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 Multivalent HPV (Human Papillomavirus) Vaccine Study in 16- to 26-Year Old Men and Women (V503-003) (NCT01651949), a non-randomized phase 3 study. The primary outcome is Geometric Mean Titers (GMTs) to the HPV Types Contained in the 9vHPV Vaccine.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01651949 |
| Phase | Phase 3 |
| Condition | Genital Warts, Anal Cancer, Anal Intraepithelial Neoplasia |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 2520 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Merck Sharp & Dohme LLC |
| Results posted | Yes |
2. Clinical Question
Population
The study enrolled healthy males and females aged 16 to 26 years. The listed groups were females, heterosexual males, and men who have sex with men (MSM). The primary analysis population was narrower: heterosexual male and female participants who received all 3 vaccinations, were seronegative to the relevant HPV type at baseline, and had Month 7 immunogenicity results for that type.
Intervention
Participants received 9vHPV, a vaccine targeting HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. The described schedule was an intramuscular injection on Day 1, Month 2, and Month 6.
Comparator
The primary comparison was between heterosexual males and females receiving the vaccine. It was not a comparison with an untreated or placebo group. MSM were included as a study group, but the primary hypothesis described in the registry record concerns heterosexual males compared with young women.
Primary question
At four weeks after the third vaccination, were antibody responses in heterosexual males non-inferior to those in young women? Responses were assessed using geometric mean titers for the HPV types included in the vaccine. The registry record does not report the numerical titers, confidence intervals, or a conclusion about whether the non-inferiority criterion was met.
The study was designed to bridge efficacy findings in young women to young men by examining whether the groups had similar immunogenicity and safety profiles. That is a question about the immune response and tolerability observed in the studied groups, not a direct comparison of clinical disease outcomes. The listed conditions include genital warts, anal cancer, and anal intraepithelial neoplasia, but the primary endpoint described is antibody titer rather than occurrence of those conditions. The registry record does not report results showing whether the antibody-response objective was achieved.
3. Trial Design
This was a phase III, parallel-group study with nonrandomized allocation and no masking. The registry record reports enrollment of 2520 and a completed study. The listed start date is 2012-10-29, and the primary completion date is 2014-08-04. Merck Sharp & Dohme LLC is listed as the sponsor.
The intervention was 9vHPV vaccine. Females, heterosexual males, and MSM aged 16 to 26 years were described as receiving an intramuscular 0.5 mL injection on Day 1, Month 2, and Month 6. The descriptions specify healthy participants. The registry record does not describe a placebo or an untreated control group.
Because allocation was nonrandomized, the groups were not formed through random assignment. Differences between male and female participants could therefore reflect group characteristics as well as any differences in measured responses. The registry record itself cautions that the arms are not a like-for-like control comparison. The primary question was instead a non-inferiority immunogenicity comparison between heterosexual males and females who received the vaccine.
The primary endpoint was geometric mean titer to the HPV types included in the vaccine, assessed four weeks after vaccination 3, at Month 7. Antibodies were measured with a Competitive Luminex Immunoassay, and titers were reported in milli Merck Units/mL. A per-protocol non-inferiority analysis is described for heterosexual males and females. Details of the analysis beyond that description, including the non-inferiority margin, are not reported in the registry record.
The registry record lists 6 outcome measures and 22 analyses. It also lists seroconversion to vaccine HPV types as a secondary outcome. The number of outcomes and analyses does not by itself indicate how results were prioritized or how statistical error across analyses was handled; those details 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.
Overall Study
| Stage | Heterosexual Males | Females | Men Who Have Sex With Men (MSM) |
|---|---|---|---|
| STARTED | 1106 | 1101 | 313 |
| Vaccination 1 | 1103 | 1099 | 313 |
| Vaccination 2 | 1089 | 1069 | 298 |
| Vaccination 3 | 1067 | 1037 | 291 |
| COMPLETED | 1053 | 1015 | 282 |
| NOT COMPLETED | 53 | 86 | 31 |
Reasons for not completing this period:
| Reason | Heterosexual Males | Females | Men Who Have Sex With Men (MSM) |
|---|---|---|---|
| Unknown status | 4 | 4 | 0 |
| Lost to Follow-up | 30 | 56 | 20 |
| Protocol Violation | 0 | 2 | 1 |
| Physician Decision | 0 | 2 | 0 |
| Adverse Event | 0 | 2 | 1 |
| Screen failure | 2 | 2 | 0 |
| Withdrawal by Subject | 17 | 18 | 9 |
Analysis population for the primary outcome, as defined in the registry: The analysis set includes heterosexual male and female participants who received the 3 vaccinations, were seronegative to the appropriate HPV type at baseline, and had Month 7 immunogenicity results for the appropriate HPV type. Per-protocol non-inferiority analysis compared heterosexual males and females only.
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 | Heterosexual Males | Females | Men Who Have Sex With Men (MSM) | Total |
|---|---|---|---|---|---|
| Participants analysed | 1106 | 1101 | 313 | 2520 | |
| Age, Continuous | Years | 20.8 (SD 3.0) | 21.3 (SD 2.9) | 22.2 (SD 2.4) | 21.2 (SD 2.9) |
| Sex: Female, Male: Female | Participants | 0 | 1101 | 0 | 1101 |
| Sex: Female, Male: Male | Participants | 1106 | 0 | 313 | 1419 |
6. Primary Endpoint
The registry lists the primary outcome as Geometric Mean Titers (GMTs) to the HPV Types Contained in the 9vHPV Vaccine, measured over Four weeks post vaccination 3 (Month 7).
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | milli Merck Units/mL |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was geometric mean titers (GMTs) of serum antibodies to HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. Titers were measured with a Competitive Luminex Immunoassay and expressed in milli Merck Units/mL. The measurement time was four weeks after the third vaccination, identified as Month 7.
A GMT summarizes antibody measurements using a geometric rather than an arithmetic average. As a general statistical explanation, geometric summaries are commonly used for measurements that are positive and vary multiplicatively: analysis on a logarithmic scale makes proportional differences more suitable to summarize than absolute differences. The registry record does not report the individual titers or the calculation details used for the GMTs.
The endpoint was chosen to address an immunogenicity question: whether the antibody response in heterosexual males was non-inferior to that in young women. The registry record describes the analysis set as participants who received all 3 vaccinations, were seronegative to the relevant HPV type at baseline, and had a Month 7 result for that type. The primary outcome is therefore specific to the measured antibody response, the stated analysis population, and the post-vaccination time point.
The registry record reports a 95% confidence interval as the measure of dispersion but does not provide numerical GMT estimates or intervals. A confidence interval generally expresses the uncertainty around an estimated quantity under the analysis assumptions. Without the estimates, interval limits, and non-inferiority margin, the primary result cannot be interpreted as meeting or failing the stated criterion from the registry record alone.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The study’s stated primary question was whether antibody responses at Month 7 in heterosexual males were non-inferior to responses in young women. The endpoint was GMT for each HPV type included in the vaccine, with a 95% confidence interval identified as the dispersion measure. However, numerical primary results are not reported in the registry record. There are no posted GMT estimates, confidence interval limits, or stated conclusion about the non-inferiority hypothesis in the record.
That absence matters for interpretation. A non-inferiority conclusion depends on the estimated comparison, its uncertainty, and a prespecified margin defining how much lower a response could be while still meeting the criterion. The margin is not reported in the registry record. Without it and the numerical results, readers cannot determine whether the comparison met the criterion, how close it was to any threshold, or how precisely the responses were estimated.
The design also places limits on causal interpretation. This was a nonrandomized study with no masking, and the registry record notes that the arms are not a like-for-like control comparison. The primary comparison is between male and female participants who received the vaccine, not between vaccine and placebo. Differences between groups should therefore be read as a comparison of measured immune responses in the described populations, rather than as an isolated treatment effect.
The registry record describes a per-protocol analysis set requiring receipt of all 3 vaccinations, baseline seronegativity to the relevant type, and an available Month 7 result for that type. This defines the participants contributing to the stated primary analysis; the record does not provide the number contributing to each HPV-type analysis or explain how participants without the required measurements were handled. The effect of missing measurements on the result cannot be assessed from the reported information.
The secondary outcome listed is the percentage of participants with seroconversion to the vaccine HPV types. The record reports 6 outcome measures and 22 analyses, but does not describe whether or how multiplicity was addressed. Numerical results for seroconversion are not reported in the registry record either.
Safety information is summarized separately for heterosexual and MSM males together and for females. The record reports participants affected by serious adverse events and by other adverse events, as well as selected serious-event terms and their percentages. Those figures describe events recorded in the study; in a nonrandomized comparison without an untreated group, they do not by themselves establish that the vaccine caused an event or provide a comparative estimate of risk.
Overall, the registry record describes the study question, design, endpoint, analysis population, and selected safety counts, but does not report the numerical primary efficacy-related immunogenicity results. Interpretation of the central non-inferiority question is therefore limited to the planned comparison and cannot extend to a conclusion about its outcome.
9. Statistical Methods Explained
The registry record describes a non-inferiority comparison of antibody responses in heterosexual males and young women. In general, a non-inferiority study asks whether an outcome in one group is not unacceptably worse than an outcome in a comparison group, according to a prespecified margin. The margin is essential: it defines the largest difference considered compatible with non-inferiority. The margin for this study is not reported in the registry record, and numerical estimates and confidence intervals for the primary comparison are not reported either. Consequently, the non-inferiority decision cannot be reconstructed from the information available.
What does a geometric mean titer summarize?
A geometric mean is a way to summarize positive measurements whose variation is more naturally considered in multiplicative terms. In general, the calculation uses logarithms, averages on that scale, and transforms the result back to the original measurement scale. This makes it a common summary for antibody titers, which can span a wide range. The endpoint description identifies GMTs and their unit, milli Merck Units/mL, but does not report the numerical titers or detailed calculation procedures.
The primary outcome was measured separately for the vaccine’s listed HPV types. The record describes a 95% confidence interval for dispersion. As a general explanation, a confidence interval conveys uncertainty around an estimated quantity under the statistical model and analysis assumptions. Its width is relevant to precision, while its position relative to a non-inferiority margin would be relevant to the non-inferiority decision. The interval limits and margin are not reported in the registry record, so neither precision nor the decision can be evaluated numerically.
Why define an analysis population?
The primary analysis set is described as heterosexual male and female participants who received the 3 vaccinations, were seronegative to the relevant HPV type at baseline, and had an immunogenicity result for that type at Month 7. This is a type-specific, per-protocol description. In general, restricting an analysis to participants who followed the vaccination schedule and met measurement criteria can focus the comparison on responses among participants with the specified exposure and observations. It can also mean that the analysis does not represent every enrolled participant. The record does not report the number included in each type-specific analysis, the exclusions, or how outcomes for participants without a Month 7 measurement were treated.
The record says that a per-protocol non-inferiority analysis compared heterosexual males and females. It does not report whether additional analysis populations were used, how results from different populations were compared, or what sensitivity analyses were conducted. Those details should not be inferred from the label “per-protocol.”
What does nonrandomized allocation imply?
With nonrandomized allocation, participants are not assigned to groups at random. As a general statistical consideration, groups may differ in characteristics that are related to the outcome, even when both receive the same intervention. The registry record explicitly notes that the arms are not a like-for-like control comparison. The primary comparison is useful as a description of antibody responses in the specified male and female analysis groups, but the design does not support treating those groups as if they were randomized treatment and control arms.
The study was also unmasked. In general, masking can reduce the possibility that awareness of group or treatment status influences certain measurements, reporting, or study processes. The registry record does not specify what procedures, if any, were used to limit such influences. The primary endpoint is a laboratory antibody measurement, but the absence of masking remains part of the study design and should be considered when reading the full set of outcomes.
How should multiple outcomes and analyses be considered?
The registry record lists 6 outcome measures and 22 analyses. When a study evaluates multiple endpoints, types, groups, or analyses, the chance of at least one apparently notable result can increase if each is assessed independently without an appropriate strategy. This is a general statistical concern, not a conclusion that the reported analyses are invalid. The registry record does not report a multiplicity adjustment, hierarchy among outcomes, or other method for managing multiple comparisons. The primary endpoint is identified, but that alone does not establish how the remaining analyses were handled.
Seroconversion is listed as a secondary outcome. It concerns the percentage of participants meeting a seroconversion definition for the vaccine HPV types. The record does not provide the definition used, numerical results, or details about uncertainty for those results. No interpretation of whether seroconversion criteria were met can be made from the listed outcome name alone.
What do the planning illustrations represent?
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. It states that the effect to detect is a specified fraction of the observed effect. In general, such calculations illustrate how a sample size might relate to a chosen effect and assumptions. They are not observed power, do not establish the study’s original design rationale, and do not replace the trial’s actual analysis. The record does not report the trial’s own sample-size justification or statistical plan.
For time-to-event planning calculations, the record says that the stated total is the number of events; other planning calculations are expressed as participants per arm. Those conventions describe the planning illustrations, not outcomes observed in the trial. The underlying planning results and the assumptions used for the trial’s original design are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 6 outcome measures and 22 analyses, including a primary GMT outcome and a secondary seroconversion outcome. It does not report a statistical hierarchy for the outcomes, a multiplicity adjustment, or another method for accounting for the number of comparisons. As a general statistical matter, evaluating multiple outcomes or subgroups can increase the chance of finding an apparently notable result by chance if comparisons are treated independently. The count of analyses alone does not establish whether that concern affected the study’s conclusions.
Numerical primary and secondary outcome results are not reported in the registry record. Thus, readers cannot inspect how estimates and uncertainty varied across HPV types or analyses, or determine how any multiplicity strategy might have changed interpretation. The non-inferiority margin and complete statistical decision procedure are also not reported, so the central hypothesis cannot be assessed from the record.
The stated primary analysis set required participants to have received all 3 vaccinations, to be seronegative at baseline for the relevant type, and to have a Month 7 result for that type. This makes the population contributing to analysis depend on adherence, baseline status, and measurement availability. The record does not report missing-data methods, reasons for missing measurements, numbers excluded from each analysis, or sensitivity analyses. It is therefore not possible to evaluate whether missing data could have influenced the results.
The registry record also does not report the full statistical analysis plan, whether interim analyses were conducted, or the sample-size justification used to design the trial. The planning illustrations described in the record are not a substitute for those details or for the numerical trial results.
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 |
|---|---|---|---|
| Heterosexual and MSM Males | 23 | 1394 | 1.6% |
| Females | 26 | 1075 | 2.4% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Heterosexual and MSM Males | 976 of 1394 |
| Females | 924 of 1075 |
Most frequent serious adverse event terms
| Event term | Organ system | Heterosexual and MSM Males | Females |
|---|---|---|---|
| Abortion spontaneous | Pregnancy, puerperium and perinatal conditions | 0 of 1394 | 4 of 1075 |
| Abortion induced | Surgical and medical procedures | 0 of 1394 | 4 of 1075 |
| Appendicitis | Infections and infestations | 2 of 1394 | 1 of 1075 |
| Constipation | Gastrointestinal disorders | 0 of 1394 | 2 of 1075 |
| Concussion | Injury, poisoning and procedural complications | 2 of 1394 | 0 of 1075 |
| Migraine | Nervous system disorders | 1 of 1394 | 1 of 1075 |
| Ectopic pregnancy | Pregnancy, puerperium and perinatal conditions | 0 of 1394 | 2 of 1075 |
| Atrioventricular block second degree | Cardiac disorders | 1 of 1394 | 0 of 1075 |
| Familial periodic paralysis | Congenital, familial and genetic disorders | 1 of 1394 | 0 of 1075 |
| Vomiting | Gastrointestinal disorders | 0 of 1394 | 1 of 1075 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Heterosexual and MSM Males | Females |
|---|---|---|---|
| Injection site pain | General disorders | 886 of 1394 | 893 of 1075 |
| Injection site swelling | General disorders | 285 of 1394 | 408 of 1075 |
| Injection site erythema | General disorders | 291 of 1394 | 348 of 1075 |
| Headache | Nervous system disorders | 200 of 1394 | 246 of 1075 |
Serious events with the highest arm-level rate: abortion spontaneous (0.4%), abortion induced (0.4%), constipation (0.2%), ectopic pregnancy (0.2%), appendicitis (0.1%).
The registry record reports safety counts for two categories: “Heterosexual and MSM Males” and “Females.” For serious adverse events, it lists 23 affected participants among 1394 at risk in the male category and 26 among 1075 at risk in the female category. For other adverse events, it lists 976 affected participants among 1394 at risk in the male category and 924 among 1075 at risk in the female category. These are counts reported in the registry record; no additional rates or comparisons are calculated.
The male safety category combines heterosexual males and MSM, so its figures should not be read as a separate estimate for either male subgroup. The primary immunogenicity comparison, by contrast, is described for heterosexual males and females. The groups were not randomized, and the record cautions that the arms are not a like-for-like control comparison. The safety counts therefore do not isolate a causal effect of vaccination or establish a comparative risk.
The registry record lists selected serious-event terms with percentages: spontaneous abortion, 0.4%; induced abortion, 0.4%; constipation, 0.2%; ectopic pregnancy, 0.2%; appendicitis, 0.1%; and concussion, 0.1%. These are listed as top serious terms, but the record does not provide further detail about their group attribution or the event-specific denominators in this summary. The deaths field is not reported in the registry record. A safety follow-up timeframe and additional event-context details are also not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The study addresses an immunogenicity question: whether antibody responses in heterosexual males receiving 9vHPV were non-inferior to those in young women. It evaluates geometric mean titers for the vaccine HPV types at Month 7, four weeks after vaccination 3. The endpoint is a measure of antibody response at a specified time, not a direct measure of the occurrence of genital warts, anal cancer, or anal intraepithelial neoplasia.
The record describes the study’s intervention, population, timing, endpoint, and per-protocol analysis population. It also describes a secondary seroconversion outcome and reports selected safety counts. However, the numerical primary GMT results, confidence interval limits, and conclusion about non-inferiority are not reported in the registry record. Numerical seroconversion results are not reported either. The central comparison therefore cannot be characterized as meeting or not meeting its objective on the basis of the record’s reported results.
The design was nonrandomized and unmasked, and there was no placebo or untreated comparator described. The registry record notes that the arms are not a like-for-like control comparison. Accordingly, the male-female immunogenicity comparison should be understood as a comparison of responses in the specified participant groups, not as a randomized contrast that isolates treatment effects. The safety counts likewise describe recorded events in the listed categories and do not establish that vaccination caused them.
The analysis population was restricted to participants who received the full vaccination schedule, were seronegative at baseline for the relevant HPV type, and had a Month 7 measurement for that type. The record does not report how missing measurements were handled or how many participants contributed to each type-specific analysis. These omissions prevent a full assessment of how broadly the analysis represents enrolled participants.
In short, the registry record establishes what the trial set out to compare and how the primary antibody outcome was defined, but it does not report the numerical findings needed to judge the comparison’s magnitude, precision, or non-inferiority conclusion. No conclusion about clinical disease outcomes follows from the endpoint description alone.
13. Why This Trial Matters Statistically
This trial illustrates how an immunogenicity endpoint can be used to address a comparison between population groups when the primary question is about antibody response rather than a clinical disease event. The registry record describes a strategy of comparing heterosexual males with young women on GMTs after a shared vaccination schedule. That objective differs from estimating a vaccine-versus-placebo effect, because no untreated or placebo group is described.
It also highlights why a non-inferiority question requires more than a statement that two groups have similar responses. The margin, estimate, and uncertainty are needed to judge whether the difference is compatible with the prespecified criterion. The registry record does not report the margin or numerical GMT results, so the statistical decision cannot be evaluated from the information available.
The study’s nonrandomized allocation is important to the interpretation of group comparisons. In general, randomization helps balance measured and unmeasured participant characteristics across comparison groups. Without it, observed group differences may reflect differences in the groups as well as differences in the measured outcome. The registry record explicitly warns that the arms are not a like-for-like control comparison.
The per-protocol population description also makes analysis-population choices visible: participants needed to complete the stated vaccination schedule and have baseline and Month 7 information relevant to each HPV type. Such requirements can be meaningful for immunogenicity analyses, but readers also need information about exclusions and missing measurements to assess the reach and robustness of the results. Those details are not reported in the registry record.
Finally, the record lists multiple outcomes and analyses, while not reporting a multiplicity strategy or numerical results. This underscores the value of clear reporting of outcome priority, analysis methods, uncertainty, and missing-data handling. Without those elements, a stated statistical objective can be understood, but its evidential result cannot be independently interpreted in full.
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.
A central limitation of the available registry information is that it does not report numerical primary endpoint results. Although GMTs and 95% confidence intervals are specified, the estimates and interval limits are absent, as is the non-inferiority margin. The primary statistical conclusion therefore cannot be assessed.
The allocation was nonrandomized and masking was absent. The registry record cautions that the arms are not a like-for-like control comparison. The primary comparison is between heterosexual males and females who received the vaccine, so it does not provide a randomized vaccine-versus-control contrast. The safety category for males combines heterosexual males and MSM, which also prevents reading those safety counts as subgroup-specific figures.
The stated primary analysis population is restricted to participants who received all 3 vaccinations, were seronegative for the relevant HPV type at baseline, and had a Month 7 immunogenicity result. The registry record does not report how many participants met these criteria for each type, how missing measurements were handled, or what sensitivity analyses were performed. The representativeness and robustness of the per-protocol results therefore cannot be evaluated from the reported information.
The record lists 6 outcomes and 22 analyses but does not report a multiplicity strategy, the complete statistical plan, interim analyses, or the trial’s sample-size justification. It also does not give numerical results for the secondary seroconversion outcome. The selected safety information lacks a reported follow-up timeframe and additional detail about event-specific denominators. These reporting gaps limit interpretation of both the study’s statistical conclusions and its safety summaries.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Multivalent HPV (Human Papillomavirus) Vaccine Study in 16- to 26-Year Old Men and Women (V503-003) — NCT01651949.
- Registry record last updated 2018-11-27; status last verified 2018-10.
- Results first posted 2015-03-09.
- 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.
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18. Record Summary
NCT01651949 is a completed phase III, nonrandomized, unmasked, parallel-group study sponsored by Merck Sharp & Dohme LLC. The registry record reports enrollment of 2520, a start date of 2012-10-29, and a primary completion date of 2014-08-04.
Healthy females, heterosexual males, and MSM aged 16 to 26 years received 9vHPV vaccine on Day 1, Month 2, and Month 6. The primary outcome was GMT to the vaccine HPV types at Month 7, four weeks after the third vaccination. The stated primary question was whether responses in heterosexual males were non-inferior to those in young women, using a per-protocol analysis population.
The registry record lists seroconversion as a secondary outcome and reports selected safety counts. It does not report numerical GMT results, confidence interval limits, the non-inferiority margin, or the conclusion about the primary hypothesis. It also does not report the approach to multiplicity or missing data.