A Phase 2a Study to Evaluate Viral Kinetics and Safety of Telaprevir in Participants With Genotype 2 or 3 Hepatitis C Infection: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Phase 2a Study to Evaluate Viral Kinetics and Safety of Telaprevir in Participants With Genotype 2 or 3 Hepatitis C Infection (NCT00561015), a randomized phase 2 study. The primary outcome is Change From Baseline in Log 10 Plasma Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) Level at Day 15.

2. Clinical Question

The study was intended to assess early hepatitis C virus (HCV) viral kinetics and safety in participants who had not previously been treated for chronic infection. Viral kinetics refers, in general, to how virus levels change over time. The primary endpoint focuses on the early change in the amount of HCV RNA in plasma, rather than on a longer-term clinical outcome.

The posted arms include telaprevir followed by peginterferon alfa-2a and ribavirin, telaprevir given with those medicines, and placebo given with them. These approaches are listed for both genotypes. The registry record describes random assignment and a parallel-group design. It does not report a single pooled treatment contrast, nor does it specify which pairwise comparison should be treated as the principal comparison for interpreting the primary endpoint.

The listed secondary outcomes include HCV RNA change at Week 24 and Week 26, virological response, time to response, viral breakthrough, and virological relapse, as well as measures of telaprevir concentration. Their presence indicates that the study record names outcomes beyond the Day 15 endpoint; it does not supply results for those outcomes.

3. Trial Design

The registry identifies this as a Phase 2a study, with the official title describing it as a Phase IIa randomized, partially blinded trial. The registry's masking entry says double. The exact masking procedures and which people were masked are not reported in the registry record, so the difference in wording cannot be resolved from the available description.

The design is listed as randomized and parallel. Participants were treatment-naive and had chronic genotype 2 or genotype 3 hepatitis C. Enrollment was 52. The record lists a start date of 2007-12, a primary completion date of 2008-06, and a completed status.

Arms are listed within each genotype. One approach used telaprevir 750 mg orally 3 times a day from Day 1 to Day 15, followed by standard treatment. Another combined telaprevir with peginterferon alfa-2a and ribavirin. A placebo approach combined matching placebo with peginterferon alfa-2a and ribavirin. The descriptions identify the standard-treatment medicines but do not fully report all treatment durations in every arm description.

The primary endpoint is described as the median change from baseline in log10 plasma HCV RNA at the pre-dose Day 15 assessment, with full range as the dispersion measure. The record defines a full analysis set as randomly assigned participants who received at least 1 dose of telaprevir or placebo. It does not report the number analyzed for the primary endpoint, the allocation ratio, or the number assigned to each group.

The registry record does not report a sample-size justification, a detailed statistical analysis plan, interim analyses, or a prespecified hierarchy of treatment comparisons. It lists 13 outcome measures and zero analyses. Thus, the record supports a description of the planned design and outcome definitions, but not a reconstruction of the analysis plan or a result-based assessment of treatment differences.

4. Participant Flow and Accounting

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

Before assignment: Out of 26 participants infected with genotype 2 hepatitis C virus (HCV) who were randomly assigned to treatment, only 23 participants received treatment. 2 participants withdrew and 1 participant was infected with HCV genotype 4. All the 26 participants infected with genotype 3 HCV received treatment.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full analysis set (FAS) population included all randomly assigned participants who received at least 1 dose of TVR or placebo.

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.

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in Log 10 Plasma Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) Level at Day 15, measured over Baseline, Pre-dose (Day 15).

The primary endpoint is the change from baseline in log10 plasma HCV RNA at the pre-dose Day 15 assessment. HCV RNA is a measure of the amount of hepatitis C virus genetic material detected in plasma. The record specifies that the endpoint is summarized by the median and full range, rather than by a mean and a standard deviation.

In general, measuring change from baseline expresses how an individual's measured value differs from their own starting value. This can help describe early movement in viral levels during treatment. The log10 scale represents viral RNA on a logarithmic scale; a change on that scale is not expressed in the same units as a direct change in the untransformed RNA concentration. No transformation of the reported values can be assessed because the endpoint results are not reported in the registry record.

The assay is identified as the COBAS TaqMan HCV test v2.0, using reverse transcription-polymerase chain reaction methodology. The record states a lower limit of quantification of 25 IU/ml and a limit of detection of 10 IU/ml. These are assay characteristics, not the study's observed endpoint values. In general, an assay's limit of quantification describes the lower range at which an amount can be quantified, while its limit of detection describes the lower range at which a signal can be detected.

An early viral RNA change is useful for describing viral kinetics, the stated focus of the study. It does not, by itself, give a longer-term treatment outcome. The registry also lists later viral RNA assessments and response, breakthrough, and relapse outcomes, but does not report their results. The Day 15 endpoint therefore needs to be interpreted as an early laboratory measure, not as a substitute for outcomes that the record does not report.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a change score on the log10 scale, summarized using the median and full range. In general, a change score compares a follow-up measurement with a baseline measurement for the same participant. Such a measure is intended to represent movement from the participant's starting value, but interpretation depends on how baseline and follow-up values were recorded and analyzed. The registry names the endpoint and assessment time but does not report the individual or group values.

A median is the central ordered observation: half the observed values lie on either side of it, allowing for the usual treatment of ties. It is less affected by extreme observations than a mean. A full range gives the endpoints of the observed values and can be sensitive to unusually high or low observations. Neither summary alone quantifies uncertainty in a treatment contrast. A confidence interval for a contrast, or a suitable statistical test, would be needed to assess the estimated difference and its precision. The record does not report such an analysis.

The endpoint is measured on a log10 scale. In general, logarithmic scales are useful when values span a broad range, because equal distances on the scale represent multiplicative rather than additive changes in the original measurement. The exact interpretation of a log-scale difference depends on the data and analysis. No numerical endpoint estimate is available in the registry record, so no conversion or magnitude interpretation is warranted.

The assay description gives a lower limit of quantification of 25 IU/ml and a limit of detection of 10 IU/ml. In general, values near or below assay limits can require explicit handling rules: a laboratory may detect a signal without being able to quantify it reliably, and values below a limit may be censored or assigned a value for analysis. The registry record does not state how measurements below either assay limit were handled in the primary analysis. This matters because the rule can affect summaries and comparisons, particularly when measurements cluster near a threshold.

The registry defines the full analysis set as randomly assigned participants who received at least 1 dose of telaprevir or placebo. In general, analysis-population definitions specify which participants' data contribute to a result. The stated definition is not identical to a complete intention-to-treat definition that includes all randomized participants regardless of treatment received, because receipt of a dose is part of the stated criterion. The record does not report how many participants met the definition, whether all such participants had Day 15 measurements, or whether other analysis populations were used.

Randomization is intended, in general, to reduce systematic differences between assigned groups by allocating participants through a chance process. Its usefulness for interpreting comparisons also depends on preserving the assigned groups in analysis and accounting for missing observations. The record states that the trial was randomized but does not report the allocation procedure, concealment process, or a detailed analysis plan. It is therefore not possible to evaluate those implementation details from this record.

Masking can reduce the influence of expectations on participant behavior, clinical management, and outcome assessment. The official title describes the study as partially blinded, while the masking entry identifies it as double. The record does not explain who was masked, whether masking applied to all treatment groups, or how it was maintained. These details are important for assessing the possibility of bias, but should not be inferred from the label alone.

Multiplicity arises when many outcomes, time points, groups, or pairwise comparisons are tested. In general, testing many hypotheses without a plan to control or interpret the overall error rate can increase the chance of at least one apparently notable result occurring by chance. This trial record lists 13 outcome measures, including multiple time points and several virological outcomes, but it does not report a multiplicity strategy, a primary comparison hierarchy, or analysis results. No inference about adjusted or unadjusted significance can be made.

For a count outcome or a time-to-event outcome, the suitable method depends on the event definition, follow-up, censoring, and comparison of interest. The record lists viral breakthrough, virological relapse, and median time to virological response among secondary outcomes, but supplies no event data or analysis details. The assumptions and methods for those analyses are not reported in the registry record. More generally, statistical methods cannot be reconstructed from outcome labels alone; the model, estimand, covariates, missing-data approach, and treatment of multiple tests would need to be documented.

The registry record lists zero analyses. This means it contains no recorded analysis results for interpretation in this account; it does not establish that no analyses were performed outside the registry record. There is no sponsor analysis to compare with a recalculation, and no basis for estimating a treatment effect from the posted information. Any planning illustration based on an observed effect would likewise lack the required observed estimate and should not be read as observed power.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 13 outcome measures, including the Day 15 primary endpoint, later HCV RNA changes, drug concentration measures, and several virological outcomes. Multiple outcomes and time points create a multiplicity issue when formal statistical tests are performed. In general, a prespecified testing hierarchy or other adjustment can define how results should be interpreted while limiting the risk of chance findings across many tests. The record does not report such a plan, the number of planned comparisons, or any multiplicity adjustment.

The record lists zero analyses, so it contains no reported test results or effect estimates for the outcomes. It is not possible to determine whether any analysis was conducted elsewhere, whether any result was adjusted, or whether the listed outcomes were all tested. The order in which outcomes appear does not establish a statistical testing hierarchy beyond the endpoint labeled primary.

The primary analysis population is defined as randomly assigned participants who received at least 1 dose of telaprevir or placebo. The number included in this population, the number with a Day 15 measurement, and the amount or pattern of missing endpoint data are not reported in the registry record. The missing-data method, including whether any imputation or sensitivity analysis was used, is also not reported in the registry record.

In general, missing outcome data can affect a comparison if the likelihood of being observed is related to treatment or to the unobserved outcome. An analysis population definition does not by itself explain how missing values were handled. Without participant flow, available-case counts, and the analysis method, the completeness and robustness of the primary endpoint analysis cannot be assessed.

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 non-serious adverse event terms

The safety listing separates serious adverse events from other adverse events and gives a number at risk and a number affected for each group. The serious adverse event count affected is 0 in every listed group: TVR then peginterferon alfa-2a plus ribavirin, genotype 2, had 9 at risk; TVR with those medicines, genotype 2, had 5 at risk; placebo with those medicines, genotype 2, had 9 at risk; TVR then standard treatment, genotype 3, had 8 at risk; TVR with standard treatment, genotype 3, had 9 at risk; and placebo with standard treatment, genotype 3, had 9 at risk.

For other adverse events, the listed at-risk and affected counts are 9 and 6 for the genotype 2 telaprevir-then-standard-treatment group; 5 and 4 for the genotype 2 telaprevir-with-standard-treatment group; and 9 and 8 for the genotype 2 placebo-with-standard-treatment group. For genotype 3, the corresponding counts are 8 and 7, 9 and 9, and 9 and 8.

These are descriptive counts, not rates or comparative risk estimates. No percentages should be inferred without a defined denominator and analysis. Death counts are not reported in the registry record. The listing does not establish causality or provide a basis for comparing safety across groups.

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

The registry record establishes that this was a randomized Phase 2a study intended to examine early HCV viral kinetics and safety in treatment-naive participants with chronic genotype 2 or 3 infection. It specifies a Day 15 change in log10 plasma HCV RNA as the primary endpoint and names several secondary outcomes. Those details explain what the study set out to measure; they do not reveal the observed effect.

The primary endpoint result is not reported in the registry record. There is no group-specific median change, full range, treatment contrast, uncertainty interval, or statistical test. Consequently, the direction, size, and precision of any difference cannot be described. The posted information does not establish whether any treatment approach was associated with a larger or smaller Day 15 change than another.

In general, an early change in a laboratory marker can characterize short-term biological response, but it does not by itself establish a longer-term outcome. The record lists later viral RNA assessments and outcomes such as virological response, breakthrough, and relapse, but does not give their results. The Day 15 endpoint should therefore be interpreted as a measure of early viral kinetics, not as evidence about outcomes that are absent from the record.

The safety counts indicate that no serious adverse events were recorded as affected in the listed groups, while other adverse events were recorded in each group. These counts are not adjusted comparisons, and the record does not provide death counts. They should not be interpreted as proof of equal safety, absence of risk, or a causal treatment effect.

Overall, the registry record supports a description of the study question, design, endpoint, analysis-population definition, and selected adverse-event counts. It does not support a conclusion about efficacy, statistical significance, comparative safety, or the precision of a treatment effect. Those conclusions would require reported outcome results and adequate analysis details.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of an early viral-kinetics question framed around a laboratory endpoint. The primary outcome is a change from baseline in log10 plasma HCV RNA measured at a specified early assessment. Defining the time point, measurement scale, and summary statistic helps clarify the intended quantity, even when the registry does not report its value.

The study also illustrates why a treatment label is not enough to identify a single estimand or comparison. The registry lists approaches that differ in whether telaprevir is used before standard treatment, combined with standard treatment, or replaced with placebo alongside standard treatment. These approaches are listed separately by genotype. Without a stated primary contrast and reported results, the reader cannot turn the arm descriptions into one definitive comparison.

The record includes a defined analysis population and assay limits, both relevant to interpretation. The population definition indicates that receipt of at least 1 dose was required. The assay's limit of quantification and limit of detection raise a general analytical consideration: values close to measurement thresholds may need a prespecified handling rule. That rule is not documented in the registry record.

Finally, the gap between outcome definitions and outcome reporting is important. The registry names multiple secondary outcomes but lists zero analyses. Statistical interpretation depends not only on what was measured, but also on the observed values, the comparison plan, uncertainty estimates, handling of missing data, and treatment of multiple outcomes. Without these, the record can describe the design but cannot answer the comparative question statistically.

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 interpreting this trial record is the absence of primary endpoint results. Although the endpoint and its summary format are defined, no median, full range, group comparison, confidence interval, or test result is reported. The listed secondary outcomes also lack reported results, so neither early nor later virological findings can be evaluated.

The comparison structure is not fully resolved in the record. Genotype-specific arms describe telaprevir followed by standard treatment, telaprevir with standard treatment, and placebo with standard treatment, but no single primary contrast is specified in the reported information. The official title says partially blinded, while the masking entry says double; the exact scope of masking is not reported in the registry record.

Important analysis details are also absent. The record does not report the allocation ratio, group-specific enrollment, number with endpoint data, missing-data approach, imputation rules, model or test, adjustment for multiple comparisons, or a sample-size justification. It does not explain how measurements below the assay limits were handled. These omissions prevent evaluation of analysis assumptions and the robustness of any result.

The safety information is limited to counts at risk and affected for serious and other adverse events in the listed groups. Death counts are not reported in the registry record, and no comparative safety analysis is given. The counts alone cannot establish causality or quantify comparative risk.

Finally, the arm descriptions do not fully report treatment durations in every group. The record supports the stated early dosing schedule for telaprevir, but does not provide enough detail to reconstruct every treatment course or analysis population beyond the stated full analysis set definition.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Phase 2a Study to Evaluate Viral Kinetics and Safety of Telaprevir in Participants With Genotype 2 or 3 Hepatitis C Infection — NCT00561015.
• Registry record last updated 2013-06-17; status last verified 2013-06.
• Results first posted 2013-06-04.
• 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

This completed Phase 2a randomized parallel-group study enrolled 52 treatment-naive participants with chronic genotype 2 or genotype 3 hepatitis C. The registry record lists telaprevir, peginterferon alfa-2a plus ribavirin, and placebo across genotype-specific treatment approaches.

The primary endpoint was median change from baseline in log10 plasma HCV RNA at the pre-dose Day 15 assessment, with full range as the dispersion measure. The assay was COBAS TaqMan HCV test v2.0. The full analysis set was defined as randomly assigned participants who received at least 1 dose of telaprevir or placebo.

The record lists 13 outcome measures and zero analyses. Primary and secondary efficacy results, statistical comparisons, missing-data methods, and multiplicity procedures are not reported in the registry record. Safety listings report zero serious adverse events affected in each displayed group and provide counts for other adverse events; deaths are not reported.