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 Raltegravir Cerebrospinal Fluid Pharmacodynamic Study in HIV-Infected Individuals (NCT01293123), a randomized na study. The primary outcome is Cerebrospinal Fluid HIV RNA Levels.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01293123 |
| Phase | NA |
| Condition | HIV |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, San Diego |
| Results posted | Yes |
2. Clinical Question
Population
People with HIV were eligible for the study. The registry record lists enrollment of 2, but does not provide further participant characteristics. The primary outcome entry states that enrollment was insufficient for data analysis.
Intervention
The study planned to assess raltegravir, an HIV integrase inhibitor, in combination with two other antiretrovirals. The description says cerebrospinal fluid (CSF) would be collected before and after treatment initiation. Details of the co-administered drugs and regimen are not reported in the registry record.
Comparator
The comparator was efavirenz, also in combination with two other antiretrovirals. The registry record does not describe the comparator regimen in further detail. Allocation was randomized, and the design was parallel and unmasked.
Primary question
The primary question was about the slope of decline in CSF HIV RNA levels over 180 days. In practical terms, the study aimed to assess how the measured viral RNA level in CSF changed over time after initiation of either treatment. The record does not report an estimated slope or an analysis comparing the treatment groups.
The study also planned neuropsychological testing and assessments of mood, sleep, and quality of life. These outcomes broadened the assessment beyond CSF HIV RNA, but no results for them are reported in the registry record. With enrollment of 2 and no primary analysis, the posted information does not establish whether the planned comparison could be estimated or how precisely any difference between groups could be assessed.
3. Trial Design
The registry record describes a randomized, parallel-group study with no masking. Participants were to receive either raltegravir or efavirenz, each in combination with two other antiretrovirals, according to the study summary. The record does not provide further detail about the treatment regimens, allocation procedures, or the timing and conduct of assessments beyond the stated primary outcome timeframe.
The planned primary assessment concerned the slope of decline in CSF HIV RNA levels over 180 days. The summary describes collecting CSF before and after initiation of treatment. It also lists neuropsychological performance, mood, sleep, and quality of life as secondary outcomes. There are five outcome measures listed overall, but the record does not provide result estimates for any of them.
The recorded enrollment was 2. The study status is terminated. Its start is listed as 2011-12 and its primary completion as 2013-06. The registry record does not state why the study was terminated, how many participants were assigned to each arm beyond the safety table’s at-risk counts, or whether all planned assessments were completed. It also does not report a sample-size justification or a statistical analysis plan. The primary outcome entry explicitly says enrollment was insufficient for data analysis, and the registry record lists no analyses.
These details matter when reading the design. Randomization describes the intended allocation method; it does not by itself ensure that a treatment comparison can be estimated from a very small enrolled group. The parallel design indicates separate treatment groups rather than a planned within-person crossover comparison. Because the study was unmasked, the record does not describe blinded treatment assignment or outcome assessment. The posted information is therefore best read as a description of the intended study question and its limited recorded enrollment, not as a completed comparative efficacy analysis.
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 | Raltegravir | Efavirenz |
|---|---|---|
| STARTED | 1 | 1 |
| COMPLETED | 1 | 0 |
| NOT COMPLETED | 0 | 1 |
Reasons for not completing this period:
| Reason | Raltegravir | Efavirenz |
|---|---|---|
| Lost to Follow-up | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Insufficient enrollment for data analysis
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 | Raltegravir | Efavirenz | Total |
|---|---|---|---|---|
| Participants analysed | 1 | 1 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 1 | 1 | 2 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 26 (SD 0) | 36 (SD 0) | 31 (SD 0) |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 1 | 1 | 2 |
| Region of Enrollment: United States | participants | 1 | 1 | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Cerebrospinal Fluid HIV RNA Levels, measured over 180 days.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is described as the slope of decline in CSF HIV RNA levels over time, with a timeframe of 180 days. HIV RNA is a measure of viral material, and CSF is the fluid surrounding the brain and spinal cord. In general, measuring CSF HIV RNA can address a question about viral levels in that compartment rather than relying only on measurements from another body compartment.
A slope summarizes the direction and rate of change across repeated measurements. In general, using a slope can make use of measurements taken at multiple times, rather than treating a single measurement as the entire outcome. It can therefore express how a measured level changes over the assessment period. The registry record does not give the planned measurement schedule, the slope model, or the rules for handling incomplete measurements, so the precise construction of the endpoint is not reported in the registry record.
The endpoint was intended to compare the change in CSF HIV RNA after initiation of raltegravir or efavirenz. However, the posted primary outcome entry says enrollment was insufficient for data analysis. No slope estimate, between-group contrast, confidence interval, or test result is reported. The endpoint description therefore states what the study set out to measure, not an observed treatment effect.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central statistical fact is that the registry record does not contain an analysis of the primary endpoint. It records enrollment of 2 and describes the primary outcome population as having insufficient enrollment for data analysis. There is consequently no reported estimate of the slope of CSF HIV RNA decline, no comparison between raltegravir and efavirenz, and no measure of uncertainty around such a comparison. The posted record does not support a conclusion about the direction or size of a treatment difference.
This is different from a result showing that the treatments had similar outcomes. A similarity conclusion would require an informative estimate and an assessment of its precision against a suitable definition of similarity. No such estimate or definition is reported. Likewise, the absence of an analysis is not evidence that there was no change in CSF HIV RNA. The registry record leaves the primary question unanswered.
Randomized allocation can reduce systematic differences between groups in a sufficiently informative study, but randomization cannot compensate for a lack of analyzable outcome information. With enrollment of 2, the recorded study is far smaller than would ordinarily be needed to make a stable comparison of a variable measured over time. The record does not report the actual allocation counts for the primary analysis, participant-level measurements, or a usable group comparison. It would be inappropriate to infer a treatment effect from the design description alone.
The secondary outcomes also require restraint. The registry lists neuropsychological performance, mood, sleep, and quality of life, but no results or analyses for these outcomes are reported. The existence of planned assessments does not show that data were collected or analyzed. No estimates, uncertainty intervals, or inferential tests are posted for these outcomes.
The displayed safety counts have a different role from the primary endpoint. They report zero serious adverse events, zero other adverse events, and zero deaths in each group, with 1 participant at risk in each group. These are small recorded counts, not a precise comparative safety analysis. They cannot establish that either treatment is free of risk, and the record gives no basis for evaluating completeness of safety ascertainment.
Any planning illustrations elsewhere on the page should also be distinguished from observed results. They are sample-size planning displays, not observed power and not evidence of a treatment effect. The registry record does not provide the primary outcome analysis needed to interpret the trial as a comparative clinical result.
9. Statistical Methods Explained
The methods described in the registry record are limited. It identifies randomized allocation, a parallel-group model, no masking, and a primary endpoint based on the slope of CSF HIV RNA decline over 180 days. It does not report a detailed statistical analysis plan. The explanations below describe general statistical concepts; they should not be read as claims about analyses actually conducted in this study.
What does a slope represent?
In general, a slope describes how an outcome changes as time passes. For an outcome measured repeatedly, an analysis can use the pattern of measurements to estimate the rate and direction of change over the period of interest. The study’s endpoint description refers to a slope of decline in CSF HIV RNA levels. It does not specify the mathematical model, time points, transformation of the RNA measurements, or whether the intended analysis would estimate a separate slope for each treatment group before comparing them. Those details are not reported in the registry record.
A slope can be useful when the scientific question concerns change over time rather than a single endpoint measurement. But its interpretation depends on how observations are collected and modeled. For example, the analysis must account appropriately for repeated observations from the same participant, since those measurements are generally related rather than independent. This is a general consideration for longitudinal data, not a description of a reported analysis in this record.
How does randomization relate to the comparison?
In general, randomization assigns participants to treatment groups using a chance-based process. Its purpose is to reduce the risk that the groups differ systematically in measured or unmeasured characteristics at the start of a study. This supports a fair comparison when enrollment and follow-up yield enough information. Randomization does not guarantee that groups will be balanced in a very small study, and it does not create information when outcome data are too limited to analyze.
The parallel-group description means that the study was organized around separate groups receiving the two interventions. The record says allocation was randomized and masking was none. It does not describe the randomization sequence, concealment procedures, or whether outcome assessors were masked. These procedural details are not reported in the registry record.
What would uncertainty measures tell a reader?
In general, a confidence interval gives a range of values compatible with the data and the statistical method used, while reflecting sampling uncertainty. A narrow interval indicates greater precision than a wide interval, though interpretation also depends on the outcome and the question being asked. A p-value, when reported, summarizes how compatible the observed data are with a specified null hypothesis under the assumptions of the test; it is not the probability that a treatment works or that the null hypothesis is true.
For this study, no primary estimate, confidence interval, or p-value is reported in the registry record. The record’s statement that enrollment was insufficient for data analysis means that these usual tools for interpreting a treatment contrast are unavailable. It would not be appropriate to create or infer them from the trial design or safety counts.
What can sample-size planning show?
In general, sample-size planning asks how many participants would be needed to estimate an effect or detect a specified effect under stated assumptions. The planning displays are illustrations, not observed power and not a reconstruction of the trial’s own design. The stated assumptions include a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Such displays depend on the effect-size assumptions used and should not be mistaken for outcomes observed in the study.
The registry record does not report a sample-size justification for the trial itself. It also does not report an observed effect estimate for the primary endpoint. Consequently, the planning displays cannot fill the gap left by the absence of an analysis or establish what the study would have found with a different enrollment.
What does the absence of an analysis imply?
It means that the posted record does not provide a statistical estimate for the primary comparison. It does not mean that a statistical test found no difference, or that the outcomes were equal. The record lists zero analyses and explicitly characterizes the primary outcome population as insufficient for data analysis. No model, adjustment strategy, handling of missing measurements, or prespecified testing hierarchy is reported in the registry record.
When interpreting any trial report, it is generally useful to distinguish the design, the collected data, and the analysis. A randomized design describes how treatment assignment was intended to occur. An endpoint describes what outcome was intended for evaluation. Neither is a substitute for a reported analysis. Here, the posted information identifies the question and design, but not an analyzable comparative result.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one primary outcome, the slope of decline in CSF HIV RNA levels over 180 days, and secondary outcomes covering neuropsychological performance, mood, sleep, and quality of life. It lists five outcome measures overall. The record does not describe how many statistical tests were planned, whether each secondary outcome had multiple measures or time points, or how testing across outcomes was to be handled.
In general, multiplicity arises when several hypotheses or outcomes are tested. The more comparisons considered, the greater the chance that at least one result may appear unusual by chance if the tests are interpreted without accounting for their number. Statistical plans can address this in different ways, but the registry record does not report a multiplicity strategy or a hierarchy for interpreting the outcomes. Because no analyses are reported, there are no posted test results to interpret in light of that issue.
Missing-data methods and analysis populations are also not described. The registry record does not say how incomplete CSF measurements, missed visits, or unavailable secondary assessments would have been handled. It does not identify an intention-to-treat, per-protocol, or other analysis population for the primary endpoint. The primary outcome entry says enrollment was insufficient for data analysis, but this does not explain which data were collected or why analysis was not possible. These details are not reported in the registry record, so the reader cannot assess the impact of missing data or determine which participants would have contributed to a planned 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 |
|---|---|---|---|
| Raltegravir | 0 | 1 | 0.0% |
| Efavirenz | 0 | 1 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Raltegravir | 0 of 1 |
| Efavirenz | 0 of 1 |
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 |
|---|---|
| Raltegravir | 0 of 1 |
| Efavirenz | 0 of 1 |
The registry’s safety table records 1 participant at risk in each group. For the raltegravir group, it reports zero serious adverse events, zero other adverse events, and zero deaths. For the efavirenz group, it also reports zero serious adverse events, zero other adverse events, and zero deaths.
These counts should be read in the context of the very small recorded at-risk groups. A zero count in a group of this size does not establish that an event cannot occur, nor does it provide a precise comparison of safety between treatments. It also does not show how completely or for how long adverse events were monitored. The registry record does not report event definitions, monitoring procedures, or additional safety analyses. The table is a report of the posted counts, not a basis for concluding that either treatment has no safety risks.
12. What the Result Does, and Does Not, Mean
The result available from this registry record is primarily a statement about the limits of the evidence: the study enrolled 2, and the primary outcome entry says enrollment was insufficient for data analysis. Although the record describes an intended randomized comparison of raltegravir and efavirenz, it does not report a primary endpoint estimate or an analysis comparing the groups.
Accordingly, the record does not show whether CSF HIV RNA levels declined, how quickly they changed, or whether the slopes differed between the interventions. It also does not show whether neuropsychological performance, mood, sleep, or quality of life changed. No treatment-effect estimate or precision measure is posted for these outcomes. The absence of such results is not a finding of no effect, no change, or equivalence.
The safety table reports zero serious adverse events, zero other adverse events, and zero deaths in each group, with 1 participant at risk per group. These figures describe the counts entered in the registry. They are too limited to support broad conclusions about comparative safety or the likelihood of uncommon events, and the record does not explain the monitoring or reporting process.
In general, a clinical trial result is most informative when readers can assess an effect estimate, its uncertainty, the analysis population, and the methods used. Those elements are not available. The study’s design and endpoint explain what it set out to investigate, while the recorded enrollment and lack of analysis explain why its posted results do not answer the treatment comparison. Planning displays on the page should be viewed as sample-size illustrations, not as observed evidence or a substitute for trial results.
13. Why This Trial Matters Statistically
This record is statistically instructive because it separates a well-defined research question from evidence that can answer it. The study planned a randomized comparison and specified a biologically focused endpoint: change in CSF HIV RNA over 180 days. But a design and an endpoint do not produce a treatment estimate on their own. The registry record reports enrollment of 2 and states that the primary outcome could not be analyzed because enrollment was insufficient.
That distinction is important for readers of clinical research. A study can be designed to reduce bias through randomization and still fail to provide an informative comparison if too little analyzable information is available. Without an estimate and an uncertainty interval, readers cannot judge whether the data are compatible with a meaningful benefit, little difference, or a difference in the other direction. A missing analysis should not be mistaken for a negative finding.
The record also illustrates why outcome and safety counts need context. The listed secondary outcomes suggest several domains of interest, but the registry does not report analyses for them or a plan for handling multiple outcomes. The safety table shows no events in the small recorded at-risk groups, but these counts do not establish absence of risk. Interpreting either set of outcomes requires attention to the amount and completeness of information, not only to the labels of the outcomes.
Finally, the case shows the limits of planning illustrations. Sample-size calculations can clarify how assumptions relate to a desired study size, but they are not observed power and cannot recover a treatment effect that the posted record does not estimate. The main statistical lesson is that design, analysis, and interpretation are distinct stages, and the registry record documents only a limited basis for the final stage.
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 direct limitation is the recorded enrollment of 2 and the registry’s statement that there was insufficient enrollment for primary outcome data analysis. The record lists no analyses, so it provides no estimate for the primary endpoint or the secondary outcomes. This prevents assessment of effect size and precision.
Important design and analysis details are also absent. The record does not report the sample-size justification, detailed treatment regimens, allocation procedures, measurement schedule, statistical model, analysis populations, missing-data approach, or any multiplicity strategy. It does not state why the study was terminated. These items are not reported in the registry record, and their absence limits assessment of how the study was conducted and what data may have been available.
The unmasked design is recorded, but the registry does not say whether outcome assessment was masked. The planned outcomes include CSF HIV RNA and several assessment domains, yet no results are posted for them. The safety table has 1 participant at risk per group and reports no events, but does not describe event monitoring or ascertainment. These limitations mean that neither efficacy nor safety can be evaluated with precision from the posted results.
The record is therefore useful for identifying the intended question, design, and reason the primary result is unavailable, but it cannot support a comparative clinical conclusion. Any planning displays elsewhere on the page remain illustrations rather than a remedy for the missing analysis.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Raltegravir Cerebrospinal Fluid Pharmacodynamic Study in HIV-Infected Individuals — NCT01293123.
- Registry record last updated 2019-10-31; status last verified 2019-10.
- Results first posted 2019-10-31.
- 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
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a randomized, parallel, unmasked study comparing raltegravir with efavirenz in people with HIV. Both treatments were described as being used with two other antiretrovirals. The primary outcome was the slope of decline in CSF HIV RNA levels over 180 days; secondary outcomes covered neuropsychological performance, mood, sleep, and quality of life.
Enrollment was 2, and the study status is terminated. The primary outcome entry states that enrollment was insufficient for data analysis, and the registry lists no analyses. No comparative outcome estimates are reported. The safety table records 1 participant at risk in each group, with zero serious adverse events, zero other adverse events, and zero deaths in both groups. These limited counts do not establish comparative safety.