Relative Bioavailability of Evobrutinib Tablet Batches: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Relative Bioavailability of Evobrutinib Tablet Batches (NCT07214922), a randomized phase 1 study. The primary outcome is Area Under the Plasma Concentration-time Curve From Time Zero Extrapolated to Infinity (AUC0-inf) of Evobrutinib.

2. Clinical Question

The study asks whether pharmacokinetic exposure differs among manufacturing batches of the evobrutinib tablet formulation when administered under fasted conditions to healthy participants. Its stated purpose also includes assessing safety and tolerability. The registry identifies the study as Phase I, open-label, randomized and crossover, with 28 participants enrolled.

Each participant was assigned to a treatment sequence involving all four treatments. The posted results give geometric mean AUC0-inf values and geometric coefficients of variation by treatment, but do not report estimated pairwise differences or ratios for this primary endpoint. The record therefore describes the exposure values by treatment without providing a direct statistical estimate of how far one batch differs from another.

3. Trial Design

This was a Phase I, open-label, randomized crossover study of evobrutinib tablet manufacturing batches in healthy participants. The registry reports enrollment of 28 participants and a completed status. The recorded study start was 2023-01-18, and primary completion was 2023-02-24. The sponsor is Merck Healthcare KGaA, Darmstadt, Germany, an affiliate of Merck KGaA, Darmstadt, Germany.

The four treatment sequences were ABCD, BDAC, CADB and DCBA. In each sequence, participants were scheduled to receive a single oral dose of each of Treatments A, B, C and D across four periods on Days 1, 3, 5 and 7, under fasted conditions. Randomizing the order of treatments can help separate treatment differences from effects associated with receiving treatments in a particular order. That is a general design rationale; the registry does not report the details of the randomization procedure or how sequence assignments were balanced.

In a crossover design, participants receive more than one treatment, so comparisons can use information from the same participant across treatment periods. This can reduce the influence of stable differences between participants when the analysis appropriately accounts for the repeated measurements. The registry does not report the statistical model used for the primary analysis, whether period or sequence effects were included, or how any carryover concerns were handled. The arm-level summaries alone do not establish how within-participant information was used.

The study was open-label, meaning masking was not used according to the registry. The record describes single-dose administration and pharmacokinetic sampling from pre-dose through 24 hours post-dose on the treatment days. Details of any washout arrangements, sample-size justification, or protocol deviations are not reported in the registry record. The completed status indicates the study is recorded as completed; it does not by itself supply information about adherence, exclusions, or the completeness of data.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Pharmacokinetic (PK) Analysis Set was a subset of the Safety Analysis Set and included all participants who receive at least one dose of active investigational medicinal product (IMP) and provide at least one measurable post-dose concentration.

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 Area Under the Plasma Concentration-time Curve From Time Zero Extrapolated to Infinity (AUC0-inf) of Evobrutinib, measured over Pre-dose, 0.25, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16 and 24 hours post-dose on Days 1, 3, 5 and 7.

The primary endpoint is AUC0-inf for evobrutinib, reported in hour×nanogram per milliliter (h×ng/mL). AUC describes the area under a concentration-time profile and is used as a measure of total plasma exposure. Extending the area to infinity incorporates an estimate of the part of the concentration curve after the final relevant measured concentration, rather than limiting exposure to the observed sampling window.

The registry says AUC0-inf was calculated by combining AUC0-t and AUCextra. AUCextra was calculated using Clast pred/Lambda z: Clast pred is the calculated concentration at the last sampling time where measured concentration was at or above the lower limit of quantification, and Lambda z is the apparent terminal rate constant estimated by log-linear regression of concentrations in the terminal log-linear phase. Thus, the reported endpoint includes both measured-data information and a model-based extrapolation.

Pharmacokinetic exposure is relevant to comparing formulations or manufacturing batches because differences in the concentration-time profile can be reflected in the area under that profile. The registry reports geometric means and geometric coefficients of variation for each treatment. It does not report a primary between-treatment estimate, confidence interval, or formal decision criterion, so the arm-level AUC values describe the observed summaries but do not quantify the uncertainty in a batch-to-batch contrast.

The primary pharmacokinetic analysis set was a subset of the Safety Analysis Set. It included participants who received at least one dose of active investigational medicinal product and provided at least one measurable post-dose concentration. The number of participants contributing to each reported treatment summary varies in the posted results; reasons for differences from the 28 enrolled participants are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is summarized using geometric means and geometric coefficients of variation. In general, a geometric mean is useful for measurements that are positive and may be analyzed on a logarithmic scale, as is often the case for pharmacokinetic exposure. It describes a central value on the original scale after averaging on a log scale. A geometric coefficient of variation describes relative spread on a multiplicative scale; it is not the same quantity as a standard deviation. The registry does not report the exact primary analysis model or the details of any transformation used in its inferential analysis.

What does AUC0-inf include?

AUC0-inf combines the observed portion of the concentration-time profile with an extrapolated terminal portion. The posted definition states that the terminal contribution is based on the predicted concentration at the final sampling time with a measured concentration at or above the lower limit of quantification, divided by the apparent terminal rate constant. The rate constant is estimated through log-linear regression of concentrations from the terminal log-linear phase. This means the endpoint is not simply a sum of measured concentrations: its estimate also depends on the selected terminal phase and the extrapolation procedure. The registry does not report how much of each participant's AUC0-inf was extrapolated or what criteria were used to determine the terminal phase.

How should a crossover design be understood?

In general, a crossover design gives each participant more than one treatment, allowing treatment responses to be compared within the same participant. Such comparisons can be more informative than comparisons of unrelated groups when stable participant characteristics influence the outcome. The design also makes treatment order and period relevant: responses may vary by time or be influenced by earlier treatment. The registry lists randomized sequences and four treatment periods, but does not report whether the primary model included period, sequence, or participant effects, or how potential carryover was assessed. It is therefore not possible to infer those analysis choices from the design label alone.

What do the arm summaries establish?

The reported geometric means and coefficients of variation are descriptive summaries for each treatment. To estimate a relative treatment effect, an analysis would ordinarily report a contrast, often on a scale appropriate to the endpoint, together with an interval expressing uncertainty. A confidence interval generally gives a range of values compatible with the data and the assumptions of the analysis; it conveys precision as well as direction. No primary AUC contrast or confidence interval is reported in the registry record. Consequently, the primary summaries do not give the precision of a treatment-to-treatment comparison.

The posted secondary heart-rate analysis uses means and standard deviations for changes from baseline. The comparison results include mean differences, intervals and unadjusted p-values. In general, a mean difference is the estimated difference between the two group means as defined by the comparison, while a confidence interval describes uncertainty around that estimate. A p-value evaluates compatibility of the data with a specified null hypothesis under the analysis assumptions; an unadjusted p-value does not account for examining multiple outcomes or comparisons. The record does not state a multiplicity plan.

What do the sample-size illustrations mean?

The planning illustrations are based on the observed secondary heart-rate effect, not on the study's own design assumptions. They use a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, and consider planning for 100%, 75% or 50% of the observed effect. These are hypothetical planning calculations. They are not evidence of the study's actual planned sample size, and they are not observed power. The registry does not report the trial's sample-size justification. A planning exercise derived from an observed estimate can be especially sensitive to the uncertainty in that estimate; it should not be interpreted as proof that a future study of a particular size would achieve its target.

Why does variability matter?

In general, greater variability makes it harder to estimate a treatment contrast precisely from a fixed amount of information. The geometric coefficients of variation describe variability in the primary exposure summaries, while the secondary heart-rate results report standard deviations. Those statistics use different scales and should not be compared as though they were interchangeable. In a crossover study, within-participant variation and correlations across periods can also affect precision. The registry does not report the within-participant variance or correlation used in any primary comparison, and no primary comparison is posted from which to assess its precision.

The result counts are analysis-specific. The primary analysis set requires at least one dose and at least one measurable post-dose concentration; the safety summaries report treatment-specific numbers at risk. In general, analysis populations define which participants contribute to a given result and can affect interpretation when observations are missing. The registry does not report the reasons for treatment-specific count differences, the handling of missing pharmacokinetic measurements, or sensitivity analyses for missing data.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and multiple secondary outcomes, but a statistical plan for handling multiple comparisons is not reported in the registry record. It is therefore unclear whether the primary comparisons were intended to form a single family of tests, whether secondary outcomes were exploratory, or whether any hierarchy or adjustment was prespecified. Without that information, unadjusted secondary p-values should not be treated as if they controlled the overall false-positive risk across all endpoints and contrasts.

Missing-data methods are also not reported in the registry record. The primary analysis population is defined as a subset of the Safety Analysis Set that received at least one dose and provided at least one measurable post-dose concentration. That definition identifies who can enter the PK analysis set, but it does not explain how missing sampling times, unmeasurable concentrations, incomplete treatment periods, or missing endpoint values were handled. Reasons for the different treatment-specific analysis counts are not reported.

The record does not report whether analyses were conducted according to randomized sequence, whether any participants were excluded after randomization, or whether sensitivity analyses assessed the effect of exclusions or missingness. These omissions matter because missing pharmacokinetic observations can affect both the amount of information available and the representativeness of the analyzed participants. In a crossover design, missing one period can also affect the availability of within-participant comparisons.

The registry does not report interim analyses or stopping rules. It also does not report a sample-size justification for the trial, or the model and decision criteria for the primary endpoint. These points should be regarded as unreported rather than assumed to have been absent from the conduct of the study. The posted record does not provide enough information to determine the planned inferential framework or how it was implemented.

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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: seizure (3.7%).

The safety results are reported as counts of participants with events in each treatment group. For serious adverse events, the record lists 0 of 26 for Treatment A, 0 of 27 for Treatment B, 1 of 27 for Treatment C and 0 of 27 for Treatment D. The listed serious adverse-event term is Seizure, reported as 3.7%. No deaths are reported for any treatment group.

These are descriptive counts from the groups at risk, not comparative risk estimates. The record does not report a statistical comparison of serious adverse events between treatments or establish that an event was caused by a particular treatment. Small counts provide limited information about the range of possible event rates, so absence of a recorded event in a group does not establish that no such risk exists.

For other adverse events, the record lists 2 participants for Treatment A, 1 for Treatment B, 1 for Treatment C and 5 for Treatment D. These figures should be interpreted alongside the corresponding numbers at risk and the registry's definitions of treatment-emergent events. The record does not provide event-level timing, duration, relatedness assessments, or a fuller narrative in the registry record; those details are not reported in the registry record.

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

The posted results show that geometric mean AUC0-inf values were reported for all four treatments, with corresponding geometric coefficients of variation and treatment-specific analysis counts. This establishes that the registry contains descriptive pharmacokinetic summaries for the treatments. It does not establish the size or precision of a primary between-treatment effect, because no pairwise AUC estimates or confidence intervals are reported.

The pattern of arm-level means should not be read as a formal ranking of batches or as evidence that treatments are equivalent. A difference between descriptive means can reflect a treatment effect, sampling variability, or features of the analysis and study conduct. A proper comparative interpretation requires an estimate of the contrast and its uncertainty, along with the analysis assumptions and prespecified decision criteria. Those elements are not reported for the primary endpoint in the registry record.

The randomized crossover design is appropriate in general for comparing multiple treatments within participants, but the design label alone does not show how the data were analyzed or how incomplete periods were handled. The record describes treatment sequences and the PK analysis-set definition, yet does not report the primary statistical model, missing-data strategy or a treatment comparison. This limits what can be concluded from the posted summaries.

The secondary heart-rate results and safety counts add descriptive information but cannot substitute for primary exposure comparisons. Unadjusted secondary tests are also less persuasive as confirmatory evidence when the multiplicity plan is not reported. Similarly, the serious adverse-event counts describe what was recorded among participants at risk but do not establish causation or comparative safety.

Overall, the registry supports a description of the study design and its posted outcome summaries. It does not provide enough inferential detail to conclude whether the tablet manufacturing batches have equivalent exposure, how precisely their exposures differ, or whether any observed safety pattern is attributable to treatment. Those conclusions should not be inferred from group summaries alone.

13. Why This Trial Matters Statistically

This study is statistically interesting because its crossover design addresses a common challenge in pharmacokinetic comparisons: participant-to-participant variability. In general, observing multiple treatments in the same participants can make within-participant contrasts informative, because each participant can serve as a comparison for their own responses. That potential advantage depends on complete and interpretable measurements and on an analysis that accounts for the repeated observations.

The endpoint also illustrates how pharmacokinetic summaries can depend on more than the directly observed concentrations. AUC0-inf includes an extrapolated terminal component based on a predicted final concentration and an estimated terminal rate constant. The resulting summary is a meaningful exposure measure, but its interpretation depends on how the terminal phase is identified and modeled. The registry describes the calculation but does not report the contribution of extrapolation or primary analysis details.

A key statistical distinction is between descriptive values and comparative inference. The registry reports geometric means by treatment, but not primary contrast estimates or their uncertainty. Without those, it is not possible to assess the precision of the apparent differences or evaluate any equivalence criterion. This distinction is central in studies comparing formulations or manufacturing batches: similar-looking summaries are not, by themselves, evidence of equivalence.

The record also highlights why prespecified analysis details matter. The secondary results include unadjusted comparisons, while a multiplicity strategy is not reported. Sample-size illustrations use an observed secondary effect and are explicitly planning calculations rather than the study's own design justification. These details help separate a descriptive result, a hypothesis test and a hypothetical planning exercise, which answer different statistical questions.

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.

A central limitation of the posted record is that the primary endpoint is presented through treatment-level geometric means and variability, without pairwise AUC0-inf estimates, confidence intervals or p-values. The summaries therefore do not quantify the uncertainty of the relative exposure comparisons that motivate the study. No equivalence or bioequivalence margins, or other primary decision criteria, are reported in the registry record.

The treatment labels A through D are used in the results, while the study description refers to manufacturing batches and a reference batch. The record identifies Treatment A as the analysis control, but the mapping from each treatment label to a specific batch or reference formulation is not reported. This makes the batch-level interpretation less direct.

Although the study is described as randomized and crossover, the primary statistical model is not reported. Details of the randomization method, sequence allocation, period effects, carryover assessment, treatment of incomplete sequences, and any within-participant covariance assumptions are not reported in the registry record. The treatment-specific analysis counts also differ, without reported reasons.

The endpoint uses an extrapolated terminal component, but the fraction of AUC0-inf that was extrapolated and the criteria for selecting the terminal log-linear phase are not reported. Missing-data handling, sensitivity analyses and sample-size justification are also not reported. The study was open-label; the registry does not describe any measures used to limit bias in assessments. Finally, the study enrolled healthy participants, and the posted record does not establish how these findings generalize beyond the study population.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Relative Bioavailability of Evobrutinib Tablet Batches — NCT07214922.
• Registry record last updated 2025-12-23; status last verified 2025-12.
• Results first posted 2025-12-23.
• 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

The registry record describes a completed, Phase I, open-label, randomized crossover study of relative bioavailability across four evobrutinib tablet manufacturing treatments in healthy participants. Enrollment was 28. Participants were assigned to one of four sequences and scheduled to receive single oral doses under fasted conditions across four treatment periods.

The primary endpoint was AUC0-inf, summarized by geometric mean and geometric coefficient of variation for each treatment. The posted record does not include primary pairwise comparisons or confidence intervals. Secondary outcomes include adverse events, vital signs and electrocardiogram measures; the record also reports secondary heart-rate comparisons. Safety results include one serious adverse event in the Treatment C group and no reported deaths.

The registry does not report the primary statistical model, multiplicity strategy, missing-data approach, or sample-size justification. The posted summaries support descriptive reading of the recorded outcomes, but do not establish a precise comparative effect or equivalence among the manufacturing batches.