This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Study to Treat Subjects With Telaprevir, Ribavirin, and Peginterferon Who Are Coinfected With HIV and Hepatitis C Virus (HCV) (NCT01467479), a non-randomized phase 3 study. The primary outcome is Percentage of Participants With Sustained Viral Response 12 Weeks After Last Planned Dose of Study Drug (SVR12).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01467479 |
| Phase | Phase 3 |
| Condition | Hepatitis C |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 185 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Vertex Pharmaceuticals Incorporated |
| Results posted | Yes |
2. Clinical Question
The study asked whether treatment with telaprevir, pegylated interferon alfa 2a, and ribavirin could be followed by an undetectable HCV RNA result 12 weeks after the last planned dose of study drug among people coinfected with HIV and HCV. The registry specifies genotype 1 HCV and HIV-1 in the official title. It describes SVR12 as the primary outcome, with measurement scheduled 12 weeks after the last planned dose, up to Week 60.
Population
People coinfected with genotype 1 HCV and HIV-1. For the primary outcome, the registry defines the Safety Set as participants who received at least 1 dose of study drug; the number evaluable varies by category and arm.
Intervention
Telaprevir in combination with pegylated interferon alfa 2a and ribavirin. Participants were also receiving HAART, with the listed regimen groups based on ATV/r, EFV, or RAL at baseline.
Comparator
There was no randomized control group. The registry lists HAART-based regimen groups, but allocation was non-randomized, so these groups are not a like-for-like control comparison.
Primary question
What percentage of evaluable participants had undetectable HCV RNA 12 weeks after their last planned dose of study drug?
This is a question about a defined virologic outcome after treatment, not a direct randomized comparison of the study regimen against another treatment. The registry also lists secondary outcomes covering SVR24, early viral responses, end-of-treatment HCV RNA, adverse events, drug concentrations, and telaprevir-resistant HCV variants. The record does not report the primary outcome result, so it does not establish the observed proportion reaching SVR12.
3. Trial Design
The registry describes this as an open-label Phase 3 study, with non-randomized allocation, no masking, and a single-group model. It records enrollment of 185 and a status of terminated. The listed start was 2011-12 and primary completion was 2014-02. The reason for termination is not reported in the registry record.
The arm descriptions identify three HAART-background regimen groups: ATV/r-based, EFV-based, and RAL-based. Participants in these groups received telaprevir with pegylated interferon alfa 2a and ribavirin. The record describes different telaprevir schedules for the groups, but the arm-description text is incomplete. The full dosing details and any explanation for regimen selection are not reported in the registry record.
Although the registry classifies the study model as single-group, it reports results categories for the listed HAART regimen groups. These are not randomized treatment arms. Participants were not assigned by randomization, and the record does not establish that the groups were comparable on baseline characteristics or other factors. Any differences between group outcomes could therefore reflect differences in the participants or their care, as well as the regimen context.
The study's stated purpose was to treat people coinfected with HIV and HCV with the three-drug HCV regimen and assess an undetectable HCV RNA result after treatment. The registry also lists HAART as an intervention, reflecting the background antiretroviral regimens. Further information about eligibility criteria, recruitment, the reasons for selecting these HAART regimens, and the study's termination is not reported in the registry record. Those omissions limit how fully the study conduct can be reconstructed from the 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: Efficacy analyses were reported as per highly active antiretroviral therapy (HAART) treatment (reporting arms) and also separately as per prior response (in categories) (Treatment-Naive, Prior Relapser, Prior Null Responder, Prior Partial Responder as well as for Total Participants), unless otherwise specified.
Overall Study
| Stage | T/PR + HAART Regimen (ATV/r-Based) | T/PR + HAART Regimen (EFV-Based) | T/PR + HAART Regimen (RAL-Based) |
|---|---|---|---|
| STARTED | 55 | 69 | 61 |
| Treated | 54 | 69 | 59 |
| COMPLETED | 46 | 52 | 45 |
| NOT COMPLETED | 9 | 17 | 16 |
Reasons for not completing this period:
| Reason | T/PR + HAART Regimen (ATV/r-Based) | T/PR + HAART Regimen (EFV-Based) | T/PR + HAART Regimen (RAL-Based) |
|---|---|---|---|
| No Study Medication | 1 | 0 | 2 |
| Adverse Event | 1 | 2 | 0 |
| Death | 0 | 0 | 1 |
| Lost to Follow-up | 2 | 5 | 3 |
| Withdrawal of Consent | 3 | 7 | 7 |
| Study Terminated by Sponsor | 1 | 3 | 3 |
| Other | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Safety Set included all participants who received at least 1 dose of study drug. Here, n = participants evaluable for specified category for each arm, respectively.
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: The Full Analysis Set (FAS), included all randomized participants who received at least 1 dose of study drug.
| Characteristic | Unit | T/PR + HAART Regimen (ATV/r-Based) | T/PR + HAART Regimen (EFV-Based) | T/PR + HAART Regimen (RAL-Based) | Total |
|---|---|---|---|---|---|
| Participants analysed | 54 | 69 | 59 | 182 | |
| Age, Continuous | years | 50.4 (SD 8.81) | 49.6 (SD 8.84) | 48.4 (SD 9.58) | 49.5 (SD 9.06) |
| Sex: Female, Male: Female | Participants | 6 | 9 | 15 | 30 |
| Sex: Female, Male: Male | Participants | 48 | 60 | 44 | 152 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Sustained Viral Response 12 Weeks After Last Planned Dose of Study Drug (SVR12), measured over 12 weeks after last planned dose of study drug (up to Week 60).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with sustained viral response 12 weeks after the last planned dose of study drug, labelled SVR12. The registry defines SVR12 as undetectable HCV RNA at that time. HCV RNA was measured with the Roche TaqMan HCV RNA assay, with a lower limit of quantification of 25 IU/mL; the endpoint description defines undetectable as an HCV RNA level less than that limit.
SVR12 is a binary outcome at the participant level: each evaluable participant either meets the stated virologic definition at the specified follow-up or does not. Reporting a percentage describes how often the endpoint was met in the evaluated group. Its interpretation depends on knowing the numerator, the denominator, and how participants without a measurement were handled. The registry says that the Safety Set includes participants who received at least 1 dose of study drug and that the number evaluable for a specified category can vary by arm.
As a general statistical point, a sustained-response endpoint assesses viral RNA at a defined time after planned treatment, rather than only at the end of treatment. That follow-up helps distinguish a response persisting after treatment from an end-of-treatment measurement alone. It does not, by itself, show what would have happened under another treatment or without treatment. The SVR12 result and its uncertainty are not reported in the registry record, so the magnitude and precision of the observed response cannot be described.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary result needed to answer the study question is not reported in the registry record. There is no posted SVR12 percentage, numerator, denominator, confidence interval, or test result among the registry entries. The record also lists no analyses. Consequently, the posted results do not allow a quantitative statement about the proportion of participants who reached SVR12 or the precision of that proportion.
The study's non-randomized design is central to interpreting its regimen groups. The groups are described by baseline HAART regimen, but were not formed through random assignment. They therefore cannot be treated as exchangeable comparison groups. Any observed difference between them would not, on its own, identify an effect of one regimen context versus another. Participant characteristics, clinical decisions, or other differences could also contribute. The record does not report an adjusted analysis that might address such differences.
The registry's single-group model and its listed regimen groups also call for care in describing the design. The groups provide context for reporting, but the study is not a randomized comparison with a control arm. It is appropriate to describe the study as evaluating the listed treatment combination in a coinfected population and to report the record's group definitions. It would not be appropriate to present a causal comparison of the HAART backgrounds from the design information available.
The registry does report safety counts by group. For serious adverse events, it lists 7 affected participants among 54 at risk in the ATV/r-based group, 8 among 69 in the EFV-based group, and 9 among 59 in the RAL-based group. These counts describe the recorded serious-adverse-event experience in each group, not a randomized comparative estimate. The registry's listed serious-event terms include Anaemia at 6.8%; Neutropenia, Leukocytosis, Vomiting, Escherichia urinary tract infection, and Psoas abscess are each listed at 1.9%. The record does not give enough detail in the registry record to interpret those terms as comparative risks or to attribute them to a particular drug.
Enrollment is recorded as 185, but this is not a substitute for the number evaluable for SVR12. The endpoint description explicitly allows the evaluable number to vary by category and arm. The primary-outcome denominator and missing-outcome handling are not reported in the registry record. Thus neither enrollment nor the safety denominators should be used to reconstruct an efficacy percentage.
The registry status is terminated, but the reason and its implications for completion of planned analyses are not reported in the registry record. Termination alone does not establish whether the study stopped early, why it stopped, or how that status affected the reported outcomes. Overall, the posted information supports a description of the design and the available safety counts, but not a numerical efficacy conclusion.
9. Statistical Methods Explained
The registry identifies the primary measure as a percentage of participants with an event, where the event is meeting the SVR12 definition. This is a binary endpoint: the participant either has undetectable HCV RNA at the specified follow-up or does not. A percentage is useful for expressing the observed frequency in a defined population, but it needs its numerator and denominator to be interpretable. Neither the primary result nor its denominator is reported in the registry record.
What does a confidence interval communicate?
As a general statistical explanation, a confidence interval describes the uncertainty around an estimated quantity, such as a response proportion. A narrow interval indicates greater precision under the method's assumptions; a wide interval indicates less precision. It does not remove design limitations, including the absence of random assignment. No confidence interval for SVR12 is reported in the registry record, so its precision cannot be assessed from the posted results.
What does the study design allow?
The registry reports non-randomized allocation, no masking, and a single-group model. It also reports three groups distinguished by the HAART regimen being received at baseline. Because allocation was not randomized, these groups should not be interpreted as if they were balanced by design. General statistical reasoning cautions that contrasts across non-randomized groups may mix treatment-context differences with differences in participant characteristics and care. The registry entries do not report covariate-adjusted results, so no adjustment can be assumed.
Open-label status means the study is recorded as having no masking. In general, knowledge of treatment can affect aspects of care, reporting, or assessment, depending on the outcome and study procedures. The primary endpoint is based on a laboratory assay, but the registry entries do not describe blinded laboratory assessment or other safeguards. Those procedures are not reported in the registry record.
Why does the assay threshold matter?
The endpoint is not defined as an arbitrary change in HCV RNA. It uses a threshold: undetectable HCV RNA at follow-up, defined as a level less than the assay's lower limit of quantification of 25 IU/mL. This makes the binary classification dependent on the assay and threshold stated in the record. As a general point, a value below a quantification limit is not the same as proof that no viral material exists; it means the measurement meets the study's operational definition. The registry identifies the Roche TaqMan HCV RNA assay, but further information about assay handling and quality procedures is not reported in the registry record.
What is the role of the secondary outcomes?
The registry lists SVR24, rapid viral response, extended rapid viral response, undetectable HCV RNA at end of treatment, adverse events and serious adverse events, maximum, minimum, and average plasma concentrations, and telaprevir-resistant HCV variants at the NS3-4A region. These outcomes address different questions and time points. They should not be substituted for the primary SVR12 outcome. Their results and analysis methods are not reported in the registry record in the registry record for this study.
How should the planning illustrations be understood?
The posted sample-size material is described as a planning illustration computed from the observed effect, not as the trial's own design or as observed power. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event tables, the planning quantity is total events; for other outcomes, it is participants per arm. These are general planning assumptions, not evidence that the trial was designed or conducted with those properties.
A sample-size illustration estimates the amount of information that might be needed under specified assumptions. It does not demonstrate that the study had a particular probability of detecting an effect after completion. In particular, it must not be read as observed power. The registry entries do not include the illustrated sample-size values or a trial-specific sample-size justification. The record does not report a planned comparison between two randomized arms, and the non-randomized regimen groups are not a like-for-like control comparison.
What analysis can be verified?
The registry lists zero analyses. It does not report a statistical model, confidence interval method, hypothesis test, covariate adjustment, interim analysis, or analysis population beyond the primary description of the Safety Set. No test result or p-value is available in the registry record. General explanations of binary outcomes and uncertainty can clarify what such analyses would mean, but they cannot fill in missing study results or methods.
10. Multiplicity, Missing Data and Analysis Populations
The record lists a primary SVR12 outcome and several secondary outcomes, including later sustained response, early response measures, end-of-treatment HCV RNA, safety, drug concentrations, and resistant variants. When a study examines multiple outcomes or multiple comparisons, the chance of at least one apparently notable result can increase. As a general statistical principle, a prespecified multiplicity strategy can help interpret a family of tests. Whether such a strategy was planned or used is not reported in the registry record.
The registry lists no analyses, and no primary or secondary outcome results are reported in the record details. There are no reported hypothesis tests, confidence intervals, or multiplicity adjustments to evaluate. The status of each outcome as prespecified or exploratory beyond the registry's primary and secondary labels is not reported in the registry record.
For the primary outcome, the registry says that the Safety Set includes participants who received at least 1 dose of study drug. It also says that the number evaluable for a specified category can vary by arm. The primary outcome denominator, number with missing follow-up HCV RNA, and handling of missing endpoint data are not reported in the registry record. The record does not say whether missing measurements were counted as not achieving SVR12, excluded, imputed, or handled in another way. No assumption about the missing-data method should therefore be made.
The registry enrollment of 185 and the safety denominators do not establish the primary efficacy denominator. A reader cannot infer endpoint completeness or reconstruct the SVR12 percentage from those figures. The analysis population for secondary outcomes and any distinctions between intention-to-treat, per-protocol, or other populations are not reported in the registry record.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| T/PR + HAART Regimen (ATV/r-Based) | 7 | 54 | 13.0% |
| T/PR + HAART Regimen (EFV-Based) | 8 | 69 | 11.6% |
| T/PR + HAART Regimen (RAL-Based) | 9 | 59 | 15.3% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| T/PR + HAART Regimen (ATV/r-Based) | 54 of 54 |
| T/PR + HAART Regimen (EFV-Based) | 66 of 69 |
| T/PR + HAART Regimen (RAL-Based) | 56 of 59 |
Most frequent serious adverse event terms
| Event term | Organ system | T/PR + HAART Regimen (ATV/r-Based) | T/PR + HAART Regimen (EFV-Based) | T/PR + HAART Regimen (RAL-Based) |
|---|---|---|---|---|
| Anaemia | Blood and lymphatic system disorders | 0 of 54 | 3 of 69 | 4 of 59 |
| Neutropenia | Blood and lymphatic system disorders | 1 of 54 | 1 of 69 | 1 of 59 |
| Syncope | Nervous system disorders | 0 of 54 | 1 of 69 | 1 of 59 |
| Leukocytosis | Blood and lymphatic system disorders | 1 of 54 | 0 of 69 | 0 of 59 |
| Diarrhoea | Gastrointestinal disorders | 0 of 54 | 0 of 69 | 1 of 59 |
| Mallory-Weiss syndrome | Gastrointestinal disorders | 0 of 54 | 1 of 69 | 0 of 59 |
| Rectal haemorrhage | Gastrointestinal disorders | 0 of 54 | 0 of 69 | 1 of 59 |
| Vomiting | Gastrointestinal disorders | 1 of 54 | 0 of 69 | 0 of 59 |
| Escherichia urinary tract infection | Infections and infestations | 1 of 54 | 0 of 69 | 0 of 59 |
| Pneumonia | Infections and infestations | 0 of 54 | 1 of 69 | 0 of 59 |
Most frequent non-serious adverse event terms
| Event term | Organ system | T/PR + HAART Regimen (ATV/r-Based) | T/PR + HAART Regimen (EFV-Based) | T/PR + HAART Regimen (RAL-Based) |
|---|---|---|---|---|
| Fatigue | General disorders | 26 of 54 | 36 of 69 | 30 of 59 |
| Nausea | Gastrointestinal disorders | 23 of 54 | 22 of 69 | 19 of 59 |
| Pruritus | Skin and subcutaneous tissue disorders | 22 of 54 | 21 of 69 | 18 of 59 |
| Headache | Nervous system disorders | 15 of 54 | 17 of 69 | 20 of 59 |
| Anaemia | Blood and lymphatic system disorders | 15 of 54 | 21 of 69 | 16 of 59 |
| Rash | Skin and subcutaneous tissue disorders | 16 of 54 | 20 of 69 | 11 of 59 |
| Diarrhoea | Gastrointestinal disorders | 13 of 54 | 21 of 69 | 6 of 59 |
| Insomnia | Psychiatric disorders | 9 of 54 | 14 of 69 | 14 of 59 |
| Vomiting | Gastrointestinal disorders | 10 of 54 | 11 of 69 | 11 of 59 |
| Neutropenia | Blood and lymphatic system disorders | 10 of 54 | 15 of 69 | 4 of 59 |
Serious events with the highest arm-level rate: anaemia (6.8%), neutropenia (1.9%), leukocytosis (1.9%), vomiting (1.9%), escherichia urinary tract infection (1.9%).
The registry lists serious adverse events by HAART-background group. It records 7 affected participants among 54 at risk in the ATV/r-based group, 8 among 69 in the EFV-based group, and 9 among 59 in the RAL-based group. These are descriptive counts for the groups as recorded. Since allocation was non-randomized, they do not provide a like-for-like comparison of safety between regimens.
The most frequently listed serious-event term is Anaemia at 6.8%. Neutropenia, Leukocytosis, Vomiting, Escherichia urinary tract infection, and Psoas abscess are each listed at 1.9%. These term percentages should be read as registry-reported descriptions, not as evidence of causation or as comparative estimates. The record does not report the methods used to determine attribution or whether participants could contribute more than one event term.
The registry also lists other adverse-event counts of 54 among 54 at risk for the ATV/r-based group, 66 among 69 for the EFV-based group, and 56 among 59 for the RAL-based group. The death counts are not reported in the registry record. Without further definitions, follow-up detail, and analysis methods, these figures do not establish the duration of exposure or the comparative safety of the regimens.
12. What the Result Does, and Does Not, Mean
The registry record describes a Phase 3 study of telaprevir, pegylated interferon alfa 2a, and ribavirin in people coinfected with HIV and genotype 1 HCV. Its primary question concerns undetectable HCV RNA 12 weeks after the last planned dose. The record specifies the assay and threshold used to define that outcome, and describes a Safety Set that includes participants who received at least 1 dose of study drug.
However, the SVR12 percentage, its numerator and denominator, and any uncertainty estimate are not reported in the registry record. Therefore, the posted information cannot quantify how often the primary endpoint was reached or how precise an estimate would be. It also cannot support a numerical efficacy conclusion based on the enrollment figure or safety counts.
The design does not support a randomized treatment comparison. The study is recorded as non-randomized, open-label, and single-group, while the listed outcome groups reflect different HAART regimens at baseline. Differences among those groups cannot be interpreted as causal effects of the HAART background from the design information available. There is no randomized control group listed.
The reported serious adverse-event counts and event terms describe what the registry records for safety. They do not establish that a particular drug caused an event, and they do not enable a fair comparative safety estimate across non-randomized groups. More detailed information about exposure, event definitions, attribution, and missing safety follow-up is not reported in the registry record.
In short, the record establishes the intended endpoint, broad design, regimen-group context, and some safety summaries. It does not report the primary efficacy result, the statistical analyses, or the reason for termination. Those gaps define what can and cannot be concluded from the posted information; they are not evidence for either a positive or a negative treatment effect.
13. Why This Trial Matters Statistically
This study illustrates why statistical interpretation starts with design and outcome reporting, not only with the treatment names. The registry identifies a clinically specific population—people coinfected with HIV and genotype 1 HCV—and a clearly defined virologic endpoint measured after the last planned dose. It also identifies the assay and threshold, which make the endpoint's operational meaning explicit.
At the same time, the non-randomized design limits comparisons among the HAART-background groups. The groups may be useful for describing the treatment contexts represented in the study, but their results cannot be treated as though randomization made them comparable. This distinction matters whenever data are organized into multiple groups: visible group labels do not, by themselves, establish a valid control comparison.
The record also shows why an endpoint definition is not a result. Knowing that SVR12 was the primary outcome does not reveal the observed response proportion, its denominator, or its precision. Without those elements, readers cannot evaluate the magnitude of the primary finding. A stated enrollment count likewise cannot replace the evaluable denominator for a particular outcome.
Finally, the listed adverse-event summaries answer a different question from the primary virologic endpoint. They provide descriptive safety information but do not establish causality or comparative risk in a non-randomized study. The absence of reported analyses, missing-data procedures, and a reason for termination further constrains interpretation. Together, these features make this record a useful example of separating what the design and registry definitions establish from what the missing outcome and analysis details leave unresolved.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The primary limitation for interpreting efficacy is that the registry record does not report the SVR12 result. It also does not report the endpoint numerator, denominator, confidence interval, p-value, or analysis method. The number enrolled is recorded as 185, but the endpoint description says evaluable numbers can vary by arm and category. The primary efficacy population therefore cannot be reconstructed from enrollment.
The non-randomized allocation and absence of masking limit causal interpretation. The ATV/r-based, EFV-based, and RAL-based groups are not randomized control groups, so differences between their outcomes, if reported, would be vulnerable to confounding. The record does not report baseline characteristics or adjusted analyses that could clarify comparability.
The registry status is terminated, but the reason is not reported in the registry record. It is therefore not possible to determine from this information whether termination affected follow-up, planned analyses, or completeness of outcome reporting. The arm descriptions are truncated, and further dosing and implementation details are not available in the registry entries.
Missing-data procedures, multiplicity handling, interim analyses, and a trial-specific sample-size justification are not reported in the registry record. The registry's listed planning illustrations are not the same as the trial's own design justification, and their numerical values are not part of the recorded details available for interpretation. Safety counts are also limited by the lack of further detail on exposure duration, event attribution, and event-level handling. These limitations do not imply a particular treatment result; they indicate which judgments the registry record cannot support.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study to Treat Subjects With Telaprevir, Ribavirin, and Peginterferon Who Are Coinfected With HIV and Hepatitis C Virus (HCV) — NCT01467479.
- Registry record last updated 2015-03-17; status last verified 2015-03.
- Results first posted 2015-03-17.
- 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.
Continue through the Clinical Biostats statistical pathway
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18. Record Summary
The registry record identifies NCT01467479 as an open-label Phase 3 study of telaprevir with pegylated interferon alfa 2a and ribavirin in people coinfected with HIV and genotype 1 HCV. It records non-randomized allocation, no masking, a single-group model, enrollment of 185, and terminated status. The listed study dates are 2011-12 for start and 2014-02 for primary completion.
The primary outcome is SVR12, defined as undetectable HCV RNA 12 weeks after the last planned dose, using the Roche TaqMan HCV RNA assay and a lower limit of quantification of 25 IU/mL. Three HAART-background groups are listed. The primary result, statistical analyses, missing-data methods, reason for termination, and death counts are not reported in the registry record. Safety summaries include serious adverse-event counts by group and listed serious-event terms.