This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Pharmacokinetics of Vaniprevir (MK-7009) and Hepatitis C Virus RNA Levels After Vaniprevir Treatment (MK-7009-029) (NCT00954993), a na phase 1 study. The primary outcome is Area Under the Curve (AUC) (0-12 Hrs) of Vaniprevir in the Liver.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00954993 |
| Phase | Phase 1 |
| Condition | Chronic Hepatitis C Infection |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 3 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned participants with chronic hepatitis C infection. Its brief summary specifies genotype 1, HCV-infected participants. The registry record lists enrollment of 3, but the results do not provide a separate description of the participants’ baseline characteristics or explain how many contributed data to each measure.
Intervention
The intervention was vaniprevir, also identified as MK-7009. The arm description states that participants in period 1 took 600 mg twice daily on Days 1-3 and a single 600 mg dose on Day 4. The period was followed by a washout interval of a minimum 30 days and up to approximately 140 days. The remaining dosing details for period 2 are not reported in the registry record.
Comparator
This was a single-group study, not a randomized comparison. The record lists 600 mg and 300 mg dose groups, but the registry’s own design information cautions that the arms are not a like-for-like control comparison. The record does not establish a randomized or masked contrast between those doses.
Primary question
The primary endpoint was the area under the curve (AUC) from 0 to 12 hours for vaniprevir in the liver. Liver biopsies were intended at 6, 12 and 24 hours after the Day 4 dose in each period. The registry states that only a single liver-sample timepoint at either 6 or 12 hours was obtained from each participant, and no participant had a 24-hour sample. The AUC was therefore not calculated.
3. Trial Design
This was a phase 1 study of vaniprevir (MK-7009) in participants with chronic hepatitis C infection. The stated purpose was to evaluate hepatic and plasma pharmacokinetics and hepatitis C virus RNA in genotype 1 infection. The registry lists a single-group model, allocation as not applicable, and no masking. It also lists two dose groups, but explicitly cautions that they do not form a like-for-like control comparison. The record does not describe randomized assignment to dose groups.
For period 1, the described regimen was 600 mg twice daily on Days 1-3, followed by a single 600 mg dose on Day 4. The record describes a subsequent washout interval of a minimum 30 days and up to approximately 140 days. It begins to describe a 300 mg twice-daily regimen in period 2, but the remaining schedule is not reported in the registry record. It would therefore be inappropriate to fill in the full dosing sequence or infer how each participant moved between periods from this description alone.
The study started on 2010-01-13, had a primary completion date of 2011-03-04, and is listed as terminated. Enrollment is recorded as 3. The registry does not state the reason for termination in the information available for this analysis. A termination status and a small enrollment describe the scope of the evidence, but do not by themselves establish why the study ended or what would have happened under a different design.
The intended primary assessment involved liver biopsies after dosing, with samples planned at 6, 12 and 24 hours postdose on Day 4 of each period, up to Day 148. The record says sampling was incomplete and the primary AUC was not calculated. No inferential analyses are listed. Consequently, the available record is primarily informative about the intended design and the limitations of the collected primary-endpoint data, rather than a quantified dose 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.
Period 1
| Stage | Vaniprevir 600 mg - 300 mg Arm |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
Washout
| Stage | Vaniprevir 600 mg - 300 mg Arm |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
Period 2
| Stage | Vaniprevir 600 mg - 300 mg Arm |
|---|---|
| STARTED | 3 |
| COMPLETED | 3 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Since only a single liver sample timepoint at either 6 or 12 hours was obtained from each participant, and no 24 hour timepoint was collected from any participant due to the early termination of the study, the AUC (0-12 hrs) was not calculated
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.
| Characteristic | Unit | Vaniprevir 600 mg - 300 mg Arm |
|---|---|---|
| Participants analysed | 3 | |
| Age, Continuous | Years | 53 (SD 8.89) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 3 |
6. Primary Endpoint
The registry lists the primary outcome as Area Under the Curve (AUC) (0-12 Hrs) of Vaniprevir in the Liver, measured over 6, 12 and 24 hours postdose on day 4 of each period (up to Day 148).
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was vaniprevir AUC from 0 to 12 hours in the liver. AUC is a pharmacokinetic measure that represents exposure over time: conceptually, it combines concentration measurements across the specified interval rather than describing concentration at only one instant. For a drug studied in liver tissue, a liver AUC can be relevant to characterizing drug exposure at the sampled site. General explanation: AUC is useful because two concentration-time profiles can differ in their timing and shape even when a single concentration measurement looks similar.
The registry description says liver biopsies were to be collected at 6, 12 and 24 hours after the Day 4 dose, following twice-daily treatment on Days 1, 2 and 3. It also describes the AUC as the integrated area under the curve for plasma concentration of vaniprevir over time, despite naming the primary endpoint as AUC in the liver. This difference in wording leaves the precise tissue-versus-plasma interpretation unclear in the registry record; it should not be resolved by assuming that one description overrides the other.
Most importantly, the endpoint was not calculated. The record states that each participant had only a single liver-sample timepoint at either 6 or 12 hours, and no participant had a 24-hour timepoint because of early study termination. Thus, the record does not report a primary-endpoint estimate, its variability, or a confidence interval. A planned measurement is not an observed AUC result, and the available sampling description does not support treating the intended endpoint as if it had been quantified.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary result is a limitation of ascertainment, not a numerical estimate of liver exposure. The registry explicitly states that AUC from 0 to 12 hours was not calculated. It explains why: only one liver-sample timepoint, either 6 or 12 hours, was obtained from each participant, and no participant had the planned 24-hour sample because the study terminated early. Since the endpoint requires an exposure profile over an interval, those incomplete samples did not yield the registered AUC outcome.
Accordingly, there is no primary AUC value in this record to interpret as a measure of vaniprevir exposure in liver tissue. There is also no reported estimate of uncertainty around that endpoint. The registry lists 3 participants enrolled, but this enrollment figure does not supply a usable primary-endpoint estimate or establish which participants contributed samples at each timepoint. The record does not report participant-level concentrations, a concentration-time curve, or a summary of the samples that were collected.
The two dose labels should not be read as a controlled efficacy or pharmacokinetic contrast. The design is recorded as single-group, allocation is not applicable, and the registry cautions that the arms are not a like-for-like control comparison. Without a documented randomized comparison and a calculated outcome, differences between the dose-group safety counts cannot establish a dose effect. Nor does the study’s stated interest in HCV RNA mean that a quantified RNA result is available: such results are not reported in the registry record.
Safety data are listed separately for the 600 mg and 300 mg dose groups. The record reports no serious adverse events among the 3 participants at risk in either group. It lists other adverse events for 3 of 3 at risk in the 600 mg group and 2 of 3 at risk in the 300 mg group. These are registry counts, not evidence that the groups were independent or comparable; the record does not establish that they represent separate sets of participants. It also does not provide the event terms in the listed serious-event category, and death counts are recorded as unavailable rather than as zero.
No analyses are listed in the record. It reports no treatment-effect estimate, test statistic, confidence interval or p-value for the primary endpoint. Without these, statistical precision and evidence for a difference cannot be assessed from the primary outcome. The termination and missing endpoint also mean that the results cannot be interpreted as a completed evaluation of the planned liver AUC question. This does not show that vaniprevir did or did not produce a particular exposure or clinical effect; it shows that the registered primary measure is unavailable in the record.
9. Statistical Methods Explained
What does AUC describe?
General explanation: a concentration-time profile tracks measured drug concentration over time. The area under that profile over a specified interval is a summary of exposure during that interval. It reflects both the concentration levels and how long they are present; it is not interchangeable with a single concentration measured at one time. In this study, the registered interval was 0 to 12 hours, and the named tissue was the liver.
To estimate an AUC, investigators need concentration information that supports a profile across the interval. The record describes intended liver sampling at 6, 12 and 24 hours after the Day 4 dose, but reports only one liver-sample timepoint at either 6 or 12 hours for each participant and no 24-hour sample for any participant. It states directly that the AUC was not calculated. Therefore, there is no reported primary AUC summary to interpret, and readers should not reconstruct one from the sampling schedule. The registry description also refers to integrated plasma concentration while naming a liver AUC. That wording ambiguity is not resolved by the record.
What would uncertainty measures tell a reader?
General explanation: a confidence interval describes the range of estimates reasonably compatible with the observed data under a stated statistical procedure. Its width reflects precision as well as the scale and variability of the measurement. A narrow interval generally indicates greater precision than a wide interval, while an interval that is unavailable provides no such information. Because the primary AUC was not calculated and no analyses are listed, the registry provides no confidence interval for that endpoint. There is also no reported standard deviation, standard error, or other measure of the endpoint’s variability.
A p-value, when reported for a specified analysis, summarizes how compatible the data are with a defined null model under that analysis. It does not measure the size or clinical importance of an effect. No primary-endpoint p-value or inferential analysis is reported in this record. A statistical test cannot substitute for the missing endpoint estimate, and the absence of a reported test is not evidence for either a difference or no difference.
Can the dose groups be compared directly?
The record describes a single-group study and says allocation was not applicable. It lists groups named for 600 mg and 300 mg dosing, but warns that the arms are not a like-for-like control comparison. A direct dose comparison would require a clearly defined contrast and a design and analysis that support interpreting the groups as comparable. The record does not report randomized assignment, masking, or an adjusted analysis for such a contrast. It would therefore be misleading to read the listed groups as if they were randomized treatment and control arms.
The described period 1 regimen was 600 mg twice daily on Days 1-3, then a single 600 mg dose on Day 4, followed by a washout interval described as a minimum 30 days and up to approximately 140 days. The period 2 description starts to specify 300 mg twice daily but is incomplete in the registry record. The available information does not establish a complete sequence or justify additional assumptions about the crossover structure. The safety counts likewise do not establish that the dose groups comprise separate participants.
How should planning calculations be read?
General explanation: a sample-size calculation is a planning exercise under assumptions about the effect to detect, variability, significance level, allocation and analysis method. It is not a result observed in a trial. The registry’s stated planning framework uses a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect expressed as a fraction of the observed effect. It also distinguishes participant-per-arm calculations from total-event calculations for time-to-event settings. Those assumptions do not provide an observed treatment effect or validate the missing primary endpoint. The record does not report that this planning illustration was the original study’s design justification. Any planning values should be interpreted as hypothetical illustrations, not as observed power or as evidence that the study could answer its primary question.
General explanation: over-dispersion occurs when count data vary more than an assumed statistical model allows. If present, it can make model-based uncertainty too optimistic unless the analysis accounts for the extra variation. The registry does not report a count-model analysis or whether over-dispersion was assessed, so this concept should not be mistaken for a method applied in this study. More broadly, the record does not report the statistical procedures, covariate adjustments, hypothesis tests, or uncertainty calculations used for the outcomes.
What does the reported analysis status establish?
The registry lists 3 outcome measures and 0 analyses. That means this record does not present a reported analysis for the primary endpoint; it does not reveal whether any unlisted exploratory work occurred outside the registry record. The appropriate interpretation is limited to what is registered: the endpoint was not calculated, and no inferential result is available for it. Without participant-level data or reported summary statistics, readers cannot independently estimate the AUC, its uncertainty, or a dose contrast.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 3 outcome measures and 0 analyses. It identifies the liver AUC as the primary outcome, but does not report results for the other outcome measures in the information. A multiplicity strategy—such as how several outcomes or repeated comparisons would be handled—is not reported in the registry record. It would be inappropriate to infer a prespecified hierarchy, adjustment procedure, or testing plan.
General explanation: when several outcomes or statistical tests are examined, the chance of obtaining an apparently unusual result can increase if each is interpreted in isolation. A prespecified multiplicity approach can define which comparisons are confirmatory and how uncertainty is controlled. That general concern does not establish that a particular adjustment was necessary or used in this study; the record does not report the analysis plan needed to answer that question.
For the primary measure, the stated sampling gaps prevented calculation of the AUC: each participant contributed only a liver sample at either 6 or 12 hours, and no 24-hour sample was collected. The record attributes the lack of the 24-hour sample to early termination. It does not report an imputation procedure, a missing-data model, sensitivity analyses, or reasons for the absent timepoints beyond that statement. Because the endpoint itself was not calculated, the missing samples should not be described as having been filled in or accounted for by a reported analysis.
The analysis populations are not described in the registry record. No population definitions or participant flow are reported for the primary endpoint, the other outcomes, or safety analyses. The enrollment figure and safety denominators do not establish how many participants contributed to each endpoint, and the dose-group counts should not be treated as independent participant groups without supporting information. This limits interpretation of both completeness and comparability.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| 600 mg Dose of Vaniprevir | 0 | 3 | 0.0% |
| 300 mg Dose of Vaniprevir | 0 | 3 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| 600 mg Dose of Vaniprevir | 3 of 3 |
| 300 mg Dose of Vaniprevir | 2 of 3 |
Most frequent non-serious adverse event terms
| Event term | Organ system | 600 mg Dose of Vaniprevir | 300 mg Dose of Vaniprevir |
|---|---|---|---|
| Procedural Pain | Injury, poisoning and procedural complications | 1 of 3 | 1 of 3 |
| Dry Mouth | Gastrointestinal disorders | 1 of 3 | 0 of 3 |
| Nausea | Gastrointestinal disorders | 0 of 3 | 1 of 3 |
| Nasopharyngitis | Infections and infestations | 1 of 3 | 0 of 3 |
| Musculoskeletal Pain | Musculoskeletal and connective tissue disorders | 0 of 3 | 1 of 3 |
| Anger | Psychiatric disorders | 1 of 3 | 0 of 3 |
The registry lists safety counts for a 600 mg dose group and a 300 mg dose group. In each group, 3 participants are recorded as at risk for serious adverse events, with 0 affected. For other adverse events, the record lists 3 of 3 at risk in the 600 mg group and 2 of 3 at risk in the 300 mg group. These counts describe what the registry reports; they do not establish that the groups are independent or directly comparable.
The record does not list serious adverse-event terms. A count of 0 affected for the serious-event category means that no serious adverse event is recorded in that group in this registry entry; it does not prove that a risk is absent. The record also lists deaths as unavailable, not as zero, so the death field cannot be interpreted as evidence that no deaths occurred.
Other adverse events are a separate category from serious adverse events. The counts do not specify event type, timing, severity, duration, or whether a participant experienced more than one event. The record does not provide those details here, and it does not report a statistical comparison of safety between dose groups. With the single-group design and the registry’s warning that the groups are not like-for-like controls, these counts should be read descriptively, not as a causal estimate of differences between doses.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this phase 1 study intended to examine vaniprevir pharmacokinetics and HCV RNA in genotype 1, HCV-infected participants, and that its primary endpoint concerned liver AUC from 0 to 12 hours. It also establishes that the primary endpoint was not calculated. The stated reason is incomplete liver sampling: only a sample at either 6 or 12 hours was obtained from each participant, and no participant had the planned 24-hour sample after early termination.
That distinction matters. The study’s intended question is not the same as a reported result. A planned endpoint, a scheduled sampling time, or the presence of dose-group labels does not supply a quantified exposure estimate. The record does not report a liver AUC value, an uncertainty interval, or a statistical test for the primary measure. It therefore cannot be used to describe the magnitude or precision of the planned liver-exposure outcome.
The available safety data are counts, not a controlled comparison. The record lists no serious adverse events among those recorded at risk, and reports other adverse events in the dose groups. It does not establish that the groups were comparable or that their participants were separate. The safety figures also lack event descriptions in the information, and death counts are unavailable. Those limitations preclude strong interpretation of apparent differences in the descriptive counts.
The record does not report results for HCV RNA, despite the study’s stated interest in RNA levels. It also does not report a reason for termination or a complete analysis plan. The absence of those details should not be converted into assumptions about the study’s conduct, the participants’ outcomes, or the drug’s effects.
In statistical terms, this record describes a planned pharmacokinetic assessment that did not yield its named primary summary, alongside limited descriptive safety counts. It does not establish that vaniprevir produced or failed to produce a particular liver exposure, nor does it provide an estimate of clinical benefit or harm. The defensible conclusion is about what can be interpreted: the primary result is unavailable, the dose groups are not a like-for-like comparison, and the reported safety information is descriptive and incomplete.
13. Why This Trial Matters Statistically
This study is statistically instructive because it separates a protocol’s measurement goal from the result that can actually be analyzed. The primary endpoint was an AUC, which depends on characterizing exposure over an interval. The registry reports that the planned liver sampling was incomplete and that the AUC was not calculated. A well-defined endpoint is not enough to produce an estimate when the observations needed to construct it are absent.
The record also illustrates why design labels matter. Two dose groups do not automatically create a randomized comparison. Here, the model is single-group, allocation is not applicable, masking is none, and the registry explicitly warns against treating the arms as like-for-like controls. Interpreting counts or outcomes as a direct dose effect would go beyond the stated design information.
Another statistical lesson concerns reporting and uncertainty. Enrollment is recorded as 3, but no primary AUC estimate or analysis is reported. Without an estimate and an uncertainty measure, readers cannot assess precision or distinguish a stable pattern from one that could vary substantially with additional observations. A planning calculation, even when based on explicit assumptions, is not a substitute for observed data and is not observed power.
Finally, incomplete records require careful language. No serious adverse events are listed in the relevant registry counts, while death values are unavailable and event descriptions are absent. Treating unavailable information as zero, or treating descriptive counts as a comparative safety analysis, would change what the record says. The central statistical contribution is therefore a clear example of how endpoint availability, study design, and reporting boundaries constrain 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 primary limitation is that the registered liver AUC from 0 to 12 hours was not calculated. The record says each participant had only one liver-sample timepoint at either 6 or 12 hours and that no 24-hour sample was collected because of early termination. It does not report a substitute endpoint estimate or a method for handling the incomplete sampling.
The study is listed as terminated, and enrollment is recorded as 3. The registry information does not state why the study terminated or give enough detail to assess the consequences of termination beyond the missing planned sample timepoint. It also does not report participant-level concentration data, a complete concentration-time profile, or an analysis population for the primary measure.
The design information limits dose interpretation. The study is classified as single-group, allocation is not applicable, and the registry cautions that the dose groups are not like-for-like controls. The available period 2 dosing description is incomplete, so the full regimen and sequence cannot be reconstructed from the registry record. The safety denominators should not be used to infer that the dose groups contain separate participants.
The endpoint wording itself is not fully consistent: the primary title names AUC in the liver, while its description refers to integrated plasma concentration. The record does not clarify whether this is a wording issue or reflects different measurements. Results for HCV RNA are not reported, despite the study’s stated objective, and the reason for termination is not reported in the information.
Finally, the record lists no analyses and provides no reported inferential results for the primary endpoint. The statistical plan, missing-data methods, multiplicity strategy, and analysis-population definitions are not reported in the registry record. These gaps prevent assessment of endpoint precision, adjusted comparisons, or robustness.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Pharmacokinetics of Vaniprevir (MK-7009) and Hepatitis C Virus RNA Levels After Vaniprevir Treatment (MK-7009-029) — NCT00954993.
- Registry record last updated 2018-10-18; status last verified 2018-09.
- Results first posted 2014-09-29.
- 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.
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18. Record Summary
NCT00954993 is a phase 1, single-group study of vaniprevir (MK-7009) in chronic hepatitis C infection. Its stated objective was to evaluate hepatic and plasma pharmacokinetics and HCV RNA in genotype 1 infection. Enrollment is recorded as 3. The study started on 2010-01-13, had a primary completion date of 2011-03-04, and is listed as terminated.
The primary endpoint was vaniprevir AUC from 0 to 12 hours in the liver. The registry states that the AUC was not calculated because each participant had only one liver sample at either 6 or 12 hours and no participant had a 24-hour sample. It lists 3 outcome measures and 0 analyses. HCV RNA results and a reason for termination are not reported in the registry record.
Safety counts are reported by dose group, but the record cautions that the groups are not a like-for-like control comparison. Serious-event counts are zero in both groups; other adverse-event counts are reported, while death values are unavailable. The record supports a description of the intended study and the limitations of its reported results, not a quantified primary-endpoint or dose-comparison conclusion.