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 Safety and Immunogenicity of New Formulations of GlaxoSmithKline Biologicals' DTPa-HBV-IPV/Hib Vaccine (GSK217744) (NCT01248884), a randomized phase 2 study. The primary outcome is Number of Seroprotected Subjects for Anti-diphtheria (Anti-D) and Anti-tetanus (Anti-T) Antibodies..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01248884 |
| Phase | Phase 2 |
| Condition | Tetanus, Poliomyelitis, Hepatitis B |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 721 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Healthy infants aged between and including 60 and 90 days at first vaccination were eligible according to the arm descriptions. The study evaluated them during a primary vaccination course. The immunogenicity analysis population is described as the According-To-Protocol cohort, including evaluable subjects who complied with the protocol and had immunogenicity and assay results for antibodies against at least one study vaccine antigen.
Intervention
One group received GSK217744 formulation A and another received GSK217744 formulation B. Each group received three doses co-administered with Prevenar 13® at 2, 3 and 4 months of age. The record identifies GSK217744 as a biological intervention.
Comparator
The comparator group received three doses of Infanrix hexa™ co-administered with Prevenar 13® at 2, 3 and 4 months of age. The record describes a randomized, double-masked, parallel-group study. It does not report the allocation ratio.
Primary question
The primary endpoint was the number of vaccinated subjects meeting the registry definition of seroprotection for both anti-diphtheria and anti-tetanus antibodies. Seroprotection required concentrations of at least 0.1 international units per milliliter for each antibody. The timeframe is recorded as At Month 0. Numerical results for this endpoint are not reported in the registry record, so the primary comparison cannot be described from the posted results.
3. Trial Design
This was a phase 2, randomized, double-masked, parallel-group study of new formulations of GlaxoSmithKline Biologicals' DTPa-HBV-IPV/Hib vaccine, identified as GSK217744. The registry lists enrollment as 721 and study status as completed. The recorded start date is 2010-12-09, and the primary completion date is 2012-01-05.
The arm descriptions specify three groups: GSK217744 formulation A, GSK217744 formulation B, and Infanrix hexa™. Infants in each group were to receive three doses, co-administered with Prevenar 13®, at 2, 3 and 4 months of age. The first vaccination was for subjects aged between and including 60 and 90 days. The record does not state the allocation ratio or provide further detail about the masking procedures.
The trial assessed immunogenicity and safety. The primary endpoint concerned seroprotection against diphtheria and tetanus. Secondary outcomes covered antibody concentrations or seropositivity for diphtheria, tetanus, pertussis, Haemophilus influenzae type b and pneumococcal antigens, as well as vaccine response to pertussis antigens and solicited local and general symptoms. The registry lists 17 outcome measures and 14 analyses.
Randomization is generally used to reduce systematic differences between treatment groups, while masking can reduce the influence of treatment knowledge on care, reporting, or assessment. Those are general features of these design choices, not evidence that all potential sources of bias were eliminated in this trial. The registry record does not describe the randomization procedure, masking implementation, or the planned statistical analysis in enough detail to assess them.
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 | GSK217744 Group 1 | GSK217744 Group 2 | Infanrix Hexa Group |
|---|---|---|---|
| STARTED | 240 | 242 | 239 |
| COMPLETED | 238 | 239 | 238 |
| NOT COMPLETED | 2 | 3 | 1 |
Reasons for not completing this period:
| Reason | GSK217744 Group 1 | GSK217744 Group 2 | Infanrix Hexa Group |
|---|---|---|---|
| Withdrawal by Subject | 1 | 3 | 1 |
| Adverse Event | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The analysis was performed on the According-To-Protocol cohort for immunogenicity, which included all evaluable subjects, who complied with the protocol, for whom immunogenicity data were available and for whom assay results were available for antibodies against at least one study vaccine antigen component after at least one vaccination.
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 | GSK217744 Group 1 | GSK217744 Group 2 | Infanrix Hexa Group | Total |
|---|---|---|---|---|---|
| Participants analysed | 240 | 242 | 239 | 721 | |
| Age, Continuous | Weeks | 9.7 (SD 1.36) | 9.8 (SD 1.29) | 9.7 (SD 1.21) | 9.73 (SD 1.29) |
| Sex: Female, Male: Female | Participants | 119 | 138 | 99 | 356 |
| Sex: Female, Male: Male | Participants | 121 | 104 | 140 | 365 |
| Race/Ethnicity, Customized: African heritage /African American | Participants | 1 | 0 | 1 | 2 |
| Race/Ethnicity, Customized: White - Arabic / north African heritage | Participants | 3 | 1 | 6 | 10 |
| Race/Ethnicity, Customized: White - Caucasian / European heritage | Participants | 144 | 148 | 140 | 432 |
| Race/Ethnicity, Customized: Unspecified | Participants | 92 | 93 | 92 | 277 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Seroprotected Subjects for Anti-diphtheria (Anti-D) and Anti-tetanus (Anti-T) Antibodies., measured over At Month 0.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts vaccinated subjects who met the registry definition of seroprotection for both anti-diphtheria (Anti-D) and anti-tetanus (Anti-T) antibodies. A subject qualified if both antibody concentrations were at least 0.1 international units per milliliter. The endpoint is recorded as a count of participants, with a timeframe of At Month 0.
This is a binary classification at the participant level: a subject either meets the stated threshold for both antibodies or does not. General statistical context: threshold-based endpoints can make results easier to interpret as the number of participants reaching a defined antibody level. They also discard some information about the actual measured concentrations; two subjects on the same side of the threshold may have different values, while subjects close to opposite sides are classified differently.
The registry record does not clarify how the At Month 0 timeframe relates to the scheduled doses at 2, 3 and 4 months of age. It also does not report the primary endpoint counts by group, a treatment contrast, or uncertainty estimates. Accordingly, the endpoint definition can be described, but the comparative immunogenicity result cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives the primary endpoint definition but does not give numerical primary outcome results. It defines seroprotection as meeting the antibody concentration threshold for both diphtheria and tetanus, and records the assessment timeframe as At Month 0. No group-specific counts, proportions, effect estimate, confidence interval, or significance test for this endpoint are reported in the registry record. The available information therefore does not establish the direction or precision of a comparison between GSK217744 and Infanrix hexa™.
The record lists a completed randomized, double-masked, parallel-group phase 2 study, with three vaccine groups and enrollment of 721. Those design features describe how the trial was organized, not what its primary immunogenicity results were. A trial's completion status does not itself indicate the outcome, and enrollment is not a substitute for the endpoint-specific analysis population or results.
For safety, the registry records serious adverse event counts of 9 among 240 subjects at risk in GSK217744 Group 1, 5 among 242 in GSK217744 Group 2, and 4 among 239 in the Infanrix Hexa Group. The listed serious adverse event terms include bronchiolitis at 1.7%, and pneumonia, amoebiasis, asphyxia, bronchospasm and interstitial lung disease at 0.4% each. These are descriptive registry figures. The record does not give a statistical comparison of serious adverse events between groups, nor does it explain whether the listed terms refer to subjects or events in a way that would support further interpretation.
General statistical context: a confidence interval describes the range of effect values reasonably compatible with the data under a specified analysis. Without an effect estimate and its uncertainty interval, readers cannot judge how precisely a between-group difference has been estimated. A significance test alone, if available, would not convey the size or clinical importance of an effect; neither a test nor an estimate is reported for the primary endpoint in the registry record.
The safety counts should likewise not be treated as proof of equivalence or a difference. In general, event counts can be informative for describing what was recorded, but sparse events may yield imprecise comparisons. No conclusion about relative safety or immunogenicity can be drawn from these registry entries alone. The posted results support a description of the trial design, endpoint definition, and recorded serious adverse events, while the primary comparative result remains unreported in the registry record.
9. Statistical Methods Explained
The study is classified as randomized, double-masked and parallel-group. These are design characteristics, not a complete statistical analysis plan. The registry record does not report the randomization method, the details of masking, or the planned model for comparing groups. It identifies the study as phase 2 and lists enrollment as 721.
What does the primary endpoint count?
The endpoint is a participant count. A vaccinated subject met the definition if anti-diphtheria and anti-tetanus antibody concentrations were each at least 0.1 international units per milliliter. In statistical terms, that rule turns measurements into a yes-or-no outcome for each subject, then counts subjects who satisfy the rule. The stated timeframe is At Month 0. The registry record does not explain the timing label in relation to the vaccination schedule.
General statistical context: for a binary outcome, a group result may be reported as a count or as a proportion of an analysis population. A comparison could then be expressed using a difference or another effect measure, with an uncertainty interval. Those are general ways of analyzing binary outcomes, not a description of an analysis reported for this endpoint. No group results or comparative estimate are included in the registry record.
What does the analysis population mean?
The primary endpoint description says the analysis was performed on the According-To-Protocol cohort for immunogenicity. It characterizes this cohort as including evaluable subjects who complied with the protocol, had immunogenicity data available, and had assay results for antibodies against at least one study vaccine antigen. This differs conceptually from simply using everyone enrolled: an according-to-protocol analysis is restricted by evaluability and protocol compliance as described in the record. The registry does not report the size of this cohort by group or explain how exclusions were handled.
General statistical context: analyses restricted to participants with evaluable data can be affected if inclusion depends on factors related to treatment assignment or outcome. An analysis population definition helps readers understand who contributes to an estimate, but the definition alone does not show whether missing measurements or protocol deviations could have influenced results.
How should the safety counts be read?
The serious adverse event figures are counts of affected subjects and the corresponding numbers at risk for each group: 9 of 240 for GSK217744 Group 1, 5 of 242 for GSK217744 Group 2, and 4 of 239 for the Infanrix Hexa Group. They are descriptive counts. The record does not report a comparative model, an adjusted analysis, or uncertainty estimates for these figures. Deaths are not reported in the registry record.
General statistical context: event counts can vary by chance, especially when events are uncommon. A comparison that accounts for uncertainty is needed to assess how compatible the observed group differences are with a range of possible underlying effects. The registry figures alone do not provide that assessment. Over-dispersion is a general issue in count data when variability exceeds what a chosen model expects; it matters if such a model is used, but the record does not report a count model or enough information to assess over-dispersion for this trial.
What analysis details are absent?
The registry lists 17 outcome measures and 14 analyses, but does not report the statistical methods used for the primary endpoint, the handling of missing data, or a plan for multiplicity across outcomes. It does not report an interim analysis plan, sample-size justification, or inferential results for the primary endpoint. These details are not reported in the registry record; their absence should not be filled by assuming a conventional method.
General statistical context: a prespecified analysis plan helps distinguish planned tests from analyses chosen after observing the data. Confidence intervals, model assumptions, and the exact analysis population all affect interpretation. Since those details are unavailable for the primary result, the registry information allows the endpoint rule and broad design to be described, but not a statistical reconstruction of the immunogenicity comparison.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 17 outcome measures and 14 analyses. It does not report whether the analyses were organized into a hierarchy, whether a primary comparison was protected from testing across multiple outcomes, or whether any adjustment for multiplicity was planned. A multiplicity strategy is not reported in the registry record.
General statistical context: when many outcomes or comparisons are examined, the chance of at least one apparently unusual result can increase if each is assessed independently. Prespecified priorities or adjustments can help readers interpret such results. This general issue cannot be quantified for this trial from the registry entries, and no unreported plan should be assumed.
The primary endpoint description identifies an According-To-Protocol cohort for immunogenicity. It includes evaluable subjects who complied with the protocol and had immunogenicity data and assay results for antibodies against at least one study vaccine antigen. The record does not give the number analyzed in each group, the number excluded, or the reasons for missing endpoint data.
Missing-data methods, including any imputation or sensitivity analyses, are not reported in the registry record. General statistical context: missing measurements can affect a comparison if their occurrence is related to treatment group or the unobserved outcome. Reporting how much information is missing, why it is missing, and how analyses account for it helps readers judge robustness. Those details cannot be assessed from the registry information available.
The record also does not say whether the primary endpoint was analyzed in any population other than the stated according-to-protocol cohort. The relationship between the 721 enrolled subjects and the analysis population is not reported in the registry record. As a result, the completeness and scope of the primary immunogenicity analysis remain unclear.
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 |
|---|---|---|---|
| GSK217744 Group 1 | 9 | 240 | 3.8% |
| GSK217744 Group 2 | 5 | 242 | 2.1% |
| Infanrix Hexa Group | 4 | 239 | 1.7% |
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 |
|---|---|
| GSK217744 Group 1 | 240 of 240 |
| GSK217744 Group 2 | 239 of 242 |
| Infanrix Hexa Group | 235 of 239 |
Most frequent serious adverse event terms
| Event term | Organ system | GSK217744 Group 1 | GSK217744 Group 2 | Infanrix Hexa Group |
|---|---|---|---|---|
| Bronchiolitis | Infections and infestations | 4 of 240 | 0 of 242 | 3 of 239 |
| Pneumonia | Infections and infestations | 1 of 240 | 1 of 242 | 1 of 239 |
| Amoebiasis | Infections and infestations | 1 of 240 | 0 of 242 | 0 of 239 |
| Asphyxia | Respiratory, thoracic and mediastinal disorders | 1 of 240 | 0 of 242 | 0 of 239 |
| Bronchospasm | Respiratory, thoracic and mediastinal disorders | 1 of 240 | 0 of 242 | 0 of 239 |
| Gastrooesophageal reflux disease | Gastrointestinal disorders | 0 of 240 | 1 of 242 | 0 of 239 |
| Haemangioma of skin | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 240 | 1 of 242 | 0 of 239 |
| Interstitial lung disease | Respiratory, thoracic and mediastinal disorders | 1 of 240 | 0 of 242 | 0 of 239 |
| Pyelonephritis | Infections and infestations | 0 of 240 | 1 of 242 | 0 of 239 |
| Respiratory tract congestion | Respiratory, thoracic and mediastinal disorders | 1 of 240 | 0 of 242 | 0 of 239 |
Most frequent non-serious adverse event terms
| Event term | Organ system | GSK217744 Group 1 | GSK217744 Group 2 | Infanrix Hexa Group |
|---|---|---|---|---|
| Irritability | General disorders | 197 of 240 | 205 of 240 | 191 of 238 |
| Drowsiness | General disorders | 188 of 240 | 185 of 240 | 171 of 238 |
| Pain | General disorders | 190 of 240 | 183 of 240 | 155 of 238 |
| Fever | General disorders | 180 of 240 | 173 of 242 | 140 of 239 |
| Redness | General disorders | 151 of 240 | 140 of 240 | 128 of 238 |
| Loss of appetite | General disorders | 135 of 240 | 127 of 240 | 112 of 238 |
| Swelling | General disorders | 124 of 240 | 122 of 240 | 115 of 238 |
| Nasopharyngitis | Infections and infestations | 53 of 240 | 64 of 242 | 51 of 239 |
| Injection site induration | General disorders | 22 of 240 | 14 of 242 | 25 of 239 |
| Upper respiratory tract infection | Infections and infestations | 14 of 240 | 21 of 242 | 15 of 239 |
Serious events with the highest arm-level rate: bronchiolitis (1.7%), pneumonia (0.4%), amoebiasis (0.4%), asphyxia (0.4%), bronchospasm (0.4%).
The registry reports serious adverse events for each study group as affected-subject counts alongside the number at risk: 9 of 240 in GSK217744 Group 1, 5 of 242 in GSK217744 Group 2, and 4 of 239 in the Infanrix Hexa Group. These are the figures recorded for the serious adverse event summary; the registry does not provide a comparative statistical analysis or uncertainty intervals for them.
The listed serious adverse event terms and percentages are bronchiolitis at 1.7%, and pneumonia, amoebiasis, asphyxia, bronchospasm and interstitial lung disease at 0.4% each. The registry record does not provide further detail in the available information about the basis for each term-specific percentage or whether a subject could contribute to more than one term. Deaths are not reported in the registry record; that is not the same as a documented zero count.
General statistical context: adverse event counts describe what was recorded during the study, while a comparative safety conclusion requires attention to exposure, definitions, follow-up, and statistical uncertainty. The registry entries do not provide enough information to make that assessment. The counts should therefore be read descriptively, not as proof of a difference or similarity between groups.
12. What the Result Does, and Does Not, Mean
The record establishes that the trial was designed to evaluate safety and immunogenicity of two GSK217744 formulations in a primary infant vaccination course, with Infanrix hexa™ as the comparator and Prevenar 13® co-administered in all groups. It defines a primary seroprotection endpoint based on anti-diphtheria and anti-tetanus antibody concentrations and records the assessment timeframe as At Month 0.
What the record does not establish is the primary endpoint result. Numerical group results, an effect estimate, uncertainty intervals, and a statistical test are not reported in the registry record. Without these, readers cannot determine whether the observed seroprotection counts differed between groups, how large a difference might be, or how precisely any comparison was estimated.
The serious adverse event counts are available and can be described by group, as can the listed serious event terms. They do not, by themselves, establish that one group had greater or lesser safety risk. General statistical context: a failure to report a comparative result is not evidence that groups are equivalent, just as a numerical difference in descriptive counts does not by itself establish a real underlying difference.
The trial's randomized, double-masked design and completed status are relevant context, but they do not replace outcome reporting. The registry record also leaves aspects of the analysis unclear, including missing-data handling, multiplicity procedures, and the relationship between enrollment and the immunogenicity analysis cohort. These gaps limit interpretation of both the endpoint and the safety summaries.
Accordingly, the posted information supports an account of the trial question, study groups, endpoint definition, and selected safety counts. It does not support a conclusion about the comparative immunogenicity result or a treatment effect. No medical advice or claim about whether a vaccine works follows from the information recorded.
13. Why This Trial Matters Statistically
This study illustrates why a clinical trial record needs more than a design label and an endpoint definition to support statistical interpretation. The record describes a randomized, double-masked, parallel-group phase 2 trial and specifies a participant-level seroprotection rule for anti-diphtheria and anti-tetanus antibodies. Those details identify what the primary outcome was intended to represent, but without group results they do not show the observed comparison.
The endpoint also shows how a continuous measurement can be converted into a binary classification. General statistical context: a threshold can create a clear operational definition, but it can conceal differences in the underlying antibody concentrations and make classifications sensitive to values near the cutoff. Knowing the threshold is useful; knowing the distribution of the measurements and the group results would be necessary for fuller interpretation.
The study also offers a reminder that safety summaries and immunogenicity outcomes answer different questions. The serious adverse event counts describe recorded events, while the primary endpoint concerns antibody-based seroprotection. Neither can substitute for the other, and descriptive safety counts alone do not provide a comparative safety analysis.
Finally, the record lists multiple outcomes and analyses but does not report the multiplicity strategy, missing-data handling, or primary endpoint estimates. General statistical context: transparent reporting of analysis populations, uncertainty, and planned comparisons helps readers distinguish what was measured from what can be concluded. In this case, the available details permit a careful description of design and endpoint construction, while the absence of primary results puts a firm limit on comparative interpretation.
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 registry record does not report numerical results for the primary endpoint, including group-specific seroprotection counts, comparative estimates, or uncertainty intervals. Its timeframe is stated as At Month 0, but the record does not clarify how that label relates to vaccination at 2, 3 and 4 months of age. This limits interpretation of when the primary measurement occurred.
The immunogenicity analysis population is described as the According-To-Protocol cohort, but group-specific analysis counts and reasons for exclusions are not reported in the registry record. Missing-data methods and sensitivity analyses are also not reported. The stated enrollment of 721 therefore cannot be taken as the denominator for the primary outcome.
The registry lists 17 outcome measures and 14 analyses, but does not report a multiplicity plan or the statistical methods used for the primary comparison. The sample-size justification and interim analysis procedures are not reported in the registry record. The allocation ratio and detailed randomization and masking procedures are also not stated.
For safety, the record gives serious adverse event counts, but no comparative analysis or uncertainty estimates. It does not report deaths, which should not be interpreted as a confirmed absence of deaths. The available term-specific percentages are not accompanied by enough detail to establish their precise denominators or how multiple terms were handled.
These limitations concern what can be interpreted from the registry record. They do not establish that analyses or procedures were absent from the underlying study; those details are simply not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Immunogenicity of New Formulations of GlaxoSmithKline Biologicals' DTPa-HBV-IPV/Hib Vaccine (GSK217744) — NCT01248884.
- Registry record last updated 2018-08-20; status last verified 2014-07.
- Results first posted 2014-06-06.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
NCT01248884 is a completed phase 2 randomized, double-masked, parallel-group study sponsored by GlaxoSmithKline. The registry lists enrollment of 721, a start date of 2010-12-09, and a primary completion date of 2012-01-05.
The study compared GSK217744 formulation A and formulation B with Infanrix hexa™ in primary infant vaccination. Each group received three doses co-administered with Prevenar 13® at 2, 3 and 4 months of age. The primary endpoint counted subjects meeting the stated anti-diphtheria and anti-tetanus seroprotection threshold; its timeframe is recorded as At Month 0.
The registry reports serious adverse event counts by group but does not report numerical primary endpoint results or a comparative immunogenicity estimate. Several analysis details, including multiplicity procedures and missing-data handling, are not reported in the registry record.