Safety Study of Ragweed Allergy Immunotherapy Tablet in Subjects 50 Years of Age and Older (Study P06081): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety Study of Ragweed Allergy Immunotherapy Tablet in Subjects 50 Years of Age and Older (Study P06081) (NCT00978029), a randomized phase 2 study. The primary outcome is The Proportion of Participants Reporting Treatment-emergent Adverse Events (AEs).

2. Clinical Question

The study focused on safety and tolerability rather than a clinical efficacy outcome. A treatment-emergent adverse event was defined as a new adverse event occurring after randomization, or a screening event that increased in severity after randomization. The definition does not require the event to be judged related to study treatment: an adverse event could be temporarily associated with use of a medicinal product whether or not it was considered related.

The registry identifies the study as randomized, triple-masked and parallel-group. Its primary endpoint is the proportion of participants with at least one treatment-emergent adverse event, not the total number of events or the severity of every event. Separate secondary outcomes concern selected oral and throat symptoms and discontinuation due to adverse events. Those outcomes provide additional safety descriptions but do not replace the primary question.

3. Trial Design

The registry record identifies NCT00978029 as a randomized, triple-masked, parallel phase 2 study sponsored by ALK-Abelló A/S. It lists enrollment as 203 and describes a 28-day study of a ragweed sublingual tablet in adults 50 years of age and older with ragweed-induced rhinoconjunctivitis, with or without asthma. The record lists the study as completed, with a start in 2009-11 and primary completion in 2010-02.

Participants were assigned to matching placebo, SCH 39641 6 Amb a 1-U, or SCH 39641 12 Amb a 1-U. All listed regimens were sublingual and once daily. The primary endpoint was assessed up to Day 42, while the treatment period described for the endpoint was 28 days. These are different time references: the endpoint observation window extended beyond the stated treatment duration.

The primary analysis population is described as all subjects as treated, consisting of randomized participants who received at least one dose of study treatment. The record states that 7 participants were excluded from this analysis due to non-compliance with GCP. The posted arm counts for the primary endpoint are 65 for placebo, 66 for the 6 Amb a 1-U arm and 65 for the 12 Amb a 1-U arm. These are the counts associated with the reported endpoint results; the registry does not provide a separate account of the disposition of every randomized participant in this information.

Although the record identifies randomization and triple masking, further operational details are not reported in the registry record. The method used to generate or conceal the allocation sequence, the identities of the masked parties, and the procedures used to maintain masking are not reported in the registry record. Nor is a detailed account of the protocol’s planned statistical methods reported in the registry record. The design labels alone do not establish how those procedures were implemented.

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: Due to non-compliance with Good Clinical Practice (GCP) 7 randomized participants who completed treatment were excluded from all subsequent analysis.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All subjects as treated (ASAT) consisting of all randomized participants who received at least one dose of study treatment. Due to non-compliance with GCP 7 participants were excluded from this 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.

6. Primary Endpoint

The registry lists the primary outcome as The Proportion of Participants Reporting Treatment-emergent Adverse Events (AEs), measured over Up to Day 42.

The primary endpoint is the proportion of participants reporting treatment-emergent adverse events up to Day 42. The event definition includes new events after randomization and pre-existing events that increased in severity after randomization. It also makes clear that an event need not have been considered caused by study treatment to count. Thus, this measure describes the occurrence of events during the specified period; it is not by itself an attribution of causality.

A proportion is useful for comparing how commonly participants experienced at least one event across treatment groups. It gives each participant a binary status for the endpoint: event reported or not reported. It does not convey how many events an individual experienced, how long they lasted, or their severity. Nor does the overall endpoint identify which event types contributed to the proportion. The registry lists selected adverse-event outcomes separately, including oral pruritus, ear pruritus, throat irritation, mouth oedema and discontinuation due to adverse events.

The posted proportions are 0.446 for placebo, 0.515 for SCH 39641 6 Amb a 1-U and 0.615 for SCH 39641 12 Amb a 1-U. These are the reported arm-level values; no confidence limits accompany these proportions in the primary outcome entries. The endpoint is a safety summary over a period described as up to Day 42, following a 28-day treatment period. It should therefore be interpreted as an observed event proportion over that observation window, rather than as an estimate of a long-term event rate.

General statistical context: binary outcomes are easy to interpret as participant-level frequencies, but the summary can conceal differences in event type, timing and seriousness. Other safety information is needed to describe those dimensions.

7. Results Posted in the Registry

• SCH 39641 6 Amb a 1-U: 0.0% (0/66) versus 0.0% (0/65) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0); unadjusted two-proportion z-test p = n/a.
• SCH 39641 12 Amb a 1-U: 0.0% (0/65) versus 0.0% (0/65) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: a participant either reported a treatment-emergent adverse event during the endpoint window or did not. The arm-level proportion summarizes the frequency of this status in each treatment group. The posted values are 0.446 for placebo, 0.515 for SCH 39641 6 Amb a 1-U and 0.615 for SCH 39641 12 Amb a 1-U. The corresponding primary analysis counts are 65, 66 and 65, respectively.

What does a proportion compare?

General statistical context: a proportion expresses the number of participants meeting a defined outcome relative to the participants included in that group’s analysis. For a binary outcome, this focuses on whether each participant experienced the event at least once, rather than counting repeated events. The measure is therefore suited to the registry’s stated endpoint, but it cannot describe the burden of repeated events or their timing. The posted outcome value should be interpreted according to the registry’s event definition and analysis population.

The endpoint definition is broad: it counts new adverse events after randomization and screening events that worsened after randomization. It includes events whether or not considered related to the medicinal product. That definition helps distinguish an event’s timing from an investigator’s judgment about attribution. A treatment-emergent event is not automatically a treatment-caused event.

What is the role of the Fisher exact method?

The sponsor reports Fisher Exact analyses for each active dose compared with placebo. General statistical context: Fisher’s exact test evaluates evidence of association between treatment group and a binary outcome using the observed allocation of participants across outcome categories. It is often used for categorical comparisons, particularly when the data are expressed as counts. The test result is not a measure of effect size; the reported percent difference and confidence interval provide separate information about the estimated contrast and its uncertainty.

The sponsor’s posted comparison for the 6 Amb a 1-U arm is a percent difference of 6.9, with a 95% confidence interval from -10.17 to 23.97 and p = 0.486. For the 12 Amb a 1-U arm, the percent difference is 16.9, with a 95% confidence interval from 0.01 to 33.83 and p = 0.078. The registry calls the comparison parameter Percent Difference. It does not further define the sign convention for that parameter in the information available, so the values are best quoted as posted rather than assigned an unreported interpretation of direction.

How should a p-value be understood?

General statistical context: a p-value measures how incompatible the observed data are with a specified null model, assuming that model and the analysis assumptions hold. It is not the probability that the null hypothesis is true, and it does not measure the probability that a result is due to chance. A p-value also does not describe the size or clinical importance of an effect. For that, the effect estimate and its confidence interval matter.

The posted p-values are 0.486 and 0.078. They belong to the sponsor’s individual Fisher Exact comparisons. The registry does not report whether these tests were adjusted for multiple comparisons. Without that information, they should not be interpreted as multiplicity-controlled results.

What does randomization contribute?

General statistical context: random allocation is intended to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics at the time of assignment. It does not guarantee that every characteristic will be balanced in a particular trial, and the registry design label does not provide details of the allocation procedure. The record identifies the study as randomized, but the sequence generation and allocation concealment methods are not reported in the registry record.

The analysis is described as all subjects as treated, including randomized participants who received at least one dose, with 7 excluded for non-compliance with GCP. This is not identical in wording to an analysis of every randomized participant regardless of treatment received. The registry does not report the reasons for the GCP-related exclusions, their treatment assignments, or how excluded participants’ outcomes were handled. Those details matter when judging whether the analyzed population could differ from the randomized population.

Why can over-dispersion matter?

General statistical context: over-dispersion is relevant when a statistical model assumes a particular amount of variability but the observed data vary more than that model allows. It can make standard errors too small and confidence intervals too narrow if not addressed. It is especially a concern for count outcomes or clustered data under some models. The primary endpoint is a binary participant-level proportion, and the registry reports Fisher Exact comparisons; it does not report a dispersion parameter or a model requiring an over-dispersion adjustment. No over-dispersion assessment is reported in the registry record.

The registry’s methods information does not give a detailed statistical analysis plan, missing-data strategy, or adjustment approach beyond the named Fisher Exact comparisons. Consequently, the posted results can be described, but additional methodological decisions cannot be inferred from the record.

10. Confidence Intervals and Precision

The sponsor reports a 95% confidence interval from -10.17 to 23.97 for the percent difference comparing SCH 39641 6 Amb a 1-U with placebo. For SCH 39641 12 Amb a 1-U compared with placebo, the reported 95% confidence interval is from 0.01 to 33.83. These intervals convey uncertainty around the sponsor’s comparison estimates under the method used. They are not ranges containing 95% of individual participants’ outcomes, and they are not probabilities that the true effect lies within a particular interval.

The first interval includes zero, whereas the second has a lower endpoint of 0.01. The interval for the 12 Amb a 1-U comparison also extends to 33.83, illustrating that the estimate remains uncertain across a broad range of possible values on the reported scale. The registry identifies the comparison parameter as Percent Difference but does not provide further detail on its sign convention in the information available. Interpret the estimate and interval as reported rather than supplying an unreported direction.

The confidence intervals apply to the sponsor’s comparisons, not to each arm-level proportion. The primary outcome entries give the proportions and analysis counts but no confidence intervals for those individual proportions. This limits direct assessment of the precision of each arm estimate from the registry results alone.

General statistical context: a confidence interval gives an interval of estimates that are reasonably compatible with the observed data and the specified method, under its assumptions. Wider intervals indicate less precision than narrower intervals on the same scale. The interval does not capture every source of uncertainty, including possible bias from missing outcomes, exclusions, outcome assessment or analysis choices. The registry does not report enough detail to assess all such sources.

11. Analyses Reported by the Sponsor

The sponsor’s posted analyses compare each SCH 39641 dose with placebo using Fisher Exact methods. For the 6 Amb a 1-U comparison, the sponsor reports a percent difference of 6.9, a 95% confidence interval from -10.17 to 23.97 and p = 0.486. For the 12 Amb a 1-U comparison, the reported percent difference is 16.9, the 95% confidence interval is from 0.01 to 33.83 and p = 0.078.

The primary arm proportions are 0.446 for placebo, 0.515 for 6 Amb a 1-U and 0.615 for 12 Amb a 1-U. The separate simple comparison entries in the posted data list risk-difference estimates of 0.0, with confidence limits of 0.0 to 0.0 for both active comparisons. Those entries do not correspond to the nonzero arm proportions or to the sponsor’s nonzero percent-difference estimates. The registry does not report an explanation for this mismatch. The discrepancy indicator is false, but that does not resolve the apparent inconsistency among the posted comparison fields.

For interpretation of the stated sponsor analyses, the sponsor’s own reported estimates and intervals should be distinguished from the separate zero-valued comparison entries. No recalculation is needed to describe the sponsor results, and the registry does not provide further detail that would reconcile the comparison outputs.

12. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is one of several safety outcomes listed in the registry. The record lists five secondary outcomes: oral pruritus, ear pruritus, throat irritation, mouth oedema and discontinuation due to adverse events. It also reports two comparisons of active treatment with placebo for the primary endpoint. The registry does not report whether the sponsor adjusted p-values or confidence intervals for these multiple outcomes and comparisons.

General statistical context: when many hypotheses are tested, the chance of at least one apparently notable result can increase if each is assessed independently using the same criterion. Multiplicity procedures can address that issue, but the appropriate approach depends on which outcomes and comparisons were planned and their roles in the analysis. Without a reported analysis hierarchy or adjustment method, the posted p-values should be treated as individual reported tests, not as evidence that a family of tests was controlled at a particular error rate.

The registry record also does not report a missing-data method for the primary outcome. It does not state how participants with incomplete follow-up, missing event assessments or early discontinuation were handled for this endpoint. The primary analysis population is described as all subjects as treated who received at least one dose, with 7 excluded for non-compliance with GCP. The reasons for those exclusions and their outcome data are not reported in the registry record.

These omissions limit assessment of whether the analyzed participants represent the randomized population and whether incomplete follow-up could affect the reported proportions. General statistical context: missing outcomes can matter when the chance of missingness is related to treatment or to the outcome itself. A complete-case proportion may not describe all randomized participants if missingness is informative. No imputation or sensitivity analysis is reported in the registry record, so its effect on the results cannot be evaluated from the posted information.

The record does not report a detailed protocol-based statistical analysis plan, sample-size justification, or interim-analysis plan. These details should not be inferred from the endpoint results or from the design labels.

13. 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: cholecystitis acute (1.5%), post procedural bile leak (1.5%).

The serious adverse-event summary reports no serious events in the placebo group, no serious events in the SCH 39641 6 Amb a 1-U group, and one serious event in the SCH 39641 12 Amb a 1-U group. The corresponding numbers at risk are 65, 66 and 65. The registry lists acute cholecystitis and post procedural bile leak among the top serious-event terms, each with a reported value of 1.5%. It does not identify which treatment group each term belongs to in the information available.

The serious-event counts are distinct from the broader primary endpoint, which counts treatment-emergent adverse events whether or not they were considered related to the medicinal product. A serious event is not automatically treatment-related, and the registry summary does not provide causality assessments for these terms. The record does not report a death count; deaths are listed as null, so this should not be interpreted as confirmation that no deaths occurred.

General statistical context: rare safety events are difficult to compare precisely in studies of limited size. A small count can describe what was observed in the trial but may not characterize the frequency of uncommon events beyond it. These figures are descriptive and do not establish a causal relationship or provide a precise estimate of risk.

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

The results describe treatment-emergent adverse events reported during the endpoint period, up to Day 42, after a treatment period described as 28 days. The arm proportions are 0.446 for placebo, 0.515 for SCH 39641 6 Amb a 1-U and 0.615 for SCH 39641 12 Amb a 1-U. The sponsor’s comparisons report percent differences of 6.9 and 16.9, with confidence intervals from -10.17 to 23.97 and from 0.01 to 33.83, respectively.

These results do not establish that the study tablets caused the reported events. The endpoint definition includes events whether or not considered related to the medicinal product, so the total includes events with differing possible explanations. The registry does not provide a full event-by-event account or detailed attribution for the primary endpoint in the information available.

The findings also do not establish the absence of safety concerns. The study’s observation period was limited, and the serious-event summary includes one serious event in the 12 Amb a 1-U arm. The registry lists two serious-event terms with values of 1.5% but does not link them to a specific arm in the information available. It does not report a death count in the posted serious-event fields.

General statistical context: failure to demonstrate a clear difference is not proof that two treatments have identical event rates. Conversely, a numerical difference or a confidence interval that does not include zero is not, by itself, proof of a causal or clinically important effect. Interpretation depends on the analysis plan, the outcome definition, the validity of follow-up, the precision of estimates and the broader clinical context. The registry information does not report all of those elements.

The results are specific to the studied population, regimens and follow-up described in the record. They should not be generalized automatically to other ages, populations, doses, treatment durations or observation periods. They are a record of the reported trial outcomes, not medical advice or a stand-alone basis for treatment decisions.

15. Why This Trial Matters Statistically

This trial illustrates several statistical issues common in safety studies. First, the primary endpoint is a participant-level proportion, which offers an accessible summary of whether an adverse event occurred but compresses event type, severity, recurrence and timing into a single indicator. The separately listed oral and throat outcomes show why an overall safety measure may need event-specific context.

Second, the study has three arms and the sponsor reports two active-versus-placebo comparisons. Each comparison has its own estimate, confidence interval and p-value. When several comparisons and outcomes are considered, interpretation depends on whether the analysis plan specified a hierarchy or multiplicity adjustment. Those details are not reported in the registry record.

Third, the primary analysis population is described as all subjects as treated, with 7 participants excluded for GCP non-compliance. That makes the distinction between randomized participants and the analyzed population important. Without information about the exclusions and missing outcomes, readers cannot fully assess how the analysis population relates to the original randomized groups.

Fourth, rare serious events require cautious interpretation. The serious-event summary reports one event in one arm and none in the other two, but a small number of events provides limited precision for comparative conclusions. These counts are useful as descriptive safety information, not as definitive estimates of uncommon-event risks.

Finally, the posted comparison entries include zero-valued risk differences alongside nonzero arm proportions and nonzero sponsor estimates. The registry does not explain this mismatch. Recognizing inconsistent reporting is part of statistical interpretation: numerical outputs should be checked for coherence before being used to make comparisons. The sponsor’s reported analyses and the arm-level endpoint values can be described, while the unexplained zero entries remain a limitation of the posted record.

16. 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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

The registry information has important limitations for interpreting the safety findings. The primary endpoint is reported as an overall proportion, without confidence intervals for the individual arm proportions or detailed primary-endpoint event types in the information available. The summary therefore gives limited detail about the nature, severity, timing and recurrence of the events that contribute to the endpoint.

The analysis population excludes 7 participants for non-compliance with GCP. The registry does not report which arms those participants were assigned to, why each was excluded, or how their outcomes would affect an analysis including them. It also does not report a missing-data strategy or sensitivity analyses. The effect of exclusions and incomplete follow-up on the posted proportions cannot therefore be assessed from the record.

The sponsor reports two Fisher Exact comparisons, but a multiplicity adjustment, prespecified hypothesis hierarchy and detailed statistical analysis plan are not reported in the registry record. The record also does not report a sample-size justification or interim-analysis plan. No such design choices should be inferred from the posted results.

The separate comparison entries list zero-valued risk differences and zero-valued confidence limits, while arm proportions and sponsor comparisons are nonzero. The registry does not explain this inconsistency. The serious adverse-event terms are not linked to specific groups in the information available, and death counts are not reported as numeric values. These reporting gaps constrain interpretation of the safety summaries.

Finally, the study describes a 28-day treatment period and an endpoint timeframe up to Day 42. The results do not establish long-term safety or describe outcomes beyond the stated window. The registry record does not report further follow-up in the information summarized.

17. Related Tutorials

18. Related Statistical Calculators

19. Sources

• ClinicalTrials.gov: Safety Study of Ragweed Allergy Immunotherapy Tablet in Subjects 50 Years of Age and Older (Study P06081) — NCT00978029.
• Registry record last updated 2017-03-03; status last verified 2017-01.
• Results first posted 2014-05-23.
• 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.

20. Record Summary

NCT00978029 is a completed randomized, triple-masked, parallel phase 2 study sponsored by ALK-Abelló A/S. It enrolled 203 participants and evaluated once-daily sublingual SCH 39641 at 6 or 12 Amb a 1-U against matching placebo in adults 50 years of age and older with ragweed-induced rhinoconjunctivitis, with or without asthma. Treatment was described as lasting 28 days.

The primary endpoint was the proportion reporting treatment-emergent adverse events up to Day 42. Posted proportions were 0.446 for placebo, 0.515 for 6 Amb a 1-U and 0.615 for 12 Amb a 1-U. Sponsor comparisons with placebo used Fisher Exact methods and reported percent differences of 6.9 and 16.9, with respective 95% confidence intervals from -10.17 to 23.97 and from 0.01 to 33.83.

The primary analysis population was all subjects as treated; the record notes 7 exclusions for GCP non-compliance. Serious-event reporting lists no events in the placebo or 6 Amb a 1-U groups and one in the 12 Amb a 1-U group. Missing-data handling, multiplicity procedures and a detailed statistical plan are not reported in the registry record.