This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for The Role of Orexin in Human Panic Disorder (NCT02593682), a randomized phase 4 study. The primary outcome is Change in Orexin Levels (Blood) +1 Minute.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02593682 |
| Phase | Phase 4 |
| Condition | Panic Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Francisco |
| Results posted | Yes |
2. Clinical Question
Population
People with panic disorder were the intended population. The registry lists an enrollment of 3, but does not report how many participants were assigned to each group or which participants contributed to the primary outcome. The primary outcome description states that the principal investigator left the institution and that efforts to locate the data were exhausted. That statement limits what can be learned from the registry about the people actually assessed.
Intervention
The suvorexant group was to receive 10 mg suvorexant 2 hours before a one-minute 35% CO2 challenge. The study purpose describes investigating whether suvorexant affects orexin levels and whether it is associated with reduced panic symptoms in response to the challenge. Those are questions the study set out to examine, not findings established by the available record.
Comparator
The comparator was placebo, compounded to look identical to the study drug, given 2 hours before the same one-minute 35% CO2 challenge. The registry describes randomized allocation and quadruple masking. It does not identify which people were masked or report whether masking was assessed during the study.
Primary question
The primary outcome asks how blood orexin levels changed from baseline to +1 minute after the CO2 challenge. The central comparison would concern the change associated with suvorexant relative to placebo. However, the registry record contains no numerical outcome result or analysis for this endpoint. The primary question therefore remains unanswered by the posted results; the study aim should not be mistaken for evidence about the direction or size of an effect.
3. Trial Design
The registry describes a Phase 4 randomized, quadruple-masked, parallel study comparing suvorexant with placebo in people with panic disorder. It lists the study status as completed and the enrollment as 3. The study start is recorded as 2016-05, and primary completion as 2020-03-13. The sponsor is the University of California, San Francisco. These details describe the registered study; they do not establish how many participants completed the challenge or contributed usable outcome data.
The suvorexant arm description specifies 10 mg given 2 hours before a one-minute 35% CO2 challenge. The placebo was compounded to look identical to the study drug and was given at the same stated interval before the same challenge. The registry’s parallel-model description indicates distinct groups rather than a crossover description. It does not report the allocation ratio, arm-specific enrollment, the randomization procedure, or whether the intended timing and challenge procedures were followed for each participant.
Random allocation is generally intended to reduce systematic differences between groups at assignment. Masking is generally intended to limit the influence of treatment knowledge on care, measurement, or assessment. Those are general purposes, not confirmation that these protections operated as intended in this study. “Quadruple” is the registry’s masking label; which roles it covers and how masking was maintained are not reported in the registry record.
The study purpose identifies two interests: whether suvorexant affects orexin levels and whether it is associated with decreased panic symptoms in response to the challenge. The registered primary outcome concerns blood orexin change. The record lists 4 outcome measures, but the other outcome definitions and their results are not reported in the registry record. It lists no analysis entries. The endpoint description also says the principal investigator left the institution and efforts to locate data were exhausted. As a result, the design can be described, but the available record does not support a reconstruction of the analysis actually performed or of the participant flow through the study.
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
| Stage | Suvorexant Group | Placebo Group |
|---|---|---|
| STARTED | 0 | 0 |
| COMPLETED | 0 | 0 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: PI left institution and all efforts to locate data have been exhausted.
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: PI left institution and all efforts to locate data have been exhausted.
| Characteristic | Unit | Suvorexant Group | Placebo Group | Total |
|---|---|---|---|---|
| Participants analysed | 0 | 0 | 0 | |
| Age, Categorical: <=18 years | — | — | — | |
| Age, Categorical: Between 18 and 65 years | — | — | — | |
| Age, Categorical: >=65 years | — | — | — | |
| Sex: Female, Male: Female | — | — | — | |
| Sex: Female, Male: Male | — | — | — | |
| Race (NIH/OMB): American Indian or Alaska Native | — | — | — | |
| Race (NIH/OMB): Asian | — | — | — | |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | — | — | — | |
| Race (NIH/OMB): Black or African American | — | — | — | |
| Race (NIH/OMB): White | — | — | — | |
| Race (NIH/OMB): More than one race | — | — | — | |
| Race (NIH/OMB): Unknown or Not Reported | — | — | — | |
| Region of Enrollment: United States | participants | — | — | — |
6. Primary Endpoint
The registry lists the primary outcome as Change in Orexin Levels (Blood) +1 Minute, measured over Baseline and +1 minute post-CO2 challenge.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in blood orexin levels from baseline to +1 minute after the CO2 challenge. It is a biological measurement aligned with the study’s stated question about whether suvorexant affects orexin levels in people with panic disorder. The challenge provides the context for the post-baseline measurement; the registry does not report the laboratory assay, measurement units, or the exact calculation used to define change.
In general, measuring change from baseline focuses attention on how a participant’s value differs across the specified measurement times. A comparison between randomized groups could then address whether those changes differ between the suvorexant and placebo groups. That interpretation depends on having valid measurements and a clearly specified analysis. It cannot be made from the endpoint label alone.
The registry gives the timeframe as baseline and +1 minute post-CO2 challenge, and describes the endpoint as change from baseline to +1 minute. It does not report an observed change, a between-group estimate, a measure of uncertainty, or a statistical test. The unit and statistical parameter are also not reported in the registry record. The primary outcome description says the principal investigator left the institution and efforts to locate the data were exhausted. Thus the endpoint is defined at a broad level, but its numerical result and the details needed to interpret its scale are unavailable.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record gives the study question and design but no numerical result for the primary outcome. There is no posted estimate of blood orexin change, no comparison between the randomized groups, and no confidence interval or test result. Consequently, the magnitude, direction, and precision of any group difference cannot be evaluated from the registry record. The study’s purpose statement is not a result: asking whether suvorexant affects orexin levels or is associated with fewer panic symptoms does not show that either occurred.
Enrollment is listed as 3. That figure describes the registered enrollment, not necessarily the number with usable primary-outcome data. The record does not report participant counts by arm, missing measurements, or the analysis population. The endpoint note explains that the principal investigator left the institution and that efforts to locate the data were exhausted. This is an important reason the primary result is unavailable, but it does not reveal what values were collected or what they would have shown.
The registry lists 4 outcome measures and 0 analyses. It does not report the other outcome definitions or their results in the registry entries. No inferential claim about panic symptoms, orexin, or a treatment-group contrast can therefore be made from numerical outcome evidence in this record. The absence of a posted estimate is not evidence that the groups were identical, nor is it evidence of a difference. It means the result cannot be assessed.
In general, a point estimate describes the observed contrast, while an uncertainty interval conveys how imprecisely that contrast is estimated under the analysis assumptions. Neither is available. Even if a small study produced an estimate, a broad interval could leave substantial uncertainty; that general possibility should not be confused with a finding about this study. No such interval is reported.
The adverse-event records list zero serious events, zero other events, and zero deaths for each group, while also listing zero participants at risk in each group. Those entries cannot be read as evidence that no enrolled participant experienced an event: the risk counts do not establish an event-monitoring denominator. The registry record does not provide event information that permits an informative safety comparison. Overall, the posted material supports a description of the planned comparison and the data-availability problem, not a conclusion about treatment effects.
9. Statistical Methods Explained
What does randomization contribute?
In general, randomization assigns participants to study groups using a chance-based procedure. Its statistical purpose is to make group assignment less dependent on participant characteristics, which can reduce systematic selection differences. It does not guarantee that groups will be alike in every respect, particularly in a very small study, and it cannot correct problems that arise after assignment, such as unavailable outcome measurements. The registry identifies the study as randomized, but the randomization sequence, allocation concealment, and allocation ratio are not reported in the registry record. The enrollment of 3 is not an arm-specific count, so the group sizes cannot be inferred.
What does masking mean for interpretation?
In general, masking can reduce the chance that knowledge of assigned treatment influences participant expectations, study conduct, outcome assessment, or analysis. The registry labels the study quadruple-masked and says the placebo was compounded to look identical to the study drug. The record does not specify the roles covered by the masking label, how treatment assignments were protected, or whether masking remained intact. The design label is relevant context, but it does not by itself verify that masking prevented bias.
How would a group comparison be interpreted?
In general, a treatment comparison for a change endpoint would compare the changes observed in the randomized groups, or use an analysis that estimates a group contrast while accounting for baseline values. The appropriate approach depends on the prespecified estimand, measurement properties, and analysis plan. The registry record does not report the statistical parameter, model, or analysis plan for this endpoint. It also does not give endpoint values, so no group contrast can be interpreted or recalculated.
A confidence interval is, in general, a range of values compatible with the data under a specified statistical procedure and its assumptions. Its width reflects precision: wider intervals indicate more uncertainty about the size of the estimated contrast. A confidence interval is not reported for the primary outcome. A p-value, when used, summarizes how incompatible the observed data are with a specified null model; it does not measure the probability that a treatment effect is real or its clinical importance. No primary-outcome p-value or other test result is reported.
What are the sample-size assumptions?
The planning illustration is described as a calculation based on the observed effect, not as the study’s own design justification. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the groups, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. These are assumptions for an illustration, not evidence about the study’s original planning. The actual sample-size justification is not reported in the registry record.
In general, a sample-size calculation asks how much information would be needed to detect a specified effect under chosen assumptions. Such an estimate depends on the effect size and variability, along with the testing approach and allocation assumptions. A calculation based on an observed effect is especially dependent on that effect estimate, which may itself be uncertain. It is not a measure of the probability that this completed study detected an effect. The registry record does not supply the numerical inputs or planning results needed to assess the illustration, and it does not report an original justification. Any planning illustration should therefore be read as a conditional planning exercise, not as observed power or a trial finding.
What can be inferred from missing analysis information?
The registry lists no analysis entries for the outcomes. It does not report whether the primary comparison was intended to use a particular model, how missing measurements would be handled, or whether any adjustment for multiple outcomes was planned. These omissions matter because analysis choices can affect the estimate and its uncertainty. General statistical principles can explain those choices, but cannot identify which choices were made in this study.
For a small study, estimates are generally sensitive to each participant’s observations, and uncertainty may be substantial. That is a general methodological concern, not a calculated precision statement for this study. With no outcome values, no arm counts, and no analysis result, neither the scale of uncertainty nor the robustness of a result can be determined. The absence of a posted analysis should be distinguished from a null result: no test result is available to interpret.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 4 outcome measures, but only the primary outcome is described in the registry entries. The other outcome definitions, their designated status, and their results are not reported in the registry record. It is therefore not possible to determine how many inferential comparisons were planned or reported, or whether a strategy for controlling multiplicity was used. Multiplicity arises in general when several hypotheses are tested: the more opportunities to declare a result, the greater the chance of at least one apparently unusual result under a collection of null hypotheses. Whether and how that concern applied to the analyses cannot be established.
There are 0 analysis entries. The registry does not specify the planned analysis population, whether participants were to be analyzed according to randomized assignment, or how protocol deviations would be addressed. These are not interchangeable details. In general, an analysis population defines which participants contribute to an estimate, and different definitions can yield different results. The record does not permit identification of the population used for any analysis.
Missing-data procedures are not reported in the registry record. The primary outcome description states that the principal investigator left the institution and that efforts to locate data were exhausted. This explains why the primary outcome is unavailable in the registry, but it does not describe whether participant measurements were missing, whether data were collected but lost, or whether any statistical handling of missing values was attempted. No missingness rate or sensitivity analysis is reported. Without those details or outcome data, the potential effect of missingness on a treatment comparison cannot be evaluated.
In general, multiplicity control and missing-data methods should be interpreted alongside the planned estimand and analysis population. Here, those methodological details are not available, so no claim about their adequacy or consequences is warranted.
11. What the Result Does, and Does Not, Mean
The registry establishes that a randomized comparison of suvorexant and placebo was registered for people with panic disorder, with both groups scheduled to receive their assigned preparation before a one-minute 35% CO2 challenge. It also establishes that the primary endpoint concerned blood orexin change from baseline to +1 minute after the challenge. These registry entries define the research question and its setting; they do not answer it.
The primary outcome’s numerical result is not reported in the registry record. No effect estimate, uncertainty interval, or statistical test is available, and the record identifies the loss of access to the principal investigator and exhausted efforts to locate the data. The available information therefore does not show whether the groups differed in orexin change, in which direction any difference might have gone, or how precisely it could be estimated. The study purpose also mentions panic symptoms, but the registry entries contain no numerical result for that question.
The enrollment figure of 3 should not be interpreted as the number with complete measurements or as the number in either arm. Arm-specific counts and the analysis population are not reported. Likewise, the adverse-event entries list zero participants at risk, so the zero event entries do not establish a meaningful absence of events among participants.
In general, a missing result is distinct from a result showing no difference. It is also distinct from evidence of benefit or harm. The registry record permits neither a positive nor a negative conclusion about the study’s treatment comparison. It documents a completed study and an unavailable primary result, leaving the central empirical question unresolved in the posted record.
12. Why This Trial Matters Statistically
This study is statistically notable because the registry describes a randomized comparison but does not provide the primary outcome result. Randomization can support a fair comparison when assignment and follow-up are implemented appropriately, but it cannot substitute for outcome data. Without the orexin measurements or a reported analysis, the design cannot yield an assessable estimate of the contrast.
The enrollment of 3 also makes transparency about participant flow and uncertainty especially important. In general, small studies can produce estimates that depend heavily on the observations of individual participants. That general consideration does not establish the precision of this study’s estimate, because no estimate or group counts are available. It does underscore why readers need the observed data summary, an uncertainty measure, and clear information about who was analyzed.
The record also distinguishes an original trial design from a planning illustration based on an observed effect. These answer different questions. A design justification explains how the planned study size was selected; a calculation based on an observed effect describes hypothetical planning under stated assumptions. Neither can recover an unavailable trial result. The original justification is not reported in the registry record, and no numerical planning result is included in the registry entries.
Finally, the record highlights the value of reporting outcome definitions, analysis populations, missing-data decisions, and all outcome results. Without them, readers cannot assess multiplicity, precision, or the relation between the stated study aims and the analyses. The main statistical lesson is not a claim about suvorexant, but the limits imposed when a registered primary endpoint has no accessible result.
13. 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 most consequential limitation is that the primary outcome result is unavailable. The registry says the principal investigator left the institution and efforts to locate the data were exhausted. No orexin values, group contrast, uncertainty interval, or test result are reported, so the intended primary comparison cannot be evaluated.
Enrollment is listed as 3, but arm-specific counts, participant flow, and the number with usable measurements are not reported in the registry record. It is therefore unclear from the available information how many participants contributed to each endpoint. The endpoint’s unit, assay details, and statistical parameter are also not reported, limiting interpretation even apart from the missing result.
The record lists 4 outcome measures but does not identify the other outcomes in the registry entries. It lists no analyses and does not report the analysis population, statistical model, missing-data approach, or any multiplicity strategy. The original sample-size justification is not reported in the registry record. The stated planning illustration is based on an observed effect and specified assumptions, but the registry entries do not include numerical inputs or results that would permit an assessment of it.
The adverse-event records show zero participants at risk in both groups alongside zero recorded events and deaths. Those entries do not provide a usable participant denominator for interpreting event occurrence. More broadly, a completed status does not establish that complete outcome data or a complete analysis are available. These limitations concern what can be learned from the registry record; they do not establish what happened to participants or what the unreported study results would have been.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: The Role of Orexin in Human Panic Disorder — NCT02593682.
- Registry record last updated 2021-07-02; status last verified 2021-06.
- Results first posted 2021-07-02.
- 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.
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17. Record Summary
NCT02593682 is a Phase 4 randomized, quadruple-masked, parallel study sponsored by the University of California, San Francisco. The condition is panic disorder; enrollment is listed as 3, and status is completed. The recorded start is 2016-05 and primary completion is 2020-03-13.
The study compared 10 mg suvorexant with placebo before a one-minute 35% CO2 challenge. The primary endpoint was change in blood orexin from baseline to +1 minute post-challenge. The registry lists 4 outcome measures and 0 analyses. The primary outcome description states that the principal investigator left the institution and efforts to locate the data were exhausted. Consequently, the primary result is not reported in the registry record. The available information describes the study question and design but does not support an estimate of the treatment-group difference.