analysis plan, participant flow, and the number contributing to each endpoint are not reported in the registry record. Completion status indicates that the study is marked completed, but does not itself indicate that results were analyzed or posted.

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

Analysis population for the primary outcome, as defined in the registry: Clinical outcomes measured included CMV viremia, PTLD, development of donor specific antibodies, acute rejection, and death. Laboratory based measurements included immune phenotype, alloimmune response as measured by intracellular cytokine stimulation (ICS), and antiviral immune response to CMV and EBV as measured by ICS.

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 Antibody and T Cell-mediated Immune Response, measured over Month 6.

The primary outcome is titled Antibody and T Cell-mediated Immune Response. Its unit is participants, its parameter is a number, and its timeframe is Month 6. The description states that the study aimed to examine the effect of switching from CNI to belatacept on the development and maintenance of immune memory in response to alloantigen and viral antigens commonly encountered after transplant. It also describes assessment of safety and efficacy for conversion to belatacept as maintenance immunosuppression with prednisone and mycophenolate mofetil.

The record lists clinical outcomes including CMV viremia, PTLD, donor specific antibodies, acute rejection, and death. Laboratory-based measurements included immune phenotype, alloimmune response assessed using intracellular cytokine stimulation, and antiviral immune response to CMV. The laboratory description ends before specifying its full scope. The registry does not report a precise definition of a participant counted as having the primary outcome, nor does it give the primary outcome result.

As a general statistical point, immune-response measures can provide information about biological processes that clinical event outcomes may not capture directly. A participant count is interpretable only when the event or response criteria, observation period, and population counted are clear. Without the operational definition and posted results, the title and description establish the intended subject of measurement but do not show the magnitude, direction, or precision of any observed immune response.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design show?

The registry describes a single-group study without a concurrent control arm. In general, this design can document what was observed after an intervention in the studied participants. It cannot, on its own, distinguish the intervention's effect from other explanations for changes over time. For example, the observed course may also reflect participants' underlying health, prior treatment, follow-up practices, or events unrelated to the intervention. These are general design considerations, not claims about what occurred in this study.

A comparative treatment effect requires a contrast between outcomes under the intervention and outcomes under an appropriate alternative. Random allocation can help make such groups comparable on average, while a suitable observational comparison requires explicit methods and assumptions. Neither a comparator group nor a comparative analysis is recorded. The study's stated interest in other anti-rejection medicines does not turn those medicines into a study control.

Why does the endpoint definition matter?

The primary outcome title refers to antibody and T cell-mediated immune response, and the description discusses immune memory and laboratory assessments. In general, a title is not a complete measurement specification. To interpret a participant count, readers need to know what qualifies as a response or event, how the measurement is made, which threshold defines a positive result, and how measurements are handled when results are incomplete. Those details are not reported in the registry record.

The timeframe is Month 6. Timeframes help define when the outcome is assessed, but do not by themselves explain whether events occurring earlier or later are counted, how repeated measurements are summarized, or whether participants must have a measurement at the specified visit. The registry record does not report those operational details. The clinical and laboratory outcomes listed in the description also represent different kinds of information and should not be treated as interchangeable measures.

How should counts and uncertainty be read?

For a binary outcome, a count of participants with an event is ordinarily interpreted alongside the number whose outcome status could be assessed. The count alone does not show the frequency of the event without its denominator. In this record, the primary outcome has no posted result, and outcome-specific denominators are not reported. The enrollment entry should not be presumed to be the denominator for every measure.

As a general statistical concept, a confidence interval describes uncertainty around an estimate under specified assumptions. Wider intervals generally indicate less precision, while narrower intervals indicate greater precision. The interval does not account automatically for every source of bias, such as an unsuitable comparison group, incomplete outcome measurement, or a poorly defined endpoint. No primary-outcome confidence interval is reported in the registry record, so the precision of that outcome cannot be evaluated from the posted information.

A p-value, when reported, summarizes how compatible observed data are with a specified null model under the assumptions of the analysis. It does not measure the probability that a treatment works, and it does not convey the size or clinical importance of an effect. The registry lists no analyses, so it supplies no p-value or inferential result for the primary outcome. It would not be appropriate to infer a result from the study's completion status or enrollment.

What can a single-group safety count establish?

The registry reports serious adverse event and other adverse event counts for the Belatacept group, together with deaths. Such counts are useful descriptive information about what the registry lists, but their interpretation depends on the definitions used, ascertainment procedures, follow-up duration, and completeness of reporting. The detailed definitions and follow-up exposure for these safety summaries are not reported in the registry record.

As a general point, observing no reported events in a group does not prove that the underlying event risk is absent. Limited observation, incomplete reporting, or chance can affect whether an event is seen. A comparative safety claim would also require an appropriate comparator and a defined analysis; neither is provided in the recorded study design. The listed counts therefore should be read as registry-reported observations, not as proof of no risk or evidence of superiority.

What analysis plan is available?

The registry lists two outcome measures and no analyses. It does not report a statistical analysis plan, model specification, handling of repeated laboratory measurements, covariate adjustment, missing-data procedure, or analysis population. The record also does not state whether any interim analyses occurred or give a sample-size justification. These details cannot be reconstructed from the outcome title or study status.

As a general statistical principle, a prespecified plan helps readers distinguish planned analyses from choices made after seeing the data. It can also clarify which outcomes are primary, how multiple outcomes are handled, and how missing observations affect the estimates. In the absence of a reported plan and posted outcome analyses, these questions remain open. No unadjusted recalculation or planning illustration is reported in the registry information summarized for this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and identifies the primary outcome as Antibody and T Cell-mediated Immune Response. It also describes multiple clinical outcomes and laboratory measurements. The statistical analysis plan, the hierarchy of secondary outcomes, and any procedure for controlling multiplicity are not reported in the registry record. Therefore, it is not possible to determine how the study planned to distinguish confirmatory findings from exploratory ones or how multiple statistical tests, if any, were addressed.

As a general statistical point, testing several outcomes can increase the chance that at least one result appears notable by chance. Prespecified outcome hierarchies or multiplicity adjustments can help address that issue, but the registry does not document whether either approach was used. No analyses are listed, so the record gives no test results to interpret in light of multiplicity.

Missing-data methods and analysis populations are also not reported in the registry record. The enrollment entry does not identify how many participants had a Month 6 primary outcome measurement, whether participants were excluded from any outcome analysis, or how unavailable measurements were handled. The record does not state whether analyses used all enrolled participants, participants who received treatment, or another defined population. These omissions limit assessment of selection bias, completeness, and the precision of any outcome estimate.

As a general matter, missingness can affect interpretation when the availability of measurements is related to participants' outcomes or health. Complete-case analysis, imputation, and other approaches rely on different assumptions; the record does not identify an approach. Without participant flow, outcome-specific denominators, or a missing-data description, the extent and potential impact of missing information cannot be assessed.

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 0% reporting threshold.

The registry reports safety information for the Belatacept group. Serious adverse events are listed with 20 at risk and 0 affected. Other adverse events are also listed with 20 at risk and 0 affected. Deaths are recorded as 0. These are descriptive registry counts, not comparisons between treatments.

The record does not provide event-level terms among the top serious-event terms, and the definitions and ascertainment details are not reported in the registry record. The at-risk figures should be read as the registry's reported group counts; the record does not establish that each safety figure corresponds to the same follow-up duration or completeness of observation as every other outcome.

As a general statistical point, zero reported events do not establish that an event cannot occur or that risk is absent. The ability to characterize uncommon harms depends on the amount and duration of observation and on complete event reporting. A treatment comparison would require a suitable comparator and an analysis of between-group uncertainty. This record supplies neither for safety. The figures therefore describe what was recorded in the group, without demonstrating comparative safety.

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

The record establishes that a completed Phase 4, single-group study examined belatacept after a switch from CNI in kidney transplant patients with evidence of CNI toxicity. Its primary outcome concerns antibody and T cell-mediated immune response, with a Month 6 timeframe. The stated research aims also include immune memory, safety, efficacy, laboratory measures, and clinical outcomes. These details describe what the study set out to assess.

The record does not report the primary outcome results or analyses. It therefore does not quantify the observed immune response or its uncertainty. The registry lists no analyses, and outcome-specific denominators and missing-data methods are not reported. The available information cannot establish whether the primary outcome changed, how large any change was, or how precisely it was measured.

The design also does not provide a concurrent treatment comparator. As a general statistical point, observations after a treatment switch cannot by themselves show what outcomes would have occurred under a different treatment. The brief summary's discussion of other medicines is background, not a control-group result. The registry entry therefore does not support a comparative conclusion about belatacept versus cyclosporine, tacrolimus, or another alternative.

The safety counts report 0 affected for serious adverse events and 0 affected for other adverse events, with deaths recorded as 0. These figures are limited to the registry's descriptive reporting and should not be interpreted as proof that no risk exists. The record does not provide comparative safety estimates or detailed event terms.

In general, statistical interpretation depends on the outcome definition, the participants contributing data, the analysis method, and an assessment of uncertainty. Those elements are not reported sufficiently to draw conclusions about treatment effects from this record. The results that can be stated are consequently limited to the study's design and the safety counts that were posted.

13. Why This Trial Matters Statistically

This study is statistically notable for the gap between its broad research aims and the limited analysis information in the registry record. The stated aims span immune memory, laboratory measurements, clinical events, safety, and efficacy. Yet the record lists no analyses and does not report a result for the primary immune-response outcome. Readers can identify what the research intended to assess, but cannot evaluate the size or precision of the reported primary finding.

The single-group design is also central to interpretation. It can document outcomes among participants who underwent the switch to belatacept, but it does not supply a concurrent counterfactual group. As a general statistical principle, treatment effects are comparative: they concern how outcomes differ under alternative strategies. Without that contrast, even a well-measured outcome would be descriptive rather than a direct estimate of comparative benefit or harm.

The registry's distinction between a study's background motivation and its actual design matters. The brief summary raises comparison with other anti-rejection medicines, while the recorded allocation and model identify no comparative arm. Statistical interpretation should follow the design actually recorded, not infer a comparison from the motivating question.

The safety information illustrates why counts require context. Zero affected participants are reported for the listed adverse-event categories, but no comparator, detailed event terms, or analysis of uncertainty is recorded. As a general matter, a descriptive absence of reported events is not equivalent to evidence that risk is absent. The study record is most useful for identifying the clinical and laboratory questions pursued, the single-group structure, and the limits on inference created by unreported analyses and outcome details.

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 trial-specific limitation is the single-group design. Allocation is listed as NA, masking as none, and the record identifies no concurrent control. This prevents a direct within-study comparison with another anti-rejection treatment. The brief summary mentions cyclosporine and tacrolimus, but the registry does not record either as a comparator arm.

The primary outcome is named, but its operational definition and result are not reported. The stated Month 6 timeframe does not supply the response criteria, measurement thresholds, or rules for classifying participants. The laboratory description includes immune phenotype, intracellular cytokine stimulation, and antiviral immune response to CMV, but does not give a complete measurement specification in the recorded information.

The registry lists two outcome measures and no analyses. It does not report the statistical analysis plan, participant flow, outcome-specific denominators, analysis populations, missing-data handling, or methods for multiplicity. These omissions prevent evaluation of how results were calculated, whether all relevant participants were included, and how uncertainty or multiple outcomes were addressed.

Enrollment is listed as 20, but this should not be treated as the number analyzed for each outcome. The record does not report the number contributing data at Month 6 or the completeness of follow-up for clinical and laboratory measures. The posted serious adverse-event information is also limited: detailed event terms are absent, and the record does not give the methods or duration underlying those summaries.

Finally, completed status does not itself establish that results were analyzed or reported. Taken together, the record gives useful design and research-purpose information, but limited material for judging outcome magnitude, precision, or comparative treatment effects.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Mechanisms of Belatacept Effect on Alloimmunity and Antiviral Response After Kidney Transplantation (BMS IM 103-309) — NCT01953120.
• Registry record last updated 2022-12-13; status last verified 2022-11.
• Results first posted 2022-12-13.
• 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

NCT01953120 is a completed Phase 4, single-group study sponsored by the University of California, Los Angeles. The registry lists enrollment as 20, allocation as NA, and masking as none. The intervention is belatacept, described for patients switched from CNI after kidney transplantation in the context of evidence of CNI toxicity.

The primary outcome, Antibody and T Cell-mediated Immune Response, has a Month 6 timeframe. The study description includes immune memory, laboratory assessments, and clinical outcomes such as CMV viremia, PTLD, donor specific antibodies, acute rejection, and death. The record lists two outcome measures and no analyses, and does not report primary outcome results, outcome-specific denominators, or a statistical analysis plan.

For the Belatacept group, the registry reports 20 at risk and 0 affected for serious adverse events, 20 at risk and 0 affected for other adverse events, and deaths recorded as 0. These are descriptive counts without a concurrent comparator. The record supports interpretation of the study's design and intended questions, but not a comparative treatment-effect conclusion.