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 Vicriviroc (SCH 417690) in Combination Treatment With Optimized ART Regimen in Experienced Participants (VICTOR-E1) (MK-7690-020/P03672) (NCT00243230), a randomized phase 2 study. The primary outcome is Change From Baseline in Log10 Human Immunodeficiency Virus (HIV) Ribonucleic Acid (RNA) at Week 48 of the Double-blind Period.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00243230 |
| Phase | Phase 2 |
| Condition | HIV Infections |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 116 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
The trial enrolled participants with CCR5-tropic HIV infection who were not responding adequately to a standard antiretroviral therapy regimen. The analysis population for the primary endpoint included randomized participants who received at least one dose of study medication during the double-blind period. Participants enrolled in the open-label period were excluded from that primary analysis population. The registry reports enrollment of 116 participants overall; it does not give the primary endpoint analysis population size in this record.
Intervention
The randomized double-blind treatment groups received vicriviroc 30 mg or vicriviroc 20 mg once daily by mouth, each alongside an open-label optimized antiretroviral therapy regimen containing a ritonavir-boosted protease inhibitor. Treatment in the double-blind period was described for 48 weeks. The record also describes an open-label group receiving vicriviroc 30 mg with optimized therapy for up to 45 months.
Comparator
The double-blind comparator was placebo once daily by mouth, alongside an open-label optimized antiretroviral therapy regimen containing a ritonavir-boosted protease inhibitor. The registry describes a randomized, parallel-group trial with triple masking. It does not report the number allocated to each randomized treatment group in the record.
Primary question
The primary question was whether adding either vicriviroc dose to optimized therapy changed HIV RNA from baseline to Week 48 of the double-blind period, relative to placebo with optimized therapy. HIV RNA was measured in log10 copies/mL, and the endpoint was the mean change from baseline. The registry describes an analysis adjusted for treatment and stratification factors, but does not report the group estimates, the between-group contrasts, confidence intervals, or p values. Therefore, the record supports describing the question and planned endpoint, but not the direction, magnitude, or precision of the primary result.
3. Trial Design
This was a randomized, parallel-group Phase 2 trial of vicriviroc in combination with optimized antiretroviral therapy. The registry describes triple masking and enrollment of 116 participants. The study is marked completed; its recorded start date is 2005-09-19 and its primary completion date is 2007-10-19. These dates describe the trial record and do not, by themselves, convey when individual participants began or ended treatment.
During the double-blind period, participants were assigned to vicriviroc 30 mg, vicriviroc 20 mg, or placebo, each taken once daily by mouth with an open-label optimized antiretroviral therapy regimen containing a ritonavir-boosted protease inhibitor. The primary endpoint was assessed at Week 48. The study summary describes the objective as evaluating the antiviral efficacy of two vicriviroc doses compared with placebo when used with that background regimen in participants with CCR5-tropic HIV infection who were failing a standard regimen.
The record also describes an open-label period in which vicriviroc 30 mg was taken with optimized therapy for up to 45 months. Participants enrolled in the open-label period were not part of the primary endpoint analysis population. The registry lists 25 outcome measures and 26 analyses, including secondary measures involving HIV RNA, time to loss of virologic response, and CD4 cell counts at several time points.
Although the registry labels the trial randomized and triple-masked, it does not report the randomization sequence, allocation concealment procedures, or which roles were masked. It also does not report the planned sample-size justification or detailed operational procedures for the trial.
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.
Double-Blind Period
| Stage | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|
| STARTED | 39 | 40 | 37 | 0 |
| Treated | 39 | 40 | 35 | 0 |
| COMPLETED | 33 | 35 | 18 | 0 |
| NOT COMPLETED | 6 | 5 | 19 | 0 |
Reasons for not completing this period:
| Reason | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|
| Adverse Event | 0 | 2 | 2 | 0 |
| Withdrawal by Subject | 1 | 0 | 0 | 0 |
| Protocol Violation | 0 | 0 | 1 | 0 |
| Randomized but Not Treated | 0 | 0 | 2 | 0 |
| Treatment Failure - Virologic Failure defined by investigator | 5 | 3 | 14 | 0 |
Open Label Period
| Stage | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|
| STARTED | 0 | 0 | 0 | 85 |
| COMPLETED | 0 | 0 | 0 | 0 |
| NOT COMPLETED | 0 | 0 | 0 | 85 |
Reasons for not completing this period:
| Reason | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|
| Adverse Event | 0 | 0 | 0 | 2 |
| Treatment Failure - Virologic Failure | 0 | 0 | 0 | 13 |
| Progressive Disease (AIDS-Event) | 0 | 0 | 0 | 1 |
| Lost to Follow-up | 0 | 0 | 0 | 2 |
| Withdrawal by Subject | 0 | 0 | 0 | 2 |
| Protocol Violation | 0 | 0 | 0 | 2 |
| Administrative Reason | 0 | 0 | 0 | 63 |
Analysis population for the primary outcome, as defined in the registry: The analysis population included all randomized participants who received at least 1 dose of study medication during the Double-blind Period. Participants enrolled in the Open Label Period were not included in this analysis population.
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 analysis population included all randomized participants.
| Characteristic | Unit | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Total |
|---|---|---|---|---|---|
| Participants analysed | 39 | 40 | 37 | 116 | |
| Age, Continuous | Years | 44.9 (SD 7.3) | 44.0 (SD 8.0) | 45.5 (SD 8.8) | 44.8 (SD 8.0) |
| Sex: Female, Male: Female | Participants | 6 | 9 | 11 | 26 |
| Sex: Female, Male: Male | Participants | 33 | 31 | 26 | 90 |
| Race/Ethnicity, Customized: White | Participants | 26 | 32 | 21 | 79 |
| Race/Ethnicity, Customized: Black | Participants | 9 | 3 | 8 | 20 |
| Race/Ethnicity, Customized: Asian | Participants | 0 | 1 | 0 | 1 |
| Race/Ethnicity, Customized: Other | Participants | 4 | 4 | 8 | 16 |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Log10 Human Immunodeficiency Virus (HIV) Ribonucleic Acid (RNA) at Week 48 of the Double-blind Period, measured over Baseline and Week 48 of the Double-blind Period.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | Log10 copies/mL |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was change from baseline in log10 HIV RNA at Week 48 of the double-blind period, measured in log10 copies/mL. HIV RNA is a measure of the amount of virus detected in blood. Expressing the measure on a log10 scale allows changes to be represented on a scale suited to values that can span a broad range. The endpoint was summarized as a mean, with standard deviation as the reported measure of dispersion.
The endpoint addresses whether viral load changed during treatment and whether the average change differed across the randomized treatment groups. General statistical context: a mean gives a group-level summary, while a standard deviation describes variability among individual observations around that mean. Neither alone communicates how precisely a treatment-group contrast is estimated; that usually requires an uncertainty measure such as a confidence interval.
The registry specifies an assay process. HIV RNA was measured with the AMPLICOR HIV-1 MONITOR Standard assay; when results were below its lower quantification level of 400 copies/mL, the AMPLICOR HIV-1.5 UltraSensitive assay was used. A value of 49 was imputed when a result was below the UltraSensitive assay lower quantification level of 50 copies/mL. The registry record does not report the primary group means, standard deviations, or treatment contrasts, so the observed size and precision of change cannot be described from this record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The clinical question focused on average change in HIV RNA over the double-blind period, comparing each vicriviroc dose with placebo while all groups received optimized antiretroviral therapy. The endpoint and adjusted analysis are described in the registry record. However, the primary results themselves are not reported in the record: there are no group-level mean changes, between-group estimates, confidence intervals, or p values available in the registry record for this analysis. Consequently, the statistical evidence about the primary question cannot be characterized as favoring one group, showing little difference, or being inconclusive.
That absence matters for interpretation. A treatment contrast gives the estimated difference between groups; its sign and size indicate the direction and magnitude on the endpoint scale. A confidence interval communicates the range of values compatible with the data under the analysis assumptions, and helps distinguish a precisely estimated small contrast from a less precise estimate. A p value addresses compatibility with a specified null hypothesis under a statistical model, but does not itself describe the size or clinical importance of an effect. None of these numerical results is reported for the primary endpoint in this registry record.
The primary analysis was described as an analysis of variance model adjusted for treatment and two stratification factors: intended enfuvirtide use in the newly optimized background regimen and HIV RNA category at screening. This indicates that the reported analysis was not simply an unadjusted comparison of group means. The registry does not give the model coefficients, adjusted means, model diagnostics, or other details needed to assess the fitted analysis beyond the stated description.
The primary analysis population was restricted to randomized participants who received at least one dose during the double-blind period. It excluded participants enrolled in the open-label period. This population definition is important when interpreting any estimate because it specifies which participants contributed to the primary analysis. The number included in that analysis and the number with observed Week 48 measurements are not reported in the registry record.
Secondary outcomes listed in the record include thresholds of HIV RNA change and suppression, time to loss of virologic response, and CD4 count changes at multiple time points. Their presence shows that the study examined more than one outcome, but the record does not provide their estimates in the registry record for this analysis. No conclusion about those outcomes, or about consistency between primary and secondary findings, can be drawn from the endpoint descriptions alone.
The adverse-event summaries provide counts for participants at risk and with serious or other adverse events in the listed groups, along with death counts. These are descriptive safety data, not substitutes for the missing primary efficacy estimates. Because group exposure periods differ between the double-blind and open-label descriptions, those counts should be read in their stated group and period context rather than treated as a direct estimate of comparative treatment effect.
9. Statistical Methods Explained
What does the adjusted mean comparison represent?
The registry describes an analysis of variance model for the primary endpoint. In general, analysis of variance models compare means across groups while accounting for specified explanatory factors. Here, the stated model adjusted for treatment and for the intended use of enfuvirtide in the newly optimized background regimen, as well as HIV RNA category at screening. Those factors are the ones named in the registry description; further model terms or implementation details are not reported in the registry record.
Adjustment can account for the categories included in the model when estimating group differences. It does not guarantee that all possible differences between participants are removed, nor does it make the estimate free of assumptions. General statistical context: model-based estimates depend on the model specification and on the adequacy of its assumptions for the data. The registry record does not report diagnostics or a detailed assessment of those assumptions. It also does not report the adjusted group estimates or contrasts, so the effect magnitude and its uncertainty cannot be interpreted from this description alone.
What is the role of the analysis population?
The primary analysis population included all randomized participants who received at least one dose of study medication during the double-blind period. Participants enrolled in the open-label period were not included. This is a specific analysis population definition and should not be conflated with every participant enrolled in the trial. The registry does not state the count in this population or the count with available Week 48 data.
General statistical context: an analysis population determines which participants contribute to an estimate and can affect how results relate to the original randomization. An analysis restricted by receipt of treatment is not identical to an analysis of everyone randomized, because inclusion depends on a post-randomization event. The registry description does not provide enough detail to determine the consequences of that restriction, or whether other analysis populations were also used for the primary outcome.
How were values below assay limits handled?
The registry describes a two-stage measurement approach. The Standard assay was used to measure HIV RNA. For results below its lower quantification level of 400 copies/mL, the UltraSensitive assay was performed. When a result was below that assay’s lower quantification level of 50 copies/mL, the value 49 was imputed. This is a rule for assigning a numeric value to a measurement below the assay’s stated quantification limit; it is not a directly measured value at that level.
General statistical context: measurements below a detection or quantification limit contain less precise information about the underlying value than a quantified measurement. Replacing such values with a fixed number can influence summary statistics and model estimates, particularly if many observations are affected. The registry record does not report how many values were below either limit or whether alternative handling was examined, so the impact of this rule cannot be assessed from the description.
How were missing Week 48 values handled?
For a continuing participant with a missing HIV RNA value at the time point of interest, the geometric mean of the immediately preceding and following values was used. If there was no subsequent following value, or if the participant discontinued study treatment before the time point of interest, the change from baseline was set to zero. These rules distinguish between a missing value for a continuing participant with measurements on either side and a missing value associated with no following measurement or treatment discontinuation.
General statistical context: imputation substitutes an assigned value for a missing observation so that an analysis can proceed, but the assigned value is not the participant’s observed outcome at that time. The validity of an imputation strategy depends on assumptions about why values are missing and how the unobserved outcomes relate to observed information. The registry record states the rules but does not report the amount or pattern of missingness, or sensitivity analyses examining the effect of alternative assumptions.
How should planning calculations be understood?
General statistical context: a sample-size calculation is a planning exercise, not a finding about participants who took part. The registry record states that the planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect expressed as a fraction of the observed effect. It also specifies that time-to-event illustrations use a total event count, while other illustrations use participants per arm.
These planning assumptions do not establish the trial’s original design justification. That justification is not reported in the registry record. An illustration based on an observed effect also depends on the size of that effect; the registry record does not report the primary effect estimate needed to interpret a numerical illustration. Planning sample sizes should not be read as observed power or as evidence that the trial was adequately powered. The record does not report the original target sample size or a sample-size justification.
For the primary endpoint, the registry entries describe an adjusted model but do not include a confidence interval or p value. General statistical context: a confidence interval expresses uncertainty around an estimate, while a p value evaluates data compatibility with a specified null model. Neither can be reconstructed from the endpoint definition and method description alone. The registry record also does not report whether interim analyses were planned or conducted, or a detailed statistical analysis plan.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 25 outcome measures and 26 analyses. The primary outcome is change from baseline in log10 HIV RNA at Week 48 of the double-blind period. Listed secondary outcomes include participants with at least a 1.0 log10 change from baseline in HIV RNA, participants with HIV RNA below 400 copies/mL, time to loss of virologic response, and changes in HIV RNA or CD4 count at earlier and later time points.
When a study evaluates multiple outcomes or time points, the chance of observing a nominally unusual result somewhere among the analyses can be greater than for one prespecified comparison. General statistical context: multiplicity procedures can address this issue by controlling an error rate or by structuring which findings are confirmatory and which are exploratory. The registry record does not report whether multiplicity adjustments were planned or applied, nor does it describe a hierarchy among the secondary outcomes. The interpretation of any secondary p values therefore cannot be assessed from the registry description alone.
The record gives explicit rules for some missing HIV RNA measurements: geometric-mean imputation for a continuing participant with immediately preceding and following measurements, and a change-from-baseline value of zero when there is no following value or treatment was discontinued before the time point. It also gives the below-quantification handling for the assays. The number of participants affected by these rules and the overall extent of missing data are not reported in the registry record.
The primary analysis population comprised randomized participants who received at least one dose during the double-blind period; open-label participants were excluded. The record does not report the size of this population, the number included in each endpoint analysis, or whether other analysis populations were used. It also does not report sensitivity analyses for missing data, the original sample-size justification, or interim analyses. These omissions limit assessment of the robustness and multiplicity context of the stated analysis.
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 |
|---|---|---|---|
| Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | 4 | 39 | 10.3% |
| Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | 5 | 40 | 12.5% |
| Double-Blind Period - Placebo Plus an ART Regimen | 5 | 35 | 14.3% |
| Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen | 13 | 85 | 15.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | 0 of 39 |
| Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | 2 of 40 |
| Double-Blind Period - Placebo Plus an ART Regimen | 2 of 37 |
| Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen | 1 of 85 |
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 |
|---|---|
| Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | 34 of 39 |
| Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | 31 of 40 |
| Double-Blind Period - Placebo Plus an ART Regimen | 29 of 35 |
| Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen | 58 of 85 |
Most frequent serious adverse event terms
| Event term | Organ system | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|---|
| ANAEMIA | Blood and lymphatic system disorders | 0 of 39 | 0 of 40 | 2 of 35 | 0 of 85 |
| LYMPHADENOPATHY | Blood and lymphatic system disorders | 0 of 39 | 1 of 40 | 0 of 35 | 1 of 85 |
| CHEST PAIN | General disorders | 0 of 39 | 0 of 40 | 1 of 35 | 1 of 85 |
| DEHYDRATION | Metabolism and nutrition disorders | 2 of 39 | 0 of 40 | 0 of 35 | 0 of 85 |
| FEMUR FRACTURE | Injury, poisoning and procedural complications | 0 of 39 | 0 of 40 | 0 of 35 | 2 of 85 |
| COAGULOPATHY | Blood and lymphatic system disorders | 0 of 39 | 1 of 40 | 0 of 35 | 0 of 85 |
| ACUTE CORONARY SYNDROME | Cardiac disorders | 0 of 39 | 1 of 40 | 0 of 35 | 0 of 85 |
| CARDIOPULMONARY FAILURE | Cardiac disorders | 0 of 39 | 0 of 40 | 1 of 35 | 0 of 85 |
| PERICARDITIS URAEMIC | Cardiac disorders | 1 of 39 | 0 of 40 | 0 of 35 | 0 of 85 |
| ABDOMINAL PAIN | Gastrointestinal disorders | 0 of 39 | 1 of 40 | 0 of 35 | 0 of 85 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Double-Blind Period - Vicriviroc 30 mg Plus an ART Regimen | Double-Blind Period - Vicriviroc 20 mg Plus an ART Regimen | Double-Blind Period - Placebo Plus an ART Regimen | Open-Label Period - Vicriviroc 30 mg Plus an ART Regimen |
|---|---|---|---|---|---|
| DIARRHOEA | Gastrointestinal disorders | 15 of 39 | 11 of 40 | 9 of 35 | 9 of 85 |
| HEADACHE | Nervous system disorders | 5 of 39 | 3 of 40 | 7 of 35 | 7 of 85 |
| PYREXIA | General disorders | 4 of 39 | 4 of 40 | 4 of 35 | 6 of 85 |
| SINUSITIS | Infections and infestations | 2 of 39 | 4 of 40 | 2 of 35 | 10 of 85 |
| INFLUENZA | Infections and infestations | 3 of 39 | 5 of 40 | 1 of 35 | 8 of 85 |
| DEPRESSION | Psychiatric disorders | 3 of 39 | 4 of 40 | 6 of 35 | 3 of 85 |
| COUGH | Respiratory, thoracic and mediastinal disorders | 2 of 39 | 5 of 40 | 2 of 35 | 7 of 85 |
| NAUSEA | Gastrointestinal disorders | 5 of 39 | 3 of 40 | 5 of 35 | 2 of 85 |
| UPPER RESPIRATORY TRACT INFECTION | Infections and infestations | 2 of 39 | 2 of 40 | 0 of 35 | 11 of 85 |
| FATIGUE | General disorders | 2 of 39 | 5 of 40 | 3 of 35 | 3 of 85 |
Serious events with the highest arm-level rate: anaemia (5.7%), dehydration (5.1%), cardiopulmonary failure (2.9%), diarrhoea (2.9%), chest pain (2.9%).
The serious adverse-event summaries give, for each listed group, the number of participants at risk and the number affected. In the double-blind period, the vicriviroc 30 mg group had 4 of 39 participants affected, the vicriviroc 20 mg group had 5 of 40, and the placebo group had 5 of 35. The open-label vicriviroc 30 mg group had 13 of 85 participants affected. The record lists deaths of 0, 2, 2, and 1, respectively, for those groups.
These are counts within the listed groups, not adjusted comparisons. The double-blind groups are described over 48 weeks, while the open-label vicriviroc 30 mg regimen is described for up to 45 months. The different periods and group descriptions mean the open-label count should not be read as a direct randomized comparison with the double-blind groups. The registry record does not provide further exposure-adjusted analyses in the registry record.
The registry also lists serious-event terms with percentages: anaemia, 5.7%; dehydration, 5.1%; cardiopulmonary failure, 2.9%; diarrhoea, 2.9%; chest pain, 2.9%; and gastroenteritis escherichia coli, 2.9%. The record does not specify the denominator or group context for these listed term figures in the registry record for this account. These summaries describe reported events; they do not establish that a treatment caused an event or permit a comparative causal conclusion.
12. What the Result Does, and Does Not, Mean
The registry record identifies the question the trial set out to address: whether either of two vicriviroc doses, added to optimized antiretroviral therapy, changed HIV RNA at Week 48 compared with placebo added to the same type of background regimen. It also describes the endpoint scale, the primary analysis population, adjustment factors, assay procedures, and rules for some missing or below-quantification measurements. These details make the intended outcome and some of the analysis choices clear.
They do not reveal the primary result. No treatment-group mean changes, treatment contrasts, confidence intervals, or p values are reported in the registry record for the primary endpoint. Without those values, the direction and magnitude of the estimated differences and their precision cannot be described. The endpoint description alone cannot show whether results were similar across groups or whether one group had a larger average change.
General statistical context: a statistically significant result, if reported, would not by itself establish that an effect is large or important. Conversely, a result that is not statistically significant would not by itself establish that groups are equivalent. Those interpretations require effect estimates and uncertainty, together with the study question and analysis. No such primary outcome estimates are available in the registry record.
The secondary outcome list and adverse-event counts add information about what was assessed and which events were recorded, but they do not fill the gap in the primary efficacy results. The safety counts are descriptive, and the open-label group has a different treatment-period description from the double-blind groups. The record does not give the details needed to make a direct causal comparison from those counts.
Accordingly, the documented methods can be described, but a statistical conclusion about the primary treatment contrast cannot be drawn from these registry entries. The record also does not report the original sample-size justification, the multiplicity approach, or sensitivity analyses for missing data. Those are distinct limitations from the absence of outcome estimates and affect how fully the analysis can be appraised.
13. Why This Trial Matters Statistically
This trial illustrates why a clinical trial record must be read as more than a list of endpoints and methods. The registry identifies a randomized, triple-masked, parallel-group Phase 2 comparison, specifies the treatment groups, and defines a continuous primary endpoint. It also states that the primary analysis adjusted for treatment and stratification factors. These details allow the statistical question and broad analysis framework to be described without treating the method label as a result.
The record also shows how measurement and missing-data rules are part of endpoint interpretation. Below-quantification results were handled with a second assay and a specified imputed value if the result remained below its limit. Missing Week 48 values were handled differently according to whether a continuing participant had measurements on both sides of the missing time point, or whether there was no following value or treatment had been discontinued. Such rules influence which values enter a summary and should be considered when interpreting an estimate.
At the same time, the record does not report the primary estimates or their uncertainty. That distinction is statistically important: a clearly stated endpoint and model do not tell a reader how large the observed group differences were or how precisely they were estimated. The listed secondary outcomes and safety counts likewise cannot substitute for a missing primary treatment contrast.
The registry reports multiple outcomes and analyses but does not describe a multiplicity strategy. It also does not report the original sample-size justification or sensitivity analyses for missing data. These gaps illustrate why interpretation depends on both the outcome results and the context in which analyses were planned and conducted, not simply on whether a trial is randomized or masked.
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 main limitation for interpreting efficacy from this registry record is that it does not report the primary outcome estimates. Group means, standard deviations, between-group contrasts, confidence intervals, and p values are absent in the registry record described. The analysis methods can therefore be outlined, but the magnitude, direction, and precision of the primary comparison cannot be assessed.
The primary analysis population is defined as randomized participants who received at least one dose during the double-blind period, with open-label participants excluded. The record does not give the number analyzed or the number with measured Week 48 outcomes. It also does not report the extent or pattern of missing data, or sensitivity analyses to assess the consequences of the stated imputation rules.
The endpoint description gives assay procedures and a fixed imputation rule for results below the UltraSensitive assay limit. It does not report how many measurements required this handling or whether other approaches were evaluated. Without those details, the influence of below-limit values and missing-data decisions cannot be quantified.
The record lists multiple outcomes and analyses but does not report whether multiplicity was addressed. It also does not report an original sample-size justification, the detailed statistical analysis plan, or whether interim analyses were planned or conducted. Randomization and triple masking are stated, but the allocation procedures and masking roles are not described in the registry record.
Finally, the safety summaries include double-blind and open-label groups with different described periods of treatment. The term-specific serious-event percentages are not accompanied by denominator or group context in the registry record used. These limits preclude treating the descriptive counts as a direct comparison of treatment-related risk.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Vicriviroc (SCH 417690) in Combination Treatment With Optimized ART Regimen in Experienced Participants (VICTOR-E1) (MK-7690-020/P03672) — NCT00243230.
- Registry record last updated 2021-06-08; status last verified 2021-05.
- Results first posted 2021-06-08.
- 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 registry record describes NCT00243230, a completed, randomized, triple-masked, parallel-group Phase 2 trial with enrollment of 116 participants. The study evaluated vicriviroc 30 mg and 20 mg against placebo, each with an optimized antiretroviral therapy regimen containing a ritonavir-boosted protease inhibitor, in participants with CCR5-tropic HIV infection who were not responding adequately to standard treatment.
The primary endpoint was mean change from baseline in log10 HIV RNA at Week 48 of the double-blind period. The primary analysis was described as an analysis of variance model adjusted for treatment and stratification factors. The record also specifies assay and missing-data handling rules and lists secondary outcome measures.
Primary endpoint estimates and uncertainty measures are not reported in the registry record. Serious adverse-event and death counts are listed for double-blind and open-label groups, with the open-label regimen described for up to 45 months. The original sample-size justification, multiplicity approach, and sensitivity analyses are not reported in the record.