Efficacy and Safety of Omalizumab in Adults (18-70 Years) With Moderate to Severe Chronic Urticaria: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of Omalizumab in Adults (18-70 Years) With Moderate to Severe Chronic Urticaria (NCT00481676), a randomized phase 2 study. The primary outcome is Change in the Weekly Urticaria Activity Score (UAS7) From Baseline to the End of the Study (Week 24).

2. Clinical Question

The clinical question is narrowly framed around adults with chronic urticaria who exhibit IgE against thyroperoxidase, rather than chronic urticaria broadly. The registry describes the study as a Phase 2, 24-week investigation of efficacy and safety. It lists 49 participants enrolled. The primary outcome is a change score, so the comparison concerns how much the weekly activity score changed during follow-up in each group, not simply the score at the end of follow-up.

The posted primary group means are negative in both arms, which indicates a reduction from baseline under the endpoint definition. The comparison focuses on the difference in those mean changes. These data describe the trial population and follow-up recorded in the registry; they do not by themselves establish how the findings apply to people outside the eligibility characteristics or study setting.

3. Trial Design

This was a randomized, parallel-group, placebo-controlled study with quadruple masking. Its official title describes a multicenter, double-blind study lasting 24 weeks. The registry identifies it as Phase 2 and lists chronic urticaria as the condition. The study evaluated omalizumab in adult patients with moderate to severe chronic urticaria who exhibit IgE against thyroperoxidase.

Participants were assigned to omalizumab 75-375 mg or placebo to omalizumab. For both arms, the registry describes dosing according to baseline IgE and body weight, with subcutaneous administration every 2 or 4 weeks depending on dose. The registry also lists loratadine and clemastine as interventions, but their roles and use within the study are not reported in the registry record. The details of masking roles beyond the registry’s quadruple-masking designation are not reported in the registry record.

The registry lists enrollment as 49. The posted primary outcome groups contain 27 participants in the omalizumab arm and 22 in the placebo arm. The primary outcome timeframe is baseline to the end of the study at Week 24. The outcome population is defined as the intent-to-treat population consisting of randomized patients who received at least one dose and had at least one post-baseline primary efficacy assessment.

The recorded start was 2007-05, primary completion was 2009-04, and the status is completed. The registry record does not report the original sample-size justification, the allocation procedure in greater detail, or the statistical analysis plan. It also does not report whether interim analyses were planned or conducted. These omissions mean that the design can be described from the recorded features, but the rationale for the planned enrollment and the full analysis strategy cannot be reconstructed from 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: Intent-to-treat (ITT) population: All randomized patients who received at least 1 dose of study drug and had at least 1 post-baseline assessment of the primary efficacy variable.

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 in the Weekly Urticaria Activity Score (UAS7) From Baseline to the End of the Study (Week 24), measured over Baseline to end of the study (Week 24).

The primary endpoint is change in the Weekly Urticaria Activity Score, or UAS7, from baseline to Week 24. The score is built from diary-recorded daily ratings of wheals and pruritus. Each component receives a severity rating from 0=none to 3=intense. The two daily ratings are added to create a daily UAS, and the daily scores across a week are summed to form UAS7. Its range is 0 to 42 per week, with higher values indicating worse disease activity.

Using a change score makes the outcome about the difference between a participant’s baseline and end-of-study scores. Under the registry’s definition, the change is the Week 24 score minus the baseline score. A negative change therefore indicates improvement. The reported arm means summarize those changes across participants; they do not describe every individual’s experience or the distribution of individual responses.

A weekly measure is used because chronic urticaria activity can vary over time. Combining daily ratings over a week provides a summary of wheals and pruritus across that period rather than relying on a single daily observation. General statistical context: a continuous outcome such as UAS7 can be summarized by its mean and standard deviation, which describe the average change and the spread of participant changes around that average. The registry does not report additional details about diary completion or how incomplete diary data were handled.

7. Results Posted in the Registry

• Omalizumab 75-375 mg: mean -17.80 versus -5.80 on control; difference -12.00 (95% CI -18.24 to -5.76), standardized effect d = -1.09; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Standardized (With Respect to Length of Time) Area Under the Curve (AUC) for the Urticaria Activity Score (UAS) From Baseline to the End of the Study (Week 24)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Omalizumab 75-375 mg: mean 1.00 versus 2.50 on control; difference -1.50 (95% CI -2.21 to -0.79), standardized effect d = -1.19; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Omalizumab 75-375 mg than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry lists secondary outcomes covering urticaria activity, symptoms, rescue and concomitant medication use, quality of life, and global assessments by patients and investigators. The breadth of these measures reflects several related aspects of chronic urticaria, but a list of outcomes is not the same as a complete set of reported results. Only one secondary outcome has posted comparative summary statistics in the registry record: the standardized area under the curve for UAS from baseline to Week 24. The other listed secondary outcome results are not reported in the registry record.

The available numeric secondary comparison is directionally consistent with the primary result: the activity summary is lower in the omalizumab arm than in the placebo arm. This provides a related measure of urticaria activity, but it is not an independent replication of the primary endpoint. Both outcomes concern urticaria activity, and the secondary measure covers the same baseline-to-Week-24 period. It should therefore be treated as supportive context rather than as a separate confirmation that removes uncertainty in the primary comparison.

General statistical context: when many outcomes are examined, the chance of finding at least one apparently notable result can rise unless the analysis plan accounts for multiplicity. A prespecified hierarchy, adjustment method, or clear distinction between confirmatory and exploratory outcomes can help readers interpret a family of results. Such details are not reported in the registry record. The secondary results should consequently carry less inferential weight than a fully specified, multiplicity-controlled analysis would warrant.

Because the record does not report results for the other named measures, there is no basis to infer a consistent pattern across symptoms, medication use, quality of life, or global assessments. Their presence in the registry indicates planned outcome domains, not that the results favored either group. The available evidence across secondary endpoints is therefore limited to the reported activity summary, with interpretation constrained by incomplete reporting and the absence of a documented multiplicity plan.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Patients With Wheals, Erythemas, Pruritus, and Angioedemas at the End of the Study
• Standardized (With Respect to Length of Time) Area Under the Curve (AUC) for the Urticaria Activity Score (UAS) From Baseline to the End of the Study (Week 24)
• Use of Concomitant and Rescue Medications
• Change in the Dermatology Life Quality Index (DLQI) Score From Baseline to the End of the Study (Week 24)
• Change in the Skindex Score From Baseline to the End of the Study (Week 24)
• Change in Chronic Urticaria Quality of Life (CU-Q2oL) Scores From Baseline to the End of the Study (Week 24)
• Patient's Global Assessment of Their Chronic Urticaria Symptoms
• Investigator's Global Assessment of the Patient's Chronic Urticaria Symptoms

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous, and the registry reports a mean and standard deviation for each arm. The mean is the arithmetic average of participants’ change scores. The standard deviation describes how dispersed those scores are around the mean. General statistical context: when participant-level observations are available, a mean comparison estimates the difference between group averages, while the standard deviation helps describe variability within each group. The registry record does not provide participant-level data, so the displayed comparison uses posted summary statistics.

What does the mean difference represent?

The mean difference is calculated as the mean change in the omalizumab group minus the mean change in the placebo group. The posted values are -17.8 and -5.8, and the reported difference is -12.0. This contrast is on the UAS7 change scale. Since a negative change indicates improvement, a negative between-group difference means the mean change was more negative in the omalizumab arm than in the placebo arm. It is an average contrast, not an individual-level treatment effect for every participant.

The comparison is an unadjusted recalculation from the posted group summaries. “Unadjusted” means it does not incorporate covariate adjustment or other model-based corrections. The registry record does not report a sponsor analysis or a detailed model specification for this endpoint. The unadjusted calculation should not be taken to imply that the study’s original analysis used the same method.

How should the p-value be understood?

The unadjusted p-value is <0.001. General statistical context: a p-value evaluates how unusual the observed data, or data more extreme, would be under a null hypothesis and the assumptions of the statistical test. A small p-value is not the probability that the null hypothesis is correct, nor does it measure the size or importance of the estimated difference. Interpretation also depends on the analysis plan, including whether and how multiple outcomes were considered. That plan is not reported in the registry record.

The p-value is unadjusted, so it does not account for a multiplicity adjustment across the primary and secondary outcomes. The registry lists multiple secondary outcomes, but does not report a multiplicity procedure or a full set of secondary analyses. Therefore, the p-value should be interpreted as a result for this comparison rather than as a family-wise assessment across every outcome.

Why use a confidence interval as well?

A confidence interval conveys a range of values compatible with the observed data under the calculation’s assumptions. The recalculated unadjusted 95% confidence interval for the primary mean difference is -18.24 to -5.762. It gives information about both the direction and precision of the estimated contrast. A confidence interval is not a range that contains every participant’s response, and it does not represent a probability statement about a fixed parameter after the data have been observed.

The registry reports standard deviations of 10.52 and 11.52 for the primary outcome groups. These quantify spread in participant changes, while the confidence interval quantifies uncertainty in the between-group mean difference. They answer different questions. The standard deviations are not uncertainty intervals for the mean difference, and the confidence interval does not show how much participants varied individually.

What is the role of the analysis population?

The registry defines the primary intent-to-treat population as all randomized patients who received at least one dose of study drug and had at least one post-baseline assessment of the primary efficacy variable. This definition is narrower than a simple statement that every randomized participant contributes to the primary analysis, because it includes receipt of treatment and availability of a post-baseline assessment. The record does not report how many randomized patients failed to meet this definition, whether any were excluded, or how missing measurements were handled.

General statistical context: an analysis population definition specifies who contributes to an endpoint analysis. Different definitions can affect the population represented by an estimate, especially if data are missing or participants do not follow the assigned treatment. The registry record’s population definition should therefore be distinguished from assumptions about how all randomized participants were treated analytically. Further implementation details are not reported in the registry record.

Why can variability matter?

General statistical context: over-dispersion means that observations vary more than an assumed statistical model expects. Greater variability can make estimates less precise and can reduce the ability to distinguish a group contrast from random variation. For continuous outcomes, variability is summarized directly in part by the standard deviation. The registry does not report a separate over-dispersion assessment or model, and no such assessment should be inferred from the means and standard deviations alone.

There are no reported primary analyses in the registry record. Consequently, the posted result does not reveal whether the original analysis used additional covariates, a particular missing-data approach, or sensitivity analyses. Those details are not reported in the registry record. The recalculated comparison is useful for reading the posted summary statistics, but it cannot fill in undocumented protocol or analysis choices.

11. Confidence Intervals and Precision

The primary estimated mean difference is -12.0, with a recalculated unadjusted 95% confidence interval from -18.24 to -5.762. The interval remains on the negative side, consistent with the direction of the point estimate. On the endpoint’s change scale, that direction represents a larger mean reduction in UAS7 in the omalizumab group than in the placebo group.

Precision concerns how narrowly the data locate the average contrast, under the assumptions used in the calculation. It is distinct from clinical importance. The registry record does not report a threshold for a clinically meaningful difference in UAS7, so the interval cannot by itself classify the estimated magnitude as clinically important or unimportant. It also does not describe the range of individual participant changes; the group standard deviations, 10.52 and 11.52, are relevant to that separate question.

The confidence interval is an unadjusted recalculation from the posted summary statistics, not a registry-reported adjusted interval. Its interpretation depends on the calculation’s assumptions. The record does not report a detailed statistical plan, missing-data procedures, or sensitivity analyses that would show how robust the interval is to alternative analytic choices. Nor does the record report an interval adjusted for multiplicity across outcomes.

The interval is compatible with a range of negative mean differences rather than one exact underlying contrast. The point estimate is the central estimate from the posted comparison, while the confidence limits show uncertainty around it. This precision assessment should be read alongside the population definition and the study’s limited enrollment of 49, rather than as a guarantee that the same estimate would arise in another sample or population.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size figures are planning illustrations expressed as participants per arm, not total event counts. They use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set as a stated fraction of the observed effect: 100%, 75%, or 50%. The original trial’s own design assumptions and sample-size justification are not reported in the registry record.

The 80% power column gives an illustrative number of participants per arm for a design with an 80% chance of detecting the assumed effect under the stated calculation assumptions, if that effect and model were correct. The 90% power column uses a higher target chance of detection and therefore generally requires more participants per arm for the same assumed effect. For example, planning for 75% of the observed effect gives 24 participants per arm for 80% power and 32 participants per arm for 90% power.

The curve and listed planning scenarios should be read as a relationship between the assumed effect size and the required enrollment: when the effect to detect is smaller, more participants are needed. The 50% scenario illustrates this higher enrollment requirement, with 53 participants per arm for 80% power and 71 participants per arm for 90% power. These are planning illustrations based on the observed estimate, not a reconstruction of how this trial was designed. This is not observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -12.000; pooled standard deviation σ = 10.978.
2. n = 2 × (1.96 + 0.842)² × 10.978² / -12.000² = 13.1, rounded up to 14 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -12                      # observed difference in means
sigma <- 10.9780717603078                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(481676)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 14 (80% power), 18 (90% power)
 75% of observed effect: n per arm = 24 (80% power), 32 (90% power)
 50% of observed effect: n per arm = 53 (80% power), 71 (90% power)
power.t.test: 14.2 
Simulated power at n = 14 per arm: 0.791 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and multiple secondary outcomes, but a procedure for controlling multiplicity is not reported in the registry record. It is therefore unknown whether the original statistical plan treated the primary endpoint as the sole confirmatory test, defined a testing hierarchy, adjusted secondary comparisons, or interpreted those comparisons as exploratory. The unadjusted p-value for the primary comparison does not account for testing across the other outcomes.

The record does not report interim analyses or stopping rules. These should not be assumed either to have been conducted or not conducted; the relevant details are not reported in the registry record. Likewise, the original sample-size calculation and its assumptions are not reported, so the planning illustrations based on the observed effect should not be mistaken for the trial’s prospective design rationale.

The primary population is described as randomized patients who received at least one dose and had at least one post-baseline assessment of the primary efficacy variable. The record does not report the number of participants excluded from that population, the amount or pattern of missing outcome data, or the method used to address missing observations. It does not report whether participants with incomplete diaries were included, how intermittent missing values were treated, or whether sensitivity analyses were performed.

These omissions matter because analysis populations and missing-data methods define which observations contribute to an estimate and can affect both the estimate and its uncertainty. General statistical context: if missingness is related to participants’ health status or outcomes, simple analyses of available observations may not represent the full randomized group without additional assumptions. The registry record does not document the assumptions or sensitivity checks, so the degree to which missingness could influence the posted result cannot be assessed from the record.

The registry reports no analyses in its posted analysis listing. That absence limits the ability to distinguish an original sponsor analysis from the simple unadjusted recalculations based on the outcome summaries. A fuller protocol or statistical analysis plan would be needed to establish prespecification, model details, handling of missing data, and multiplicity strategy; those materials are not reported in the registry record.

15. 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: eye infection (4.5%), syncope (4.5%), angioedema (4.5%).

The registry reports serious adverse events for 0 of 27 participants in the omalizumab group and 2 of 22 participants in the placebo group. It also reports other adverse events for 19 of 27 participants in the omalizumab group and 12 of 22 participants in the placebo group. These counts describe participants with events as posted; they do not establish why an event occurred or whether it was caused by study treatment.

The registry lists Eye Infection, Syncope, and Angioedema among the serious adverse event terms, each at 4.5%. The record does not specify an arm attribution for these listed terms in the posted summary. The relationship of these terms to the group-level serious-event counts is therefore not possible to determine from the registry record alone. Death counts are not reported in the registry record.

Safety counts are descriptive and should be interpreted in light of the number of participants in each group and the study’s follow-up. A count of zero serious events in one arm does not establish that the risk is absent, and counts alone do not provide a causal comparison. The registry does not report further details about event timing, severity beyond the serious classification, or attribution to study drug.

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

The posted primary data show a difference in mean UAS7 change between the two randomized groups over the study period. The mean change was more negative in the omalizumab group, and the unadjusted recalculated comparison has a confidence interval that remains on the negative side. Under the registry’s endpoint definition, negative within-person change represents improvement in the score. This is a description of the observed group summaries and their statistical comparison, not medical advice or a conclusion about an individual participant.

The finding applies to the adult study population described in the registry: patients with moderate to severe chronic urticaria who exhibit IgE against thyroperoxidase. It pertains to the assigned omalizumab regimen and placebo comparator, and to the endpoint measured through Week 24. The registry results do not establish what would occur in populations with different characteristics, with other regimens, or over a different follow-up period.

Statistical evidence and clinical meaning are related but not interchangeable. A small unadjusted p-value addresses compatibility with a null model under test assumptions. The estimated mean difference and its confidence interval address magnitude and precision on the score scale. The registry does not report a threshold for clinically important change, so the clinical significance of the estimated difference cannot be determined from the statistical result alone.

The outcome is an average of diary-based scores. It does not indicate how many individuals improved, how many worsened, or whether responses differed across subgroups. The registry does not provide individual-level results or subgroup estimates. It also does not report enough about missing-data handling, multiplicity, or the original analysis plan to assess the influence of those analytic choices.

Finally, the secondary outcome record is incomplete: one secondary outcome has posted comparative statistics, while results for the other listed outcomes are not reported in the registry record. The safety figures are also limited to the event summaries recorded. Thus, the posted evidence supports a precise description of the primary summary comparison, but not a complete account of all outcome domains, the sponsor’s full analysis, or the reasons behind individual outcomes.

17. Why This Trial Matters Statistically

This trial is statistically informative because it reports a continuous, diary-based primary outcome in a randomized, placebo-controlled design. The endpoint combines daily ratings of wheals and pruritus over a week, while the change score compares baseline with Week 24. Those features make clear what quantity the primary group comparison addresses: an average change in a defined activity score over the study period.

The trial also illustrates why effect estimates and uncertainty should be read together. The mean difference communicates the direction and size of the average contrast on the endpoint scale, while the confidence interval conveys uncertainty around that estimate. The p-value alone would not describe either magnitude or precision. The group standard deviations add separate information about variability in participant changes.

The record also highlights limits of registry-based interpretation. The primary analysis population is defined, but details on missing data, the sponsor’s analysis, multiplicity, interim analyses, and the original enrollment rationale are not reported in the registry record. A numerical result can be read and recalculated from the posted summaries without those details, but its place in the full prespecified analysis strategy remains unclear.

Finally, the trial’s narrow population and limited enrollment should remain in view when considering how broadly its results speak. The recorded population was adults with moderate to severe chronic urticaria who exhibit IgE against thyroperoxidase, and the primary assessment ended at Week 24. The available statistics therefore teach both how to interpret an average treatment-group contrast and why study context, analysis documentation, and reporting completeness matter.

18. 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 trial enrolled 49 participants, and the posted primary outcome groups contain 27 and 22 participants. The resulting summary describes a relatively limited study population; the registry record does not provide evidence about how precisely effects would be estimated in larger or different populations. It also does not report subgroup results, so consistency across participant characteristics cannot be assessed.

The population was specific: adults with moderate to severe chronic urticaria who exhibit IgE against thyroperoxidase. The title gives an age range of 18–70 years. The results should not be generalized automatically to people outside that population. The primary endpoint covers change through Week 24, and longer-term outcomes are not reported in the registry record.

Reporting gaps constrain interpretation. The original sample-size justification, detailed statistical analysis plan, sponsor analyses, multiplicity procedure, interim analysis information, and missing-data methods are not reported in the registry record. The primary population definition requires a dose and a post-baseline assessment, but the record does not state how many randomized participants failed to meet that definition or how incomplete observations were handled. The registry lists several secondary outcomes, but most secondary results are not reported in the registry record.

The posted primary comparison is an unadjusted recalculation from group summaries. It does not incorporate undocumented covariate adjustment, missing-data assumptions, or sensitivity analyses. The record does not state a threshold for clinically meaningful UAS7 change, so the clinical importance of the estimated mean difference cannot be resolved from these statistics alone.

The safety summary is also limited. It gives counts of participants with serious and other adverse events, but further details on event timing and attribution are not reported in the registry record. Death counts are not reported. These constraints mean the safety summaries should be treated as descriptive rather than as a complete characterization of comparative safety.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Efficacy and Safety of Omalizumab in Adults (18-70 Years) With Moderate to Severe Chronic Urticaria — NCT00481676.
• Registry record last updated 2011-10-21; status last verified 2011-09.
• Results first posted 2011-10-21.
• 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.

22. Record Summary

NCT00481676 is a completed Phase 2 randomized, quadruple-masked, parallel-group, placebo-controlled study of omalizumab in adults with moderate to severe chronic urticaria who exhibit IgE against thyroperoxidase. The registry lists enrollment of 49 and a 24-week study period. The primary outcome was change in UAS7 from baseline to Week 24, with negative change indicating improvement.

The posted primary group means were -17.8 for omalizumab and -5.8 for placebo. The recalculated unadjusted mean difference was -12.0, with a 95% confidence interval of -18.24 to -5.762 and p < 0.001. One secondary outcome has comparative statistics posted; results for the other listed secondary outcomes and the sponsor’s analyses are not reported in the registry record.

The registry reports serious adverse events in 0 of 27 participants in the omalizumab group and 2 of 22 in the placebo group. Interpretation is limited by the absence of a reported original sample-size rationale, analysis plan, missing-data methods, and multiplicity strategy.