Omalizumab in Chronic Spontaneous Urticaria Patients Non Responding to Initial Standard antihistaminE Treatment: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Omalizumab in Chronic Spontaneous Urticaria Patients Non Responding to Initial Standard antihistaminE Treatment (NCT02550106), a non-randomized phase 4 study. The primary outcome is Percent of Participants With an Urticaria Control Test [UCT] Score of Greater Than or Equal to 12.

2. Clinical Question

This is a question about the observed level of symptom control at a specified follow-up time in a treated group. It is not a randomized comparison of omalizumab with placebo or another treatment. Consequently, the primary outcome, if reported, would describe the participants in this study and would not by itself estimate how their outcomes would differ under a different treatment.

The registry describes the UCT as a four-item instrument. Each answer option receives a score from 0 to 4, and the scores are summed. The total can range from 0 to 16, with 16 indicating complete disease control. The primary threshold of at least 12 therefore classifies participants according to whether their total score reached the stated level at Week 12. It does not describe the size of any change from baseline, and the registry record does not give the baseline distribution or primary result.

Other listed outcomes address UAS7, UCT scores at several follow-up times, outcomes according to angioedema status, and quality of life. They broaden the range of questions assessed, but the registry does not report their results or analyses.

3. Trial Design

This was a Phase IV, multicenter, single-arm, open-label study of omalizumab in chronic spontaneous urticaria. The registry lists non-randomized allocation and a single-group model. With no separate control arm, the design can describe outcomes among participants receiving the study treatment, but it cannot provide a randomized, like-for-like estimate of a treatment contrast.

The registry records an enrollment of 136 and a completed study. The recorded start date is 2015-04-22, and the primary completion date is 2016-01-11. Participants were assigned to the omalizumab group, described as receiving subcutaneous injections of 300 mg every 4 weeks until Week 8. The study is identified as open-label; although the masking field is recorded as single, who was masked and how masking was implemented are not reported in the registry record.

The primary outcome was the percentage of participants whose UCT score was at least 12 at Week 12. The stated primary outcome population is the full analysis set, using last observation carried forward. The record does not provide the number included in that analysis, the number with observed Week 12 measurements, or the number whose values were carried forward.

The registry lists 12 outcome measures and 0 analysis records. Listed secondary outcomes include UAS7 disease activity and disease control, UCT outcomes by angioedema status, UCT at later visits during an extension treatment period, and chronic urticaria quality of life. Outcome titles alone do not establish which analyses were conducted or what they found. Details such as the sample-size justification, detailed statistical plan, and any interim analyses 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: (Full analysis set, LOCF)

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 Percent of Participants With an Urticaria Control Test [UCT] Score of Greater Than or Equal to 12, measured over WEEK 12.

The primary endpoint is the percentage of participants with a UCT score of at least 12 at Week 12. It converts participants’ questionnaire scores into a binary classification: meeting the stated threshold or not meeting it. The underlying UCT has four items, each scored from 0 to 4, with item scores summed to a total between 0 and 16. A score of 16 represents complete disease control according to the registry description.

A threshold-based endpoint can make a result easier to interpret as the proportion of a study group reaching a defined level of control. However, it does not retain all the information in the original score. Participants just below the threshold and participants with much lower scores are grouped together, as are those at the threshold and those with higher scores. The percentage also does not show how much any participant’s score changed from baseline.

The endpoint is measured at Week 12, after the described treatment schedule through Week 8. The registry identifies the full analysis set with last observation carried forward as the population and missing-data approach for this endpoint. The count meeting the threshold, the analysis denominator, the percentage, and its 95% confidence interval are not reported in the registry record. Thus, the endpoint’s definition is available, but its observed result and precision cannot be assessed from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a binary percentage endpoint: whether a participant’s Week 12 UCT score reached the threshold of at least 12. In general, a binary endpoint is summarized by counting participants in each category and expressing the count meeting the criterion relative to the relevant analysis population. The registry record does not report those counts or the resulting percentage for this endpoint, so no numerical estimate can be interpreted.

What does the confidence interval describe?

The primary endpoint lists a 95% confidence interval as its measure of dispersion. In general, a confidence interval accompanies an estimate to convey how much uncertainty remains about the corresponding population quantity under the method’s assumptions. It is not a range containing 95% of individual participants’ outcomes, nor does it correct for shortcomings in the design or measurement. Its interpretation depends on the estimate, the analysis population, the method used to construct the interval, and the data. The interval and its calculation method are not reported in the registry record.

For a proportion, different interval procedures can behave differently, particularly when the count is small or the estimate is near a boundary. The registry record does not identify which procedure was used. It also does not report whether the analysis accounted for any features beyond the stated full analysis set and last observation carried forward. Therefore, the stated confidence level alone is not enough to reproduce or evaluate the uncertainty calculation.

What does a single-group design allow?

In general, a single-group study estimates outcomes in the group observed under the study conditions. A randomized control group helps distinguish treatment-associated outcomes from changes that might have occurred without the treatment or under another treatment. Here, the registry identifies a non-randomized, single-group design and no comparator. A percentage reaching the UCT threshold would therefore be a within-group descriptive result, not a randomized treatment contrast. Statistical adjustment cannot create the missing randomized comparison unless additional data and assumptions are available; no such adjustment is described in the registry record.

The study is described as open-label, while the masking field is recorded as single. The identity of any masked party and the procedures used are not reported. In general, knowledge of treatment assignment can influence subjective reporting, participant expectations, or outcome assessment, depending on the measurement process. This is a methodological consideration, not evidence that such influence occurred in this study.

How should missing-data handling be understood?

The primary outcome population is stated as the full analysis set, with last observation carried forward (LOCF). In general, LOCF substitutes a participant’s last recorded outcome for a later missing measurement under the analysis rule. This can preserve records in an analysis, but it treats the carried-forward value as if it represents the later time point. That assumption may not fit the participant’s actual course, especially when the outcome can change over time. LOCF does not recover an unobserved Week 12 score; it creates an analysis value according to a specified convention.

The record does not report how many Week 12 scores were missing, how many values were carried forward, why observations were missing, or whether sensitivity analyses using other assumptions were performed. Without those details and the primary estimate, it is not possible to assess how much the endpoint result might depend on the missing-data rule. The detailed definition of the full analysis set is also not reported.

What can planning calculations say?

General sample-size calculations can illustrate how many participants per arm might be needed under stated assumptions, such as a two-sided significance level of 0.05, equal allocation, a normal approximation, and a target effect expressed as a fraction of an observed effect. Such calculations are planning illustrations, not observed power and not necessarily the original trial’s design rationale. The registry record does not report a sample-size justification or a statistical plan establishing that these assumptions governed the trial. It also does not report a randomized two-arm comparison for this study; a two-arm planning calculation does not change the actual single-group design or create a comparator.

More generally, planning results depend on the target effect, variability or event rate, design, and analysis assumptions. If an assumed effect differs from the effect a future study aims to detect, the planning result changes. Any illustration based on a previously observed effect is conditional on that estimate and should not be read as proof that a study had adequate power or that an effect was observed in this trial. The primary outcome result needed to judge the observed effect is not reported in the registry record.

Why do analysis choices matter?

In general, prespecifying the outcome, population, missing-data approach, and statistical method helps readers distinguish planned analyses from exploratory ones. The registry gives the primary endpoint definition and names the analysis population and LOCF approach, but a detailed statistical analysis plan is not reported. The record lists 12 outcome measures and 0 analysis records. It does not describe multiplicity adjustment, interim analyses, subgroup-analysis procedures, or the calculation method for the confidence interval. These omissions limit the ability to evaluate how the reported endpoint was selected and analyzed, even though the endpoint itself is clearly defined.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("OMALIZUMAB With ANGIOEDEMA")
n      <- c(136)
events <- c(102)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  OMALIZUMAB With ANGIOEDEMA  136  102  75.0  66.9  82.0  67.1  81.5  67.1  81.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures, including the primary Week 12 UCT threshold and secondary measures involving UAS7, UCT, angioedema status, later extension-period visits, and quality of life. When several outcomes or subgroup comparisons are examined, the chance of at least one apparently notable result can increase. In general, prespecified testing strategies or multiplicity adjustments can address this issue, depending on the aims of the analyses. Whether any such strategy was planned or used is not reported in the registry record. The record also lists 0 analysis records, so it does not give analysis results across the outcomes that could be evaluated for consistency.

The primary population is identified as the full analysis set, with last observation carried forward. The number included in that set, the Week 12 observed-data count, and the amount or reasons for missingness are not reported. The record does not state whether alternative missing-data approaches or sensitivity analyses were used. In general, missing-data methods rely on assumptions about unobserved measurements; LOCF is one convention and does not demonstrate that a carried-forward score equals the score that would have been observed at Week 12.

The registry record does not report a detailed statistical analysis plan, interim analyses, or a sample-size justification. This means readers cannot determine from the record whether additional analysis decisions were made before outcomes were examined or how those decisions may have affected interpretation. The outcome definitions remain informative, but the missing results and analysis details prevent assessment of statistical significance, robustness to missingness, or the handling of multiple outcomes.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

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: pneumonia (0.7%), cervical vertebral fracture (0.7%), fractured sacrum (0.7%), ligament sprain (0.7%), obesity (0.7%).

The safety record lists 9 participants with serious adverse events among 136 at risk and 44 participants with other adverse events among 136 at risk. These are participant counts in separate categories; they should not be added together because the record does not say whether the categories overlap. The listed serious adverse-event terms are pneumonia, cervical vertebral fracture, fractured sacrum, ligament sprain, obesity, and foot deformity, each reported at 0.7%.

These entries are descriptive. The registry record does not report event-level timing, duration, severity details beyond the serious-event classification, or whether investigators considered an event related to treatment. It also provides no comparator group for contextualizing the counts. The death entry is not reported in the registry record.

In general, an adverse event recorded during a study is not by itself proof that the study treatment caused it. Conversely, the absence of a reported causal link would not establish that treatment played no role. The reported counts and terms should therefore be read as registry safety information, not as a comparative risk estimate or a causal conclusion.

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

The registry record identifies what the primary endpoint was intended to measure: the proportion of participants with a UCT score of at least 12 at Week 12. It also specifies the treatment group, the endpoint population as the full analysis set, and use of last observation carried forward. However, the actual primary outcome percentage, its numerator and denominator, and its 95% confidence interval are not reported in the registry record. Without those results, the primary endpoint cannot be characterized as high or low, precise or imprecise, or statistically distinguishable from any reference value.

Even if the endpoint result were available, its interpretation would be limited by the design. This was a non-randomized, single-group study without a comparator. A group’s outcome proportion does not establish how outcomes would have differed under another treatment or without the study treatment. The record also does not report baseline UCT results or individual changes, so it cannot show the amount of change from baseline using the primary endpoint definition alone.

The endpoint threshold is one way to summarize the UCT, but it compresses a score ranging from 0 to 16 into a yes-or-no classification. In general, threshold-based summaries can be useful for communicating whether a stated criterion was reached, while obscuring differences within each category and changes that do not cross the threshold. The registry describes the scale and threshold, but not the distribution of Week 12 scores.

The safety counts and serious-event terms provide additional descriptive information. They do not establish whether events were caused by treatment, and the absence of a control group makes comparative safety interpretation unavailable from this record. The record does not report deaths.

Accordingly, the registry supports an account of the intended question and broad design, but not a conclusion about the primary outcome’s observed value, precision, comparative effect, or causal meaning. Those are distinct questions, and the available registry information does not resolve them.

14. Why This Trial Matters Statistically

This study illustrates an important distinction between describing outcomes and estimating comparative effects. A single-group study can document what happened among participants treated in a particular study setting. It cannot, on its own, separate treatment-associated outcomes from other explanations as effectively as a randomized comparison. This distinction is essential when interpreting percentages: a clear endpoint definition does not make the result comparative.

The primary endpoint also highlights how measurement choices shape interpretation. The UCT is a multi-item score, while the primary outcome classifies participants at a threshold of at least 12. That format is straightforward to describe, but it discards information about the exact score and change from baseline. The registry’s description of the scale makes the threshold understandable; the absence of the result means its observed distribution and precision remain unknown.

Missing-data handling matters as well. The record identifies LOCF for the full analysis set, but does not report the amount of missing data or sensitivity analyses. In general, an analysis convention cannot substitute for observing the outcome, and readers need information about missingness to judge how dependent a result may be on its assumptions.

Finally, the record lists multiple outcomes but no analysis records. Outcome definitions can show what investigators intended to assess, but they do not establish findings or explain which analyses were emphasized. Together, these features make the study a useful example of why design, endpoint definition, analysis population, missing-data assumptions, and result reporting must be considered separately. Statistical interpretation depends on all of them, not just the treatment name or the stated endpoint.

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 central limitation for interpreting the primary question is that its result is not reported in the registry record. The percentage meeting the Week 12 UCT threshold, the corresponding count and denominator, and the stated 95% confidence interval are absent. Enrollment of 136 does not establish how many participants contributed to the primary analysis or had a Week 12 measurement.

The study is single-arm and non-randomized, with no comparator. As a result, it cannot provide a randomized estimate of differences between omalizumab and another treatment. The open-label description is also relevant to interpretation of participant-reported or otherwise judgment-dependent measures, while the identity of any masked party under the single-masking field is not reported.

The primary endpoint uses the full analysis set with LOCF, but the analysis-set definition, number of missing Week 12 scores, reasons for missingness, and any sensitivity analyses are not reported. The registry lists multiple outcomes, yet does not report their analyses or whether multiplicity was addressed. A detailed statistical analysis plan, interim analyses, and sample-size justification are also not reported in the registry record.

Additional limits include the absence of reported baseline UCT distributions and score changes, which restricts interpretation of the threshold outcome as a change measure. Safety information is descriptive and lacks a comparator and reported treatment attribution. These limitations do not establish that the study was poorly conducted; they identify what cannot be assessed from the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Omalizumab in Chronic Spontaneous Urticaria Patients Non Responding to Initial Standard antihistaminE Treatment — NCT02550106.
• Registry record last updated 2020-02-25; status last verified 2020-02.
• Results first posted 2020-02-25.
• 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

The registry describes a completed Phase IV, multicenter, open-label, non-randomized, single-group study of omalizumab for chronic spontaneous urticaria in people who remained symptomatic despite H1 antihistamine treatment. The recorded enrollment is 136. The intervention is described as subcutaneous omalizumab 300 mg every 4 weeks until Week 8.

The primary endpoint is the percentage with a UCT score of at least 12 at Week 12. Its stated population is the full analysis set, using last observation carried forward. The primary result and its 95% confidence interval are not reported in the registry record. The record lists 12 outcome measures and 0 analysis records.

Safety entries include 9 participants with serious adverse events and 44 with other adverse events, with 136 at risk in each category. The record lists several serious-event terms, each at 0.7%, and does not report deaths. The single-group design and missing outcome results limit interpretation of efficacy and comparative safety.