LMN-101 in a Campylobacter Human Challenge Model: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for LMN-101 in a Campylobacter Human Challenge Model (NCT04182490), a randomized phase 2 study. The primary outcome is Number of Participants With Solicited or Unsolicited Adverse Events.

2. Clinical Question

The primary outcome is a safety measure: the number of participants with solicited or unsolicited adverse events. Its stated timeframe is Day 1 to Day 14. This question concerns recorded events during a defined regimen and challenge protocol, rather than a measure of whether the study drug prevents infection or improves a clinical outcome.

The challenge model is central to interpreting the question. Participants received C. jejuni inoculum after beginning their assigned regimen. The study description says antibiotics were started when early treatment criteria were met or 144 hours after challenge, whichever came earlier. The study therefore evaluates adverse-event reporting within a controlled research setting that included deliberate challenge and subsequent antibiotic treatment.

The posted outcome information includes counts for participants with serious and other adverse events. The record does not report an inferential comparison for the primary outcome, and its outcome note says the primary outcome has several categories or time points and was not reduced to one comparison. The registry record does not report an efficacy outcome result in this record.

3. Trial Design

This was a Phase 2, randomized, quadruple-masked, parallel-group, placebo-controlled study in healthy volunteers challenged with Campylobacter jejuni. The registry record lists enrollment of 42. It reports a 3000-mg cohort and a placebo cohort, with 21 participants at risk in each group. The sponsor was Lumen Bioscience, Inc.; the study status is completed.

Participants began their assigned LMN-101 or placebo regimen after documentation of informed consent. The brief study description says the regimen was taken three times daily and that the challenge inoculum was given after two days. The arm descriptions specify six 500-mg capsules orally three times daily for 14 days in both groups. The study therefore compares assignment to LMN-101 with assignment to placebo under a shared challenge and dosing schedule.

The protocol description includes antibiotic treatment after early treatment criteria were met or 144 hours following challenge, whichever came earlier. Participants could leave the research facility after antibiotics when symptoms had resolved or were resolving, the specified stool-culture criteria were met, and fever-related discharge conditions were satisfied. Participants were to use a diary card or memory aid and thermometer for at-home monitoring of solicited adverse events through Day 24. The description also says they would be contacted by telephone 6 months after challenge.

The registry record gives a study start date of 2022-02-21 and a primary completion date of 2022-10-04. It does not report further details of the randomization procedure, allocation concealment, or the identities of the masked parties. Those details are not reported in the registry record.

4. Participant Flow and Accounting

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

Overall Study

Reasons for not completing this period:

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: 42 healthy volunteers

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Solicited or Unsolicited Adverse Events, measured over Day 1 to Day 14.

The primary endpoint is the number of participants with solicited or unsolicited adverse events. The stated timeframe is Day 1 to Day 14, and the description refers to the protocol-specified collection duration for each type of adverse event. This is a participant-count endpoint: it concerns whether participants were recorded as having an event, rather than how many event episodes each participant experienced.

Safety endpoints are used to describe harms observed during a study regimen and to compare the pattern of recorded events between assigned groups. Solicited events are events specifically sought according to the study’s collection procedures; unsolicited events are those reported without being specifically prompted in the same way. The registry record does not give a breakdown of the primary endpoint by solicited versus unsolicited events, nor does it describe the specific event categories in the primary outcome text.

Counting participants can be useful because it indicates how many people in each group were affected, but it does not convey event duration, severity, recurrence, or timing unless those features are reported separately. A participant-count endpoint also does not by itself show that an event was caused by the assigned regimen. In this study, the challenge procedure and other protocol care are part of the context for interpreting reported events.

The posted results list counts for participants with serious adverse events and other adverse events. The registry record does not present a single inferential comparison for the broader primary endpoint, so these counts should be read descriptively rather than as a complete statistical test of the primary question.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a randomized, parallel-group comparison. Random assignment is intended to make treatment groups comparable on average with respect to factors known and unknown at baseline. Masking can reduce the influence of expectations on participant reporting, clinical assessment, and other study processes. The record identifies the study as quadruple-masked, but it does not state which specific groups of people were masked or provide details of the masking procedures. Those details are not reported in the registry record.

What does a participant count measure?

For a binary safety outcome, each participant is classified according to whether the specified event outcome occurred during the observation period. The reported count is the number classified as having an event; the at-risk count indicates the group denominator listed for that outcome. In this study, the posted serious-event figures are 0 among 21 in each group, while the other-event figures are 20 among 21 in the 3000-mg cohort and 18 among 21 in the placebo cohort. These counts describe people, not the total number of event episodes.

A binary summary is straightforward to read, but it compresses information. It does not show whether a participant experienced a single event or several, whether events were brief or prolonged, or whether event timing differed across participants. Those features require further summaries or event-level data. The registry record does not report those details for the posted counts.

Why do uncertainty intervals matter?

A confidence interval is a statistical range that describes the uncertainty around an estimated quantity under a specified model and method. For a comparison between groups, an interval can show which effect sizes remain compatible with the observed data and the analysis assumptions. It is generally more informative than a significance label alone because it communicates precision as well as direction and magnitude.

The registry record does not report a confidence interval or an inferential estimate for the primary outcome comparison. No such interval can be interpreted from the posted counts alone without selecting an analysis method and calculating a new result. The record’s outcome note says the primary outcome has several categories or time points and was not reduced to one comparison, and the record lists 0 analyses. The counts should therefore be treated as descriptive registry results, not as a completed inferential analysis.

What does the design contribute?

Randomized allocation and a placebo comparator create a basis for comparing the assigned groups within this study. Parallel-group design means participants were assigned to one group rather than crossing between the regimens. The shared challenge and stated dosing schedule define the setting for the contrast. The registry record does not report the randomization sequence generation, concealment method, or details of any stratification, so those design features cannot be assessed from this record.

Masking is relevant to safety reporting because awareness of assignment can affect expectations and reporting. However, masking does not eliminate all possible reporting or measurement differences, and the registry record does not give enough detail to assess how masking was maintained. The study’s diary and thermometer procedures, along with facility visits and follow-up contacts, are part of the stated monitoring plan; the record does not provide completeness or adherence results for those procedures.

How should planning calculations be read?

The study’s sample-size assumptions are described as a planning illustration computed from an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The stated effect to detect is a fraction of the observed effect. The record explicitly distinguishes such planning illustrations from the trial’s own design. They should not be interpreted as observed power, as evidence that a comparison was adequately powered, or as a substitute for an uncertainty interval around the observed result. The registry record does not report a sample-size justification or the trial’s own power calculation.

General statistical planning calculations depend on their assumptions. If the observed effect is used to define a future effect to detect, the resulting illustration is conditional on that effect and the selected model. It does not establish what effect the study was designed to detect. The record does not report the values of any planning rows in the information available for this interpretation, so no participant requirement or planning result can be stated.

Why can over-dispersion matter?

General explanation: over-dispersion occurs when observed variability is greater than a statistical model expects. It can make model-based standard errors too small if the extra variability is ignored, leading to intervals that are too narrow and tests that are too optimistic. This issue often arises with counts of events when event variation is larger than a simple model allows. The endpoint in this record is described as a participant count with an event, not a count of repeated event episodes, and the registry record does not report a model for over-dispersion. No over-dispersion adjustment is reported.

What analysis choices remain unknown?

The registry record does not report a statistical analysis plan, a specified effect measure for the primary comparison, a confidence-interval method, covariate adjustment, or a missing-data method. It also does not identify a defined analysis population. These choices can affect how safety data are summarized and how uncertainty is quantified. In their absence, the posted counts support a limited descriptive reading, but not a reconstruction of the sponsor’s intended inferential analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome measure, but its note says the primary outcome has several categories or time points and was not reduced to one comparison. This matters because testing or interpreting many event categories or time points can create multiplicity: the more comparisons considered, the greater the chance that an apparently notable result arises by chance. Methods such as prespecifying a primary contrast or adjusting for multiple comparisons can address this issue, but the registry record does not report a multiplicity strategy. It also lists 0 analyses, so no multiplicity-adjusted or unadjusted analysis result is available in the record.

The record gives a primary timeframe of Day 1 to Day 14 and describes protocol-specified collection durations for each type of adverse event. It does not provide a detailed schedule of all categories or time points covered by the outcome note. The adverse-event counts therefore cannot be assumed to represent a single, fully specified comparison across every category and collection period.

Missing-data handling is not reported in the registry record. The posted at-risk counts are 21 in each group, but the record does not state whether all assigned participants had complete primary-outcome information, how incomplete diaries or assessments were handled, or whether any participants were excluded from an analysis. The counts alone do not establish that there was no missing information.

Analysis populations are also not reported in the registry record. It does not specify whether the primary analysis was intended to include all randomized participants, participants who received the assigned regimen, or another defined group. These omissions limit assessment of potential bias and make it impossible to verify how participants were included in a formal comparison.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry record reports serious adverse events separately from other adverse events. In the 3000-mg cohort, the serious-event count is 0 among 21 participants at risk; in the placebo cohort, it is also 0 among 21. The record reports 0 deaths in each group. These figures mean that no participants were recorded in the corresponding serious-event or death categories in the posted results.

A zero count is not proof that the risk is absent. It describes what was observed and recorded in this study, and it does not rule out events that could occur in a larger or different population. The registry record does not provide an uncertainty interval for these counts or identify any serious adverse event terms; its list of top serious-event terms is empty.

The other-adverse-event counts are 20 in the 3000-mg cohort and 18 in the placebo cohort, with 21 participants at risk in each. These are counts of participants affected, not totals of event episodes. The record does not say which specific events are included, whether they were solicited or unsolicited, or how severe or prolonged they were. The counts should be read as descriptive safety information within the study’s challenge and treatment setting, not as a causal attribution to LMN-101.

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

The posted results describe adverse-event counts among participants assigned to LMN-101 or placebo in a randomized Campylobacter jejuni challenge study. They report no serious adverse events and no deaths in either group. They also report participants with other adverse events in both groups. These observations are limited to the reported categories and study context.

The results do not establish that LMN-101 caused or prevented any particular adverse event. Assignment was randomized, but the registry record does not report event-level information, a formal comparative analysis, or an analysis population. The counts do not show whether particular events occurred more than once, differed in severity, or were temporally related to dosing or challenge. Causal interpretation requires more detail than the aggregate participant counts available in the record.

The counts also do not answer whether LMN-101 changed the course of Campylobacter infection or any efficacy outcome. The primary outcome is an adverse-event measure, and the registry record does not report an efficacy result in the information described. Safety and efficacy are different questions and require their own endpoints and analyses.

General explanation: a randomized comparison can estimate differences between assigned groups when the outcome is measured consistently and the analysis is appropriate. Precision depends on the amount of information and the observed variation; a count by itself does not express that precision. Since the registry record reports no confidence interval or inferential comparison, the observed counts should not be treated as proof of equivalence, proof of a difference, or a definitive estimate of comparative risk.

Finally, the study population and conditions matter. These were healthy volunteers in a human challenge model with protocol-directed antibiotic treatment and follow-up. The registry record does not establish whether the findings apply to other populations, routine exposure, or settings with different care. The appropriate reading is descriptive: these are the counts reported for this completed study, with important detail and analysis limitations.

13. Why This Trial Matters Statistically

This trial is statistically notable for the setting in which its safety question was studied: a randomized, placebo-controlled human challenge model. A shared challenge protocol can create a structured context for comparing assigned groups, while the placebo arm provides a contemporaneous reference. The registry record also describes masking and parallel-group allocation, features that can help limit some sources of bias when implemented as intended.

At the same time, the available result illustrates why a count is not the same as a complete statistical comparison. The registry reports participant counts for serious and other adverse events, but it does not report a confidence interval, a formal test, or a defined analysis population. Without those elements, readers can describe the observed counts but cannot assess the precision of a comparative estimate from the registry record.

The record also raises an important endpoint issue. The primary outcome is broadly defined as participants with solicited or unsolicited adverse events, while the outcome note indicates several categories or time points and no single comparison. Safety endpoints can include many event types and collection periods. Transparent specification of the primary contrast and a stated approach to multiplicity help readers distinguish confirmatory findings from descriptive monitoring.

Finally, the study’s scope is specific. The challenge model, healthy-volunteer population, dosing schedule, and protocol-directed treatment define what the observations represent. Statistical interpretation depends on keeping that context in view rather than treating aggregate counts as universally applicable. In this record, the main contribution is the documented safety-count information and the clear limits on what can be concluded without reported comparative analyses.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record provides limited detail for interpreting the adverse-event counts. It does not break the primary endpoint into solicited and unsolicited events, identify the event types included in the other-adverse-event category, or describe severity, duration, recurrence, and timing. The serious-event term list is empty, so the record does not identify the clinical descriptions behind the serious-event summary.

The record does not report an inferential analysis of the primary outcome. It lists 0 analyses and notes that the outcome has several categories or time points and was not reduced to one comparison. There is no reported confidence interval, hypothesis test, adjusted estimate, or clearly defined analysis population. Missing-data procedures and completeness of event monitoring are also not reported.

Although the study is described as quadruple-masked and randomized, the record does not explain the randomization procedure, allocation concealment, which parties were masked, or how masking was maintained. These omissions limit assessment of possible bias. The record also does not report adherence to the assigned regimen or completion of diary and follow-up procedures.

The sample-size assumptions are described as a planning illustration based on an observed effect, not as the study’s own design justification. The registry record does not report a sample-size justification, so the adequacy of enrollment for the primary safety question cannot be assessed from this record. The study’s healthy-volunteer challenge setting further defines the scope of interpretation; generalization beyond that setting is not established by these results.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: LMN-101 in a Campylobacter Human Challenge Model — NCT04182490.
• Registry record last updated 2025-09-25; status last verified 2025-09.
• Results first posted 2025-09-25.
• 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

NCT04182490 is a completed Phase 2 randomized, quadruple-masked, parallel-group, placebo-controlled study of LMN-101 in healthy volunteers challenged with Campylobacter jejuni. The registry record reports enrollment of 42, with 21 participants at risk in each of the 3000-mg and placebo cohorts. Both regimens were described as six 500-mg capsules orally three times daily for 14 days.

The primary outcome is the number of participants with solicited or unsolicited adverse events during Day 1 to Day 14. Posted counts report 0 serious adverse events in each group, 20 participants with other adverse events in the 3000-mg cohort, and 18 in the placebo cohort; deaths are reported as 0 in both groups. The record lists 0 analyses and does not report an inferential comparison, confidence interval, missing-data method, or analysis population.

The study start date was 2022-02-21 and the primary completion date was 2022-10-04. The results should be interpreted as descriptive safety information in the study’s challenge setting.