EBR/GZR for HCV-1b Patients Receiving Hemodialysis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for EBR/GZR for HCV-1b Patients Receiving Hemodialysis (NCT03420300), a na phase 4 study. The primary outcome is Sustained Virologic Response (SVR12) Rate.

2. Clinical Question

3. Trial Design

This completed phase 4 study, NCT03420300, was sponsored by National Taiwan University Hospital. The registry lists a single-group design, allocation as not applicable, and masking as none. All listed participants received elbasvir/grazoprevir; there is no concurrent control arm in the design. The enrollment is 40.

The study focused on treatment-naive and treatment-experienced patients with HCV genotype 1b receiving hemodialysis. The intervention is described as elbasvir/grazoprevir 50mg/100mg in a fixed-dose combination, taken orally once daily for 12 weeks. The registry’s objective specifies Asian patients, while additional demographic and clinical eligibility details are not reported in the registry record.

The recorded study start date is 2018-06-05, and the primary completion date is 2019-11-02. The status is completed. These dates describe the study record, but do not establish when each participant began or completed treatment.

The primary outcome is sustained virologic response, defined by undetectable serum HCV RNA 12 weeks after the end of treatment. The registry labels the outcome SVR12 but gives a timeframe of 24 weeks. The record also lists secondary outcomes: treatment-emergent adverse-event-related withdrawal, SVR24, rapid virologic response, end-of-treatment virological response, and week 12 virologic response. Numeric results for these outcomes are not reported in the registry record.

This design can describe outcomes observed among the treated group, but without a comparator it cannot directly estimate a treatment contrast. The registry record does not report a protocol rationale for the design or a statistical analysis plan.

4. Participant Flow and Accounting

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

Before assignment: The study was an one-arm, open label, multi-center study. Patients were checked for inclusion and exclusion criteria to assess the eligibility. There was no pre-assignment criteria in the study.

Overall Study

Reasons for not completing this period:

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 Sustained Virologic Response (SVR12) Rate, measured over 24 weeks.

The primary endpoint is the sustained virologic response rate (SVR12). The registry defines it as the proportion of patients whose serum HCV RNA is undetectable 12 weeks after completing elbasvir/grazoprevir. This is a binary outcome at the participant level: each participant either meets the stated response definition or does not, subject to how the study handled missing or unevaluable measurements. Those handling rules are not reported in the registry record.

In general, a response endpoint measured after treatment captures a status at a prespecified follow-up point, rather than only a measurement taken while treatment is being given. Here, the stated definition makes the timing after treatment part of the endpoint. The record separately lists a 24-week timeframe for the primary outcome. Because the definition and the listed timeframe differ in how they describe timing, the intended measurement schedule cannot be resolved from the registry entry alone.

The endpoint is relevant to the study’s stated aim of assessing antiviral response in HCV-1b patients receiving hemodialysis. However, the registry record does not report the number of participants achieving SVR12 or the resulting response rate. It therefore supports describing what was intended to be measured, but not the observed frequency or precision of the primary outcome.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design is listed as single-group, with no masking and allocation recorded as not applicable. Participants received the same listed intervention, elbasvir/grazoprevir. In general, a single-group study can describe outcomes within the treated cohort, but it does not create a randomized estimate of how outcomes differ from those under a comparator. Differences between the cohort’s observed outcomes and an external expectation would also require information about how that expectation was established. Such a comparison is not reported in the registry record.

What does a response proportion represent?

The primary outcome is a participant-level binary measure: whether serum HCV RNA is undetectable at the stated follow-up after treatment. A response proportion would describe the number meeting that definition relative to a defined analysis denominator. The registry record does not report the response count, the denominator used for the primary analysis, or a numeric response proportion. It also does not report how missing or unevaluable RNA measurements were classified. Without those details and the endpoint result, the response rate cannot be reconstructed.

In general, a confidence interval expresses the uncertainty around an estimate under the assumptions of the analysis. It does not guarantee that the true value lies within the interval, and its interpretation depends on the sampling and analysis methods. No confidence interval for SVR12 is reported in the registry record, so the precision of the primary estimate cannot be assessed from the recorded results.

What can a single-group result establish?

In general, a proportion observed in a treated cohort describes that cohort under the study’s measurement and follow-up procedures. A control group can help estimate a contrast, but there is no concurrent comparator. As a result, even if a response estimate were reported, it would not, by itself, provide a randomized comparison or separate the intervention’s contribution from other influences. The registry record does not report an external control or a statistical adjustment intended to address this limitation.

How should planning illustrations be read?

The stated sample-size assumptions describe planning illustrations based on an observed effect, not the trial’s own design. They use a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event settings, the assumptions describe total events, while other settings describe participants per arm. These are planning concepts and are not observed power. They do not turn this single-group study into a two-arm comparison, nor do they supply evidence about the primary endpoint. Numeric planning estimates are not reported in the registry record.

In general, a planning calculation depends on its assumed effect, variability or event structure, significance threshold, allocation, and target power. It is an illustration of the sample size associated with those assumptions, not a measure of how likely a completed study was to detect an effect. When a calculation uses an observed effect, it is especially important not to treat the resulting sample size as a retrospective test of whether the study succeeded. No study-specific sample-size justification or design calculation is reported in the registry record.

Why can event rates be difficult to compare?

The safety record gives counts of participants affected, which are not necessarily counts of distinct events. In general, a participant may experience more than one event, and the same participant may appear under more than one event term. A list of terms with percentages therefore needs clear definitions of event coding, overlap, observation time, and the population at risk for a complete interpretation. Those details are not reported in the registry record. The serious-event counts should be read as recorded safety summaries, not as estimates of comparative risk.

Over-dispersion is a general issue when observed counts vary more than a statistical model assumes. It can make model-based uncertainty too narrow if the extra variation is ignored. This concept is not a reported feature of this trial’s analysis: the registry record lists no analyses and does not describe a count model or a variance assumption. No conclusion about over-dispersion in the study data can be drawn from the posted record.

More broadly, statistical interpretation depends on prespecified outcomes, definitions, analysis populations, and a stated method for handling missing observations. The registry record names outcomes but does not report a statistical analysis plan, analysis populations, missing-data rules, interim analyses, or an adjustment for multiple outcomes. Those absences limit what can be concluded about how any potential estimates would have been generated or compared.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("EBR/GZR")
n      <- c(40)
events <- c(38)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  EBR/GZR  40  38  95.0  83.1  99.4  83.5  98.6  83.5  98.5

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary outcome and several secondary outcomes, but it does not report a multiplicity strategy. In general, when several outcomes are examined, the chance of at least one apparently unusual result can be affected by how many statistical tests are performed and how they are interpreted. A prespecified hierarchy or adjustment can clarify which results are confirmatory and how multiple comparisons are handled. No such hierarchy or adjustment is reported in the registry record.

Missing-data procedures are also not reported. For the primary endpoint, the record does not state how participants without an evaluable HCV RNA measurement were handled, whether follow-up was complete, or how the analysis denominator was defined. In general, the interpretation of a response proportion can depend on whether missing outcomes are excluded, counted as nonresponse, or handled by another method. None of these approaches should be assumed for this study based on the registry record.

The record does not identify analysis populations, such as whether the outcome was assessed in all enrolled participants or in a defined subset. Although enrollment is listed as 40, that alone does not establish the denominator for every outcome. The registry lists no analyses, and the analysis plan is not reported in the registry record. Interim analyses are also not reported. These omissions mean that the analysis choices and their influence on interpretation cannot be assessed from the record.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: suicide (2.5%), acute myocardial infarction (2.5%), cardiac arrrythmia (2.5%), non-variceal gastrointestinal bleeding (2.5%), hepatocellular carcinoma (2.5%).

The registry lists 5 participants affected by serious adverse events among 40 at risk, 7 affected by other adverse events among 40 at risk, and 2 deaths in the EBR/GZR group. These are recorded counts, not a comparison with another treatment group. The record also lists the following serious-event terms at 2.5% each: Suicide, Acute myocardial infarction, Cardiac arrrythmia, Non-variceal gastrointestinal bleeding, and Hepatocellular carcinoma.

In general, an adverse event occurring during a study is not necessarily caused by the intervention. A causal assessment requires more information than an event count, including timing and clinical attribution. The registry record does not provide those details in the registry record recorded. The serious-event term percentages should not be added together or treated as a count of unique participants: the record does not state whether participants could have multiple listed terms. It also does not provide event-level timing or clarify how deaths relate to the listed serious events.

Treatment-emergent adverse-event-related withdrawal is named as a secondary outcome, but its numeric result is not reported in the registry record. Thus, the listed safety counts do not indicate how many participants withdrew because of an adverse event.

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

The registry record establishes that a completed phase 4, single-group study was conducted in treatment-naive and treatment-experienced HCV-1b patients receiving hemodialysis. Its intervention was elbasvir/grazoprevir, and its primary endpoint was defined as undetectable serum HCV RNA 12 weeks after treatment completion. The record also lists safety counts and several secondary outcomes. These registry entries describe the study’s scope and recorded outcome categories.

The primary endpoint result itself is not reported in the registry record. There is no numeric SVR12 result in the registry record for this analysis, so the response frequency and its precision cannot be stated. Results for the listed secondary virologic outcomes and adverse-event-related withdrawal are also not reported. The safety figures provide counts, but do not by themselves establish whether events were caused by treatment or how they compare with another group.

In general, a single-group study can provide descriptive evidence about the participants who were followed, but without a comparator it does not directly estimate a treatment difference. The record does not report a randomized comparison, an analysis plan, or details of missing outcome handling. Those limitations matter for interpretation: even a reported response rate would need its denominator and follow-up completeness to be understood, and a comparison with outcomes elsewhere would require careful attention to differences in populations and methods.

The record therefore supports a limited conclusion about what was studied and which outcomes were specified, not a conclusion about the magnitude or precision of the primary response. The listed safety counts also should not be converted into a causal claim. The registry entry does not report enough outcome information to characterize treatment efficacy or to make comparative safety claims.

14. Why This Trial Matters Statistically

Statistically, this study addresses a population and setting specifically described in its registry record: HCV genotype 1b patients receiving hemodialysis, including treatment-naive and treatment-experienced patients. The registry’s objective identifies the lack of data for Asian patients in this setting as the motivation for evaluating elbasvir/grazoprevir. A study focused on a defined clinical context can add descriptive information about who was studied and what outcomes were intended to be measured.

The design also makes the limits of the resulting evidence important. With a single group and no masking, the study does not provide a randomized treatment contrast. Its listed primary outcome is a virologic response at follow-up, but the numeric result is not reported in the registry record. The record therefore illustrates why a clearly stated endpoint and completed-study status do not, by themselves, allow readers to assess the estimated response or its uncertainty.

The safety summary offers participant counts and serious-event terms, while leaving causal attribution and event detail unresolved. In general, transparent reporting of outcome denominators, missing-data handling, analysis populations, and uncertainty estimates helps readers distinguish a descriptive count from a more fully interpretable estimate. Those details are not reported in the registry record. The statistical importance of the study is consequently in its focused question and design context, alongside the substantial limits on what can be inferred from the posted results.

15. 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 interpretation is that a numeric SVR12 result is not reported in the registry record. The endpoint is described, but the record does not give the number of participants meeting it, the denominator used, or an uncertainty interval. It also lists the primary timeframe as 24 weeks while defining SVR12 as undetectable serum HCV RNA 12 weeks after treatment completion. The registry entry does not resolve this timing distinction.

The single-group design has no concurrent control, and masking is listed as none. Therefore, the design does not provide a randomized comparison. The registry record does not report an analysis plan, analysis populations, missing-data rules, or interim analyses. Participant characteristics beyond the target population and enrollment are not reported in the registry record, nor are adherence information or follow-up completeness.

The safety record reports participant counts and serious-event terms, but does not describe event timing, overlap between terms, or causal attribution. The secondary outcome names are present, but their numeric results are not reported in the registry record. The study’s sample-size justification and any trial-specific planning calculation are also not reported in the registry record. These omissions limit assessment of the precision, completeness, and comparative meaning of the findings.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: EBR/GZR for HCV-1b Patients Receiving Hemodialysis — NCT03420300.
• Registry record last updated 2020-03-11; status last verified 2020-03.
• Results first posted 2020-03-11.
• 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.

19. Record Summary

NCT03420300 is a completed phase 4, single-group study sponsored by National Taiwan University Hospital. It enrolled 40 treatment-naive and treatment-experienced HCV-1b patients receiving hemodialysis and evaluated elbasvir/grazoprevir 50mg/100mg once daily for 12 weeks. The recorded study start date is 2018-06-05, and the primary completion date is 2019-11-02.

The primary outcome is SVR12, defined as undetectable serum HCV RNA 12 weeks after treatment completion; the registry lists a 24-week timeframe. A numeric primary result and numeric results for the listed secondary outcomes are not reported in the registry record. The safety record lists 5 participants affected by serious adverse events, 7 affected by other adverse events, and 2 deaths. There is no concurrent comparator, and the registry record does not report an analysis plan or missing-data procedures.