Study to Investigate Etokimab (ANB020) Activity in Adult Participants With Peanut Allergy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Investigate Etokimab (ANB020) Activity in Adult Participants With Peanut Allergy (NCT02920021), a randomized phase 2 study. The primary outcome is Number of Participants With Treatment-emergent Adverse Events (TEAEs).

2. Clinical Question

This is a proof-of-concept study in adults with peanut allergy, not a report of a large comparative trial. Its design places one dose of etokimab alongside a placebo infusion and records adverse events over a defined follow-up period. The posted safety summaries list no participants with serious adverse events in either arm. They also list other adverse events affecting participants in both arms. Those counts describe the observed safety data; by themselves, they do not establish whether the groups differ in risk or whether any event was caused by study treatment.

3. Trial Design

The registry identifies this as a Phase 2, randomized, quadruple-masked, parallel-group study. Its title describes a placebo-controlled proof-of-concept investigation of etokimab, also identified as ANB020, in adult participants with peanut allergy. Enrollment was 20. The study is recorded as completed, with a start date of 2017-01-26 and a primary completion date of 2018-03-30.

Participants assigned to etokimab received a single 300 milligrams dose by a 1-hour intravenous infusion on Day 1. Participants in the placebo group received a single placebo infusion by the same route and duration on Day 1. The registry lists randomization and quadruple masking, but the specific roles masked, allocation procedure, and planned allocation ratio are not reported in the registry record. The 15 and 5 participants listed in the safety groups are observed group counts, not a statement of the intended randomization ratio.

The primary outcome was the number of participants with treatment-emergent adverse events, with a timeframe from the first dose up to 45 days. The registry describes a safety analysis set consisting of participants who received any portion of either infusion. Secondary outcomes include change from baseline in oral food challenge symptom score at Day 14 and pharmacokinetic measures for etokimab, including concentration, time to maximum concentration, area under the concentration-time curve, half-life, clearance, and volume of distribution.

The record identifies two analyses and 12 outcome measures, but a complete statistical analysis plan, detailed analysis populations for each outcome, and the handling of missing observations are not reported in the registry record. The sponsor is AnaptysBio, Inc. No further design details should be inferred from the study title or outcome list.

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: On Day 1 eligible participants were randomized in a 3:1 ratio to receive one dose of either etokimab or placebo.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Safety Analysis Set included all participants who received any portion of etokimab or placebo infusion.

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: Randomization Analysis Set included all randomized participants.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment-emergent Adverse Events (TEAEs), measured over From first dose of study drug up to 45 days..

The primary endpoint is the number of participants with treatment-emergent adverse events, abbreviated TEAEs in the registry. It counts participants rather than the total number of distinct events. An adverse event is defined as an untoward medical occurrence in a participant who received a pharmaceutical product; the record notes that an event does not necessarily have a causal relationship to treatment. Clinically significant laboratory findings may also be considered adverse events.

An event qualifies as treatment-emergent when its onset is during or after the first dose, or when an event already present at baseline worsens in intensity or frequency after the first dose. The stated observation window runs from the first dose of study drug up to 45 days. The registry also says that events were assessed for severity and relationship to study drug. It defines serious events by outcomes such as death, life-threatening events, inpatient hospitalization or its prolongation, persistent or substantial incapacity, congenital anomaly or birth defect, and other important medical events.

Counting participants with at least one TEAE is a common way to summarize safety: it gives a participant-level indication of how many people experienced an event during the observation period. It does not convey the number of events per person, the duration of events, or their full clinical detail. The registry’s stated reason for collecting this endpoint is to evaluate safety and tolerability. The endpoint is not, on its own, a measure of peanut-allergy symptom improvement. The registry lists oral food challenge symptom score as a secondary outcome, but its numerical result is not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary participant-level outcome: each participant either met the registry definition of at least one treatment-emergent adverse event during the specified window or did not. The reported endpoint is a count of participants in each category, rather than a continuous measure such as a laboratory value or symptom score. This kind of outcome is often summarized by the number of participants with an event and the number assessed. The posted safety summary gives group counts, but it does not provide a single inferential comparison for the primary endpoint.

What the event count captures

Counting participants with at least one event makes the summary easy to interpret as a number of people affected. However, it treats a participant with one event the same as a participant with multiple events for this particular endpoint. It also does not describe how long events lasted, whether they recurred, or how their severity was distributed. The registry says severity and relationship to study drug were evaluated, but detailed results for those assessments are not reported in the registry record.

Definitions matter for reproducibility. In this study, an event was treatment-emergent if it began during or after the first dose, or if a baseline event worsened in intensity or frequency after dosing. The timeframe is from first dose up to 45 days. The event definition also allows clinically significant laboratory findings to count as adverse events. These rules specify what belongs in the endpoint, but the detailed event listings and adjudication procedures are not reported in the registry record.

Comparing groups

In general, a randomized comparison can estimate how frequently an outcome occurred in the assigned groups, subject to the analysis population and missing-data assumptions. For binary outcomes, analysts may report a difference in event proportions, a relative measure, or a model-based estimate. Each summary emphasizes a different aspect of the comparison. No new comparison can be inferred from the arm counts alone without making an analytical choice, and the registry record does not report a single primary-endpoint comparison.

A confidence interval is a general statistical tool for showing uncertainty around an estimate. It gives a range of values compatible with the observed data under the chosen method and assumptions. Wider intervals indicate less precision; narrower intervals indicate greater precision. A confidence interval does not guarantee that the true value lies in the interval, and it does not resolve limitations in the design or data. No confidence interval for a primary endpoint contrast is reported in the registry record.

Tests of statistical significance address whether observed data are inconsistent with a specified null model under assumptions. A p-value is not the probability that the null hypothesis is true, nor does it measure clinical importance. Because a reported primary-endpoint comparison and its test are not available in the registry record, no significance claim can be made from these safety counts.

Planning calculations and observed results

General sample-size planning asks how many participants might be needed to detect a specified effect under stated assumptions. The record’s planning description refers to a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of an observed effect. These are planning illustrations, not the trial’s own design justification and not observed power. The registry record does not report the trial’s sample-size justification. The primary outcome is not reduced to one comparison in the available record, so planning figures should not be treated as a direct analysis of the posted safety endpoint.

Observed power is not a useful substitute for an uncertainty interval around an estimated effect. After data are collected, the observed group counts and their uncertainty are the relevant evidence. A planning illustration can describe how a hypothetical design might behave under assumptions; it cannot change what this study observed, and it cannot establish that an unreported effect was detected.

Why over-dispersion can matter in general

Over-dispersion occurs when variability in count data is greater than a statistical model expects. It can make standard errors too small if a model assumes less variability than is present, leading to overconfident intervals or tests. This concept is relevant to some repeated-event or count analyses, especially when participants can experience multiple events. The primary endpoint counts participants with an event, rather than the total number of events, and the registry does not report a model for repeated events. Over-dispersion should therefore be understood as a general modeling issue, not a reported feature or adjustment in this study.

More detailed methods, including the planned inferential model, covariates, confidence-interval method, missing-data procedure, and analysis sets for each outcome, are not reported in the registry record. Those omissions limit assessment of how a formal comparison would have been conducted. The counts remain useful as descriptive observations, but they should not be extended into claims about unreported statistical tests or treatment effects.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and identifies two analyses. The primary outcome is a count of participants with treatment-emergent adverse events, while the secondary outcomes include an oral food challenge symptom score and several pharmacokinetic measures. When a study examines multiple outcomes, time points, or analyses, the chance of obtaining at least one apparently notable result can increase if each is tested separately. General approaches to multiplicity include prioritizing a primary endpoint, adjusting significance thresholds, or interpreting secondary analyses as exploratory. The statistical plan and any multiplicity strategy are not reported in the registry record.

The registry describes the safety analysis set as all participants who received any portion of etokimab or placebo infusion. The posted adverse-event groups list 15 participants at risk for etokimab and 5 for placebo. The exact analysis population for each secondary outcome, and whether all randomized participants were included in each analysis, are not reported in the registry record. Randomization does not itself specify how participants with incomplete outcome data are handled.

Missing-data procedures can affect estimates when outcome information is unavailable. General options include analyzing available observations, imputing missing values under stated assumptions, or using models that account for observed data patterns. The appropriate approach depends on why information is missing and the outcome being analyzed. The number of participants with missing primary or secondary outcome data, reasons for missingness, and any imputation or sensitivity analyses are not reported in the registry record.

Without a stated analysis plan, outcome-specific sample sizes, missing-data details, and multiplicity handling, the registry record does not permit a full audit of the inferential strategy. The posted counts can still be read descriptively, with care not to treat unreported analyses as if they had been conducted or to infer a prespecified testing hierarchy.

11. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The serious adverse event summary lists zero affected participants among 15 at risk in the etokimab group and zero among 5 at risk in the placebo group. The death count is also zero in both groups. These figures describe what the registry lists for the reported follow-up; they do not establish that no serious event could occur with either treatment or that the groups have identical risk.

The other-adverse-event summary lists 15 affected participants among 15 at risk for etokimab and 5 among 5 at risk for placebo. This is a count of participants, not a count of individual events. A participant may have experienced more than one event, and the posted counts do not indicate how many events each participant had. The available summary does not give event terms, severity distributions, onset patterns, or participant-level details for these other events.

The primary endpoint is specifically treatment-emergent adverse events, while the adverse-event groupings distinguish serious and other events. The group counts should be read in the context of the registry’s event definition and follow-up window, from first dose up to 45 days. The record says that severity and relationship to study drug were evaluated, but detailed results of those evaluations are not reported in the registry record. An adverse event is not necessarily caused by the study treatment.

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

The posted results support a limited factual account: the safety groups list no serious adverse events and no deaths, while other adverse events are listed for participants in both treatment groups. The numbers describe this study’s observed participants and its recorded follow-up. They do not show that a treatment caused or prevented an event, and they do not establish equivalence between etokimab and placebo.

The study was a randomized, quadruple-masked Phase 2 investigation with 20 participants enrolled. That design can support an exploratory comparison, but the number of participants and the absence of a reported primary-endpoint effect estimate constrain what can be inferred. In particular, zero serious events in the posted summary cannot rule out uncommon harms. It also cannot be interpreted as proof of no risk. A larger evidence base and full outcome reporting would be needed to characterize uncertainty more fully; such information is not reported in the registry record.

The title and secondary outcome list indicate that the study also examined etokimab activity, including oral food challenge symptom score change at Day 14, along with pharmacokinetic measures. Those outcomes’ numerical results are not reported in the registry record. Consequently, the safety counts cannot answer the symptom or pharmacokinetic questions, and the study’s stated purpose should not be mistaken for a posted efficacy result.

In general, a treatment effect is an estimate of a contrast between groups, interpreted with uncertainty and in light of the study design. The available adverse-event counts do not supply a single contrast, confidence interval, or inferential test for the primary outcome. Readers should therefore distinguish the observed counts from conclusions about comparative safety, clinical benefit, or risk in other populations. None of those broader conclusions follows from the posted summary alone.

13. Why This Trial Matters Statistically

This trial is statistically notable for the distinction between a stated primary endpoint and the limited comparative result available in the registry record. The endpoint is the number of participants with treatment-emergent adverse events, a participant-level safety measure. Yet the posted information does not reduce the primary outcome to one treatment comparison with an effect estimate and uncertainty interval. That difference matters: naming an outcome is not the same as reporting a complete analysis of it.

The safety summary also illustrates why raw counts require context. The etokimab and placebo groups have different numbers of participants at risk, and the record reports zero serious adverse events in both groups. Those observations are meaningful descriptions, but no comparative estimate is reported to quantify uncertainty or support a formal conclusion about group differences. Sparse event data can be especially uninformative about uncommon outcomes, even when the recorded count is zero.

The study’s masking and randomization are design features that can help limit bias, but transparency about the analysis remains important. The record does not report the full statistical plan, the primary outcome’s inferential method, missing-data handling, or multiplicity strategy. Those details are necessary for readers to understand how planned questions were linked to the analyses and how uncertainty was handled.

The trial also highlights the difference between safety, activity, and pharmacokinetics. The primary safety outcome and the secondary oral food challenge and concentration measures address different questions. Numerical results for the secondary outcomes are not reported in the registry record. A statistical reading keeps those domains separate and avoids inferring one from another. This is useful practice when interpreting proof-of-concept studies, where the record may describe a broad set of aims but offer only limited numerical findings.

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.

Interpretation is constrained by the limited outcome-level information in the registry record. The record gives group counts for serious and other adverse events, but it does not provide event terms, individual event counts, severity distributions, timing, or detailed attribution assessments. Although the primary outcome concerns treatment-emergent adverse events, a single comparative estimate and its uncertainty are not reported in the registry record.

The study enrolled 20 participants, and the posted safety groups list 15 participants at risk in the etokimab arm and 5 in the placebo arm. These group sizes limit the information available about infrequent events and make broad generalization inappropriate. The registry does not report the intended allocation ratio, reasons for the observed group counts, or participant flow through each analysis. No explanation should be inferred from the listed counts.

The primary outcome timeframe is stated as extending from first dose up to 45 days. Longer-term safety follow-up is not described in the available record. Although secondary outcomes include oral food challenge symptom score change at Day 14 and several pharmacokinetic measures, their numerical results are not reported in the registry record. The record also does not report the statistical analysis plan, the sample-size justification, interim analyses, missing-data procedures, or multiplicity handling.

These limitations do not erase the descriptive safety information, but they restrict conclusions about treatment effects and precision. The absence of a reported serious event is not evidence that the true risk is zero, and counts of other adverse events do not establish causation. The registry record supports only cautious statements about the listed participants and outcomes.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study to Investigate Etokimab (ANB020) Activity in Adult Participants With Peanut Allergy — NCT02920021.
• Registry record last updated 2023-07-27; status last verified 2023-07.
• Results first posted 2023-07-27.
• 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

NCT02920021 is a completed randomized, quadruple-masked, parallel-group Phase 2 study of etokimab in adults with peanut allergy. Enrollment was 20. Participants received a single Day 1 infusion of etokimab 300 milligrams or placebo, each over 1 hour. The primary outcome was the number of participants with treatment-emergent adverse events from first dose up to 45 days.

The posted safety groups list 15 participants at risk for etokimab and 5 for placebo. Serious adverse events and deaths are listed as zero in both groups. Other adverse events are listed for 15 of 15 participants in the etokimab group and 5 of 5 participants in the placebo group. These are descriptive counts, not a reported comparative effect estimate.

The registry lists oral food challenge symptom score change and pharmacokinetic measures as secondary outcomes, but their numerical results are not reported in the registry record. The primary outcome’s comparative statistical analysis, missing-data methods, and multiplicity strategy are also not reported in the registry record.