ATAREAL (Antihistamine Treatment for Allergic Rhinitis in Real Life): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for ATAREAL (Antihistamine Treatment for Allergic Rhinitis in Real Life) (NCT00160680), a randomized phase 4 study. The primary outcome is Mean Weekly Total 4 Symptom Score (T4SS) During the Treatment Period.

2. Clinical Question

The study, named ATAREAL, was a pilot clinical efficacy trial. Its central comparison is between two ways of taking the same medicine, rather than between different drugs or between treatment and no treatment. The registry describes the outcome as a mean weekly symptom score during treatment through week 24. It reports least-squares means for both groups and a sponsor-reported ANCOVA comparison of final values.

The posted results give a mean score of 2.89 for continuous treatment and 3.15 for on-demand treatment. The registry’s reported mean difference for the on-demand group relative to continuous treatment is 0.27, with a 95% confidence interval from -0.96 to 1.50 and p = 0.667. These estimates describe the observed comparison; the interval includes values on either side of zero, so the results do not precisely establish the direction or size of a difference.

The clinical question should therefore be read as a comparison of symptom-score measurements under the two assigned regimens. The registry record does not report a threshold for a clinically important score difference, so the clinical importance of any particular numerical difference is not established by this record.

3. Trial Design

ATAREAL is recorded as a phase 4, randomized, parallel-group trial with no masking. It was conducted at one center, as indicated by the official title, and is described as a pilot study. The registry lists an enrollment of 62 and marks the study as completed. The record gives the study start as 2005-03-01 and primary completion as 2006-06-01.

Both groups received levocetirizine. In the continuous-treatment group, the regimen was 5 mg orally once a day. In the on-demand group, the same 5 mg dose was taken whenever needed. The planned treatment period is described as six months, and the primary outcome timeframe runs through week 24. Because masking was recorded as none, the trial was open label; the registry does not describe a blinded outcome assessment.

The primary outcome was the mean weekly Total 4 Symptom Score during treatment. The registry states that only patients with a valid mean weekly score during the treatment period were included in that analysis. Its reported group results list 29 for each arm. The record does not give the method used to generate the random allocation sequence, details of allocation concealment, or a fuller account of the analysis population beyond the valid-score criterion.

The title and registry description identify the study as a pilot, but the registry record does not report the original sample-size justification or the assumptions used to choose the enrollment target. It also does not report whether interim analyses were planned or conducted. Those omissions matter when interpreting the precision of the results: the posted group estimates can be described, but the record does not establish that the study was designed to distinguish a particular clinically important difference.

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: Participant Flow refers to the Randomized Set.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Only patients with a valid mean weekly T4SS during the treatment period were included in the analysis.

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: Baseline Characteristics refer to the Intention-to-Treat Population.

6. Primary Endpoint

The registry lists the primary outcome as Mean Weekly Total 4 Symptom Score (T4SS) During the Treatment Period, measured over During the treatment period until week 24.

The primary endpoint is the mean weekly Total 4 Symptom Score during the treatment period, through week 24. The score adds ratings for sneezing, rhinorrhea, nasal pruritus, and ocular pruritus. Each symptom is assessed retrospectively over the past 24 hours on a scale from 0 to 3: 0 means absent, 1 mild, 2 moderate, and 3 severe. The total ranges from 0 to 12, with higher scores associated with greater disease severity.

A combined score offers a way to represent several symptoms in one continuous outcome. Averaging the weekly total over the treatment period describes symptom burden across the period rather than relying on a single symptom or one isolated assessment. It also allows a direct comparison of group means, which is the form of estimate reported for this endpoint.

The registry reports least-squares means, a model-based way of estimating group means, and standard errors as the measure of dispersion. The reported population is restricted to patients with a valid mean weekly score during treatment. The registry record does not describe additional details of how weekly observations were combined, how missing weekly scores were handled, or whether the endpoint was selected because of a particular validated threshold. It also does not report a threshold for a clinically important change. Thus the score’s direction is clear, but the clinical meaning of a given difference cannot be determined from this record alone.

7. Results Posted in the Registry

• On Demand Treatment (ODT): mean 3.15 versus 2.89 on control; difference 0.26 (95% CI -0.95 to 1.47), standardized effect d = 0.11; z-test p = 0.673.

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.

Mean Monthly Total 4 Symptom Score (T4SS) for Month 1 of the Treatment Period

• 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 errors.
• Result:
  • On Demand Treatment (ODT): mean 3.83 versus 4.55 on control; difference -0.72 (95% CI -2.41 to 0.97), standardized effect d = -0.22; z-test p = 0.404.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between On Demand Treatment (ODT) and the control. The interval gives the range of effects that remain compatible with the data.

Mean Monthly Total 4 Symptom Score (T4SS) for Month 2 of the Treatment Period

• 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 errors.
• Result:
  • On Demand Treatment (ODT): mean 3.14 versus 4.04 on control; difference -0.90 (95% CI -2.65 to 0.85), standardized effect d = -0.28; z-test p = 0.312.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between On Demand Treatment (ODT) and the control. The interval gives the range of effects that remain compatible with the data.

Mean Monthly Total 4 Symptom Score (T4SS) for Month 3 of the Treatment Period

• 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 errors.
• Result:
  • On Demand Treatment (ODT): mean 2.58 versus 2.98 on control; difference -0.40 (95% CI -1.80 to 1.00), standardized effect d = -0.16; z-test p = 0.575.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between On Demand Treatment (ODT) and the control. The interval gives the range of effects that remain compatible with the data.

The registry posts monthly Total 4 Symptom Score outcomes for the early months of treatment, as well as other secondary symptom outcomes. Across the monthly comparisons with posted values, the directions and magnitudes are not uniform: some estimates are lower for on-demand treatment, while the primary mean difference is higher for that group. The monthly estimates are uncertain, with their posted intervals including zero. Overall, the secondary results do not form a clear, consistent pattern that materially changes the interpretation of the primary comparison.

Secondary outcomes can help describe how measurements vary over time and across symptoms. They may suggest questions for later research, but they should not be treated as independent confirmation of the primary result. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting the many outcomes. When many comparisons are considered, the chance of observing apparently notable differences by chance can increase. Unadjusted secondary p-values therefore carry less weight than a prespecified primary analysis, especially when the number and handling of comparisons are not fully explained.

The secondary results should be read as exploratory context alongside the primary estimate, not as a basis for selecting whichever month or symptom appears most favorable. The registry record does not report whether all planned secondary outcomes were posted or whether analyses were prespecified in a detailed statistical analysis plan. Without that information, the completeness and confirmatory status of the secondary analysis cannot be determined.

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

• Mean Monthly Total 4 Symptom Score (T4SS) for Month 1 of the Treatment Period
• Mean Monthly Total 4 Symptom Score (T4SS) for Month 2 of the Treatment Period
• Mean Monthly Total 4 Symptom Score (T4SS) for Month 3 of the Treatment Period
• Mean Monthly Total 4 Symptom Score (T4SS) for Month 4 of the Treatment Period
• Mean Monthly Total 4 Symptom Score (T4SS) for Month 5 of the Treatment Period
• Mean Monthly Total 4 Symptom Score (T4SS) for Month 6 of the Treatment Period
• Mean Weekly Individual Symptoms Scores During the Treatment Period
• Mean Monthly Individual Symptoms Scores During Month 1 of the Treatment Period

9. Statistical Interpretation

10. Statistical Methods Explained

For a continuous endpoint, a group mean describes the average observed score in that group. The posted primary values are least-squares means rather than simple raw averages. In general, least-squares means are model-based group estimates; they can account for terms included in the fitted model. The registry identifies ANCOVA for its sponsor-reported primary comparison, but the full model specification and any covariates are not reported in the registry record.

What does the mean difference represent?

The reported mean difference is expressed as on-demand treatment relative to continuous treatment. A positive estimate therefore points toward a higher score in the on-demand group, while a negative estimate would point toward a lower score in that group. Since higher Total 4 Symptom Scores are associated with greater disease severity, the sign indicates the direction of the score contrast, not by itself its clinical importance. The posted ANCOVA estimate is 0.27. The registry’s comparison does not establish that this is a clinically meaningful difference.

What does ANCOVA contribute?

In general, analysis of covariance (ANCOVA) compares groups using a statistical model that can adjust for specified covariates. Such adjustment may improve precision or account for baseline differences, depending on the design and model. The registry reports an ANCOVA analysis of final values, but it does not identify the covariates or provide enough detail to reproduce that model. The recalculated comparison is a simple, unadjusted calculation from the posted group summaries and should not be mistaken for the sponsor’s ANCOVA.

How should standard errors be understood?

A standard error describes the uncertainty in an estimated mean, rather than the spread of individual patients’ scores. The primary group results report standard errors of 0.43 and 0.44. In general, standard errors are used to assess how precisely an estimate is determined under the analysis model. They are not the same as standard deviations, which describe variability among individual measurements. The registry does not provide the underlying individual-level data, so the posted summary statistics do not allow a full independent reconstruction of the trial analysis.

What does a confidence interval tell the reader?

In general, a confidence interval is a range of effect estimates compatible with the observed data and the assumptions of the statistical procedure. The primary ANCOVA comparison reports a 95% confidence interval from -0.96 to 1.50. Because this range includes zero and values on both sides of zero, it indicates uncertainty about the direction and magnitude of the mean-score contrast. It does not mean that every value in the interval is equally likely, or that the true effect has a 95% probability of falling within this particular interval.

What role does the p-value play?

A p-value assesses compatibility between the data and a null hypothesis under a specified statistical model. The sponsor’s reported p-value is 0.667. A large p-value is not proof that groups are identical and does not measure the probability that the null hypothesis is true. Interpretation should consider the estimated difference and its confidence interval as well as the p-value. In this trial, the interval is wide relative to the point estimate, which is an important part of the uncertainty.

Why can over-dispersion matter?

In general, over-dispersion occurs when the observed variability is greater than a model assumes. If a method assumes less variability than is present, its standard errors can be too small and its confidence intervals too narrow. Conversely, a method that accounts for excess variability may produce more cautious uncertainty estimates. This concept is relevant to statistical modeling broadly, but the registry does not report an over-dispersion assessment for this continuous symptom-score analysis. The score’s observed standard errors and the sponsor’s ANCOVA results should be interpreted as posted, without assuming that an unreported diagnostic was performed.

What can the recalculation check?

The simple recalculation uses the posted group means and summary dispersion to estimate an unadjusted comparison. It gives a mean difference of 0.26 and p = 0.673. Such a check can help readers see the rough scale of the group contrast, but it cannot recreate an adjusted analysis from aggregate summaries. It also cannot account for unreported modeling choices, participant-level patterns, or missing-data procedures. The registry’s sponsor-reported ANCOVA remains the primary reported analysis.

11. Confidence Intervals and Precision

The primary reported confidence interval is 95% and extends from -0.96 to 1.50 for the mean difference in final values. The interval includes zero, which corresponds to no mean difference, and includes estimates in both directions. Its width indicates that the trial’s estimate is not precise enough to settle the direction or magnitude of the contrast. The point estimate of 0.27 is only one value within a broader range of estimates compatible with the analysis.

Precision and statistical significance are related but not interchangeable. A p-value of 0.667 does not show that the effect is absent; it reflects the observed data under the reported analysis. The interval makes the uncertainty more interpretable by displaying a range rather than only a test statistic. In this case, it does not rule out a negative mean difference or a positive one. The record does not state what range of score differences would be clinically important, so the interval cannot be translated into a judgment about clinical relevance.

The sample was described as a pilot, and the group results list 29 for each arm. The record does not report the original sample-size calculation or a target effect the study was designed to detect. Consequently, the observed imprecision should not be interpreted as evidence that a clinically important difference is impossible. Nor does the interval demonstrate equivalence: the registry does not report an equivalence margin or a non-inferiority margin.

The sponsor’s adjusted interval and the unadjusted recalculation are based on different approaches. For the primary result, the sponsor-reported ANCOVA interval is the appropriate reported interval to emphasize. A recalculated interval from summary values would not replace the sponsor’s model-based result, particularly because the full model details are not reported in the registry record.

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 planning figures are participants per arm, not a combined total. They are illustrations based on the observed effect, not the trial’s original design calculation. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The calculations consider detecting the full observed effect, 75% of the observed effect, or 50% of the observed effect. The registry record does not report the original design assumptions or sample-size justification.

The 80% power column describes the number of participants per arm that the planning calculation estimates would be needed to have an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column uses a higher chance of detection and therefore gives a larger planning requirement for the same effect. These are design illustrations, not observed power.

Smaller effects are harder to distinguish from random variation, so the planning figures increase when the effect to detect is reduced. For example, planning for 75% of the observed effect requires more participants per arm than planning for the full observed effect; planning for 50% requires still more. This pattern is a general feature of power calculations, not a finding about what would happen in a future study. The observed effect in a pilot study can itself be uncertain, so these values should be read as scenarios rather than as a definitive enrollment recommendation.

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 = 0.260; pooled standard deviation σ = 2.343.
2. n = 2 × (1.96 + 0.842)² × 2.343² / 0.260² = 1,274.5, rounded up to 1,275 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 <- 0.26                      # observed difference in means
sigma <- 2.34270143210781                     # 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(160680)
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 = 1,275 (80% power), 1,707 (90% power)
 75% of observed effect: n per arm = 2,266 (80% power), 3,034 (90% power)
 50% of observed effect: n per arm = 5,098 (80% power), 6,825 (90% power)
power.t.test: 1275.4 
Simulated power at n = 1,275 per arm: 0.802 (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. Analyses Reported by the Sponsor

The sponsor’s own primary analysis is an ANCOVA comparison of final values. It reports a mean difference of 0.27, a 95% confidence interval from -0.96 to 1.50, and p = 0.667. This is the analysis to prioritize when reporting the registry’s primary result.

A simple recalculation from the posted summary statistics gives a mean difference of 0.26 and an unadjusted p-value of 0.673. The recalculation is not a reproduction of ANCOVA: it does not have access to the full model specification or participant-level data, and it does not represent the same adjusted analysis. The close numerical values are broadly consistent, but the sponsor’s analysis takes precedence because it is the registry’s reported analysis.

The difference between the approaches should be described as a distinction in method, not as a contradiction. The registry does not report enough detail to reconstruct all aspects of the ANCOVA, including any covariates. The unadjusted calculation is therefore best treated as a check on the aggregate summary, not as a replacement for the sponsor’s inferential result.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists numerous secondary outcomes, including monthly total symptom scores and individual symptom scores. It reports 14 outcome measures and 1 analysis for the primary outcome. The record does not explain how multiplicity was addressed across the full set of outcomes, whether any hierarchy was prespecified, or whether p-values for secondary comparisons were adjusted. When many outcomes or time points are tested, chance findings become more likely; this general concern makes unadjusted secondary results less conclusive.

The primary outcome population is described as patients with a valid mean weekly Total 4 Symptom Score during the treatment period. That criterion clarifies who was included in the primary analysis, but it does not explain how patients without a valid score were handled. The registry record does not report the amount or pattern of missing outcome data, the reasons for missingness, or the method used to address missing weekly measurements. It also does not state whether sensitivity analyses were conducted to assess the effect of missing data.

The record does not report whether the primary analysis followed an intention-to-treat principle, whether participants were analyzed according to randomized assignment in all circumstances, or how protocol deviations were handled. The reported valid-score criterion should therefore not be expanded into assumptions about the full analysis population.

Further details about randomization methods, allocation concealment, covariate selection in ANCOVA, and the statistical analysis plan are not reported in the registry record. These omissions limit assessment of prespecification and reproducibility. They do not invalidate the posted estimates, but they mean that the reader cannot independently verify all analytical decisions or determine whether the reported analyses followed a complete prespecified plan.

16. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse event figures separately for the continuous and on-demand groups. No serious adverse events were reported among the 30 at risk in continuous treatment, and none were reported among the 32 at risk in on-demand treatment. The record also lists 0 deaths for each group.

For other adverse events, the registry reports 4 affected among 30 at risk in the continuous-treatment group and 10 affected among 32 at risk in the on-demand group. These are descriptive counts in the posted safety record. They should not be taken as a reliable estimate of a treatment difference without details about event definitions, observation time, ascertainment, and the analysis used. The registry record does not provide further detail on the types of other adverse events in these figures.

Zero reported serious events does not establish that serious events cannot occur; it describes what was recorded in this trial. The study is identified as a pilot and its safety counts are limited in scope. The registry record does not report a formal comparative safety analysis or enough information to interpret the counts as evidence that one regimen is safer.

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

The results show that the primary mean weekly symptom scores were 2.89 for continuous treatment and 3.15 for on-demand treatment. In the sponsor’s ANCOVA analysis, the estimated mean difference in final values was 0.27, with a 95% confidence interval from -0.96 to 1.50 and p = 0.667. The interval covers estimates in both directions, so the posted evidence does not precisely establish the direction or size of a difference between regimens.

This result does not show that the regimens are equivalent. Equivalence requires a prespecified margin defining how much difference would be considered acceptably small, together with an analysis designed to assess that margin. The registry record does not report such a margin. The result also does not prove that the regimens differ, or establish that any score difference is clinically important. No threshold for a clinically important difference is reported.

The findings apply to the trial’s reported outcome and analyzed population: patients with a valid mean weekly score during treatment. They do not directly answer questions about symptoms outside the measurement period, outcomes not posted in the record, or populations not described by the trial. The design was randomized and open label, and the trial is identified as a pilot. Those features are relevant when considering the scope and strength of the evidence.

The primary result is best understood as an uncertain estimate rather than a definitive verdict. The reported ANCOVA is the sponsor’s analysis; the simple recalculation is an unadjusted check and does not replace it. The secondary outcomes offer additional descriptive context, but their unadjusted nature and the unreported multiplicity approach limit how strongly they can support conclusions.

18. Why This Trial Matters Statistically

This trial illustrates why a point estimate should not be read in isolation. The posted group means and mean difference provide a central estimate, while the confidence interval shows that the estimate remains uncertain. Here, the interval includes values on both sides of zero, so a reader should avoid turning the direction of the point estimate into a definitive claim about the comparative effect.

It also demonstrates the distinction between a sponsor-reported model-based analysis and a simple recalculation from summary statistics. An unadjusted calculation can be a useful numerical check, but it cannot reproduce an ANCOVA when the model specification and participant-level data are unavailable. Reporting both approaches transparently helps keep the role of each clear: the registry’s ANCOVA is the primary reported result, and the recalculation is supplementary.

Finally, the pilot designation and the absence of reported original design assumptions make precision especially important to discuss. Planning illustrations based on the observed effect can show how requirements change under stated assumptions, but they are not evidence of observed power and cannot establish what the trial was originally designed to detect. The record also highlights the importance of reporting missing-data procedures, multiplicity plans, and analysis populations so readers can judge how well results can be reproduced and how much weight to give secondary findings.

19. 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 is described as a pilot and as open label, with no masking. Because patients and investigators were not masked according to the registry, expectations or knowledge of the assigned regimen could affect symptom reporting or other aspects of assessment. The record does not state whether outcome assessment was otherwise protected from knowledge of treatment assignment.

The registry describes the primary analysis population as patients with a valid mean weekly score during treatment, but does not report how missing scores were handled or how many measurements were missing. It also does not provide a full account of the analysis population, protocol deviations, or sensitivity analyses. These omissions make it difficult to assess how robust the estimate is to incomplete outcome data.

The sponsor’s ANCOVA is reported without the complete model specification. The registry record does not identify covariates or provide enough information to reproduce that adjusted analysis. The unadjusted recalculation is therefore limited to the posted group summaries and cannot resolve questions about modeling choices.

The record does not report the original sample-size justification, a clinically important score difference, or an equivalence or non-inferiority margin. Thus, the results cannot establish that the study had adequate precision for a particular clinical threshold, nor can the observed p-value be used to conclude equivalence. The registry also does not report a multiplicity approach for the many secondary outcomes, limiting their confirmatory interpretation.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: ATAREAL (Antihistamine Treatment for Allergic Rhinitis in Real Life) — NCT00160680.
• Registry record last updated 2023-08-31; status last verified 2023-08.
• Results first posted 2019-01-22.
• 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.

23. Record Summary

ATAREAL was a completed, phase 4, randomized, open-label, parallel-group pilot trial comparing continuous and on-demand levocetirizine in adults with persistent allergic rhinitis. The treatment period was six months, and the primary endpoint was the mean weekly Total 4 Symptom Score through week 24.

The sponsor-reported ANCOVA estimated a mean difference in final values of 0.27 for on-demand relative to continuous treatment, with a 95% confidence interval from -0.96 to 1.50 and p = 0.667. A simple unadjusted recalculation gives a mean difference of 0.26 and p = 0.673. The sponsor’s analysis is the primary reported result.

The interval is compatible with differences in either direction, and the registry does not report a clinically important difference or equivalence margin. Missing-data procedures, detailed model specification, original sample-size assumptions, and multiplicity handling are not reported in the registry record. The secondary and safety results should therefore be read as descriptive context rather than as definitive evidence of comparative benefit or safety.