Biomarkers of Cockroach Sublingual Immunotherapy 2: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Biomarkers of Cockroach Sublingual Immunotherapy 2 (NCT01380327), a randomized phase 1, phase 2 study. The primary outcome is Change in German Cockroach-Specific Serum IgE Over Time.

2. Clinical Question

The study, NCT01380327, is titled “Biomarkers of Cockroach Sublingual Immunotherapy 2.” Its official title describes a biomarker-based pilot study of cockroach sublingual immunotherapy in cockroach-sensitive children with asthma and/or perennial allergic rhinitis. The registry identifies asthma and perennial allergic rhinitis as the conditions studied. Its brief summary frames the work as a follow-up to the ICAC-12 Phase I/II trial and says it was designed to study immune-response biomarkers and safety in a pediatric population.

The clinical question is therefore focused on biological response and safety rather than on a patient-centered clinical benefit endpoint. The primary outcome measures serum IgE specific to German cockroach over time. Secondary outcomes include German cockroach-specific serum IgG and IgG4 changes, IgE fragment antibody binding activity, and the percentage of participants with adverse events. These measures address different aspects of immune response and tolerability; they should not be treated as interchangeable evidence.

The registry reports comparisons of high-dose immunotherapy with placebo and low-dose immunotherapy with placebo. It does not report a direct comparison between the two active regimens. Nor does the registry record establish whether a biomarker change corresponds to a change in symptoms, asthma control, allergic rhinitis, or another clinical outcome. Those questions are outside what the posted primary results can answer.

3. Trial Design

The registry classifies NCT01380327 as a Phase 1 and Phase 2 randomized trial with a parallel design and quadruple masking. The recorded enrollment is 99. The status is completed. The listed start is 2011-05 and the primary completion is 2012-06. The sponsor is the National Institute of Allergy and Infectious Diseases (NIAID).

Participants were assigned among three intervention groups: cockroach sublingual immunotherapy at a high dose, the same therapy at a low dose, or placebo. The active intervention was glycerinated German cockroach (Blatella germanica) allergen extract, administered sublingually. The low-dose regimen is described as a maximally tolerated dose of 420 microliters daily; the high-dose regimen as a maximally tolerated dose of 840 microliters taken twice daily. Placebo was also administered sublingually, with the maximum dose tied to low-dose or high-dose randomization.

Randomization and masking are design features intended to support fair comparison and reduce bias. The registry does not describe the randomization sequence, allocation concealment, the identities of the masked parties, or how masking was maintained. Further protocol details are not reported in the registry record. The registry also does not report the intended allocation ratio or planned number of participants in each arm.

The primary outcome is described for an intent-to-treat population with complete data. The reported arm counts for that outcome are 30 for high dose, 30 for low dose, and 28 for placebo. These are the counts attached to the primary outcome results, not a replacement for the overall enrollment figure. How participants with incomplete outcome data were handled, and why the primary-outcome counts differ from overall enrollment, are not reported in the registry record.

The registry lists five outcome measures and eight analyses. Four secondary outcomes are named, in addition to the primary outcome. Details of the schedule of secondary outcome assessments, the full analysis plan, and any protocol amendments are not reported in the registry record. The study’s pilot designation and biomarker emphasis give useful context, but they do not establish a particular sample-size rationale or a confirmatory testing plan.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent-to-treat population with complete data.

5. Baseline Characteristics

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

6. Primary Endpoint

The registry lists the primary outcome as Change in German Cockroach-Specific Serum IgE Over Time, measured over Baseline through 3 months of treatment.

The primary endpoint is “Change in German Cockroach-Specific Serum IgE Over Time.” It is measured as a ratio of geometric means for baseline versus post-baseline German cockroach-specific serum IgE, over baseline through 3 months of treatment. The registry identifies the result as an indicator of immune modulation over time and explicitly notes that its clinical significance is unclear.

A geometric mean is a way to summarize measurements that are interpreted on a multiplicative scale. It can be useful when values are skewed or when relative changes are more meaningful than absolute differences. A ratio expresses one geometric mean in relation to another, rather than describing a change in the original measurement units. The endpoint’s stated unit is “Ratio.” The registry does not give the assay details, the exact post-baseline time points used in the summary, or the direction convention for the baseline-versus-post-baseline ratio. Those details are not reported in the registry record.

The endpoint is relevant to a biomarker-focused study because it tracks an immune measure over time during allergen immunotherapy. It does not directly quantify symptoms or day-to-day disease control. A biomarker can change without establishing that participants feel better or have fewer clinical events; conversely, a clinical effect cannot be inferred from this endpoint alone. The registry’s caution that clinical significance is unclear is important when interpreting the estimates.

The primary outcome population is described as intent-to-treat participants with complete data. This wording combines an intent-to-treat label with a complete-data condition. The registry does not explain the analysis population definition, how missing measurements were addressed, or whether all randomized participants contributed to each time point. These details affect how broadly the result can be interpreted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a geometric-mean ratio describe?

Geometric means summarize measurements using a multiplicative scale. They are often used when measurements are positive and relative changes are of interest, or when values have a skewed distribution. A ratio compares one geometric mean with another and is dimensionless, consistent with the registry’s stated unit of “Ratio.” It does not directly give a difference in the original measurement units.

The primary outcome compares baseline with post-baseline German cockroach-specific serum IgE over baseline through 3 months of treatment. The record describes the result as a ratio of geometric means, but does not specify the detailed calculation convention or the exact post-baseline measurements included. Thus, the reported ratios should be read using the registry’s stated definition rather than translated into an absolute IgE change. The direction convention is not reported in the registry record.

How should confidence intervals be read?

A confidence interval communicates the precision of an estimate under the analysis assumptions. A narrower interval indicates less statistical uncertainty than a wider interval on the same scale. It does not show the spread of individual participant responses and does not guarantee that the true effect is inside the interval. The registry reports 95% confidence intervals for the arm summaries and for both mixed-model comparisons.

For the high-dose comparison, the reported estimate is 1.7, with a 95% confidence interval from 1.2 to 2.3. For low dose, the estimate is 2.3, with a 95% confidence interval from 1.7 to 3.1. The intervals express uncertainty around the respective reported comparisons. They should not be used to infer a direct contrast between active doses, because that comparison is not reported.

What does the mixed-model analysis contribute?

The registry names “Mixed Models Analysis” as the method for the two comparisons. In general, mixed models can analyze repeated measurements while accounting for the fact that observations from the same participant are related. They can also accommodate some forms of incomplete repeated-measure data, depending on the model and assumptions. These are general properties, not a description of the exact model used in this trial.

The registry does not specify the model terms, covariance structure, link or distribution, adjustment variables, handling of missing observations, or estimation procedure. It also does not explain why the comparison parameter is labeled “Risk Ratio (RR)” for a continuous biomarker summary. Those details are not reported in the registry record, so it is not possible to assess the model specification or reproduce the analysis from the posted summary alone.

How do p-values relate to estimates?

A p-value describes how compatible the observed data are with a specified null hypothesis under the model and its assumptions. It does not measure the size or importance of an effect, and it is not the probability that the null hypothesis is true. The registry reports p = 0.001 for high dose versus placebo and p < 0.001 for low dose versus placebo. Those values accompany the estimates and confidence intervals; they should not replace attention to the magnitude, uncertainty, endpoint meaning, and design.

Because the registry does not describe any multiplicity adjustment, the reported p-values should be understood as posted, without assuming control of error across all outcomes or analyses. Whether the primary outcome was prespecified in a detailed analysis plan, or whether any interim analyses occurred, is not reported in the registry record.

What can be said about planning illustrations?

Any sample-size illustrations based on an observed effect are planning examples, not evidence about the probability that this completed trial detected an effect. The registry’s stated assumptions describe two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of the observed effect. Time-to-event illustrations are defined in terms of total events; other illustrations are in participants per arm. These assumptions do not establish the trial’s original design rationale or its actual allocation plan.

The sample-size justification, original target by arm, and any allowance for incomplete data are not reported in the registry record. A planning illustration derived from the observed results should not be described as observed power. It is conditional on its assumptions and on the observed estimate, which is itself uncertain.

Why does the analysis population matter?

The primary outcome population is called intent-to-treat with complete data. In general, intent-to-treat analysis refers to analyzing participants according to randomized assignment, while a complete-data restriction indicates that an outcome measurement is required for inclusion in the analysis. The registry does not explain how these terms were operationalized together, whether participants were included if some time points were missing, or how the model used incomplete observations.

Missing-data methods can affect estimates when the probability of missingness is related to participant characteristics or outcomes. No specific missing-data assumption or sensitivity analysis is described in the registry record. Consequently, the posted estimates are interpretable as the results for the registry’s stated analysis population, while the extent to which they generalize to all randomized participants is uncertain.

10. Analyses Reported by the Sponsor

The registry’s posted comparisons are identified as mixed models analyses. For high-dose immunotherapy versus placebo, the reported estimate is 1.7, with a 95% confidence interval from 1.2 to 2.3 and p = 0.001. For low-dose immunotherapy versus placebo, the estimate is 2.3, with a 95% confidence interval from 1.7 to 3.1 and p < 0.001. These are the sponsor analyses represented in the posted results.

No discrepancy is flagged between the reported analyses and any recalculated result. The registry record does not present a separate unadjusted re-calculation for these comparisons in the registry record for interpretation. As a result, there is no independent numerical re-calculation to place alongside the mixed-model estimates. The sponsor’s own analysis is the relevant reported comparison.

The analysis labels and model details deserve a measured reading. The primary outcome is a geometric-mean ratio over time, while the comparison parameter is named “Risk Ratio (RR).” The model specification and the exact derivation of this comparison are not reported in the registry record. Without those details, the posted estimates can be described, but their calculation cannot be independently reconstructed from the summary alone.

The reported confidence intervals and p-values concern the biomarker outcome, not clinical outcomes. They do not establish a clinical benefit, and the record explicitly says the clinical significance of immune modulation is unclear. No direct active-dose comparison is reported.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists five outcome measures and eight analyses. It names the primary serum IgE outcome and four secondary outcomes: German cockroach-specific serum IgG change, German cockroach-specific serum IgG4 change, IgE fragment antibody binding activity change, and the percentage of participants with adverse events. The posted primary comparisons are high dose versus placebo and low dose versus placebo.

When many outcomes, time points, or treatment contrasts are examined, the chance of at least one apparently notable result can increase. Statistical approaches can address this issue, but the registry does not report whether a multiplicity procedure was used, which outcomes or comparisons were included in any such procedure, or whether the primary endpoint was tested within a prespecified hierarchy. The posted p-values should therefore not be assumed to have been adjusted for the number of analyses.

The primary outcome population is described as intent-to-treat participants with complete data. The primary outcome counts are 30 for high dose, 30 for low dose, and 28 for placebo, while total enrollment is 99. The record does not explain which participants were excluded from these outcome counts, whether the counts reflect complete measurements at every time point, or how missing data were handled. The exact analysis-population rules and any missing-data sensitivity analyses are not reported in the registry record.

In general, missingness can affect an estimate if availability of a measurement is related to the outcome or to participant characteristics. A mixed model may use incomplete repeated observations under particular assumptions, but the registry does not state the assumptions or whether all available measurements were included. It is therefore not possible to judge from the posted summary whether missingness could have shifted the estimates.

Other design and analysis details are also absent: the statistical analysis plan, protocol-specific endpoint hierarchy, planned sample-size justification, interim analyses, and any amendments are not reported in the registry record. Their absence does not show that these procedures were or were not used. It limits what can be concluded about prespecification, multiplicity control, and the robustness of the reported findings.

12. 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: renal disorder (3.1%), asthma (3.1%).

The registry reports serious adverse event counts with 34 participants at risk in the high-dose group, 33 in the low-dose group, and 32 in the placebo group. The corresponding numbers reported as affected by serious adverse events are 0, 0, and 2. These counts describe the safety results as posted; they do not establish that every event was caused by the assigned intervention.

The serious-event terms listed are “Renal disorder” and “Asthma,” each reported as 3.1%. The registry summary does not identify the treatment group associated with each term, provide event timing, or describe severity, recurrence, or attribution. The percentages should not be assigned to an arm based on the group counts. The detailed event-level context is not reported in the registry record.

For other adverse events, the affected counts are 20 for high dose, 25 for low dose, and 21 for placebo, with 34, 33, and 32 participants at risk, respectively. These are counts, not a description of event type or severity. No deaths are represented by a numeric value in the posted safety details; the death counts are not reported in the registry record. They should not be interpreted as zero.

Safety counts in a pilot study are descriptive. Differences in counts do not by themselves establish a causal effect, and the record’s summary does not provide enough detail to evaluate event onset, exposure time, or comparative risk. The counts should be read alongside the limited population sizes and the incomplete detail in the registry’s adverse-event reporting.

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

The results support a narrow statistical statement: the registry reports mixed-model comparisons that distinguish each active regimen from placebo on the primary German cockroach-specific serum IgE outcome over the stated treatment period. The reported estimate is 1.7 for high dose versus placebo and 2.3 for low dose versus placebo, with the confidence intervals and p-values. This is evidence about a biomarker in the analyzed population, not a direct measure of clinical response.

The primary outcome description says the measure is an indicator of immune modulation, while also warning that its clinical significance is unclear. Accordingly, the posted estimates do not establish that asthma or perennial allergic rhinitis symptoms changed, that disease control improved, or that participants experienced a patient-important benefit. Those outcomes are not the primary endpoint reported in these results.

The results also do not demonstrate that low dose differs from high dose. Separate comparisons of each regimen with placebo cannot substitute for a direct comparison between the active regimens. Although the reported point estimates differ, the registry does not provide a statistical test or confidence interval for that active-dose contrast.

Nor do the findings establish the long-term response to treatment. The primary outcome timeframe runs from baseline through 3 months of treatment. Longer-term follow-up results are not described in the posted primary outcome details. The registry’s brief summary refers to study of biomarkers and safety in a pediatric population, but the record does not provide a basis for extrapolating beyond the participants and measures described.

The study is classified as a pilot and its overall enrollment is 99. The primary outcome counts are 30, 30, and 28. The registry does not report a sample-size justification, a confirmatory testing framework, or the handling of missing primary-outcome data. These limitations constrain the strength and scope of conclusions. Statistical evidence for a difference on this endpoint should not be recast as proof of clinical importance, comparative dose superiority, or broad applicability.

14. Why This Trial Matters Statistically

This study illustrates why statistical interpretation depends on the endpoint’s meaning as well as its p-value. The primary result concerns a biomarker measured over time, and the registry explicitly states that its clinical significance is unclear. Statistical evidence that an immune measure differs between groups is not, on its own, evidence of a clinically meaningful change in asthma or perennial allergic rhinitis.

It also illustrates the distinction between arm summaries and treatment comparisons. The registry gives geometric-mean ratio summaries for each arm and separate mixed-model contrasts against placebo. Those estimates answer related but different questions. The reported active-versus-placebo comparisons do not provide a direct test between the two active regimens, even when their point estimates are different.

Interpretation also depends on the analysis population. The record describes an intent-to-treat population with complete data, gives primary-outcome counts by arm, and reports overall enrollment. The relationship among these figures and the handling of incomplete observations are not explained. That gap makes it important to distinguish the posted analysis population from all enrolled participants.

Finally, the trial shows why safety summaries require restraint. Serious adverse event counts and event terms are posted, but the detailed group attribution and event context are absent from the summary. Small descriptive counts can inform a safety discussion without resolving causation or comparative risk. Taken together, the registry results are useful as a record of biomarker and safety analyses, while their limits define what they can support.

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 results are limited by the scope of the primary endpoint. It measures German cockroach-specific serum IgE as a ratio of geometric means over baseline through 3 months of treatment. The registry notes that the clinical significance of the measure is unclear. No direct clinical outcome result is included in the primary details, so the biomarker findings cannot be translated into a claim about symptoms or disease control.

The registry identifies a mixed models analysis but does not report the detailed model specification. The parameterization, repeated-measure structure, covariate adjustment, covariance assumptions, and handling of missing observations are not reported in the registry record. This prevents independent reconstruction of the estimates from the posted summary and limits assessment of model assumptions.

The analysis population is described as intent-to-treat participants with complete data. The primary-outcome counts are 30 for high dose, 30 for low dose, and 28 for placebo, compared with overall enrollment of 99. The registry does not explain the difference or give a detailed account of missing data and participant flow. The extent to which the analyzed participants represent all enrolled participants is therefore uncertain.

The registry does not report the sample-size justification, the planned allocation ratio, an analysis plan, multiplicity adjustment, or interim analyses. It also does not provide a direct high-dose-versus-low-dose comparison. Thus, the reported p-values cannot be assumed to account for the full set of outcomes and analyses, and the separate active-versus-placebo findings do not establish a difference between the active regimens.

Safety details are limited in the posted summary. Serious-event counts and two event terms are listed, but event attribution by arm, timing, and clinical context are not reported. Death counts are not reported in the registry record. These omissions constrain interpretation of the safety profile and prevent a fuller comparison of event patterns across groups.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Biomarkers of Cockroach Sublingual Immunotherapy 2 — NCT01380327.
• Registry record last updated 2014-06-11; status last verified 2014-06.
• Results first posted 2014-05-30.
• 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.

19. Record Summary

NCT01380327, “Biomarkers of Cockroach Sublingual Immunotherapy 2,” is a completed randomized, quadruple-masked, parallel Phase 1 and Phase 2 pilot study sponsored by the National Institute of Allergy and Infectious Diseases (NIAID). Its recorded enrollment is 99. The study population was cockroach-sensitive children with asthma and/or perennial allergic rhinitis.

Participants received high-dose or low-dose German cockroach sublingual immunotherapy, or placebo. The primary outcome was change in German cockroach-specific serum IgE from baseline through 3 months of treatment. The registry reports mixed-model comparisons against placebo, with estimates of 1.7 for high dose and 2.3 for low dose. The outcome is a biomarker, and its clinical significance is stated to be unclear.

Secondary outcomes covered German cockroach-specific IgG and IgG4, IgE fragment antibody binding activity, and adverse events. Serious adverse event counts were 0 in high dose, 0 in low dose, and 2 in placebo. The registry does not provide the detailed analysis, missing-data, multiplicity, or event-level information needed for broader conclusions.