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 Efficacy and Safety of MP-424, Peginterferon Alfa-2b and Ribavirin in Chronic Hepatitis C Who Have Not Achieved an Undetectable HCV RNA Level With Previous Interferon Based Therapy (NCT00781274), a na phase 3 study. The primary outcome is The Percentage of Subjects Achieving Undetectable Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) at 24 Weeks After Completion of Drug Administration (SVR, Sustained Viral Response).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00781274 |
| Phase | Phase 3 |
| Condition | Hepatitis C |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 32 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Tanabe Pharma Corporation |
| Results posted | Yes |
2. Clinical Question
Population
People with genotype 1 hepatitis C who did not respond to previous treatment are the stated study population. The title further describes people who had not achieved an undetectable HCV RNA level with previous interferon-based therapy. The registry record does not report further eligibility details or an analysis-population definition.
Intervention
The study evaluated MP-424 in combination with peginterferon alfa-2b and ribavirin. These are the three named drugs in the study description. The record does not give dose, schedule, treatment duration, or details of how treatment was administered.
Comparator
No separate control group is described. The record identifies a single-group model, and allocation is listed as not applicable. This means the study does not provide a randomized, like-for-like comparison with another treatment or with no treatment.
Primary question
The primary endpoint is the percentage of subjects with undetectable HCV RNA at 24 weeks after completing drug administration, described as sustained viral response. The registry record specifies a 95% confidence interval as the measure of dispersion, but does not report the observed endpoint value or its interval. The record therefore defines what was to be assessed, but does not establish the numerical result of that assessment.
3. Trial Design
This is a phase 3, single-group study sponsored by Tanabe Pharma Corporation. The registry record lists an enrollment of 32 and describes the intervention as MP-424 combined with peginterferon alfa-2b and ribavirin for people with genotype 1 hepatitis C who did not respond to previous treatment. The record lists Hepatitis C as the condition.
Allocation is listed as not applicable, the study model is single-group, and masking is listed as none. There is no separate comparator group in the trial description. Consequently, the endpoint is not a randomized contrast between the combination and another intervention. Any endpoint value would describe the enrolled group under the study treatment, rather than an estimated difference against a concurrent control.
The registry record lists the start as 2008-12, primary completion as 2010-07, and status as completed. These dates describe the registered study timeline; they do not supply information about treatment duration or the timing of individual participants’ follow-up. The record does not report the protocol’s detailed eligibility criteria, drug doses, treatment schedule, recruitment process, or statistical analysis plan. Those details should not be inferred from the study title or the listed endpoint.
The registry lists one primary outcome measure and zero analyses. The primary outcome is defined at 24 weeks after completion of drug administration. Its result is not reported in the registry record, so the design information alone cannot answer how many participants achieved that endpoint or how uncertain an observed estimate would be.
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
| Stage | MP-424 |
|---|---|
| STARTED | 32 |
| COMPLETED | 30 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | MP-424 |
|---|---|
| Withdrawal by Subject | 2 |
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 | MP-424 |
|---|---|---|
| Participants analysed | 32 | |
| Age, Continuous | years | 55.4 (SD 6.4) |
| Sex: Female, Male: Female | Participants | 15 |
| Sex: Female, Male: Male | Participants | 17 |
6. Primary Endpoint
The registry lists the primary outcome as The Percentage of Subjects Achieving Undetectable Hepatitis C Virus (HCV) Ribonucleic Acid (RNA) at 24 Weeks After Completion of Drug Administration (SVR, Sustained Viral Response), measured over After 24 weeks of follow-up.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage of subjects achieving SVR |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage of subjects whose HCV RNA was undetectable at 24 weeks after completion of drug administration. The record calls this sustained viral response, or SVR, and identifies the outcome unit as the percentage of subjects achieving SVR. It also specifies a 95% confidence interval as the dispersion measure.
In general, an endpoint translates a study question into a defined outcome that can be assessed for participants. Here, the endpoint combines a laboratory status—undetectable HCV RNA—with a specified follow-up point after treatment completion. The follow-up timing is part of the outcome definition; an RNA result at a different time would not be the same endpoint as the one registered.
A confidence interval, in general, describes the uncertainty around an estimated quantity. It is not a guarantee that the true value lies within the interval, and its interpretation depends on the analysis and assumptions used. Although the registry record identifies a 95% confidence interval for this endpoint, it does not report the endpoint estimate or the interval limits. The definition is therefore available, but the numerical outcome and its precision cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive limitation is that the registry record defines the primary outcome but does not report its observed value. It gives no count or percentage of participants who achieved undetectable HCV RNA at 24 weeks after completing drug administration, and it gives no confidence-interval limits. The endpoint description alone is not an efficacy result. Without the estimate and its uncertainty, the magnitude and precision of the registered primary outcome cannot be evaluated.
The design also limits what any reported single-group endpoint could establish. The study is listed as single-group, allocation is not applicable, and masking is listed as none. There is no registered randomized comparator in the trial description. A result from the treated group would therefore describe outcomes among those participants, but it would not by itself estimate how those outcomes differ from a concurrent control group. Differences from other studies or from an assumed benchmark would require additional information and assumptions not reported in the registry record.
The registry lists enrollment of 32. That is the registered enrollment figure; it should not be treated as the number included in a particular endpoint analysis, because the analysis population and the number with endpoint data are not reported. The record also does not state how missing outcome measurements were handled. As a result, the denominator and completeness of follow-up for the primary endpoint cannot be determined from this information.
The endpoint specifies a 95% confidence interval, but no interval is reported. General statistical interpretation distinguishes the estimated outcome from its precision: an estimate gives the observed result, while an interval conveys uncertainty under a stated method. Neither can be reconstructed from the endpoint definition or enrollment figure alone. No p-value or inferential test result is reported in the registry record.
The accompanying planning illustrations are not observed trial outcomes and do not substitute for a control group or for the missing endpoint estimate. Their assumptions concern a hypothetical two-arm design, equal allocation, a two-sided significance level of 0.05, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. They are planning calculations, not observed power and not a description of the registered single-group design. No numerical planning result is needed to interpret the registry endpoint.
Overall, the available record describes the question and broad design, but not the primary result. Statistical interpretation must therefore remain at the level of design and endpoint definition. It is not possible to judge the size or precision of the endpoint estimate, the completeness of its analysis, or a comparative treatment effect from the registry information.
9. Statistical Methods Explained
What does the endpoint estimate?
The registered primary outcome is a percentage: the percentage of subjects achieving undetectable HCV RNA at 24 weeks after completion of drug administration. In general, a percentage for a binary outcome is formed by identifying participants who meet the endpoint definition and relating that count to an analysis denominator. The registry record does not give either the primary outcome count or its analysis denominator. Enrollment of 32 does not establish that all enrolled participants contributed endpoint data.
The endpoint definition also includes the time of assessment. In general, measurements made at different follow-up times can answer different questions, so the stated 24-week point is part of what the outcome means. The record does not report individual follow-up completeness or whether any participants had measurements outside the planned time point.
What does a confidence interval communicate?
The registry identifies a 95% confidence interval as the dispersion measure for the primary outcome. In general, a confidence interval conveys the statistical uncertainty associated with an estimate under a particular method and its assumptions. It should be read alongside the point estimate: a precise estimate and an imprecise estimate can have the same central value but support different levels of certainty about the underlying quantity. The actual estimate and confidence interval are not reported in the registry record, and the interval method is not stated there.
For a percentage, methods must account for the fact that the outcome is bounded and arises from a count. Different interval methods can behave differently, particularly when data are sparse or the estimated percentage is near a boundary. This is general statistical context, not a claim about which method was used in this study. The registry record does not specify the method, so no method-specific interpretation is possible.
Why does the design matter?
The registry describes a single-group study with no allocation to a separate comparator and no masking. In general, random allocation to a concurrent control group supports a direct comparison by balancing measured and unmeasured factors in expectation. A single-group outcome instead describes the experience of the enrolled group. Without a concurrent comparison, the primary endpoint cannot on its own quantify a treatment contrast or distinguish the treatment’s contribution from other influences on outcomes.
Masking is listed as none. In general, lack of masking can matter when knowledge of treatment assignment may affect how outcomes are assessed, reported, or managed. The endpoint is described as a laboratory measure, but the registry record does not state how samples were processed, whether laboratory personnel were masked, or what procedures were used to limit assessment bias. Those details should not be assumed.
What do the planning calculations mean?
The planning illustrations use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe hypothetical participants per arm for non-time-to-event outcomes, with the effect to detect defined as a stated fraction of the observed effect. The registry’s primary endpoint is a percentage, not a time-to-event outcome. The illustrations are planning calculations, not observed power and not evidence about the actual study’s design. The assumptions are not reported as the trial’s own sample-size justification.
In general, planning calculations depend on the assumed effect, variability, significance level, allocation, and analysis method. Changing assumptions can change the resulting sample-size illustration. Such calculations do not reveal whether a study was adequately powered for its actual endpoint, especially when the trial’s own design assumptions and analysis plan are not reported. The registry record does not give a sample-size justification, target power, or an assumed endpoint rate.
How should the missing analysis details be read?
The registry lists zero analyses. That means the record does not present an analysis result to interpret; it does not establish which methods were used outside the registry record. The primary endpoint’s confidence-interval label is not a complete statistical analysis plan. The record does not specify the estimator, interval method, handling of missing outcomes, analysis population, or whether any adjustment was planned. General concepts can clarify why these decisions matter, but they cannot fill in the study-specific methods.
For example, an analysis population defines which participants contribute to an estimate, while missing-data rules determine how unavailable outcomes are treated. These choices can affect both the estimated percentage and its uncertainty. Because neither is reported, it is not possible to determine whether the registered enrollment and the endpoint denominator coincide, or whether participants without an observed endpoint were excluded or handled another way.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists one primary outcome measure and zero analyses. It does not report a statistical analysis plan, a list of secondary outcomes, or a testing hierarchy. Multiplicity concerns arise in general when several outcomes, time points, or comparisons are tested and the interpretation does not account for the number of tests. The available registry information is not sufficient to determine whether multiplicity adjustments were planned or used. No adjustment should be inferred from the fact that a primary endpoint is identified.
The record does not report missing-data procedures, the number of participants with a measured primary endpoint, or the analysis population. Enrollment is listed as 32, but enrollment alone does not establish how many participants were included in the endpoint analysis. In general, excluding participants without endpoint data or using an imputation method can affect both the estimate and its uncertainty. The registry record does not say whether either approach, or another approach, was used.
The primary outcome is defined at 24 weeks after completion of drug administration. The record does not describe how participants who did not complete drug administration, did not attend the follow-up assessment, or had an unavailable RNA result were handled. These are study-specific analysis details, not matters that can be resolved from the endpoint definition.
The registry identifies a 95% confidence interval as the dispersion measure but does not give the interval or its calculation method. It also does not report a p-value or analysis result. Consequently, multiplicity, missing-data handling, and analysis-population choices remain unreported in the registry record, and the primary estimate’s inferential basis cannot be independently assessed from this record.
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 |
|---|---|---|---|
| MP-424 | 3 | 32 | 9.4% |
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 |
|---|---|
| MP-424 | 32 of 32 |
Most frequent serious adverse event terms
| Event term | Organ system | MP-424 |
|---|---|---|
| Vomiting | Gastrointestinal disorders | 1 of 32 |
| Erythema nodosum | Skin and subcutaneous tissue disorders | 1 of 32 |
| Malaise | General disorders | 1 of 32 |
Most frequent non-serious adverse event terms
| Event term | Organ system | MP-424 |
|---|---|---|
| Anaemia | Blood and lymphatic system disorders | 32 of 32 |
| Pyrexia | General disorders | 30 of 32 |
| Blood uric acid increased | Investigations | 25 of 32 |
| Malaise | General disorders | 22 of 32 |
| White blood cell count decreased | Investigations | 22 of 32 |
| Platelet count decreased | Investigations | 22 of 32 |
| Rash | Skin and subcutaneous tissue disorders | 16 of 32 |
| Decreased appetite | Metabolism and nutrition disorders | 15 of 32 |
| Hyaluronic acid increased | Investigations | 15 of 32 |
| Blood creatinine increased | Investigations | 12 of 32 |
Serious events with the highest arm-level rate: vomiting (3.1%), erythema nodosum (3.1%), malaise (3.1%).
The registry reports a serious-adverse-event group titled MP-424, with 32 subjects at risk and 3 affected. It also reports 32 subjects at risk and 32 affected for other adverse events. These are distinct registry categories and should be read as reported; the record does not explain how the categories relate or whether individual participants could appear in both.
The listed top serious terms are vomiting, erythema nodosum, and malaise, each reported as 3.1%. The registry does not provide participant counts for each term in this listing, so those percentages should not be converted into counts. They are adverse-event listings, not estimates of comparative risk, because no separate control group is described.
Deaths are not reported in the registry record. The record does not provide further detail about event timing, severity grading, attribution, duration, or participant-level overlap. Serious adverse-event counts and other adverse-event counts describe safety reporting in this study; without a comparator and additional context, they do not establish a comparative safety effect.
12. What the Result Does, and Does Not, Mean
The registry record establishes the broad question studied: whether participants with genotype 1 hepatitis C who did not respond to previous treatment achieved undetectable HCV RNA at the specified follow-up after receiving MP-424 with peginterferon alfa-2b and ribavirin. It also establishes that the study was phase 3, single-group, and listed as completed, with enrollment of 32.
It does not report the primary endpoint result. There is no observed percentage, participant count for the endpoint, or confidence-interval limit in the registry record. Therefore, the record does not show the size or precision of the observed sustained viral response outcome. The endpoint label and study description cannot stand in for those missing results.
Even if a single-group endpoint estimate were available, it would describe outcomes in the study group rather than a randomized comparison. Because the record does not describe a separate control group, the endpoint alone would not estimate a difference between the combination and another treatment. It also would not resolve how outcomes might have differed under another care strategy. Such comparative interpretation requires evidence beyond a single-group result.
The safety information reports serious events and other adverse events in the MP-424 group, along with several serious-event terms. These figures describe the registry’s reported categories, but the record does not give a control-group comparison or the detailed context needed to interpret comparative safety. Deaths are not reported in the registry record.
In general, trial interpretation depends on the outcome estimate, its uncertainty, the analysis population, missing-data handling, and design. Several of these elements are not reported. The appropriate reading is therefore limited: the registry documents the intended endpoint, the broad design, and selected safety counts, but it does not provide the primary result needed to assess the endpoint’s observed magnitude or precision.
13. Why This Trial Matters Statistically
This trial is statistically notable for the gap between a clearly stated endpoint and the absence of a reported endpoint result in the registry record. The primary outcome is defined with a laboratory threshold and a specific follow-up time, and a 95% confidence interval is identified as the dispersion measure. Yet the observed percentage and interval are not reported. This illustrates why an endpoint definition and an outcome estimate are separate pieces of evidence.
The single-group design also shapes the question that can be answered. The registry describes one treatment group and no randomized comparator. A single-group estimate, if reported, would characterize outcomes among enrolled participants, but it would not supply a concurrent contrast. Statistical precision around a group estimate cannot by itself create a comparative effect estimate.
The record also distinguishes registered enrollment from a defined analysis population. Enrollment of 32 does not reveal how many participants contributed a 24-week outcome, and missing-data handling is not reported. These omissions matter because the denominator and analysis rules are part of interpreting a percentage and its uncertainty.
Finally, planning calculations are not trial results. The described planning assumptions—two-sided significance level 0.05, equal allocation between two arms, and normal approximation—concern an illustrative design, not the registered single-group study. Keeping planning assumptions separate from observed evidence helps prevent a hypothetical sample-size calculation from being mistaken for an analysis of the study’s outcomes.
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 registry record does not report the observed primary endpoint value or its 95% confidence interval. This prevents assessment of the endpoint’s magnitude and statistical precision. Although enrollment is listed as 32, the number included in the primary endpoint analysis and the number with available outcome data are not reported.
The study is described as single-group, with allocation not applicable and no masking. No separate control group is described, so the registry record does not support a randomized comparison. The record does not provide enough detail to assess how the absence of masking may have affected study conduct or outcome assessment.
Important operational details are not reported, including drug doses, treatment schedule, treatment duration, detailed eligibility criteria, and follow-up completeness. The record does not specify an analysis population, missing-data procedures, the confidence-interval method, or a broader statistical analysis plan. It also does not report a sample-size justification or the assumptions used to plan the trial.
Safety information is limited to the listed counts and serious-event terms. The record does not provide event timing, attribution, severity grading beyond the serious classification, participant-level overlap, or a comparator group. Deaths are not reported in the registry record. These limitations constrain interpretation of both the primary endpoint and the safety information; they should not be filled by assumptions about the protocol or analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Efficacy and Safety of MP-424, Peginterferon Alfa-2b and Ribavirin in Chronic Hepatitis C Who Have Not Achieved an Undetectable HCV RNA Level With Previous Interferon Based Therapy — NCT00781274.
- Registry record last updated 2026-01-06; status last verified 2025-12.
- Results first posted 2012-08-20.
- 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
The registry record describes a completed phase 3, single-group study sponsored by Tanabe Pharma Corporation. It lists enrollment of 32, a start of 2008-12, and primary completion of 2010-07. The intervention was MP-424 with peginterferon alfa-2b and ribavirin for people with genotype 1 hepatitis C who did not respond to previous treatment.
The primary endpoint was the percentage of subjects with undetectable HCV RNA at 24 weeks after drug administration, described as sustained viral response. A 95% confidence interval is identified, but the endpoint estimate and interval are not reported in the registry record. The record lists zero analyses and does not report the analysis population or missing-data procedures.
For safety, the registry reports 3 serious adverse-event-affected subjects among 32 at risk and 32 other-adverse-event-affected subjects among 32 at risk. Vomiting, erythema nodosum, and malaise are each listed at 3.1% among the top serious terms. Deaths are not reported in the registry record.