A Study in Healthy Men to Test How Different Doses of BI 474121 Are Taken up and How They Influence the Amount of a Molecular Messenger (cGMP) in the Spinal Fluid: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study in Healthy Men to Test How Different Doses of BI 474121 Are Taken up and How They Influence the Amount of a Molecular Messenger (cGMP) in the Spinal Fluid (NCT04672954), a randomized phase 1 study. The primary outcome is Maximum Exposure-related Change From Baseline (Calculated as Ratio) of Cyclic Guanosine Monophosphate (cGMP) in Cerebrospinal Fluid (CSF).

2. Clinical Question

3. Trial Design

This was a phase 1 study of different single oral doses of BI 474121 in healthy male subjects. The registry lists 24 participants enrolled and identifies the overall study as randomized, single-blind, and parallel. The treatment arms were placebo and BI 474121 at 2.5 mg, 10 mg, 20 mg, and 40 mg.

The arm descriptions show that the study was organized in parts with differing design features. Part 1 was randomized, placebo-controlled, and single-blind; it included placebo and the 20 mg dose. Part 2 was non-randomized and open-label and included the 40 mg dose. Part 3 was randomized and open-label and included the 2.5 mg and 10 mg doses. Thus, the overall design labels do not describe every part’s allocation and masking in the same way. The registry record does not report further details about how participants were assigned within each part.

All interventions are described as single oral doses. The arm descriptions specify uncoated tablets taken with 240 milliliter of water after fasting overnight for at least 10 hours. Those details describe the recorded administration conditions; they do not establish that all other study conditions were identical across parts.

The study started on 2021-01-07, reached primary completion on 2021-07-01, and is listed as completed. Its objectives were pharmacokinetic and pharmacodynamic: to assess CSF cGMP, compare CSF exposure with plasma exposure, and explore exposure-effect relationships across doses. The record lists seven outcome measures and four analyses for the primary endpoint. The protocol’s planned sample-size rationale, allocation details beyond the arm descriptions, and any interim-analysis plan are 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: All subjects were screened for eligibility prior to participation in the trial. Subjects attended a specialist site which ensured that they (the subjects) strictly met all inclusion and none of the exclusion criteria. Subjects were not to be allocated to a treatment group if any of the entry criteria were violated.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Pharmacodynamic parameter analysis set (PDS): all evaluable subjects who were entered and treated with one dose of study drug and who provided at least one evaluable pre- and post-dose measure for a pharmacodynamic endpoint.

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: Treated set (TS): all subjects who were entered and treated with one dose of study drug (i.e. verum or placebo).

6. Primary Endpoint

The registry lists the primary outcome as Maximum Exposure-related Change From Baseline (Calculated as Ratio) of Cyclic Guanosine Monophosphate (cGMP) in Cerebrospinal Fluid (CSF), measured over Within approximately 2, 1, and 0.17 hours before and 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14 and 24 hours following drug administration..

The primary endpoint is the maximum exposure-related change from baseline in cyclic guanosine monophosphate (cGMP) in cerebrospinal fluid (CSF), expressed as a ratio. The ratio is maximum cGMP divided by baseline cGMP. It is intended to capture the largest cGMP value in a defined window associated with drug exposure, relative to that subject’s pre-dose level.

For BI 474121-treated subjects, the registry defines the maximum cGMP value as the measurement within 1 hour before and 4 hours after the CSF maximum measured drug concentration, or Cmax. For placebo subjects, the window is anchored to the median BI 474121 time to maximum concentration, or tmax, in CSF. Baseline is the arithmetic mean of that subject’s pre-dose cGMP measurements above the lower limit of quantification.

A ratio makes a relative change interpretable across differing baseline levels: a ratio of 1 represents no change relative to baseline, while values on either side represent relative increases or decreases. This is a general explanation of ratio endpoints; the registry’s posted results do not include arm-level endpoint values. The endpoint was analyzed on a logarithmic scale using ANCOVA, as described in the record. The registry also reports that the endpoint’s summary parameter is a geometric mean with standard error, but no arm-level estimates or standard errors are posted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary endpoint analysis as analysis of covariance (ANCOVA) on the logarithmic scale. ANCOVA compares groups while accounting for covariates specified in the model. The specific covariates, model formula, and diagnostic procedures are not reported in the registry record. Because the endpoint is a ratio and analysis is on the logarithmic scale, the reported results are expressed as ratio contrasts rather than absolute changes in cGMP concentration.

What does a ratio estimate express?

A ratio compares quantities multiplicatively. The registry reports a ratio estimate for each dose against placebo, with estimates of 1.29 for 2.5 mg, 1.66 for 10 mg, 1.14 for 20 mg, and 1.75 for 40 mg. On the ratio scale, 1 is the reference representing no relative difference. An estimate above 1 indicates that the numerator of the reported contrast is larger than its denominator, but the registry record does not spell out the contrast’s numerator and denominator convention. For that reason, the ratios are best reported as posted rather than translated into a direction of treatment effect.

How should the confidence intervals be read?

A confidence interval gives a range of values compatible with the data and the statistical model at the stated confidence level. It communicates precision as well as the estimate’s uncertainty. The registry reports 90% confidence intervals: 0.78 to 2.13 for 2.5 mg, 0.99 to 2.79 for 10 mg, 0.71 to 1.85 for 20 mg, and 1.06 to 2.89 for 40 mg. The intervals vary in their bounds, and each spans a range of possible ratio contrasts rather than pinpointing a single value. The 40 mg interval excludes the ratio reference value of 1, while the other reported intervals include it. This description does not by itself establish a clinical interpretation.

What do the p-values add?

A p-value describes how unusual data at least as incompatible with a null hypothesis would be under that hypothesis and the model assumptions. The posted values are 0.394, 0.109, 0.631, and 0.069 for the 2.5 mg, 10 mg, 20 mg, and 40 mg comparisons, respectively. A p-value is not an effect size, a probability that the treatment works, or a measure of the probability that the null hypothesis is true. It also does not communicate precision as directly as an interval. The record does not state how these p-values were adjusted, if at all, for the multiple dose comparisons.

Why does the endpoint use a time window?

Drug concentration changes over time after dosing, and the endpoint is defined around CSF Cmax. For treated subjects, the cGMP maximum is selected within 1 hour before and 4 hours after that concentration maximum. For placebo, the window is tied to the median BI 474121 tmax in CSF. This timing rule connects the pharmacodynamic measurement to the exposure profile rather than taking an arbitrary single measurement. It also means that endpoint construction depends on the specified timing and on evaluable measurements. The registry does not report further details about missing or below-quantification measurements beyond its baseline definition.

What is the analysis population?

The primary analysis population is described as the pharmacodynamic parameter analysis set: evaluable subjects who were entered and treated with one dose of study drug and who provided at least one evaluable pre-dose and post-dose measurement for a pharmacodynamic endpoint. This is not necessarily identical to everyone enrolled or everyone assigned to an arm. The record does not give a single total for this analysis set or explain the disposition of participants who were not evaluable.

Arm-level endpoint values are absent in the posted results: the record lists the group sizes but no corresponding value, spread, or interval for those entries. The analysis comparisons are nevertheless reported. No simple recalculation from arm-level summary statistics is available for this endpoint in the registry record, so the ANCOVA results are the usable numerical comparisons. General statistical principle: adjusted model comparisons and unadjusted calculations from summaries need not coincide, because they can use different information and assumptions. In this case, no such recalculation is posted to compare with the model estimates.

The sample-size assumptions described for planning illustrations are not a record of the trial’s design justification. The registry record does not report the protocol’s sample-size calculation, target power, or the assumptions used to choose the enrolled number. A planning illustration based on an observed effect would be a hypothetical design exercise, not observed power and not evidence about the precision actually achieved in this study.

10. Analyses Reported by the Sponsor

The posted ANCOVA comparisons are the registry’s reported analyses for the primary endpoint. They compare placebo with each listed BI 474121 dose and report ratio estimates, 90% confidence intervals, and p-values. The registry does not provide arm-level primary endpoint values or spreads, so an unadjusted recalculation from those summaries is not available. There is therefore no recalculated estimate to set against the sponsor’s ANCOVA results.

The reported comparisons are 1.29 for 2.5 mg, 1.66 for 10 mg, 1.14 for 20 mg, and 1.75 for 40 mg. Their associated intervals and p-values remain the appropriate figures to describe the posted analysis; they should not be replaced by an invented estimate or by a calculation from missing arm-level data. The registry record does not report the ANCOVA covariates, its full model specification, or enough detail to reproduce the analysis independently.

There is no reported discrepancy between sponsor analyses and a recalculation in the registry record. That absence should not be mistaken for independent validation: the lack of underlying summary values prevents the comparison. General statistical principle: when a sponsor’s prespecified analysis and a simple unadjusted recalculation differ, the sponsor’s own analysis is generally the primary result for interpreting its planned model, while the recalculation can provide a separate descriptive check. Here, only the posted ANCOVA results are numerically available.

11. Multiplicity, Missing Data and Analysis Populations

The record reports four primary-endpoint ANCOVA comparisons, one for each BI 474121 dose versus placebo. It does not report whether the comparisons were treated as a family for inference, whether any multiplicity adjustment was used, or which comparison was designated as the principal one. Without that information, the reported p-values should be read as posted values rather than as a documented multiplicity-controlled set. The registry also does not report whether the primary endpoint was selected from a larger set of planned endpoints after results were examined.

The trial lists seven outcome measures and five posted secondary outcomes. Those include plasma and CSF maximum measured concentrations, time to maximum measured concentrations, and maximum exposure-related CSF cGMP concentration. The registry record does not provide a complete hierarchy of endpoint testing, a prespecified testing sequence, or a familywise error strategy. The presence of multiple doses and outcomes makes such information relevant, but the record does not allow a judgment about how multiplicity was handled.

The primary endpoint population is the pharmacodynamic parameter analysis set, comprising treated and evaluable subjects with at least one pre-dose and post-dose pharmacodynamic measurement. This definition makes evaluability part of inclusion in the analysis. The number meeting the definition in each arm, reasons for missing measurements, and handling of missing values are not reported in the registry record. Nor does the record describe sensitivity analyses for missing data, imputation, or the influence of measurements below the lower limit of quantification.

The baseline definition uses the arithmetic mean of pre-dose measurements above the lower limit of quantification. The primary outcome is a maximum selected from a specified time window. These rules are stated, but the record does not explain how a participant with insufficient measurements in that window was handled or whether timing deviations occurred. Those omissions limit assessment of how robust the result is to missingness and endpoint construction.

The record does not report a statistical analysis plan, interim analyses, a sample-size justification, or a detailed account of analysis-population deviations. These are information gaps, not evidence that a particular procedure was or was not performed.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The adverse-event figures distinguish serious adverse events from other adverse events. For the serious-event counts, the record lists zero affected participants in each group: placebo, 2.5 mg, 10 mg, 20 mg, and 40 mg. The corresponding numbers at risk are 4, 4, 4, 6, and 6. The record also lists zero deaths in every group. These are the posted serious-event counts for the recorded groups and should be read as observed counts in this study, not as proof that serious events cannot occur.

The other-adverse-event figures list all participants at risk as affected: 4 in placebo, 4 at 2.5 mg, 4 at 10 mg, 6 at 20 mg, and 6 at 40 mg. The record does not provide the event terms or severity breakdown for these other events in the registry record for this analysis. The 40 mg primary-endpoint group size is listed as 5, while its adverse-event number at risk is 6. This indicates that the posted analysis and safety counts do not use identical denominators; the record does not explain the difference.

Small group counts and the limited study size mean the safety figures describe what was recorded among these participants, not the full range or frequency of possible adverse events in a larger population. The registry record does not report further detail on event timing, exposure duration, or attribution beyond the counts summarized in the adverse-event record.

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

The results describe the registry’s primary pharmacodynamic comparisons of CSF cGMP ratios between placebo and four single doses of BI 474121. The posted ratio estimates range from 1.14 for 20 mg to 1.75 for 40 mg, with 90% confidence intervals that are broad. One interval excludes the ratio reference value of 1; the other three include it. The p-values range from 0.069 to 0.631. These values describe the reported statistical comparisons, not a direct measure of clinical benefit or harm.

The endpoint is a laboratory measure of cGMP in CSF, selected in relation to drug concentration timing. The study also set out to assess drug exposure in CSF relative to plasma and to explore exposure-effect relationships across doses. The primary endpoint comparisons alone do not answer every pharmacokinetic or pharmacodynamic objective. Although the registry lists secondary outcomes, the registry entries do not include their numerical results.

These results do not establish a clinical effect in patients. The enrolled population consisted of healthy men, and the study evaluated single doses. No patient population, longer-term outcomes, or clinical endpoint results are reported in the registry record. It would be inappropriate to translate the biomarker ratios into a claim about health benefit or treatment effectiveness.

The study’s design also qualifies the dose comparisons: the parts differed in randomization and masking, and the 40 mg group was studied in a non-randomized, open-label part. The registry does not give enough detail to determine how those design differences were addressed analytically. In addition, the lack of arm-level primary endpoint summaries prevents an independent descriptive check of the reported model comparisons.

In general, a statistical result is best understood by considering its estimate, uncertainty, analysis population, design, and endpoint relevance together. Here, the reported estimates and intervals provide a numerical account of the posted ANCOVA results, while missing model details, analysis-set counts, and secondary-outcome results leave important context unavailable.

14. Why This Trial Matters Statistically

This trial is statistically interesting because it links pharmacokinetics and pharmacodynamics in a central-fluid setting. Its stated objectives include measuring BI 474121 exposure in CSF relative to plasma, assessing CSF cGMP, and exploring exposure-effect relationships across oral doses. The primary endpoint’s time window is anchored to drug concentration timing, so the analysis concerns a biomarker response in relation to exposure rather than a single fixed-time measurement.

The registry also illustrates why a trial’s overall design labels may not tell the whole story. Although the overall study is described as randomized, single-blind, and parallel, the arm descriptions identify randomized single-blind, randomized open-label, and non-randomized open-label parts. Those differences matter when considering whether dose comparisons share the same design context.

The reported comparisons are accompanied by 90% confidence intervals, making uncertainty visible rather than relying on p-values alone. At the same time, no arm-level endpoint values are posted, and the model’s covariates and full specification are not reported. The numerical estimates can therefore be described, but their independent reproducibility and the details of adjustment cannot be assessed from the registry record.

Finally, this record separates what was planned as an objective from what is numerically available. It lists multiple pharmacokinetic and pharmacodynamic outcomes, yet the primary endpoint comparisons are the only numerical results included in the registry record for this analysis. Recognizing that distinction helps prevent conclusions about unreported outcomes or about broader clinical effects from being inferred from a biomarker analysis in healthy men.

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 primary endpoint results are not accompanied by arm-level values or measures of spread. This prevents direct comparison of the groups’ reported endpoint summaries and makes an unadjusted recalculation unavailable. The registry reports the ANCOVA ratios and intervals, but not the covariates, model formula, diagnostic checks, or other details needed to reproduce the analysis.

The design differs across study parts. Placebo and 20 mg were in the randomized, placebo-controlled, single-blind part; 2.5 mg and 10 mg were in a randomized, open-label part; and 40 mg was in a non-randomized, open-label part. The registry does not explain whether or how these part-level differences were incorporated into analysis. They complicate interpretation of dose comparisons as if all groups arose under one common design.

The analysis population is defined by treatment and availability of evaluable pre-dose and post-dose pharmacodynamic measurements, but the record does not report its total or arm-specific counts. Reasons for missing measurements, methods for handling missing data, and sensitivity analyses are also not reported. The adverse-event record gives a different number at risk for the 40 mg group than the primary-endpoint group listing; the registry does not explain this difference.

The record does not report multiplicity procedures, a sample-size justification, interim analyses, or a detailed statistical analysis plan. It also does not include numerical results for the listed secondary outcomes in the registry record. These gaps constrain assessment of precision, analysis choices, and the full set of study objectives. The healthy male population and single-dose setting further limit how far these biomarker findings can be generalized beyond the studied context.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study in Healthy Men to Test How Different Doses of BI 474121 Are Taken up and How They Influence the Amount of a Molecular Messenger (cGMP) in the Spinal Fluid — NCT04672954.
• Registry record last updated 2024-03-08; status last verified 2023-07.
• Results first posted 2024-03-08.
• 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

NCT04672954 is a completed phase 1 study of single oral doses of BI 474121 in healthy male subjects. The registry reports enrollment of 24 and study dates from 2021-01-07 to primary completion on 2021-07-01. The intervention groups were placebo and 2.5 mg, 10 mg, 20 mg, and 40 mg BI 474121, with design features varying across study parts.

The primary endpoint was the maximum exposure-related change from baseline in CSF cGMP, expressed as a ratio. Four placebo comparisons were reported using ANCOVA on the logarithmic scale, with ratio estimates, 90% confidence intervals, and p-values. Arm-level primary endpoint values, analysis-set totals, detailed model specifications, and multiplicity procedures are not reported in the registry record. The safety record lists zero serious adverse events and zero deaths in each group.