A Study of Tralokinumab When Delivered Subcutaneously at Different Flow Rates to Healthy Volunteers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Tralokinumab When Delivered Subcutaneously at Different Flow Rates to Healthy Volunteers (NCT02085473), a randomized phase 1 study. The primary outcome is Area Under the Concentration-Time Curve From Zero to Infinity (AUC [0-infinity]).

2. Clinical Question

3. Trial Design

This was a completed Phase 1, randomized, open-label, parallel study of a single subcutaneous dose of tralokinumab in healthy volunteers. The registry lists an enrollment of 60. Participants were assigned among four cohorts, each described as receiving 300 mg tralokinumab in a 2 mL injection at a different flow rate. The numeric flow rates are not reported in the registry record; the cohort descriptions use the labels W, X, Y, and Z mL/min.

The registry lists the study start as 2014-03-19 and primary completion as 2014-07-10. The study status is completed. Masking is listed as none, so the record does not describe a blinded design. The randomization method, allocation concealment, and the intended allocation ratio are not reported in the registry record.

The primary objective was to evaluate pharmacokinetics and tolerability. The primary outcome was AUC from zero to infinity, derived from serum concentration measurements. The listed sampling schedule included a pre-dose sample on Day 1, collected within 30 minutes before administration, and post-dose samples on Days 2, 4, 6, 8, 10, 15, 22, 36, and 57.

In addition to the primary pharmacokinetic measure, the registry lists seven secondary outcomes, covering local injection-site symptoms and reactions, treatment-emergent adverse events, examination, vital-sign and laboratory findings, and anti-drug antibodies. These are outcome categories, not evidence that a particular event occurred. Detailed eligibility criteria, the numeric injection rates, and the study's statistical analysis plan 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.

Before assignment: A total of 149 participants were screened for the study, out of which 60 participants were randomized and completed in the study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The Pharmacokinetic (PK) population included all participants in the as-treated population with at least one detectable tralokinumab serum concentration. Here "N" signifies participants who were evaluable for this measure.

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: As-treated population included all participants who were randomized and received any study drug.

6. Primary Endpoint

The registry lists the primary outcome as Area Under the Concentration-Time Curve From Zero to Infinity (AUC [0-infinity]), measured over Day 1 (pre-dose sample collected within 30 minutes prior to study drug administration), Days 2, 4, 6, 8, 10, 15, 22, 36, and 57 post-dose.

The primary endpoint is AUC from zero to infinity, reported in day*mcg/mL. It represents the area under the curve relating serum tralokinumab concentration to time, from administration through an extrapolated infinite time. The registry defines it as AUC from zero to the last measured time plus the area from that time to infinity. It is therefore a measure of total serum exposure, rather than a single concentration at one sampling time.

Pharmacokinetic measures such as AUC are used to describe how much drug is present in the circulation over a period of time. In a study comparing injection flow rates, this endpoint can describe exposure within each delivery cohort. It does not by itself establish whether rates are equivalent or meaningfully different: that requires a prespecified comparison and an appropriate estimate of uncertainty.

The record reports a geometric mean and geometric coefficient of variation for each cohort. These summaries are appropriate for positive pharmacokinetic measurements that may vary multiplicatively. The endpoint population included as-treated participants with at least one detectable serum concentration; the reported N is the number evaluable for this measure. The sampling schedule extends through Day 57, while the endpoint's infinite-time component is estimated from the concentration-time data rather than directly observed over an infinite period.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a randomized, open-label, parallel Phase 1 study, but it does not report the detailed statistical analysis plan. The methods below explain how to read the posted summaries and distinguish them from analyses that the record does not report.

What does a geometric mean describe?

General: A geometric mean summarizes positive measurements on a multiplicative scale. It is often useful when values vary proportionally or have a right-skewed distribution. Instead of describing an arithmetic average of the raw values, it summarizes the center after values are considered on a logarithmic scale and then returned to the original scale. For pharmacokinetic exposure, this can make the central summary more representative when individual values differ by relative rather than fixed amounts.

The registry reports geometric mean AUC for each cohort. These means are descriptive: they characterize the cohort data but do not themselves compare flow rates. The record does not report a model, adjusted estimates, hypothesis tests, or confidence intervals for the cohort means.

How should the geometric coefficient of variation be read?

General: A coefficient of variation describes dispersion relative to a measure of central tendency. Its geometric form is used with geometric summaries and multiplicative variation. Larger values indicate more relative spread in the underlying measurements. It is not a confidence interval and does not show the precision of an estimated cohort mean. The posted geometric coefficient of variation values are 30.12 for Cohort 1, 25.78 for Cohort 2, 45.46 for Cohort 3, and 39.13 for Cohort 4.

Precision concerns how much an estimate might vary across repeated samples under an appropriate statistical model. A confidence interval is one common way to express that uncertainty. The registry does not report confidence intervals for these primary results, so the reader cannot use the posted summaries alone to determine a range of plausible values for each cohort mean or for differences between cohorts.

What does AUC from zero to infinity include?

The endpoint combines observed serum concentration information over time with an extrapolated terminal component. The registry defines AUC from zero to infinity as the sum of AUC from zero to the last measured time and AUC from the last measured time to infinity. Blood sampling was scheduled from the pre-dose sample on Day 1 through Day 57 post-dose. The endpoint is thus a pharmacokinetic summary of total exposure, not a direct measurement at every point in time or a clinical outcome.

General: Extrapolation is used when the full concentration-time curve cannot be observed indefinitely. The estimate relies on the observed data and the method used to characterize the terminal portion of the curve. The detailed pharmacokinetic calculation and its assumptions are not reported in the registry record. Consequently, the record does not permit an assessment of how much of the AUC estimate was extrapolated or how that component was handled.

Why do cohort summaries not establish a flow-rate effect?

The four cohorts represent different injection flow rates, but the numeric rates are not reported in the registry record. The posted results give one geometric mean and one geometric coefficient of variation for each cohort. They do not give a prespecified contrast, an estimated difference or ratio, a confidence interval for a contrast, or a statistical test. Without those elements, the summaries support description of the observed cohort results, not a formal conclusion about differences or equivalence between rates.

General: A comparative analysis should reflect the design and question, and should account for uncertainty in the estimated contrast. If the scientific question is whether exposure is sufficiently similar across delivery conditions, that requires an explicit criterion for similarity and an analysis designed to assess it. Neither such a criterion nor such an analysis is reported in the registry record. No equivalence or non-inferiority conclusion can be read from the cohort means alone.

What do the planning illustrations mean?

The stated planning assumptions describe two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. These are planning assumptions, not evidence about the study's original design. Any sample-size illustrations based on observed results are prospective planning calculations; they are not observed power and do not change the interpretation of this trial's results. The registry does not report the trial's own sample-size justification or statistical plan. The study has four cohorts, while the stated illustration assumptions refer to two arms, so those assumptions should not be mistaken for the analysis used to compare all four cohorts.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary pharmacokinetic endpoint and seven secondary outcome categories. The secondary categories include local injection-site pain and pruritus, local reactions, treatment-emergent adverse events and serious adverse events, events related to examination, vital signs or laboratory parameters, and anti-drug antibodies. The record does not report a multiplicity adjustment, a hierarchy for interpreting multiple outcomes, or a statistical analysis plan describing how multiple testing was handled.

There are 14 outcome measures listed in the record, but the posted results do not include analyses that reduce the four cohorts to one comparison. The registry reports zero analyses for the kind of comparison represented in the posted data. It would therefore be inappropriate to infer a prespecified pairwise testing strategy or to treat descriptive differences as confirmatory findings.

The primary pharmacokinetic population included participants in the as-treated population with at least one detectable tralokinumab serum concentration. The record defines N as the number evaluable for the measure. The reported Ns are 15 for Cohort 1, 15 for Cohort 2, 14 for Cohort 3, and 14 for Cohort 4. The registry does not report how missing concentrations, unevaluable participants, or incomplete sampling were handled, or whether any imputation was used.

For safety, each cohort has 15 participants listed at risk. These denominators differ from the primary endpoint's evaluable Ns in Cohorts 3 and 4. The registry record does not explain the difference, so the two outcome populations should be kept separate rather than treated as interchangeable. Details of the analysis populations for the secondary outcomes and the handling of missing safety or immunogenicity data are not reported in the registry record.

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 1% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse-event summary reports zero affected participants in each cohort. The corresponding at-risk count is 15 in each cohort, and no deaths are reported. These are observed counts in the registry's safety summary; they do not establish that serious events could not occur or that the cohorts have equivalent safety profiles.

The record also reports other adverse events for 5 participants in Cohort 1, 5 in Cohort 2, 4 in Cohort 3, and 4 in Cohort 4, with 15 at risk in each cohort. The summary does not give the event terms for these other events, their severity, timing, or relationship to treatment. It therefore cannot support a detailed characterization of the types or patterns of events.

Adverse-event counts are descriptive. Comparing counts across cohorts does not by itself account for uncertainty, and the registry reports no statistical comparison of safety outcomes by flow rate. The secondary outcome list includes several specific tolerability and safety categories, but detailed results for those outcomes are not included in the registry entries. The reported zero serious events should be read as a count for this study, not as proof of absence of risk.

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

The study provides descriptive pharmacokinetic information following a single 300 mg subcutaneous dose of tralokinumab delivered in a 2 mL injection at four different flow rates. Its primary outcome is AUC from zero to infinity, reported as a geometric mean and geometric coefficient of variation for each cohort. The results document different cohort-level summaries, with evaluable Ns reported for each group.

The results do not establish that one delivery rate produces greater or lesser exposure than another. The registry does not provide the numeric flow rates, a comparative estimate, confidence intervals for comparisons, or a reported statistical test. The cohort means should therefore be read as descriptive results, not as proof of a difference, equivalence, or non-inferiority.

The study also does not answer whether tralokinumab is effective for asthma or any other condition. The registry describes a Phase 1 study in healthy volunteers, and the primary endpoint is pharmacokinetic rather than a clinical efficacy outcome. The record lists asthma among conditions, but its stated study objective concerns pharmacokinetics and tolerability in healthy volunteers.

The safety results are limited to the counts reported in the registry summary. Zero serious adverse events and the reported counts of other adverse events are observations from this study; they do not establish the absence of risk or allow a precise comparison of flow-rate-specific safety. The registry's secondary outcome list is broader than the detailed results available in the record.

Overall, the record describes how AUC and selected adverse-event counts were reported across four cohorts. It does not report the detailed statistical plan, the numeric injection rates, or uncertainty estimates for between-cohort differences. Those omissions limit the strength and scope of conclusions that can be drawn from the posted results.

13. Why This Trial Matters Statistically

This trial addresses a statistical question about drug delivery: whether pharmacokinetic exposure and tolerability can be described when a fixed 2 mL subcutaneous injection is delivered at different flow rates. Its randomized parallel design places the delivery conditions in separate cohorts, making the cohort-level summaries relevant to that question. The study is Phase 1 and focuses on pharmacokinetics and tolerability in healthy volunteers, rather than clinical benefit.

Statistically, the record illustrates why descriptive summaries and comparative inference must be distinguished. A geometric mean characterizes the center of positive exposure measurements, while the geometric coefficient of variation describes relative dispersion. Neither summary alone provides the uncertainty around a comparison between delivery conditions. The absence of reported contrast estimates and confidence intervals means the reported cohort results are informative descriptively but cannot establish a flow-rate effect.

The study also makes the analysis population important. The primary endpoint uses participants with at least one detectable serum concentration and reports evaluable Ns, while the safety summary lists at-risk counts for each cohort. Keeping outcome-specific denominators clear prevents a reader from assuming that all measures use identical populations.

Finally, the registry's symbolic flow-rate labels and missing analysis details constrain interpretation. A result can be clinically and statistically interpretable only when the conditions, estimands, and uncertainty are sufficiently specified. The record offers cohort summaries and selected event counts, but does not report the numeric rates or a formal comparison. This makes the distinction between what was observed and what can be concluded especially important.

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 leaves several design and analysis details unreported. The numeric flow rates corresponding to W, X, Y, and Z mL/min are not reported, which prevents readers from linking the cohort results to specific delivery speeds. The randomization method, allocation concealment, and allocation ratio are also not reported. Masking is listed as none.

The primary endpoint is reported as cohort geometric means and geometric coefficients of variation, without confidence intervals or comparative analyses. The record does not specify a statistical model, the pharmacokinetic calculation details, the amount of AUC extrapolated beyond the last measurement, or the assumptions used for that extrapolation. Thus, the precision of the cohort estimates and the uncertainty in any between-cohort contrast cannot be assessed from the posted results.

The primary endpoint population consists of as-treated participants with at least one detectable serum concentration. Its evaluable Ns are 15, 15, 14, and 14, whereas the safety summary lists 15 at risk in every cohort. The registry does not explain this difference or report how missing data and incomplete sampling were handled. It also does not provide detailed results for all listed secondary outcomes.

The record does not report the trial's sample-size justification, multiplicity approach, or full statistical analysis plan. The posted adverse-event summary gives participant counts but not the terms or details of the other events. These limitations mean the available summaries describe selected outcomes but do not support a full assessment of uncertainty, comparative tolerability, or the robustness of the pharmacokinetic findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of Tralokinumab When Delivered Subcutaneously at Different Flow Rates to Healthy Volunteers — NCT02085473.
• Registry record last updated 2018-12-31; status last verified 2018-12.
• Results first posted 2018-11-23.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT02085473 is a completed Phase 1 randomized, open-label, parallel study of a single 300 mg subcutaneous dose of tralokinumab in healthy volunteers. The study enrolled 60 participants and examined delivery as a 2 mL injection at four flow rates. The numeric rates are not reported in the registry record.

The primary endpoint was AUC from zero to infinity, reported as a geometric mean and geometric coefficient of variation by cohort. Evaluable Ns were 15, 15, 14, and 14. The safety summary reports zero serious adverse events in each cohort, other adverse events for 5, 5, 4, and 4 participants, and no deaths.

The registry does not report comparative analyses, confidence intervals, the numeric injection rates, or the detailed statistical plan. The results therefore support descriptive reading of the posted cohort summaries, not formal conclusions about differences between flow rates.