To Compare the PK and Safety of Omalizumab (CT-P39, EU-approved Xolair, and US-licensed Xolair) in Healthy Subjects: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for To Compare the PK and Safety of Omalizumab (CT-P39, EU-approved Xolair, and US-licensed Xolair) in Healthy Subjects (NCT04018313), a randomized phase 1 study. The primary outcome is Pharmacokinetic Outcome Measures [AUC0-inf] for Part 2.

2. Clinical Question

3. Trial Design

This was a Phase 1 randomized, parallel-group, single-dose study in healthy subjects, with three formulations of omalizumab evaluated across two parts. The registry reports enrollment of 176. The listed Part 1 arms were CT-P39 and EU-approved Xolair; the listed Part 2 arms were CT-P39, EU-approved Xolair, and US-licensed Xolair. Each arm description specifies a 150 mg/mL solution for injection in a prefilled syringe.

The registry’s official title describes the study as double-blind, while its masking designation is quadruple. Those are both descriptions in the record; further details about who was masked and how masking was maintained are not reported in the registry record. Random allocation and a parallel-group model are recorded. The method used to generate the allocation sequence, allocation concealment, and the planned group allocation proportions are not reported in the registry record.

The primary pharmacokinetic measure was AUC0-inf in Part 2, with a timeframe up to day 127. The primary analysis population is defined as the pharmacokinetic set: randomly assigned subjects who received a complete dose and provided at least one post-treatment serum concentration above the lower limit of quantification for omalizumab. This population definition means that the primary result is not necessarily based on every enrolled subject. The registry also lists pharmacokinetic and pharmacodynamic secondary outcomes, including half-life and measures involving free or total IgE.

The record reports a completed study. The original sample-size justification and the trial’s original statistical design assumptions are not reported in the registry record. In particular, the record does not state a planned detectable difference or the original power calculation.

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

Analysis population for the primary outcome, as defined in the registry: PK set: all randomly assigned subjects who receive a complete dose of study drug and provide at least one post-treatment serum concentration above the lower limit of quantification for omalizumab.

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: ITT set: all subjects enrolled and randomly assigned to receive a dose of any study drug, regardless of whether or not any study drug was administered.

6. Primary Endpoint

The registry lists the primary outcome as Pharmacokinetic Outcome Measures [AUC0-inf] for Part 2, measured over up to day 127.

The primary endpoint was AUC0-inf for Part 2, measured in day*μg/mL, with a timeframe up to day 127. AUC is the area under a concentration-time curve. In general, it represents drug exposure over time; the “from time zero to infinity” definition extends the exposure estimate beyond the final observed measurement using an extrapolation specified by the analysis. The registry does not report the details of that extrapolation.

Comparing AUC across formulations is a way to assess whether their measured pharmacokinetic exposure is similar. This is useful when the study question concerns formulation comparison rather than a clinical response in people with a disease. AUC does not directly measure symptom improvement, disease control, or other clinical outcomes. The study enrolled healthy subjects, and the primary outcome is a laboratory-based pharmacokinetic measure.

The registry describes the primary outcome as a mean with standard deviation. It also records sponsor analyses expressed as ratios of geometric least-squares means. These are different summaries: an arithmetic mean difference describes an absolute separation between group means, while a ratio describes relative values on a multiplicative scale. The registry labels the ratio analyses as equivalence analyses, but the equivalence boundaries and the full statistical method are not reported in the registry record. Therefore, the endpoint can be described and the posted comparisons can be read, but the registry alone does not establish the criteria used to make an equivalence decision.

7. Results Posted in the Registry

• EU-approved Xolair (Part 2): mean 897.70 versus 910.90 on control; difference -13.20 (95% CI -123.68 to 97.28), standardized effect d = -0.05; z-test p = 0.815.
• US-licensed Xolair (Part 2): mean 926.30 versus 910.90 on control; difference 15.40 (95% CI -95.14 to 125.94), standardized effect d = 0.06; z-test p = 0.785.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Pharmacokinetic Outcome Measures [t1/2] for Part 1& Part 2

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • EU-approved Xolair (Part 1): mean 28.77 versus 29.75 on control; difference -0.98 (95% CI -4.22 to 2.26), standardized effect d = -0.22; z-test p = 0.553.
  • CT-P39 (Part 2): mean 29.30 versus 29.75 on control; difference -0.45 (95% CI -3.85 to 2.95), standardized effect d = -0.05; z-test p = 0.795.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between EU-approved Xolair (Part 1) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CT-P39 (Part 2) and the control. The interval gives the range of effects that remain compatible with the data.

Pharmacodynamics Outcome Measures [Cmin of Free IgE] for Part 1 & Part 2

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • EU-approved Xolair (Part 1): mean 3.46 versus 3.15 on control; difference 0.31 (95% CI -0.74 to 1.35), standardized effect d = 0.24; z-test p = 0.565.
  • CT-P39 (Part 2): mean 3.53 versus 3.15 on control; difference 0.37 (95% CI -0.43 to 1.17), standardized effect d = 0.27; z-test p = 0.360.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between EU-approved Xolair (Part 1) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CT-P39 (Part 2) and the control. The interval gives the range of effects that remain compatible with the data.

Pharmacodynamic Outcome Measures [Cmax of Total IgE] for Part 1 & Part 2

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • EU-approved Xolair (Part 1): mean 165.20 versus 241.53 on control; difference -76.33 (95% CI -176.94 to 24.27), standardized effect d = -0.54; z-test p = 0.137.
  • CT-P39 (Part 2): mean 245.24 versus 241.53 on control; difference 3.71 (95% CI -98.44 to 105.86), standardized effect d = 0.02; z-test p = 0.943.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between EU-approved Xolair (Part 1) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between CT-P39 (Part 2) and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes span pharmacokinetics and pharmacodynamics. They include time to maximum concentration, half-life, minimum free IgE, time to minimum free IgE, maximum total IgE, and time to maximum total IgE. Across the posted summaries, comparisons cover Part 1 and Part 2, with the available numerical summaries showing variation in estimates and uncertainty rather than a single uniform pattern across every measure. Numerical results for some of the named secondary outcomes are not reported in the registry record.

These measures complement the primary AUC endpoint by describing other aspects of concentration over time or pharmacodynamic response. Half-life concerns the decline in concentration; time-to-maximum measures concern when a peak occurs; IgE measures describe pharmacodynamic quantities. They are related to the study’s formulation-comparison question but do not answer the same question as AUC0-inf. The primary result is therefore best read as one part of a broader profile, not as a summary of every secondary measure.

The recalculated secondary comparisons are unadjusted, and multiple outcomes and comparisons create opportunities for chance findings. Unless a multiplicity strategy is specified, individual secondary p-values should be treated as exploratory rather than as a collection of confirmatory tests. The statistical plan for handling multiplicity is not reported in the registry record. The secondary results can help describe patterns and identify questions for further evaluation, but they carry less weight than the designated primary endpoint for a confirmatory conclusion.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Pharmacokinetic Outcome Measures [Tmax] for Part 1& Part 2
• Pharmacokinetic Outcome Measures [t1/2] for Part 1& Part 2
• Pharmacodynamics Outcome Measures [Cmin of Free IgE] for Part 1 & Part 2
• Pharmacodynamic Outcome Measures [Tmin of Free IgE] for Part 1 & Part 2
• Pharmacodynamic Outcome Measures [Cmax of Total IgE] for Part 1 & Part 2
• Pharmacodynamic Outcome Measures [Tmax of Total IgE] for Part 1 & Part 2

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: each participant contributes a measured AUC value, and the registry summarizes each arm using a mean and standard deviation. The mean describes the group’s average AUC. The standard deviation describes the spread of individual values around that average; it is not the uncertainty in the mean and is not a confidence interval.

What does a mean difference represent?

A mean difference subtracts one group’s arithmetic mean from another’s. Its sign depends on the order of subtraction. The recalculated comparison of EU-approved Xolair with CT-P39 is -13.2 day*μg/mL, meaning the posted EU-approved Xolair mean is lower on that arithmetic scale. The comparison of US-licensed Xolair with CT-P39 is 15.4 day*μg/mL, meaning the posted US-licensed Xolair mean is higher. These are simple unadjusted recalculations from the group summaries, not the registry’s sponsor model.

What does a confidence interval add?

A confidence interval gives a range of estimates compatible with the observed data under the method used. In general, wider intervals indicate less precision, while narrower intervals indicate greater precision. For the two recalculated primary comparisons, the 95% intervals include zero and extend to values on both sides of it. That means the summaries do not precisely resolve the direction or size of an arithmetic mean difference. The interval does not state the probability that the true difference lies within its bounds, and it does not establish that any difference within the interval would be clinically or pharmacokinetically acceptable.

How should the p-values be read?

The recalculated p-values are unadjusted tests of a zero arithmetic mean difference under the calculation’s assumptions. A p-value describes how unusual the observed result, or a more extreme result, would be if the null model were true. It is not the probability that the null hypothesis is true, and it does not measure the probability that the formulations are equivalent. A non-small p-value does not prove there is no difference; it can reflect uncertainty, including uncertainty from limited information.

How does the registry’s ratio analysis differ?

The registry reports ratios of geometric least-squares means rather than arithmetic mean differences. A ratio expresses a relative comparison, whereas a difference expresses an absolute separation. Geometric summaries are often useful for measurements with multiplicative variation or right-skewed distributions (general statistical context), but the actual distributional checks, model, transformation, and adjustment details used in this trial are not reported in the registry record. The ratio results have 90% confidence intervals and are labelled as equivalence analyses. A formal equivalence assessment requires prespecified boundaries and a decision rule. Those boundaries and the detailed method are not reported, so the ratios and their intervals can be quoted but the equivalence conclusion cannot be independently reconstructed from the registry record.

What do the recalculations leave out?

The unadjusted recalculations use arm-level means, standard deviations, and analysis counts. They do not account for covariates, a fitted model, transformations, or other design features unless those are already reflected in the posted summaries. No adjustment is made for multiple comparisons in these recalculations. This makes them useful as transparent descriptive comparisons, but they should not be mistaken for the sponsor’s prespecified analysis. The registry does not report enough detail to reproduce the sponsor model.

For continuous outcomes, over-dispersion means that observations vary more than a chosen model expects. In general, ignoring such extra variation can make standard errors too small and confidence intervals too narrow. Whether over-dispersion was assessed or relevant to the sponsor’s primary analysis is not reported in the registry record. The posted standard deviations show that there is variation among subjects, but they do not identify the model used for the reported ratio results.

11. Confidence Intervals and Precision

The unadjusted 95% confidence interval for the CT-P39 versus EU-approved Xolair mean difference runs from -123.7 to 97.28 day*μg/mL. The interval for CT-P39 versus US-licensed Xolair runs from -95.14 to 125.9 day*μg/mL. Both include zero and contain values in both directions. Thus, the data are compatible with a range of possible arithmetic mean differences, rather than yielding a precise estimate of the direction or magnitude. A confidence interval including zero is not proof that the groups are identical.

Precision depends on the amount of information and the variability in the outcome. The posted standard deviations are substantial relative to the estimated mean differences, and the intervals remain broad. This description concerns the simple comparisons calculated from the posted summary statistics; it does not characterize the sponsor’s model-based uncertainty in the same way, because the sponsor analysis uses geometric least-squares means and 90% intervals.

The sponsor-reported 90% intervals are 95.91 to 116.31 for the CT-P39 to EU-approved Xolair ratio, 89.76 to 108.58 for the CT-P39 to US-licensed Xolair ratio, and 85.09 to 102.68 for the EU-approved to US-licensed Xolair ratio. These intervals describe uncertainty for the reported ratios. The registry labels the analyses as equivalence analyses, but does not report the equivalence bounds or the method needed to judge whether each interval met the relevant criteria. Interval precision and an equivalence determination are related but not interchangeable: precision describes uncertainty, while equivalence also requires defined acceptable limits.

The registry does not report a clinically meaningful threshold for AUC. It is therefore not possible to use these intervals to determine whether all plausible differences are negligible for a clinical purpose. Further, these are pharmacokinetic comparisons in healthy subjects, not direct estimates of a patient-centered outcome.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are expressed as participants per arm, not as total events. They are illustrations based on the observed effect in the recalculated comparison, not the trial’s original design. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect to detect set at the stated fraction of the observed effect. The original design assumptions and original sample-size justification are not reported in the registry record.

The 80% power column gives the illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect under those assumptions, if that effect and model assumptions were true. The 90% column gives the corresponding illustrative number for a 90% chance. These are planning calculations, not a guarantee that a future study will achieve that power or detect an effect.

For the primary comparison with EU-approved Xolair, the illustration for 100% of the observed effect is 6,779 participants per arm for 80% power and 9,076 per arm for 90% power. For the comparison with US-licensed Xolair, the corresponding figures are 5,037 and 6,742 participants per arm. When the assumed effect is reduced to 75% or 50% of the observed effect, the figures increase. Smaller effects are harder to distinguish from random variation, so they require more participants under the same assumptions. The curves represent this relationship between the assumed effect size and the planning requirement. This is not observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -13.200; pooled standard deviation σ = 274.307.
2. n = 2 × (1.96 + 0.842)² × 274.307² / -13.200² = 6,779.0, rounded up to 6,779 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -13.1999999999999                      # observed difference in means
sigma <- 274.30731961939                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(4018313)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 6,779 (80% power), 9,076 (90% power)
 75% of observed effect: n per arm = 12,052 (80% power), 16,134 (90% power)
 50% of observed effect: n per arm = 27,116 (80% power), 36,301 (90% power)
power.t.test: 6779.9 
Simulated power at n = 6,779 per arm: 0.801 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The registry’s sponsor-reported primary analyses compare ratios of geometric least-squares means. They report a ratio of 105.62, with a 90% confidence interval from 95.91 to 116.31, for CT-P39 versus EU-approved Xolair; 98.72, with an interval from 89.76 to 108.58, for CT-P39 versus US-licensed Xolair; and 93.47, with an interval from 85.09 to 102.68, for EU-approved Xolair versus US-licensed Xolair. The registry labels these as equivalence analyses.

The recalculations instead use the posted arithmetic means and standard deviations to estimate unadjusted mean differences and 95% confidence intervals. They do not reproduce the sponsor analysis: the estimand, scale, and interval level differ. The recalculated tests are helpful as a transparent check on the group summaries, but they should not replace the sponsor’s own analysis in interpreting the intended primary comparison.

The registry does not report the sponsor model, the equivalence margins, or the decision criteria. Consequently, the recorded equivalence labels cannot be independently assessed from the registry record alone. The reported ratios and intervals can be described, while any claim that a specific equivalence criterion was met would require information not reported in the registry record.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and multiple secondary outcomes, and the posted analyses include more than one comparison. Testing several outcomes or contrasts increases the chance of obtaining at least one apparently unusual result by chance if each is judged separately. Statistical approaches can control or otherwise account for this issue, but the multiplicity procedure planned for this trial is not reported in the registry record. The recalculated p-values are unadjusted and should be read as individual comparisons, not as multiplicity-controlled evidence.

The primary pharmacokinetic population is defined in the registry as randomly assigned subjects who received a complete dose and had at least one post-treatment serum concentration above the lower limit of quantification for omalizumab. This is a post-randomization analysis-set definition. The registry does not report the full participant flow into each analysis, reasons for exclusion, or whether the sponsor conducted other population analyses. It is therefore not possible from this record to evaluate how the primary-set exclusions may have affected comparability.

Missing-data methods, rules for handling measurements below the lower limit of quantification, and treatment of incomplete concentration-time profiles are not reported in the registry record. These details matter for pharmacokinetic measures because AUC estimation uses measurements across time and the primary analysis set requires at least one qualifying post-treatment concentration. The record also does not report whether sensitivity analyses tested alternative assumptions about missing or unquantifiable measurements.

The sponsor’s model and detailed statistical analysis plan are not reported in the registry record. The record does not specify the model covariates, transformations, handling of protocol deviations, or whether interim analyses occurred. These details should not be inferred from the reported means or ratio estimates. Without them, the registry supports a description of the posted results but a limited assessment of the full prespecified analysis strategy.

16. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: head injury (2.1%).

The registry reports serious adverse event counts by arm. In Part 1, no serious adverse events were reported for CT-P39 or EU-approved Xolair. In Part 2, one serious adverse event was reported among 47 subjects at risk in the CT-P39 arm; none were reported among 49 at risk in the EU-approved Xolair arm or 50 at risk in the US-licensed Xolair arm. No deaths were reported in any listed arm. The record lists Head injury at 2.1% among the top serious-event terms.

These are counts over the reported safety groups, not estimates of a causal treatment effect. A serious adverse event is a safety classification; the record does not establish that an event was caused by the study drug. The groups are modest in size, and sparse event counts provide limited precision for comparing uncommon harms. Zero reported events in an arm does not establish that the risk is zero.

The trial was conducted in healthy subjects and was a single-dose study. Its safety summaries therefore describe the reported events in this study context and do not by themselves characterize safety in other populations or with other use patterns. Further details about event definitions, follow-up for safety, and causal assessments are not reported in the registry record.

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

The results describe a randomized comparison of three omalizumab formulations in healthy subjects, focused on pharmacokinetic exposure and safety after a single dose. In Part 2, the arithmetic mean AUC values were close in magnitude, and the simple unadjusted confidence intervals for the mean differences included zero. The registry also reports geometric least-squares-mean ratios with 90% intervals and labels those analyses as equivalence analyses.

These observations do not mean that the formulations are identical. The recalculated intervals retain uncertainty about the size and direction of an arithmetic mean difference. Nor can the sponsor’s equivalence labels be independently checked without the equivalence margins, detailed model, and decision rule, which are not reported in the registry record. A failure to show a difference is not the same as demonstrating equivalence; formal equivalence assessment requires a defined acceptable range and a suitable analysis.

The primary endpoint is a pharmacokinetic measure, not a clinical measure of symptoms, function, or disease outcomes. Participants were healthy subjects, so the study does not directly describe effectiveness or safety in people with a particular condition. The registry record does not report evidence about long-term outcomes from this single-dose comparison.

The safety counts are also descriptive. The small number of serious events and the absence of reported events in some arms should not be interpreted as proof of no risk or as a reliable ranking of formulations. In statistical terms, the record supports careful description of measured exposure and observed events, while leaving important questions about clinical meaning, equivalence criteria, and generalizability unresolved.

18. Why This Trial Matters Statistically

This study illustrates why the statistical scale and analysis matter in formulation comparisons. Arithmetic mean differences and ratios of geometric least-squares means may both summarize group contrasts, but they answer questions on different scales. A mean difference is an absolute contrast; a ratio is relative. Their estimates and intervals should not be treated as interchangeable, and a recalculation from summary statistics cannot reproduce a model-based sponsor analysis without the model details.

It also shows why a non-significant difference is not enough to claim equivalence. The unadjusted confidence intervals include zero, but that only indicates that the data do not clearly resolve a nonzero arithmetic mean difference under the recalculation. Equivalence requires prespecified acceptable bounds and an analysis designed to evaluate them. Although the registry labels its ratio analyses as equivalence analyses, the bounds and decision criteria are not reported in the registry record.

Finally, the trial distinguishes pharmacokinetic evidence from clinical evidence. AUC describes exposure, and the secondary outcomes add other pharmacokinetic or pharmacodynamic information. These are relevant measurements for comparing formulations, but they do not directly establish patient benefit or long-term safety. The study’s Phase 1, single-dose setting in healthy subjects and its reported analysis population define the scope of what the results can address.

For biostatistical interpretation, the key lesson is to keep the estimand, population, scale, uncertainty, and decision rule connected. The posted summary statistics enable transparent unadjusted comparisons, while the registry’s incomplete reporting of the sponsor method and equivalence criteria limits independent evaluation of the formal primary analysis.

19. 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.

This is a Phase 1 single-dose study in healthy subjects, so its population and setting do not directly represent people treated for a disease or repeated-dose use. Its primary outcome is pharmacokinetic exposure rather than a clinical outcome. These features limit what can be concluded about patient-centered benefit and longer-term effects.

The sponsor analysis is reported as ratios of geometric least-squares means, but the model details and equivalence margins are not reported in the registry record. This prevents independent evaluation of the formal equivalence decision. The simple recalculations use arithmetic means and standard deviations and are unadjusted; they provide a separate descriptive perspective, not a reproduction of the sponsor’s intended analysis.

The primary analysis set excludes randomly assigned subjects who did not meet the complete-dose and post-treatment concentration criteria. The registry does not provide enough detail to assess the reasons for any exclusions or how missing and unquantifiable values were handled. The planned multiplicity strategy for the secondary outcomes is also not reported in the registry record.

Although enrollment is reported as 176, that overall figure does not substitute for outcome-specific analysis counts. The primary Part 2 arms have reported analysis counts of 46, 49, and 50, and those counts define the summaries used for the primary endpoint. The safety groups use their own at-risk counts. The results should be interpreted using the relevant analysis population for each measure rather than assuming that every outcome uses the same participants.

Finally, the safety data contain few serious events. Sparse counts limit precision, and zero events in an arm cannot establish an absence of risk. Detailed safety follow-up and causal assessments are not reported in the registry record.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: To Compare the PK and Safety of Omalizumab (CT-P39, EU-approved Xolair, and US-licensed Xolair) in Healthy Subjects — NCT04018313.
• Registry record last updated 2023-05-11; status last verified 2021-09.
• Results first posted 2023-05-11.
• 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.

23. Record Summary

The registry describes a completed Phase 1, randomized, parallel-group, single-dose study comparing CT-P39, EU-approved Xolair, and US-licensed Xolair in healthy subjects. The primary endpoint was Part 2 AUC0-inf through day 127 in the pharmacokinetic set. The posted arithmetic means were 910.9, 897.7, and 926.3 day*μg/mL, respectively.

Unadjusted recalculations of the two CT-P39 comparisons produced mean-difference confidence intervals that included zero. The registry separately reports geometric least-squares-mean ratios and labels those analyses as equivalence analyses, but the equivalence margins and detailed method are not reported in the registry record. Serious adverse event counts were low, with no deaths reported. The findings concern measured pharmacokinetic and safety outcomes in this study setting; they do not directly answer clinical-outcome questions.