Immunogenicity and Safety of Concomitant Administration of RotaTeq™ (V260) and the Diphtheria, Tetanus, Pertussis and Inactivated Poliovirus Vaccine (DTP-IPV) in Healthy Japanese Infants (V260-060): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Immunogenicity and Safety of Concomitant Administration of RotaTeq™ (V260) and the Diphtheria, Tetanus, Pertussis and Inactivated Poliovirus Vaccine (DTP-IPV) in Healthy Japanese Infants (V260-060) (NCT01926015), a randomized phase 4 study. The primary outcome is Percentage of Participants Achieving Seroresponse for Diphtheria Toxin, Tetanus Toxin, Pertussis Filamentous Hemagglutinin (FHA), and Poliovirus Type 1, 2, and 3.

2. Clinical Question

The primary endpoint was the percentage of participants reaching specified antibody thresholds for diphtheria toxin, tetanus toxin, pertussis toxin, pertussis filamentous hemagglutinin (FHA), and poliovirus types 1, 2, and 3. Serum was collected 4 to 6 weeks after the third DTP-IPV dose. A percentage above a threshold is a binary outcome for each antibody measure: each participant either met the prespecified response criterion or did not.

The comparison concerns the timing of the two vaccines, not whether either vaccine was given. In the concomitant group, both were administered together at the scheduled visits. In the staggered group, the RotaTeq™ visits and DTP-IPV visits were separated. The record does not report primary response percentages, a between-group difference, a confidence interval, or a test result. Therefore, the stated research question can be identified, but its answer cannot be determined from the registry results described.

3. Trial Design

This was a post-marketing, phase 4, randomized, open-label study with a parallel-group design. The registry lists an enrollment of 192 and a completed study. The study dates recorded are 2013-09-19 for the start and 2014-06-06 for primary completion. Participants were healthy Japanese infants, and the condition listed in the record is rotavirus disease.

The two groups differed in the timing of RotaTeq™ relative to DTP-IPV. In the concomitant group, RotaTeq™ (2 mL by mouth) and DTP-IPV (0.5 mL by subcutaneous injection) were administered together at Visit 2, Visit 4, and Visit 6. Visit 2 was at least 4 weeks after Visit 1; later visits were described as 6-8 weeks apart. In the staggered group, RotaTeq™ was administered at Visit 1, Visit 3, and Visit 5, while DTP-IPV was given at Visit 2, Visit 4, and Visit 6. The record describes Visit 1 as Day 1 and gives the same stated intervals for the subsequent visits.

Random allocation can help make groups comparable at the start of a study, while a parallel design assigns participants to one schedule rather than having each participant receive both schedules. Open-label means masking was not used, according to the registry. The record does not report further details about the allocation procedure, concealment, or any steps taken to reduce bias in outcome assessment.

The primary antibody endpoint was assessed in the per-protocol population, defined by receipt of the three scheduled DTP-IPV doses according to guidelines and the absence of an important protocol deviation that could substantially affect the endpoint. That definition is narrower than simply being enrolled. The registry record does not report the number of participants included in that primary analysis or provide a participant-flow account. It also does not report the protocol’s sample-size justification.

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: The per-protocol population included participants who received the 3 scheduled doses of DTP-IPV according to guidelines and did not have an important protocol deviation that may substantially affect the results of the endpoint

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 Percentage of Participants Achieving Seroresponse for Diphtheria Toxin, Tetanus Toxin, Pertussis Filamentous Hemagglutinin (FHA), and Poliovirus Type 1, 2, and 3, measured over 4 to 6 weeks after the third dose of DTP-IPV.

The primary endpoint is the percentage of participants who achieved seroresponse for the listed vaccine antigens. Seroresponse was defined using threshold antibody levels: diphtheria toxin at >=0.1 International Units (IU)/mL; tetanus toxin at >=0.01 IU/mL; pertussis toxin and pertussis FHA at >=10 Enzyme Units (EU)/mL; and poliovirus types 1, 2, and 3 at a neutralizing antibody (NA) titer >=8. Serum was collected 4 to 6 weeks after the third DTP-IPV dose.

For each antibody measure, this endpoint classifies participants according to whether their measured response reached the corresponding threshold. Reporting a percentage makes the result interpretable as the proportion of the analyzed group meeting that criterion. It does not, by itself, describe the full range of antibody concentrations or titers among participants.

Threshold-based response rates are useful for comparing groups when the study question concerns the proportion meeting defined antibody criteria. In this trial, the stated purpose was to assess whether response rates with concomitant administration were non-inferior to those with staggered administration. Assessing that claim requires the group results and an appropriate comparison against a prespecified non-inferiority margin. The margin, response percentages, comparison estimates, and confidence intervals are not reported in the registry record. The primary endpoint’s measurement rules are available, but the result cannot be interpreted as demonstrating or failing non-inferiority from those rules alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General: What does a percentage endpoint represent?

A percentage endpoint represents the share of participants who meet a defined outcome criterion. For this study, the criterion was an antibody level at or above a threshold for each specified antigen. A percentage is a binary summary: it records whether each participant crossed the relevant threshold, but it does not preserve all detail about the underlying antibody measurements. Two groups could have similar percentages while having different distributions of values above the threshold; conversely, small changes in measurements near the threshold could change whether individual participants count as responders.

The registry specifies that serum was collected 4 to 6 weeks after the third DTP-IPV dose. This timing anchors the endpoint to a defined period after vaccination. The record provides different numerical thresholds for the antibody measures and identifies the per-protocol population for the primary endpoint. The actual response percentages and participant counts analyzed for that endpoint are not reported in the registry record.

How should a confidence interval be read?

General: A confidence interval describes the uncertainty around an estimated quantity under the assumptions of the statistical method. For a between-group comparison, the estimate describes the observed contrast, while the interval indicates a range of values compatible with the data and method. A narrow interval generally indicates greater precision than a wide interval. An interval’s interpretation depends on what is being estimated and, for a non-inferiority question, on how it compares with the prespecified margin.

The registry record does not report a confidence interval for the primary endpoint, nor does it report an estimated between-group contrast or the non-inferiority margin. It is therefore not possible to discuss the precision of the primary comparison or determine whether its interval met a non-inferiority rule.

What is the role of randomization and masking?

General: Randomization assigns participants to groups using a chance-based procedure. When implemented appropriately, it can reduce systematic differences between groups at baseline, though it does not guarantee that every characteristic will be balanced. A parallel-group design compares groups assigned to different schedules over the study. Masking can reduce the influence of expectations on participant reporting, clinical assessment, or other study processes when it is feasible and appropriate.

The registry identifies this study as randomized, parallel, and open-label, with no masking. It does not report enough detail to describe the randomization sequence, allocation concealment, or specific procedures used to limit the consequences of open-label conduct. Those details are not reported in the registry record.

Why does the analysis population matter?

General: An analysis population determines which participants contribute to an estimate. A per-protocol analysis typically focuses on participants who followed specified study procedures, while an analysis of all randomized participants retains participants according to their randomized group even if some did not complete the planned regimen. These approaches can answer related but not identical questions. In non-inferiority studies, the choice and handling of analysis populations can be particularly important because exclusions or deviations may affect the comparison.

The primary endpoint population in this record was defined by receipt of the three scheduled DTP-IPV doses according to guidelines and absence of an important protocol deviation that may substantially affect the endpoint. The registry does not report how many participants met that definition, whether another analysis population was used for the primary endpoint, or how participants with missing measurements were handled.

What does non-inferiority mean statistically?

General: A non-inferiority analysis asks whether the data rule out a loss larger than a prespecified acceptable margin. It is not simply a search for a statistically significant difference between groups. The direction of the comparison, the definition of the effect measure, the margin, and the confidence interval all matter. A finding of no statistically significant difference under a superiority test does not, by itself, establish non-inferiority.

The registry states the non-inferiority hypothesis for antibody response rates, but does not report the margin, test procedure, estimated contrast, confidence interval, or primary result. The registry record therefore does not allow readers to reconstruct the decision rule or independently assess the claim.

How should planning illustrations be interpreted?

General: Sample-size planning explores how many participants might be needed to detect an assumed effect under specified statistical conditions. Such calculations depend on assumptions about the effect, significance level, allocation, and statistical approximation. A planning estimate is not an observed result, and it is not the probability that a completed study found an effect.

The record describes a planning illustration based on a stated fraction of an observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. It distinguishes participant counts per arm for most outcomes from total event counts for time-to-event outcomes. The registry record does not report the trial’s own sample-size justification, and numerical planning estimates are not available in the record described. These planning assumptions should not be mistaken for observed power or evidence about the primary endpoint.

General: In short, the endpoint definition tells readers what was measured; the analysis population identifies whose measurements were intended for the primary analysis; and the comparison estimate and its uncertainty are needed to evaluate the stated non-inferiority question. The registry record supplies the first two types of information in part, but does not report the primary comparison results needed for the final statistical interpretation.

10. Multiplicity, Missing Data and Analysis Populations

The record lists 13 outcome measures and 7 analyses. It identifies a primary endpoint covering seroresponse for multiple antibody measures, and it lists secondary outcomes covering adverse events and geometric mean titers. The registry does not report how the analyses correspond to all the outcome measures, or whether a formal procedure was used to address multiple comparisons. A multiplicity strategy, if any, is not reported in the registry record.

General: When a study evaluates multiple outcomes or performs multiple statistical tests, the chance of at least one apparently unusual result can increase if each test is interpreted separately without considering the number of comparisons. Methods to address this issue can include prespecifying a primary outcome, adjusting decision thresholds, or treating secondary analyses as exploratory. The appropriate approach depends on the trial question and analysis plan. The existence of several outcomes alone does not show that a multiplicity adjustment was required or omitted; the registry record does not report the relevant plan or results.

The registry defines the primary endpoint population as participants who received the three scheduled DTP-IPV doses according to guidelines and had no important protocol deviation that may substantially affect the endpoint. It does not report the number included in this population, the numbers excluded, or the reasons for exclusion. The handling of missing antibody measurements, missing safety observations, and incomplete follow-up is not reported in the registry record. Details about imputation, sensitivity analyses, or other missing-data methods are also not reported.

These gaps limit interpretation because analysis choices can affect the estimate and its uncertainty. Without the analysis plan, the primary results, and participant accounting, readers cannot determine how missing measurements or protocol deviations influenced the comparison, nor whether reported analyses followed a prespecified hierarchy. The registry information does not establish that such procedures were absent; it means they are not reported in the registry record.

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: pneumonia respiratory syncytial viral (1.0%), upper respiratory tract inflammation (1.0%).

The registry lists serious adverse events separately for the two study groups. In the concomitant group, 0 participants were reported as affected among 94 at risk. In the staggered group, 2 were reported as affected among 96 at risk. These are descriptive counts in the registry record; they are not a statistical comparison and do not include a reported confidence interval or test result.

The record also names pneumonia respiratory syncytial viral and upper respiratory tract inflammation as top serious adverse-event terms, each with a reported value of 1.0%. The listed information does not identify which group each term occurred in or provide further event-level details. Death counts are not reported in the registry record.

Other adverse events are listed for 57 participants among 94 at risk in the concomitant group and 79 among 96 at risk in the staggered group. The record does not provide a comparative estimate or uncertainty measure for these counts in the information described. Adverse-event counts should be read as observations within the recorded follow-up and definitions, not as proof that the schedules caused or prevented events. The record does not report enough detail to evaluate event timing, severity beyond the serious-event classification, or a causal relationship to vaccination.

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

The study was designed to compare antibody response rates after concomitant versus staggered administration of RotaTeq™ and DTP-IPV in healthy Japanese infants. Its stated primary question was whether the response rates with concomitant administration were non-inferior to those with staggered administration. The registry provides the endpoint thresholds and timing, but does not report the primary response percentages or the statistical comparison.

Accordingly, the record does not establish that the schedules had equivalent response rates, that one schedule had higher rates, or that the non-inferiority criterion was met. It also does not establish that the criterion was not met. Those conclusions require the group estimates, the relevant non-inferiority margin, and an uncertainty-based comparison, none of which are reported in the registry record.

The safety counts provide a limited descriptive account. The record lists serious adverse events in 0 participants among 94 at risk in the concomitant group and 2 among 96 at risk in the staggered group, along with selected serious-event terms. These figures should not be expanded into claims about causation or comparative safety without supporting analysis and context. The record also lists counts for other adverse events, but does not report an adjusted comparison or uncertainty for them.

More generally, an endpoint definition is not a result, and a result is not automatically a definitive conclusion. The measured percentages, study population, analysis method, missing-data handling, and uncertainty all contribute to interpretation. Because the primary results and several analysis details are not reported, the registry record supports an account of what the study intended to assess, but not a statistical verdict on its main hypothesis.

13. Why This Trial Matters Statistically

This trial raises a practical statistical question about comparing two schedules using threshold-based antibody response rates. The research question is framed as non-inferiority: the relevant aim is not simply to detect any difference, but to assess whether response rates under concomitant administration remain within an acceptable range relative to staggered administration. That distinction makes the prespecified margin and uncertainty around the comparison essential to interpretation.

The record also illustrates why endpoint definitions and endpoint results must be distinguished. It specifies the antibody thresholds and the time when serum was collected, which clarifies what counted as a response. However, without the response rates and comparative estimate, readers cannot assess the central statistical question. Detailed measurement definitions do not substitute for reported results.

The study’s randomized, parallel design is relevant because it compares separate groups assigned to different schedules. Its open-label status is also relevant when considering how outcomes and safety reports might be collected or assessed. The registry does not describe further safeguards or the allocation procedure, so readers should avoid assuming details not recorded.

Finally, the record shows the importance of transparent reporting of analysis populations, missing data, multiplicity, and safety comparisons. It defines a per-protocol population, but does not report its analyzed size or participant flow. It names multiple outcomes, but does not report a multiplicity approach. It lists selected safety counts, but does not give comparative uncertainty. These reporting elements help readers judge not only what was measured, but how firmly the reported evidence supports a conclusion.

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 central limitation for statistical interpretation is that primary endpoint results are not reported in the registry record. The record gives antibody-response thresholds and the assessment timeframe, but not the response percentages by group, the comparative estimate, a confidence interval, or the primary test result. The non-inferiority margin and the analysis procedure are also not reported. As a result, the stated primary hypothesis cannot be evaluated from the registry information described.

The record defines the per-protocol population but does not report its size, the number of participants excluded from that analysis, or participant flow through the study. Missing-data methods and sensitivity analyses are not reported. These omissions prevent assessment of how incomplete measurements or protocol deviations may have affected the endpoint estimates.

Although the study is identified as randomized and open-label, details about the randomization procedure, allocation concealment, and safeguards against bias are not reported in the registry record. The listed safety information includes group counts and selected serious-event terms, but does not provide event-level timing, arm assignment for the named terms, comparative uncertainty, or a causal assessment. Death counts are not reported.

The record lists secondary outcomes and analysis counts, but does not provide the full set of numerical results or explain how multiple analyses were handled. It also does not report the trial’s sample-size justification. These limitations concern what is available in the registry record; they do not establish that the underlying study documentation lacked such analyses or details.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Immunogenicity and Safety of Concomitant Administration of RotaTeq™ (V260) and the Diphtheria, Tetanus, Pertussis and Inactivated Poliovirus Vaccine (DTP-IPV) in Healthy Japanese Infants (V260-060) — NCT01926015.
• Registry record last updated 2018-11-14; status last verified 2018-10.
• Results first posted 2015-04-09.
• 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.

18. Record Summary

NCT01926015 is a completed, post-marketing, randomized, open-label, phase 4 parallel study in healthy Japanese infants. It compared concomitant with staggered administration of RotaTeq™ and DTP-IPV. The registry lists enrollment of 192 and records study start on 2013-09-19 and primary completion on 2014-06-06.

The primary endpoint was the percentage achieving specified antibody thresholds 4 to 6 weeks after the third DTP-IPV dose, assessed in a defined per-protocol population. The stated hypothesis was non-inferiority of antibody response rates with concomitant administration. The primary outcome estimates, non-inferiority margin, and statistical comparison are not reported in the registry record.

For serious adverse events, the record lists 0 affected participants among 94 at risk in the concomitant group and 2 among 96 at risk in the staggered group. It also lists selected serious-event terms and counts for other adverse events. The record does not report enough comparative analysis to support conclusions about differences between schedules.