Study to Evaluate the Safety and Efficacy of Daclatasvir/Sofosbuvir/Ribavirin for 16 Versus 24 Weeks for HCV Genotype 3 Cirrhotics: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Evaluate the Safety and Efficacy of Daclatasvir/Sofosbuvir/Ribavirin for 16 Versus 24 Weeks for HCV Genotype 3 Cirrhotics (NCT02304159), a randomized phase 4 study. The primary outcome is Number of Participants With Adverse Events.

2. Clinical Question

The record describes a randomized, open-label, single-center study in cirrhotic participants with chronic hepatitis C genotype 3. It compares treatment duration while listing the same combination of medicines in both groups. The title and summary refer to safety and efficacy, but the primary outcome is the number of participants with adverse events.

The posted counts are 21 participants with adverse events among 21 in the 16-week group and 18 among 18 in the 24-week group. Thus, the primary endpoint is at its maximum observed count in both groups: every participant represented in each group is counted as having had an adverse event. This outcome does not convey the event types, number of events per participant, severity of non-serious events, or their timing. Those details are not reported in the registry record for this primary outcome.

The comparison is therefore narrowly framed. It describes whether participants had an adverse event during treatment, not how often events happened, how burdensome they were, or whether one duration produced a different clinical outcome. The posted equality in counts is descriptive evidence for this endpoint in this trial, and should be read alongside the trial's size, its reporting limitations, and the separate serious-event information.

3. Trial Design

This is a randomized, parallel-group, open-label, single-center study listed as phase 4. Participants were allocated to one of two treatment durations: Group A received the combination for 16 weeks, and Group B received it for 24 weeks. The record identifies 39 enrolled participants; the posted group sizes are 21 and 18. The registry summary had described a plan to enroll at least 40 participants, and the reason the recorded enrollment differs from that stated target is not reported in the registry record.

Both groups received daclatasvir, sofosbuvir and ribavirin. The arm descriptions specify sofosbuvir 400 mg daily, ribavirin 1000-1200 mg daily based on weight, and daclatasvir 60 mg daily. The assigned duration is the stated contrast between groups. There is no untreated or placebo group described in the record.

The study was unmasked, so participants and study staff were not blinded to the treatment duration. The record says that participants would return to the study center at various points during treatment and at 12 weeks after their last study-drug dose to monitor safety and efficacy, with visits according to standard of care. Specific visit dates and detailed assessment procedures are not reported in the registry record.

The primary outcome is the number of participants with adverse events from baseline, defined in the timeframe as the start of study drugs, through the last day of taking study drugs. The timeframe is described as an average of 20 weeks. The registry record also lists 3 outcome measures, but no secondary results are posted. The analysis population, handling of participants who stopped treatment or missed visits, and detailed statistical analysis plan are not reported in the registry record.

The registry record lists a completed study, with start and primary completion recorded as 2015-01 and 2017-08. Completion status alone does not describe whether every planned assessment was obtained or whether the analysis followed an intended protocol. Those details are not reported in the registry record.

4. Participant Flow and Accounting

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

Overall Study

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.

Population: A total of 39 participants started treatment with sofosbuvir, ribavirin and daclatasvir. 21 were randomized to Group A (16 weeks of treatment). 18 were randomized to Group B (24 weeks of treatment).

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Adverse Events, measured over From baseline (start of study drugs) to last day of taking study drugs; an average of 20 weeks..

The primary endpoint counts participants who had an adverse event during the defined treatment period. Its timeframe begins at the start of study drugs and ends on the last day of treatment; the registry describes this as an average of 20 weeks. The outcome is expressed as a count of participants, rather than as the total number of events. A participant with more than one event still contributes one participant to this particular count.

Counting participants with at least one adverse event is a common way to summarize whether any event was experienced during a specified period. As a general statistical explanation, a binary endpoint reduces each participant's experience to one of two categories: event recorded or no event recorded. This makes group counts easy to compare, but it does not retain information about event frequency, duration, severity, or clinical context. Those aspects require separate reporting.

In this record, the displayed counts are 21 of 21 in the 16-week group and 18 of 18 in the 24-week group. Both groups therefore have all participants represented in the event category for the primary outcome. These data do not describe what kinds of non-serious events were included, whether events were judged related to study treatment, or how events were defined and collected. Such endpoint details are not reported in the registry record.

The outcome is a safety measure, while the study title and summary also refer to efficacy. No efficacy finding should be inferred from this primary safety count. The registry record does not report a primary viral-response measure in the results. The distinction matters: a count of participants with any adverse event cannot by itself answer a question about treatment efficacy, and it cannot summarize the full clinical importance of safety events.

7. Results Posted in the Registry

• Group B - 24 Weeks: 100.0% (18/18) versus 100.0% (21/21) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

What is being compared?

The study uses a randomized, parallel-group design. Participants were assigned to the same three-drug regimen for either 16 weeks or 24 weeks. Random allocation is intended, in general, to make groups comparable at the point of assignment by distributing measured and unmeasured characteristics without systematic selection. It does not guarantee that the groups will be identical, particularly in a study with 39 enrolled participants. The allocation sequence and procedures for concealment are not reported in the registry record.

The study is open label, meaning the assigned duration was not masked from participants and investigators. For an outcome such as any adverse event, knowledge of treatment assignment can potentially affect reporting, observation, or recording. This is a general design consideration, not evidence that reporting differed in this study. The record does not describe procedures to standardize or independently assess adverse-event collection.

How should a binary outcome be read?

The primary outcome is a count of participants who experienced at least one adverse event during treatment. Statistically, this can be represented as a binary outcome for each participant: an event was recorded, or it was not. The registry gives counts and group sizes, and also reports a risk difference comparing the groups. A risk difference expresses the difference between the group proportions with the event. Here, the posted group proportions are both 1.0, and the posted risk difference is 0.0.

As a general explanation, a risk difference is an absolute comparison on the probability scale. It does not describe the number of separate events, and it can be uninformative about event type or severity when all participants fall into the same outcome category. Other measures could be used for binary outcomes, but the registry's posted comparison is the risk difference. The record does not report whether any adjusted or alternative analyses were conducted.

What does the confidence interval contribute?

A confidence interval is a range of values generated by a statistical procedure to express uncertainty around an estimate. In general, its width depends on the amount of information in the data and the method used to construct it. The record displays an interval from 0.0 to 0.0 for the risk difference. The method used to derive that interval is not reported in the registry record, so readers cannot assess its assumptions or reproduce it from the record alone. Its displayed width should not be taken as proof that there is no uncertainty about the underlying difference.

The sample-size assumptions described for planning illustrations are not a documented rationale for this trial's enrollment. The registry record does not report the trial's own sample-size justification, target effect, or design assumptions. Any sample-size illustrations elsewhere on the page are planning calculations based on the observed effect, not observed power and not a replacement for the study's original design rationale.

What does the p-value mean?

The posted comparison gives p=1.0. In general, a p-value is calculated under a specified statistical model and summarizes how unusual the observed data, or data more extreme, would be if a null hypothesis were true. It is not the probability that the null hypothesis is true, and it does not establish equivalence or clinical importance. Interpreting a p-value requires knowing the analysis method and assumptions. Those methods are not reported in the registry record.

The exact equality in the posted counts is directly visible without relying on a p-value. The p-value does not add information about the kinds of adverse events, nor does it resolve limitations in endpoint definition and event reporting. Since the record does not describe a prespecified statistical plan, the status of this comparison as prespecified or exploratory is not reported in the registry record.

What analysis details are unavailable?

The registry record does not report an analysis population, such as whether the primary comparison included everyone randomized or only those who completed treatment. It does not report how missing outcome data, treatment discontinuations, or deviations from assigned duration were handled. These details matter in general because missing or excluded observations can change the composition of the groups being compared. The posted group sizes are 21 and 18, but their relationship to all randomized participants and to the analysis population is not described.

The record gives no detailed model specification, covariate adjustment, method for confidence-interval construction, or explanation of the p-value calculation. It also does not describe interim analyses or a multiplicity strategy. No such procedure should be inferred from the existence of posted numerical comparisons.

The primary outcome is binary, but safety data can also be summarized using event counts, event rates, severity categories, or time-to-event methods. These approaches answer different questions. The primary outcome counts participants with an event and does not summarize repeated events. No rate calculation or time-to-event comparison is reported in the registry record.

Finally, three outcome measures are listed in the record, while no secondary results are posted. The record therefore does not support conclusions about secondary endpoints or about a broader efficacy analysis. These methodological limits do not erase the reported counts; they define how narrowly those counts should be interpreted.

10. Confidence Intervals and Precision

The primary result is based on 21 participants in the 16-week group and 18 in the 24-week group. Every participant in both groups is counted as having had an adverse event. The comparison reports a risk difference of 0.0 and a confidence interval from 0.0 to 0.0. The p-value is 1.0.

A confidence interval is generally intended to show the range of effect values compatible with the data under a specified method. Its interpretation depends on how it was calculated and on the assumptions used. The registry record does not identify the interval method. For that reason, the displayed zero-width interval should be quoted as the registry's result, but not treated as a complete account of uncertainty or as evidence that the true difference must be exactly zero.

With all participants counted as having an event, the binary outcome has no observed contrast in event status between groups. However, a result with no observed contrast does not establish that the groups have identical underlying safety experience. The outcome is coarse, the group sizes are limited, and the record does not provide detailed information about event types or severity. It also does not report how the interval was produced or whether other analyses were performed.

Precision is not only a property of an interval. It also concerns how well the endpoint captures the question of interest. A count of participants with any adverse event may be precise as a count while remaining limited as a summary of safety. It cannot distinguish one event from multiple events or mild events from serious ones. Separate serious-event counts are posted, but they do not provide a complete event-level account.

Any planning illustrations elsewhere on the page should be understood as illustrations based on the observed effect, not as evidence of the trial's actual power. The trial's original sample-size justification is not reported in the registry record. The posted numbers therefore support a narrow description of observed counts, while the wider uncertainty about differences in underlying safety outcomes remains incompletely characterized.

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists 3 outcome measures, but no secondary results are posted. The result is the primary outcome: the number of participants with adverse events during treatment. The record does not provide a full list of secondary outcome findings or indicate how any additional outcomes were analyzed.

Multiplicity is the issue that arises when several outcomes, comparisons, or analyses are examined. As a general statistical explanation, testing many questions can increase the chance of finding at least one result that appears notable by chance. Researchers may address this through a prespecified hierarchy, adjustment, or another plan. Whether any such strategy was used in this study is not reported in the registry record. It is also not reported whether there were interim analyses or other planned comparisons.

The registry comparison reports a p-value for the primary safety endpoint, but the analysis plan and the status of the comparison as prespecified are not documented. The result should not be treated as a comprehensive statistical account of all trial outcomes. No efficacy result can be inferred from the adverse-event count.

Missing-data procedures and analysis populations are also not reported in the registry record. The record gives group sizes of 21 and 18 for the primary result, but does not say whether these represent all randomized participants, all treated participants, or another analysis set. It does not state how participants with incomplete follow-up, early treatment cessation, or unavailable adverse-event information were handled.

In general, missingness can matter if the likelihood of missing data is related to treatment or to a participant's outcome. Without information on missing observations and their handling, readers cannot assess that possibility. The record also does not report sensitivity analyses examining alternate assumptions about missing data. These omissions limit assessment of robustness; they do not change the fact that the posted counts are 21 of 21 and 18 of 18.

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: infection (5.6%), violence (5.6%).

The serious adverse-event summary lists 0 participants with serious events among 21 at risk in the 16-week group and 2 among 18 at risk in the group associated with the 24-week duration. It also lists 1 death in each group. These counts are separate from the primary endpoint, which counts any adverse event, whether serious or not.

The safety grouping labels contain an inconsistency: the group with 18 participants is labelled “Group A - 24 Weeks of Treatment,” while the randomized-arm descriptions identify the 24-week group as Group B. The counts align with the group size of 18, but the label is not consistent. This should be kept in mind when reading the safety summary; the reason for the discrepancy is not reported in the registry record.

The record lists Infection and Violence among the top serious-event terms, each shown as 5.6%. It does not provide further context about event definitions, timing, seriousness criteria, attribution to study drugs, or whether the listed terms represent unique participants or events. The relationship of either death to treatment is not reported in the registry record.

These figures are counts from a small study, not a complete comparison of all potential safety risks. They describe what is posted and do not establish why the events occurred or whether treatment duration caused them.

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

The result shows that the primary adverse-event count was the same in both randomized groups at the level of event presence: every participant in the 16-week group and every participant in the 24-week group was counted as having experienced an adverse event during treatment. The posted risk difference is 0.0, with a reported interval of 0.0 to 0.0 and p=1.0. This is a statement about the registry's binary primary endpoint, not an overall judgment about the safety of either regimen.

It does not mean that the event experiences were identical. The primary outcome does not show whether participants had one event or several, which event types occurred, or whether the groups differed in severity, duration, or consequences. The separate serious-event summary lists 0 serious events among 21 participants in the 16-week group and 2 among 18 in the group associated with 24 weeks, as well as 1 death in each group. The registry record does not report the deaths' relationship to treatment.

Nor does this primary result show whether the treatment durations have equal effects on hepatitis C. The endpoint is a safety count; the posted information does not provide an efficacy result. The title and summary refer to efficacy, but that wording should not be substituted for posted outcome data.

As a general statistical point, a lack of observed difference is not the same as proof of equivalence. Equivalence or non-inferiority claims require an appropriate design, prespecified margins, and analysis details. These are not reported in the registry record. The displayed confidence interval is also not accompanied by its calculation method, so it cannot resolve that limitation.

The trial therefore contributes a limited descriptive observation about any adverse event in these participants during treatment, alongside sparse serious-event counts. It does not establish that changing treatment duration has no effect on all safety outcomes, does not resolve efficacy, and does not explain the cause or treatment relationship of individual events. The modest enrollment and incomplete methodological reporting call for a narrow reading of the result.

14. Why This Trial Matters Statistically

This trial is statistically notable because its primary binary safety outcome is recorded for every participant in both groups: 21 of 21 in the 16-week group and 18 of 18 in the 24-week group had an adverse event. The comparison therefore has no observed difference in whether an event occurred. That pattern makes clear why a single binary summary can be useful for a simple group comparison while still leaving important safety questions unanswered.

When every participant falls into the event category, this endpoint cannot distinguish groups by event presence. It also cannot reflect the number of events per person or their seriousness. The separately posted serious-event information illustrates why different outcome summaries matter: serious events and any adverse event are not interchangeable endpoints. The record provides counts for both, but limited context for interpreting either.

The result also highlights the importance of transparent statistical reporting. The record displays a zero risk difference, a zero-to-zero confidence interval, and p=1.0, but does not report the interval method, p-value method, analysis population, or missing-data procedures. Without those details, readers can describe the posted result but cannot fully assess its inferential basis or robustness.

Finally, the safety grouping label for the 18-participant group does not match the randomized-arm naming in the trial description. This small but concrete reporting inconsistency is a reminder that labels and denominators need to be checked alongside numerical results. Taken together, the trial offers a focused example of the difference between a reported estimate and the broader evidence needed to interpret it: outcome definition, analysis methods, event detail, and transparent accounting all shape what a statistical result can mean.

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 registry record describes a single-center, open-label randomized study with 39 enrolled participants. The posted groups contain 21 and 18 participants. This is a limited amount of information for characterizing uncommon or varied safety outcomes, and the record does not report a trial-specific sample-size justification. The brief summary says at least 40 participants would be enrolled, while the recorded enrollment is 39; the reason for this difference is not reported in the registry record.

The primary endpoint is a broad count of participants with any adverse event. Since all participants in both groups are counted as having an event, this result cannot describe differences in event burden or event severity. The registry record does not provide the primary endpoint's detailed event definition, the method of event collection, or the relationship of events to treatment.

The study was open label, and the record does not explain how adverse-event reporting or assessment was standardized. It does not report an analysis population, missing-data handling, treatment discontinuations, protocol deviations, interim analyses, or a full statistical plan. The method behind the posted confidence interval and p-value is also not reported in the registry record.

Serious-event reporting has limited detail and includes a mismatch in the group label for the 18-participant group. The record lists 2 participants with serious events in that group, 0 in the other group, and 1 death in each; timing, cause, and relationship to treatment are not stated. The efficacy references in the study title and summary are not accompanied by a posted efficacy finding in the material. These limitations restrict interpretation to the reported counts and prevent broader conclusions about comparative safety or efficacy.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study to Evaluate the Safety and Efficacy of Daclatasvir/Sofosbuvir/Ribavirin for 16 Versus 24 Weeks for HCV Genotype 3 Cirrhotics — NCT02304159.
• Registry record last updated 2019-04-24; status last verified 2019-04.
• Results first posted 2019-04-24.
• 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

The registry record describes a completed, randomized, open-label, parallel-group, single-center phase 4 study comparing 16 and 24 weeks of daclatasvir, sofosbuvir and ribavirin in cirrhotic participants with chronic hepatitis C genotype 3. It records 39 enrolled participants, with group sizes of 21 and 18.

The primary outcome counts participants with adverse events from the start of study drugs through the last day of treatment, described as an average of 20 weeks. The posted counts are 21 of 21 in the 16-week group and 18 of 18 in the 24-week group. The registry reports a risk difference of 0.0, an interval from 0.0 to 0.0, and p=1.0.

The serious-event summary lists 0 participants among 21 in one group and 2 among 18 in the group associated with 24 weeks, with 1 death in each group. A safety label for the 18-participant group conflicts with the randomized-arm naming. The record does not report detailed analysis methods, missing-data handling, the interval method, or a posted secondary result.