Efficacy and Safety of a Sore Throat Lozenge Containing Lidocaine and Cetylpyridinium Chloride in Patients With Sore Throat Due to a Common Cold.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of a Sore Throat Lozenge Containing Lidocaine and Cetylpyridinium Chloride in Patients With Sore Throat Due to a Common Cold. (NCT01265446), a randomized phase 3 study. The primary outcome is Change From Baseline Sore Throat Pain Intensity.

2. Clinical Question

The outcome was measured on a 100 mm visual analogue scale, with 0 mm defined as no pain and 100 mm as the worst possible pain. A negative change represents a lower score at follow-up than at baseline. The posted arm means are -27.4 mm for the lidocaine 8 mg plus CPC 2 mg lozenge and -26.9 mm for the lidocaine 1 mg plus CPC 2 mg lozenge. Each arm has a 95% confidence interval. Those separate estimates describe change within each arm; they do not, by themselves, quantify the difference between treatments.

The study also lists change in pain intensity up to 240 mn post-dose as a secondary outcome. The registry record does not report estimates for that secondary outcome. It also does not report a conclusion about whether the treatments differ on the primary question.

3. Trial Design

This was a randomized, parallel-group, single-dose Phase 3 study. The registry lists an enrollment of 250 and identifies the study as completed. It lists Novartis as sponsor. The registry dates are 2010-12 for study start and 2011-04 for primary completion.

The two groups received different lozenge formulations: lidocaine 8 mg plus CPC 2 mg or lidocaine 1 mg plus CPC 2 mg. Each arm description specifies one single dose. The official title describes the study as double-blind, while the registry masking category is quadruple. The registry record does not explain the masking procedures or how the two descriptions relate.

For the primary outcome, the posted results include 125 participants in each arm. The endpoint is mean change from baseline in pain intensity, measured at baseline and two hours after dosing, among the intent-to-treat population. The registry reports an arm mean and a 95% confidence interval for each group. It does not report a direct estimate comparing the arm means, a test statistic, or a p-value for this outcome.

The record lists one secondary outcome: change from baseline in sore-throat pain intensity up to 240 mn post-dose. It does not report secondary outcome results. Although the study is marked completed, completion status alone does not establish that every planned result or analysis is included in the registry record. Further details of the protocol, allocation procedure, analysis plan, and conduct 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

Analysis population for the primary outcome, as defined in the registry: Intent to treat

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline Sore Throat Pain Intensity, measured over Baseline and 2 hours post-dose.

The primary endpoint is change from baseline in sore-throat pain intensity, measured in mm on a 100 mm visual analogue scale. The record defines the scale endpoints as no pain at 0 mm and the worst possible pain at 100 mm. The endpoint uses a mean, so each arm’s result represents the average change in its recorded scores rather than the experience of every participant.

The measurement was taken at baseline and two hours post-dose. Change scores put follow-up values in the context of baseline pain: a negative value means the recorded score was lower at follow-up than at baseline. The reported mean changes are -27.4 mm for the lidocaine 8 mg plus CPC 2 mg arm and -26.9 mm for the lidocaine 1 mg plus CPC 2 mg arm. The registry gives a 95% confidence interval for each mean.

As a general statistical point, a continuous pain score can preserve differences across a scale rather than reducing experience to a yes-or-no outcome. A mean is a compact measure of the group’s average change, but it does not show how scores vary among participants or whether individual changes were alike. The registry record does not report the distribution of scores, a standard deviation, or a responder definition. The endpoint therefore describes average change at the stated time, not the full pattern of pain responses over time.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean change represent?

The primary outcome is continuous: pain intensity is recorded in mm on a visual analogue scale. A mean change summarizes the average difference between baseline and the two-hour measurement within an arm. The negative means, -27.4 mm and -26.9 mm, indicate that the average follow-up score was lower than the average baseline score in each group, according to the stated change measure. The mean does not imply that every participant had a lower score, and it does not describe the spread of individual changes.

The registry identifies the primary population as intent to treat. That label indicates the population designation attached to the posted result, but the record does not report the precise analysis-population rules, how missing measurements were handled, or whether all randomized participants contributed to the endpoint estimate.

How should the confidence intervals be read?

Each arm’s estimate is accompanied by a 95% confidence interval: -31.0 to -23.8 mm for the lidocaine 8 mg plus CPC 2 mg arm, and -30.5 to -23.3 mm for the lidocaine 1 mg plus CPC 2 mg arm. In general, a confidence interval expresses the statistical uncertainty around an estimate under the model and assumptions used to calculate it. It is not a range containing every participant’s change, and it is not a guarantee about an individual response. The interval’s width reflects precision: narrower intervals indicate greater precision than wider intervals, all else equal.

These intervals are for separate arm means. They are not a confidence interval for the contrast between arms. Comparing their endpoints by eye is not a replacement for a direct contrast, since the uncertainty of a contrast depends on the analysis and on the relationship between the observations. The registry record does not report the method used to calculate the confidence intervals or a direct comparative interval.

Why is a direct comparison important?

Randomized parallel-group trials are generally designed to compare outcomes between assigned groups. For this primary endpoint, a direct estimate would quantify the difference in mean change between the two formulations, with uncertainty around that contrast. A test, if prespecified and reported, could address a statistical hypothesis about that contrast. The registry record does not report a comparative estimate, a test statistic, a p-value, or the statistical model for such an analysis. The arm-level summaries alone cannot establish the result of an unreported comparison.

As a general point, change-from-baseline outcomes can be analysed in different ways, such as by comparing change scores or by modelling follow-up scores while accounting for baseline. These approaches can have different precision and assumptions. The record does not say which approach was specified or used for a between-arm analysis, so neither should be attributed to this trial.

What can sample-size illustrations tell a reader?

The posted sample-size illustrations are planning scenarios based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. They consider detecting a stated fraction of the observed effect. Such calculations describe hypothetical design requirements under those assumptions; they are not the trial’s observed power and do not establish that the trial was planned using those assumptions. The registry record does not report the original sample-size justification, target effect, or planning calculation.

As a general statistical concept, power calculations depend on an effect to detect, variability, the chosen significance level, and the allocation and analysis assumptions. When the target effect is based on an observed estimate, the illustration is retrospective and can be sensitive to uncertainty in that estimate. It should not be interpreted as evidence that a particular effect was reliably detectable in this completed study. The registry record does not report the variability measure used in the original design.

What is not established by the posted analyses?

The registry lists no analysis records for the outcome data. It does post arm-level mean changes and confidence intervals, but does not identify a comparative model, adjustment strategy, handling of multiplicity, or missing-data method. These details are important to interpreting a treatment contrast and its precision. They are not reported in the registry record and should not be inferred from the arm summaries.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary outcome of change from baseline in sore-throat pain intensity at two hours and one secondary outcome of change up to 240 mn post-dose. It does not report results for the secondary outcome. The record also does not report whether the trial tested additional outcomes, which analyses were confirmatory, or whether any adjustment for multiple comparisons was planned or used. A multiplicity strategy is therefore not reported in the registry record.

Multiplicity matters in general when several hypotheses are tested: interpreting each test as if it were the only one can increase the chance of at least one false-positive finding across a family of tests. Whether that issue arose in this study, and how it was addressed, cannot be established from the posted record. No comparative p-value is reported for the primary endpoint, so there is no posted primary test to interpret in relation to other tests.

The primary endpoint population is labelled intent to treat, and the primary arm results list 125 participants per arm. The record does not report how the intent-to-treat population was defined, whether endpoint observations were missing, how any missing data were handled, or whether a sensitivity analysis was conducted. It also does not report reasons for any missing measurements. These omissions limit assessment of whether the posted estimates represent the intended population and how dependent they may be on assumptions about missing outcomes.

The record does not report interim analyses or stopping rules. It also does not report a statistical analysis plan. Those features should be treated as unknown rather than assumed absent. The posted results support description of the two arm means and their confidence intervals, but do not supply enough detail to reconstruct the planned multiplicity, missing-data, or comparative-analysis procedures.

11. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: tendon rupture (0.8%).

The registry reports serious adverse events affecting 1 participant in the lidocaine 8 mg plus CPC 2 mg arm and 0 participants in the lidocaine 1 mg plus CPC 2 mg arm. The listed number at risk for this measure is 125 in each arm. These are event counts in the registry record, not a comparative safety analysis. The record does not report a statistical comparison or uncertainty interval for the difference between these counts.

The registry also lists 10 participants with other adverse events in the lidocaine 8 mg plus CPC 2 mg arm and 9 in the lidocaine 1 mg plus CPC 2 mg arm, with 125 at risk in each group. The category is labelled other adverse events, and should not be combined with the serious-event counts unless the record defines how the categories relate. That definition is not reported in the registry record.

Tendon rupture appears among the top serious adverse event terms, with 0.8% listed. The record does not identify an arm for that term or explain its relation to the arm-level serious-event counts. Death counts are not reported in the registry record. Rare-event counts can be imprecise, and these figures alone do not establish whether an event was caused by treatment or whether risks differed between groups.

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

The results describe mean pain-score changes at two hours after a single dose in two randomized arms. The reported mean changes are -27.4 mm for lidocaine 8 mg plus CPC 2 mg and -26.9 mm for lidocaine 1 mg plus CPC 2 mg. Each estimate has a 95% confidence interval. This supports a description of the posted average change within each arm and the uncertainty around those arm means.

The record does not report the direct difference between the arms, its confidence interval, or a test of that difference. Therefore, the separate mean changes do not establish whether one formulation produced a greater average change than the other. Nor do they establish equivalence: that requires an appropriate design, a defined margin, and a comparative analysis, none of which is reported in the registry record.

The findings are limited to the measured endpoint and time. The primary measure is pain intensity on a visual analogue scale at two hours; the listed secondary outcome extends to 240 mn post-dose, but its results are not reported. The posted endpoint does not describe all possible effects or the full course of symptoms.

The registry identifies the primary result population as intent to treat, but does not explain its implementation or report missing-data handling. It also does not provide the protocol-level statistical plan or analysis records. These gaps limit the ability to assess how the results were selected, analysed, or affected by unobserved measurements.

Accordingly, the record offers arm-specific estimates but not the comparative result needed to answer the central question about the difference between the two lozenges. The safety counts are also descriptive and do not establish causation or comparative risk. No treatment recommendation follows from these posted summaries alone.

13. Why This Trial Matters Statistically

This trial illustrates a common distinction in clinical-trial reporting: an outcome can be reported separately for each randomized group without reporting the direct contrast that addresses the comparative question. For the primary endpoint, the record gives a mean change and confidence interval for each arm. Those estimates are useful descriptions, but the central randomized comparison is not included in the posted results.

The distinction matters because within-arm change and between-arm difference answer different questions. A mean change describes how scores shifted from baseline within a group. A contrast asks whether the average shift differed between the groups. Randomization supports a comparative interpretation when the analysis and results are reported, but arm-level summaries alone do not supply the missing contrast or its precision.

The confidence intervals also demonstrate why uncertainty should be presented with estimates rather than relying on point values alone. Yet intervals around separate means should not be mistaken for an interval around the treatment difference. The record does not report that comparative uncertainty, so the primary inference cannot be recovered by treating the two arm intervals as if they were a formal test.

The trial also underscores the importance of transparent reporting of analysis populations, missing-data methods, multiplicity procedures, and prespecified statistical methods. The registry identifies an intent-to-treat population, but does not give the operational details needed to assess implementation. The primary comparative analysis and secondary outcome results are not reported in the record.

Finally, the planning illustrations are hypothetical calculations based on the observed effect and stated assumptions. They are distinct from evidence about observed power or from the original design rationale. Keeping planning calculations, arm-level descriptions, and confirmatory comparative results conceptually separate helps avoid stronger conclusions than the record supports.

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.

The main limitation for interpretation is that the registry record does not report a direct between-arm estimate for the primary endpoint. It provides arm means and confidence intervals, but no comparative confidence interval, test statistic, or p-value. The record therefore does not show the size or precision of the treatment contrast that addresses the primary question.

The record does not report a statistical analysis plan, details of the confidence-interval method, or the model used for any comparative analysis. It also does not report the original sample-size rationale. The planning illustrations based on the observed effect cannot fill these gaps or establish how the study was designed.

Although the primary population is identified as intent to treat, the registry record does not define the analysis set or describe missing measurements and their handling. The listed secondary outcome has no reported result. Multiplicity procedures, interim analyses, and stopping rules are not reported in the registry record.

The primary endpoint is a mean change at two hours. The record does not report individual-level distributions or a measure of spread for changes, which limits understanding of variation within each arm. It also does not report a clinically important threshold for interpreting the scale change. The posted summary therefore cannot show how the average relates to a prespecified threshold or how responses differed across participants.

Safety information is also limited to event counts and a serious-event term listing. The registry does not report a comparative safety analysis, an arm assignment for the tendon rupture term, or death counts. These limitations are specific to what is reported in the registry record and do not establish what may have been collected or analysed outside it.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Efficacy and Safety of a Sore Throat Lozenge Containing Lidocaine and Cetylpyridinium Chloride in Patients With Sore Throat Due to a Common Cold. — NCT01265446.
• Registry record last updated 2013-04-24; status last verified 2013-04.
• Results first posted 2012-07-26.
• 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.

18. Record Summary

NCT01265446 is a completed randomized, parallel-group Phase 3 study of single-dose lozenges for sore throat due to a common cold. It compares lidocaine 8 mg plus CPC 2 mg with lidocaine 1 mg plus CPC 2 mg. The primary endpoint is mean change from baseline in sore-throat pain intensity at two hours, measured on a 100 mm visual analogue scale, in the intent-to-treat population.

The posted mean changes are -27.4 mm and -26.9 mm, respectively, with a 95% confidence interval for each arm. No direct comparative estimate or primary test is reported in the registry record. A secondary outcome covering change up to 240 mn post-dose is listed without results. The record also posts arm-level adverse-event counts; further comparative safety analysis is not reported.

Details of the statistical analysis plan, missing-data handling, multiplicity procedures, and original sample-size rationale are not reported in the registry record. The posted information supports description of the arm-specific results but does not provide the comparative analysis needed to resolve the primary treatment question.