A Study to Evaluate Chronic Hepatitis C Infection in Adult Transplant Recipients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Evaluate Chronic Hepatitis C Infection in Adult Transplant Recipients (NCT01782495), a non-randomized phase 2 study. The primary outcome is Percentage of Participants With Sustained Virologic Response 12 Weeks Post-treatment (SVR12).

2. Clinical Question

The study’s stated purpose was to evaluate safety and efficacy of the regimens in adult transplant recipients with HCV genotype 1 or 4 infection. Its design organized treatment by transplant type, viral genotype, cirrhosis status, and, for some arms, prior treatment history. That structure matters when interpreting results: participants receiving different regimens were not necessarily comparable in the characteristics that determined their treatment group.

The record identifies secondary outcomes as SVR24, on-treatment virologic failure, and post-treatment relapse. It does not provide numerical results for these outcomes in the registry record described. The primary question can therefore be stated, but the posted information does not support a numerical answer about how often participants achieved SVR12 or how precisely that percentage was estimated.

3. Trial Design

This was a completed Phase 2 study with non-randomized allocation, no masking, and a parallel model. The registry record lists enrollment as 129. The study began on 2013-02-25 and reached primary completion on 2016-11-02. AbbVie is listed as sponsor. These design details describe how the trial was organized; they do not establish a comparative treatment effect.

The parallel arms differed in several ways. Arms A through G enrolled liver transplant recipients with genotype 1 infection, with distinctions by genotype subtype, cirrhosis status, prior treatment experience, ribavirin use, and treatment duration. Arms H and I enrolled renal transplant recipients with genotype 1 infection without cirrhosis. Arms J and K enrolled liver transplant recipients with genotype 4 infection, respectively without cirrhosis and with Child Pugh A cirrhosis. The arm descriptions specify regimens and durations of 12 or 24 weeks.

For genotype 1, the regimens combined ombitasvir/paritaprevir/ritonavir with dasabuvir; some included weight-based ribavirin and some did not. The genotype 4 arm descriptions list ombitasvir/paritaprevir/ritonavir with weight-based ribavirin. The record’s description of Arm B is truncated, so its full regimen details are not reported in the registry record.

Because allocation was non-randomized, arm membership reflected characteristics and treatment histories that varied across the study groups. An observed difference between arms could reflect those differences, the regimen, or other factors. Open-label conduct also means masking was absent, although the record does not describe how that may have affected individual outcome assessments. A protocol-level account of allocation procedures, sample-size justification, interim analyses, and the prespecified statistical plan is 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.

Before assignment: This study included a 35-day screening period.

Only the first 6 of 11 groups are shown.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Intent-to-treat (ITT) population: All participants who received at least 1 dose of study drug.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Only the first 6 of 12 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants With Sustained Virologic Response 12 Weeks Post-treatment (SVR12), measured over 12 weeks after the last actual dose of study drug.

The primary endpoint was the percentage of participants with sustained virologic response 12 weeks after the last actual dose of study drug, termed SVR12. The registry defines response as plasma HCV RNA below the lower limit of quantification at that follow-up. Participants with missing data after backward imputation were classified as nonresponders. The analysis population is described as the intent-to-treat population: all participants who received at least one dose of study drug.

SVR12 is a binary outcome at a specified follow-up point: each participant is classified as meeting or not meeting the response definition under the registry’s missing-data rule. Reporting the percentage conveys how common the defined response was in the analyzed group. A confidence interval communicates uncertainty around that estimated percentage; it helps readers distinguish a relatively precise estimate from one that is compatible with a broader range of underlying values.

The registry lists a 95% confidence interval as the dispersion measure for the primary endpoint, but its numerical estimate and interval are not reported in the registry record. The endpoint definition alone does not reveal how many participants met the criterion. The record also lists SVR24, on-treatment virologic failure, and post-treatment relapse as secondary outcomes, without numerical results in the registry record described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a binary response outcome summarized as a percentage. Each participant is classified according to whether the HCV RNA criterion was met at the specified follow-up. A percentage is a descriptive estimate of the share of the analysis population meeting that definition. The registry lists a 95% confidence interval as its measure of dispersion. In general, a confidence interval expresses the uncertainty associated with an estimate under the statistical method used; it is not a guarantee that the true value lies within the particular interval.

The registry identifies the primary population as intent-to-treat, defined in this record as all participants who received at least one dose of study drug. It also specifies that missing data after backward imputation were treated as nonresponse. This rule makes missing outcomes count against response in the endpoint classification, rather than silently omitting those observations. However, the description does not explain how often data were missing, how backward imputation was implemented, or whether other sensitivity analyses were conducted. Those details are not reported in the registry record.

In general, binary-outcome estimates depend on both the number classified as responding and the denominator used. A confidence interval is wider when the data provide less information and narrower when they provide more information, subject to the method and the observed result. Here, neither the primary endpoint counts nor its numerical estimate and interval are reported. It is therefore not possible to assess the observed response percentage, its precision, or whether the estimate varied across arms using the registry entries described.

What does non-randomized allocation change?

Random allocation is commonly used to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics. This study is explicitly non-randomized. Its arms were defined by patient and disease characteristics, including transplant type, HCV genotype, cirrhosis status, and treatment history. Those features may also be related to outcomes. As a general principle, differences between such groups can reflect differences in who entered each group as well as differences between regimens.

That issue is distinct from statistical precision. A narrow confidence interval, if one had been reported, would describe uncertainty under its model but would not by itself remove bias from non-random group assignment. Conversely, a broad interval would indicate imprecision, not necessarily bias. The record does not report a statistical adjustment strategy or sufficient numerical outcome information to evaluate adjusted or unadjusted treatment contrasts.

How should the confidence interval be read?

The registry specifies a 95% confidence interval for the primary percentage. In general, confidence intervals help communicate how compatible the observed data are with a range of values under the method’s assumptions. They are more informative than a point estimate alone because they show the degree of sampling uncertainty. Their interpretation depends on the analysis and the data, and they do not account automatically for selection bias, outcome misclassification, or differences between non-randomized groups.

The interval itself is not reported in the registry record. No numerical claim about its width, the underlying response percentage, or evidence for a difference between arms can be made. The presence of a stated interval type is a description of the intended reporting metric, not evidence that an estimate was posted.

What can the safety counts describe?

The adverse-event record lists arm-specific counts at risk and affected for serious and other adverse-event categories, along with deaths. These are descriptive safety summaries. In general, counts and percentages can describe the observed experience in a group, but comparisons require attention to the denominators, follow-up, definitions, and differences among groups. Because the design is non-randomized and group composition varies, raw arm-level counts do not establish that a regimen caused an event or that one regimen is safer than another.

Some adverse-event risk sets are small, as reflected in the arm-specific counts. With limited observations, estimates of event frequency can be unstable, and an event not recorded in a group does not prove that its underlying risk is absent. The record does not report detailed event-specific follow-up, exposure-adjusted analyses, or statistical comparisons for safety. These general considerations apply to interpretation; they are not additional findings from the trial.

What analysis details remain unclear?

The registry record does not report the sample-size justification, a detailed statistical analysis plan, planned handling of multiplicity, interim analyses, or methods for adjusted comparisons. The listed secondary endpoints indicate that more than one outcome was of interest, but the registry entries do not establish a testing hierarchy or correction procedure. In general, evaluating multiple outcomes or comparisons can increase the chance of a chance-positive finding if each is treated as a separate confirmatory test. Without the prespecified approach and numerical results, the strength of any inferential claims cannot be evaluated from the record.

The registry entries also do not describe whether analyses were conducted separately for each arm or pooled across selected groups, or how any protocol deviations were handled. These omissions limit reconstruction of the analysis. The statistical interpretation should remain tied to what the record explicitly describes: an ITT definition, a missing-data rule, a binary primary endpoint, and a stated confidence-interval type, without numerical primary efficacy estimates.

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("Arm A", "Arm B", "Arm C", "Arm D", "Arm E", "Arm F")
n      <- c(34, 27, 13, 4, 2, 22)
events <- c(33, 26, 13, 4, 2, 21)
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  Arm A  34  33  97.1  84.7  99.9  85.1  99.5  85.1  99.3
ARM  Arm B  27  26  96.3  81.0  99.9  81.7  99.3  81.7  99.1
ARM  Arm C  13  13  100.0  75.3  100.0  77.2  100.0  76.8  99.8
ARM  Arm D  4  4  100.0  39.8  100.0  51.0  100.0  47.8  99.5
ARM  Arm E  2  2  100.0  15.8  100.0  34.2  100.0  29.2  99.2
ARM  Arm F  22  21  95.5  77.2  99.9  78.2  99.2  78.1  98.9

11. Multiplicity, Missing Data and Analysis Populations

The primary endpoint’s analysis population is defined as all participants who received at least one dose of study drug. The record states that participants with missing data after backward imputation were classified as nonresponders. This definition and rule clarify how the endpoint was intended to be interpreted, but the registry does not report the number of missing outcomes, the details of the imputation procedure, or results under alternative missing-data assumptions. Those details are not reported in the registry record.

The registry lists SVR24, on-treatment virologic failure, and post-treatment relapse as secondary outcomes. It does not describe a hierarchy among the primary and secondary outcomes, a family-wise error approach, or another adjustment for multiple testing. The multiplicity plan is not reported in the registry record. In general, when several outcomes or comparisons are tested, the chance of at least one chance finding can rise unless the analysis plan accounts for the number and role of the tests. This is a general statistical concern, not evidence that a particular result in this study is a chance finding.

Although the registry entries identify an intent-to-treat population and an endpoint-specific missing-data rule, they do not describe additional analysis populations, sensitivity analyses, or handling of protocol deviations. The numerical primary and secondary outcome results are also not reported in the registry record. As a result, neither the influence of missing data nor the role of multiplicity in the reported conclusions can be evaluated 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: nausea (11.1%), vomiting (11.1%), atypical pneumonia (11.1%), overdose (11.1%), ischaemic cerebral infarction (11.1%).

The registry lists serious adverse-event counts by arm as affected participants among those at risk. The recorded at-risk and affected counts are: Arm A, 34 and 2; Arm B, 27 and 1; Arm C, 13 and 0; Arm D, 4 and 0; Arm E, 2 and 0; Arm F, 22 and 2; Arm G, 12 and 1; Arm H, 9 and 4; Arm I, 3 and 0; Arm J, 2 and 0; and Arm K, 1 and 0. These are descriptive counts, not adjusted comparisons between regimens.

The registry lists other adverse-event counts as affected among those at risk: Arm A, 34 and 33; Arm B, 27 and 27; Arm C, 13 and 12; Arm D, 4 and 4; Arm E, 2 and 2; Arm F, 22 and 22; Arm G, 12 and 12; Arm H, 9 and 8; Arm I, 3 and 3; Arm J, 2 and 2; and Arm K, 1 and 1. One death is recorded in Arm H, and no deaths are recorded in the other listed arms.

The record names nausea, vomiting, atypical pneumonia, overdose, ischaemic cerebral infarction, and acute kidney injury among the top serious terms, each at 11.1%. The denominator for these term percentages is not reported in the registry record. Event counts and percentages describe what was recorded; by themselves they do not establish causation or permit a like-for-like safety comparison across these non-randomized groups.

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

The registry record identifies the trial population, regimens, design, and primary endpoint definition. It also specifies that missing primary endpoint data after backward imputation were classified as nonresponse and that the primary analysis population included participants who received at least one dose. These details clarify the intended meaning of an SVR12 result.

The record does not report the numerical SVR12 outcome or its 95% confidence interval. It therefore does not show the observed percentage meeting the endpoint or how precisely that percentage was estimated. The listed secondary endpoints also lack numerical results in the registry record described. The study’s outcome cannot be characterized from endpoint definitions alone.

Even if arm-level efficacy estimates were available, the non-randomized design would make direct causal comparisons difficult. The groups differed by characteristics that determined arm assignment, including genotype, transplant type, cirrhosis status, and treatment history. An arm-level difference could not automatically be attributed to its regimen. The record does not describe an adjustment method that would resolve these concerns.

The safety counts give descriptive information about adverse events recorded in each arm, but they are not proof that a regimen caused or prevented an event. Group composition and the reported at-risk counts vary, and the record does not provide detailed safety comparisons or exposure-adjusted analyses. The recorded death in Arm H is a descriptive entry, not by itself evidence about the cause of death or a comparative risk.

These limits do not negate the value of a registry record. They define what can be concluded from it. The record documents a Phase 2 study of several regimens in transplant recipients with genotype 1 or 4 infection, but its the registry entries do not supply the primary numerical efficacy result needed to judge the observed SVR12 estimate. No treatment recommendation or conclusion about an individual’s care follows from these data.

14. Why This Trial Matters Statistically

This trial illustrates why endpoint definitions and numerical results must be read together. The registry gives a specific SVR12 criterion, follow-up timing, analysis population, and missing-data rule. Those elements make clear what the primary percentage is meant to represent. Yet without the result and confidence interval, the endpoint’s observed frequency and precision remain unknown.

Its non-randomized, multi-arm structure also highlights the difference between describing groups and estimating a treatment effect. Arm eligibility varied with transplant type, HCV genotype, cirrhosis status, and treatment history, while regimens and durations varied across arms. In general, such differences complicate direct comparisons because the groups may differ in factors that also relate to outcomes. Statistical adjustment can sometimes address measured differences, but the registry entries do not describe an adjustment strategy.

The study therefore offers a useful statistical reading exercise: distinguish the treatment question from the available evidence, separate descriptive safety counts from causal comparisons, and identify missing reporting that prevents assessment of precision. The listed confidence-interval type does not substitute for the interval itself, and a trial’s completion status does not reveal its outcome.

For researchers and clinicians reading registry records, the key lesson is to track what is explicitly reported and what remains unknown. Here, the design and endpoint are described, while the numerical primary efficacy result, secondary outcome results, multiplicity approach, and detailed statistical plan are not reported in the registry record. Keeping those distinctions visible prevents an incomplete record from being mistaken for a complete efficacy analysis.

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 most direct limitation of the posted record is the absence of numerical primary efficacy results. The SVR12 percentage and its 95% confidence interval are not reported in the registry record, and numerical results for the listed secondary outcomes are not reported in the registry record described. The primary endpoint can be defined, but its observed value and precision cannot be assessed.

The study was non-randomized and open-label. Its arms represent different combinations of patient characteristics and treatment regimens rather than randomized groups. Genotype, transplant type, cirrhosis status, treatment history, ribavirin use, and treatment duration varied across the arm descriptions. These features constrain causal interpretation and make direct arm-to-arm comparisons potentially confounded.

There is variation in the arm-specific safety at-risk counts, including groups with few observations. That makes raw event counts difficult to compare and can limit the stability of any group-specific frequency estimate. The registry entries do not provide primary efficacy denominators by arm, detailed follow-up for adverse events, or exposure-adjusted safety estimates. The denominator for the listed serious-event term percentages is not reported in the registry record.

Important analysis details are also not reported in the registry record: the sample-size justification, a detailed statistical analysis plan, planned multiplicity handling, interim analyses, additional analysis populations, and sensitivity analyses for missing data. The Arm B description is truncated, leaving its full regimen description unreported in the registry record. These gaps limit both reconstruction of the study methods and assessment of the robustness of its results.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study to Evaluate Chronic Hepatitis C Infection in Adult Transplant Recipients — NCT01782495.
• Registry record last updated 2017-11-07; status last verified 2017-10.
• Results first posted 2017-11-07.
• 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

NCT01782495 is a completed, open-label, non-randomized Phase 2 study of regimens for adult liver or renal transplant recipients with chronic HCV genotype 1 or 4 infection. The record lists enrollment as 129 and describes parallel arms that vary by transplant type, genotype, cirrhosis status, treatment history, regimen, and duration.

The primary endpoint is SVR12, defined as HCV RNA below the lower limit of quantification 12 weeks after the last actual dose. The primary population is participants who received at least one dose, with missing data after backward imputation classified as nonresponse. The registry record does not report the numerical primary result or confidence interval. It also lists SVR24, on-treatment virologic failure, and post-treatment relapse as secondary outcomes without numerical results in the registry record described.

Arm-level adverse-event counts and deaths are recorded, but the non-randomized design does not support simple causal comparisons across arms. The statistical plan, sample-size justification, and multiplicity approach are not reported in the registry record.