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 Post Marketing Surveillance Study Assessing the Long-term Efficacy and Safety of Aptivus Co-administered With Low-dose Ritonavir in Treatment Experienced Patients With HIV-1 Infection in the Daily Clinical Practice. (NCT00976950), a registered phase not stated study. The primary outcome is Number of Patients Reporting Adverse Events (AE).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00976950 |
| Phase | Phase not stated |
| Condition | HIV Infections |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 42 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Boehringer Ingelheim |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned treatment-experienced patients with advanced HIV-1 infection. Its stated aim referred to patients who had developed resistance to more than one protease inhibitor. The registry record lists an enrollment of 42; further participant characteristics and eligibility details are not reported in the registry record.
Intervention
Patients received tipranavir, marketed as Aptivus, co-administered with low-dose ritonavir. The registry describes the study as post-marketing surveillance in daily clinical practice. Details of dose, prescribing decisions, and treatment duration beyond the outcome timeframe are not reported in the registry record.
Comparator
No like-for-like control comparison is reported. The record lists a group titled Aptivus and Ritonavir, and allocation is not stated. The data therefore describe the treatment group rather than a randomized contrast between treatment strategies.
Primary question
The primary endpoint asks how many treated-set participants reported any type of adverse event over 48 weeks. The stated treated set is defined as patients treated with Aptivus. The registry also names virologic response and change in CD4+ cell count from baseline at Week 48 as secondary outcomes, but their numerical results are not reported in the registry record.
3. Trial Design
The registry describes a completed post-marketing surveillance study of tipranavir, or Aptivus, co-administered with low-dose ritonavir. Its stated setting is daily clinical practice, and its aim was to evaluate safety and virological and immunological efficacy in treatment-experienced patients with advanced HIV-1 infection who had developed resistance to more than one protease inhibitor. Enrollment was 42.
The record identifies one group, titled Aptivus and Ritonavir. Allocation is not stated, and no like-for-like control comparison is described. Consequently, the study information supports a descriptive account of observations in the listed treatment group, not a randomized comparison of treatment strategies. Further design details, including how participants were selected or followed, are not reported in the registry record.
The primary outcome is the number of patients reporting adverse events, with a timeframe of 48 weeks. The outcome description specifies any type of adverse event, and its stated population is the treated set, defined as patients treated with Aptivus. The named secondary outcomes are virologic response and change in CD4+ cell count from baseline at Week 48. Their definitions, assessment procedures, and numerical results are not reported in the registry record.
The record gives a start of 2009-09, a primary completion of 2011-07, and a completed status. These dates describe the registry record’s study timeline; they do not establish how long each participant was observed. Individual follow-up, discontinuation, and completeness of outcome collection 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
| Stage | Aptivus and Ritonavir |
|---|---|
| STARTED | 42 |
| COMPLETED | 36 |
| NOT COMPLETED | 6 |
Reasons for not completing this period:
| Reason | Aptivus and Ritonavir |
|---|---|
| Adverse Event | 3 |
| Events with no relationship to Aptivus | 3 |
Analysis population for the primary outcome, as defined in the registry: Treated set (TS), defined as patients treated with Aptivus
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.
| Characteristic | Unit | Aptivus and Ritonavir |
|---|---|---|
| Participants analysed | 42 | |
| Age, Continuous | years | 25.5 (SD 10.4) |
| Sex: Female, Male: Female | Participants | 19 |
| Sex: Female, Male: Male | Participants | 23 |
| Baseline HIV RNA values: <= 50 copies/ml | Participants | 0 |
| Baseline HIV RNA values: 51 - <1,000 copies/ml | Participants | 1 |
| Baseline HIV RNA values: 1,000 - <10,000 copies/ml | Participants | 5 |
| Baseline HIV RNA values: 10,000 - <100,000 copies/ml | Participants | 13 |
| Baseline HIV RNA values: 100,000 - <1,000,000 copies/ml | Participants | 12 |
| Baseline HIV RNA values: >= 1,000,000 copies/ml | Participants | 0 |
| Baseline HIV RNA values: Missing | Participants | 11 |
| Baseline CD4+ count: <= 50 cells/mm^3 | Participants | 2 |
| Baseline CD4+ count: 51 - <251 cells/mm^3 | Participants | 19 |
| Baseline CD4+ count: 251 - <451 cells/mm^3 | Participants | 13 |
| Baseline CD4+ count: >= 451 cells/mm^3 | Participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Patients Reporting Adverse Events (AE), measured over 48 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of treated-set participants reporting adverse events over 48 weeks. The record describes the event scope as any type of adverse event and defines the treated set as patients treated with Aptivus. This is a count-based safety measure: it is intended to describe how many people in the stated population experienced or reported an event during the specified timeframe.
In general, safety surveillance uses adverse-event reporting to characterize unwanted events observed during treatment and follow-up. A count can be informative about the burden of reported events in the group, but by itself it does not establish that treatment caused an event. Attribution, event severity, timing, and the way events were collected all affect interpretation. Details of those procedures are not reported in the registry record.
The primary endpoint’s title and definition do not specify a comparison group or a statistical contrast. The registry’s serious-event summary is a separate safety detail; it should not be treated as the complete result for the broader primary endpoint, which includes any type of adverse event. A numerical result for the primary endpoint itself is not reported in the registry record. The serious-event counts and listed serious-event term are described separately in the safety reading.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record identifies a safety question in a treatment-experienced population and lists an enrollment of 42. Its primary endpoint concerns the number of treated-set participants reporting any type of adverse event over 48 weeks. However, a numerical result for that broad primary endpoint is not reported in the registry record. The serious-event summary contains some safety counts, but it does not substitute for a reported count covering all adverse events.
The registry lists 1 in the serious-event affected count among 42 at risk, and 0 in the other adverse-event affected count among 42 at risk. It also lists pulmonary tuberculosis at 2.4% among the top serious-event terms. These are descriptive figures in the record. They do not identify a treatment effect, establish causation, or show how event risk compares with another group. The record does not report a control group suitable for a like-for-like comparison.
No numerical results for virologic response or change in CD4+ cell count from baseline at Week 48 are reported in the registry record. Thus the study’s stated interest in virological and immunological efficacy cannot be evaluated from these results. The absence of those results is not evidence that no outcomes were measured; it means that numerical findings are not reported in the registry record.
In general, estimates from small descriptive groups can be imprecise, particularly for uncommon outcomes. A confidence interval, when reported, conveys a range of values compatible with the observed data under a statistical model; it does not guarantee that the true value lies in that range. No confidence interval or other precision estimate for the primary endpoint is reported in the registry record. Nor are p-values or inferential analyses reported.
The study’s post-marketing, daily-practice framing is relevant to the type of question asked: it concerns observations in clinical use rather than a documented randomized contrast. But the record does not report enough detail about participant selection, event ascertainment, follow-up completeness, or potential confounding to assess how these features might affect the observed counts. Interpretation should therefore remain limited to the specific descriptive information recorded, without extending it to comparative effectiveness or causal safety conclusions.
Planning illustrations, where available, are not evidence about the observed study result. They are calculations based on assumptions for a hypothetical design and should not be read as observed power or as a replacement for reported outcome estimates. Numerical planning outputs are not reported in the registry record.
9. Statistical Methods Explained
The registry record names a count-based primary safety endpoint and describes a group receiving Aptivus and Ritonavir. It does not report analysis records, confidence intervals, p-values, or numerical results for the broad primary endpoint. The methods below explain how this kind of information is generally interpreted; they do not assert that any particular unreported procedure was used in this study.
What does a count-based endpoint represent?
In general, a count of participants with an event describes how many people in a defined analysis population experienced the event during a stated period. The denominator matters: a count without the number of people at risk is difficult to interpret. The primary endpoint specifies the treated set and a 48-week timeframe, but its numerical result is not reported in the registry record. The serious-event summary separately gives 42 at risk for the listed treatment group.
A count of affected participants is not necessarily the same as a count of all event occurrences. One person may experience more than one event, and summaries may count people, events, or both. The endpoint is worded as the number of patients reporting adverse events, but further rules for counting multiple events are not reported in the registry record. The safety summary’s affected counts should therefore be read according to the category stated there, not expanded into an unreported total event count.
Why does the comparison structure matter?
In general, a treatment comparison requires groups that can be meaningfully contrasted and a clear account of how those groups were formed. Random allocation can help balance known and unknown prognostic factors on average, while observational comparisons may be affected by differences in patient characteristics and treatment decisions. Here, allocation is not stated and a like-for-like control comparison is not reported. As a result, the listed counts are descriptive, rather than an estimate of a contrast between treatments.
Even when a single group has a clearly defined denominator, its event frequency cannot by itself distinguish treatment-related events from events that would occur because of the underlying condition, other care, or unrelated causes. General causal interpretation requires an appropriate comparison and assumptions about how participants entered each group and how outcomes were measured. Such details are not reported in the registry record.
What would precision measures add?
In general, a confidence interval communicates uncertainty around an estimated quantity. For a participant count or event proportion, its width depends in part on the amount of information and the number of observed events. Sparse events can yield considerable uncertainty, so a point estimate should not be read as exact knowledge of the underlying frequency. The registry record does not report a confidence interval for the primary endpoint or the serious-event counts.
A p-value, in general, assesses how compatible data are with a specified null model under its assumptions. It does not measure the probability that a treatment is effective or harmful, nor does it establish clinical importance. No inferential analysis or p-value is reported in the registry record. Without a stated comparison and its analysis, there is no reported hypothesis test to interpret.
How should planning illustrations be read?
General sample-size planning estimates depend on assumptions about the effect to detect, significance level, allocation, and analysis method. The registry’s planning assumptions specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. For time-to-event calculations, the assumptions describe total events using the Schoenfeld approach; other calculations are expressed as participants per arm.
These are planning assumptions, not evidence that the trial enrolled two arms or used those methods in its own design. The record does not state that these assumptions were the trial’s original design plan, and numerical planning outputs are not reported in the registry record. Planning estimates must not be described as observed power: observed power is not a substitute for interpreting an effect estimate and its uncertainty.
In general, over-dispersion matters when variability in count data is greater than a simple model assumes. If ignored, it can make standard errors too small and intervals too narrow. Whether over-dispersion is relevant depends on the outcome structure and model. No count model, dispersion estimate, or adjustment for over-dispersion is reported in the registry record, so none should be inferred.
10. Multiplicity, Missing Data and Analysis Populations
The registry names a primary safety outcome and two secondary outcomes: virologic response and change in CD4+ cell count from baseline at Week 48. Numerical results for the secondary outcomes are not reported in the registry record. The record does not report a multiplicity procedure, such as an adjustment for assessing several outcomes, nor does it describe a hierarchy for interpreting them. Without that information, the handling of multiple outcome tests cannot be assessed.
Missing-data methods are also not reported in the registry record. The record does not state how participants with incomplete follow-up, missing measurements, treatment discontinuation, or unavailable outcome assessments were handled. It does not report the number of participants with evaluable results for the primary or secondary outcomes. Enrollment of 42 should therefore not be assumed to mean that every participant contributed complete data through the 48-week timeframe.
The primary endpoint population is described as the treated set, defined as patients treated with Aptivus. The registry record does not give further analysis-population definitions for the secondary outcomes or explain whether the same participants contributed to each analysis. It also does not report a protocol-defined intention-to-treat population or other analysis sets. These omissions limit assessment of selection caused by treatment exposure or missing outcome information.
In general, missing outcomes can bias an estimate if the likelihood of missingness is related to participants’ outcomes or characteristics. Methods such as imputation or sensitivity analyses may explore that uncertainty, but no such methods are reported in the registry record. The available information does not establish whether missing data occurred or how much they may affect interpretation.
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 |
|---|---|---|---|
| Aptivus and Ritonavir | 1 | 42 | 2.4% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Aptivus and Ritonavir | 0 of 42 |
Most frequent serious adverse event terms
| Event term | Organ system | Aptivus and Ritonavir |
|---|---|---|
| Pulmonary tuberculosis | Infections and infestations | 1 of 42 |
Serious events with the highest arm-level rate: pulmonary tuberculosis (2.4%).
The safety summary lists 42 at risk in the Aptivus and Ritonavir group, with 1 in the serious-event affected count and 0 in the other adverse-event affected count. It also names pulmonary tuberculosis at 2.4% among the top serious-event terms. These figures describe the recorded safety summary; they are not a comparative estimate against an untreated or alternative-treatment group.
The primary endpoint is broader than this serious-event summary: it concerns any type of adverse event among the treated set over 48 weeks. A numerical result for that endpoint is not reported in the registry record. The serious-event counts therefore should not be read as the total number of participants with any adverse event.
In general, event counts and percentages answer different descriptive questions, and neither alone establishes that treatment caused an event. The registry record does not report further details about event attribution, timing, severity beyond the serious-event classification, or how the term-level percentage was calculated. No additional interpretation of those details is warranted from the listed figures alone.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed post-marketing surveillance study enrolled 42 participants and examined tipranavir with low-dose ritonavir in treatment-experienced patients with HIV-1 infection. It identifies adverse events as the primary endpoint and names virologic response and CD4+ cell-count change as secondary outcomes. The safety summary reports 1 in the serious-event affected count and 0 in the other affected count, each among 42 at risk, and lists pulmonary tuberculosis at 2.4% among the top serious-event terms.
Those details do not provide a complete numerical result for the primary endpoint, which covers any type of adverse event. They also do not provide numerical findings for the secondary outcomes. The record therefore does not support a statistical conclusion about the study’s virological or immunological outcomes, nor a full account of all adverse events.
Because no like-for-like control comparison is reported and allocation is not stated, the recorded counts cannot establish how outcomes would differ under another treatment strategy. In general, an event observed during treatment is not, by that fact alone, shown to have been caused by treatment. The record does not supply the comparative design or event-attribution details needed to make such a claim.
Likewise, the absence of a reported confidence interval or inferential analysis means that the precision of the listed counts is not quantified in the registry record. The figures should be read as descriptive observations, not as proof of safety, harm, efficacy, or lack of efficacy. The stated study aim is broader than the numerical results available in the registry record.
The appropriate scope of interpretation is narrow: these are the counts and outcome descriptions recorded for a single listed treatment group. They may inform a description of what the registry reports, but they do not establish comparative benefit or risk, predict an individual patient’s experience, or resolve uncertainty left by unreported outcomes and methods.
13. Why This Trial Matters Statistically
Statistically, this study illustrates the distinction between a stated research aim and the results available for interpretation. The aim includes safety, virological efficacy, and immunological efficacy, while the record identifies a broad adverse-event endpoint and two efficacy-related secondary outcomes. Numerical results for the broad primary endpoint and the secondary outcomes are not reported in the registry record. That gap makes it important to separate the questions the study intended to address from the findings that can actually be described.
The record also highlights why study structure matters. A group receiving Aptivus and Ritonavir is listed, but allocation is not stated and no like-for-like control comparison is described. Descriptive counts can characterize recorded events within a group, while comparative claims require an interpretable contrast and appropriate assumptions. The serious-event counts do not supply that contrast.
In general, a small enrollment can leave estimates for uncommon outcomes imprecise. This is a statistical limitation, not a conclusion about the importance of the observed events. Precision depends on the data and analysis, and no interval estimate for the primary outcome is reported in the registry record. Planning illustrations are also distinct from actual study evidence: they concern hypothetical assumptions and are not observed power.
The trial matters as an example of the care needed when reading post-marketing surveillance records. The setting and stated aim provide context, but missing outcome values, analysis details, and follow-up information constrain what can be inferred. A disciplined reading preserves the descriptive information that is reported while avoiding conclusions that would require an unreported comparison, analysis, or outcome result.
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.
Several trial-specific limitations follow from the registry information. The study lists one treatment group, and allocation is not stated. No like-for-like control comparison is reported, so the safety counts cannot estimate a difference between treatment strategies. The registry record does not report a comparator group’s outcomes or a comparative analysis.
The broad primary endpoint is defined as any type of adverse event among treated-set participants over 48 weeks, but its numerical result is not reported in the registry record. The safety summary gives serious-event and other-event affected counts, yet it does not provide the complete result for all adverse events. The named secondary outcomes also lack numerical results in the registry record.
The record does not report participant characteristics beyond the stated treatment-experienced, advanced HIV-1 population and the aim’s reference to resistance to more than one protease inhibitor. Eligibility criteria, baseline clinical measures, treatment exposure details, and individual follow-up are not reported in the registry record. These omissions limit assessment of how representative the participants were and how consistently outcomes were observed.
Further limitations include unreported methods for event collection and attribution, missing-data handling, analysis populations beyond the treated-set definition, and statistical analysis. The record also does not report confidence intervals, p-values, or a multiplicity approach. These gaps prevent assessment of precision, outcome completeness, and the treatment of multiple endpoints. They are limits of what can be concluded from the registry record, not evidence that a particular method was or was not used.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Post Marketing Surveillance Study Assessing the Long-term Efficacy and Safety of Aptivus Co-administered With Low-dose Ritonavir in Treatment Experienced Patients With HIV-1 Infection in the Daily Clinical Practice. — NCT00976950.
- Registry record last updated 2014-03-20; status last verified 2014-02.
- Results first posted 2012-08-16.
- 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.
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18. Record Summary
NCT00976950 is a completed post-marketing surveillance study of tipranavir, or Aptivus, co-administered with low-dose ritonavir in treatment-experienced patients with HIV-1 infection. The record lists an enrollment of 42 and describes the setting as daily clinical practice. Its primary outcome is the number of treated-set participants reporting any type of adverse event over 48 weeks.
The safety summary lists 1 in the serious-event affected count and 0 in the other affected count among 42 at risk in the Aptivus and Ritonavir group. Pulmonary tuberculosis is listed at 2.4% among the top serious-event terms. Numerical results for the broad primary endpoint and the named secondary outcomes are not reported in the registry record. Allocation is not stated, and no like-for-like control comparison is reported.