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 of Raltegravir in a Diverse Cohort of HIV-Infected Patients (0518-055) (NCT00764946), a non-randomized phase 3 study. The primary outcome is Number of Participants Who Achieved HIV Ribonucleic Acid (RNA) <50 Copies/mL at Week 48.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00764946 |
| Phase | Phase 3 |
| Condition | Human Immunodeficiency Virus |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 209 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
People with HIV, including people who had received antiretroviral drugs before and people who had not. The study summary describes a diverse cohort intended to include at least 50% African American participants and at least 25% female participants; the achieved proportions are not reported in the registry record.
Intervention
Raltegravir, described in the study summary as taken twice daily.
Comparator
There was no separate control group. The registry record identifies a single-group study, so the intervention was not compared with a concurrent alternative treatment or placebo group.
Primary question
How many participants achieved HIV RNA below 50 copies/mL at Week 48?
The primary endpoint is a count of participants meeting a viral-load threshold at a specified follow-up time. It is a measure of virologic response, rather than a direct comparison of treatment strategies. The record also lists outcomes concerning HIV RNA below 400 copies/mL, change in HIV RNA, change in CD4 cell count, and loss of virologic response. These are listed as secondary outcomes, but their results are not reported in the registry record.
Because the study had a single group and was not randomized, it can describe outcomes among participants who received raltegravir under the study conditions. It cannot by itself establish how those outcomes would differ under another treatment or under no treatment. The primary result needed to describe the observed Week 48 response—the number meeting the threshold—is not reported in the registry record, so the clinical question cannot be answered from the posted results.
3. Trial Design
This was a Phase III, open-label, non-randomized, single-group study of raltegravir in people with HIV. The registry record lists an enrollment of 209. The study began in 2008-10, had primary completion in 2011-02, and is marked completed. Merck Sharp & Dohme LLC is listed as the sponsor.
The study summary describes a diverse cohort that included participants who had received antiretroviral drugs before and participants who had not. It states that at least 50% of participants were to be African American and at least 25% were to be female. Those statements describe the intended cohort composition; the achieved proportions are not reported in the registry record. The adverse-event groups are described by treatment history: treatment experienced and failing current therapy, treatment experienced and intolerant to current therapy, and treatment naive.
Open-label means the treatment was not masked from participants or investigators. Non-randomized and single-group mean that participants were not assigned by random allocation to competing study arms. The intervention label in the record refers to raltegravir; it does not indicate a separate control group. Thus, the study design supports description of outcomes and safety events within the treated cohort, but not a like-for-like randomized comparison.
The primary outcome is the number of participants who achieved HIV RNA below 50 copies/mL at Week 48. The registry record also lists seven outcome measures and secondary outcomes including a less stringent viral-load threshold, mean changes in HIV RNA and CD4 cell count, and participants without loss of virologic response. The results for these outcomes are not reported in the registry record. Detailed eligibility criteria, dosing instructions beyond the summary's twice-daily description, and the statistical analysis plan 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 | Participants Failing Current Therapy | Participants Intolerant to Current Therapy | Participants Treatment Naive |
|---|---|---|---|
| STARTED | 98 | 89 | 22 |
| TREATED | 97 | 88 | 21 |
| COMPLETED | 85 | 72 | 18 |
| NOT COMPLETED | 13 | 17 | 4 |
Reasons for not completing this period:
| Reason | Participants Failing Current Therapy | Participants Intolerant to Current Therapy | Participants Treatment Naive |
|---|---|---|---|
| Lack of Efficacy | 1 | 0 | 0 |
| Lost to Follow-up | 3 | 4 | 0 |
| Physician Decision | 2 | 4 | 0 |
| Adverse Event | 3 | 2 | 1 |
| Withdrawal by Subject | 3 | 6 | 2 |
| Never Treated | 1 | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: Efficacy analyses were based on the Full Analysis Set population that included all participants who took at least one dose of study medication and had at least one postbaseline evaluation. The Treatment-Related Discontinuation = Failure approach was used as the primary method for handling missing HIV RNA values.
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 | Participants Failing Current Therapy | Participants Intolerant to Current Therapy | Participants Treatment Naive | Total |
|---|---|---|---|---|---|
| Participants analysed | 97 | 88 | 21 | 206 | |
| Age, Continuous | years | 44.0 (SD 9.2) | 46.9 (SD 9.0) | 38.5 (SD 10.1) | 44.7 (SD 9.5) |
| Sex: Female, Male: Female | Participants | 46 | 44 | 7 | 97 |
| Sex: Female, Male: Male | Participants | 51 | 44 | 14 | 109 |
| Race: Black | Participants | 70 | 69 | 14 | 153 |
| Race: Non-Black | Participants | 27 | 19 | 7 | 53 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Who Achieved HIV Ribonucleic Acid (RNA) <50 Copies/mL at Week 48, measured over Week 48.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants with HIV RNA below 50 copies/mL at Week 48. HIV RNA is the amount of viral genetic material measured in blood; the endpoint classifies participants according to whether their measurement is below the stated threshold at the specified follow-up time. It therefore represents a virologic response at a particular time, not the average change in viral load or a time-to-event outcome.
A threshold-based endpoint can be useful because it expresses response as a clinically interpretable state: below a defined viral-load level at follow-up. It also makes clear that a participant just below the cutoff and one with a much lower measurement both count as meeting the endpoint, while participants at or above the cutoff do not. The count alone does not convey how far individual measurements were from the threshold.
The registry record says that numbers of participants with HIV RNA below 50 copies/mL were summarized by race for each time point. It defines the efficacy population as the Full Analysis Set: participants who took at least one dose of study medication and had at least one postbaseline evaluation. It also names Treatment-Related Discontinuation = Failure as the primary method for handling missing HIV RNA results, but the detailed implementation is not reported in the registry record. The number meeting the primary endpoint at Week 48 is not reported in the registry record, so neither the observed response count nor its precision can be described from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a specific efficacy question: how many participants had HIV RNA below 50 copies/mL at Week 48. However, it does not report that count, an estimate of the response proportion, or a confidence interval for the primary endpoint. The record therefore does not establish the size or precision of the observed Week 48 response. It also does not support a conclusion about whether outcomes differed from another treatment, because the study had no separate control group.
The listed secondary outcomes cover additional aspects of response: HIV RNA below 400 copies/mL, mean change from baseline in HIV RNA, mean change from baseline in CD4 cell count, and participants without loss of virologic response. Their names identify what was intended to be measured, not the results. The values and analyses for these secondary outcomes are not reported in the registry record. No conclusion about their magnitude or uncertainty can be drawn from their titles alone.
The study’s single-group structure matters for interpretation. Any measured outcome would describe participants who received raltegravir in this study, subject to the recorded analysis population and missing-data approach. Without random allocation to a control group, differences from participants in other studies or from historical expectations could reflect differences in participant characteristics, follow-up, or other aspects of care, as well as treatment. Such comparisons are not equivalent to a randomized treatment contrast.
The record reports safety-event counts for groups defined by prior treatment experience, along with several serious-event terms and percentages. These data can be read as descriptive safety information recorded for the study. They do not, on their own, establish that raltegravir caused an event or allow a comparison against an untreated or alternative-treatment group. The registry record does not report deaths for these groups. It also does not explain the denominator or calculation behind the listed percentages for the serious-event terms, or whether participants could contribute more than one event.
In short, the record describes a Phase III study and identifies its planned efficacy measures and some safety counts. The absence of reported primary and secondary endpoint results is a central constraint: the posted information does not permit an assessment of the observed efficacy outcomes or their statistical precision. The study design also limits causal interpretation, even if outcome values were available, because it is non-randomized and single group.
9. Statistical Methods Explained
The methods information in the registry record is limited. It identifies a single-group, non-randomized, open-label design and describes the primary endpoint as a participant count at Week 48. It also names an efficacy analysis population and a primary approach to missing results. Detailed statistical methods, including the analysis model and uncertainty estimates for the primary endpoint, are not reported in the registry record.
What does a single-group result describe?
A single-group analysis describes outcomes among participants who received the study intervention. For a binary endpoint such as achieving a viral-load threshold, an analysis might report the count meeting the criterion and an estimate of the proportion in the analysis population. A confidence interval, when reported, conveys the statistical uncertainty around an estimate under the assumptions of the method. It does not account for every possible source of bias, and it does not create a treatment comparison where no control group exists.
Here, the registry record reports the endpoint definition but not the Week 48 count or an interval estimate. Consequently, the observed response and its precision are not available in the posted results. The record also does not report the statistical method used to estimate uncertainty or whether any covariate adjustment was performed.
Why does allocation matter?
Random allocation is used in comparative trials to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics. This study is listed as non-randomized and single group, with no separate control arm. Its results can describe what happened within the study cohort but cannot isolate a treatment effect by contrasting randomized groups. Observed outcomes may also be influenced by participant characteristics, other care, follow-up, and how missing observations are handled.
What does the analysis population mean?
The record defines the efficacy Full Analysis Set as participants who took at least one dose and had at least one postbaseline evaluation. This definition does not include everyone who may have enrolled: it requires both treatment exposure and a postbaseline assessment. The count in that analysis set is not reported in the registry record. The record does not give a separate count for participants included in the primary endpoint calculation or explain how participants with no postbaseline evaluation were treated.
How should the missing-data approach be understood?
The named primary approach is Treatment-Related Discontinuation = Failure. In general, a missing-data rule determines how an analysis handles outcomes that are not observed, and a rule that treats a specified discontinuation as failure assigns an unfavorable outcome for the relevant endpoint rather than leaving the outcome unclassified. The registry record does not provide the complete wording or implementation details: the description ends before specifying the full handling of missing HIV RNA results. It is therefore not possible to determine from the record exactly which discontinuations or missing observations were classified as failures, or whether other missing-data rules were used in sensitivity analyses.
What can the planning illustrations tell readers?
Any sample-size planning illustrations based on an observed effect are hypothetical planning calculations, not observed power. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is a stated fraction of the observed effect. For time-to-event outcomes, the stated convention is to show a total number of events; for other outcomes, it is participants per arm. These assumptions describe an illustrative future two-arm comparison, not the actual single-group design of this study. The registry record does not report the study’s own sample-size justification, planning assumptions, or power calculation. It also does not report numerical planning estimates that could be interpreted as part of the trial’s observed findings.
What statistical details are not available?
The registry record does not report the model used for the primary analysis, the method for calculating confidence intervals, a statistical test, any covariate-adjustment strategy, or the handling of multiplicity across outcomes. It lists seven outcome measures and identifies secondary outcomes, but does not provide a detailed statistical analysis plan. Interim analyses are not reported in the registry record. These omissions limit evaluation of how the analysis was specified and whether the posted outcome summaries, if available, would reflect prespecified methods.
General statistical principle: for counts or proportions, uncertainty depends on both the number of observed outcomes and the relevant analysis denominator. Neither the primary endpoint count nor its analysis denominator is reported. No precision estimate should therefore be inferred from enrollment alone. General statistical principle: over-dispersion is relevant when outcome variability exceeds what a chosen model expects; whether it matters depends on the outcome and model. The registry record does not identify a model for which over-dispersion could be assessed.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists seven outcome measures, including the primary Week 48 viral-load threshold and secondary measures of viral response, HIV RNA change, CD4 cell-count change, and loss of virologic response. It does not report a multiplicity strategy. Multiplicity concerns the risk of false-positive findings when several outcomes or analyses are considered; methods such as prespecifying a hierarchy or adjusting significance thresholds can address that issue. Whether any such method was planned or used is not reported in the registry record. Because the outcome results and analysis details are also absent, no statement about statistical significance across the outcomes can be made.
The record defines the efficacy Full Analysis Set as participants who received at least one dose and had at least one postbaseline evaluation. It names Treatment-Related Discontinuation = Failure as the primary approach for missing HIV RNA results. This is relevant because the participants included in an analysis and the treatment of missing measurements can affect a binary endpoint count. The record does not report the Full Analysis Set size, the endpoint denominator, the number of missing Week 48 measurements, or the detailed implementation of the missing-data rule.
The registry record does not describe sensitivity analyses for missing data, alternative analysis populations, or whether outcome-specific denominators varied. It also does not report an interim-analysis plan or the statistical analysis plan. These absences prevent assessment of how robust any efficacy finding might be to alternative missing-data assumptions or analytic choices. Since the primary endpoint result itself is not reported, the posted information does not support a quantitative evaluation of missingness or multiplicity effects.
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 |
|---|---|---|---|
| Treatment Experienced - Failing Current Therapy | 15 | 97 | 15.5% |
| Treatment Experienced - Intolerant To Current Therapy | 5 | 88 | 5.7% |
| Treatment Naive | 2 | 21 | 9.5% |
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 |
|---|---|
| Treatment Experienced - Failing Current Therapy | 49 of 97 |
| Treatment Experienced - Intolerant To Current Therapy | 26 of 88 |
| Treatment Naive | 10 of 21 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment Experienced - Failing Current Therapy | Treatment Experienced - Intolerant To Current Therapy | Treatment Naive |
|---|---|---|---|---|
| Meningitis cryptococcal | Infections and infestations | 1 of 97 | 0 of 88 | 1 of 21 |
| Urinary tract infection | Infections and infestations | 1 of 97 | 1 of 88 | 0 of 21 |
| Anaemia | Blood and lymphatic system disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Haemolytic anaemia | Blood and lymphatic system disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Myocardial infarction | Cardiac disorders | 0 of 97 | 1 of 88 | 0 of 21 |
| Sensorineural hearing loss | Ear and labyrinth disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Acute gastritis | Gastrointestinal disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Chronic diarrhoea | Gastrointestinal disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Nausea | Gastrointestinal disorders | 1 of 97 | 0 of 88 | 0 of 21 |
| Vomiting | Gastrointestinal disorders | 1 of 97 | 0 of 88 | 0 of 21 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment Experienced - Failing Current Therapy | Treatment Experienced - Intolerant To Current Therapy | Treatment Naive |
|---|---|---|---|---|
| Nausea | Gastrointestinal disorders | 15 of 97 | 7 of 88 | 1 of 21 |
| Upper respiratory tract infection | Infections and infestations | 12 of 97 | 9 of 88 | 2 of 21 |
| Diarrhoea | Gastrointestinal disorders | 11 of 97 | 5 of 88 | 2 of 21 |
| Vomiting | Gastrointestinal disorders | 11 of 97 | 3 of 88 | 0 of 21 |
| Oral candidiasis | Infections and infestations | 8 of 97 | 0 of 88 | 1 of 21 |
| Headache | Nervous system disorders | 8 of 97 | 1 of 88 | 0 of 21 |
| Low back pain | Musculoskeletal and connective tissue disorders | 2 of 97 | 5 of 88 | 1 of 21 |
| Rash | Skin and subcutaneous tissue disorders | 1 of 97 | 6 of 88 | 1 of 21 |
| Bronchitis | Infections and infestations | 5 of 97 | 2 of 88 | 0 of 21 |
| Cough | Respiratory, thoracic and mediastinal disorders | 5 of 97 | 2 of 88 | 0 of 21 |
Serious events with the highest arm-level rate: meningitis cryptococcal (4.8%), deep vein thrombosis (4.8%), myocardial infarction (1.1%), community acquired pneumonia (1.1%), urinary tract infection (1.1%).
The registry record reports safety counts for three treatment-history groups: treatment experienced and failing current therapy, treatment experienced and intolerant to current therapy, and treatment naive. In those groups, the serious-event figures are 15 affected among 97 at risk, 5 among 88, and 2 among 21, respectively. The other-event figures are 49 among 97, 26 among 88, and 10 among 21, respectively. These are descriptive counts in the registry record, not comparative treatment effects.
The record also lists serious-event terms with percentages: Meningitis cryptococcal, 4.8%; Deep vein thrombosis, 4.8%; Myocardial infarction, 1.1%; Community acquired pneumonia, 1.1%; Urinary tract infection, 1.1%; and Musculoskeletal chest pain, 1.1%. The denominator and calculation underlying these percentages are not reported in the registry record. It is also not reported whether the figures count participants, events, or a grouping that permits multiple events per participant.
These safety data do not establish causation. The record does not provide a separate control group, and deaths are not reported for the listed groups. The counts should therefore be read as events recorded in the study, not as evidence that the study drug caused or prevented them.
12. What the Result Does, and Does Not, Mean
This study’s record identifies a focused virologic endpoint: the number of participants with HIV RNA below 50 copies/mL at Week 48. It also provides the study design, the intended breadth of the cohort, an analysis-population definition, a named missing-data approach, and descriptive safety counts. Those details help explain what the investigators aimed to assess and how at least part of the analysis was framed.
What the registry record does not report is the primary endpoint count or its statistical precision. It also does not report the listed secondary outcome results. Without those results, the posted information cannot show the observed level of viral suppression, the changes in HIV RNA or CD4 cell count, or the frequency of participants without loss of virologic response. The missing endpoint results should not be replaced by assumptions based on the study title, the intervention, or the endpoint definitions.
Even if the outcome values were available, the single-group, non-randomized design would mean that the findings describe the study cohort rather than provide a randomized estimate of how raltegravir compares with another treatment. There is no concurrent control group in the registry record. Therefore, the design cannot separate treatment effects from other influences on observed outcomes with the protection that random allocation is intended to provide.
The safety counts add descriptive information but do not identify whether events were caused by treatment. The listed percentages lack a reported denominator and calculation explanation, so they should not be treated as fully interpretable event rates. The record also does not report deaths for the safety groups.
The appropriate reading is consequently limited: the record documents a completed Phase III study of raltegravir and specifies outcomes of interest, while leaving key efficacy results and important analytical details unreported. It does not establish a comparative benefit or harm, and it does not permit a precise estimate of the primary response from the posted results.
13. Why This Trial Matters Statistically
This trial is statistically notable for the contrast between a clearly defined clinical endpoint and the limited results available in the registry record. The primary outcome specifies both a threshold—HIV RNA below 50 copies/mL—and a follow-up time, Week 48. That makes the intended measurement straightforward to identify. Yet the count needed to describe the observed response is not reported, illustrating why an endpoint definition alone is not an outcome result.
The design also makes a basic interpretive distinction visible. A single-group study can characterize responses and safety events within a cohort, but it does not provide a randomized contrast. The registry record’s non-randomized allocation and absence of a separate control group matter when readers consider whether an observed outcome can be attributed to treatment. This is a design limitation, not a question that can be resolved by choosing a different statistical test after the fact.
The record further names an efficacy population and a missing-data approach. These are important because the denominator and the classification of unobserved outcomes affect a binary response measure. However, the analysis-set size, endpoint denominator, missing-outcome count, and full handling details are not reported. The record therefore illustrates why transparent reporting of analysis populations and missing-data rules is necessary for interpreting an endpoint.
Finally, the safety information is organized by treatment history and includes serious-event counts and selected event terms, but the listed percentages lack a reported denominator. This underscores that a percentage is not fully interpretable without knowing what it represents and how it was calculated. Taken together, the record provides useful design and outcome-definition information while leaving the principal efficacy result and several statistical details unavailable.
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 most consequential limitation for interpreting the posted results is that the registry record does not report the primary Week 48 endpoint value. It also does not report the results of the listed secondary outcomes. As a result, the record does not permit an estimate of response or a description of statistical precision. This absence is distinct from a result showing no response; no such conclusion can be drawn from an unreported result.
The study was non-randomized and single group, with no separate control arm. Its outcomes therefore cannot be interpreted as a randomized comparison with another treatment. The open-label design means treatment was not masked, although the registry record does not describe how this may have affected outcome assessment or reporting.
The intended cohort composition is described in the study summary, including minimum proportions for African American and female participants, but the achieved proportions are not reported in the registry record. Detailed eligibility criteria and participant characteristics are also not reported. The record’s Full Analysis Set definition is available, but the size of that set and the endpoint denominator are not.
Missing HIV RNA results were to be handled primarily using Treatment-Related Discontinuation = Failure, but the registry description is incomplete and does not explain its full implementation. The record does not report the number of missing observations, sensitivity analyses, or the statistical analysis plan. It does not report a multiplicity strategy despite listing multiple outcomes.
For safety, the record lists counts and selected serious-event terms, but does not explain the denominator for the percentages or whether the figures count events or participants. The record does not report deaths in the listed safety groups. These gaps constrain interpretation of both efficacy and safety information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Raltegravir in a Diverse Cohort of HIV-Infected Patients (0518-055) — NCT00764946.
- Registry record last updated 2017-03-21; status last verified 2017-02.
- Results first posted 2012-04-12.
- 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
The record is for NCT00764946, titled “A Study of Raltegravir in a Diverse Cohort of HIV-Infected Patients (0518-055).” It describes a completed, Phase III, open-label, non-randomized, single-group study sponsored by Merck Sharp & Dohme LLC. Enrollment is listed as 209; the study began in 2008-10 and had primary completion in 2011-02.
The primary outcome is the number of participants with HIV RNA below 50 copies/mL at Week 48. The efficacy population is defined as the Full Analysis Set, and Treatment-Related Discontinuation = Failure is named as the primary approach to missing HIV RNA results. The primary and secondary outcome results are not reported in the registry record. Descriptive safety counts are reported across three treatment-history groups, along with selected serious-event terms. The record does not provide a randomized control comparison.