This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Comparing the Efficacy of Bricanyl M2 and Bricanyl M3 at 0.5 and 1.5 mg Dose Levels, to Allow for a Switch From Bricanyl Turbuhaler M2 to Bricanyl Turbuhaler M3 (NCT02322788), a randomized phase 3 study. The primary outcome is Provocative Concentration of Methacholine Which Produces a 20% Fall in FEV1 (PC20).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02322788 |
| Phase | Phase 3 |
| Condition | Asthma |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | Triple |
| Enrollment | 95 |
| Arms in the primary outcome | 4 |
| Lead sponsor | AstraZeneca |
| Results posted | Yes |
2. Clinical Question
Population
Participants had stable, mild to moderate asthma. The registry lists an efficacy analysis set and reports enrollment of 95; the number of participants contributing to the primary outcome is not separately described as a count of unique people.
Intervention
The study compared Bricanyl Turbuhaler M3 and M2 at dose levels labelled 0.5 mg and 1.5 mg. The arm descriptions list M3 as 0.4 mg terbutaline per inhalation and M2 as 0.5 mg per inhalation; the record does not explain how those descriptions relate to the dose-level labels.
Comparator
Each active formulation and dose was compared with the corresponding other formulation or dose in the crossover analyses. Two additional inhaler interventions are described as placebo powders, but the posted primary comparisons are active-treatment comparisons.
Primary question
Did the formulations or dose levels differ in the methacholine concentration needed to produce a 20% fall in FEV1, measured as PC20? A higher PC20 indicates that a greater methacholine concentration was needed to reach that fall, reflecting greater measured protection in this challenge test.
This was a pharmacodynamic question about a measured response to an induced bronchoconstriction challenge, rather than a question about long-term asthma control, symptoms, or exacerbations. The primary outcome was assessed across four cross-over treatments, each lasting <1 day, with 2-10 days between treatment washout periods. Because participants received treatments in a crossover design, the treatment comparisons concern responses across periods within the study, not a simple comparison of separate parallel groups. The registry record does not report the sequence allocation details, the model's handling of period or sequence effects, or a clinical threshold defining a meaningful PC20 difference.
3. Trial Design
The registry describes a randomized, Phase III, multi-site, single-dose, 4-way crossover pharmacodynamic study. It lists triple masking and also characterizes the study as double-blind and double-dummy in its official title and brief summary. These descriptions indicate efforts to mask treatment assignment, but the precise roles masked are not reported in the registry record. The study status is completed, with start listed as 2015-03 and primary completion as 2015-11.
The four treatment arms were M3 1.5 mg, M3 0.5 mg, M2 1.5 mg, and M2 0.5 mg. The listed active ingredient was terbutaline sulphate. The arm descriptions state that M2 active powder contained 0.5 mg terbutaline per inhalation and M3 active powder contained 0.4 mg per inhalation. The record does not explain the relationship between those per-inhalation descriptions and the dose-level labels. Two placebo powder interventions are also listed. The registry does not provide further details of how the double-dummy treatments were assembled.
Enrollment was 95. The primary outcome results list n=60 for each treatment arm in the efficacy analysis set. In a crossover study, an arm-level result refers to observations associated with a treatment, not necessarily a separate set of people assigned only to that arm. The registry record does not explain the difference between the enrollment figure and the arm-level analysis counts, or report participant flow and exclusions in enough detail to reconcile them.
The primary outcome was PC20, with results presented as least-squares means and 95% confidence intervals. Four mixed-model comparisons are posted: two dose comparisons within formulation and two formulation comparisons at the same labelled dose. Model specification, treatment sequence details, and the prespecified analysis plan 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.
Before assignment: Of the 95 patients enrolled 34 were screen failures mainly due to not fulfilling specific randomization criteria on stability in asthma or sensitivity to methacholine challenge; 1 was withdrawal by subject; 72 entered run in period. A total of 60 patients were randomized to the 4 single-dose treatments with terbutaline in a crossover design.
Visit 3
| Stage | M2 0.5 mg | M2 1.5 mg | M3 0.5 mg | M3 1.5 mg |
|---|---|---|---|---|
| STARTED | 15 | 15 | 14 | 16 |
| COMPLETED | 15 | 15 | 14 | 16 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
Visit 4
| Stage | M2 0.5 mg | M2 1.5 mg | M3 0.5 mg | M3 1.5 mg |
|---|---|---|---|---|
| STARTED | 15 | 14 | 16 | 15 |
| COMPLETED | 15 | 14 | 16 | 15 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
Visit 5
| Stage | M2 0.5 mg | M2 1.5 mg | M3 0.5 mg | M3 1.5 mg |
|---|---|---|---|---|
| STARTED | 16 | 15 | 15 | 14 |
| COMPLETED | 16 | 15 | 15 | 14 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
Visit 6
| Stage | M2 0.5 mg | M2 1.5 mg | M3 0.5 mg | M3 1.5 mg |
|---|---|---|---|---|
| STARTED | 14 | 16 | 15 | 15 |
| COMPLETED | 14 | 16 | 15 | 15 |
| NOT COMPLETED | 0 | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Efficacy analysis set
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: Full analysis set
| Characteristic | Unit | Overall |
|---|---|---|
| Participants analysed | 60 | |
| Age, Continuous | Years | 31.1 (SD 12.19) |
| Gender: Female | Participants | 40 |
| Gender: Male | Participants | 20 |
| Race/Ethnicity, Customized: White | Participants | 57 |
| Race/Ethnicity, Customized: Black or African American | Participants | 1 |
| Race/Ethnicity, Customized: Asian | Participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Provocative Concentration of Methacholine Which Produces a 20% Fall in FEV1 (PC20), measured over 4 cross-over treatments (<1 day each) with 2-10 days between treatment washout periods.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | mg/mL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the provocative concentration of methacholine that produces a 20% fall in FEV1, abbreviated PC20 and measured in mg/mL. FEV1 is the amount of air forcibly exhaled in the first second of a breathing test. Methacholine is used in a challenge test because it can narrow the airways; PC20 records the concentration at which the defined fall in FEV1 occurs.
PC20 is used as a pharmacodynamic measure of airway responsiveness. In this setting, a higher value means that a higher methacholine concentration was required to produce the specified fall in FEV1. It therefore captures a treatment-related response under a controlled challenge, rather than everyday symptoms or long-term clinical outcomes. The registry reports least-squares means with 95% confidence intervals, and it reports estimated mean ratios for the treatment comparisons.
The outcome was measured during four cross-over treatments lasting <1 day each, with 2-10 days between treatment washout periods. That timing makes the result specific to the single-dose challenge conditions described in the record. The registry does not report the exact timing of PC20 measurement after dosing, details of the challenge procedure, or a threshold for interpreting the size of a difference as clinically important. Accordingly, the endpoint can describe comparative pharmacodynamic response in this study, but cannot by itself describe longer-term asthma outcomes.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The arm-level least-squares mean PC20 was 17.7 mg/mL for M3 1.5 mg and 9.88 mg/mL for M3 0.5 mg. For M2, the corresponding values were 20.1 mg/mL at 1.5 mg and 10.78 mg/mL at 0.5 mg. Each arm-level result is accompanied by a 95% confidence interval. These summaries describe the fitted outcome means in the efficacy analysis set; they are not raw participant-level observations.
The mixed-model comparison of M2 1.5 mg with M2 0.5 mg reported an estimated mean ratio of 1.87, with a 95% confidence interval from 1.52 to 2.29 and p < 0.001. For M3 1.5 mg compared with M3 0.5 mg, the estimated mean ratio was 1.79, with a 95% confidence interval from 1.46 to 2.20 and p < 0.001. Both estimates point toward a higher PC20 at the higher labelled dose within the respective formulation, and both intervals exclude the no-difference ratio. The p-values indicate incompatibility with that no-difference comparison under the reported model, but do not quantify clinical importance.
At the 0.5 mg labelled dose, the comparison of M3 with M2 reported an estimated mean ratio of 0.92, with a 95% confidence interval from 0.75 to 1.13. At 1.5 mg, the M3-to-M2 comparison was 0.88, with a 95% confidence interval from 0.72 to 1.08. Both intervals include the no-difference ratio, so these estimates do not establish a difference between formulations at those dose levels. They also do not establish equivalence or non-inferiority: the registry record does not report a margin or the decision criteria for such a conclusion, and p-values are not posted for these two comparisons.
The confidence intervals express uncertainty around the estimated treatment comparisons under the stated mixed-model analysis. Their width shows that the data are compatible with a range of ratios, rather than a single exact value. Interpretation should remain specific to PC20 in this single-dose crossover study. The registry does not report a clinical importance threshold, longer-term outcome results, or enough model details to assess every assumption underlying the estimates.
9. Statistical Methods Explained
The primary outcome is continuous: PC20 can take a range of measured values rather than being only a yes-or-no event. The registry presents each arm's outcome as a least-squares mean with a 95% confidence interval. A least-squares mean is a model-based estimate of the mean response, potentially adjusted for terms included in the fitted model. Which terms were included is not reported in the registry record, so the estimates should not be described as adjusted for any particular participant or study factor.
What does the confidence interval convey?
A confidence interval represents uncertainty in an estimate under the statistical model and its assumptions. A narrower interval indicates greater precision than a wider interval, while the interval endpoints show values still reasonably compatible with the data and model. For the arm-level PC20 estimates, the registry reports 95% confidence intervals. For the treatment comparisons, it reports 95% confidence intervals around estimated mean ratios. These intervals are not a range containing a fixed proportion of individual participant results, and they do not account for unreported sources of bias or model misspecification.
How should the mean ratios be read?
A mean ratio expresses one treatment's fitted outcome relative to another treatment's fitted outcome. The direction depends on which treatment is the numerator and which is the denominator; the comparison pairs are listed in the registry in a specific order. The within-formulation dose comparisons have estimates above the no-difference ratio, while the same-dose formulation comparisons have estimates below it. For a ratio, the no-difference value is the value at which the two fitted means are equal. A confidence interval that excludes that value supports a difference under the model; an interval that includes it leaves no clear evidence of a difference from that analysis alone.
The two dose comparisons have intervals that exclude the no-difference ratio and reported p-values of p < 0.001. The two formulation comparisons have intervals that include it, and the registry does not post p-values for those comparisons. An interval including the no-difference value is not proof that the treatments are the same. Evidence of equivalence or non-inferiority requires a prespecified margin and an analysis designed to evaluate that margin. Such criteria are not reported in the registry record.
Why use a mixed model for a crossover study?
In a crossover design, treatment responses are collected across multiple treatment periods, so measurements from the same participant are related rather than independent. A mixed model can represent such dependence and estimate treatment contrasts while accounting for the model terms chosen by investigators. This is a general explanation, not a description of the exact model in this trial: the registry names mixed models analysis but does not report its covariance structure, fixed or random effects, adjustments, or diagnostic checks. The treatment sequence and period effects included in the analysis are not reported in the registry record.
Washout periods are intended to separate treatment periods, but the registry's description of 2-10 days between periods does not establish whether carryover was absent. Whether carryover was assessed, and how missing period measurements were handled, is not reported in the registry record. Those details matter because a crossover analysis relies on suitable handling of within-participant correlation and period-related influences.
What do p-values add?
A p-value summarizes how incompatible the observed data are with a specified null model, assuming the model and its assumptions are appropriate. It is not the probability that the null hypothesis is true, nor does it measure the magnitude or clinical importance of an effect. The reported p < 0.001 values accompany the two dose comparisons. The registry does not provide p-values for the formulation comparisons, so those should not be reconstructed from the confidence intervals.
There are four posted primary-outcome analyses. The registry does not state whether these comparisons were prespecified as a family, whether multiplicity adjustment was used, or which comparison was intended to be confirmatory. When multiple analyses are considered, the chance of at least one apparently notable result can be affected by the analysis strategy. The reported estimates and intervals remain useful descriptions, but the missing multiplicity plan limits interpretation of the p-values as a family of tests.
Finally, model-based estimates rely on assumptions about the outcome distribution, the relationship between observations, and the way the model represents treatment and study periods. The registry's brief method label is not enough to assess those assumptions. The posted results support a description of the fitted comparisons, while a full independent assessment would require the analysis specification and participant-level data, neither of which is reported in the registry record.
10. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| Mixed Models Analysis | Estimated mean ratio 1.87 | 1.52 to 2.29 | < 0.001 |
| Mixed Models Analysis | Estimated mean ratio 1.79 | 1.46 to 2.20 | < 0.001 |
| Mixed Models Analysis | Estimated mean ratio 0.92 | 0.75 to 1.13 | not reported |
| Mixed Models Analysis | Estimated mean ratio 0.88 | 0.72 to 1.08 | not reported |
The registry reports the sponsor's treatment comparisons as mixed models analyses with estimated mean ratios and 95% confidence intervals. The dose comparisons within M2 and within M3 have reported p-values of p < 0.001. The formulation comparisons at the same labelled dose have confidence intervals but no posted p-values. These are the results to use when describing the sponsor's own inferential analysis.
No discrepancy is flagged between the sponsor's analysis and any recalculated comparison. However, the registry record indicates that values are missing or not estimable for a two-arm recalculation of this continuous endpoint. Therefore, there is no recalculated two-arm result to set alongside the sponsor's mixed-model estimates. The arm-level least-squares means and confidence intervals do not, on their own, supply the within-participant information or model details needed to recreate a crossover comparison.
Any sample-size illustration based on an observed effect is a planning exercise, not observed power and not evidence about the design's original justification. The registry record does not report the original sample-size justification. The sponsor's fitted analysis remains the primary reported comparison, with interpretation constrained by the limited model specification and the unreported multiplicity plan.
11. Multiplicity, Missing Data and Analysis Populations
The registry posts four analyses of the primary continuous outcome: a dose comparison within M2, a dose comparison within M3, and formulation comparisons at the 0.5 mg and 1.5 mg labelled dose levels. It does not report whether these were all prespecified, which comparisons were primary for inference, or whether any multiplicity adjustment was applied. When several hypotheses are tested, an unadjusted p-value does not by itself describe the overall error rate across the family of tests. The two posted p-values should therefore be read as results for their stated comparisons, not as a complete account of the uncertainty across all analyses.
The registry provides p-values for the two dose comparisons but not for the formulation comparisons. It reports confidence intervals for all four comparisons. The missing p-values should not be inferred or calculated from those intervals. Likewise, the absence of a statistically significant result for a formulation comparison would not demonstrate equivalence or non-inferiority. The registry does not report the margins or analysis criteria needed for those conclusions.
The primary outcome population is labelled the efficacy analysis set. The registry does not report the definition of that set, participant flow by treatment period, reasons for exclusions, or details of missing outcome measurements. It also does not say how missing data were handled in the mixed model or whether sensitivity analyses were performed. Those omissions limit assessment of whether the analysis population and handling of incomplete records could affect the reported estimates.
Enrollment is reported as 95, whereas n=60 appears for each treatment arm's primary-outcome result. Since the trial used a crossover design, these arm-level counts should not be added to infer a number of unique participants. The registry does not explain the relationship between enrollment and the treatment-level efficacy counts. The sample-size justification and any interim analyses are not reported in the registry record.
12. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| M2 0.5 mg | 0 | 60 | 0.0% |
| M2 1.5 mg | 0 | 60 | 0.0% |
| M3 0.5 mg | 0 | 60 | 0.0% |
| M3 1.5 mg | 0 | 60 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| M2 0.5 mg | 12 of 60 |
| M2 1.5 mg | 10 of 60 |
| M3 0.5 mg | 7 of 60 |
| M3 1.5 mg | 13 of 60 |
Most frequent non-serious adverse event terms
| Event term | Organ system | M2 0.5 mg | M2 1.5 mg | M3 0.5 mg | M3 1.5 mg |
|---|---|---|---|---|---|
| Dysgeusia | Nervous system disorders | 6 of 60 | 6 of 60 | 5 of 60 | 7 of 60 |
| Tremor | Nervous system disorders | 2 of 60 | 3 of 60 | 1 of 60 | 5 of 60 |
| Palpitations | Cardiac disorders | 0 of 60 | 1 of 60 | 1 of 60 | 2 of 60 |
| Nasopharyngitis | Infections and infestations | 2 of 60 | 0 of 60 | 0 of 60 | 1 of 60 |
| Headache | Nervous system disorders | 1 of 60 | 0 of 60 | 1 of 60 | 1 of 60 |
| Tachycardia | Cardiac disorders | 0 of 60 | 1 of 60 | 0 of 60 | 1 of 60 |
| Restlessness | Psychiatric disorders | 0 of 60 | 1 of 60 | 0 of 60 | 1 of 60 |
| Abdominal pain | Gastrointestinal disorders | 0 of 60 | 0 of 60 | 1 of 60 | 0 of 60 |
| Diarrhoea | Gastrointestinal disorders | 0 of 60 | 0 of 60 | 1 of 60 | 0 of 60 |
| Dry mouth | Gastrointestinal disorders | 0 of 60 | 0 of 60 | 0 of 60 | 1 of 60 |
The adverse-event results list serious adverse events as 0 among 60 participants at risk for each treatment group: M2 0.5 mg, M2 1.5 mg, M3 0.5 mg, and M3 1.5 mg. This means no serious adverse events were recorded in the posted group summaries during the reported observation, not that the treatments are free of serious risks. The registry does not report enough detail to establish the duration or completeness of safety follow-up.
For other adverse events, the posted counts were 12 for M2 0.5 mg, 10 for M2 1.5 mg, 7 for M3 0.5 mg, and 13 for M3 1.5 mg, each with 60 at risk. These are counts, not rates adjusted for exposure time. In a crossover design, the same participant may contribute to more than one treatment group's safety summary, so the counts should not be added to estimate the number of people affected. The registry does not provide event-level descriptions or severity and relatedness details in these results.
Deaths are not reported in the registry record. The absence of a posted serious-event count in these summaries should be interpreted as a descriptive finding limited to the registry's reporting, not as proof that no events could occur.
13. What the Result Does, and Does Not, Mean
The results describe how PC20 differed across the treatment conditions in a single-dose pharmacodynamic study among participants with stable, mild to moderate asthma. The fitted mean PC20 values were higher for the 1.5 mg labelled treatment than for the 0.5 mg labelled treatment within both formulations. The corresponding mixed-model estimated mean ratios were 1.87 for M2 and 1.79 for M3, each with a 95% confidence interval excluding the no-difference ratio and a reported p-value of p < 0.001.
For the comparison between M3 and M2 at 0.5 mg, the estimated mean ratio was 0.92, with a 95% confidence interval from 0.75 to 1.13. At 1.5 mg, the estimated mean ratio was 0.88, with a 95% confidence interval from 0.72 to 1.08. These intervals include the no-difference ratio. The results therefore do not establish a formulation difference at either labelled dose, but they also do not establish that the formulations are equivalent or non-inferior. The registry does not state a clinical or statistical margin for those claims.
PC20 is a response to a methacholine challenge. It is not a direct measure of long-term symptom control, asthma exacerbations, quality of life, or other clinical outcomes. The study's single-dose design and short treatment periods also restrict conclusions to the conditions tested. The registry record does not report longer-term results or a threshold for a clinically important PC20 change.
The results do not show that either formulation should be selected in practice, nor do they provide medical advice. They describe the posted pharmacodynamic comparisons and their statistical precision. Unreported details—including the exact model specification, multiplicity handling, missing-data methods, and dose-label relationship—further limit what can be concluded from the registry record alone.
14. Why This Trial Matters Statistically
This trial is statistically informative because a crossover design compares several treatments within a study in which treatment responses may be correlated within participants. That structure can support direct treatment contrasts, but it also makes the analysis dependent on how within-person correlation, treatment periods, and possible carryover are handled. The registry identifies a mixed-model analysis, yet does not give enough detail to assess those choices. It is a useful reminder that a method label alone does not fully describe an analysis.
The endpoint also illustrates the distinction between a mechanistic or pharmacodynamic response and a patient-centered outcome. PC20 measures the methacholine concentration associated with a defined fall in FEV1. It can distinguish responses under the challenge conditions, while not answering questions about longer-term control or other clinical outcomes. Statistical precision around a laboratory measure does not by itself establish clinical importance.
The two dose comparisons have confidence intervals excluding the no-difference ratio, while the formulation comparisons have intervals that include it. This contrast underscores why a non-significant or inconclusive comparison should not be treated as proof of sameness. Equivalence and non-inferiority require a margin and an analysis plan; those are not reported in the registry record.
Finally, the record contains multiple comparisons and does not describe multiplicity handling. Readers need to distinguish each reported comparison from conclusions across a family of tests. The sample-size illustrations are planning exercises based on observed effects, not observed power or evidence that the original study was adequately designed. These issues are broadly relevant when interpreting small, single-dose crossover pharmacodynamic studies.
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 registry record does not report the full statistical model specification. In particular, it does not describe the model terms, covariance structure, period and sequence handling, or diagnostic checks. These details are important for assessing mixed-model estimates in a crossover study. The record also does not state whether carryover was assessed or how it was addressed.
Although the study is described as double-blind and double-dummy in its title and summary, the registry lists triple masking. The record does not clarify the masked roles or explain the relationship between these descriptions. It lists active M2 and M3 arms by 0.5 mg and 1.5 mg dose labels, while the per-inhalation descriptions state 0.5 mg terbutaline for M2 and 0.4 mg for M3. The relationship between these dose descriptions is not reported in the registry record.
Enrollment is 95, while each treatment's primary outcome summary lists n=60 in the efficacy analysis set. The record does not reconcile these figures or give participant flow by period. The set's inclusion criteria, missing-data handling, and any sensitivity analyses are also not reported. These gaps make it difficult to assess how exclusions or incomplete crossover measurements may have influenced the estimates.
The registry reports four primary-outcome comparisons but does not describe the multiplicity plan, identify confirmatory comparisons, or provide equivalence or non-inferiority margins. It does not report a clinical importance threshold for PC20. The sample-size justification and interim analyses are not reported in the registry record.
Finally, results are limited to a single-dose challenge outcome in stable, mild to moderate asthma. The registry does not report longer-term outcomes, detailed event-level safety results, or death counts. The safety summaries are descriptive and do not establish comparative safety over extended treatment.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: Comparing the Efficacy of Bricanyl M2 and Bricanyl M3 at 0.5 and 1.5 mg Dose Levels, to Allow for a Switch From Bricanyl Turbuhaler M2 to Bricanyl Turbuhaler M3 — NCT02322788.
- Registry record last updated 2017-01-13; status last verified 2016-11.
- Results first posted 2016-11-07.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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19. Record Summary
This completed randomized Phase III study compared Bricanyl Turbuhaler M2 and M3 in a single-dose, 4-way crossover design among participants with stable, mild to moderate asthma. Enrollment was 95. The primary endpoint was methacholine PC20, reported as least-squares means with 95% confidence intervals for the efficacy analysis set.
Mixed-model analyses found higher estimated PC20 for the 1.5 mg labelled dose than the 0.5 mg labelled dose within each formulation. The same-dose comparisons between formulations had confidence intervals that included the no-difference ratio. The registry does not report a multiplicity plan, equivalence or non-inferiority margins, or sufficient model details for a full independent assessment. The findings are specific to the short-term challenge response and should not be read as evidence about longer-term asthma outcomes.