A Study of DS-7011a in Patients With Systemic Lupus Erythematosus: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of DS-7011a in Patients With Systemic Lupus Erythematosus (NCT05638802), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Treatment-emergent Adverse Events Following Administration With DS-7011a in Participants With Systemic Lupus Erythematosus.

2. Clinical Question

The clinical question is framed around safety in a small randomized study, while the broader trial objectives also included pharmacokinetics and proof of biological activity. The registry describes cutaneous lupus activity, overall lupus disease activity, and clinician- and patient-reported impressions among the secondary outcomes. Those objectives should be distinguished from the primary endpoint: the primary endpoint counts participants with treatment-emergent adverse events, and does not itself establish whether disease activity changed.

The registry record does not post a numeric comparative estimate, confidence interval, or p-value for the two groups. It also does not report a specific efficacy result in the registry record for this analysis. Therefore, the central question answered by the posted primary counts is descriptive: how many participants in each reported safety group had at least one treatment-emergent adverse event during the stated follow-up period.

3. Trial Design

This was a Phase 1b/2, randomized, double-blind, placebo-controlled, parallel-arm study sponsored by Daiichi Sankyo. Its official title describes exploration of safety, pharmacokinetics, and proof of biological activity in participants with systemic lupus erythematosus. The listed condition is systemic lupus erythematosus; the arm descriptions specify participants with systemic lupus erythematosus and cutaneous lupus erythematosus.

The study began on 2023-06-07, had a primary completion date of 2025-04-01, and is listed as completed. Registry enrollment is 26. The DS-7011a arm description specifies 20 mg/kg by intravenous infusion every 4 weeks. The placebo arm received placebo by intravenous infusion every 4 weeks. The registry identifies random allocation, double masking, and a parallel-arm model. Further details about the randomization process, masking procedures, treatment duration beyond the outcome timeframe, and any dose-escalation or cohort structure are not reported in the registry record.

The primary endpoint was the number of participants with treatment-emergent adverse events from the first dose through Week 24. Safety events were assessed in the Safety Analysis Set. The posted group counts are 11 of 19 for DS-7011a and 4 of 6 for placebo. These are reported as counts of participants, not as an adjusted treatment effect. The registry lists 13 outcome measures and 12 posted secondary outcomes, including pharmacokinetic parameters and measures of skin and overall lupus activity. Although the trial had those broader objectives, the available primary result is a safety outcome.

The record does not report the protocol’s sample-size justification, the intended analysis plan, or whether any interim analyses were planned. The outcome group counts also differ from the registry enrollment figure, and a reason for that difference is not reported in the registry record. Those gaps limit reconstruction of the trial’s conduct from the registry entry alone.

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: Safety events were assessed in the Safety Analysis Set.

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.

Population: Demographic and baseline characteristics were assessed in the Safety Analysis Set.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment-emergent Adverse Events Following Administration With DS-7011a in Participants With Systemic Lupus Erythematosus, measured over Post first dose up to Week 24.

The primary endpoint counts participants who had at least one treatment-emergent adverse event after the first dose and through Week 24. The registry defines these events as new adverse events arising after the first dose, or events already present before dosing that worsened in severity after treatment began. The endpoint is reported in units of participants, with safety assessed in the Safety Analysis Set.

A participant count is useful for describing how many people in each group experienced an event under the study’s definition. It is distinct from an event count: a person with multiple events remains one participant in this endpoint. The posted result gives 11 participants in the DS-7011a group and 4 in the placebo group. It does not give an adjusted comparison, a confidence interval, or a test of the difference between groups.

In a trial with safety as a central objective, tracking adverse events can help characterize the observed safety experience during the specified follow-up. However, a count alone does not describe the kinds, severity, duration, or relationship to treatment of all events, and it does not establish causation. The registry separately reports serious adverse events, which should not be conflated with the broader treatment-emergent adverse-event endpoint. This primary endpoint is not a direct measure of whether lupus symptoms or disease activity improved.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: each participant is counted as having or not having a treatment-emergent adverse event under the registry definition. The result is expressed as a count of participants rather than a continuous measurement such as a laboratory value. The reported counts are 11 participants for DS-7011a and 4 for placebo, with group sizes of 19 and 6, respectively. No additional calculation is needed to describe those observations, and the registry does not post a numeric comparative analysis for this endpoint.

What does a participant count capture?

A participant-level count answers whether a person experienced at least one qualifying event during the stated timeframe. It does not tell how many total events occurred, whether one person had several events, or how long an event lasted. The definition includes both newly occurring events and pre-existing events that worsened after dosing began. Consequently, the count is tied to this operational definition and to the observation period from the first dose through Week 24.

A group count should be interpreted alongside its denominator. The numerator represents participants with an event, and the denominator represents participants in the reported safety group. The record states that safety events were assessed in the Safety Analysis Set. It does not explain the difference between registry enrollment of 26 and the outcome group sizes of 19 and 6. Reasons such as withdrawal, exclusions, or incomplete reporting should not be presumed; the reason is not reported in the registry record.

Why is uncertainty important?

In general, an observed count is one realization from the experience of the enrolled participants. A confidence interval, when reported, describes a range of values compatible with the data under a specified statistical procedure. It helps communicate precision and is not a guarantee that the true value lies in that range. The registry does not report confidence intervals for the primary outcome, so the precision of any between-group effect cannot be assessed from a posted interval.

For a binary outcome, analysts may compare proportions or use other methods suited to event counts. The choice can matter, especially when groups are small or event counts are sparse. General methods may rely on approximations that work better under some data conditions than others; exact or model-based alternatives have different assumptions. The registry does not report which comparison method, if any, was prespecified or used for this endpoint. No p-value or adjusted estimate is posted, and none should be inferred from the raw counts.

What do the planning illustrations represent?

Sample-size calculations are planning tools. The registry’s stated planning assumptions describe an illustration based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. For time-to-event outcomes, the stated convention is a total event count; for other outcomes, the convention is participants per arm. These calculations are not observed power and do not show the probability that this completed trial detected an effect.

A planning illustration is conditional on its assumptions about the effect to detect, allocation, and statistical approximation. It should not be mistaken for the trial’s original design justification. The protocol’s sample-size rationale is not reported in the registry record. In addition, the primary comparison is identified as not estimable from the available binary endpoint data, so no numeric planning result should be used to imply a demonstrated treatment effect or adequate power for this trial.

How should safety results be separated?

The primary treatment-emergent adverse-event outcome is broader than serious adverse events. A serious adverse event is a separate safety classification, and the registry reports serious-event counts by group. The presence of a serious event does not mean that all participants in the group had an event; conversely, the absence of a serious event in a reported group does not mean that no non-serious adverse events occurred. The primary endpoint and serious-event summaries therefore answer different descriptive questions.

In general, a careful interpretation distinguishes counts, estimates, and tests. Counts describe observed participants. An estimate summarizes a target quantity, such as a treatment-group contrast. A confidence interval describes uncertainty around an estimate under its method, and a p-value summarizes compatibility of data with a specified null model under assumptions. Here, only the primary group counts are posted; the registry does not report a comparative estimate, confidence interval, or p-value. The record also does not report enough analysis details to reconstruct such quantities reliably.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("DS-7011a", "Placebo")
n      <- c(19, 6)
events <- c(11, 4)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  DS-7011a  19  11  57.9  33.5  79.7  36.3  76.9  36.1  76.9
ARM  Placebo  6  4  66.7  22.3  95.7  30.0  90.3  29.0  90.1

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 13 outcome measures, including 12 secondary outcomes. Those secondary outcomes cover pharmacokinetic parameters, cutaneous lupus activity, overall lupus disease activity, and clinician- and patient-reported impressions. When a study evaluates several outcomes, the chance of obtaining at least one apparently notable result can increase if many tests are conducted. General statistical approaches to this issue include prespecifying a primary outcome, adjusting tests, or treating secondary analyses as exploratory. The strategy used for this study is not reported in the registry record.

The registry entries list 0 analyses. This means the record does not post analysis results for those outcomes in the available entry; it does not establish whether analyses were never conducted. Numeric results for the secondary outcomes are not reported in the registry record. The record also does not report a hierarchy among secondary outcomes, a multiplicity adjustment, or whether the secondary outcomes were intended as confirmatory or exploratory.

Missing-data handling is another important part of interpreting a randomized trial. The primary outcome reports 19 participants in the DS-7011a group and 6 in placebo, while registry enrollment is 26. The reason for the difference is not reported in the registry record. The record does not explain whether participants without outcome data were excluded, whether any outcomes were imputed, how withdrawals were handled, or whether follow-up differed by group. No assumptions about missing participants or their outcomes can be made from the counts alone.

The endpoint description identifies the Safety Analysis Set as the population used for safety assessment. Additional definitions of that population, including its membership and handling of participants with incomplete follow-up, are not reported in the registry record. The statistical analysis plan and any sensitivity analyses are also not reported. As a result, readers cannot determine how robust the posted counts are to alternative assumptions about missing information or multiple outcomes.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

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: systemic lupus erythematosus (16.7%).

The serious adverse event summary reports 0 affected participants among 19 in the DS-7011a group and 1 among 6 in the placebo group. No deaths are listed in either group. These are participant counts, not counts of all individual serious-event episodes, and the registry does not provide a full narrative account of the events in the registry record for this analysis.

The registry lists systemic lupus erythematosus as a top serious-event term at 16.7%. The record does not provide enough context in this summary to interpret that percentage as an arm-specific risk or to determine the details behind the event classification. The serious-event count in the placebo group is one participant, but a term listing alone does not establish the clinical course, cause, or relationship to study treatment.

Serious adverse events are distinct from the broader primary endpoint of treatment-emergent adverse events. The primary outcome reports 11 participants with events in the DS-7011a group and 4 in placebo. These broader counts do not mean that all recorded events were serious. Conversely, the small serious-event counts should not be read as proof that serious events cannot occur. In general, rare or infrequent events are difficult to characterize precisely in small studies. The figures describe the registry’s recorded experience in these groups and do not establish comparative safety in a wider population.

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

The result means that the registry recorded treatment-emergent adverse events in 11 participants in the DS-7011a group and 4 participants in the placebo group during the stated period from the first dose through Week 24. The reported group sizes were 19 and 6, respectively, and safety was assessed in the Safety Analysis Set. The record also reports 0 serious adverse event participants in the DS-7011a group, 1 in placebo, and no deaths.

These observations do not establish that DS-7011a caused or prevented any particular event. Randomization supports a structured comparison, but causal interpretation still depends on the conduct and analysis of the trial, including outcome completeness and the statistical method. The registry does not post a comparative effect estimate, confidence interval, or p-value for the primary endpoint. Therefore, the observed counts do not establish a statistically supported difference between groups.

The counts also do not establish whether the treatment altered lupus activity. The registry lists secondary outcomes concerning cutaneous and systemic disease activity, pharmacokinetics, and global impressions, but numeric results for these outcomes are not reported in the registry record. The trial’s stated objectives include pharmacokinetics and proof of biological activity; the available primary result remains a safety count.

In general, a small study can provide descriptive information about events among enrolled participants while leaving substantial uncertainty about event frequency in a broader population. The reported placebo group is particularly small, and the overall enrollment is 26. The reason the group sizes reported for the primary outcome differ from registry enrollment is not reported in the registry record. The result should therefore be understood as a limited account of the safety observations available in the entry, not as a definitive estimate of comparative risk, efficacy, or long-term outcomes.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between a trial’s broad objectives and the result actually posted for its primary endpoint. The trial was designed to explore safety, pharmacokinetics, and proof of biological activity, while its primary outcome counts participants with treatment-emergent adverse events. That endpoint can describe safety experience, but it cannot answer every question about biological activity or clinical response.

The randomized, double-blind, placebo-controlled, parallel-arm design provides a framework for comparing groups. Yet a design label does not supply the missing ingredients for inference: the registry record does not post a comparative estimate, uncertainty interval, p-value, or analysis method for the primary result. This makes the distinction between descriptive results and inferential claims especially important. A reader can accurately report the posted participant counts without implying that a treatment difference has been demonstrated.

The size and completeness of the analyzed groups also matter. Registry enrollment is 26, while the reported safety groups comprise 19 and 6 participants. The reason is not reported in the registry record. Without knowing how those populations were formed or how missing outcomes were handled, readers cannot fully assess potential effects of incomplete follow-up or exclusions.

Finally, the listed secondary outcomes create a multiplicity question: the study includes pharmacokinetic and disease-activity measures in addition to its safety endpoint. The record does not report how those outcomes were analyzed together or whether any adjustment was planned. For clinical researchers, the key statistical lesson is to distinguish endpoint definitions, available counts, uncertainty, and unreported analysis choices. Such distinctions allow a restrained reading of a completed study without overextending what its registry results establish.

15. 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 result is limited by the absence of a posted comparative analysis for the primary binary endpoint. It gives participant counts but no treatment-effect estimate, confidence interval, p-value, or statistical method. The record identifies the endpoint as not estimable for a two-arm comparison from the available binary data. As a result, the posted counts support description but not a quantified inferential comparison.

The reported outcome group sizes are 19 for DS-7011a and 6 for placebo, while enrollment is listed as 26. The reason for this difference is not reported in the registry record. It is also not reported how participants with missing safety information, withdrawal, or incomplete follow-up were treated. The Safety Analysis Set is named, but its detailed definition is not reported.

The registry lists 12 secondary outcomes and 13 outcome measures overall, but numeric secondary results are not reported in the registry record. The analysis plan, multiplicity strategy, missing-data approach, and any interim analyses are also not reported. The study’s sample-size justification is not reported, so the planning assumptions should not be interpreted as the original design rationale. The study duration beyond the primary safety timeframe, detailed exposure, and event-level descriptions are not available in the registry record. These limitations prevent a complete assessment of precision, outcome completeness, and the relationship between the posted safety findings and broader clinical or biological outcomes.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of DS-7011a in Patients With Systemic Lupus Erythematosus — NCT05638802.
• Registry record last updated 2026-05-28; status last verified 2026-05.
• Results first posted 2026-05-28.
• 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.

19. Record Summary

NCT05638802 is a completed Phase 1b/2 randomized, double-blind, placebo-controlled, parallel-arm study sponsored by Daiichi Sankyo. It enrolled 26 participants with systemic lupus erythematosus; the arm descriptions specify systemic lupus erythematosus and cutaneous lupus erythematosus. The study began on 2023-06-07, and its primary completion date was 2025-04-01.

The primary endpoint was the number of participants with treatment-emergent adverse events from the first dose through Week 24. The registry reports 11 of 19 participants in the DS-7011a group and 4 of 6 in the placebo group. Serious adverse events were reported for 0 of 19 and 1 of 6, respectively, with no deaths listed. The registry lists 13 outcome measures, including 12 secondary outcomes, but does not report numeric results for those secondary outcomes in the available record. A formal comparison for the primary endpoint and the relevant analysis details are not reported.