Effect of Fosaprepitant on Motor Evoked and Somatosensory Evoked Potentials Under General Anesthesia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Fosaprepitant on Motor Evoked and Somatosensory Evoked Potentials Under General Anesthesia (NCT03197064), a na phase 4 study. The primary outcome is Somatosensory Evoked Potentials (SEPs), Extremity Amplitude (Left Upper Extremity).

2. Clinical Question

3. Trial Design

The registry record describes a completed phase 4 study with a single-group model and an enrollment of 11. It lists fosaprepitant 150 mg as the drug intervention. The planned comparison is not between separately assigned treatment groups: allocation is recorded as not applicable, and the record lists no masking. The study dates are January 1, 2018, for the start and January 31, 2020, for primary completion.

The study’s stated purpose was to assess whether intravenous fosaprepitant could interfere with nervous-system monitoring signals in patients having surgery under general anesthesia. The primary outcome concerns somatosensory evoked potential amplitude in the left upper extremity, measured at baseline before dosing and at 30, 60, and 90 minutes after dosing. A pre-dose reading can describe a participant’s measurement before the intervention, while post-dose readings describe measurements at the stated later times. This arrangement permits observation of measurements over time within the treated group, but does not supply a concurrent untreated group for comparison.

The registry record lists five outcome measures and 15 analyses. It does not report the full analysis plan, the specific model used for repeated measurements, or how the listed analyses correspond to the outcome measures. The record also does not report a sample-size justification. Any planning illustrations associated with the posted results are not the trial’s own design rationale; their stated assumptions use equal allocation between two arms, whereas the registered study is single-group. Such illustrations are not observed power and should not be read as evidence about the precision or power of this study.

The record marks the study completed, but completion status alone does not provide outcome findings. Numerical summaries for the primary endpoint, including means and standard deviations at the specified time points, are not reported in the registry record. The absence of those results limits interpretation of the study’s central question.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Somatosensory Evoked Potentials (SEPs), Extremity Amplitude (Left Upper Extremity), measured over Baseline (pre-dose) and 30, 60, and 90 minutes post-dose.

The primary endpoint is the mean amplitude, in µV, of somatosensory evoked potentials recorded from the left upper extremity. The registry record specifies a mean with standard deviation as the summary format and lists baseline before dosing and 30, 60, and 90 minutes after dosing as the measurement times.

Somatosensory evoked potentials are electrical signals produced by the nervous system in response to somatosensory stimulation. The registry description says they are typically elicited through electrical stimulation of the median nerve and read from the skull using electroencephalography. In this study, the signals were recorded using a 4-channel EEG system. Such measurements are used for neuromonitoring during surgical procedures that may affect sensory components of the central or peripheral nervous system.

Amplitude describes the size of the recorded response. Tracking it before and after drug administration is relevant to the study’s stated question about whether fosaprepitant could affect the monitoring signal. A change in a measured signal would need to be interpreted in the context of the recording method, timing, anesthesia, and other study details; the registry record does not provide enough information to evaluate those influences. It also does not report the endpoint’s numerical results, so the observed amplitude levels and their variability cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpreting a clinical study requires separating the design, the measurements, the statistical summaries, and the conclusions those summaries can support. In this study, the registry record describes one treated group and repeated measurements of a continuous signal. It does not provide numerical primary-outcome results or a detailed statistical analysis plan. The concepts below are general explanations of how such data are commonly understood; they should not be mistaken for methods confirmed in the registry record.

What does a mean describe?

A mean is the arithmetic average of recorded values. For a continuous endpoint such as evoked-potential amplitude, it offers a compact description of the group’s average signal at a particular measurement time. A mean can be useful for comparing measurements across times, but it does not show the full distribution of individual values. Participants may have values that differ considerably from the average, and the average may shift because of a small number of observations. The registry specifies mean and standard deviation as the primary outcome’s summary format, but does not report the actual means or standard deviations.

What does a standard deviation describe?

A standard deviation describes how dispersed observations are around their mean. Greater dispersion means the individual measurements are less clustered around the average. It is not the same as the uncertainty in the estimated mean: uncertainty also depends on how many observations contribute and on the data structure. Because the record does not report the endpoint summaries or the number analyzed at each time point, the spread and precision of the primary outcome cannot be judged from the posted results.

How are repeated measurements different from separate groups?

Measurements from the same participant are generally related. A person with a relatively high measurement at baseline may also tend to have relatively high measurements later. General statistical methods for repeated measurements account for this within-participant relationship rather than treating every measurement as if it came from a different person. The choice of method depends on the data, assumptions, and analysis plan. The registry record does not report which model, if any, was used to analyze the repeated measurements.

A within-participant comparison can describe how measured values changed after dosing in the enrolled group. It does not by itself separate an intervention effect from changes that might have occurred over time for other reasons. A concurrent control group can help with that separation by providing a comparison under the same general study conditions. This study is listed as single-group and has no like-for-like control comparison.

Why does variability matter?

Signal measurements can vary among participants and across recordings. General statistical reasoning distinguishes a change in the group average from the variation of individual readings. If variability is substantial relative to a change, the estimate may be uncertain. When observations are more variable than a statistical model assumes, that is called over-dispersion; ignoring it can make uncertainty look smaller than it is. The registry record does not provide enough numerical outcome information to assess variability or over-dispersion in this study, and it does not report a model whose assumptions could be reviewed.

What would a confidence interval add?

In general, a confidence interval gives a range of values compatible with the data and a stated statistical procedure. It communicates uncertainty around an estimate, rather than only presenting a single point estimate. A narrow interval indicates greater precision under the method’s assumptions; a wide interval indicates less precision. A confidence interval does not by itself establish causation or clinical importance. No confidence interval for the primary outcome is reported in the registry record, so precision cannot be evaluated from the posted results.

What do significance tests and p-values mean?

In general, a significance test assesses how compatible observed data are with a specified null hypothesis under the test’s assumptions. A p-value is not the probability that the null hypothesis is true, nor does it measure the size or importance of an effect. Its interpretation depends on the hypothesis, analysis method, and whether the test was planned or selected after examining data. The registry record does not report a primary endpoint p-value, the statistical test used, or the hypothesis tested.

The record counts five outcome measures and 15 analyses. A count of analyses does not reveal which comparisons were made or how results were selected for emphasis. With multiple outcomes or tests, the chance of at least one seemingly unusual result can increase; general approaches may adjust the testing threshold or distinguish confirmatory from exploratory analyses. Whether such an approach was used is not reported in the registry record.

What can planning calculations tell readers?

Sample-size calculations are planning tools that estimate how many observations may be needed for a chosen effect size, variability assumption, significance level, and desired power. They are not a measure of the power actually achieved after a study has ended. The planning illustrations described for this record use a two-arm, equal-allocation assumption and are not the study’s own design rationale. They should not be interpreted as observed power for this single-group study. The registry record does not report a sample-size justification for the enrolled group.

For this study, the central statistical limitation is not a particular choice between models, because the analysis method is not reported. It is that the numerical endpoint findings and sufficient analysis details are absent from the registry record. Without those details, estimates, uncertainty, assumptions, and the handling of repeated measurements cannot be independently assessed.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists five outcome measures and 15 analyses. Those counts indicate that several measurements or analyses were registered, but do not explain which analyses were planned for each outcome, which comparisons were confirmatory, or whether any were exploratory. A method for controlling multiplicity, such as adjusting for multiple statistical tests or setting a hierarchy among outcomes, is not reported in the registry record. Without that information, a reader cannot determine how the possibility of chance findings across multiple analyses was handled.

Numerical results for the primary outcome are not reported in the registry record. The record also does not state whether outcome data were missing, how many participants contributed data at each measurement time, or how any missing measurements were handled. It does not identify an analysis population, such as all enrolled participants or a subset with complete measurements. Enrollment of 11 should therefore not be assumed to mean that 11 participants were included in every analysis.

For repeated measurements, missingness can matter because participants may have data at some time points but not others. General statistical methods make different assumptions about why data are missing and can produce different estimates. The record does not report a missing-data strategy or enough information to assess those assumptions. These omissions limit evaluation of the analysis and its uncertainty; they do not establish that data were missing or that any particular analysis was inappropriate.

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.

For the fosaprepitant group, the registry record lists 11 participants at risk for serious adverse events and 0 affected. It also lists 11 at risk for other adverse events and 0 affected, with 0 deaths. No top serious adverse-event terms are listed. These are the safety counts reported in the registry record.

A count of zero means that no events in that category were recorded among the participants counted in the posted results. It does not demonstrate that the risk of an event is absent. The group is small, and there is no separate control group in the listed design to provide a concurrent safety comparison. The record does not describe event definitions, the period of safety follow-up, ascertainment procedures, or whether all enrolled participants contributed to each safety count. Those details are not reported in the registry record.

Serious adverse events and other adverse events are separate categories in the posted counts. A zero count in one category should not be taken as a statement about every possible symptom or event, or as proof of safety beyond the observations recorded. The reported figures describe the registry’s event counts; they do not support a comparative estimate of risk.

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

The study addresses a practical measurement question: whether a drug administered during surgery under general anesthesia might be associated with changes in a nervous-system monitoring signal. Its primary endpoint is left upper-extremity somatosensory evoked potential amplitude, measured before dosing and at three stated post-dose times. The topic is statistically relevant because a drug-related change in a monitoring measure could complicate interpretation of that measure. The registry record establishes that this question was studied, but it does not provide the numerical primary outcome results needed to say what the measurements showed.

The result does not establish whether amplitude increased, decreased, or remained similar after dosing. Means, standard deviations, estimated changes, confidence intervals, and test results are not reported in the registry record. Consequently, neither the magnitude of any observed change nor its precision can be described. The study’s completion status does not fill this reporting gap.

The design also limits what can be inferred causally. Since the record lists a single treated group and no concurrent control group, any before-and-after pattern would be an observation over time within that group, not a randomized estimate of the drug’s effect relative to no drug. Surgery, anesthesia, timing, and measurement conditions could also be relevant to changes. The registry record does not report enough detail to disentangle these influences.

The safety counts record no serious adverse events, other adverse events, or deaths in the listed group. Those counts are descriptive and do not establish that no risk exists, particularly without a comparison group and fuller information about safety follow-up and event ascertainment.

Overall, the registry supports a description of the study question, its single-group design, its primary measurement schedule, and the posted safety counts. It does not support a conclusion about the observed primary endpoint or a causal claim about fosaprepitant’s effect on monitoring signals. Those conclusions would require outcome data and analysis details not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically interesting because it concerns a measurement used to monitor nervous-system function during surgery, rather than a conventional comparison of clinical outcomes between treatment groups. The endpoint is a continuous electrical signal, and the measurement is repeated in participants over time. Such a design raises important questions about within-person variability, measurement conditions, and the analysis of correlated observations.

The registry record makes a useful distinction between a pre-dose reference and a concurrent control group. Baseline measurements can help describe participants before treatment and can support within-group descriptions of later values. They do not provide the same evidence as measurements from a separate group observed under comparable conditions without the intervention. This matters when readers consider whether a time pattern can be attributed to the drug rather than to other changes during surgery or anesthesia.

The record also illustrates why complete numerical reporting is essential. Naming the primary endpoint and its timing makes the question understandable, but means, standard deviations, estimates of change, and uncertainty are needed to evaluate the observed signal. The listed enrollment and analysis counts cannot substitute for these results. Nor can a completed study status indicate whether the measurements changed or how precisely any change was estimated.

Finally, multiple registered outcomes and analyses make transparency about the analysis plan relevant. Without knowing which comparisons were prespecified or how multiplicity was handled, readers cannot fully assess the risk of selective emphasis across analyses. These are general statistical issues, not conclusions that a particular analysis was or was not conducted. The study therefore matters as an example of how design, measurement, and transparent outcome reporting jointly determine what can be learned from a clinical study.

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 main trial-specific limitation is the single-group design. All participants are listed in the fosaprepitant group, with no concurrent control group. The baseline measurement provides a before-dose reference but cannot control for other changes over time or establish what the signal would have been without fosaprepitant. The registry record lists masking as none, so it does not describe a blinded measurement or treatment process.

The enrollment was 11. The registry record does not report the number of participants with complete primary outcome measurements at each time point, or the number included in each analysis. It is therefore not possible to determine whether all enrolled participants contributed to the primary endpoint summaries. The record does not report numerical means or standard deviations, so the observed variability and precision also cannot be assessed.

The primary endpoint concerns the left upper extremity. Although the registry lists other outcome measures, their detailed results are not included in the record details. Conclusions about the primary measurement should not be extended to other limbs, monitoring modalities, or outcomes without corresponding results. Measurement was listed at baseline and at 30, 60, and 90 minutes after dosing; longer-term measurements are not reported for this endpoint.

The registry record does not report the statistical model, analysis population, missing-data handling, multiplicity procedure, or sample-size justification. It also does not provide sufficient procedural detail to assess how operation-related or anesthesia-related factors were handled. These limitations restrict evaluation of the methods and results, rather than proving that any specific source of bias occurred.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effect of Fosaprepitant on Motor Evoked and Somatosensory Evoked Potentials Under General Anesthesia — NCT03197064.
• Registry record last updated 2022-07-18; status last verified 2022-07.
• Results first posted 2022-07-18.
• 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

NCT03197064 is a completed phase 4, single-group study of fosaprepitant 150 mg administered intravenously under general anesthesia. The registry record lists an enrollment of 11 and no separate control group. Its primary outcome is the mean left upper-extremity somatosensory evoked potential amplitude, in µV, measured before dosing and at 30, 60, and 90 minutes afterward.

The study’s stated purpose was to determine whether fosaprepitant could interfere with nervous-system monitoring signals. The registry lists five outcome measures and 15 analyses. Numerical results for the primary endpoint and details of the statistical analysis are not reported in the registry record. The safety counts list 0 serious adverse events, 0 other adverse events, and 0 deaths among 11 participants at risk. The design and available results support a description of the study question and recorded counts, but not a causal estimate of the drug’s effect on the monitoring signal.