GB001 in Adult Participants With Chronic Rhinosinusitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for GB001 in Adult Participants With Chronic Rhinosinusitis (NCT03956862), a randomized phase 2 study. The primary outcome is Change From Baseline to Week 16 in Sino-Nasal Outcome Test (SNOT) 22 Total Score.

2. Clinical Question

The trial also evaluated safety, pharmacokinetics and pharmacodynamics. Its secondary outcomes covered imaging, nasal polyp scores, nasal congestion and other symptoms, smell identification, time to response, exacerbations, and treatment-emergent adverse events. These outcomes broaden the clinical questions but do not replace the prespecified role of the primary endpoint.

The primary result is a comparison of average score changes, not a count of participants who improved. The reported contrast was a mean difference between treatment groups, with an interval estimate and a p-value. Those statistics describe the estimated group-level contrast and its uncertainty; they do not establish how any individual participant experienced treatment.

3. Trial Design

This was a Phase 2a, randomized, double-blind, placebo-controlled, multicenter study with a parallel-group design. The registry lists an enrollment of 97 and a completed status. The study began on 2019-05-16, and its primary completion date is 2020-07-09. The registry describes 16 weeks of treatment.

Participants were assigned to GB001 or placebo. The GB001 regimen was 40 mg once per day, and placebo was given once per day. Double blinding means that the study is described as masking participants and study personnel, although further details about who remained masked are not reported in the registry record. Randomization is intended, in general, to make treatment groups comparable on average at the start of a study; the registry record does not provide additional details about the sequence-generation or allocation-concealment procedures.

The primary endpoint was change from baseline to Week 16 in SNOT-22 total score. The registry describes its primary analysis population as participants who were randomized, received at least 1 dose, and had a baseline and a post-baseline value. The arm counts reported for this endpoint are 49 for placebo and 45 for GB001. The safety summaries use different at-risk counts, so those populations should not be assumed to be identical to the primary endpoint population.

Secondary outcomes included both continuous measures and time-to-event measures. The record lists changes in Lund-Mackay, Nasal Polyp, nasal congestion, total symptom, and smell identification scores, along with time to first nasal polyp response and time to first chronic rhinosinusitis exacerbation. It also lists the percentage of participants with a treatment-emergent adverse event. Specific details of randomization strata, site-level procedures, and the full 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: The study included a run-in period, during which eligibility for randomization was determined. 192 participants entered the run-in period, 97 of whom were randomized.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent-to-treat (ITT) population: all participants who were randomized and received at least 1 dose of study treatment. Participants with a baseline and a post-baseline value.

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 Change From Baseline to Week 16 in Sino-Nasal Outcome Test (SNOT) 22 Total Score, measured over Baseline, Week 16.

The primary endpoint is change from baseline to Week 16 in the Sino-Nasal Outcome Test (SNOT) 22 total score. SNOT-22 is a validated questionnaire intended to assess the impact of chronic rhinosinusitis on quality of life. It has 22 items, uses a 5-point category scale, and asks about symptoms over a 2-week recall period. Its total score ranges from 0 to 110, with higher scores indicating greater impact of chronic rhinosinusitis on quality of life.

A change score compares each participant’s Week 16 score with their baseline score. The registry reports least-squares mean changes for each treatment group and a mean difference between the groups. A negative change indicates a lower score at follow-up than at baseline; given the score interpretation, that direction corresponds to a lower reported impact. The group comparison, rather than either group’s change alone, addresses the randomized treatment contrast.

In general, patient-reported outcome measures can capture aspects of daily experience that may not be represented by imaging or examination findings alone. A validated questionnaire can make those experiences measurable in a standardized way, although responses remain subject to recall and reporting variation. The registry does not report a threshold for interpreting a change as clinically important, so the size of the observed score change should not be assigned a clinical-importance label from these results alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is continuous: each participant has a SNOT-22 score, and the outcome is the change in that score from baseline to Week 16. The registry reports least-squares means and a mean difference. These are model-based summaries designed to compare groups within the stated analysis, rather than unadjusted summaries reconstructed from individual participant records.

What does a least-squares mean represent?

In general, a least-squares mean is an estimate of a group mean from a statistical model. It can account for variables included in that model and express the group result on a common model-based basis. The precise interpretation depends on the model and the covariates it includes. The registry names a mixed models analysis but does not report the full model specification, so it is not possible to state which covariates or repeated-measure structure were used.

The primary results give least-squares mean changes of -18.1 for placebo and -18.3 for GB001. The reported mean difference is -0.2. The contrast is the statistic that compares the groups; neither group’s individual change alone answers the comparative question. The record also reports a 95% confidence interval from -7.6 to 7.1 for the difference. Because this range includes zero and values on either side, the estimate is compatible with no mean difference as well as with contrasts in either direction.

How should the confidence interval and p-value be read?

In general, a confidence interval conveys both the estimated effect and its precision under the statistical model. A narrower interval indicates greater precision, while a wider interval indicates greater uncertainty. It is not a measure of the range of individual participant outcomes. The interval is for the between-group mean difference, not for the change in an individual participant.

The reported p-value is 0.950. In general, a p-value measures how unusual the observed result, or a more extreme result, would be under a specified null model and its assumptions. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The registry classifies the comparison as a superiority analysis. A non-small p-value does not demonstrate equivalence; equivalence requires a prespecified margin and an analysis designed to test whether effects fall within that margin. Such a margin is not reported in the registry record.

What does a mixed models analysis contribute?

In general, mixed models can analyze outcomes measured over time while representing correlations among repeated measurements from the same participant. They can also estimate group differences while accounting for model terms such as treatment, time, and their interaction, depending on the chosen specification. Their validity depends on the model being appropriate and on assumptions about the data, including how missing observations relate to observed information. The registry record does not report enough detail to verify these assumptions or reproduce the fitted model.

The primary analysis population is described as randomized participants who received at least 1 dose and had both a baseline and a post-baseline value. This definition identifies who was included for the primary endpoint as recorded, but it does not reveal the number or pattern of missing observations, how missing values were handled, or whether any sensitivity analyses were conducted. Those details are not reported in the registry record.

How are the time-to-event results analyzed?

For time to first response in Nasal Polyp Score and time to first chronic rhinosinusitis exacerbation, the registry reports Cox regression hazard ratios. In general, a hazard ratio compares the instantaneous event rates between groups over follow-up, conditional on the model. It is not a ratio of event counts or a difference in median times. A hazard ratio of 1 represents equal hazards under the model; confidence intervals that include 1 do not rule out no difference. The proportional-hazards assumption and any covariate adjustments are not reported in the registry record.

The time-to-response analysis also reports median times and confidence limits. A median time is the point by which half of the relevant event-time distribution has experienced the event, subject to the analysis and censoring. In general, incomplete follow-up can leave some event-time quantities not estimable. The registry does not report a median time for the exacerbation outcome, and details of censoring and event definitions beyond the outcome names are not reported in the registry record.

What do the planning illustrations mean?

In general, sample-size calculations describe planning requirements under stated assumptions; they are not a measure of the probability that a completed trial detected an effect. The registry’s planning illustrations use the observed effect or stated fractions of it, a two-sided significance level of 0.05, equal allocation, and a normal approximation. For time-to-event outcomes, they express requirements as total events using the Schoenfeld approach; other illustrations express participants per arm. These are planning illustrations, not observed power, and they do not establish that the study was designed around those calculations. The trial’s own sample-size justification is not reported in the registry record.

10. Analyses Reported by the Sponsor

The registry reports the primary comparison using a mixed models analysis. It gives a mean difference of -0.2, a 95% confidence interval from -7.6 to 7.1, and p = 0.950. Those are the sponsor’s reported analysis results in the registry record. The posted arm-level least-squares mean changes are -18.1 for placebo and -18.3 for GB001.

A simple recalculation from posted summary statistics, when available, is unadjusted and may not reproduce a model-based analysis. In this record, no discrepancy is flagged between the reported analysis and the posted summary results. The reported mixed models analysis remains the primary inferential result because it is the analysis recorded for the trial; a summary-statistic recalculation would not replace the study analysis or account for model features that are not available in the registry.

The interval estimate is broad enough to include zero and contrasts in either direction. The p-value does not provide evidence against the no-difference value under the reported analysis, but it is not evidence that the groups are equivalent. The registry record does not report the model specification or a prespecified equivalence margin, so stronger conclusions than the reported superiority comparison supports are not warranted.

11. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is identified, but the registry record does not report a multiplicity-control strategy for the several secondary outcomes. In general, testing multiple outcomes increases the chance that at least one result will appear statistically notable by chance, even if there is no corresponding effect. Methods such as a hierarchy of tests or an adjustment to significance thresholds can address this issue, but the record does not indicate that either approach was used. Secondary p-values should therefore not be treated as confirmatory unless an appropriate plan is documented.

The record describes the primary analysis population as randomized participants who received at least 1 dose and had a baseline and a post-baseline value. This is the population definition available for interpreting the reported primary endpoint. It differs in description from the safety summaries, which report at-risk counts of 50 for placebo and 47 for GB001. The registry does not explain the differences between endpoint-specific populations, so counts from one analysis should not be substituted for those in another.

Missing-data methods are not reported in the registry record. The record does not state how missing Week 16 measurements were handled, whether participants with incomplete follow-up were included in model-based estimates, or whether sensitivity analyses evaluated alternative assumptions. In general, missing-data assumptions matter because the observed outcomes among participants with available measurements may not represent outcomes among those without measurements. Without the analysis details, the extent to which missingness could affect the estimates cannot be assessed.

Interim analyses, stopping rules, and the detailed statistical analysis plan are not reported in the registry record. The trial’s sample-size justification is also not reported. The planning illustrations based on observed effects are not evidence of the study’s original design assumptions or observed power. These omissions limit assessment of prespecification and analytic flexibility, but they do not change the numerical result of the primary analysis recorded in the registry.

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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: endometriosis (2.1%).

The registry reports serious adverse events among 50 participants at risk in the placebo group and 47 participants at risk in the GB001 group. There were 0 serious adverse events in the placebo group and 1 in the GB001 group. The registry reports 0 deaths in each group. These are descriptive counts for the recorded safety population and should not be interpreted as a precise estimate of comparative risk.

Other adverse events are reported for 10 participants at risk in the placebo group and 12 in the GB001 group. These figures are separate from the serious adverse event counts. The registry lists Endometriosis at 2.1% among the top serious adverse-event terms, but does not identify an arm for that term in the recorded information. The registry record does not provide enough detail to interpret the event’s clinical course or relationship to treatment.

In general, uncommon events are difficult to compare reliably in a study of this size, and a small difference in counts does not by itself establish a treatment-related safety difference. The record’s summary does not provide event-level detail or an adjusted comparative safety analysis. These figures describe what was reported in the registry; they do not establish that either treatment is safe or unsafe.

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

The primary endpoint result is an estimated mean difference of -0.2 in change from baseline to Week 16 in SNOT-22 score, with a 95% confidence interval from -7.6 to 7.1. The interval includes zero and values on both sides. The reported p-value is 0.950. Taken together, the registry analysis does not establish a clear between-group difference on this endpoint, while the interval also leaves uncertainty about the possible size and direction of a difference.

This is not evidence that GB001 and placebo are equivalent. Equivalence is a distinct conclusion that requires a prespecified acceptable-difference range and an analysis designed to evaluate that range. No such margin is reported in the registry record. Nor does a non-significant result prove that there is no effect; the interval indicates what range of contrasts is compatible with the analysis under its assumptions.

The change scores in both groups are negative, but within-group changes do not isolate the effect of treatment. Changes can reflect multiple influences, including the course of symptoms over time, study participation, and other factors shared by both groups. Randomized comparison is intended to separate the treatment contrast from common influences, and the reported between-group estimate is the relevant statistic for that question.

The findings apply to the recorded trial, its treatment regimens, endpoint timing, and analysis population. The record does not establish that the same result would hold in other populations, over another duration, or for outcomes not measured in this study. It also does not provide complete results for all secondary outcomes or the detailed missing-data and multiplicity methods needed for a broader confirmatory interpretation.

In general, statistical evidence and clinical importance are related but distinct. The registry does not report a threshold for a clinically important SNOT-22 change, so the score difference cannot be classified as clinically meaningful or unimportant from these statistics alone. The appropriate conclusion is limited: the reported analysis does not demonstrate a clear primary-endpoint difference, and its uncertainty does not establish equivalence or rule out all potentially meaningful differences.

14. Why This Trial Matters Statistically

This trial illustrates why a treatment-group comparison matters more than interpreting each group’s change in isolation. Both groups had negative average changes in SNOT-22 score, but the primary question concerns the difference between those changes. The reported contrast is close to zero, and its confidence interval communicates that the estimate is not precise enough to identify a clear direction.

It also illustrates the distinction between a p-value and an effect estimate. A p-value alone does not describe how large a difference might be or how uncertain that estimate is. Reading the mean difference together with its confidence interval gives a more informative account: the interval includes zero and extends to values favoring either group. That uncertainty is central to interpretation.

The endpoint is patient-reported, so it captures a quality-of-life dimension of chronic rhinosinusitis rather than only a clinical or imaging measure. The registry also lists outcomes covering symptoms, nasal polyps, smell, exacerbations, and safety. Such breadth can be valuable, but multiple outcomes require careful interpretation and transparent multiplicity methods. Those methods are not reported in the registry record.

Finally, the registry’s reported model-based analysis and analysis-population definition matter. A mixed models estimate is not necessarily interchangeable with a simple calculation from group summaries, and missing-data assumptions can affect model-based conclusions. The available information supports a bounded reading of the primary result, while leaving important details about modeling, missingness, and secondary analyses unreported.

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 registry record does not provide the full mixed models specification, including covariates and the structure used for repeated measurements. It also does not report the missing-data method, sensitivity analyses, or detailed handling of participants without a Week 16 measurement. These omissions make it difficult to assess the robustness of the model-based primary estimate independently.

The primary analysis population requires receipt of at least 1 dose and both baseline and post-baseline values, while the safety summaries use other at-risk counts. The registry does not explain the population differences. The reported endpoint counts should therefore be read in their own analysis context rather than treated as a common denominator across outcomes.

Several secondary results are not available as estimable two-arm comparisons in the registry record. The multiplicity plan and the trial’s own sample-size justification are also not reported. These gaps limit evaluation of the secondary findings and of the study’s original planning assumptions. The effect-based sample-size illustrations are not a substitute for a documented design rationale.

The record gives limited detail about event definitions, censoring, and model assumptions for time-to-event outcomes. It also does not report a clinically important threshold for the primary SNOT-22 change. These limitations do not alter the recorded primary estimate, but they constrain conclusions about the practical importance of the result, the completeness of the broader evidence, and how readily the analyses can be reproduced.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: GB001 in Adult Participants With Chronic Rhinosinusitis — NCT03956862.
• Registry record last updated 2021-08-23; status last verified 2021-08.
• Results first posted 2021-07-30.
• 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

This completed, randomized, double-blind, placebo-controlled Phase 2a study evaluated GB001 in adults with chronic rhinosinusitis with or without nasal polyps. Participants received GB001 40 mg once per day or placebo once per day for 16 weeks. The listed enrollment is 97.

The primary endpoint was change from baseline to Week 16 in SNOT-22 total score. The reported mean difference was -0.2, with a 95% confidence interval from -7.6 to 7.1 and p = 0.950. The interval includes zero and is consistent with uncertainty about the direction and size of the group difference.

The registry also lists secondary symptom, imaging, smell, response-time, exacerbation, and safety outcomes. Some secondary comparisons are not estimable or not fully reported. Detailed missing-data, multiplicity, and model-specification information is not reported in the registry record.