A Study to Evaluate the Safety and Efficacy of Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir With Ribavirin in Adults With Genotype 1 and Ombitasvir/Paritaprevir/Ritonavir With Ribavirin in Adults With Genotype 4 Chronic Hepatitis C Virus Infection and Decompensated Cirrhosis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Evaluate the Safety and Efficacy of Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir With Ribavirin in Adults With Genotype 1 and Ombitasvir/Paritaprevir/Ritonavir With Ribavirin in Adults With Genotype 4 Chronic Hepatitis C Virus Infection and Decompensated Cirrhosis (NCT02219477), a non-randomized phase 3 study. The primary outcome is Percentages of Participants With Sustained Virologic Response 12 Weeks Post-Treatment (SVR12) in Group 1 and in Group 2.

2. Clinical Question

The study examined antiviral treatment in adults with chronic hepatitis C virus infection and decompensated cirrhosis. Its primary objectives were to assess safety and the SVR12 rate for participants with genotype 1 infection. The registry record also describes a genotype 4 group and lists SVR12 in that group as a secondary outcome.

3. Trial Design

TURQUOISE-CPB was a Phase 3, open-label, non-randomized, parallel-group study sponsored by AbbVie. The registry lists an enrollment of 36 and describes three groups organized by hepatitis C virus genotype and subtype: Group 1: GT1B, Group 2: GT1 Non-B, and Group 3: GT4. The record marks the study as completed.

Participants in Group 1 received ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily, dasabuvir 250 mg twice daily, and ribavirin for 12 weeks. Group 2 received the same medicines and doses for 24 weeks. Group 3 received ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily with ribavirin for 24 weeks. The registry does not specify the ribavirin dose in these descriptions.

Because allocation was non-randomized and the groups were defined by genotype, differences between groups cannot be interpreted as treatment effects from a randomized comparison. The groups also received different durations or combinations of treatment. The registry record itself cautions that the arms are not a like-for-like control comparison.

The study started on 2014-11-24, and primary completion is recorded as 2016-06-13. The primary outcome was SVR12 in Groups 1 and 2, assessed 12 weeks after the last actual dose of study drug. SVR12 in Group 3 and several virologic and liver-related outcomes were listed as secondary outcomes. The registry record does not report the protocol’s sample-size justification or a broader 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent to treat population: all participants who received at least 1 dose of study drug; participants missing data = non-responders. See imputation details in the outcome measure description.

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 Percentages of Participants With Sustained Virologic Response 12 Weeks Post-Treatment (SVR12) in Group 1 and in Group 2, measured over 12 weeks after the last actual dose of study drug.

The primary endpoint was the percentage of participants in Group 1 and Group 2 with sustained virologic response 12 weeks after the last actual dose of study drug. SVR12 was defined using hepatitis C virus RNA measurements in the SVR12 assessment window: RNA had to be below the lower limit of quantification, with no confirmed quantifiable post-treatment value before or during that window.

This endpoint summarizes whether viral RNA was detected at a defined post-treatment assessment. It is not a direct measure of every aspect of liver function or safety. The registry record specifies an intent-to-treat population, including all participants who received at least 1 dose; participants with missing data were counted as non-responders after the described imputation steps.

Using a defined post-treatment window makes the endpoint’s timing explicit, while the RNA criterion sets the response definition. The registry record states that the 95% confidence interval was calculated with the Wilson score method. A confidence interval describes uncertainty around an estimated percentage; it does not remove uncertainty from the non-randomized design. Although the endpoint definition is recorded, the SVR12 percentages and their confidence intervals are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The main statistical quantity specified for the primary endpoint is a percentage: the number of participants meeting the SVR12 definition relative to the intent-to-treat population. A percentage describes the observed proportion in a group. Its interpretation depends on both the outcome definition and who was included in the denominator. In this trial, the registry record defines the primary population as all participants who received at least 1 dose of study drug.

What does the confidence interval describe?

The registry specifies a 95% confidence interval calculated with the Wilson score method. In general, a confidence interval expresses the precision of an estimate by giving a range of values compatible with the observed data under the method’s assumptions. It is not a guarantee that the true value lies in a particular interval, and it does not address biases arising from study design or data collection. The Wilson score method is one approach for constructing an interval around a percentage, particularly useful when working with a proportion rather than a continuous measurement.

The registry record does not report the primary percentages or confidence intervals. Thus, although the interval method is named, its numerical output cannot be assessed from the record. The posted safety counts do not substitute for the missing SVR12 estimate.

How was SVR12 defined?

SVR12 was based on hepatitis C virus RNA in the specified post-treatment window. The definition required RNA below the lower limit of quantification in that window and no confirmed quantifiable post-treatment result before or during it. The registry also describes rules for handling missing measurements. If a visit’s result was missing but the preceding and succeeding results were undetectable or unquantifiable, the missing result was imputed as undetectable or unquantifiable. If no value was available in the window after that step but a later RNA result existed, the later result was imputed into the window. A local laboratory result could also be used if the window still lacked a value. After these steps, participants still missing data were counted as failures.

These rules make the endpoint definition more explicit, but they also mean the reported percentage depends on the imputation procedure as well as observed measurements. Counting unresolved missing data as non-response is a conservative classification for the response endpoint, but it does not reveal why data were missing or how missingness might relate to outcomes. The registry record does not report how many participants required imputation or how many were ultimately classified as non-responders because of missing data.

Why does the design matter for interpretation?

General statistical principle: random allocation can help balance measured and unmeasured characteristics between treatment groups, supporting a more credible causal comparison. This study was non-randomized, and its parallel groups were organized around genotype and subtype. The regimens and treatment durations also differed across groups. Therefore, observed differences among groups could reflect differences in participants, genotype, regimen, duration, or other factors, rather than a treatment effect alone. The registry record explicitly cautions that the arms are not a like-for-like control comparison.

The study was open-label, meaning masking was absent. The registry does not describe how awareness of treatment assignment affected outcome assessment or reporting. SVR12 is defined using laboratory measurements, but the record does not provide further detail on safeguards against assessment or reporting bias.

What do planning illustrations mean?

General statistical principle: sample-size planning asks how many participants may be needed to detect a specified effect under stated assumptions. The registry record notes that any planning illustration is based on the observed effect, assumes a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect expressed as a fraction of the observed effect. Such figures are planning illustrations, not observed power and not results from the trial’s actual design. They should not be read as evidence that the study had a particular probability of detecting an effect. The registry does not report the trial’s own sample-size justification.

For binary outcomes such as a response percentage, a planning calculation depends on the assumed response rates, target difference, allocation, and chosen error and power criteria. General principle: changing the target effect or the assumptions can change the required sample size. No additional trial-specific planning assumptions or sample-size justification are reported in the registry record.

What statistical details remain unavailable?

The registry identifies the primary endpoint, its population, its timeframe, its confidence-interval method, and the missing-data rules. It also lists secondary outcomes. However, the record reports zero analyses, and the primary efficacy results are not reported in the registry record. Details such as any broader prespecified analysis plan, interim analyses, multiplicity procedure, and sensitivity analyses are not reported in the registry record. Without the result estimates and their uncertainty, the endpoint’s observed magnitude and precision cannot be evaluated.

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("Group 1: GT1B", "Group 2: GT1 Non-B")
n      <- c(9, 24)
events <- c(9, 23)
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  Group 1: GT1B  9  9  100.0  66.4  100.0  70.1  100.0  69.2  99.7
ARM  Group 2: GT1 Non-B  24  23  95.8  78.9  99.9  79.8  99.3  79.6  99.0

11. Multiplicity, Missing Data and Analysis Populations

The registry lists the primary SVR12 endpoint for Groups 1 and 2 and secondary outcomes that include SVR12 in Group 3, virologic failure, relapse, and changes in hepatic function tests, FibroTest, Child-Pugh score, and MELD score. It records eight outcome measures but zero analyses. The corresponding outcome results are not reported in the registry record.

When a study evaluates multiple outcomes, the chance of at least one apparently notable result can increase if each is assessed separately. General statistical principle: a multiplicity strategy can address this issue by controlling the interpretation of a family of tests or by identifying outcomes as exploratory. The registry record does not report a multiplicity adjustment or a hierarchy for interpreting the listed outcomes. It also does not report interim analyses or a broader statistical analysis plan.

The primary population is described as all participants who received at least 1 dose of study drug. The outcome description says missing data were addressed through flanking imputation, use of a later value or local laboratory value when applicable, and classification as failures when no value remained available. The record does not report the number of missing measurements, the number of participants affected by each imputation rule, or sensitivity analyses using alternative assumptions.

These omissions limit evaluation of how missing data and multiple outcomes may have influenced the results. Since the efficacy analyses themselves are not reported in the registry record, the extent to which these issues affected estimated endpoint values cannot be assessed.

12. 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: ascites (33.3%), diarrhoea (33.3%), general physical health deterioration (33.3%), hepatic failure (33.3%), hyperbilirubinaemia (33.3%).

The registry reports participants at risk and participants affected by serious and other adverse events for each group. Serious adverse events affected 1 of 9 participants in Group 1, 10 of 24 in Group 2, and 1 of 3 in Group 3. Other adverse events affected 8 of 9, 24 of 24, and 3 of 3, respectively. These are group-specific descriptive counts; they are not a randomized comparison of safety between regimens.

The registry’s listed serious adverse event terms are ascites, diarrhoea, general physical health deterioration, hepatic failure, hyperbilirubinaemia, and accidental overdose, each shown as 33.3%. The record does not report term-specific counts or clarify whether a participant could experience more than one listed term. The listed percentages therefore should not be interpreted as mutually exclusive categories or combined into a total.

The death counts are not reported in the registry record. The entries describe affected participants, not necessarily the total number of events or their duration, timing, severity beyond the serious classification, or relationship to study drug. The posted safety figures are useful as descriptive record entries, but the small and unequal group sizes and non-randomized design constrain comparative interpretation.

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

The record establishes that a Phase 3, open-label, non-randomized study evaluated genotype-specific antiviral regimens among adults with chronic hepatitis C and decompensated cirrhosis. It specifies the treatment groups, the primary SVR12 definition, the intended analysis population, and selected safety counts. These design and endpoint details help define what the study set out to examine.

The record does not report the primary SVR12 percentages or confidence intervals. It therefore does not establish what response rates were observed in Groups 1 and 2 or how precise those estimates were. The listed safety counts describe participants affected by events in each group, but do not support a causal comparison between the groups. Genotype, treatment regimen, treatment duration, and allocation all differ across arms.

General statistical principle: a treatment effect is best assessed through a design and analysis that support a fair comparison, alongside estimates and uncertainty. Descriptive outcomes from a non-randomized study may inform understanding of what was recorded in the enrolled groups, but cannot by themselves separate treatment effects from differences between groups. The registry record does not provide the efficacy results needed to assess even the descriptive SVR12 proportions.

Completion of the study is a status, not an efficacy conclusion. Likewise, safety counts do not establish whether a regimen is safe or unsafe in a broader population. The record leaves the primary efficacy result, the precision of that result, and several details about outcome analysis unavailable. Interpretation should stay within those limits.

14. Why This Trial Matters Statistically

This trial is statistically notable for the gap between a clearly specified primary endpoint and the absence of posted primary efficacy analyses. The registry defines SVR12, identifies the primary population, states the assessment timeframe, and names the Wilson score method for the confidence interval. Yet the record lists zero analyses, so neither the response percentages nor their uncertainty are available for interpretation.

The study also illustrates why study design is central to statistical interpretation. Although the trial had parallel groups, allocation was non-randomized and groups were based on genotype and subtype. Their treatment combinations and durations were not identical. Consequently, group differences cannot be treated as if they arose from a randomized comparison. The record itself cautions against treating the arms as like-for-like controls.

The safety record further illustrates how small and uneven groups constrain descriptive summaries. The at-risk counts range from 3 participants in Group 3 to 24 in Group 2. Adverse event counts can be reported for those enrolled, but this record does not make them precise comparative estimates or establish how representative they are of other populations.

Finally, the endpoint description shows that missing-data rules are part of the estimand’s practical interpretation: unresolved missing values were counted as failures after specified imputation steps. Without counts of missingness, outcome analyses, or sensitivity analyses, the influence of those rules cannot be assessed. The example highlights the importance of both reporting results and making the analysis decisions transparent.

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 central limitation for interpreting efficacy is that the registry record does not report the primary SVR12 results, confidence intervals, or analyses. The outcome definition is detailed, but the observed primary percentages and their precision are unavailable. The record also lists zero analyses, so the listed secondary outcomes cannot be evaluated from reported results.

The design limits comparisons across groups. Allocation was non-randomized, participants were grouped by genotype, and treatment combinations or durations differed. The trial therefore does not provide a randomized comparison among the three regimens. The record does not report adjustment methods that might address differences among participants or other potential sources of confounding.

Group sizes are limited and uneven. The registry lists 9 participants at risk for serious and other adverse events in Group 1, 24 in Group 2, and 3 in Group 3. In particular, safety descriptions for Group 3 reflect a small number of participants and should not be treated as precise estimates for a wider population.

Safety reporting is also incomplete for some interpretive purposes. Death counts are not reported in the registry record, and the listed serious event terms lack term-specific counts. The record does not clarify whether participants could have multiple listed terms or provide further timing and attribution details. It does not report the number of participants with missing endpoint data or sensitivity analyses of the imputation rules.

The registry does not report the trial’s sample-size justification, a broader statistical analysis plan, interim analyses, or a multiplicity procedure. These unreported details limit assessment of how design and analysis choices were planned and applied.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study to Evaluate the Safety and Efficacy of Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir With Ribavirin in Adults With Genotype 1 and Ombitasvir/Paritaprevir/Ritonavir With Ribavirin in Adults With Genotype 4 Chronic Hepatitis C Virus Infection and Decompensated Cirrhosis — NCT02219477.
• Registry record last updated 2017-07-11; status last verified 2017-06.
• Results first posted 2017-07-11.
• 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

TURQUOISE-CPB was a completed Phase 3, open-label, non-randomized, parallel-group study sponsored by AbbVie, with an enrollment of 36. It evaluated genotype-specific antiviral regimens in adults with chronic hepatitis C virus infection and decompensated cirrhosis. Group 1 had genotype 1b infection, Group 2 genotype 1 non-B infection, and Group 3 genotype 4 infection.

The primary endpoint was SVR12 in Groups 1 and 2, assessed 12 weeks after the last actual dose. The registry defines the endpoint and the missing-data approach, and specifies the Wilson score method for its 95% confidence interval. It lists safety counts and several secondary outcomes. However, primary efficacy results are not reported in the registry record, which lists zero analyses. The design does not support a like-for-like comparison between the groups.