Study to Compare the Pharmacokinetics, Pharmacodynamics, Safety, Tolerability, and Immunogenicity of Biosimilar Denosumab With Prolia® in Healthy Adult Male Volunteers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Compare the Pharmacokinetics, Pharmacodynamics, Safety, Tolerability, and Immunogenicity of Biosimilar Denosumab With Prolia® in Healthy Adult Male Volunteers (NCT05245669), a randomized phase 1 study. The primary outcome is Maximum Observed Drug Concentration (Cmax) of ENZ215 and EU- and US-sourced Prolia®.

2. Clinical Question

The study also assessed pharmacodynamics, safety, tolerability, and immunogenicity. The posted primary result concerns Cmax, a pharmacokinetic measure rather than a clinical outcome. A comparison of this endpoint can describe drug exposure under the study conditions, but it does not by itself answer questions about clinical benefit or harm. The participants were healthy adult men, so the record does not establish how the findings apply to other populations or clinical settings.

3. Trial Design

This was a phase 1, randomized, double-blind, parallel-group study with three treatment arms and a single dose. The registry lists an enrollment of 207. Participants were assigned to receive ENZ215, EU-sourced Prolia®, or US-sourced Prolia®. Each intervention was a 60-mg subcutaneous dose administered on day 1. The study is marked completed.

The primary endpoint was maximum observed drug concentration (Cmax), reported as a geometric mean in ng/ml, with geometric coefficient of variation as the dispersion measure. The endpoint timeframe is listed as 270 days. The registry description says that 24 blood pharmacokinetic samples of 2.5 mL each were collected from each subject. Sampling began with a pre-dose measurement and continued through day 270, with permitted collection windows that varied across the scheduled post-dose days. Serum denosumab concentrations were measured at a central laboratory using a validated analytical method, according to the record.

The posted primary pharmacokinetic population included participants who complied sufficiently with the protocol, received a single dose, and had one pre-dose and at least one post-dose measurement for any pharmacokinetic assessment not affected by a protocol deviation. The reported arm counts for the primary endpoint are 68 for ENZ215, 69 for EU-sourced Prolia®, and 69 for US-licensed Prolia®.

Five secondary outcomes are listed, including partial area under the concentration-time curve through day 28, time to maximum concentration, terminal elimination half-life, apparent systemic clearance, and the area under the effect curve for serum CTX-1 percent inhibition through day 270. The registry record lists 10 outcome measures overall but does not report posted analysis entries. Details such as the allocation procedure, the basis for the planned enrollment, and any interim analyses 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

Analysis population for the primary outcome, as defined in the registry: Pharmacokinetic population includes subjects who complied sufficiently with the protocol, who received a single-dose of the study drug and had 1 pre-dose and at least 1 post-dose measurement of any of the PK assessment not impacted by any protocol deviations.

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: Participants were healthy adult male volunteers between 28 to 55 years of age.

6. Primary Endpoint

The registry lists the primary outcome as Maximum Observed Drug Concentration (Cmax) of ENZ215 and EU- and US-sourced Prolia®, measured over 270 days.

Cmax is the highest measured concentration of a drug in the blood after administration. In this study, it is the maximum observed serum denosumab concentration following a single subcutaneous dose. The registry reports the endpoint as a geometric mean in ng/ml and gives geometric coefficient of variation as its measure of dispersion. The stated timeframe is 270 days, matching the period over which pharmacokinetic sampling was described.

For a pharmacokinetic comparison, Cmax describes the peak concentration reached in the observed concentration-time profile. It is used alongside other measures because exposure is not fully characterized by a single point: the secondary outcomes include concentration-time area, time to peak, half-life, and apparent clearance. General statistical context: geometric means are commonly used when measurements are positive and their distribution is asymmetric, because analysis on a logarithmic scale can make relative differences easier to model. That is a general explanation, not a statement about the analysis method used in this trial; the analysis method is not reported in the registry record.

The posted Cmax values are descriptive summaries for each arm. A formal bioequivalence assessment ordinarily requires a specified comparison and an uncertainty estimate evaluated against prespecified criteria. Those criteria, a comparison estimate, and a confidence interval are not reported in the registry record. Therefore, the arm summaries alone do not establish whether a formal bioequivalence criterion was met.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Interpreting this trial requires separating the design, the descriptive endpoint summaries, and the inferential comparison that would be needed to assess the stated bioequivalence aim. General explanations below describe statistical concepts; they do not identify methods as having been used unless the registry record explicitly says so.

What does randomization contribute?

The study is described as randomized, double-blind, and parallel-group. Randomization is intended, in general, to reduce systematic differences between treatment groups at assignment. Blinding can reduce some influences of treatment knowledge on conduct or assessment. A parallel-group design assigns participants to one arm rather than having each participant receive all study interventions. These design features do not guarantee that groups are identical in every respect, and the registry record does not describe the allocation sequence or concealment procedures.

The three arms distinguish ENZ215 from two reference-product sources: EU-sourced Prolia® and US-sourced Prolia®. Keeping these comparators separate matters because the stated study objective includes comparisons with both. The posted arm-level summaries do not provide the inferential contrasts needed to assess either comparison formally.

What do the reported summaries represent?

The primary outcome is Cmax, expressed as a geometric mean in ng/ml. A geometric mean is based on multiplicative rather than additive averaging. General statistical context: when positive measurements have a right-skewed distribution, a logarithmic transformation can produce a more symmetric distribution and support analyses of relative exposure. However, the registry record does not state whether values were transformed for analysis, what model was used, or how estimates were calculated.

The geometric coefficient of variation describes relative dispersion for the reported measurements. General context: variability affects precision; more variable measurements tend to yield less precise estimates when other design features are held constant. The arm-level dispersion figures are not a substitute for uncertainty around a comparison between arms. No confidence interval for Cmax or a treatment contrast is reported in the registry record.

What evidence would support a formal comparison?

General statistical context: an inferential comparison estimates a contrast between groups and quantifies uncertainty, often with a confidence interval. A confidence interval describes a range of values compatible with the observed data under the model and its assumptions; it is not a guarantee that the true value lies within that interval. For a bioequivalence question, the contrast and confidence interval are assessed against prespecified acceptance limits. The registry record does not report the contrast scale, confidence interval, acceptance limits, test procedure, or conclusion. The three geometric means alone cannot establish whether those criteria were met.

There are three arms, so the study objective potentially involves more than one comparison. General statistical context: when multiple hypotheses are tested, the chance of at least one false positive can increase unless the analysis plan addresses multiplicity. For equivalence questions, multiplicity and the required comparison strategy also depend on the defined objectives. The registry record does not report how comparisons were selected or whether any multiplicity procedure was planned.

How should the planning illustrations be read?

General statistical context: sample-size calculations are planning tools that describe the information a proposed design might need under stated assumptions. The planning assumptions associated with this study describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect defined as a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial was designed using them. The sample-size illustration is not observed power, and it does not establish the precision of the trial’s actual comparisons. The registry record does not report the trial’s own sample-size justification or the assumptions used to set enrollment.

Power is a design property conditional on a specified effect and analysis framework, not a post hoc measure of whether a result is convincing. General statistical context: observed power calculated from an observed effect generally conveys little beyond the result and its uncertainty. Planning estimates can help illustrate how sample size changes under alternative assumed effects, but they should not be confused with observed outcomes or with a formal conclusion.

What cannot be determined from the posted analysis information?

The registry record lists no posted analysis entries. This does not prove that no analyses were conducted; it means the inferential methods and results are not reported in the registry record. The analysis population is described for the pharmacokinetic endpoint, but a separate intention-to-treat population, per-protocol analysis set, missing-data method, covariate adjustment, and sensitivity analyses are not reported. These omissions constrain interpretation because the reported arm summaries cannot be linked to a documented model or a stated decision rule.

The endpoint description states that serum concentrations were measured using a validated analytical method and gives the sampling schedule and collection windows. Those details describe measurement, not the statistical comparison. The registry record also lists secondary pharmacokinetic and pharmacodynamic measures, but their posted values and analysis methods are not reported in the registry record. No further conclusions about them should be inferred from the primary endpoint.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures overall, including the primary Cmax outcome and five named secondary outcomes. The record does not report how many formal hypotheses were tested, which comparisons were confirmatory, whether the two reference-product arms were analyzed separately under a prespecified plan, or whether any adjustment for multiple testing was used. Those details are not reported in the registry record.

General statistical context: multiplicity matters when several outcomes or comparisons are examined because repeated testing can increase the chance of a chance-positive result. The appropriate approach depends on the purpose and structure of the comparisons. For a bioequivalence objective, the prespecified contrasts and acceptance criteria are particularly important. Neither these criteria nor a multiplicity strategy is reported in the registry record.

The registry describes the pharmacokinetic population as participants who complied sufficiently with the protocol, received a single dose, and had a pre-dose sample and at least one post-dose measurement for any pharmacokinetic assessment not impacted by protocol deviations. The endpoint counts are 68 for ENZ215, 69 for EU-sourced Prolia®, and 69 for US-licensed Prolia®. The record does not report a flow of participants from enrollment to each analysis population, the number of missing measurements by arm, or reasons for exclusion.

Missing-data handling, sensitivity analyses, and a separate intention-to-treat or per-protocol analysis are not reported in the registry record. General statistical context: missing observations can affect interpretation if their occurrence is related to treatment or measured outcomes, and different assumptions about missingness can yield different results. Without details on missingness and the analysis population for each endpoint, the robustness of the reported summaries cannot be assessed.

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 2% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: ligament rupture (1.4%).

The serious adverse event counts are 0 among 68 participants in the ENZ215 arm, 1 among 69 in the EU-sourced Prolia® arm, and 0 among 69 in the US-licensed Prolia® arm. The registry also lists ligament rupture at 1.4% among the top serious-event terms. The record does not identify that term by treatment arm in the information, so it should not be attributed to a particular arm on that basis.

These are event counts from a study of a stated single dose and a specific healthy-volunteer population. A zero count means no serious adverse events were recorded for that arm in the posted results; it does not establish that the risk is absent. The single serious event reported in one arm is a sparse observation and does not by itself establish a difference between treatments. The registry record does not report a comparative safety analysis or uncertainty interval for these counts.

Other adverse events affected 28 participants in the ENZ215 arm, 39 in the EU-sourced Prolia® arm, and 32 in the US-licensed Prolia® arm. These counts are distinct from the serious-event counts and should not be interpreted as a severity ranking. No deaths were reported in any arm. The posted counts do not establish causality, and the registry record does not report details of event timing, duration, or individual-level overlap among events.

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

The trial addresses a focused pharmacokinetic question: after a single subcutaneous dose, what maximum observed serum denosumab concentrations were reported for ENZ215 and for each Prolia® source in healthy adult male volunteers? The posted Cmax geometric means are 7663.0 ng/ml for ENZ215, 7743.0 ng/ml for EU-sourced Prolia®, and 8033.0 ng/ml for US-licensed Prolia®. These summaries describe the observed arms, with reported geometric coefficients of variation of 32.6, 23.2, and 24.9, respectively.

The record says the study was intended to demonstrate bioequivalence. It does not report the formal comparisons, confidence intervals, acceptance limits, or a bioequivalence conclusion. Therefore, the stated objective must not be confused with a demonstrated result. Descriptive proximity of arm summaries is not a substitute for an inferential comparison that accounts for uncertainty and applies prespecified criteria.

The results also do not answer whether the treatments produce the same clinical outcomes, or whether they have the same safety profile in a broader population. This was a single-dose study in healthy adult male volunteers, and Cmax is a pharmacokinetic endpoint. The registry lists pharmacodynamic and other pharmacokinetic outcomes, but their results are not reported in the available record. No conclusions about those measures can be drawn from Cmax alone.

General statistical context: a point estimate gives a central summary, while an uncertainty interval helps show how imprecisely a quantity is estimated. Without an interval for the comparison, readers cannot assess the range of contrasts compatible with the data from the posted information. The arm counts and dispersion measures add context but do not resolve that limitation.

The appropriate conclusion is narrow: the registry reports Cmax geometric means and dispersion in three study arms, along with limited safety counts. Whether a formal bioequivalence criterion was met, how precise the comparisons were, and how results extend beyond the studied participants are not reported in the registry record.

13. Why This Trial Matters Statistically

This study is statistically relevant because it illustrates the distinction between a trial’s stated objective and the evidence reported to evaluate that objective. The stated aim was to demonstrate bioequivalence among ENZ215 and EU- and US-sourced Prolia®. The posted Cmax results are arm-level geometric means, but the registry record does not include the comparative estimates, confidence intervals, or acceptance criteria needed to evaluate a formal bioequivalence conclusion.

The three-arm structure also makes comparator definition important. ENZ215 is compared conceptually with two reference-product sources, rather than with a single undifferentiated control. Each arm has its own reported Cmax summary and endpoint count. Without the planned contrast definitions and analysis output, the summaries cannot show whether each intended comparison met a prespecified criterion.

More broadly, the example highlights why precision and decision rules matter alongside point estimates. General statistical context: similar-looking estimates can still have uncertainty that is important to a decision, while different estimates may be compatible with one another when uncertainty is considered. The record does not report the uncertainty estimates needed to make that assessment.

The study also separates pharmacokinetic evidence from clinical outcomes. Cmax characterizes a feature of drug concentration after dosing; it is not itself a direct measure of patient benefit. The registry lists additional pharmacokinetic and pharmacodynamic endpoints, but their results are not reported in the available record. Careful interpretation therefore depends on keeping the posted evidence specific to the endpoint and population actually described.

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 main limitation for statistical interpretation is incomplete reporting of comparative results. Although the registry lists arm-specific Cmax geometric means, it does not report a treatment contrast, confidence interval, hypothesis test, or bioequivalence decision. The acceptance limits and prespecified analysis method are not reported in the registry record, so the stated study aim cannot be evaluated from the posted primary summaries alone.

The registry lists 10 outcome measures, but results and analysis methods for the secondary outcomes are not reported in the available record. The record also does not describe a multiplicity approach, missing-data handling, sensitivity analyses, interim analyses, or the trial’s own sample-size justification. These gaps limit assessment of the analysis plan, robustness, and completeness of outcome reporting.

The reported endpoint population is defined by protocol compliance, receipt of a single dose, and availability of specified pharmacokinetic measurements. Participant flow, reasons for exclusion, and the relationship between enrollment and endpoint counts are not detailed in the registry record. The statistical methods used to handle observations outside the stated population are not reported.

The study enrolled healthy adult male volunteers and evaluated a single 60-mg subcutaneous dose. The posted primary result is pharmacokinetic and has a stated 270-day timeframe. Generalizability beyond this population, dose, and setting cannot be established from the record. Safety interpretation is also limited by the small event counts and the absence of a reported comparative safety analysis. These limitations concern what can be concluded from the registry record; they do not establish that additional analyses or documentation do not exist elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study to Compare the Pharmacokinetics, Pharmacodynamics, Safety, Tolerability, and Immunogenicity of Biosimilar Denosumab With Prolia® in Healthy Adult Male Volunteers — NCT05245669.
• Registry record last updated 2025-12-23; status last verified 2025-12.
• Results first posted 2025-12-23.
• 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

NCT05245669 is a completed phase 1, randomized, double-blind, three-arm, parallel-group, single-dose study sponsored by Enzene Biosciences Ltd. It enrolled 207 healthy adult male volunteers. The registry lists the study start as 2022-01-10 and primary completion as 2024-05-22.

Participants received one 60-mg subcutaneous dose of ENZ215, EU-sourced Prolia®, or US-sourced Prolia®. The primary outcome was maximum observed denosumab concentration (Cmax), reported as a geometric mean with geometric coefficient of variation over a 270-day timeframe. The posted arm means were 7663.0, 7743.0, and 8033.0 ng/ml, respectively. The record also lists secondary pharmacokinetic and pharmacodynamic outcomes and provides limited adverse-event counts.

The registry describes bioequivalence as the study aim but does not report a formal comparison analysis or conclusion. Confidence intervals, acceptance criteria, and several statistical-plan details are not reported in the registry record.