Pharmacokinetics of Omadacycline in Cystic Fibrosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Pharmacokinetics of Omadacycline in Cystic Fibrosis (NCT04460586), a na phase 4 study. The primary outcome is Cmax.

2. Clinical Question

The clinical question is primarily pharmacokinetic: what maximum concentrations are observed after the specified omadacycline administrations in patients with cystic fibrosis? It is not framed as a test of clinical benefit against a control treatment. The record gives no numerical endpoint estimate, variability measure, confidence interval, or inferential test result. It therefore does not permit a quantitative answer about the concentrations observed or how certain those estimates are.

The description says intravenous administration is followed by oral administration, but does not report details such as the timing between administrations, the sampling schedule, or whether the same participants contributed measurements to both route-specific assessments. Those design details are not reported in the registry record. Accordingly, the primary question can be described, but the reported information is insufficient to reconstruct the measurement sequence or assess a within-person route comparison.

3. Trial Design

The registry identifies NCT04460586 as a completed phase 4 study titled “Pharmacokinetics of Omadacycline in Cystic Fibrosis.” Its stated purpose is to characterize the pharmacokinetics of intravenous and oral omadacycline in patients with cystic fibrosis. Enrollment is listed as 9. The study has a single-group model, allocation listed as NA, and masking listed as none.

The described regimen is Omadacycline IV followed by PO. The arm description specifies Omadacycline 100mg IV and an Omadacycline 300 mg tablet. The registry lists these as two intervention entries, an injection and an oral tablet. This describes the planned route sequence, but does not establish that the routes were assigned to distinct participant groups or explain the order and timing of measurements. Further details of dosing and sampling are not reported in the registry record.

The registry lists a primary Cmax measure with a timeframe of 3 Days and identifies the mean and standard deviation as the measure and dispersion. It also lists 4 outcome measures and 0 analyses. The actual numerical outcome values and analysis results are not reported in the registry record. The completion status is recorded as completed; the dates listed are 2021-07-01 for study start and 2023-12-01 for primary completion.

This is not a randomized comparison according to the registry record. Its allocation is NA, and the record describes a single group rather than a like-for-like control comparison. The two route labels should therefore not be interpreted automatically as independent randomized arms. Details on any crossover structure, washout, sequencing, or control condition are not reported in the registry record. Sample-size calculations based on an observed effect are planning illustrations, not evidence that this study was designed or powered for a particular comparison.

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.

OMC 100 mg IV + PK (72 h)

Washout (7 days)

OMC 300 mg PO + PK (72 h)

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 Cmax, measured over 3 Days.

Cmax is the maximum concentration of a drug measured after administration. In this study, the primary outcome is identified as Cmax for omadacycline, measured in mg/L, with a stated timeframe of 3 Days. The endpoint description says the aim is to assess the maximum concentration after single-dose oral and intravenous administration. The registry identifies the mean as the summary measure and the standard deviation as the measure of dispersion.

As a general pharmacokinetic concept, peak concentration can describe the highest measured drug concentration over a sampling period. It is useful for characterizing exposure because it focuses on the peak rather than the full concentration-time profile. Interpretation depends on the administration route, the timing and frequency of blood sampling, and how the peak is defined from those measurements. Those detailed procedures are not reported in the registry record.

A mean Cmax would describe the average peak concentration in the analyzed participants, while a standard deviation would describe the spread of participant-level values around that mean. The standard deviation is not a confidence interval: it describes observed variability, whereas a confidence interval describes uncertainty in an estimate. Neither the mean nor the standard deviation values are reported in the registry record, and no confidence interval is listed. The endpoint definition is therefore available, but its observed level and precision cannot be evaluated from the posted results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the endpoint summary describe?

The primary endpoint is Cmax, a continuous measure expressed in mg/L. The record specifies the mean as the summary statistic and standard deviation as the dispersion statistic. General explanation: the mean gives the arithmetic average of measured values, while the standard deviation describes how dispersed individual values are around that average. A standard deviation does not, by itself, show how precisely the mean has been estimated. A confidence interval is a different summary: it expresses uncertainty around an estimate under the assumptions of the analysis.

The Cmax timeframe is 3 Days. The endpoint description refers to the maximum concentration after single-dose oral and intravenous administration. The registry record does not include the numerical mean or standard deviation, nor does it report a confidence interval or a test result. As a result, readers cannot assess the observed concentration level, variability, or precision from the posted results.

How should the route description be read?

The intervention description is Omadacycline IV followed by PO, with Omadacycline 100mg IV and an Omadacycline 300 mg tablet. The study is identified as single group, with allocation listed as NA and masking as none. These details indicate that the registry does not describe a randomized allocation to separate route groups. They do not, by themselves, explain whether observations for both routes came from the same participants or how measurements were ordered and timed.

General explanation: when repeated measurements come from the same participant, those observations may be statistically related. An analysis can account for that relationship, while an analysis treating them as independent may not. The registry does not report whether the Cmax observations were paired, the model used, or how any within-participant correlation was handled. It is therefore not possible to infer the analysis structure from the regimen wording alone.

What can standard deviation and confidence intervals tell readers?

General explanation: standard deviation describes variation among observations in the analyzed sample. A confidence interval describes uncertainty in an estimated quantity, such as a mean or a difference, and depends on the data and analysis assumptions. A narrow interval would indicate greater precision than a wider interval, but neither is reported for the primary endpoint. No interval can be reconstructed without the relevant numerical results and analysis details.

For continuous data, interpretation also depends on the measurement process, sample size, distribution of values, and whether the analysis uses an appropriate model. A small number of observations can make estimates sensitive to individual values; this is a general statistical consideration, not a claim about the unreported Cmax distribution in this study. Enrollment is listed as 9, but the number included in the primary analysis is not reported in the registry record.

What does the planning illustration represent?

The sample-size material is described as a planning illustration calculated from an observed effect, rather than as the trial’s own design justification. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. For outcomes other than time-to-event outcomes, the illustration is expressed as participants per arm. These are hypothetical planning assumptions; they do not establish that the study used those assumptions to set enrollment or conduct its analysis.

General explanation: a sample-size calculation estimates how many observations might be needed to detect a chosen effect under specified assumptions about variability, significance level, and power. Such a calculation depends on the effect size selected and the analysis model. A planning illustration based on an observed effect is not observed power and does not show that a completed study had adequate precision. The actual effect values and numerical planning results are not included in the registry record, so no calculation can be independently assessed from the posted information.

The illustration assumes equal allocation between two arms, but the study itself is registered as single group and is not a randomized comparison. Consequently, the illustration’s two-arm framework should not be read as a description of the actual design. It is a conditional planning scenario, not evidence that two independent control and treatment groups were enrolled.

What inferential results are available?

The registry lists 4 outcome measures and 0 analyses. It does not report a statistical test, model, adjusted estimate, unadjusted estimate, confidence interval, or p-value for Cmax. Without these quantities, statistical significance and precision cannot be evaluated. Even if a numerical difference were available, a p-value alone would not describe its magnitude or clinical relevance; estimates and uncertainty would also be needed. No estimate or p-value is reported in the registry record.

General explanation: statistical inference uses a model and assumptions to relate observed data to uncertainty about a target quantity. For a continuous endpoint, an analysis might estimate a mean or a contrast, but the correct approach depends on how observations were collected and the intended question. Since the registry does not report the analysis method or the numerical results, readers cannot check model assumptions, reproduce an estimate, or judge whether the analysis accounted for the study’s structure.

The lack of reported analyses is not evidence that no analysis was performed outside the registry. It means the registry record does not document an analysis result that can be interpreted. The appropriate reading is limited to the registered aims and the information actually reported, without treating missing statistical details as evidence for or against a pharmacokinetic effect.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures, but does not report numerical analyses for them; it lists 0 analyses. The Cmax measure is identified as primary, but details of any prespecified statistical testing strategy are not reported in the registry record. In particular, the record does not describe whether or how the study accounted for multiple outcomes or multiple comparisons.

General explanation: multiplicity arises when several hypotheses or outcomes are examined. Testing many outcomes can increase the chance of at least one apparently notable result, so a prespecified strategy may be used to control error rates or prioritize outcomes. The registry’s count of outcome measures alone does not establish that multiple statistical tests were conducted, and no multiplicity adjustment should be presumed.

Missing-data handling is also not reported in the registry record. The record lists enrollment of 9 but does not state how many participants contributed to each outcome, whether measurements were missing, why any were missing, or how missing values were treated. It does not describe imputation, exclusions, or sensitivity analyses. Thus, the number enrolled cannot be assumed to equal the number analyzed for Cmax or the safety outcomes.

The analysis population is not reported in the registry record. There is no description of inclusion criteria for the pharmacokinetic analysis, participant disposition, or whether all enrolled participants were included in each summary. These omissions limit assessment of selection and completeness. A reader cannot determine whether reported values, if available elsewhere, would represent all enrolled participants or a subset based on the measurements obtained.

General explanation: analysis populations and missing-data methods matter because the people and observations included can affect an estimate and its uncertainty. A clear record would ordinarily identify who was analyzed and how incomplete measurements were handled. Since those details are not reported, conclusions about completeness, attrition, or the representativeness of any analysis cannot be drawn from 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry lists serious adverse events for two administration groups. For Omadacycline 100 mg IV, serious adverse events affected 0 of 9 participants at risk. For Omadacycline 300 mg PO, serious adverse events affected 0 of 9 participants at risk. The listed death count is 0 for each group.

The record also lists other adverse events: 2 of 9 participants at risk in the IV group and 1 of 9 in the PO group. These are counts, not estimates of a causal route effect. The record does not provide event terms for these other adverse events or list any top serious adverse event terms. It also does not explain how the groups relate to the single-group, IV-followed-by-PO regimen, including whether the same participants contributed to both group counts.

General explanation: adverse event counts describe events recorded during a study; they do not establish that an intervention caused an event. Zero serious events in the listed records means none are reported in those groups, not that risk is absent. With enrollment listed as 9 and no detailed analysis or follow-up information reported, these counts are descriptive and should not be treated as a comparative safety test.

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

The registry record documents a study intended to characterize intravenous and oral omadacycline pharmacokinetics in patients with cystic fibrosis. It identifies Cmax as the primary endpoint, gives its unit and timeframe, and describes an IV-followed-by-oral regimen. It also records enrollment of 9 and selected adverse event counts. These details clarify the study’s stated purpose and what it intended to measure.

The record does not report the numerical Cmax findings. It therefore cannot show the observed mean maximum concentration, the variation among participants, or the precision of an estimate. It also does not report an inferential comparison between routes. No conclusion about a higher or lower concentration by route, or about the size of any route-related difference, can be drawn from the posted results.

The study is single group, with allocation listed as NA and masking listed as none. It is not a randomized comparison. The regimen description alone does not clarify whether the same participants contributed observations for both routes or how those observations were analyzed. Without those details and the actual outcome estimates, the registry record cannot establish a controlled route contrast.

The safety counts are limited descriptive information. The registry lists 0 serious adverse events in each administration group, 0 deaths in each, and other adverse events in both groups. It does not report event terms for those other events or provide a statistical safety comparison. These counts do not prove that no risk exists and do not demonstrate that one route is safer than another.

More broadly, the record does not report the analysis population, missing-data handling, statistical model, or confidence intervals. These omissions prevent assessment of statistical precision, robustness, or completeness. The study’s stated aim is informative, but the registry record does not supply the quantitative results needed to judge the pharmacokinetic estimates. Claims about clinical effectiveness or treatment choice are outside what these posted data establish.

13. Why This Trial Matters Statistically

Pharmacokinetic studies ask how drug concentrations behave after administration, a question distinct from whether a treatment improves a clinical outcome. Cmax is one way to describe the concentration profile: it focuses on the highest measured concentration. Identifying the endpoint and administration routes helps define the scientific question even when numerical results are unavailable.

This study is statistically notable for its single-group description and sequential IV-followed-by-oral regimen. The route labels might be mistaken for separate comparison arms, but allocation is listed as NA and the record does not describe a randomized control group. Clarifying that distinction is essential: a set of administration-specific measurements does not automatically constitute a randomized or independent-groups comparison.

The registry also illustrates the difference between an endpoint definition and a reported result. It specifies Cmax, the unit mg/L, a timeframe of 3 Days, and the mean with standard deviation, yet the numerical summaries and analyses are not reported in the registry record. Without estimates and uncertainty, the statistical evidence cannot be evaluated, even though the intended measurement is clear.

The listed sample-size assumptions serve as a planning illustration rather than an account of the study’s design. The assumptions include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Because the registered study is single group and nonrandomized, the illustration should not be interpreted as proof of the actual design or as observed power.

Finally, the record’s limited safety counts underscore why denominators, event definitions, participant overlap, and analysis methods matter. The counts are useful descriptive details, but they do not establish causal differences or replace a complete analysis. For readers assessing clinical research, distinguishing documented results from intended questions is a central part of sound statistical interpretation.

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 interpretation is that numerical pharmacokinetic results are not reported in the registry record. Although Cmax is defined as the primary endpoint and the record specifies mean and standard deviation, neither summary value is included. There are also no confidence intervals, test results, or reported analyses. The magnitude and precision of the primary endpoint therefore remain unknown from the posted results.

The registry describes a single-group study, allocation as NA, no masking, and an IV-followed-by-oral regimen. It does not describe a randomized control condition. The relationship between the two route-specific safety group labels and the single-group design is not explained, and the record does not state whether the same participants contributed to each route’s pharmacokinetic measurements. The sequence and timing of doses and measurements are not reported.

Enrollment is listed as 9, but the analysis population and participant flow are not reported. The number with complete Cmax data, the number contributing data for each route, and the handling of missing measurements are not specified. Consequently, enrollment cannot be assumed to represent the denominator for the primary endpoint.

The registry lists 4 outcome measures and 0 analyses, but does not describe multiplicity handling, a statistical model, or prespecified analysis procedures. The planning assumptions are described as an illustration based on an observed effect, not as the trial’s own design justification. These limitations prevent an independent assessment of the study’s statistical precision, analysis choices, and completeness.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Pharmacokinetics of Omadacycline in Cystic Fibrosis — NCT04460586.
• Registry record last updated 2026-05-08; status last verified 2026-05.
• Results first posted 2026-05-08.
• 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

NCT04460586 is a completed phase 4 study of omadacycline pharmacokinetics in patients with cystic fibrosis. The registry lists enrollment of 9 and describes a single-group regimen of Omadacycline 100mg IV followed by an Omadacycline 300 mg tablet. Allocation is listed as NA and masking as none.

The primary endpoint is Cmax in mg/L, summarized as a mean with standard deviation, with a timeframe of 3 Days. The registry lists 4 outcome measures and 0 analyses. Numerical pharmacokinetic results, confidence intervals, statistical tests, analysis populations, and missing-data procedures are not reported in the registry record.

Safety listings show 0 serious adverse events and 0 deaths in each route group; other adverse events are listed for 2 of 9 participants in the IV group and 1 of 9 in the PO group. These counts are descriptive and do not establish a causal comparison between routes.