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 A Study Assessing the Efficacy and Safety of CBP-307 in Subjects With Moderate to Severe Ulcerative Colitis (UC) (NCT04700449), a randomized phase 2 study. The primary outcome is Change From Baseline for Adapted Mayo Score: 0.2 mg Versus Placebo.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04700449 |
| Phase | Phase 2 |
| Condition | Moderate to Severe Ulcerative Colitis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 145 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Connect Biopharm LLC |
| Results posted | Yes |
2. Clinical Question
Population
Subjects with moderate to severe ulcerative colitis. The registry record gives no further description of the primary analysis population beyond identifying it as the Full Analysis Set.
Intervention
The primary comparison concerns double-blind CBP-307 0.2 mg, given as oral capsules. The trial also included a double-blind 0.1 mg group and an open-label 0.2 mg group in Stage 2.
Comparator
The primary comparator was double-blind placebo, also given as oral capsules. The planned primary contrast was 0.2 mg CBP-307 versus placebo.
Primary question
At Week 12, how did change from baseline in adapted Mayo score compare between the 0.2 mg CBP-307 and placebo groups? The score combines stool frequency, rectal bleeding, and endoscopic findings; higher scores indicate more severe disease.
The registry describes a randomized, double-blind, placebo-controlled Phase II trial in subjects with moderate to severe ulcerative colitis. Its primary endpoint is a continuous measure: change from baseline in adapted Mayo score at Week 12. This asks whether the average change in the score differed between the 0.2 mg group and placebo during Stage 1. The posted primary outcome describes a least-squares mean and a 95% confidence interval for each group.
The clinical question is narrower than whether the treatment changes every aspect of ulcerative colitis. The adapted score uses three components, each scored from 0 to 3, and ranges from 0 to 9. It does not include every outcome that might matter to participants or clinicians. Secondary measures include clinical response and remission rates using adapted and complete Mayo scores, mucosal healing, and adverse events. The record does not report additional eligibility details or a more specific description of the population in the primary analysis.
3. Trial Design
This was a randomized, parallel-group, placebo-controlled Phase II trial sponsored by Connect Biopharm LLC. The registry lists an enrollment of 145 and a completed status. The recorded start date is 2019-02-27, and the primary completion date is 2022-02-23. The registry describes quadruple masking; further details about which roles were masked are not reported in the registry record.
Stage 1 included double-blind groups receiving 0.1 mg CBP-307, 0.2 mg CBP-307, or placebo. Stage 2 included double-blind 0.1 mg, double-blind 0.2 mg, and placebo groups, as well as an open-label 0.2 mg group. The primary endpoint specifically compares the double-blind 0.2 mg group with placebo at Week 12. Stage 1 outcomes were assessed at Week 12 or an early termination visit. The record also describes Week 24 assessment for sub-study 2 and Week 48 or an early termination visit during Stage 2.
The posted primary outcome is described as a comparison in the Full Analysis Set using multiple imputation. Group estimates are available for the primary endpoint, but a direct treatment contrast, its confidence interval, and a primary-endpoint p-value are not reported in the registry record. The record does not report the randomization procedure, allocation concealment details, or the reasons participants entered the Stage 2 open-label group. It also does not state the protocol’s sample-size justification or provide a full statistical analysis plan. Those omissions limit how completely the trial’s design and analysis choices can be evaluated from the registry record alone.
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: Because 1 subject in stage 1 placebo group was randomized but not treated, so the Enrollment number in the Protocol Section (145) conflicts with the number of participants Started in the Participant Flow module (144).
Stage 1: Double-Blind Period
| Stage | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| STARTED | 39 | 53 | 52 | 0 |
| COMPLETED | 28 | 50 | 47 | 0 |
| NOT COMPLETED | 11 | 3 | 5 | 0 |
Reasons for not completing this period:
| Reason | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| Adverse Event | 5 | 0 | 1 | 0 |
| Protocol Violation | 0 | 1 | 0 | 0 |
| Withdrawal by Subject | 2 | 2 | 2 | 0 |
| Lack of Efficacy | 1 | 0 | 0 | 0 |
| COVID-19 Restriction | 3 | 0 | 1 | 0 |
| Other | 0 | 0 | 1 | 0 |
Stage 2 Sub-study 1
| Stage | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| STARTED | 12 | 21 | 13 | 0 |
| COMPLETED | 10 | 17 | 9 | 0 |
| NOT COMPLETED | 2 | 4 | 4 | 0 |
Reasons for not completing this period:
| Reason | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| Adverse Event | 0 | 1 | 0 | 0 |
| Withdrawal by Subject | 1 | 1 | 1 | 0 |
| Lack of Efficacy | 0 | 0 | 2 | 0 |
| COVID-19 Restriction | 0 | 0 | 1 | 0 |
| Other | 1 | 2 | 0 | 0 |
Stage 2 Sub-study 2
| Stage | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 40 |
| COMPLETED | 0 | 0 | 0 | 17 |
| NOT COMPLETED | 0 | 0 | 0 | 23 |
Reasons for not completing this period:
| Reason | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Open-Label 0.2 mg CBP-307 |
|---|---|---|---|---|
| Adverse Event | 0 | 0 | 0 | 7 |
| Lost to Follow-up | 0 | 0 | 0 | 1 |
| Lack of Efficacy | 0 | 0 | 0 | 9 |
| COVID-19 Restriction | 0 | 0 | 0 | 1 |
| Other | 0 | 0 | 0 | 5 |
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: Because 1 subject in stage 1 placebo group was randomized but not treated, so the Overall Number of Baseline Participants in "Double-Blind Placebo" is greater than the number of participants included in the Participant Flow module.
| Characteristic | Unit | Double-Blind 0.1 mg CBP-307 | Double-Blind 0.2 mg CBP-307 | Double-Blind Placebo | Total |
|---|---|---|---|---|---|
| Participants analysed | 39 | 53 | 53 | 145 | |
| Age, Continuous | years | 42.9 (SD 13.41) | 42.1 (SD 10.66) | 41.2 (SD 9.86) | 42 (SD 11.14) |
| Sex: Female, Male: Female | Participants | 14 | 20 | 20 | 54 |
| Sex: Female, Male: Male | Participants | 25 | 33 | 33 | 91 |
| Race/Ethnicity, Customized: Asian | participants | 39 | 48 | 46 | 133 |
| Race/Ethnicity, Customized: Black or African American | participants | 0 | 0 | 1 | 1 |
| Race/Ethnicity, Customized: White | participants | 0 | 5 | 4 | 9 |
| Race/Ethnicity, Customized: Not Reported | participants | 0 | 0 | 2 | 2 |
| Race/Ethnicity, Customized: Hispanic or Latino | participants | 0 | 1 | 3 | 4 |
| Race/Ethnicity, Customized: Not Hispanic or Latino | participants | 39 | 52 | 50 | 141 |
| Adapt Mayo Score at Baseline | units on a scale | 6.00 (SD 1.485) | 5.84 (SD 1.361) | 5.93 (SD 1.178) | 5.92 (SD 1.325) |
| Complete Mayo Score at Baseline | units on a scale | 8.15 (SD 1.641) | 8.03 (SD 1.518) | 8.12 (SD 1.282) | 8.10 (SD 1.463) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline for Adapted Mayo Score: 0.2 mg Versus Placebo, measured over The adapted Mayo score was evaluated at screening and Week 12 (or early termination visit) during the study Stage 1 as well as at Week 24 (only for the sub-study 2) and Week 48 (or early termination visit) during the study Stage 2..
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is change from baseline in adapted Mayo score at Week 12. The adapted score combines stool frequency, rectal bleeding, and endoscopic findings. Its total ranges from 0 to 9, with each of the three subscores ranging from 0 to 3; higher values indicate more severe disease. Expressing the outcome as change from baseline focuses attention on how the score moved during the study rather than only on the Week 12 score.
The registry reports least-squares mean changes with 95% confidence intervals for the 0.2 mg CBP-307 and placebo groups. A least-squares mean is a model-based estimate of an average; the details of the model used for this primary estimate are not reported in the registry record. The primary outcome description says the analysis used the Full Analysis Set and multiple imputation. The confidence interval communicates uncertainty around each group estimate, but it is not itself the confidence interval for the difference between groups. A direct contrast would be needed to quantify the estimated between-group difference and its precision.
As a general interpretation, a reduction in this score corresponds to a change toward lower measured disease severity on the score’s scale. The endpoint is useful because it combines several specified clinical and endoscopic components into one continuous outcome, but a single score cannot capture every aspect of disease experience or safety. The registry record does not provide a primary-endpoint responder threshold or a stated clinically important difference.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
For the primary endpoint, the least-squares mean change was -2.6 in the double-blind 0.2 mg CBP-307 group, with a 95% confidence interval from -3.716 to -1.477. In the placebo group, the least-squares mean change was -1.95, with a 95% confidence interval from -3.073 to -0.834. Both group estimates are changes from baseline, not Week 12 scores. The negative values indicate decreases on the adapted Mayo scale as defined in the registry.
The intervals describe uncertainty around the separate group estimates. They do not directly estimate the treatment-versus-placebo contrast. The registry record does not report a primary-endpoint contrast estimate, a confidence interval for that contrast, or a p-value. It is therefore not possible to use the posted primary outcome alone to state the estimated size or statistical significance of the between-group difference. Overlap or non-overlap of separate group confidence intervals is not a substitute for a direct comparison, because the uncertainty of a contrast depends on the joint comparison and its analysis.
The secondary outcomes provide additional context. At Week 12, the posted summaries show higher response and remission percentages for the 0.2 mg group than for placebo under both adapted and complete Mayo definitions. The unadjusted recalculated risk-difference intervals for those comparisons exclude zero, and the associated unadjusted p-values are 0.037, 0.021, and 0.015 for adapted-score response, complete-score response, and adapted-score remission, respectively. These are simple unadjusted re-calculations from posted summary statistics, not reported sponsor analyses. The registry lists no reported analyses for those comparisons, and the unadjusted results should not be treated as definitive evidence, particularly in the presence of multiple outcomes and comparisons.
The 0.1 mg comparisons have less conclusive unadjusted results: their recalculated intervals include zero for the response and remission comparisons described in the posted secondary results. Such intervals are compatible with a range of possible differences, including little or no difference, as well as potentially meaningful differences in either direction. They do not establish equivalence or demonstrate absence of an effect.
These results should be read as estimates from a Phase II study with limited group sizes, alongside uncertainty and incomplete reporting of the inferential analysis. The primary outcome is described as using multiple imputation, but details of the imputation procedure and model are not reported in the registry record. The secondary comparisons are unadjusted, and a multiplicity strategy is not reported. Neither these results nor the safety summaries alone establish a comprehensive balance of benefit and harm.
9. Statistical Methods Explained
Several statistical ideas help distinguish what the registry reports from what can be concluded. The explanations of confidence intervals, group contrasts, missing-data methods, and planning calculations below are general statistical explanations. The trial-specific descriptions are limited to details stated in the registry record.
What does a confidence interval describe?
A confidence interval expresses the precision of an estimate under the assumptions of the method used to calculate it. A narrower interval indicates greater precision than a wider interval, while the interval’s endpoints indicate a range of values reasonably compatible with the estimate and its method. It is not a guarantee that the true value lies within that particular interval. The primary outcome reports a 95% confidence interval around each group’s least-squares mean change. Those intervals concern group estimates, rather than the difference between groups.
For a treatment comparison, the direct contrast is often the most useful quantity: it estimates how much the outcome differs between intervention and comparator groups. Its confidence interval describes uncertainty in that contrast. The registry record does not report this direct estimate for the primary endpoint, so the separate group intervals cannot provide a fully specified primary comparison. In general, visually comparing separate intervals is not equivalent to estimating a contrast, because the calculation needs to account for the uncertainty and relationship between the two group estimates.
What does the primary outcome estimate represent?
The primary outcome is identified as a least-squares mean change. In general, a least-squares mean is an average estimated from a statistical model, potentially adjusted for variables included in that model. The registry record does not identify the model covariates or give other details needed to reproduce the primary least-squares means. It states that the analysis used the Full Analysis Set and multiple imputation. Those labels give some information about the analysis, but do not fully specify model assumptions, handling of intercurrent events, or the imputation procedure.
The adapted Mayo score is continuous, so its group summaries describe average score changes rather than the proportions meeting a response threshold. Continuous outcomes retain information across the score’s range, but an average can conceal variation between participants. The registry record does not post participant-level distributions or a dispersion statistic alongside the primary least-squares means; it reports confidence intervals instead.
How should the secondary risk differences be read?
The secondary outcomes include binary response and remission measures expressed as percentages. A risk difference is the difference between the proportions in two groups, expressed on the probability scale. Its confidence interval indicates uncertainty in that difference. An interval that includes zero is compatible with no difference under the calculation; an interval excluding zero indicates a nonzero difference under that unadjusted calculation. This interpretation does not by itself establish clinical importance, account for all design features, or correct for testing multiple outcomes.
The secondary risk differences and p-values are recalculated from the posted summary statistics and are identified as unadjusted. They are not the registry’s reported sponsor analyses: the registry lists no reported analyses for these outcomes. Simple recalculations are useful for describing the posted counts and percentages in a consistent comparison, but they may not reproduce a prespecified trial analysis. If a discrepancy were identified, the sponsor’s own analysis would take precedence; the discrepancy indicator is false for this record.
Why does multiplicity matter?
When many endpoints, doses, time points, or contrasts are examined, the chance of observing a nominally small p-value by chance can increase. A multiplicity procedure can address this, but may change which comparisons are treated as confirmatory and how uncertainty is quantified. The registry record lists multiple secondary outcomes and does not report a multiplicity adjustment or testing hierarchy. Consequently, the unadjusted secondary p-values are best treated as exploratory signals rather than as independently confirmatory findings. The exact prespecified testing plan is not reported in the registry record.
What do the planning illustrations mean?
The per-arm sample-size illustrations are planning examples calculated from observed effects, not estimates of the trial’s observed power and not the trial’s own design justification. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and detection of a stated fraction of the observed effect. The illustrations show how the required number of participants per arm changes when planning for 100%, 75%, or 50% of an observed effect. They depend on the observed effect being a suitable basis for planning; estimates from a study can be imprecise, and planning around them does not guarantee a future study will detect an effect.
For binary comparisons, the posted illustrations express participants per arm for 80% power and participants per arm for 90% power. These are planning targets under the listed assumptions, not evidence that the current trial had those power levels. The registry record’s enrollment and observed group sizes are separate details from these hypothetical planning calculations. The record does not report its original sample-size justification or whether any interim analyses were planned or conducted.
10. Multiplicity, Missing Data and Analysis Populations
The registry record reports that the primary outcome was assessed in the Full Analysis Set using multiple imputation. It does not report the number of imputed datasets, the variables used in the imputation model, the assumptions about missingness, or the method for combining estimates across imputations. It also does not describe sensitivity analyses for departures from the imputation assumptions. These omissions make it difficult to assess how missing outcome data may have affected the primary estimate.
The primary outcome timeframe includes Week 12 or an early termination visit in Stage 1. The registry describes Stage 2 follow-up at Week 24 for sub-study 2 and Week 48 or an early termination visit, but the primary comparison is at Week 12. The detailed rules for which observed or imputed measurements contributed to the Week 12 analysis are not reported in the registry record. The analysis populations for the posted secondary outcomes are also not specified in the available record.
The registry lists numerous secondary outcomes and results at Week 12, with dose comparisons against placebo. A multiplicity adjustment, testing hierarchy, or designation of which secondary analyses were confirmatory is not reported in the registry record. The secondary risk-difference p-values discussed in the statistical interpretation are unadjusted recalculations; they should not be read as multiplicity-controlled evidence.
The registry record also does not report the full statistical analysis plan, a primary contrast estimate or p-value, or the analysis model details for the least-squares means. Interim analyses and any associated decision rules are not reported in the registry record. Without these details, readers cannot fully establish whether the posted summaries reflect prespecified methods, how all missing data were handled, or how the overall family of comparisons was intended to be interpreted.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Stage 1 Double-Blind 0.1 mg CBP-307 | 6 | 39 | 15.4% |
| Stage 1 Double-Blind 0.2 mg CBP-307 | 2 | 53 | 3.8% |
| Stage 1 Double-Blind Placebo | 3 | 52 | 5.8% |
| Stage 2 Double-Blind 0.1 mg CBP-307 | 0 | 12 | 0.0% |
| Stage 2 Double-Blind 0.2 mg CBP-307 | 1 | 21 | 4.8% |
| Stage 2 Double-Blind Placebo | 0 | 13 | 0.0% |
| Stage 2 Open-label 0.2 mg CBP-307 | 8 | 40 | 20.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Stage 1 Double-Blind 0.1 mg CBP-307 | 0 of 39 |
| Stage 1 Double-Blind 0.2 mg CBP-307 | 0 of 53 |
| Stage 1 Double-Blind Placebo | 0 of 52 |
| Stage 2 Double-Blind 0.1 mg CBP-307 | 0 of 12 |
| Stage 2 Double-Blind 0.2 mg CBP-307 | 0 of 21 |
| Stage 2 Double-Blind Placebo | 0 of 13 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Stage 1 Double-Blind 0.1 mg CBP-307 | 37 of 39 |
| Stage 1 Double-Blind 0.2 mg CBP-307 | 47 of 53 |
| Stage 1 Double-Blind Placebo | 40 of 52 |
| Stage 2 Double-Blind 0.1 mg CBP-307 | 11 of 12 |
| Stage 2 Double-Blind 0.2 mg CBP-307 | 20 of 21 |
| Stage 2 Double-Blind Placebo | 12 of 13 |
Most frequent serious adverse event terms
| Event term | Organ system | Stage 1 Double-Blind 0.1 mg CBP-307 | Stage 1 Double-Blind 0.2 mg CBP-307 | Stage 1 Double-Blind Placebo | Stage 2 Double-Blind 0.1 mg CBP-307 | Stage 2 Double-Blind 0.2 mg CBP-307 | Stage 2 Double-Blind Placebo |
|---|---|---|---|---|---|---|---|
| Colitis ulcerative | Gastrointestinal disorders | 4 of 39 | 2 of 53 | 2 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Gastritis | Gastrointestinal disorders | 1 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Transitional cell carcinoma | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 1 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Ovarian cyst | Reproductive system and breast disorders | 0 of 39 | 0 of 53 | 1 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Appendicitis | Infections and infestations | 0 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 1 of 21 | 0 of 13 |
| Large intestine polyp | Gastrointestinal disorders | 0 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Anal abscess | Infections and infestations | 0 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Cholera | Infections and infestations | 0 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
| Cytomegalovirus infection | Infections and infestations | 0 of 39 | 0 of 53 | 0 of 52 | 0 of 12 | 0 of 21 | 0 of 13 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Stage 1 Double-Blind 0.1 mg CBP-307 | Stage 1 Double-Blind 0.2 mg CBP-307 | Stage 1 Double-Blind Placebo | Stage 2 Double-Blind 0.1 mg CBP-307 | Stage 2 Double-Blind 0.2 mg CBP-307 | Stage 2 Double-Blind Placebo |
|---|---|---|---|---|---|---|---|
| Gastrointestinal disorders | Gastrointestinal disorders | 12 of 39 | 16 of 53 | 14 of 52 | 4 of 12 | 11 of 21 | 3 of 13 |
| Investigations | Investigations | 13 of 39 | 18 of 53 | 9 of 52 | 5 of 12 | 9 of 21 | 3 of 13 |
| Infections and infestations | Infections and infestations | 14 of 39 | 13 of 53 | 15 of 52 | 2 of 12 | 6 of 21 | 6 of 13 |
| Eye disorders | Eye disorders | 5 of 39 | 11 of 53 | 10 of 52 | 5 of 12 | 7 of 21 | 5 of 13 |
| Cardiac disorders | Cardiac disorders | 9 of 39 | 13 of 53 | 6 of 52 | 4 of 12 | 4 of 21 | 2 of 13 |
| Nervous system disorders | Nervous system disorders | 6 of 39 | 8 of 53 | 9 of 52 | 1 of 12 | 5 of 21 | 1 of 13 |
| Skin and subcutaneous tissue disorders | Skin and subcutaneous tissue disorders | 9 of 39 | 5 of 53 | 4 of 52 | 5 of 12 | 2 of 21 | 1 of 13 |
| Respiratory, thoracic and mediastinal disorders | Respiratory, thoracic and mediastinal disorders | 6 of 39 | 6 of 53 | 5 of 52 | 3 of 12 | 5 of 21 | 1 of 13 |
| Blood and lymphatic system disorders | Blood and lymphatic system disorders | 6 of 39 | 4 of 53 | 8 of 52 | 1 of 12 | 3 of 21 | 0 of 13 |
| General disorders and administration site conditions | General disorders | 5 of 39 | 7 of 53 | 4 of 52 | 1 of 12 | 4 of 21 | 0 of 13 |
Serious events with the highest arm-level rate: colitis ulcerative (15.0%), appendicitis (4.8%), gastritis (2.6%), transitional cell carcinoma (2.6%), large intestine polyp (2.5%).
The registry posts serious adverse event figures by stage and group, along with counts at risk and counts with other adverse events. In Stage 1, serious adverse events were reported for 6 participants in the 0.1 mg group, 2 in the 0.2 mg group, and 3 in the placebo group. In Stage 2, the figures were 0 in the 0.1 mg group, 1 in the 0.2 mg group, 0 in the placebo group, and 8 in the open-label 0.2 mg group. The posted death count is 0 for each listed group. These are descriptive counts; the Stage 2 open-label group is not the same kind of randomized, blinded comparison as the Stage 1 groups.
The record lists serious-event terms including colitis ulcerative at 15.0%, appendicitis at 4.8%, gastritis at 2.6%, transitional cell carcinoma at 2.6%, large intestine polyp at 2.5%, and anal abscess at 2.5%. These percentages do not by themselves establish that an event was caused by treatment. The registry does not provide sufficient detail in these summaries to assess timing, exposure duration, event-level overlap, or attribution. Counts from different stages or groups should not be combined to create a new overall rate. Adverse-event summaries describe reported events and should be considered alongside the trial’s design and the limits of the posted safety information.
12. What the Result Does, and Does Not, Mean
The posted results describe group-level changes and proportions, not what happened to every individual participant. For the primary endpoint, each group’s estimated adapted Mayo score change was negative, and the group confidence intervals express uncertainty around those separate estimates. The registry record does not report the direct primary treatment contrast, so it does not provide the most direct estimate of how much the 0.2 mg group differed from placebo at Week 12.
The secondary results show a pattern in which the posted Week 12 response and remission percentages for the 0.2 mg group are higher than the placebo percentages. Unadjusted recalculations produce intervals and p-values for some comparisons, but these do not account for the full set of outcomes and comparisons. The registry does not report a multiplicity plan or sponsor analyses for these comparisons. These findings therefore should not be treated as definitive confirmation, nor should an interval that includes zero be interpreted as proof of no difference.
Statistical evidence and clinical importance are related but not interchangeable. A confidence interval helps convey precision, while a clinical interpretation also depends on the scale, the relevance of its components, and what degree of change matters to participants. The registry record does not state a clinically important difference or a primary endpoint response threshold. Nor do the posted results establish how well the findings generalize beyond the trial population, for which detailed eligibility characteristics are not reported in the registry record.
The safety counts are descriptive and cannot alone establish a causal relationship between treatment and any event. The summaries do not provide a complete account of event timing, severity patterns, exposure, or comparative safety analysis. Taken together, the registry record offers outcome estimates that can be interpreted with caution, but it does not contain every analysis detail needed for a definitive assessment of efficacy or safety.
13. Why This Trial Matters Statistically
This trial raises several statistical questions that are common in clinical research. The primary endpoint is a continuous score, yet the registry posts separate group estimates without a direct contrast. A treatment comparison is easiest to interpret when the estimated between-group difference and its uncertainty are reported directly. Without them, readers can describe the two group changes but cannot quantify the primary comparison from the registry record.
The trial also includes multiple doses, stages, and secondary definitions of response and remission. Those features create a family of related comparisons. A prespecified analysis strategy can clarify which outcome is primary, how secondary outcomes support interpretation, and how multiplicity is handled. That strategy is not reported in the registry record. The recalculated secondary results are useful for exploring the posted data, but their unadjusted nature and absence of reported sponsor analyses limit their confirmatory role.
Missing-data methods matter because the primary analysis is described as using multiple imputation. Imputation can allow incomplete observations to contribute under stated assumptions, but readers need details about the model and assumptions to assess robustness. Those particulars are not reported. Likewise, the least-squares mean label indicates model-based estimation, but the model details are unavailable.
Finally, planning calculations based on observed effects illustrate how sample-size targets depend on the effect a future study aims to detect. They are not the original design rationale and do not say whether this completed trial was adequately powered. These distinctions—estimate versus contrast, exploratory versus confirmatory analysis, and planning illustration versus observed power—are central to reading registry results responsibly.
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.
Important details about the trial and its analysis are not reported in the registry record. The record does not provide detailed eligibility criteria, baseline characteristics, or an account of participant flow by group. Although enrollment is listed as 145, the posted primary outcome gives its own group sizes, and the record does not provide enough information to reconstruct all analysis populations or explain differences between enrollment and outcome denominators.
The primary outcome is reported as group least-squares mean changes with confidence intervals, but no direct contrast, confidence interval for the contrast, or p-value is posted. The model underlying the least-squares means is not described. Multiple imputation is identified, but its assumptions, implementation, and sensitivity analyses are not. The registry does not report a clinically important difference for the adapted Mayo score, which limits interpretation of the practical importance of the estimates.
The secondary outcome record is also incomplete for interpretation. Although mucosal healing and adverse events are listed among outcomes, numerical mucosal healing results are not available in the registry record used for this analysis. The secondary comparisons have no reported sponsor analyses, and their recalculated results are unadjusted. A multiplicity plan and full statistical analysis plan are not reported. The trial’s randomization procedure, allocation concealment, detailed masking procedures, and rationale for the Stage 2 open-label group are not described.
Safety summaries are presented by stage and group but do not fully characterize event timing, duration of exposure, attribution, or overlap among terms. The open-label group also does not offer the same blinded comparison as the double-blind groups. These reporting limits mean that the posted numbers should be treated as a partial statistical account rather than a complete basis for causal or clinical conclusions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study Assessing the Efficacy and Safety of CBP-307 in Subjects With Moderate to Severe Ulcerative Colitis (UC) — NCT04700449.
- Registry record last updated 2024-05-06; status last verified 2024-04.
- Results first posted 2023-11-02.
- 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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18. Record Summary
The registry describes a completed, randomized, parallel-group, quadruple-masked Phase II study of CBP-307 in subjects with moderate to severe ulcerative colitis. The primary comparison is double-blind 0.2 mg CBP-307 versus placebo for Week 12 change from baseline in adapted Mayo score. The primary outcome reports separate least-squares mean changes and 95% confidence intervals, with analysis described as using the Full Analysis Set and multiple imputation.
The registry also posts Week 12 secondary response and remission outcomes, and safety summaries by stage and group. Direct primary contrast results, detailed analysis methods, multiplicity handling, and several missing-data details are not reported in the registry record. Secondary recalculations are unadjusted and do not replace reported sponsor analyses.