An Exploratory Study of Telaprevir in Treatment-Naive Participants With Chronic Genotype 4 Hepatitis C Virus Infection: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for An Exploratory Study of Telaprevir in Treatment-Naive Participants With Chronic Genotype 4 Hepatitis C Virus Infection (NCT00580801), a randomized phase 2 study. The primary outcome is Change From Baseline in Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) Levels at Day 15.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group Phase IIa trial. The registry’s masking field describes the study as double masked, while the official title calls it partially blinded. Those descriptions do not specify which participants or study personnel were masked, or how masking was implemented; those details are not reported in the registry record. The allocation method and the planned allocation ratio are also not reported.

Enrollment was 24. The registry describes three regimens: telaprevir followed by pegylated-interferon-alfa-2a and ribavirin; telaprevir with both medicines; and matching placebo with both medicines. In the arm descriptions, telaprevir or matching placebo was administered three times daily for 2 weeks. Pegylated-interferon-alfa-2a was described as a weekly subcutaneous injection, and ribavirin as a daily oral tablet. The description of the telaprevir-first regimen is incomplete in the registry record, so its later treatment duration cannot be established from that description.

The primary outcome was assessed at baseline and Day 15. The registry lists 12 outcome measures and 6 analyses, but does not report the specific analysis methods for those analyses. It identifies the primary outcome statistic as the median and its dispersion as the full range. The number evaluated at each time point could differ from the number randomized, because the outcome description defines the analysis population as randomized participants who received at least one dose and says that the evaluated number is specific to each time point and arm.

The study status is completed. Its start is recorded as 2008-01 and primary completion as 2010-01. A detailed schedule of assessments, randomization procedure, treatment adherence information and protocol deviations is not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full analysis included all randomized participants who received at least one dose of the telaprevir or placebo. "n" signifies those participants who were evaluated for this measure at the specified time point for each arm group respectively.

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 Change From Baseline in Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) Levels at Day 15, measured over Baseline and Day 15.

The primary outcome measures change from baseline in hepatitis C virus ribonucleic acid (HCV RNA) levels at Day 15. HCV RNA is a measure of viral material in plasma; the registry says these levels were used to assess antiviral activity. The unit is log 10 IU/mL, and the specified summary is the median with a full range. The registry does not give the actual median changes or ranges by arm.

The outcome description also defines a viral response as either undetectable HCV RNA or an HCV RNA level less than 25 IU/mL. Undetectable means that no HCV target was detected in the plasma sample. The less-than-25 IU/mL definition refers to a concentration below the assay’s limit of quantification, stated as 25 IU/mL. These definitions help interpret the viral-response outcomes, but they do not replace the primary outcome, which is change from baseline in RNA level.

HCV RNA was measured using the COBAS TaqMan HCV test Version 2.0, based on real-time reverse transcription-polymerase chain reaction methodology. Early RNA change is used in general as a biological measure of antiviral activity because it describes how the measured viral level changes over a specified period. It is not, by itself, a complete account of later viral response, sustained response, relapse, safety or patient experience. The registry lists several such secondary outcomes, but their results are not included in the record details described for this analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a change score: it compares an HCV RNA measurement at Day 15 with the participant’s baseline measurement. In general, change scores express movement from an initial value rather than reporting only the later measurement. The endpoint’s unit is log 10 IU/mL, and the registry specifies a median as its summary. The actual values and the exact calculation convention for change are not reported in the registry record.

Why report a median and full range?

In general, a median describes the middle of a set of observations after they are ordered. It is less affected than a mean by unusually high or low observations, which can be useful when measurements are skewed. The full range gives the lowest and highest observed values and conveys the spread across the observations, but it does not show how values are distributed between those extremes. A range is not a confidence interval: it describes observed values, whereas a confidence interval expresses uncertainty about an estimated quantity under a statistical model. The registry names the median and full range but does not provide their values for the primary endpoint.

What does randomization contribute?

In general, random assignment aims to make groups comparable at the start with respect to both measured and unmeasured characteristics. It supports causal comparison when allocation is implemented as planned and outcomes are analyzed appropriately. Randomization does not guarantee that small groups will have identical baseline characteristics, and the registry record does not give the randomization procedure or baseline values needed to assess group balance. It also does not identify the allocation ratio. The record describes three parallel treatment groups, with 8 participants at risk in each group for the reported adverse-event summaries.

What can be inferred from a confidence interval or p-value?

In general, a confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. Its width communicates precision: wider intervals indicate less precise estimation. A p-value, when calculated under a stated model, describes how incompatible the observed data are with a specified null hypothesis; it is not the probability that a treatment is effective or ineffective. Neither a confidence interval nor a p-value for the primary outcome is reported in the registry record. No inferential conclusion about the Day 15 contrast can be reconstructed without the outcome estimates and the relevant analysis details.

What do the planning assumptions mean?

The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation. The illustrations consider detecting a stated fraction of the observed effect. In general, a sample-size illustration translates assumptions about an effect, variability, significance threshold and desired power into a planning requirement. It is not a description of the number actually analyzed, and it is not observed power. For time-to-event outcomes, the stated planning approach uses the total number of events and the Schoenfeld method; for other outcomes, it expresses the result as participants per arm. These are planning conventions, not evidence that the trial used a particular design justification. The trial’s own sample-size justification is not reported in the registry record.

The planning description refers to two-arm comparisons, while the study has three treatment groups and the primary outcome has not been reduced to one comparison. The actual pairwise comparison, effect used for each illustration, and any group-specific planning decisions are not reported in the registry record. It would therefore be inappropriate to treat a planning illustration as a direct account of the trial’s original enrollment target or statistical rationale.

How should multiple outcomes be considered?

The registry lists 12 outcome measures and 6 analyses. In general, evaluating multiple outcomes or treatment contrasts creates multiple opportunities for a seemingly notable result to arise by chance. Multiplicity procedures can control or otherwise address that issue, but the choice depends on the questions and analysis plan. The registry record does not report whether an adjustment was planned or applied, how the 6 analyses map to the listed outcomes, or which comparisons were designated primary beyond naming the Day 15 HCV RNA change as the primary outcome. Those details cannot be inferred from the count of outcomes and analyses.

The primary outcome description defines a full analysis population as all randomized participants who received at least one dose of telaprevir or placebo. In general, requiring at least one dose is different from analyzing every randomized participant, because a randomized participant who never received a dose would not meet that definition. The record does not state whether any randomized participant failed to receive a dose, how missing Day 15 measurements were handled, or whether other analysis populations were used. Those omissions limit assessment of potential bias due to missing outcomes or exclusions.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 12 outcome measures and 6 analyses. The named secondary outcomes cover viral response, time to first response, viral breakthrough, sustained viral response, relapse and measures of telaprevir concentration. Looking at several outcomes or contrasts can increase the chance of an apparently notable finding arising by chance. In general, a prespecified testing strategy or multiplicity adjustment can address that issue, but no such strategy is reported in the registry record. The relationship between the 6 analyses and the 12 listed outcomes, and the specific statistical tests used, are not reported.

The Day 15 HCV RNA change is identified as the primary outcome. The record does not report whether it was tested against a specified null value, whether comparisons among all three arms were planned, or which pairwise contrasts were intended. It also gives no primary-outcome estimates, confidence intervals or p-values in the record details described for this analysis. Therefore, neither the multiplicity approach nor the inferential results can be evaluated from the listed outcome names alone.

For the primary endpoint, the analysis population is defined as randomized participants who received at least one dose of telaprevir or placebo. The registry says that the number evaluated signifies participants assessed at the specified time point in each arm. It does not report the number missing at Day 15, reasons for missing measurements, imputation methods, handling of withdrawals, or sensitivity analyses. The numbers randomized, dosed and evaluated for the primary outcome by arm are not all reported in the available record details. These gaps prevent assessment of how missing observations or post-randomization exclusions may have affected the comparison.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cholelithiasis (12.5%).

The serious adverse event summaries list 8 participants at risk in each of the three groups. Serious adverse events affected 1 participant in the telaprevir-then-pegylated-interferon-alfa-2a and ribavirin group, and 0 participants in the telaprevir combination group and placebo combination group. These are counts for the groups, not estimates that establish a comparative safety difference. With only 8 participants at risk in each group, the counts are limited observations and do not provide a precise picture of uncommon events.

Other adverse events affected 8 participants in each group. The registry lists cholelithiasis at 12.5% among the top serious adverse event terms, but the information available does not identify its arm or give additional event details. The death field is null for each group; death counts are therefore not reported in the registry record. A missing count should not be interpreted as confirmation that no deaths occurred. The record does not provide event onset, duration, severity beyond the serious-event classification, relatedness assessments or participant-level details needed for further interpretation.

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

The trial addresses whether telaprevir, alone initially or combined with pegylated-interferon-alfa-2a and ribavirin, was associated with early change in HCV RNA among treatment-naive participants with chronic genotype 4 hepatitis C. The primary endpoint and assay are specified, and the registry reports the study as randomized and completed. Those features describe the research question and measurement framework.

The registry record does not report the primary outcome estimates by arm. As a result, it does not establish the direction or size of the Day 15 changes, the amount of separation between regimens, or the precision of any comparison. It is not possible to decide from the endpoint definition whether the groups had similar or different results. A lack of a reported estimate cannot be treated as a finding of no effect, and no treatment conclusion follows from these details alone.

The secondary outcome list indicates that viral response, breakthrough, sustained response, relapse and pharmacokinetic measurements were of interest. Their results are not reported in the registry record. The serious and other adverse event counts are descriptive and based on the small at-risk groups recorded. They do not, by themselves, quantify comparative risk or provide a complete account of safety.

More generally, a clinical trial’s interpretation depends on outcome estimates, uncertainty, analysis populations, missing-data handling and a clear account of planned comparisons. The registry record does not report many of these details. The appropriate conclusion is therefore limited: the study evaluated early HCV RNA change and recorded adverse-event counts, but the available information is insufficient to characterize the efficacy comparison or draw firm comparative conclusions.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of how a defined biological endpoint and an exploratory randomized design are not enough, on their own, to support a quantitative comparison. The registry names a Day 15 change in HCV RNA, states its unit and summary statistic, and identifies the assay. Yet without arm-level estimates and measures of uncertainty, readers cannot determine what the observed changes were or how precisely the groups were compared.

The three-regimen structure also matters. A trial can ask several related questions: how an initial telaprevir period compares with placebo, how a combination regimen compares with placebo, or how the two telaprevir strategies compare with each other. Which contrasts were prespecified and how they were handled statistically affect interpretation, but those details are not reported in the registry record. The stated planning assumptions describe two-arm illustrations, while the study itself has three arms; that distinction cautions against treating general planning assumptions as a complete account of the design.

Small group counts make transparent reporting especially important. With 8 participants at risk in each group for the adverse-event summaries, event counts are useful descriptions but cannot by themselves provide precise estimates of differences. Clear reporting of outcome values, uncertainty, participant flow and missing-data handling would be necessary to judge the strength and limits of the evidence. The record’s endpoint definitions and group descriptions are useful, but they do not substitute for those results.

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 for interpreting this trial is that the registry record does not report the Day 15 median changes or full ranges by arm. It also does not report a treatment contrast, confidence interval or p-value for that endpoint. Without these quantities, the magnitude, direction and precision of the primary comparison cannot be assessed.

The study enrolled 24 participants and records 8 participants at risk in each arm for the adverse-event summaries. Such limited group counts constrain the precision of estimates, particularly for uncommon events. The registry record does not report baseline outcome distributions or group characteristics that would help assess comparability after randomization.

There is an inconsistency in how masking is described: the masking field says double, while the official title says partially blinded. The record does not clarify who was masked or how. The description of the telaprevir-first regimen is truncated, so its full later treatment schedule is not available. The randomization procedure, allocation ratio, adherence, withdrawals and protocol deviations are also not reported.

Although 12 outcome measures and 6 analyses are listed, the registry record does not explain the analysis methods, planned contrasts, multiplicity approach or how analyses correspond to outcomes. Missing measurements, imputation, sensitivity analyses and the number assessed for the primary outcome by arm are not reported. The death counts are null rather than stated as observed counts, and the serious adverse event term is not linked to a group in the information available. These limitations leave important uncertainty about efficacy, safety and the robustness of the reported summaries.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: An Exploratory Study of Telaprevir in Treatment-Naive Participants With Chronic Genotype 4 Hepatitis C Virus Infection — NCT00580801.
• Registry record last updated 2013-09-09; status last verified 2013-08.
• Results first posted 2013-07-12.
• 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

NCT00580801 is a completed randomized, parallel-group Phase IIa study of telaprevir in treatment-naive participants with chronic genotype 4 hepatitis C. Enrollment was 24. The three regimens involved telaprevir followed by pegylated-interferon-alfa-2a and ribavirin, telaprevir with both medicines, or matching placebo with both medicines.

The primary outcome was change from baseline in HCV RNA at Day 15, summarized as a median with a full range and measured using the COBAS TaqMan HCV test Version 2.0. The primary outcome values by arm are not reported in the registry record. The registry lists 12 outcome measures and 6 analyses, but does not report the detailed statistical methods or multiplicity approach.

For safety, 8 participants were at risk in each group. Serious adverse events affected 1 participant in the telaprevir-first group and 0 in each other group; other adverse events affected 8 participants in each group. Death counts are not reported in the registry record. The available information describes the trial question and endpoint but does not permit a quantitative interpretation of the primary treatment comparison.