Evaluating the Safety and Efficacy of the VRC01 Antibody in Reducing Acquisition of HIV-1 Infection in Women: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating the Safety and Efficacy of the VRC01 Antibody in Reducing Acquisition of HIV-1 Infection in Women (NCT02568215), a randomized phase 2 study. The primary outcome is Number of Participants Reporting Local Reactogenicity Signs and Symptoms: Pain and/or Tenderness.

2. Clinical Question

The endpoint is about local reactogenicity, not HIV infection itself. The distinction matters: the primary endpoint description supports a reading of how local symptoms were to be counted, while it does not answer the stated prevention question. The record describes the maximum grade observed for each symptom over the specified assessment period, but does not give the actual primary-endpoint results or a single summarized comparison. As a result, the available figures support discussion of posted safety counts, not a conclusion about whether VRC01 reduced HIV-1 acquisition.

3. Trial Design

The registry describes a randomized, parallel-group phase 2b study of VRC01 and placebo. Its official title identifies women in sub-Saharan Africa and frames the study around safety and efficacy in reducing HIV-1 infection acquisition. The listed condition is HIV infections. The record lists enrollment of 1924, a start date of 2016-05, primary completion on 2021-03-03, and status as completed.

There are three assigned groups: low-dose VRC01, high-dose VRC01, and placebo. The VRC01 arms used intravenous infusions of 10 mg/kg or 30 mg/kg. Each regimen was scheduled at Weeks 0, 8, 16, 24, 32, 40, 48, 56, 64, and 72, with each infusion described as taking about 30 to 60 minutes. The placebo arm is also described as receiving infusions over about 30 to 60 minutes at those weeks. The record lists quadruple masking, but does not specify in the available information which roles were masked or how masking was maintained.

The posted safety information gives separate entries for placebo, low-dose VRC01, high-dose VRC01, and pooled VRC01. The pooled entry is a reported category, not a substitute for the two dose-specific entries. Secondary outcomes include serum VRC01 concentration and neutralization measures involving founder viruses. The registry lists 15 outcome measures and 6 analyses. Those counts describe the scope of the record, but do not reveal the full analysis plan or the findings for each outcome.

Although the study is marked completed, the information does not include the primary endpoint’s observed result, an HIV-acquisition comparison, or inferential statistics for those outcomes. Completion status alone does not supply those missing results.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Participants were randomly assigned to the placebo, low-dose VRC01, or high-dose VRC01 arm. The pooled VRC01 arm represents participants assigned to low-dose or high-dose VRC01 and is the primary comparison group for the primary analysis of prevention efficacy.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety 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: Safety Population

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Reporting Local Reactogenicity Signs and Symptoms: Pain and/or Tenderness, measured over Measured through 3 days after each infusion at Weeks 0, 8, 16, 24, 32, 40, 48, 56, 64, 72..

The primary endpoint is the number of participants reporting local pain and/or tenderness. It is recorded in participants and belongs to the safety population. The registry says the symptoms were graded using the Division of AIDS Table for Grading the Severity of Adult and Pediatric Adverse Events, Version 2.1 [July 2017]. It presents the maximum grade observed for each symptom over the assessment period.

Assessment was specified through 3 days after each infusion at Weeks 0, 8, 16, 24, 32, 40, 48, 56, 64, 72. The endpoint therefore concerns symptoms associated in time with infusion visits, rather than HIV infection acquisition. The registry record does not report the observed endpoint counts or a single comparison for this measure. It also does not report a numerical estimate of the difference between groups for pain or tenderness.

In general, a local-reactogenicity endpoint can describe the frequency and severity of symptoms occurring near an administration. Grading adds information about severity that a simple yes-or-no symptom count would not capture. Repeated assessments can also characterize symptoms across a course of infusions. However, a summary based on the maximum grade does not by itself show when a symptom occurred, how long it lasted, or whether the same participant reported it at multiple visits. Those details are not reported in the registry record available for this analysis.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the design as randomized, parallel-group, and quadruple-masked. Random allocation is intended, in general, to reduce systematic differences between assigned groups at the outset. A parallel design follows assigned groups under their respective regimens rather than having each participant receive every intervention. Masking can reduce the influence of expectations on care, reporting, and assessment, but the available record does not specify who was masked or the procedures used to preserve masking.

What does the primary endpoint count?

The primary endpoint is a count of participants reporting pain and/or tenderness at the infusion site, with grading according to the cited DAIDS table. The record says the maximum grade for each symptom over the assessment window is presented. This is a participant-count endpoint, rather than a measurement expressed as a continuous quantity. The registry lists assessment through 3 days after each infusion at Weeks 0, 8, 16, 24, 32, 40, 48, 56, 64, 72. It does not report the observed primary-endpoint counts in the information, nor does it state how missing symptom assessments were handled.

Why does the record not give one primary comparison?

The registry explicitly notes that the primary outcome has several categories or time points and is not reduced to one comparison. That makes a single effect estimate inappropriate to infer from the endpoint title alone. A reader would need the relevant outcome results, the planned contrast, and its analysis method to interpret a comparison. The statistical plan, model specification, and any adjustment for repeated assessments are not reported in the registry record available for this analysis.

In general, repeated measurements from the same participant are related rather than independent. A method that accounts for this dependence can produce more appropriate uncertainty estimates than treating each observation as unrelated. Likewise, a maximum-grade summary condenses repeated observations and may be useful for describing worst observed severity, but it does not preserve the full sequence of symptoms. These are general statistical considerations, not a claim about the method used in this study.

How should counts and uncertainty be understood?

A count reports how many participants or events meet a definition, depending on the unit being counted. Counts alone do not express uncertainty or make an adjusted comparison. A confidence interval, when reported, communicates uncertainty around an estimate under a specified method. A p-value addresses compatibility with a statistical null model under its assumptions; it is not a measure of clinical importance or the probability that a hypothesis is true. No confidence interval or p-value for the primary endpoint or HIV acquisition is reported in the registry information.

For count outcomes, the appropriate analysis depends on what is counted, the observation period, the comparison being made, and features such as repeated events or differing follow-up. Over-dispersion is a general concern when count variability is greater than assumed by a simple model: if ignored, uncertainty can be understated. The record does not identify a count model or report whether over-dispersion was assessed. The primary endpoint is defined as participants reporting symptoms, so it should not automatically be treated as a count of every symptom episode.

What do the planning assumptions mean?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such sample-size calculations are planning illustrations: they describe the number of participants per arm under specified assumptions, not an observed trial result. They are not observed power and do not establish that a result is reliable or clinically important.

The registry’s general description distinguishes participant-per-arm planning figures from total-event planning figures for time-to-event outcomes. It does not report a trial-specific sample-size justification in the information, and the planning illustration should not be mistaken for evidence that the trial was designed around the primary endpoint. The record does not specify in this information whether an interim analysis was planned or conducted.

Which analysis details remain unknown?

The available record does not report the full statistical analysis plan, the model used for each outcome, the treatment of missing data, or the prespecified multiplicity procedure. It lists 15 outcome measures and 6 analyses, but those counts do not disclose which outcomes were tested together or how inference was controlled. The primary endpoint population is identified as the safety population; definitions of the analysis populations for the other outcomes are not reported in the registry record. Without these details and the relevant result estimates, the posted counts are best treated as descriptive entries rather than as a complete inferential analysis.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 15 outcome measures and 6 analyses, including secondary outcomes for serum VRC01 concentration and neutralization of founder viruses. Testing or summarizing several outcomes can raise multiplicity concerns: in general, as the number of statistical questions increases, the chance of at least one apparently unusual result can increase if no adjustment or interpretive strategy is used. The registry record does not report a multiplicity plan, hierarchy of outcomes, or adjustment method. It is therefore not possible to determine how the listed analyses were intended to support confirmatory conclusions.

The primary endpoint is described in several categories or time points and is not reduced to one comparison. That leaves the intended primary contrast and its inferential procedure unclear from the available record. The statistical analysis plan, interim-analysis procedures, and stopping rules are not reported in the registry record available for this analysis. No assumptions about these procedures should be inferred from the completed status.

The primary endpoint population is identified as the safety population. Other analysis populations and their definitions are not reported. The record also does not state how missing outcome observations, incomplete follow-up, or participants with changes in treatment exposure were handled. Missingness can matter when outcome availability differs between groups or is related to the outcome; in general, an analysis needs to state its assumptions and handling strategy. Without those details, the effect of missing information on the findings cannot be assessed.

These gaps do not establish that the study lacked such procedures; they mean the procedures are not reported in the registry record. The posted record does not provide the primary outcome or HIV-acquisition estimates needed to assess their precision or interpretation.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: any event in soc (1.2%), malaria (0.5%), ectopic pregnancy (0.3%), suicide attempt (0.3%), pelvic inflammatory disease (0.3%).

The registry reports serious-event entries separately for placebo, low-dose VRC01, high-dose VRC01, and pooled VRC01. The listed at-risk and affected counts are 637 and 26 for placebo, 642 and 10 for low-dose VRC01, 645 and 23 for high-dose VRC01, and 1287 and 33 for pooled VRC01. The listed death counts are 1, 2, 0, and 2, respectively. These are descriptive counts in the registry record; they do not, by themselves, show that treatment assignment caused or prevented an event.

The record also lists “Any Event in SOC” at 1.2%, malaria at 0.5%, and ectopic pregnancy, suicide attempt, pelvic inflammatory disease, and abortion incomplete at 0.3% each among the leading serious-event terms. The available information does not state the denominators or detailed event counts underlying these percentages. It also does not give uncertainty intervals or adjusted comparisons for these terms.

In general, serious adverse events are not interchangeable with all adverse events, and counts can be influenced by how events are defined, collected, and followed. The registry information does not provide the full definitions or adjudication procedures for these entries. The other-event figures are listed separately, but their precise category definition is not reported in the available record. These safety summaries should therefore be read as descriptive reporting, not as a complete comparative safety analysis.

12. What the Result Does, and Does Not, Mean

The record identifies a randomized study designed to evaluate safety and efficacy of VRC01 in reducing HIV-1 acquisition among high-risk, HIV-uninfected women. It specifies a local pain/tenderness primary endpoint, infusion schedules, and several posted safety counts. Those details describe the study and the outcomes that were tracked; they do not, on their own, answer whether VRC01 reduced HIV-1 acquisition.

The information available for this analysis does not report an HIV-acquisition result, effect estimate, confidence interval, or p-value. It also does not report the observed primary pain/tenderness results or a single primary-endpoint comparison. Consequently, the absence of an efficacy estimate should not be interpreted as evidence of benefit or lack of benefit. It means the registry record does not provide the result needed to assess that question.

The serious-event counts and listed percentages provide descriptive safety information. They do not establish causation, and without denominators for the displayed percentages, uncertainty intervals, event definitions, and comparative analyses, they cannot establish the magnitude or precision of differences between assigned groups. The death counts are also registry entries and should not be attributed to an intervention based on these counts alone.

In general, a randomized design can support a comparative interpretation when outcomes, analysis populations, methods, and uncertainty are reported. Randomization does not remove the need to examine missing data, adherence, follow-up, and prespecified analysis decisions. Those details are not reported in the registry record. The record’s completed status indicates that the study is marked completed; it does not itself communicate the direction, size, or certainty of any outcome.

The appropriate reading is therefore bounded: the study’s aim and design are described, and some safety summaries are posted, but the key efficacy result and primary endpoint comparison are not available in the information. Any broader conclusion about prevention or comparative safety would go beyond these reported data.

13. Why This Trial Matters Statistically

This trial is statistically notable for separating a broad prevention question from a local safety endpoint. The study’s stated aim concerns reducing HIV-1 acquisition, while its primary endpoint counts local pain and/or tenderness after infusion. These outcomes answer different questions. Keeping them distinct prevents a symptom endpoint from being mistaken for an infection-prevention result.

The design includes low-dose and high-dose VRC01 groups as well as placebo, and the posted safety record presents both separate dose categories and a pooled VRC01 category. Dose-specific reporting can preserve differences between regimens; pooling can summarize a broader intervention category, but it may conceal variation across doses. The record does not report the inferential comparisons needed to determine how these categories were analyzed or interpreted.

The primary endpoint involves repeated assessment after scheduled infusions and a maximum-grade summary. In general, repeated observations can require methods that account for within-participant dependence, while maximum summaries can simplify interpretation at the cost of detail about timing and recurrence. The registry record does not report the analysis method for these data. This makes the endpoint definition useful, but insufficient for judging the precision of a treatment comparison.

The trial also illustrates why transparent reporting of analysis populations, missing-data handling, multiplicity, and uncertainty matters. A completed randomized study can still be difficult to interpret when the relevant effect estimates and statistical procedures are not reported in the available registry information. The posted safety counts are informative as descriptive records, but they do not replace an outcome-specific comparative analysis.

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 principal limitation for interpreting this trial from the available registry record is that it does not include the observed result for the primary pain/tenderness endpoint or a single comparison across its categories or time points. It also does not include an HIV-acquisition effect estimate, confidence interval, or p-value, despite prevention being part of the study’s stated aim. The record’s completion status does not resolve these gaps.

The serious-event summary provides at-risk and affected counts by listed group, deaths, and selected event-term percentages. However, detailed event counts behind the percentages, their denominators, uncertainty intervals, and adjusted comparisons are not reported in the available information. The record also does not report enough detail to determine how the other-event category was defined or whether the event entries represent participants or event episodes in every case.

Further limitations include absent descriptions of the statistical analysis plan, missing-data handling, multiplicity strategy, and analysis populations beyond the safety population identified for the primary endpoint. The available record does not describe whether interim analyses were planned or conducted. These details are not reported in the registry record and should not be inferred.

The registry describes the treatment schedules and masking level, but does not specify who was masked or how masking was maintained. These limitations concern the completeness of the record available for interpretation; they do not establish that the study lacked additional methods or results outside the information.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluating the Safety and Efficacy of the VRC01 Antibody in Reducing Acquisition of HIV-1 Infection in Women — NCT02568215.
• Registry record last updated 2022-02-23; status last verified 2022-02.
• Results first posted 2022-02-08.
• 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.

18. Record Summary

NCT02568215 is a completed randomized, quadruple-masked, parallel phase 2b study of VRC01 and placebo in high-risk, HIV-uninfected women in sub-Saharan Africa. The registry lists enrollment of 1924, a start date of 2016-05, and primary completion on 2021-03-03. The interventions were low-dose VRC01, high-dose VRC01, and placebo, given by scheduled intravenous infusions.

The primary endpoint counts participants reporting local pain and/or tenderness, graded using the DAIDS table, with the maximum grade over the assessment period reported. The record also lists safety counts, deaths, and selected serious-event terms. It does not report the primary endpoint results or an HIV-acquisition effect estimate in the information available for this analysis. Details of the statistical plan, missing-data handling, and multiplicity procedures are not reported in the registry record.