V710 First-In-Man (FIM) Study (V710-001): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for V710 First-In-Man (FIM) Study (V710-001) (NCT00303069), a randomized phase 1 study. The primary outcome is Number of Vaccine-related Serious Adverse Experiences Following Vaccination.

2. Clinical Question

The central question is about early safety and tolerability across increasing vaccine doses, rather than whether vaccination prevents infection. As a first-in-man study, it evaluated the vaccine in healthy adults and included a dose-escalation phase. The registry describes three vaccine dose groups and a placebo group, with the primary outcome focused on serious events considered related to vaccination.

The serious-event definition combines a relationship judgment with specified medical consequences. An investigator or qualified physician had to assess the adverse experience as related to study vaccine, and the experience had to meet at least one listed seriousness criterion. These criteria include death, persistent or significant disability or incapacity, prolongation of an existing inpatient hospitalization, a life-threatening event, a congenital anomaly or birth defect, cancer, or overdose.

The posted primary outcome counts participants with such an experience during follow-up through Day 84. The reported counts are zero for each of the four groups. This describes the observed serious vaccine-related events in the analyzed safety population; it does not, by itself, establish the probability of uncommon harms or address protection against Staphylococcus aureus infection.

3. Trial Design

This was a Phase I, randomized, double-blind, parallel-group, placebo-controlled dose-ranging study. Its official title describes a sequential-panel design evaluating the safety, tolerability, and immunogenicity of a single dose in healthy adults 18 to 55 years of age. The study is identified as a first-in-man evaluation of the 0657nI Staphylococcus aureus vaccine, also called V710 in the registry.

The registry reports enrollment of 124 participants and a completed study status. The brief summary describes an intended enrollment of approximately 120 participants. The study began in 2005-11, and primary completion is listed as 2006-07. These are registry dates and status details, not additional outcome follow-up dates beyond the stated endpoint timeframe.

Participants were assigned to V710 at 5 μg, 30 μg, or 90 μg, or to saline placebo. Each assignment involved a single 0.5 mL vaccination administered intramuscularly in the deltoid muscle. The brief summary describes dose escalation in Panel A before enrollment expanded to Panel B. Panel A is described as involving 36 subjects randomized in a 3:1 ratio, with 9 subjects at each of the three vaccine dose levels and 9 placebo subjects. The summary then describes expansion to the remaining 84 subjects in Panel B. Further details of Panel B’s allocation are not reported in the registry record.

Double-blinding is described for subjects, investigators, and Merck Research Laboratories personnel directly involved in the study. The registry classifies the overall model as parallel and the allocation as randomized. It does not report the randomization sequence method or the procedures used to maintain masking.

The primary outcome concerns vaccine-related serious adverse experiences through Day 84 postvaccination. The listed secondary outcome concerns participants with a ≥2-fold rise in antibody titer from baseline at Day 7 postvaccination. The registry also lists three outcome measures, but the further details and results of the other measures are not reported in the registry record. The focus of the posted primary result is safety, not a clinical infection outcome.

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: Subject was 18 to 55 years old; in good physical health based upon medical history, physical exam, and screening tests; able to understand study procedures and provided written consent; willing and able to complete entire study; and (if female) provided negative urine pregnancy test before vaccination and using an accepted method of birth control.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The population analyzed included all subjects who were randomized, vaccinated, and had safety follow-up.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Vaccine-related Serious Adverse Experiences Following Vaccination, measured over Through Day 84 postvaccination.

The primary endpoint is the number of participants with a serious adverse experience assessed as related to study vaccine through Day 84 postvaccination. The registry defines a serious experience using specified consequences: death; persistent or significant disability or incapacity; prolongation of an existing inpatient hospitalization; a life-threatening event; congenital anomaly or birth defect; cancer; or overdose. A participant’s experience also had to be assessed by an investigator or qualified physician as related to the study vaccine.

This endpoint is used to summarize serious safety events during the stated follow-up period. Its participant-count format is important: it reports how many participants met the outcome definition, rather than a total number of event episodes or a measure of symptom severity. A count of zero means no participant in the reported group was recorded as meeting this defined outcome in the analyzed population. It does not mean that no adverse experiences of any kind occurred.

The endpoint’s seriousness and relatedness requirements make it narrower than a count of all adverse experiences. The registry separately reports participants affected by other adverse experiences, and those counts are not interchangeable with the primary endpoint. The primary measure also does not assess vaccine efficacy, infection prevention, or longer-term safety beyond its stated timeframe. The registry record does not report additional endpoint adjudication procedures or a more detailed operational definition of vaccine relatedness.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary participant-level outcome: each participant either met the serious vaccine-related adverse-experience definition during the stated follow-up or did not. The registry reports the number meeting the definition in each group. A count is direct and easy to interpret, but it does not by itself quantify uncertainty or establish that risks are equal across groups.

What does a zero count convey?

General statistical explanation: a zero observed count means that the defined event was not recorded in the observed group during the specified follow-up. It does not prove that the event’s underlying probability is zero. When events are rare, a study can observe no cases even though the event remains possible in a broader population. Precision depends on the amount of relevant observation and the event frequency; a zero count alone does not provide a confidence interval or a bound on risk.

The reported outcome is participant-based, so it should not be read as an event-episode count. If a participant had more than one qualifying experience, the endpoint still concerns whether that participant was counted as having the outcome. The posted summary does not give event-level details or describe the handling of multiple qualifying experiences for an individual.

How should group counts be compared?

General statistical explanation: a comparison of binary outcomes can use group-specific proportions, differences, ratios, or statistical tests, depending on the analysis plan and data structure. These approaches address different questions and require explicit methods. The registry record does not report a statistical test, an effect estimate, a confidence interval, or a prespecified inferential comparison for the primary serious-event outcome. No such method or comparison should be inferred from the counts.

Zero counts in all groups also make some conventional comparative summaries difficult to interpret, because a ratio based on event risks may be undefined or uninformative when there are no observed events. Alternative methods can be considered in general, but the registry record does not state that any particular method was used. The appropriate description of the posted primary result is therefore the group-specific count and its defined timeframe.

What do the planning illustrations mean?

The registry record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The illustrations consider detecting a stated fraction of the observed effect. They are planning calculations, not evidence about the probability that this completed trial detected an effect. In particular, sample-size illustrations are not observed power. The record does not report that these assumptions were the study’s original design assumptions or sample-size justification.

General statistical explanation: a sample-size calculation asks how much information a future study might need under specified assumptions. Its result depends on the effect size chosen, the variability or event rate assumed, the allocation, the significance threshold, and the desired power. Changing those assumptions changes the planning result. Such calculations do not retrospectively establish that the current trial had adequate power, and they do not transform a descriptive zero count into evidence of equivalence or absence of risk.

Why are confidence intervals useful?

General statistical explanation: a confidence interval communicates the uncertainty around an estimate under a specified statistical method. It helps distinguish a precise estimate from one that is compatible with a wide range of values. For a rare binary outcome, an interval can remain informative when the observed count is zero, whereas the raw count alone cannot express the range of plausible underlying risks. The registry record does not report confidence intervals for the primary endpoint, so no interval-based claim can be made from the posted summary.

The registry reports an analysis population consisting of randomized participants who were vaccinated and had safety follow-up. This differs from simply describing everyone enrolled: participants who did not meet the stated analysis-population criteria are not included in the primary outcome population as defined. The record does not report how many participants were excluded from this population, whether any safety follow-up was incomplete, or how missing outcome information was handled.

In general, missing safety follow-up can affect interpretation if participants with incomplete observation differ from those with complete follow-up. The extent of that concern depends on the amount and pattern of missingness and the rules used to handle it. Since the record does not report those details, the posted counts should be understood within the stated analysis population, without assuming a particular missing-data procedure.

Finally, the serious-event outcome depends both on meeting one of the listed criteria and on an investigator or qualified physician judging the experience vaccine-related. The record does not report a separate adjudication process or a statistical analysis plan. These limitations do not change the reported counts, but they define what can be concluded from them: they are descriptive results for the recorded endpoint definition, analysis population, study groups, and follow-up period.

10. Multiplicity, Missing Data and Analysis Populations

The registry record does not report a multiplicity adjustment or a plan for controlling the chance of false-positive findings across multiple outcomes, dose groups, or analyses. It lists a primary safety outcome and a secondary antibody-titer outcome, and it reports three outcome measures and six analyses. Those listings alone do not establish which hypotheses were formally tested, whether testing was hierarchical, or whether any adjustment was applied. The record does not report a statistical analysis plan that resolves these questions.

The posted primary serious-event counts are descriptive, and the registry record does not report a formal inferential comparison across the three V710 doses and placebo. Without a reported test or interval, the counts should not be treated as statistically significant evidence for or against a group difference. The listed secondary outcome is the number of participants with a ≥2-fold rise in antibody titer from baseline at Day 7 postvaccination, but its results are not reported in the registry record.

The stated primary analysis population includes participants who were randomized, vaccinated, and had safety follow-up. The registry record does not report the numbers excluded from that population, the extent or pattern of missing follow-up, or how missing outcome information was handled. It also does not report whether any other analysis populations were used for outcomes beyond the primary safety measure.

These omissions limit assessment of how complete the safety observation was and how the analysis choices may affect inference. They do not alter the descriptive result as recorded: no participants in the reported groups were counted as having a vaccine-related serious adverse experience through Day 84 in the stated safety population.

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 non-serious adverse event terms

The primary safety outcome counts participants with serious adverse experiences judged related to study vaccine through Day 84 postvaccination. The posted count is 0 of 31 for V710 5 μg, 0 of 28 for V710 30 μg, 0 of 34 for V710 90 μg, and 0 of 31 for placebo. These are participant counts in the registry’s stated safety population, not counts of all adverse experiences.

The registry separately reports other adverse experiences affecting 18 of 31 participants in the V710 5 μg group, 19 of 28 in the V710 30 μg group, 28 of 34 in the V710 90 μg group, and 17 of 31 in the placebo group. These figures describe a broader category and should not be conflated with the narrower primary outcome. The record does not report the terms for these other experiences in this summary.

Zero qualifying serious events during this follow-up is a description of what was observed, not proof that serious events are impossible or that the groups have identical safety profiles. The registry record does not report confidence intervals or a formal statistical comparison for these counts. Interpretation is limited to the recorded definitions, analyzed population, and follow-up timeframe.

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

The result means that the registry’s posted primary safety summary recorded no participants with a serious adverse experience assessed as related to study vaccine in any of the four groups through Day 84 postvaccination. This applies to the analysis population defined as randomized, vaccinated participants with safety follow-up, and to the serious-event criteria specified in the registry.

It does not mean that no adverse experiences occurred. The separate counts for other adverse experiences show that participants were affected in each group, but those counts are not the primary serious-event outcome and the summary does not identify their terms. Nor does the zero count establish that the underlying risk of a serious event is zero. Events that are uncommon may not be observed in a study of limited size or follow-up, and no confidence interval is reported for this endpoint.

The result also does not establish that the vaccine prevents Staphylococcus aureus infection. The primary outcome is a safety measure, and the listed secondary outcome concerns antibody-titer rises rather than a clinical infection endpoint. The registry record does not report results for that secondary measure. The primary result cannot answer questions about vaccine efficacy, longer-term safety, or safety in populations other than the healthy adults 18 to 55 years of age studied.

Finally, the counts do not establish that the vaccine dose groups and placebo were statistically equivalent. The registry record does not report an inferential comparison, confidence intervals, or a prespecified equivalence or noninferiority framework for the serious-event outcome. The defensible reading is descriptive: no qualifying vaccine-related serious adverse experience was recorded in the posted primary safety results during the stated follow-up.

13. Why This Trial Matters Statistically

This study is statistically notable as a first-in-man, dose-ranging evaluation with an explicitly safety-focused primary outcome. The design included three vaccine dose levels and a placebo group, allowing safety observations to be organized across increasing doses. The sequential-panel structure described in the registry also reflects an initial dose-escalation phase followed by an expansion phase. These design features shape the kind of evidence the study can provide: early descriptive safety and immunogenicity information, rather than a definitive assessment of clinical benefit.

The primary outcome illustrates why the distinction between a participant count and a complete risk estimate matters. The posted results are straightforward to state: no participant met the primary serious-event definition in any group during the stated follow-up. But a zero count does not quantify uncertainty by itself. Statistical interpretation must account for the finite study population, observation period, event definition, and analysis population. The registry record does not report confidence intervals or a formal comparison, so the evidence remains descriptive for this endpoint.

The study also makes visible the difference between serious events and broader adverse-experience summaries. The serious-event outcome required both specified seriousness criteria and an assessment of vaccine relatedness, while the other adverse-experience counts capture a separate category. Keeping those measures distinct prevents a common interpretive error: treating a zero count for a narrowly defined serious endpoint as though it meant that no adverse experiences occurred.

More broadly, this record demonstrates how conclusions depend on reporting detail. Information about the analysis plan, missing follow-up, outcome adjudication, multiplicity, and uncertainty estimates would help readers assess robustness and precision. Where these details are not reported in the registry record, interpretation should remain bounded by the posted endpoint definition and counts rather than extending to unsupported comparative or causal claims.

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 outcome is restricted to serious adverse experiences assessed as related to study vaccine, using the seriousness criteria listed in the registry. It does not summarize all adverse experiences, and the posted summary does not provide the terms or clinical details for the other adverse experiences. The counts therefore provide limited information about the overall nature of tolerability findings.

Follow-up for the primary outcome is through Day 84 postvaccination. The result does not describe events beyond that period. The registry record does not report additional follow-up for this endpoint or provide a separate assessment of longer-term safety. A zero count within the specified timeframe cannot resolve whether events might occur later.

The study enrolled healthy adults 18 to 55 years of age. The posted result is therefore specific to the population studied and does not directly describe people outside that age range or people with other health characteristics. The registry identifies this as a Phase I first-in-man study, so its primary role was early evaluation rather than a clinical efficacy comparison.

The registry record does not report confidence intervals, a formal statistical comparison of the groups, or a detailed statistical analysis plan for the primary outcome. It also does not report the extent of missing safety follow-up, how missing outcomes were handled, or how relatedness judgments were standardized or adjudicated. These omissions limit evaluation of precision, between-group differences, and the potential effects of incomplete observation or outcome classification.

The registry reports enrollment of 124, while the brief summary describes an intended enrollment of approximately 120. These are different descriptions of planned and recorded enrollment, and the primary analysis population is separately defined as randomized, vaccinated participants with safety follow-up. The record does not provide a fuller reconciliation of enrollment and analysis-population counts. Interpretation should use the reported group counts and stated population definition rather than assuming all enrolled participants contributed to the primary result.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: V710 First-In-Man (FIM) Study (V710-001) — NCT00303069.
• Registry record last updated 2015-07-22; status last verified 2015-06.
• Results first posted 2010-10-20.
• 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

NCT00303069 is a completed, randomized, double-blind, parallel-group, placebo-controlled Phase I study of V710, a Staphylococcus aureus vaccine, in healthy adults 18 to 55 years of age. It evaluated single intramuscular doses of 5 μg, 30 μg, or 90 μg against saline placebo and used a sequential-panel, dose-ranging design.

The primary outcome was the number of participants with a serious adverse experience assessed as related to study vaccine through Day 84 postvaccination. The posted count was zero in each of the three V710 groups and in the placebo group. Other adverse experiences were separately reported, affecting 18 of 31, 19 of 28, 28 of 34, and 17 of 31 participants in the respective groups.

The primary safety population included randomized participants who were vaccinated and had safety follow-up. The registry record does not report confidence intervals, a formal comparison for the primary outcome, or details of missing-data handling. The result is a descriptive safety finding for the stated population, endpoint definition, and follow-up period.