A Study to Evaluate the Safety and Immunogenicity of V710 in Adults With Kidney Disease on Hemodialysis (V710-005)(COMPLETED): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Evaluate the Safety and Immunogenicity of V710 in Adults With Kidney Disease on Hemodialysis (V710-005)(COMPLETED) (NCT00572910), a randomized phase 2 study. The primary outcome is Geometric Mean Fold-rise (GMFR) in 0657n-specific Immunoglobulin G (IgG) Antibody Concentration From Baseline to 28 Days After the Administration of the Second V710 Vaccination.

2. Clinical Question

The trial examined whether V710 vaccination was associated with a measurable antibody response in adults with end-stage kidney disease receiving chronic hemodialysis, and assessed safety across vaccine regimens and placebo. The primary endpoint was the geometric mean fold-rise in 0657n-specific IgG antibody concentration from baseline to 28 days after the second V710 vaccination.

3. Trial Design

This was a randomized, double-blind, parallel-group Phase 2 study, with placebo control. Its title identifies the study population as adults with end-stage renal disease on chronic hemodialysis. The registry record reports an enrollment of 206 and a completed status. The recorded start was 2008-08 and primary completion was 2010-01.

The listed regimens varied by V710 dose, use of MAA, and whether a second V710 vaccination was given on Day 28. Group 1 received 60 mcg without MAA on Day 1 and Day 28; Group 3 received 60 mcg with MAA on those days; Group 5 received 90 mcg with MAA on those days. These are the three groups included in the primary endpoint results. Other listed regimens included a single V710 vaccination followed by placebo on Day 28, and a third dose of V710 or placebo on Day 180. The placebo group received placebo on Day 1, 28 and 180.

The primary endpoint was a laboratory antibody measure, rather than a clinical infection outcome. The record describes measurement of 0657n-specific IgG concentration by the LUMINEX™ assay. It reports results for the three groups receiving two V710 doses, with group sizes of 36, 37, and 36. These endpoint group sizes should not be treated as the total trial enrollment or as evidence of the number randomized to every regimen.

Randomization and double masking can help reduce allocation and assessment biases, but the registry record does not describe the randomization procedure, masking implementation, or allocation concealment. Further details of the design, including a statistical analysis plan and a sample-size justification, are not reported in the registry record.

4. Participant Flow and Accounting

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

Only the first 6 of 11 groups are shown.

Overall Study

Reasons for not completing this period:

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.

Only the first 6 of 7 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Geometric Mean Fold-rise (GMFR) in 0657n-specific Immunoglobulin G (IgG) Antibody Concentration From Baseline to 28 Days After the Administration of the Second V710 Vaccination, measured over Prevaccination to 56 days postvaccination.

The primary endpoint is the geometric mean fold-rise (GMFR) in 0657n-specific IgG antibody concentration. It compares the measured concentration at baseline with the concentration 28 days after administration of the second V710 vaccination. The registry describes the measurement as covering the prevaccination period to 56 days postvaccination and specifies use of the LUMINEX™ assay.

A fold-rise expresses a postvaccination antibody concentration relative to its baseline concentration. Taking a geometric mean is a way to summarize multiplicative changes across participants; it is often used for measurements that vary over a broad range or have a skewed distribution. This is a general statistical explanation, not a description of additional analyses in the registry record. The reported endpoint is therefore an antibody-response summary, not a count of infections or a direct measure of clinical protection.

The registry reports a GMFR and a 95% confidence interval for each of the three two-dose V710 groups: 18.9 (13.7 to 26.1) for 60 mcg without MAA, 15.1 (11.0 to 20.8) for 60 mcg with MAA, and 17.8 (13.0 to 24.3) for 90 mcg with MAA. A confidence interval describes uncertainty around a group estimate under the analysis used. It does not itself test whether groups differ, and the record does not report a formal comparison among the three estimates.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The reported endpoint is a geometric mean fold-rise in antibody concentration. A fold-rise compares a later measurement with a baseline measurement on a multiplicative scale. For example, a fold-rise is interpreted as a relative change, rather than as an absolute concentration difference. The geometric mean summarizes such relative changes across participants and is commonly used when the measurement scale is positive and values may vary multiplicatively. This is a general explanation of the statistic; the registry record does not describe all computational details used for this endpoint.

The primary endpoint description specifies 0657n-specific IgG antibody concentration measured with the LUMINEX™ assay. It states that the estimate covers baseline to 28 days after the second V710 vaccination. The outcome timeframe is described as prevaccination to 56 days postvaccination. The reported group values are geometric means, with 95% confidence intervals, and the group sizes are 36, 37, and 36. The record does not report the transformation, handling of values below assay limits, or other details needed to reproduce the calculations.

What does a 95% confidence interval convey?

In general, a confidence interval represents the uncertainty associated with an estimate under the statistical model and analysis procedure used. A narrower interval indicates greater precision in that estimate, while a wider interval indicates less precision. The intervals reported for the three group-specific GMFR estimates describe uncertainty around each group's value. They are not intervals for differences between groups, and they do not directly answer whether the regimens differ. The record does not give a method for constructing these intervals.

Why are group estimates different from treatment contrasts?

A group estimate describes a quantity within one group. A treatment contrast instead estimates the difference or ratio between groups and typically has its own uncertainty interval and statistical test. Here, the registry record reports group-level estimates for three V710 regimens, but no estimated contrast among those regimens or against placebo. Comparing the numerical values by eye would not provide the uncertainty for a between-group effect. In particular, the fact that the separate confidence intervals overlap does not establish that the groups are equivalent, nor does it quantify a difference.

Why does the geometric mean matter?

Antibody concentration responses are often summarized on a multiplicative scale because changes can be better described as relative rises than as fixed absolute increments. A geometric mean is constructed from the logarithmic scale and then expressed back on the original scale. This general property explains why geometric means are frequently used for antibody fold-rises. The registry record identifies the parameter as a geometric mean, but does not report whether logarithmic transformations were used in the analysis or the precise model used to derive the estimates.

What can be inferred from the reported participant counts?

The counts attached to the primary estimates identify the numbers included in those reported group summaries. They do not by themselves describe the number randomized to each group, the number who completed every vaccination, or the number with missing assay measurements. Overall enrollment was 206, but reasons for the smaller endpoint group counts and the analysis population definition are not reported in the registry record. Without those details, the reported estimates should be read as applying to the participants represented in each endpoint result, not automatically to all enrolled participants.

What role does over-dispersion play?

In general, over-dispersion occurs when data vary more than a model's assumptions expect. It can make uncertainty estimates too small if the analysis fails to account for the extra variability. This concept is relevant to count outcomes and some other model-based analyses, but the primary outcome is a geometric mean fold-rise, and the registry record does not report an over-dispersion model or a count-based analysis for it. It would therefore be inappropriate to infer that over-dispersion was assessed or that a particular adjustment was used.

The record lists four secondary outcome measures, all involving GMFR in 0657n-specific IgG concentration at additional timepoints. Their numerical results are not reported in the registry record. It also lists zero analyses. The registry does not state the test procedures, model covariates, analysis populations, missing-data handling, or multiplicity approach. No sample-size justification or interim-analysis plan is reported in the registry record. Any broader inference about the analysis strategy would go beyond the posted details.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint results consist of three group-specific estimates, one for each two-dose V710 regimen reported. The registry record does not describe a formal hypothesis-testing procedure or a planned family of comparisons among these groups. It also does not report p-values or confidence intervals for between-group contrasts. The record lists four secondary outcomes that assess GMFR at other timepoints, but their numerical results are not reported in the registry record. No adjustment for multiple comparisons is described; whether an adjustment was planned or used is not reported in the registry record.

The record lists zero analyses. That does not, by itself, establish that no analyses were conducted; it means the registry record does not provide analysis entries beyond the posted endpoint results. A statistical analysis plan, model specification, covariate strategy, interim-analysis details, and sample-size justification are not reported in the registry record.

The primary endpoint group sizes are 36, 37, and 36, compared with total enrollment of 206. The registry record does not define the analysis population, explain the difference between enrollment and endpoint group counts, or state how missing assay values were handled. It does not report how many participants had missing measurements or whether any imputation or other missing-data method was used. The implications of missingness therefore cannot be assessed from this record.

These gaps matter because the interpretation of confidence intervals and comparisons depends on the analysis population, model, and prespecified testing strategy. Without those details, the strongest supported reading is descriptive: the posted results give group-level antibody fold-rise estimates and their confidence intervals, without a documented inferential comparison across regimens.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: cardiac arrest (10.5%), coagulopathy (5.9%), atrial fibrillation (5.9%), cardiac failure congestive (5.9%), cardiopulmonary failure (5.9%).

The registry record lists serious adverse events and other adverse events by regimen group. For serious adverse events, the entries give the number at risk and the number affected. For example, in the listed V710 (60 mcg / 60 mcg / 60 mcg) group, 18 were at risk and 2 were affected; in the corresponding group with MAA, 19 were at risk and 0 were affected. The placebo group lists 18 at risk and 3 affected. These are counts in the registry record, not estimates adjusted for differences in exposure or follow-up.

The record also lists counts for other adverse events. In the placebo group, 18 were at risk and 7 were affected. The denominators and affected counts vary across the listed regimens, so the entries should be read group by group rather than as a single pooled summary. The record does not provide deaths for these groups.

Serious-event terms listed include Cardiac arrest at 10.5%, Coagulopathy at 5.9%, Atrial fibrillation at 5.9%, Cardiac failure congestive at 5.9%, Cardiopulmonary failure at 5.9%, and Myocardial infarction at 5.9%. The registry record does not clarify in this listing the denominator or analysis method underlying each percentage. These listed terms and percentages should not be treated as comparative risk estimates between regimens.

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

The posted primary results show that each of the three reported two-dose V710 groups had a geometric mean fold-rise in 0657n-specific IgG concentration above baseline at the specified measurement time. The estimates were 18.9 for 60 mcg without MAA, 15.1 for 60 mcg with MAA, and 17.8 for 90 mcg with MAA. Their 95% confidence intervals provide a measure of uncertainty around each group estimate.

These are descriptive immunogenicity results. The record does not report a statistical comparison among the three estimates, and it does not report a primary endpoint estimate for the placebo group. Consequently, the results do not establish that one regimen produced a greater response than another, or quantify the difference between a V710 regimen and placebo. Separate group confidence intervals should not be interpreted as if they were a confidence interval for a treatment contrast.

The measured outcome is an antibody concentration response, not a clinical outcome. The posted primary endpoint does not show how many participants developed Staphylococcus aureus infection, and the registry record does not report a primary infection-prevention result. It therefore cannot, on its own, establish whether the measured antibody response corresponds to a difference in clinical outcomes.

Safety results are also listed, including counts of participants affected by serious and other adverse events. These counts describe the registry's reported groups, but the record does not supply enough information to interpret them as adjusted comparisons or to establish how event risk differed between regimens. The results should be understood within the scope of the recorded outcomes and the analyses actually posted, rather than as a complete account of efficacy or safety.

Overall, the registry results characterize group-level antibody responses and report adverse-event counts for several regimens. They do not include the inferential comparisons, secondary endpoint values, analysis-population details, or missing-data methods needed for broader conclusions.

13. Why This Trial Matters Statistically

This trial is statistically informative because it illustrates the distinction between an outcome estimate within a group and a comparison between randomized groups. Randomization is part of the study design, but the posted primary results are separate geometric mean fold-rises for three V710 regimens. They are not reported as contrasts. The distinction matters: a set of group summaries cannot provide the estimated difference, uncertainty, or test for a treatment comparison unless those quantities are also calculated and reported.

The endpoint is an immunogenicity measure summarized on a multiplicative scale. Reporting geometric mean fold-rise with confidence intervals gives readers both a central estimate and an indication of its precision. At the same time, the outcome is a laboratory antibody measure, not a clinical infection outcome. Statistical interpretation must follow the endpoint that was actually measured.

The registry record also makes visible several reporting limits that affect interpretation: the endpoint group sizes are smaller than overall enrollment, but the analysis population and missing-data handling are not described; four secondary outcomes are named without posted results; and no analysis entries are listed. These details are important when assessing the completeness of the statistical record and the scope of conclusions supported by the posted results.

For clinical researchers, the key statistical lesson is to distinguish observed group summaries from tested treatment effects, and to distinguish a biomarker response from a clinical outcome. The record supports a descriptive account of the antibody estimates and the listed safety counts. It does not provide the additional comparisons and methods needed to assess differences between regimens or connect antibody response to clinical benefit.

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 primary results cover only the three groups receiving two V710 vaccinations. Although the study included additional V710 schedules and a placebo group, the registry record does not report primary endpoint estimates for those other groups. There is no posted treatment contrast or formal comparison among the three reported regimens. This limits interpretation to the group-specific antibody summaries.

Endpoint group sizes are 36, 37, and 36, while total enrollment is 206. The registry record does not explain the difference, define the primary endpoint analysis population, or describe withdrawals, missing measurements, or exclusions. It is therefore not possible from the record to assess whether the reported groups represent all randomized participants or to evaluate potential bias from missing endpoint data.

The endpoint is a laboratory measure of 0657n-specific IgG concentration. The primary outcome does not report infection occurrence or another clinical endpoint. Although adverse events are listed, the registry record does not report deaths for the displayed groups or provide enough detail to evaluate differences in event risk by regimen. The serious-event percentages are listed without a denominator or method in the record excerpt.

Additional methodological details are also absent. The statistical model, confidence-interval method, assay-limit handling, multiplicity plan, interim analyses, and sample-size justification are not reported in the registry record. The four named secondary outcomes have no numerical results reported. These omissions limit reproducibility and the extent to which the posted results can support comparative inference.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study to Evaluate the Safety and Immunogenicity of V710 in Adults With Kidney Disease on Hemodialysis (V710-005)(COMPLETED) — NCT00572910.
• Registry record last updated 2015-04-03; status last verified 2015-03.
• Results first posted 2011-08-15.
• 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

NCT00572910 is a completed randomized, double-blind, placebo-controlled, parallel-group Phase 2 study of V710 in adults with end-stage kidney disease receiving chronic hemodialysis. The registry record reports enrollment of 206, a start in 2008-08, and primary completion in 2010-01.

The primary endpoint was geometric mean fold-rise in 0657n-specific IgG concentration after the second V710 vaccination. Results are reported for three two-dose regimens: 60 mcg without MAA, 60 mcg with MAA, and 90 mcg with MAA. The group estimates were 18.9, 15.1, and 17.8, with 95% confidence intervals of 13.7 to 26.1, 11.0 to 20.8, and 13.0 to 24.3, respectively.

The record lists four secondary antibody outcomes and adverse-event counts, but does not report numerical secondary endpoint results or formal comparisons among primary endpoint groups. Analysis populations and missing-data methods are not reported in the registry record.