Evaluating Safety and Immune Response to the HIV-1 CH505 Transmitted/Founder gp120 Adjuvanted With GLA-SE in Healthy, HIV-exposed Uninfected Infants: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluating Safety and Immune Response to the HIV-1 CH505 Transmitted/Founder gp120 Adjuvanted With GLA-SE in Healthy, HIV-exposed Uninfected Infants (NCT04607408), a randomized phase 1 study. The primary outcome is WHO Anthropometric Measure of Weight-for-Age Z-Score.

2. Clinical Question

The trial asked whether the study vaccine regimen could be evaluated for safety and immunogenicity in this infant population. Its registered primary endpoint is an anthropometric measure rather than a direct immune-response measure: infant weight is interpreted relative to age using a World Health Organization calculator. The registry record does not give a numerical primary-outcome estimate, a comparison between vaccine and placebo, or uncertainty intervals for that outcome.

The study had multiple parts and vaccine regimens. The vaccine groups received CH505TF gp120 with GLA-SE, while comparator groups received placebo. The registry describes randomized allocation and quadruple masking. It does not report the allocation method or explain how the sequence of parts affected enrollment or comparisons. The posted record therefore supports a description of the study question and design, but not a conclusion about differences in growth, safety, or immune response between groups.

3. Trial Design

The registry identifies this as a Phase 1, randomized, quadruple-masked, sequential study. It lists an enrollment of 38 and a completed status. The listed study start date is 2020-11-10, and the primary completion date is 2024-07-24. The sponsor is the HIV Vaccine Trials Network. The registry record does not explain the operational meaning of the sequential model or how it shaped decisions about moving between study parts.

The intervention was CH505TF gp120 with GLA-SE. In Part A, the vaccine group received 20 mcg of Stable CH505TF gp120 with 2.5 mcg of GLA-SE in a 0.25 mL intramuscular injection. In Part B, a vaccine group received 20 mcg of Stable CH505TF gp120 with 5 mcg of GLA-SE in a 0.5 mL injection. Part C included a group receiving the same vaccine and adjuvant amounts as Part B, and another group receiving 5 mcg of Stable CH505TF gp120 with 5 mcg of GLA-SE in a 0.5 mL injection. Placebo groups were also listed in each part. The registry describes these injections as being given at Weeks 0, 8, 16, 32, and 54.

These design features matter when interpreting any comparison. The vaccine regimens differed by part, and placebo groups were listed alongside them; the record does not provide a single pooled vaccine-versus-placebo estimate. Although randomization and quadruple masking are specified, the details of allocation, masking roles, and any planned comparisons are not reported in the registry record. Enrollment alone does not establish how many infants contributed to each outcome analysis, and the registry’s group-specific safety counts should not be treated as denominators for unreported immune or anthropometric outcomes.

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

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: Baseline characteristics are presented separately for mothers and infants. Mothers were enrolled to assess maternal HIV antibody response and did not receive study product.

6. Primary Endpoint

The registry lists the primary outcome as WHO Anthropometric Measure of Weight-for-Age Z-Score, measured over Measured at each study visit..

The primary endpoint is the World Health Organization anthropometric measure of weight-for-age Z-score. At each study visit, infant weight was measured and combined with age using the WHO anthropometric calculator. The measure expresses weight relative to the age-based reference population: a Z-score of 0 represents the population mean; a score less than -2 indicates an infant who is underweight; the range -2 to 2 indicates normal weight; and a score above 2 may indicate a growth problem, which is better assessed using weight-for-length. The registry notes that this outcome was not collected for mothers.

Weight-for-age is a standardized way to describe an infant’s size in relation to age, allowing measurements made at different ages to be interpreted on a common scale. In general, a Z-score helps distinguish a raw measurement from its position relative to a reference distribution. The outcome is relevant to a safety assessment because growth is an aspect of infant health that can be monitored during a study. However, the registry does not report the numerical Z-scores, their ranges, or changes over visits, nor does it provide a vaccine-versus-placebo estimate. The endpoint definition alone therefore does not show whether groups differed or how precisely any difference was estimated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Randomization is intended to make treatment assignment independent of participants’ measured and unmeasured characteristics, on average. It can support fair comparisons between assigned groups, but it does not guarantee that groups will be identical, especially when group sizes are limited. The registry identifies randomized allocation, but the allocation sequence, allocation ratio, and methods for concealing assignments are not reported in the registry record.

Masking means that specified people involved in a trial are kept unaware of treatment assignments. It can reduce the influence of expectations on care, reporting, or assessment. The record labels the study quadruple-masked, but does not identify which roles were masked or describe how masking was maintained. The label is therefore a design feature, not evidence by itself that masking was successful.

The study is also described as sequential, with Parts A, B, and C and different vaccine regimens across those parts. In general, a sequential design may use information from earlier stages when conducting later stages, but the registry does not explain whether that happened here, what decisions could be changed, or whether any prespecified progression rules were used. It would be inappropriate to infer a dose-escalation rule, interim analysis, or stopping boundary from the design label alone.

What does the primary summary measure?

The primary outcome specifies a median and a full range for weight-for-age Z-scores. The median is the middle value when observations are ordered; unlike a mean, it is less influenced by unusually high or low observations. The full range describes the lowest and highest observed values, so it communicates the spread at the extremes but does not show how observations are distributed between them. The registry does not post the median or range values. It also does not state whether the intended summaries are to be reported separately at every visit, despite defining measurement at each study visit.

How should uncertainty be understood?

In general, a confidence interval gives a range of values compatible with the data and the analysis assumptions at a stated confidence level. It communicates precision in a way that a point estimate alone cannot. The registry record does not report confidence intervals or other uncertainty measures for the primary endpoint, immune-response outcomes, or adverse-event counts. A p-value, if reported, would address compatibility with a specified null model; it would not measure clinical importance or replace an estimate and its uncertainty. No p-values for outcome comparisons are reported in the registry record.

Why can event counts be difficult to compare?

In general, event counts depend on how many participants were observed, how long they were followed, how events were defined, and whether participants could experience more than one event. A participant count with an event is not necessarily the same as a count of all event episodes. The registry supplies group-level counts at risk and affected for serious and other adverse events, but does not describe event-specific follow-up, recurrence handling, or the detailed event definitions. The counts should therefore be read as the record’s reported summaries, not converted into a rate or a treatment effect.

Over-dispersion is a general issue for count data: variability can exceed what a simple model assumes, for example when event counts vary more across participants than expected under that model. A model that ignores over-dispersion can produce uncertainty estimates that are too narrow. The registry record does not report a count model, a dispersion assessment, or a model-based adverse-event comparison, so no such method can be attributed to this trial.

The registry describes 25 outcome measures and 0 analyses. That information does not establish that no data were collected or that no analyses were conducted outside the registry; it means that analyses are not listed in this record. The statistical analysis plan, including the intended contrasts, covariate adjustments, handling of repeated measurements, and approach to uncertainty, is not reported in the registry record.

Any planning illustration based on a fraction of an observed effect should be understood as a hypothetical design calculation, not as an analysis of this trial’s power after completion. The stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is defined as a stated fraction of the observed effect. For time-to-event illustrations, the stated output is a total event count, while other illustrations are expressed as participants per arm. Such assumptions do not describe the actual design unless the record says they were used for it. The registry does not report the trial’s own sample-size justification, and an illustration is not observed power.

10. Multiplicity, Missing Data and Analysis Populations

The record lists 25 outcome measures, including the primary anthropometric measure and multiple secondary immune-response measures. These include antibody responses to pediatric vaccines, neutralization measures, binding-antibody responses, and antibody-dependent cellular cytotoxicity outcomes. When many outcomes or comparisons are considered, the chance of at least one apparently unusual result can increase. In general, a prespecified multiplicity strategy can control or contextualize that risk, for example by limiting confirmatory claims or adjusting inference across a defined family of tests. The registry record does not report such a strategy, identify a hierarchy among outcomes, or specify which comparisons were confirmatory.

The registry lists 0 analyses. It does not provide an analysis plan describing how missing measurements, incomplete follow-up, repeated visits, or protocol deviations were handled. It also does not report whether outcomes were analyzed according to assigned group, according to treatment received, or under another analysis population definition. The primary endpoint is associated with the safety population, but the record does not define that population in detail or identify analysis populations for the secondary outcomes.

In general, missing-data methods rely on assumptions about why measurements are unavailable. Complete-case analysis, imputation, and likelihood-based methods can answer different questions under different assumptions; the method should be stated rather than inferred. The registry does not report the amount or pattern of missing outcome data or any approach used to address it. These omissions limit the ability to assess whether posted estimates, if available elsewhere, would represent all randomized participants or a selected subset. The record’s lack of an analysis description is not evidence that missing data occurred, nor does it establish that they did not.

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: bronchiolitis (50.0%), lymphadenitis (10.0%), fungal skin infection (10.0%), pneumonia (10.0%), intestinal sepsis (6.2%).

The adverse-event record gives group-specific counts for participants at risk, participants affected by serious adverse events, participants affected by other adverse events, and deaths. The placebo groups are combined in the safety summary. The vaccine groups are listed separately for Part A, Part B, and two groups in Part C. These counts should be read as descriptive entries for the listed groups, not as adjusted comparisons. The registry does not report whether events were judged related to the intervention, the time at risk for each participant, or a statistical test comparing groups.

The record lists Bronchiolitis at 50.0% among the top serious-event terms. It also lists Lymphadenitis, Fungal skin infection, and Pneumonia at 10.0% each, and Intestinal sepsis and Ophthalmia neonatorum at 6.2% each. The denominator underlying these percentages and the precise basis for selecting the listed terms are not reported in the registry record. They should not be read as rates for a particular treatment group without that context.

No deaths are listed in any of the reported groups. The absence of listed deaths is a descriptive finding in this record; it does not establish that every possible safety outcome was measured or that a regimen is free of risk. Likewise, the fact that all participants at risk in some groups are listed as having other adverse events does not indicate severity, cause, or whether each participant had one event or multiple events. Those details are not reported.

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

The registry record establishes that this was a completed Phase 1 randomized, quadruple-masked trial of CH505TF gp120 with GLA-SE in healthy HIV-exposed uninfected infants, with placebo groups and several regimens across sequential parts. It specifies a primary weight-for-age Z-score outcome and a broad set of secondary immune-response outcomes. It also posts group-level adverse-event counts and a list of serious-event terms.

It does not report numerical primary-outcome results, immune-response estimates, group comparisons, confidence intervals, or p-values. Therefore, the record cannot establish whether weight-for-age Z-scores changed, whether immune responses differed by regimen, or how precisely any such difference was estimated. No conclusion about benefit or lack of benefit follows from the absence of posted outcome estimates.

The safety counts describe participants affected in the listed groups, but the record does not give adjusted analyses, exposure-adjusted rates, or attribution of events to vaccination. The groups vary by study part and vaccine regimen, so a simple comparison of their counts would not isolate an intervention effect. The reported absence of deaths is useful as a descriptive registry entry, but is not a comprehensive statement about all possible harms.

In general, a trial’s design can reduce some sources of bias, while reliable interpretation still depends on complete outcome reporting, prespecified analyses, and an account of uncertainty. Here, randomization and masking are recorded design features, but the statistical analysis plan and numerical outcome findings are not reported in the registry record. The appropriate interpretation is consequently limited: the registry describes what was planned and gives selected safety counts, but it does not provide the results needed to quantify comparative effects or their precision.

13. Why This Trial Matters Statistically

This trial is statistically notable because its question spans safety and several dimensions of immunogenicity, while its registered primary endpoint is an anthropometric measure. Those outcomes address different aspects of a Phase 1 study and require distinct interpretations. Weight-for-age Z-score describes growth relative to age; antibody and neutralization assays describe immune measurements. One type of outcome cannot stand in for another.

The sequential structure and the regimens across Parts A, B, and C also matter for interpretation. Vaccine amount, adjuvant amount, and injection volume vary across the listed groups. A comparison that pools groups or treats them as a single regimen could obscure those differences. The registry record does not report a prespecified pooling strategy, a dose-response analysis, or the statistical rationale for the sequence.

The study also illustrates why registry completion status and outcome reporting are separate issues. The record marks the study completed and lists an enrollment of 38, but does not post numerical results for the primary endpoint or the immune-response outcomes. Without estimates and uncertainty measures, readers cannot evaluate the magnitude or precision of those outcomes. The descriptive adverse-event counts offer some safety information but do not substitute for a comparative analysis.

More generally, interpretation of an early clinical trial depends not only on assignment and masking, but also on transparent definitions, complete reporting, and analysis methods matched to the design. The registry identifies several important design features, yet leaves the analysis plan and many result details unreported. That distinction is central to statistical reading: a clearly stated research question is not itself evidence for a particular answer.

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 trial-specific limitation in the registry record is that numerical results for the primary weight-for-age Z-score are not reported. Although the endpoint is defined as a median with a full range measured at each study visit, no values by visit or group are posted. The registry also does not provide numerical results for the listed immune-response outcomes. As a result, neither the direction nor the precision of those outcomes can be assessed from this record.

The design includes multiple parts, vaccine regimens, and placebo groups, but the record does not explain the planned comparisons or whether results were to be pooled across parts. The posted adverse-event summary combines the placebo groups and reports vaccine groups separately, while no comparative analysis is given. Differences in group counts alone cannot resolve whether observed event patterns reflect treatment, chance, follow-up, or other factors.

Details needed to assess the safety summaries are also absent, including the basis for the serious-event percentages, event attribution, follow-up duration by group, and handling of repeated events. The record lists the primary analysis population as the safety population but does not define it, and it does not describe analysis populations for secondary outcomes. It does not report missing-data methods, a statistical analysis plan, multiplicity handling, or uncertainty estimates.

These are limitations of what is reported in the registry record, not proof that the trial did not collect data or that analyses were not performed elsewhere. They mean that the posted information is insufficient for a full statistical assessment of comparative effects, precision, or robustness.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluating Safety and Immune Response to the HIV-1 CH505 Transmitted/Founder gp120 Adjuvanted With GLA-SE in Healthy, HIV-exposed Uninfected Infants — NCT04607408.
• Registry record last updated 2026-01-29; status last verified 2026-01.
• Results first posted 2025-08-06.
• 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

The registry describes NCT04607408 as a completed Phase 1 randomized, quadruple-masked, sequential trial sponsored by the HIV Vaccine Trials Network. It lists an enrollment of 38, a start date of 2020-11-10, and a primary completion date of 2024-07-24. The study evaluated CH505TF gp120 with GLA-SE in healthy HIV-exposed uninfected infants, with placebo groups and differing vaccine regimens across Parts A, B, and C.

The primary outcome was WHO weight-for-age Z-score, measured at each study visit and not collected for mothers. The record lists 25 outcome measures and 0 analyses. It provides group-level adverse-event counts, but numerical results for the primary anthropometric and immune-response outcomes, statistical comparisons, and uncertainty estimates are not reported in the registry record.