This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Crossover Study to Evaluate Pegilodecakin (LY3500518) in Healthy Participants (NCT04194892), a randomized phase 1 study. The primary outcome is Pharmacokinetic (PK): Maximum Drug Concentration (Cmax) of Pegilodecakin.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04194892 |
| Phase | Phase 1 |
| Condition | Healthy Adult Subjects |
| Allocation | Randomized |
| Design model | Crossover |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Eli Lilly and Company |
| Results posted | Yes |
2. Clinical Question
Population
Healthy adult participants. The registry record reports an enrollment of 12. The primary endpoint population was randomized participants who received at least one dose and had evaluable pharmacokinetic data.
Intervention
Pegilodecakin given subcutaneously as a 0.8 mg dose at 4 mg/mL, delivered as a 0.2 mL injection from a pre-filled syringe.
Comparator
The same stated pegilodecakin dose and concentration, delivered as a 0.2 mL injection drawn from a vial into a conventional syringe.
Primary question
How do maximum pegilodecakin blood concentrations, measured as Cmax, compare after administration from a pre-filled syringe versus a vial in this single-dose crossover study?
The research question is about pharmacokinetics: the concentration reached in blood after a dose, rather than a clinical outcome. The registry describes a two-way crossover, so the comparison concerns two formulations administered across study periods. Cmax is the primary endpoint named in the record. The record also describes assessments of how quickly pegilodecakin enters the bloodstream and how long the body takes to remove it, and notes that side-effect information was collected.
This is a study in healthy participants, not a trial of treatment for a stated illness. Its stated purpose is to assess the pharmacokinetic characteristics of the two delivery formats. No clinical benefit question or patient population is described in the registry record.
3. Trial Design
The registry describes a Phase 1, randomized, open-label, single-dose, two-way crossover study. It enrolled 12 healthy adult participants and is listed as completed. The study began on 2018-01-19, with primary completion on 2018-03-14. Total participant duration was described as approximately 42 days.
Both study interventions used pegilodecakin at a dose of 0.8 mg and concentration of 4 mg/mL, administered subcutaneously in a 0.2 mL injection. The distinction was the delivery format: one was drawn from a vial into a conventional syringe, and the other was administered using a pre-filled syringe. Thus, the comparison concerns formulation and delivery presentation, not different stated doses.
In a crossover design, participants receive the study conditions in separate periods, allowing measurements under each condition to be compared within participants. This can account for stable differences between participants when estimating a treatment contrast. The registry identifies the study as randomized and crossover, but the specific sequence assignments and their counts are not reported in the registry record. The record also does not describe washout details, so no assumptions about those details are warranted.
Masking is listed as none. Participants and study personnel therefore were not described as blinded to the delivery format. That matters less for an objective laboratory concentration measurement than for a subjective outcome, but knowledge of the format can still be relevant to conduct and other assessments. The record does not give further operational details that would establish whether laboratory analyses were masked.
The primary endpoint population is defined as all randomized participants who received at least one dose and had evaluable pharmacokinetic data. The endpoint counts are 11 for the vial and 12 for the pre-filled syringe. These are formulation-specific evaluable counts in a crossover study, not evidence of two separately randomized parallel groups.
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: 2-way crossover study with 7 days washout period between doses.
Period 1
| Stage | Sequence 1 | Sequence 2 |
|---|---|---|
| STARTED | 6 | 6 |
| Received at Least 1 Dose of Study Drug | 6 | 6 |
| COMPLETED | 6 | 6 |
| NOT COMPLETED | 0 | 0 |
Period 2
| Stage | Sequence 1 | Sequence 2 |
|---|---|---|
| STARTED | 6 | 6 |
| Received at Least 1 Dose of Study Drug | 6 | 6 |
| COMPLETED | 6 | 6 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All randomized participants who received at least one dose of study drug and had evaluable PK 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.
Population: All randomized participants who received at least one dose of study drug.
| Characteristic | Unit | Sequence 1 | Sequence 2 | Total |
|---|---|---|---|---|
| Participants analysed | 6 | 6 | 12 | |
| Age, Continuous | years | 35.2 (SD 7.65) | 33.7 (SD 9.27) | 34.4 (SD 8.14) |
| Sex: Female, Male: Female | Participants | 2 | 4 | 6 |
| Sex: Female, Male: Male | Participants | 4 | 2 | 6 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 3 | 3 | 6 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 3 | 3 | 6 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 2 | 2 | 4 |
| Race (NIH/OMB): White | Participants | 4 | 4 | 8 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: United States | Participants | 6 | 6 | 12 |
6. Primary Endpoint
The registry lists the primary outcome as Pharmacokinetic (PK): Maximum Drug Concentration (Cmax) of Pegilodecakin, measured over Period 1: Days 1 to 4 and Day 8 (Predose, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 168 hours post-dose (Day 8-predose)), Period 2: Days 8 to 11 and Day 15 (Predose, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 168 hours post-dose).
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Geometric Coefficient of Variation |
| Unit | picogram per milliliter (pg/mL) |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the maximum drug concentration, or Cmax, of pegilodecakin in plasma, reported in picograms per milliliter. Cmax describes the highest measured concentration after dosing. It is one way to characterize the extent and timing of systemic exposure and can help compare how a drug is absorbed after different delivery formats.
The registry reports a geometric mean for each formulation and a geometric coefficient of variation as the measure of dispersion. Geometric means are commonly used for pharmacokinetic measurements because concentration data are often right-skewed: a smaller number of high values can pull an arithmetic mean upward. A geometric mean summarizes the central level on a multiplicative scale. The geometric coefficient of variation describes relative variability on that scale; it is not a confidence interval and does not itself show how precisely the difference between formulations has been estimated.
Cmax is only one feature of a concentration-time profile. It does not by itself describe the total exposure over time, the time to reach the maximum, or the rate of drug removal. The registry’s stated sampling schedule includes multiple post-dose times in each period, but the primary result is the maximum concentration. No confidence interval, standard error, or inferential comparison for the formulation contrast is reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary results give a geometric mean Cmax of 9050 pg/mL for pegilodecakin administered from a vial and 12000 pg/mL for administration from a pre-filled syringe. The corresponding geometric coefficients of variation are 93.7% and 111.0%. The evaluable counts are 11 and 12, respectively. These are descriptive summaries of concentrations observed under each formulation.
The reported geometric coefficients of variation indicate substantial relative variability in the measurements within each formulation group. They should not be read as uncertainty intervals around the geometric means. Without a confidence interval for the within-participant contrast, the precision of the estimated formulation difference cannot be judged directly from the reported group summaries. Nor do the two geometric means alone show whether the difference is statistically distinguishable from chance variation.
The crossover design is important to interpretation. A comparison based on paired participant-level measurements can differ from a comparison based only on two group summaries, because the pairing captures how each participant’s measurements across periods relate to one another. The registry record does not report the estimated paired contrast, its confidence interval, or a p-value. It is therefore not possible to characterize the precision or statistical evidence for a formulation contrast using the posted summaries alone.
The record reports no lower or upper confidence limits for the endpoint. It also does not report an equivalence margin or a prespecified criterion for deciding whether the formulations have sufficiently similar exposure. Consequently, the reported results cannot establish equivalence or non-equivalence. A descriptive difference in group-level geometric means is not, by itself, an equivalence assessment.
These results concern Cmax under the study conditions in healthy participants. They do not by themselves establish how the formulations compare on other pharmacokinetic measures, how they perform in a different population, or what the concentration summaries imply for clinical outcomes. The record’s purpose includes other pharmacokinetic and side-effect assessments, but the Cmax values should be interpreted as a specific concentration endpoint, not as a comprehensive measure of every aspect of exposure or safety.
9. Statistical Methods Explained
Statistical methods are only partly described in the registry record. The outcome summary uses geometric means and geometric coefficients of variation. The record identifies the population used for the primary endpoint, but a detailed analysis plan, a model for the crossover comparison, and inferential results for the contrast are not reported in the registry record.
Why report a geometric mean?
In general, concentration measurements can vary multiplicatively and may have a long upper tail. An arithmetic mean can be strongly influenced by a few high measurements. A geometric mean is calculated on a logarithmic scale and then expressed back on the original scale, so it summarizes the central level in a way suited to multiplicative variation. This is a general explanation of the statistic, not a claim about an unreported analysis step in this study.
The posted geometric means are 9050 pg/mL for vial administration and 12000 pg/mL for pre-filled syringe administration. The registry also reports geometric coefficients of variation of 93.7% and 111.0%. A coefficient of variation expresses variability relative to the scale of the measurements. It is not a confidence interval, and it does not provide the uncertainty around a between-formulation contrast. A confidence interval for the contrast would be needed to show a range of values reasonably compatible with the data and analysis.
Why does the crossover matter?
In general, crossover studies compare conditions within the same participant over separate periods. This can reduce the impact of stable participant characteristics on the contrast, because each participant serves as their own comparator. The analysis must nevertheless account for the paired structure and the period in which each formulation was administered. The registry labels this study randomized and crossover, but does not report the statistical model, sequence allocation details, or any assessment of period or carryover effects. Those details should not be inferred from the design label alone.
The endpoint counts are 11 for the vial and 12 for the pre-filled syringe. Because the study is a crossover, these counts should not be treated as two independent arm sizes without further information. The record’s endpoint population requires at least one dose and evaluable pharmacokinetic data, but it does not explain why the counts differ or provide participant-level pairing information.
What can the reported summaries establish?
Group geometric means and dispersion summaries describe the observed data. They do not supply the standard error of a paired contrast, its confidence interval, or a test of a specified hypothesis. The registry record does not report those inferential quantities for Cmax. It also does not report a prespecified equivalence margin. Therefore, no claim about statistical significance, equivalence, or the precision of the formulation contrast can be based on these summaries alone.
General statistical practice distinguishes estimation from testing. An estimate describes the size and direction of a contrast; a confidence interval describes its uncertainty; and a hypothesis test evaluates data against a stated null hypothesis. These answer related but different questions. The endpoint summaries in the registry are descriptive, and the necessary contrast estimate and uncertainty measures are not reported in the registry record.
How should planning illustrations be read?
The planning illustrations use the observed effect as a reference and consider an effect that is a stated fraction of it. Their stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For non-time-to-event outcomes, the illustrations are expressed as participants per arm; time-to-event illustrations are expressed as total events. Such values are planning illustrations, not observed power and not evidence about the probability that the study detected an effect. The registry record does not report the trial’s own sample-size justification. No planning estimate should be treated as a feature of the original design unless that is separately documented.
More generally, statistical power is a design property conditional on assumptions about the effect, variability, analysis, and sample size. It cannot be reconstructed as a useful description of the completed trial merely by inserting the observed effect. The registry does not report a rationale for the enrollment of 12 participants or a detailed protocol-based sample-size calculation.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists three outcome measures, but only the primary Cmax result is described in the available endpoint information. Secondary results are not posted in the registry record. For another endpoint, values are described as missing or not estimable for a two-arm comparison. The record does not explain the reasons for that status or give a full accounting of missing endpoint data.
The primary endpoint population includes randomized participants who received at least one dose and had evaluable pharmacokinetic data. The formulation-specific counts are 11 for vial administration and 12 for pre-filled syringe administration. The record does not report which participants lacked evaluable data, why data were unavailable, or how missing measurements were handled in an analysis. It also does not report whether any participants withdrew or whether all randomized participants completed both periods.
Multiplicity arises when several outcomes, comparisons, time points, or analyses are examined. In general, testing many hypotheses can increase the chance of at least one apparently positive result unless the analysis plan addresses that issue. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting multiple outcomes. No specific adjustment should therefore be assumed.
The full statistical analysis plan, including any planned treatment of missingness, sensitivity analyses, and multiplicity, is not reported in the registry record. The absence of those details limits assessment of whether the posted endpoint summaries correspond to all planned analyses. It does not establish that such procedures were or were not used.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Pegilodecakin Vial | 0 | 12 | 0.0% |
| Pegilodecakin Pre-filled Syringe (PFS) | 0 | 12 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Pegilodecakin Vial | 0 of 12 |
| Pegilodecakin Pre-filled Syringe (PFS) | 0 of 12 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Pegilodecakin Vial | 10 of 12 |
| Pegilodecakin Pre-filled Syringe (PFS) | 11 of 12 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Pegilodecakin Vial | Pegilodecakin Pre-filled Syringe (PFS) |
|---|---|---|---|
| Injection site reaction right upper quadrant erythema | General disorders | 5 of 12 | 5 of 12 |
| Injection site reaction right lower quadrant erythema | General disorders | 4 of 12 | 5 of 12 |
| Headache | Nervous system disorders | 4 of 12 | 5 of 12 |
| Injection site reaction right lower quadrant pruritus | General disorders | 2 of 12 | 3 of 12 |
| Nausea | Gastrointestinal disorders | 3 of 12 | 0 of 12 |
| Abdominal discomfort | Gastrointestinal disorders | 1 of 12 | 1 of 12 |
| Injection site reaction right lower quadrant hyperpigmentation | General disorders | 1 of 12 | 1 of 12 |
| Injection site reaction right upper quadrant injection site streaking | General disorders | 2 of 12 | 0 of 12 |
| Watery eyes | Eye disorders | 1 of 12 | 0 of 12 |
| Injection site reaction right lower quadrant pruritis | General disorders | 1 of 12 | 0 of 12 |
The registry reports serious adverse events for both formulation groups. There were 0 participants with serious adverse events among 12 at risk in the vial group and 0 among 12 at risk in the pre-filled syringe group. The death count is 0 in each group. These are counts over the reported study period, not estimates of risk beyond the participants and follow-up represented in this study.
For other adverse events, the registry lists 10 of 12 participants affected in the vial group and 11 of 12 in the pre-filled syringe group. These are participant counts, not counts of every individual event. A participant may experience more than one event, and these totals do not describe event frequency, duration, severity, or timing.
The record does not list serious adverse-event terms, and it does not provide detailed descriptions of the other adverse events in the information summarized. With 12 participants at risk in each group, the absence of reported serious events is a limited observation from a small study; it is not evidence that serious events cannot occur. The counts also do not establish a comparative safety difference between formulations.
12. What the Result Does, and Does Not, Mean
The registry results describe Cmax after two delivery formats in a small Phase 1 crossover study of healthy adults. The geometric mean was 9050 pg/mL for vial administration and 12000 pg/mL for pre-filled syringe administration. The geometric coefficients of variation were 93.7% and 111.0%, and endpoint counts were 11 and 12. These summaries characterize the measurements recorded for this endpoint.
They do not establish whether the formulations are equivalent, whether one produces reliably higher exposure, or whether any difference is clinically important. Such conclusions require a defined comparison, appropriate analysis of the crossover data, and uncertainty measures. A confidence interval and a prespecified equivalence margin would be particularly relevant for an equivalence question; neither is reported in the registry record.
The study concerns a single stated dose in healthy participants and reports a pharmacokinetic endpoint. It is not a direct evaluation of clinical benefit in people being treated for an illness. Cmax alone does not capture every aspect of drug exposure, and the posted values do not answer all questions about absorption, elimination, or safety.
The serious adverse-event counts are 0 among 12 at risk in each formulation group, while other adverse events were recorded for 10 of 12 and 11 of 12 participants. These descriptive counts should not be interpreted as proving absence of risk or as a definitive comparison of tolerability. The sample is small, follow-up was described as approximately 42 days, and detailed event information is not reported in the registry record.
13. Why This Trial Matters Statistically
This study illustrates why the design and summary measure both matter in pharmacokinetic comparisons. The crossover structure means measurements from the two formulations can be paired within participants. That design can be informative when participant-level responses vary, but interpreting the contrast requires an analysis that respects the pairing. Separate geometric means do not reveal the within-participant relationship.
The distinction between a geometric mean and its dispersion is also important. The geometric coefficients of variation describe variability in the observed concentrations; they are not confidence limits for the difference. Without an estimated paired contrast and its uncertainty, readers cannot assess how precise the comparison is from the registry summaries alone.
The trial also shows the limits of interpreting a small healthy-participant pharmacokinetic study as a clinical comparison. The endpoint is a concentration measure, and the registry does not report a clinical outcome or a criterion for equivalence. The result can describe exposure under the study conditions without answering whether delivery formats have the same clinical consequences.
Finally, a registry record can be useful while leaving important analytical details unresolved. The outcome definition, population, and descriptive summaries are stated, but the model, missing-data approach, multiplicity strategy, and inferential comparison are not reported in the registry record. Distinguishing reported information from unreported analysis details is essential when drawing conclusions from registry results.
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 primary limitation for interpretation is that the registry reports formulation-specific geometric means and coefficients of variation but no estimate of the paired Cmax contrast, confidence interval, or p-value. As a result, the precision of the comparison and the strength of statistical evidence cannot be assessed from the posted endpoint summaries.
The endpoint population contains 11 evaluable participants for vial administration and 12 for pre-filled syringe administration, despite an enrollment of 12. The record does not explain the unequal endpoint counts or describe missing-data handling. It also does not report participant-level data, which prevents assessment of how measurements within individuals correspond across periods.
The crossover design is identified, but the registry does not report the sequence assignments, period-specific results, washout details, or analysis model. Those omissions limit evaluation of how period effects or possible carryover were handled. Masking is listed as none, and additional details about laboratory masking are not reported.
The study involved healthy adult participants, a single 0.8 mg dose, and follow-up described as approximately 42 days. The endpoint is Cmax; the registry does not report a clinical outcome or an equivalence criterion. These features limit the questions that the posted results can address. Detailed adverse-event terms and a fuller safety analysis are also not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Crossover Study to Evaluate Pegilodecakin (LY3500518) in Healthy Participants — NCT04194892.
- Registry record last updated 2026-07-13; status last verified 2026-07.
- Results first posted 2026-07-13.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT04194892 is a completed, randomized, open-label, Phase 1 crossover study of pegilodecakin administered as a single subcutaneous dose from a vial or a pre-filled syringe in healthy adults. The registry reports enrollment of 12 and participant duration of approximately 42 days.
The primary endpoint was maximum drug concentration, Cmax, measured in pg/mL. The geometric mean was 9050 for vial administration and 12000 for pre-filled syringe administration; geometric coefficients of variation were 93.7% and 111.0%. Endpoint counts were 11 and 12.
The registry reports 0 serious adverse events among 12 at risk in each group. Other adverse events affected 10 of 12 participants in the vial group and 11 of 12 in the pre-filled syringe group. An inferential comparison, confidence interval, detailed statistical analysis plan, and missing-data approach are not reported in the registry record.