A Study of Experimental Medication BMS-986251, Taken by Mouth, in Healthy Participants and Patients With Average to Very Serious Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Experimental Medication BMS-986251, Taken by Mouth, in Healthy Participants and Patients With Average to Very Serious Psoriasis (NCT03329885), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants That Experienced the Following: Serious Adverse Events (SAEs), Death or an Adverse Event (AE) Leading to Study Discontinuation.

2. Clinical Question

The study examined oral BMS-986251 in healthy participants and patients with moderate-to-severe psoriasis. Its stated primary outcome concerns the number of participants experiencing serious adverse events, death, or an adverse event leading to study discontinuation. The record also describes pharmacokinetic and pharmacodynamic objectives, and an efficacy assessment in the psoriasis part, but does not provide inferential analyses of those objectives.

This is a safety-focused question, rather than a single efficacy comparison. The primary outcome combines several event categories and gives different assessment periods for adverse events and serious adverse events in Parts A and B. The registry record does not give a single combined estimate or an inferential comparison between BMS-986251 and placebo. It also does not report the primary outcome results for the psoriasis part. As a result, the posted information supports a descriptive reading of the reported safety counts, but not a conclusion about comparative effects or psoriasis efficacy.

3. Trial Design

The registry describes a randomized, quadruple-masked, parallel study with Phase 1 and Phase 2 components. Enrollment was 38. The study began on 2017-11-02, and its primary completion date was 2018-06-26. Its status is terminated; the reason for termination is not reported in the registry record.

The protocol description separates the study into three parts. Part A was a single-ascending-dose study in healthy participants, with single escalating oral doses of BMS-986251 or placebo. Part B was a multiple-ascending-dose study in healthy participants, with daily escalating oral doses of BMS-986251 or placebo. Part C was a multiple-dosing study in patients with psoriasis, also using daily escalating oral doses of BMS-986251 or placebo. The registry lists BMS-986251 and placebo as the interventions.

The official title identifies safety and tolerability, pharmacokinetics, bioavailability comparison, food effect, pharmacodynamics, and efficacy assessment as study objectives. The posted primary outcome focuses on participant counts for serious adverse events, death, or adverse events leading to study discontinuation. Secondary outcomes include measures of inhibition, including maximum observed inhibition, its timing, time above specified inhibition thresholds, and pre-dose inhibition in Part B.

Details such as the randomization method, allocation ratios, dose-escalation decision rules, masking procedures, and the planned statistical analysis are not reported in the registry record. The record does not explain how the dose levels were selected or how escalation was governed. Although the registry lists conditions beyond psoriasis, the described study parts and arms concern healthy participants and patients with psoriasis. The relationship between the wider condition list and this study’s enrolled participants is 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: 96 participants were enrolled (screened) of whom 36 were screen failures, 22 were approved but not dosed and 38 were randomized in the study.

Only the first 6 of 9 groups are shown.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants who had received at least one dose of BMS-986251 or placebo.

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.

Population: All demographic characteristics for Part A are summarized. Due to early termination of the study, only 1 participant was enrolled in the placebo group and 1 participant in the BMS-986251 group in Part B. Part B demographics data is not reported for privacy reasons.

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants That Experienced the Following: Serious Adverse Events (SAEs), Death or an Adverse Event (AE) Leading to Study Discontinuation, measured over AEs: Day 1 to Day 11 (Part A), Day 1 to Day 24 (Part B); SAEs: Day -21 to within 30 days of discontinuation of dosing (Part A), Day -21 to within 30 days of discontinuation of dosing (Part B).

The primary outcome is the number of participants who experienced serious adverse events, death, or an adverse event leading to study discontinuation. It is expressed as a participant count, and the defined primary-outcome population includes all participants who received at least one dose of BMS-986251 or placebo.

The registry defines an adverse event as a new untoward medical occurrence or worsening of a preexisting medical condition in a participant administered study drug; the event need not be causally related to treatment. A serious adverse event is defined as an untoward medical occurrence that, at any dose, results in death, is life-threatening, or requires inpatient hospitalization. The registry gives separate assessment periods for adverse events and serious adverse events in Parts A and B. It does not give a corresponding primary-outcome timeframe for Part C in the posted description.

Counting participants with events is a straightforward way to describe how many people experienced specified safety outcomes. It does not by itself show how event risk compares between randomized groups, establish causation, or account for differences in exposure duration. The endpoint also combines distinct event categories, and the registry record does not report a single combined result across them. The posted adverse-event figures therefore need to be read as descriptive group counts, not as an adjusted or inferential treatment comparison.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count represent?

The primary outcome is a count of participants who experienced specified events, rather than a continuous measurement or a time-to-event estimate. In general, a count is easiest to interpret alongside the number of participants who could have experienced the event. The registry provides group sizes at risk for the listed safety groups, as well as event counts. These are descriptive observations. They do not, by themselves, estimate a causal treatment effect.

The endpoint definition groups serious adverse events, death, and adverse events leading to study discontinuation. These categories are not interchangeable: they describe different kinds of safety outcomes. A combined endpoint can be useful when the intended question concerns any of several specified outcomes, but interpretation depends on knowing exactly how the combination was constructed and how many participants experienced each component. The registry record does not provide a complete component-level breakdown for the primary endpoint or a combined comparative analysis.

Why do assessment periods matter?

Event counts depend on the period during which events are observed. The registry gives adverse-event windows of Day 1 to Day 11 for Part A and Day 1 to Day 24 for Part B. For serious adverse events, it gives Day -21 to within 30 days of discontinuation of dosing for both Part A and Part B. These differing windows mean that counts should be interpreted in relation to the stated follow-up, rather than as if every group had the same observation period for every event type. The corresponding primary-outcome timeframe for Part C is not reported in the registry record.

General statistical explanation: a rate or time-to-event analysis can incorporate how long participants were observed, whereas a simple count does not necessarily do so. Such approaches require suitable participant-level event and follow-up information. That information and an analysis using it are not reported in the registry record.

What can zero observed events tell us?

A zero count is an observed result, not proof that the underlying event risk is zero. General statistical explanation: uncertainty remains even when no events are observed, and the amount of uncertainty depends in part on how much information was collected. A confidence interval expresses a range of values compatible with the data under a specified statistical model. No confidence intervals for the primary safety counts are reported in the registry record.

General statistical explanation: with small groups, estimates can be imprecise, and a difference in observed counts may reflect chance as well as a true difference in underlying risks. Conversely, matching observed counts do not establish equal risks. The posted information does not include a comparative estimate, a statistical test, or an uncertainty interval that would quantify these possibilities. The descriptive results should therefore not be read as evidence of equivalence or as a definitive comparison of treatment groups.

What does randomization contribute?

Random allocation is intended, in general, to make treatment groups comparable with respect to factors measured and unmeasured at baseline, on average. Masking is intended to limit the influence of treatment knowledge on care, reporting, and assessment. The registry identifies the study as randomized and quadruple-masked, but the method of allocation and the operational details of masking are not reported in the registry record. The designation alone does not show how well these procedures were implemented.

The parallel model means participants are assigned to a study group rather than described as crossing between treatments. The registry record identifies the model as parallel, but does not supply participant-level data or detailed group assignment results for all three parts. Consequently, it is not possible from the posted summary to assess baseline balance, adherence, treatment exposure, or the effects of exclusions.

How should planning illustrations be understood?

General statistical explanation: a sample-size calculation is a planning exercise that estimates how many participants may be needed under stated assumptions. It is not evidence about what the completed study observed, and it is not a substitute for an analysis of trial results. The registry record does not report the study’s own sample-size justification.

The stated planning illustration assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect specified as a fraction of the observed effect. The record says these illustrations are based on the observed effect and are not the trial’s own design. Sample-size values for this primary outcome are not reported in the registry record; the outcome is explicitly not reduced to a single comparison because it has several categories or time points. Any planning illustration should therefore be kept separate from the descriptive safety counts and should not be described as observed power.

General statistical explanation: over-dispersion matters when the variability in count data is greater than a simple model expects; failing to account for it can make uncertainty appear too small. The posted primary endpoint is a count of participants with events, and no over-dispersion analysis is reported. The record also does not identify a specific statistical model for this endpoint. A model should not be inferred from the outcome format alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple objectives and 24 outcome measures, including safety, pharmacokinetic, pharmacodynamic, and efficacy-related measures. When a study evaluates many outcomes, time points, doses, or group comparisons, the chance of obtaining an apparently notable result by chance can increase. General statistical explanation: multiplicity procedures can manage this issue by defining which comparisons are primary and how the interpretation of additional tests will be controlled. The registry record does not report a multiplicity strategy, hierarchy of hypotheses, or adjustment method.

The primary outcome itself covers several event categories, and its assessment periods vary by event type and study part. The record does not report a single combined comparison or explain how separate components would be analyzed. It also does not report inferential analyses for the primary outcome; the registry lists 0 analyses. Thus there is no posted primary-outcome p-value or uncertainty interval to interpret, and no basis for assessing how multiplicity was handled in any analysis.

The registry defines the primary-outcome population as all participants who received at least one dose of BMS-986251 or placebo. This is a dosed population definition. Whether other analysis populations were planned, including an intention-to-treat population, is not reported in the registry record. Neither the handling of participants who discontinued nor the handling of missing outcome data is reported. The registry does not state whether any imputation or sensitivity analyses were planned or conducted.

General statistical explanation: missing-data assumptions can affect estimates when participants have incomplete follow-up, especially when missingness is related to treatment or outcome. A transparent interpretation normally requires information about the amount, timing, and reasons for missingness, together with the analysis approach. Those details are not reported in the registry record. Accordingly, neither the presence nor the impact of missing data can be assessed from the posted summary.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The posted serious-event counts are 0 in every listed group. In Part A, the numbers at risk were 9 for placebo; 6 each for BMS-986251 2 mg, 6 mg, 15 mg, and 30 mg; and 3 for BMS-986251 60 mg. In Part B, 1 participant was at risk in the placebo group and 1 in the 3 mg QD group. The death count was 0 in every listed group as well.

The registry also gives other-event counts for those groups. These range from 0 to 5 in the listed rows, but the category’s definition is not reported in the registry record. The primary outcome mentions adverse events leading to study discontinuation, yet the posted group-level information does not clearly identify these other-event counts as that specific endpoint. They should not be interpreted as such without a stated definition.

These safety observations cover the reported groups in Parts A and B. Adverse-event counts for the psoriasis part are not reported in the registry record. A zero serious-event count in the listed groups describes what was recorded during the stated assessment periods; it does not establish an absence of risk or provide a precise comparison between treatments. The small numbers at risk make that distinction particularly important.

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

The registry record describes a randomized, quadruple-masked study of oral BMS-986251 and placebo in healthy participants and patients with psoriasis. The posted safety group information reports no serious adverse events or deaths in the listed Part A and Part B groups. It also gives counts under an other-event category, whose definition is not reported in the registry record. These are descriptive observations from the groups and periods identified in the record.

The results do not establish that the treatments have equal safety profiles. General statistical explanation: an absence of observed events in a group does not demonstrate that the underlying risk is absent. A comparative conclusion requires an appropriate estimate and a measure of uncertainty, neither of which is reported for the primary endpoint. The posted figures also do not establish whether any recorded other events were caused by treatment; the registry’s own adverse-event definition does not require a causal relationship.

The record does not provide inferential efficacy results for patients with psoriasis, nor does it report the primary safety outcome for Part C in the group information. The official title identifies an efficacy assessment, but an objective in a title is not itself evidence of a result. Likewise, the secondary pharmacokinetic and pharmacodynamic outcomes listed in the record do not establish findings without posted results and analyses.

The study status is terminated, but the reason is not reported in the registry record. The record also does not report the sample-size justification, missing-data approach, multiplicity plan, or detailed statistical analysis for the primary outcome. These limitations prevent a broader conclusion about how the study’s findings should be generalized or compared across groups. The defensible interpretation is confined to the reported design and observed counts, with the absent comparative analyses and unreported study details kept explicit.

13. Why This Trial Matters Statistically

This trial illustrates the difference between an outcome being named in a registry and a result being available for statistical interpretation. The primary endpoint is clearly described as a participant count involving serious adverse events, death, or adverse events leading to discontinuation. However, the posted information does not provide a single comparative estimate for that endpoint or an inferential analysis. Readers therefore need to distinguish the endpoint definition from evidence about differences between randomized groups.

The study also brings together distinct research aims: dose escalation and safety assessment in healthy participants, multiple dosing in patients with psoriasis, pharmacokinetic and pharmacodynamic outcomes, and an efficacy assessment. Each aim can require different summaries and analytic methods. The available registry record lists these purposes and multiple outcome measures, but does not report a comprehensive set of results or an analysis plan. A list of objectives alone cannot show whether each question was answered.

The small numbers at risk in the posted Part B groups and the absence of serious events make uncertainty central to interpretation. General statistical explanation: sparse-event data can be highly imprecise, so observed counts should not be mistaken for exact estimates of underlying risk. Without a comparative estimate and uncertainty interval, the record cannot quantify the strength or precision of a treatment contrast.

Finally, the terminated status and the absence of a reported reason highlight the importance of complete reporting. The record gives study timing and status, but not the rationale for termination or the relationship between termination and the planned objectives. This example underscores a practical statistical lesson: design labels, endpoint definitions, and descriptive counts each contribute useful information, but none can substitute for reported analyses, transparent handling of missing data, and clear explanations of how planned questions were addressed.

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 posted safety groups cover Part A and only two listed groups in Part B. Although the registry describes a psoriasis dosing part, the corresponding adverse-event group counts are not reported in the registry record. The available counts therefore cannot characterize safety across all described study parts.

The primary endpoint includes several categories, but the registry does not give a complete component breakdown or a combined comparative result. The meaning of the other-event counts is also not defined in the posted record. Although the primary outcome refers to adverse events leading to study discontinuation, the available counts cannot be assumed to represent that specific category.

The group sizes at risk are small, and no confidence intervals, p-values, or adjusted comparisons are reported for the primary endpoint. Consequently, the precision of the event counts and the extent of any between-group differences cannot be quantified from the record. Participant-level data, exposure time, and detailed follow-up information are not reported, limiting assessment of event rates and observation time.

The registry identifies randomization, quadruple masking, and a parallel model, but does not report the randomization procedure, allocation ratios, masking implementation, or protocol deviations. The analysis plan, sample-size justification, missing-data methods, multiplicity handling, and any sensitivity analyses are not reported in the registry record. The reason the study was terminated is also not reported. These omissions constrain interpretation of the safety observations and prevent a full appraisal of the study’s planned and completed analyses.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of Experimental Medication BMS-986251, Taken by Mouth, in Healthy Participants and Patients With Average to Very Serious Psoriasis — NCT03329885.
• Registry record last updated 2019-10-21; status last verified 2019-09.
• Results first posted 2019-10-21.
• 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

NCT03329885 is a randomized, quadruple-masked, parallel Phase 1 and Phase 2 study of oral BMS-986251 and placebo. Enrollment was 38. The registry lists healthy-participant single- and multiple-ascending-dose parts and a multiple-dosing part in patients with psoriasis. The study began on 2017-11-02, had a primary completion date of 2018-06-26, and is listed as terminated; the reason is not reported in the registry record.

The primary outcome counts participants with serious adverse events, death, or adverse events leading to study discontinuation. In the listed Part A and Part B groups, the serious adverse-event and death counts were 0. The registry lists 24 outcome measures and 0 analyses. It does not report a comparative primary-outcome analysis, the study’s sample-size justification, or a reason for termination. The posted safety counts are descriptive and do not establish comparative effects or efficacy.