A Drug-Drug Interaction Study to Assess the Pharmacokinetics of DC-806 When Orally Administered Alone, When Coadministered With Itraconazole, and When Coadministered With Carbamazepine in Healthy Adult Participants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Drug-Drug Interaction Study to Assess the Pharmacokinetics of DC-806 When Orally Administered Alone, When Coadministered With Itraconazole, and When Coadministered With Carbamazepine in Healthy Adult Participants (NCT05994807), a non-randomized phase 1 study. The primary outcome is Cohort 1: Maximum Observed Plasma Concentration (Cmax) of DC-806.

2. Clinical Question

The central statistical question is whether the observed plasma concentration profile of DC-806 differs when the drug is taken with a CYP3A4 inhibitor or inducer rather than alone. The study uses within-cohort treatment sequences to examine those pharmacokinetic conditions. It does not provide a randomized parallel comparison of participants assigned to coadministration versus DC-806 alone. The record therefore describes a drug–drug interaction assessment, not a treatment-effect comparison designed to establish clinical benefit.

3. Trial Design

This is a Phase 1, single-center, open-label drug–drug interaction study. The registry describes a parallel model with two cohorts, non-randomized allocation, no masking, and a fixed sequence of study periods. Enrollment was 33, and the record lists the study as completed. The study start date is 2023-08-08 and the primary completion date is 2023-09-20.

Cohort 1 evaluated DC-806 200 mg alone and with itraconazole. The arm description states that participants received a single oral dose of DC-806 under fasted conditions on Day 1, followed by itraconazole on Days 4 to 6. The primary outcome compares DC-806 Cmax on Day 1 with Cmax when coadministered with itraconazole on Day 7. The available arm description is truncated after the Day 7 administration details, so further dosing or conduct details are not reported in the registry record.

Cohort 2 evaluated DC-806 800 mg alone and with carbamazepine. Its arm description states that participants received DC-806 on Day 1 and then multiple ascending doses of carbamazepine beginning on Day 4. The description is truncated before the full schedule is given. The registry’s safety groups identify a period of carbamazepine exposure from Days 4 to 17 and coadministration from Day 18, but the full dosing details are not reported in the registry record.

The sequential design is relevant to interpretation: the pharmacokinetic conditions are encountered in an assigned order rather than through randomized treatment assignment. There is no masked comparison. Cohort 1 and Cohort 2 use different DC-806 doses and different interacting drugs, so a comparison between cohorts would not isolate the effect of either interacting drug. The registry record does not report a sample-size justification, details of sequence-related safeguards, or an analysis plan.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All cohort 1 participants who had received at least 1 dose of DC-806 or itraconazole and had evaluable data for this outcome.

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: All enrolled participants.

6. Primary Endpoint

The registry lists the primary outcome as Cohort 1: Maximum Observed Plasma Concentration (Cmax) of DC-806, measured over Day 1 (Predose, 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 18, 24, 36, 48, 72 hours postdose), Day 7 (Predose, 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 18, 24, 36, 48, 72, 96 hours postdose).

The listed primary endpoint is Cohort 1 maximum observed plasma concentration, or Cmax, of DC-806. It is reported as a geometric mean with geometric coefficient of variation, in nanograms per milliliter. Measurements were scheduled on Day 1 after DC-806 alone and on Day 7 when DC-806 was coadministered with itraconazole. The listed sampling schedule includes predose and multiple postdose time points through 72 hours on Day 1 and through 96 hours on Day 7.

Cmax is the highest measured concentration in a pharmacokinetic sampling profile. It is used to describe the peak concentration reached after a dose. Comparing Cmax under the two conditions can help characterize whether coadministration is associated with a change in peak systemic exposure. It is one component of pharmacokinetics; by itself, it does not describe the whole concentration-time profile or establish a clinical effect.

Geometric means are commonly used for pharmacokinetic measures that are analyzed on a multiplicative scale or have a skewed distribution. The geometric coefficient of variation describes relative variability around the geometric mean. As a general statistical point, the geometric summary is not the same as an arithmetic average, so it should be interpreted using its stated scale and accompanying variability measure.

The registry record identifies the endpoint and collection schedule but does not report the observed Cmax values, geometric coefficients of variation, a treatment comparison estimate, or a confidence interval. It also does not list a primary outcome for Cohort 2 in the posted primary-outcome details.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record names Cmax as the primary outcome for Cohort 1 and specifies a geometric mean and geometric coefficient of variation. It does not report an inferential analysis, a comparison estimate, or uncertainty interval. The general concepts below explain how such pharmacokinetic summaries are commonly read; they are not a description of unreported methods from this trial.

What does Cmax capture?

Cmax is the maximum concentration observed in the scheduled blood-sampling profile after a dose. It summarizes the peak, rather than the full exposure over time. The registry describes measurements for DC-806 alone on Day 1 and with itraconazole on Day 7, with samples taken at predose and specified postdose times. Because Cmax depends on the observed profile, its interpretation is linked to the sampling schedule: the measure is the maximum among collected samples, not necessarily a continuously observed peak between them.

Pharmacokinetic assessments commonly consider Cmax alongside other measures that describe overall exposure or how concentrations change over time. The registry identifies seven outcome measures in total, but it does not list their full names or results in the record. It is therefore not possible to say which additional measures were reported or whether they support the same interpretation as Cmax.

Why report a geometric mean?

Concentration measurements often have a multiplicative pattern of variation. A geometric mean is formed on a logarithmic scale and then expressed back on the original scale. In general, this summary can be useful when values are right-skewed or when proportional changes are of interest. It should not be read as an arithmetic average. The registry pairs the geometric mean with a geometric coefficient of variation, a measure of relative variability.

For a treatment comparison analyzed on a logarithmic scale, an estimate may be expressed as a ratio of geometric means. Such a ratio would describe relative concentration under the coadministration condition compared with the alone condition. This is a general explanation only: the registry record does not report a ratio, a confidence interval, or the analysis used to estimate one. No relative change can be derived from the reported material.

What does a confidence interval add?

In general, a confidence interval describes the statistical uncertainty around an estimated quantity under the assumptions of the analysis. Its width reflects the precision of the estimate, and the interval gives a range of values compatible with the data and method at the stated confidence level. A confidence interval is not reported for the primary outcome in the registry record. Without an estimate and interval, the amount of uncertainty around a Cmax comparison cannot be evaluated.

A p-value, if reported, would address compatibility of the data with a specified statistical null hypothesis under the assumptions of a test. It would not by itself quantify the size or clinical importance of a pharmacokinetic difference. The registry record reports no analysis for the primary outcome, so a p-value or testing conclusion is not available.

Why does the sequence matter?

This study used a fixed sequence, with DC-806 administered alone before the interacting drug and coadministration period. In general, within-participant sequence comparisons can reduce the influence of stable differences between people because each participant may contribute measurements under more than one condition. At the same time, fixed order means that treatment condition and study period occur in a particular order. Time-related changes or carryover can complicate interpretation if they are relevant. The registry does not report a period-effect or carryover analysis, nor does it describe a washout plan; these details are not reported in the registry record.

The cohorts are not randomized against one another. Cohort 1 uses DC-806 200 mg with itraconazole, whereas Cohort 2 uses DC-806 800 mg with carbamazepine. The different doses and coadministered drugs mean that cross-cohort differences cannot be attributed solely to the interacting drug. The record characterizes the study as a two-cohort parallel model, while the arm descriptions show sequential study periods within cohorts; the stated design terms do not turn the cohorts into a randomized head-to-head comparison.

How should planning illustrations be read?

Any sample-size figures calculated from an observed effect are planning illustrations, not observed power. In general, such calculations ask how many participants per arm might be needed under specified assumptions to detect a chosen fraction of an effect. The assumptions described for this study’s illustrations include a two-sided significance level of 0.05, equal allocation, and a normal approximation. These are planning assumptions, not evidence that the trial was designed with those assumptions or had a particular probability of detecting an effect. The registry record does not report the trial’s own sample-size justification. Since the primary effect estimate is not reported in the registry record, a planning illustration should not be treated as a substitute for observed results.

Over-dispersion is a general concern when count outcomes vary more than a simple model assumes. In such settings, standard errors can be too small if extra variability is ignored. That concept is not central to the listed continuous pharmacokinetic endpoint, and the registry does not report a count model or an over-dispersion analysis. The safety counts are descriptive entries rather than evidence of a fitted statistical model.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists seven outcome measures, while the posted record reports zero analyses. It does not state how the primary Cmax outcome was analyzed, whether secondary outcomes were tested, or whether any adjustment for multiple comparisons was planned. A multiplicity strategy is therefore not reported in the registry record. In general, when many outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase; an adjustment or a clearly defined testing hierarchy may address that concern. No such approach can be attributed to this study from the available record.

The record does not report how missing pharmacokinetic measurements were handled, whether any values were excluded, or how incomplete sampling affected Cmax. The primary outcome population is described as Cohort 1 participants who received at least one dose of DC-806 or itraconazole and had evaluable data. The number of participants meeting that definition, and the criteria for evaluability, are not reported in the registry record. Enrollment should not be assumed to equal the analysis population.

The analysis populations for Cohort 2 and for the secondary safety outcome are also not detailed beyond the safety denominators displayed in the registry entries. The record does not state whether participants were analyzed according to a prespecified population definition, how protocol deviations were handled, or whether missing safety information occurred. These items are not reported in the registry record.

These gaps limit assessment of how results were selected, how incomplete data may have influenced estimates, and whether the analysis followed a prespecified plan. They do not demonstrate that a particular method was or was not used; they indicate only that the method is not reported in the registry record.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry’s serious adverse event entries show zero affected participants in every listed treatment group, and the death count is zero in every group. The at-risk denominators vary by group: Cohort 1 entries list 17 participants for DC-806 alone and overall, and 16 for itraconazole and DC-806 with itraconazole. Cohort 2 entries list 16 for DC-806 alone, carbamazepine, and overall, and 14 for DC-806 with carbamazepine. These are group-specific denominators, not one common denominator for the whole study.

A zero count means that no serious adverse event or death was recorded in that group in the registry entry. It does not show that the underlying risk is zero. With a limited number of participants, uncommon events may not occur during the observed study period, even if a risk exists. The registry record does not report confidence intervals for these counts or additional follow-up detail that would support a more precise risk estimate.

The groups reflect periods of the fixed-sequence study and should not be treated as randomized safety arms. Some participants may contribute to more than one period; the entries are not necessarily independent samples. The record also lists non-serious adverse event counts separately. Serious adverse event counts should not be conflated with the total number of participants experiencing any adverse event.

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

The registry record identifies a focused Phase 1 pharmacokinetic question: how DC-806 exposure, including peak concentration, is assessed when DC-806 is given alone and when it is coadministered with itraconazole or carbamazepine. The study’s two-cohort structure separates the interacting drugs and DC-806 doses. Its results could inform characterization of drug–drug interactions if numerical pharmacokinetic estimates and their uncertainty were reported.

The posted record does not give the primary Cmax values or a statistical comparison. It therefore does not establish whether Cmax was higher or lower with itraconazole, how large any difference was, or how precise an estimate might be. It also does not report numerical pharmacokinetic findings for the carbamazepine cohort. No conclusion about the magnitude of either interaction can be drawn from the information recorded.

The absence of reported estimates is not evidence that the conditions had identical pharmacokinetics, and it is not evidence of a difference. It is a limitation of what can be interpreted from this registry record. The stated objective and endpoint describe what was investigated; without the corresponding results, they do not answer the quantitative question.

The study is not a randomized clinical-outcome trial. It enrolled healthy adult participants and assessed pharmacokinetics and adverse events. Its design and outcomes do not establish how findings would apply to people with a medical condition, or whether any pharmacokinetic change would produce a clinical consequence. No medical conclusion should be inferred from the design alone.

The serious adverse event entries record zero serious events and zero deaths in the listed groups. These descriptive counts do not demonstrate absence of risk, particularly for uncommon events, and they do not replace a broader safety assessment. The registry also does not report enough statistical detail to assess multiplicity, missing data, or the precision of safety estimates.

13. Why This Trial Matters Statistically

Drug–drug interaction studies are statistically distinctive because they focus on how one drug’s concentration profile may change in the presence of another. A pharmacokinetic measure such as Cmax captures a specific feature of that profile: the observed peak. The registry record makes the intended contrast clear for Cohort 1 by naming DC-806 alone and DC-806 with itraconazole, while the study objective also identifies carbamazepine as a second interacting drug.

The design illustrates why the comparison structure matters. Treatment conditions occur in a fixed sequence within two non-randomized cohorts, and the cohorts use different DC-806 doses and different coadministered drugs. The comparisons cannot be read as if participants had been randomly assigned to interchangeable arms. Recognizing that distinction helps prevent a cross-cohort contrast from being mistaken for an isolated comparison of interacting drugs.

Reporting the estimate and its uncertainty is essential to the statistical interpretation. A named endpoint and sampling schedule do not reveal the observed effect. Without Cmax estimates, variability, and a treatment contrast, readers cannot assess either the direction of the result or its precision. This record therefore demonstrates the difference between documenting a planned measurement and reporting an interpretable result.

The safety entries also illustrate the limits of zero counts. They are informative descriptions of recorded events in the listed groups, but they do not establish that rare harms are absent. Taken together, the design and reporting make this record useful for understanding the study question and its structure, while leaving the central quantitative pharmacokinetic findings unavailable.

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 most consequential limitation for statistical interpretation is that the registry record does not report the primary Cmax results. No geometric means, geometric coefficients of variation, treatment contrast, confidence interval, or p-value are listed. Numerical results for the carbamazepine cohort are also not reported in the primary-outcome details. The magnitude, direction, and precision of the pharmacokinetic findings cannot be evaluated.

The study is open-label, non-randomized, and fixed-sequence. The record does not describe a randomized treatment order or a concurrent control group. Although within-cohort sequential measurements address different treatment conditions, period effects and other order-related influences cannot be assessed from the details reported. The registry does not describe a washout plan or a carryover assessment.

The cohorts differ in both interacting drug and DC-806 dose: Cohort 1 concerns DC-806 200 mg with itraconazole, and Cohort 2 concerns DC-806 800 mg with carbamazepine. As a result, any comparison between cohorts would not isolate the effect of the interacting drug. The primary outcome listing is specific to Cohort 1, limiting the ability to assess whether the stated objective was answered for both cohorts from the posted outcome details.

The primary outcome population requires evaluable data, but the number of participants included in that analysis and the definition of evaluability are not reported in the registry record. Missing-data handling, multiplicity procedures, the statistical analysis plan, and the trial’s sample-size justification are also not reported. The available arm descriptions are truncated, leaving portions of the dosing schedules unclear. These reporting gaps do not establish that analyses or procedures were absent; they mean they cannot be assessed from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Drug-Drug Interaction Study to Assess the Pharmacokinetics of DC-806 When Orally Administered Alone, When Coadministered With Itraconazole, and When Coadministered With Carbamazepine in Healthy Adult Participants — NCT05994807.
• Registry record last updated 2026-10-19; status last verified 2026-07.
• Results first posted 2026-10-19.
• 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

NCT05994807 is a completed Phase 1, single-center, open-label, non-randomized, fixed-sequence drug–drug interaction study in healthy adults. The registry reports enrollment of 33 and a two-cohort design. Cohort 1 assessed DC-806 200 mg alone and with itraconazole; Cohort 2 assessed DC-806 800 mg alone and with carbamazepine.

The listed primary outcome is Cohort 1 Cmax, expressed as a geometric mean with geometric coefficient of variation. The record defines the sampling schedule but does not report the numerical Cmax results or an analysis. Serious adverse events and deaths are recorded as zero in all listed groups. The record does not report the statistical analysis plan, missing-data methods, multiplicity approach, or sample-size justification.