Pharmacokinetics and Safety of Cefazolin 3gm DUPLEX in Adults: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pharmacokinetics and Safety of Cefazolin 3gm DUPLEX in Adults (NCT05205486), a na phase 1 study. The primary outcome is Cefazolin Plasma Concentration Following Infusion.

2. Clinical Question

The study was designed to examine cefazolin concentrations in adults weighing >= 120 kg who were scheduled for surgery. Its primary question was whether concentrations after a single 3gm dose delivered from a DUPLEX container could be evaluated in this population using the validated Cefazolin PK Model described in the study summary. The summary says the model would be used to assess whether there were significant pharmacokinetic changes within the study population.

This design addresses measurement of drug concentration after dosing in a specified surgical population. It does not, by itself, compare outcomes between different treatments or establish a causal difference from an untreated or differently treated group. The main statistical interpretation therefore depends on the actual concentration observations, their variability, and the completeness of sampling. Those numerical results are not reported in the registry record. The study summary specifies five planned blood-sampling times, while also noting that only one participant agreed to the 8-hour pharmacokinetic blood sample. The record does not provide enough information to reconstruct the observed concentration profile or determine how the incomplete late sampling affected the analysis.

3. Trial Design

This was a completed Phase 1, open-label, single-group study. The registry record reports enrollment of 12 participants, with no randomized allocation and no masking. All participants were assigned to the Cefazolin 3gm Injection group; there was no like-for-like control group. The study began on 2022-04-05 and had a primary completion date of 2023-07-13. The sponsor was B. Braun Medical Inc.

The intervention was Cefazolin 3gm for Injection USP and Dextrose Injection USP, described as a single intravenous infusion over 30 minutes. The arm description says the infusion started approximately 0.5 hours before surgery began and followed institutional guidelines on the day of surgery. The study summary describes five pharmacokinetic blood samples per subject, collected up to 8 hours after dosing. The primary outcome description identifies sampling at 0.5, 1, 2, 4, and 8 hours after the start of infusion. It also states that only one participant agreed to the 8-hour pharmacokinetic blood sample.

Because the trial had one group, its design can characterize measured concentrations among participants who received the study dose, but it cannot estimate a between-group treatment contrast. Open-label status means treatment assignment was not masked; the record does not describe additional measures to limit potential measurement or reporting influences. No comparator, allocation procedure, or blinding procedure beyond the reported design is described.

The registry record labels the study completed. It does not report the statistical analysis plan, enrollment rationale, detailed eligibility criteria, or analysis populations. The summary says concentrations would be assessed using a validated Cefazolin PK Model to verify that there were no significant pharmacokinetic changes within the study population, but the model specification and its results are not reported in the registry record. The design description should therefore be read as evidence of the study's stated objective and sampling plan, not as evidence of the outcome of the model assessment.

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: There were no pre-assignment activities for this study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Only one (1) subject agreed to the 8-hour PK blood sample.

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.

6. Primary Endpoint

The registry lists the primary outcome as Cefazolin Plasma Concentration Following Infusion, measured over 8 hours.

The primary endpoint is titled “Cefazolin Plasma Concentration Following Infusion.” It is a continuous measurement in ug/mL, summarized as a mean with standard deviation, with an 8-hour timeframe. Plasma concentration measures the amount of drug present in the sampled blood compartment at specified times. Pharmacokinetic studies use such measurements to describe how concentrations change after administration and to assess whether observed profiles are consistent with a model or expectation.

The registry description specifies five sampling times: 0.5 hours, identified as the end of infusion, and 1, 2, 4, and 8 hours after the start of study drug infusion. The study summary describes these samples as inputs for assessment with the validated Cefazolin PK Model. The record says only one participant agreed to the 8-hour pharmacokinetic blood sample, so the late observation is especially limited in its ability to characterize the group. The number of participants contributing measurements at each earlier time and the handling of missing samples are not reported in the registry record.

A mean gives a summary of the observed concentration at a time point, while the standard deviation describes the spread of individual measurements around that mean. These summaries answer different questions: the mean characterizes the group average, and the standard deviation characterizes participant-to-participant variability. Neither alone establishes how precise a mean estimate is; that assessment also depends on the number and pattern of observed measurements. The registry record does not report the actual means, standard deviations, confidence intervals, or model-based estimates. Consequently, the endpoint definition and intended use can be described, but the magnitude and precision of the observed concentrations cannot be interpreted from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a continuous variable: plasma cefazolin concentration in ug/mL. The registry record specifies the mean as the summary parameter and the standard deviation as the measure of dispersion. These are descriptive statistics. The mean locates the average observed concentration, while the standard deviation indicates how much individual measurements vary around that average. They should not be conflated: a large or small standard deviation describes the observations, not the precision of the estimated mean by itself.

General statistical explanation: a confidence interval expresses a range of values compatible with the data and the method used to construct the interval. Its width reflects uncertainty in the estimate under that method. A confidence interval is not reported for the primary endpoint in the registry record. Without the estimate, the sample information contributing to it, and a stated inferential procedure, no interval can be reconstructed or interpreted.

The summary describes a plan to assess concentrations with a validated Cefazolin PK Model. Model-based pharmacokinetic analysis can use the pattern of concentration measurements over time to characterize a concentration profile, while accounting for the structure specified by the model. The model name alone does not identify its equations, parameters, fitting method, assumptions, or criteria for judging a change. Those details, along with model estimates and uncertainty measures, are not reported in the registry record. The stated intention to use a validated model should therefore not be confused with a report of its fit or findings.

Sampling time is central to interpretation of a concentration profile. The planned times were 0.5 hours, described as the end of infusion, and 1, 2, 4, and 8 hours after the start of infusion. These measurements are repeated observations on participants over time, rather than independent treatment groups. A complete interpretation would require knowing which participants provided samples at each time, whether sample collection followed the planned schedule, and how incomplete observations were handled. The registry record notes that only one participant agreed to the 8-hour pharmacokinetic blood sample, but does not report the observed sample counts at the other times or the statistical handling of missing measurements.

General statistical explanation: repeated measurements from the same participant are related. Analyses that treat those measurements as independent can misrepresent uncertainty because within-person observations may be correlated. A longitudinal or pharmacokinetic model can represent that structure, but the specific method must be known before its estimates can be assessed. The registry record does not report whether the endpoint summaries were calculated separately at each time, whether a repeated-measures approach was used, or how participant-level dependence was incorporated into the model.

Variability also matters when interpreting concentration data. General statistical explanation: over-dispersion means observed variation is greater than a model or analysis expects. When that occurs, uncertainty estimates based on the narrower variability assumption can be too small. An appropriate model may account for extra variability, but the registry record does not report a dispersion assessment or the model's treatment of variability. No conclusion about over-dispersion or the adequacy of the variability model can be drawn from the endpoint description alone.

The record lists 40 outcome measures and zero analyses. These registry counts do not establish which analyses were performed, whether outcome measures were grouped or evaluated separately, or whether any results were submitted. The primary endpoint is identified, but the statistical analysis plan, any adjustment for multiple testing, and the decision rules for interpreting results are not reported in the registry record. Such omissions matter because choices about outcomes, models, time points, and multiplicity can affect the meaning of statistical estimates.

A sample-size planning illustration is conceptually different from the study's enrollment and its observed findings. The stated illustration assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. It specifies participants per arm for non-time-to-event outcomes. Those assumptions do not describe this single-group study, which has no two-arm randomized comparison. The numerical observed effect needed to interpret such planning quantities is not reported in the registry record. Any planning estimate is therefore an illustration under stated assumptions, not a result from the trial and not observed power. The registry record does not report a sample-size justification for the study's own design.

In general, statistical significance and practical importance are distinct. A significance test, if used, addresses compatibility with a specified null model under stated assumptions; it does not by itself describe the size or precision of an effect. Here, the registry record does not report the endpoint estimates, uncertainty intervals, test results, or detailed analysis specification. Interpretation should remain focused on what is documented: the intended continuous concentration measurement, the stated sampling schedule, and the absence of reported numerical endpoint results.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 40 outcome measures, including the primary concentration endpoint and secondary safety and hematology outcomes. It also reports zero analyses. These registry counts do not reveal which outcomes were analyzed, how many comparisons were made, or whether tests were conducted at multiple time points. The record does not report a multiplicity strategy, such as prioritization rules or adjustment of significance thresholds. It is therefore not possible to assess how the study controlled the chance of false-positive findings across multiple analyses.

Missing data are relevant to the concentration endpoint because the planned schedule included five time points and the record states that only one participant agreed to the 8-hour pharmacokinetic blood sample. The number of missing observations at other times, reasons for missingness, and any imputation or model-based handling are not reported in the registry record. The available information does not establish whether the endpoint analysis used complete cases, partial profiles, or another approach. Missingness can affect both the amount of information available and the conclusions supported by the data, especially when it is related to participant or measurement characteristics.

The registry record reports enrollment of 12 participants but does not define the analysis populations, describe exclusions, or state how many participants contributed to each endpoint analysis. It does not report whether analyses followed a prespecified intention-to-treat, per-protocol, or other population definition. Such labels should not be inferred from the single-group design or the enrollment count. Because the statistical analysis plan and outcome-level results are not reported, the handling of missing data, multiplicity, and analysis populations remains uncertain.

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 0% reporting threshold.

The registry record reports that 12 participants were at risk for serious adverse events in the Cefazolin 3gm Injection group and that 0 were affected. It also reports 12 participants at risk for other adverse events and 0 affected. The reported number of deaths is 0, and no serious adverse event terms are listed.

These counts describe what is recorded for this study group; they do not compare safety with another treatment because there was no comparator group. A zero count in this study is not proof that an event cannot occur. The amount of information available to characterize uncommon events is limited by the number of participants and the study's observation experience. The registry record does not report detailed event definitions, follow-up duration for safety, severity or relatedness assessments, or a narrative explaining the absence of listed events. It also does not provide the full results for each hematology outcome. The safety figures should therefore be read as the registry's reported counts, not as a comprehensive estimate of risk or as a comparative safety conclusion.

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

The trial's statistical contribution, as described in the registry record, is its planned assessment of plasma cefazolin concentrations after a single 3gm infusion in adults weighing >= 120 kg who were scheduled for surgery. The record identifies a mean concentration endpoint, a standard deviation summary, and sampling times extending to 8 hours after infusion began. It reports that only one participant agreed to the 8-hour pharmacokinetic sample. These details establish the study question and an important constraint on late-time information, but they do not provide the measured concentration profile.

The registry record does not report primary endpoint estimates, standard deviations, confidence intervals, or results from the stated Cefazolin PK Model assessment. It is therefore not possible to describe the level of concentrations, the variability among participants, or the precision of any mean. Nor is it possible to determine from the record whether the model assessment found significant pharmacokinetic changes. The stated purpose and the observed result are different kinds of information, and only the purpose is described.

The design also limits the type of conclusion available. A single-group, open-label study without randomized allocation can describe measurements among the enrolled participants, but it cannot estimate a randomized between-group contrast. The registry record does not report comparative clinical outcomes, and concentration measurements should not be read as direct proof of clinical benefit or harm. No medical recommendation follows from the design description or the safety counts alone.

The reported enrollment of 12 does not show how many participants contributed usable measurements at each time, and the analysis populations are not reported in the registry record. The stated safety counts show 0 participants affected by serious adverse events, 0 affected by other adverse events, and 0 deaths in the reported group; these counts do not establish the absence of risk beyond the observed study record.

The result is therefore a documented study objective and design, not a reported numerical pharmacokinetic finding. Interpretation of concentration magnitude, variability, model fit, and precision requires endpoint results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This study illustrates a statistical distinction between defining a measurement plan and reporting evidence from that plan. The registry record gives a specific continuous endpoint, its units, a mean and standard deviation summary, and planned collection times. Those details help readers understand what the investigators intended to characterize. Without the corresponding observed values and uncertainty measures, however, the central statistical findings cannot be evaluated.

Its single-group structure is also important. Pharmacokinetic observations can be valuable for describing concentrations over time within a population, but a one-group design does not create a randomized contrast. This means the question is principally descriptive and model-based, rather than a comparison of outcomes between treatment arms. Statistical language about treatment effects should reflect that distinction.

The late sampling detail highlights how the pattern of missing measurements can shape interpretation. The registry record says only one participant agreed to the 8-hour sample. A late time point with such limited participation may offer little information about between-participant variability at that time. The record does not state how the analysis addressed this limitation, making transparent reporting of available observations and analytic handling especially relevant.

The study also provides an example of why a planning illustration should not be mistaken for a trial's actual design or observed power. The stated planning assumptions describe a two-arm allocation, while this study is single-group. Planning quantities are conditional on assumptions and an effect size; they do not establish what the study observed or how much power it had after completion. The registry record does not report a design-specific sample-size rationale.

More broadly, the record shows why statistical interpretation depends on complete results as well as design labels. Endpoint estimates, variability, model details, analysis populations, and missing-data methods are necessary to judge precision and robustness. Their absence does not erase the study's documented objective, but it restricts conclusions to the design and reporting information available.

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 principal limitation for statistical interpretation is that the registry record does not report the primary concentration estimates or their standard deviations. It also does not report confidence intervals, model results, or tests addressing the stated pharmacokinetic objective. The intended use of a validated Cefazolin PK Model is mentioned, but its structure, fitting procedure, assumptions, and output are not reported in the registry record.

Sampling completeness is another concern. The planned schedule included 0.5, 1, 2, 4, and 8 hours after the start of infusion, and only one participant agreed to the 8-hour pharmacokinetic blood sample. Counts at other times, reasons for missing samples, and missing-data methods are not reported. A complete concentration profile or the degree of uncertainty at each time cannot be inferred from the schedule alone.

The registry record reports enrollment of 12, but does not report participant characteristics beyond the population description, endpoint-specific sample counts, analysis populations, exclusions, or participant flow. It is therefore unclear how many observations contributed to each summary or whether the analysis population differed from enrollment.

The single-group, open-label design does not provide a concurrent treatment comparison. It can support description of measurements within the enrolled group, but does not isolate a contrast between alternative treatment strategies. The record does not report a study-specific sample-size rationale or a detailed statistical analysis plan. Multiplicity handling, analysis timing, and any interim analyses are not reported in the registry record. These gaps restrict assessment of precision, robustness, and the extent to which analyses followed prespecified methods.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Pharmacokinetics and Safety of Cefazolin 3gm DUPLEX in Adults — NCT05205486.
• Registry record last updated 2025-02-28; status last verified 2025-02.
• Results first posted 2025-02-28.
• 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

The registry record describes a completed Phase 1, open-label, single-group study of a single 3gm cefazolin infusion in adults weighing >= 120 kg who were scheduled for surgery. Enrollment was 12. The primary endpoint was plasma cefazolin concentration in ug/mL, summarized by a mean and standard deviation, with a stated 8-hour timeframe and planned samples at 0.5, 1, 2, 4, and 8 hours after infusion began.

The study summary says concentrations would be assessed using a validated Cefazolin PK Model. Only one participant agreed to the 8-hour pharmacokinetic sample. The registry record does not report the primary concentration results, model outputs, confidence intervals, analysis populations, or detailed missing-data methods. Reported safety counts were 0 participants affected by serious adverse events, 0 affected by other adverse events, and 0 deaths. The single-group design supplies no randomized comparator, and the recorded information supports description of the study objective and reporting limits rather than a comparative treatment conclusion.