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 A Study of Belimumab in Chinese Pediatric Participants With Systemic Lupus Erythematosus (NCT05917288), a na phase 1 study. The primary outcome is Area Under the Curve at Steady-state to the End of the Dosing Period (AUCss,0-tau) of Belimumab for Participants Weighing Greater Than or Equal to (>=) 50 Kilograms (kg).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05917288 |
| Phase | Phase 1 |
| Condition | Systemic Lupus Erythematosus |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 16 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Chinese pediatric participants with systemic lupus erythematosus (SLE) who had completed 48 weeks of intravenous belimumab treatment in study 213560 (NCT04908865). The registry record lists enrollment of 16 participants. The primary pharmacokinetic measure described in the record applies to participants weighing greater than or equal to 50 kilograms; the number in that weight group is not reported in the registry record.
Intervention
Belimumab 200 milligrams per milliliter by subcutaneous injection, according to baseline body weight, together with standard of care (SOC). The study is described as open-label, so masking was not used.
Comparator
There was no separate control group. This was a single-group study with allocation listed as not applicable, so its results do not provide a like-for-like comparison between belimumab and another treatment or control condition.
Primary question
The primary pharmacokinetic question concerned belimumab exposure at steady state, measured by the area under the concentration-time curve over the dosing period (AUCss,0-tau), for participants weighing greater than or equal to 50 kilograms. The record also describes safety evaluation, including adverse events through Week 12. A numerical result for the primary endpoint is not reported in the registry record.
3. Trial Design
This was a Phase 1, multicentre, open-label, single-group study of subcutaneous belimumab plus standard of care in Chinese pediatric participants with SLE. The registry lists the study as completed, with a recorded enrollment of 16. The study began on 2023-07-07, and its primary completion date was 2024-10-30.
The registry summary describes participants as having completed 48 weeks of intravenous belimumab treatment in study 213560 (NCT04908865) before entering this study. In the study, participants received belimumab 200 milligrams per milliliter by subcutaneous injection according to baseline body weight, alongside standard of care. The record does not describe a separate untreated, placebo, or active-comparator group.
Because the study had a single group and no masking, the data are descriptive rather than a randomized comparison. The registry lists allocation as not applicable and masking as none. These design features mean that the record can describe the pharmacokinetic and safety observations among participants treated in the study, but it cannot isolate a treatment contrast against a concurrent control group.
The primary endpoint was a pharmacokinetic measure of belimumab exposure at steady state for participants weighing greater than or equal to 50 kilograms. Blood samples were collected at the specified pre-dose and post-dose times. The registry also lists adverse events, serious adverse events, and adverse events of special interest through Week 12 among secondary outcomes. The registry record does not report a protocol-level sample-size justification, details of an interim analysis, or a full statistical analysis plan.
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: Participants who had completed 48 weeks of intravenous (IV) belimumab treatment in study 213560 (NCT04908865) were enrolled in this study.
Overall Study
| Stage | Belimumab 200 mg/mL |
|---|---|
| STARTED | 16 |
| COMPLETED | 16 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: PK Analysis Set included all participants assigned treatment who received at least one dose of study treatment and for whom at least one post belimumab treatment PK sample was obtained and analyzed.
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 | Belimumab 200 mg/mL |
|---|---|---|
| Participants analysed | 16 | |
| Age, Continuous | YEARS | 12.9 (SD 2.55) |
| Sex: Female, Male: Female | Participants | 11 |
| Sex: Female, Male: Male | Participants | 5 |
| Race/Ethnicity, Customized: Asian - East Asian Heritage | Participants | 16 |
6. Primary Endpoint
The registry lists the primary outcome as Area Under the Curve at Steady-state to the End of the Dosing Period (AUCss,0-tau) of Belimumab for Participants Weighing Greater Than or Equal to (>=) 50 Kilograms (kg), measured over Pre-dose on Days 1, 8, and 78, and post-dose on Days 4, 81, and 85.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Geometric Coefficient of Variation |
| Unit | Days*micrograms per milliliter |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the area under the concentration-time curve at steady state over the dosing period (AUCss,0-tau) for belimumab among participants weighing greater than or equal to 50 kilograms. Its stated unit is days multiplied by micrograms per milliliter. The measure uses blood concentrations observed over time to characterize drug exposure across a dosing interval. In general, pharmacokinetic measures help describe how a drug is present in the body; they do not by themselves establish a clinical benefit.
The registry describes the endpoint as a geometric mean, with geometric coefficient of variation as its dispersion measure. A geometric mean summarizes values on a multiplicative scale and is commonly used for positively skewed pharmacokinetic measurements. The geometric coefficient of variation conveys relative variability on that scale. These are descriptive summaries, not a treatment-versus-control effect estimate.
Samples were scheduled pre-dose on Days 1, 8, and 78, and post-dose on Days 4, 81, and 85. The record notes that the first belimumab dose was administered on Day 1, so Week 12 post-dose corresponds to Day 85. The numerical AUC estimate and its geometric coefficient of variation are not reported in the registry record. The number of participants weighing at least the endpoint’s threshold is also not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a completed, single-group pharmacokinetic and safety study, not a randomized efficacy comparison. Its primary endpoint is belimumab exposure at steady state, summarized as a geometric mean AUC over the dosing period for participants weighing greater than or equal to 50 kilograms. However, the numerical endpoint estimate and its variability are not reported in the registry record. As a result, the posted information does not permit a quantitative reading of the observed exposure or its precision.
The record states that blood samples were collected at scheduled pre-dose and post-dose times. It defines the primary pharmacokinetic analysis population as participants who received at least one dose and had at least one post-treatment pharmacokinetic sample obtained and analyzed. The number meeting that definition is not reported in the registry record. Nor is the number of participants in the weight-defined primary endpoint group reported in the registry record.
For safety, the record lists 16 participants at risk for serious adverse events and zero participants with a serious adverse event. It lists 16 at risk for other adverse events and 13 with an event in that category; deaths are listed as zero. These are observed counts in this study group. Without a control group, they do not show how the counts would compare under another treatment or without study treatment. The record does not establish that any particular event was caused by belimumab.
The registry lists 13 outcome measures and zero analyses. That distinction matters: an outcome measure can be specified or reported without a corresponding statistical analysis being posted. There is no reported primary endpoint estimate, confidence interval, hypothesis-test result, or comparison effect in the registry record. Therefore, the record supports description of the study design and the listed safety counts, but not an assessment of the size or precision of the primary pharmacokinetic result.
Any sample-size illustrations associated with the posted material should be read as planning calculations, not as observed power or as the study’s original design justification. The stated illustration assumptions involve a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions do not describe this single-group study’s design. A sample-size calculation based on an observed effect cannot substitute for a reported result or establish the precision of the study’s endpoint.
9. Statistical Methods Explained
The main endpoint is pharmacokinetic, and the registry identifies its summary as a geometric mean with geometric coefficient of variation. General explanation: pharmacokinetic measurements describe drug exposure using concentrations observed across time. An area under the concentration-time curve combines concentration and time across a specified interval. AUCss,0-tau refers to exposure at steady state from the beginning to the end of the dosing period. This type of measure answers a different question from a clinical outcome such as symptom change.
Why use a geometric mean?
General explanation: positive pharmacokinetic measurements can have a right-skewed distribution, in which a small number of relatively high values extend the upper tail. A geometric mean summarizes values multiplicatively and is often more suitable than an arithmetic mean when the data are analyzed on a logarithmic scale. It is a descriptive measure of the group’s central exposure, not a measure of an individual participant’s response and not a comparison with an untreated group.
The registry pairs the geometric mean with a geometric coefficient of variation. General explanation: a coefficient of variation expresses variation relative to the scale of the measurements; its geometric form is used with log-scale summaries. It helps describe dispersion around pharmacokinetic values. The registry record does not report the numerical geometric mean or geometric coefficient of variation for the primary endpoint, so their magnitude and precision cannot be assessed from the posted results.
What does the sampling schedule contribute?
The record specifies blood collection pre-dose on Days 1, 8, and 78, and post-dose on Days 4, 81, and 85. It explains that the first dose was administered on Day 1 and that Week 12 post-dose corresponds to Day 85. In general, sampling at selected times allows the concentration-time profile and exposure over a dosing interval to be characterized. The schedule alone does not reveal the measured concentrations, the calculated AUC, or how complete the usable sampling data were. Those numerical details are not reported in the registry record.
Who is included in the pharmacokinetic analysis?
The registry defines the PK Analysis Set as participants assigned treatment who received at least one dose and had at least one post-belimumab-treatment pharmacokinetic sample obtained and analyzed. This definition focuses the analysis on participants with treatment exposure and usable post-treatment pharmacokinetic data. The registry record does not state how many participants met this definition, how many had data available at each sampling time, or whether any measurements were excluded. Missing-data handling is not reported in the registry record.
What can a single-group design establish?
General explanation: a single-group study can describe observations made under the study conditions, including pharmacokinetic measurements and recorded adverse events. Without a concurrent comparator, it cannot estimate a randomized between-group treatment effect. Open-label conduct also means treatment was not masked, although the registry record does not provide further detail about how that design feature affected outcome assessment. The study’s stated primary endpoint is an exposure measure, rather than a comparative clinical efficacy endpoint.
How should planning calculations be read?
The sample-size assumptions described for planning illustrations specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. General explanation: such calculations describe hypothetical future-study planning under chosen assumptions; they are not observed power. The stated two-arm allocation assumptions do not match this single-group study. The registry record does not report that these calculations formed part of the trial’s original design or sample-size justification.
Over-dispersion is a general concern when observed variability exceeds what a simple statistical model assumes. In general, ignoring extra variation can make uncertainty appear smaller than it is. The registry record does not state that over-dispersion was assessed or that any particular model was used to address it. No inferential analysis details, confidence intervals, or hypothesis tests for the primary endpoint are reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 13 outcome measures and zero analyses. The number of outcome measures alone does not establish how many were designated primary, how they were ordered, or whether formal hypothesis tests were planned. The record identifies the AUCss,0-tau measure as the primary outcome and lists adverse events, serious adverse events, and adverse events of special interest through Week 12 among secondary outcomes. A multiplicity strategy, such as a testing hierarchy or adjustment for multiple comparisons, is not reported in the registry record.
Missing-data methods are also not reported in the registry record. The defined PK Analysis Set requires at least one post-treatment pharmacokinetic sample to have been obtained and analyzed, but that definition does not specify how missing sample times or incomplete participant profiles were handled. The number of participants in the analysis set, the number with complete sampling, and any imputation or exclusion rules are not reported in the registry record.
The record does not provide a detailed statistical analysis plan, interim-analysis details, or confidence intervals and hypothesis tests for the primary endpoint. These omissions limit assessment of how the outcome measures were analyzed and how uncertainty or multiplicity was addressed. They should not be filled in by assuming conventional methods.
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 |
|---|---|---|---|
| Belimumab 200 mg/mL | 0 | 16 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Belimumab 200 mg/mL | 0 of 16 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Belimumab 200 mg/mL | 13 of 16 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Belimumab 200 mg/mL |
|---|---|---|
| Upper respiratory tract infection | Infections and infestations | 9 of 16 |
| Bronchitis | Infections and infestations | 3 of 16 |
| Hepatic function abnormal | Hepatobiliary disorders | 2 of 16 |
| Bacterial infection | Infections and infestations | 1 of 16 |
| Conjunctivitis | Infections and infestations | 1 of 16 |
| Mycoplasma infection | Infections and infestations | 1 of 16 |
| Tinea versicolour | Infections and infestations | 1 of 16 |
| Tonsillitis | Infections and infestations | 1 of 16 |
| Viral infection | Infections and infestations | 1 of 16 |
| Diarrhoea | Gastrointestinal disorders | 1 of 16 |
The registry lists 16 participants at risk for serious adverse events, with zero participants affected, and 16 at risk for other adverse events, with 13 affected. Deaths are listed as zero. The registry also lists no top serious-event terms. These counts describe what was recorded for the study group; they are not comparative risk estimates.
The serious-event count should be read separately from the count for other adverse events. A zero count for serious adverse events means none were listed among participants at risk in this record; it does not demonstrate that serious events are impossible or that the study can rule out uncommon harms. The count for other adverse events indicates that events in that category were recorded, but the registry summary does not provide their individual terms or severity in the listed safety details.
The secondary safety outcome specifies adverse events, serious adverse events, and adverse events of special interest through Week 12. The record does not report a causal assessment for the listed events. Because there was no comparator group, these counts cannot be used to estimate how safety would differ under another treatment or in the absence of study treatment.
12. What the Result Does, and Does Not, Mean
The record documents a completed Phase 1 study of subcutaneous belimumab plus standard of care in Chinese pediatric participants with SLE who had completed 48 weeks of intravenous belimumab treatment in another study. It identifies a pharmacokinetic primary endpoint and provides a definition of the analysis population and blood-sampling schedule. It also reports safety counts for serious and other adverse events and deaths.
The record does not report a numerical value for the primary AUC endpoint or its geometric coefficient of variation. It therefore does not show the magnitude of belimumab exposure measured in the primary endpoint group or the precision of that estimate. The number of participants in that weight-defined group and the number included in the PK Analysis Set are also not reported in the registry record.
The safety counts are descriptive observations in a single study group. They do not establish whether an event was caused by treatment, and they cannot provide a randomized comparison with another treatment or a control condition. The absence of a reported serious adverse event in this group should not be interpreted as proof that such events cannot occur.
The endpoint concerns drug exposure, not clinical improvement in SLE. The posted information does not provide a comparative clinical efficacy result. Taken together, the registry record describes the study’s design, intended pharmacokinetic assessment, and listed safety counts, while leaving the primary numerical pharmacokinetic result and several analysis details unreported.
13. Why This Trial Matters Statistically
This study is statistically distinct from a comparative efficacy trial. It is a Phase 1, open-label, single-group investigation focused on pharmacokinetics and safety after subcutaneous belimumab treatment in Chinese pediatric participants with SLE. Recognizing that design helps readers match the claims to the evidence: the record describes observations in treated participants, not a randomized contrast with another group.
The primary endpoint also illustrates why the type of outcome matters. AUC at steady state is a measure of drug exposure derived from blood concentrations over time. Its geometric summary and dispersion measure are designed to describe pharmacokinetic data, but they are not substitutes for clinical outcomes. The numerical primary result is not reported in the registry record, which means the central exposure estimate and its variability cannot be assessed from the posted information.
The study’s focus is additionally specific to a pediatric Chinese population described as having prior intravenous belimumab treatment. That context is important when interpreting what the study addresses: the registry does not describe an untreated population or a direct comparison of routes of administration. Its record lists safety counts, but without a concurrent comparator those counts remain descriptive.
For biostatistical interpretation, the distinction between a defined outcome, a reported estimate, and a reported analysis is consequential. The record identifies outcome measures and an analysis population definition, while listing zero analyses. Readers can understand the planned type of measurement and the reported safety counts, but cannot reconstruct an unreported endpoint estimate, uncertainty interval, or inferential analysis.
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 limitation for interpreting the posted pharmacokinetic result is that its numerical estimate and geometric coefficient of variation are not reported in the registry record. The record also does not state how many participants weighed greater than or equal to 50 kilograms or how many met the PK Analysis Set definition. Without those details, the size of the analyzed endpoint group and the estimate’s precision cannot be evaluated.
The single-group, open-label design has no concurrent comparator. Consequently, the study does not provide a randomized comparison of belimumab with another treatment or control condition. The record also does not report a clinical efficacy result, so the pharmacokinetic endpoint should not be read as a measure of clinical benefit.
Participants are described as having completed 48 weeks of intravenous belimumab treatment in another study. The findings therefore relate to the population and treatment context described in the registry, not necessarily to participants without that prior treatment history. The registry record does not provide further details about selection into this study or how that history affected the analysis.
Other limitations of the posted record include the absence of a reported statistical analysis plan, missing-data methods, multiplicity strategy, confidence intervals, and hypothesis tests. Safety counts are available, but the listed information does not include individual non-serious event terms or causal assessments. These limits constrain what can be concluded from the registry record; they should not be resolved by assuming unreported methods or results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Belimumab in Chinese Pediatric Participants With Systemic Lupus Erythematosus — NCT05917288.
- Registry record last updated 2025-11-14; status last verified 2025-10.
- Results first posted 2025-11-14.
- 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
The registry identifies NCT05917288 as a completed Phase 1, multicentre, open-label, single-group study of subcutaneous belimumab plus standard of care in Chinese pediatric participants with SLE. Enrollment is listed as 16. Participants are described as having completed 48 weeks of intravenous belimumab treatment in study 213560 (NCT04908865).
The primary endpoint is steady-state AUC over the dosing period for participants weighing greater than or equal to 50 kilograms, summarized by a geometric mean and geometric coefficient of variation. Blood-sampling times are specified, but the numerical primary endpoint result is not reported in the registry record. The record lists 13 outcome measures and zero analyses.
For safety, zero participants are listed with serious adverse events, 13 with other adverse events, and zero deaths. These are descriptive counts from a single group, not a comparative treatment effect.