A Study of E6011 in Japanese Subjects With Rheumatoid Arthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of E6011 in Japanese Subjects With Rheumatoid Arthritis (NCT02196558), a non-randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs).

2. Clinical Question

The clinical question is principally descriptive: what adverse events were recorded among participants receiving E6011 at each dose level? The registry describes the study as a multiple ascending dose study designed mainly to evaluate safety and tolerability of repeated subcutaneous administration. Its primary outcome is the number of participants with treatment-emergent adverse events and serious adverse events, with a timeframe of up to 52 weeks.

The study also lists positive anti-E6011 antibody results and serum concentrations of E6011 as secondary outcomes. The record does not provide results for those outcomes in the registry record described for this analysis. Nor does the primary outcome assess improvement in rheumatoid arthritis symptoms or disease activity. A measure of clinical benefit is not reported in the registry record among the outcome information.

Because allocation was non-randomized and there was no control arm, the results answer a different question from whether E6011 caused more or fewer events than an alternative treatment or no treatment. The counts describe the observed safety experience in the listed dose groups. They cannot isolate the effect of dose from other differences between participants or from changes over the course of the study.

3. Trial Design

The registry describes a Phase 1/2, multicenter, open-label, uncontrolled, multiple ascending dose study. It used a non-randomized, parallel-group design. Participants were Japanese subjects with rheumatoid arthritis. The registry lists enrollment of 53; its brief summary states that 33 subjects would receive repeated subcutaneous E6011. These are separate registry statements, and the record information does not explain their relationship.

The brief summary describes a 12-week treatment phase and a 40-week extension phase. It says the first 12 subjects would enroll in the 100 mg group, the next 12 in the 200 mg group, and the last 9 in the 400 mg group. Thus, the dose groups were enrolled in a fixed sequence rather than assigned at random. Participants and investigators were not masked, and there was no concurrent control group.

The arm descriptions specify subcutaneous administration at Week 0, 1, and 2, followed by administration every 2 weeks up to 10 weeks during the treatment phase. The administration volume and injection-site instructions differ by dose group. Participants who rolled over into the extension phase were to continue monitoring until 52 weeks after initial administration. The record says that subjects who intended to continue administrations could receive subsequent biweekly administrations, but the available arm descriptions are truncated and do not provide a complete account of the extension regimen.

The primary outcome is a participant count for treatment-emergent adverse events and serious adverse events, assessed up to 52 weeks. The safety analysis set is defined as participants who received at least 1 dose and had at least 1 postdose safety assessment. Listed secondary outcomes are positive anti-E6011 antibody results and serum concentrations of E6011. The registry record does not report a randomized efficacy comparison, masking procedures, or a separate control intervention.

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: Total 53 participants were enrolled and screened, of which 16 were screen failures, 37 participants received study drug in 12-week Treatment Phase. Out of them, 32 participants completed 12-week Treatment Phase. Of 32 participants, 28 participants entered Extension Phase, 22 completed 40-week Extension Phase. '\>='signifies greater than or equal to.

Treatment Phase (12 Weeks)

Reasons for not completing this period:

Extension Phase (40 Weeks)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The safety analysis set included group of participants who received at least 1 dose of study drug and had at least 1 postdose safety assessment.

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: The safety analysis set included group of participants who received at least 1 dose of study drug and had at least 1 postdose safety assessment.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs), measured over Up to 52 Weeks.

The primary endpoint counts participants with treatment-emergent adverse events and serious adverse events through up to 52 weeks. It is a count of participants with events, rather than a measure of event severity averaged across the group, an event rate per unit of time, or a measure of rheumatoid arthritis response. The safety analysis set includes participants who received at least 1 dose of study drug and had at least 1 postdose safety assessment.

Safety outcomes are central to a study described as evaluating safety and tolerability of repeated administration. Counting affected participants makes the occurrence of adverse events visible across the dose groups. Separating serious adverse events from other adverse events can also help readers distinguish events classified as serious from the broader set of reported events. Those categories should not be treated as interchangeable measures: seriousness is a classification, not simply a count of symptoms or an assessment of whether an event was caused by the study drug.

As a general statistical point, participant counts are easiest to interpret when the analysis population, observation period, and event definitions are clear. The registry identifies the safety population and gives an up-to-52-week timeframe, but the endpoint description does not include further detail about event ascertainment or attribution. A count alone does not show when an event occurred, how long participants were observed, or whether the event was related to treatment. Those details are not reported in the registry record.

The outcome is descriptive in this uncontrolled study. It can report what was observed among participants in each dose group, but it does not by itself estimate how those counts would compare with a control group.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary participant-level outcome in the sense that each participant is classified according to whether an event was recorded. The posted measure is a count of participants with events. A count is a direct description of the number of affected participants in a group; it is not itself a probability, a rate, or an estimate of a causal treatment effect. The group sizes are also relevant to interpreting counts, but comparisons require attention to the way participants entered the groups and the amount of follow-up available.

What does a participant count show?

A participant count tells readers how many people in the defined safety population had an event during the stated observation period. It does not indicate how many separate episodes each person experienced. Nor does it describe event timing, duration, severity beyond the serious-event classification, or treatment attribution. Where a person can experience more than one kind of event, event-term counts and counts of participants with any event are different summaries. The registry outcome is explicitly framed as the number of participants with events.

For interpretation, a count is most useful alongside a clear denominator and a consistent observation window. The record gives the group counts and describes the outcome timeframe as up to 52 weeks. It defines the safety analysis set as participants who received at least 1 dose and had at least 1 postdose safety assessment. The record information does not report each participant’s duration of observation or an exposure-adjusted event rate. As a general statistical matter, unequal time at risk can make raw counts difficult to compare: participants observed for longer have more opportunity for events to be detected.

Why does the study design matter?

Random allocation is a general method for balancing, on average, both known and unknown participant characteristics between treatment groups. This study was non-randomized. The brief summary describes sequential enrollment into the 100 mg, 200 mg, and 400 mg groups, so dose and enrollment order are linked by design. There was also no control group. As a result, differences in observed counts cannot be attributed to dose alone. Baseline differences, calendar or enrollment timing, follow-up, and other factors may also matter; the record does not provide an adjusted analysis addressing these possibilities.

Open-label means treatment assignment was not masked. That can matter in general because knowledge of treatment may affect reporting, monitoring, or assessment. The record does not describe procedures used to reduce such influences. This is a design consideration, not evidence that reporting was biased in this trial.

What would uncertainty estimates add?

A confidence interval is a general statistical way to express the uncertainty around an estimated quantity, such as an event proportion or a difference between groups. A wider interval indicates less precision, while a narrower interval indicates greater precision under the method’s assumptions. The registry record does not report confidence intervals or a comparative effect estimate for the primary outcome. Without those estimates, readers should not infer precision from the counts alone or treat apparent differences between groups as established differences in underlying risk.

Likewise, a significance test would address a specified statistical comparison under stated assumptions. The registry information reports no analyses for the primary outcome. There is therefore no reported p-value establishing a between-group difference. Even if a test were available, a statistical result would not resolve the non-randomized design’s limits or establish causation.

How should planning illustrations be read?

General sample-size planning asks how many participants per arm might be needed to detect a stated effect under specified assumptions. The planning description associated with this record uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; its target effect is expressed as a fraction of the observed effect. Such calculations are illustrations based on the stated assumptions, not the trial’s own design justification and not observed power. The registry record does not report the protocol’s sample-size justification. Planning values, if presented elsewhere with this record, should not be read as evidence that the study had a particular probability of detecting an effect after completion.

General sample-size calculations also depend on the endpoint and comparison being planned. A planning illustration based on a two-arm comparison does not turn the actual sequential, uncontrolled dose groups into a randomized comparison. It cannot correct for confounding, unequal exposure, or missing outcome information. The interpretation remains anchored to the design that was actually used.

Finally, multiplicity can arise when investigators evaluate several outcomes, groups, or comparisons. If many statistical tests are performed, the chance of at least one apparently notable result can increase unless the analysis plan accounts for this. The registry lists a primary outcome and secondary outcomes, but the analysis plan and any multiplicity strategy are not reported in the registry record. The posted counts can be read descriptively without assuming that an unreported testing strategy was used.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies the primary safety outcome and lists secondary outcomes for positive anti-E6011 antibody results and serum concentrations of E6011. The statistical analysis plan, including any planned comparisons or multiplicity adjustment, is not reported in the registry record. The outcome information includes no inferential analyses. It is therefore not possible to establish from this record whether additional outcomes or comparisons were tested, or how multiple testing was handled.

Missing-data methods are also not reported in the registry record. The safety analysis set is defined as participants who received at least 1 dose and had at least 1 postdose safety assessment. This definition clarifies who could be included in the safety summaries, but it does not describe how participants with incomplete follow-up were handled, whether all participants had observation through 52 weeks, or how missing event assessments were treated.

That distinction matters for a safety endpoint with a timeframe of up to 52 weeks. A participant with shorter observation may have less opportunity for an event to be recorded than a participant observed for longer. General methods can account for differing follow-up or missing information in different ways, but the registry record does not state that any particular method was used. The posted counts should therefore be read as the reported participant counts, not as estimates adjusted for missingness or exposure time.

The record names the safety analysis set but does not give additional analysis-population definitions for the secondary outcomes in the registry record. It also does not report the handling of participants who did not continue into the extension phase. Those details are important context for interpreting longer-term outcomes and should not be inferred from the stated observation timeframe.

11. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: carpal tunnel syndrome (10.0%), patella fracture (8.3%), facial paralysis (6.7%), latent autoimmune diabetes in adults (6.7%), breast cancer (6.7%).

The serious adverse event figures are participant counts within each listed group. The 100 mg group has 1 participant with a serious adverse event among 12 at risk; the 200 mg group has 3 among 15; and the 400 mg group has 1 among 10. The associated counts for other adverse events are 10 among 12, 13 among 15, and 7 among 10, respectively. The record lists 0 deaths for each group.

These counts do not mean that every participant had only one event. They count participants, rather than total episodes, and they do not show when events occurred. The registry’s primary outcome timeframe is up to 52 weeks, but follow-up duration by participant is not reported in the information. The groups therefore should not be compared as though each participant had identical time at risk.

The registry lists carpal tunnel syndrome (10.0%), patella fracture (8.3%), facial paralysis (6.7%), latent autoimmune diabetes in adults (6.7%), and breast cancer (6.7%) as leading serious adverse event terms. The record information does not give a denominator or dose-group breakdown for those term percentages. They are not a basis for assigning a term to a particular dose group or for concluding that an event was caused by treatment. Seriousness, occurrence, and treatment attribution are distinct concepts; attribution details are not reported in the registry record.

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

The result means that adverse events were recorded among participants in each of the listed dose groups during the study’s safety observation period. The registry reports serious adverse event counts, other adverse event counts, and no deaths in the groups. These are descriptive observations from a Phase 1/2, open-label, uncontrolled, non-randomized study.

The result does not establish that E6011 caused an event. Adverse events occurring during a study are not necessarily caused by the study drug, and the information does not report attribution assessments. It also does not establish that the dose groups had different underlying safety profiles. Participants entered groups sequentially, rather than by random allocation, and there was no control group. The counts do not adjust for participant characteristics, follow-up duration, or exposure.

The endpoint does not answer whether E6011 improves rheumatoid arthritis. The primary outcome counts adverse events, while the secondary outcomes listed concern anti-E6011 antibodies and serum concentrations. Results for those secondary outcomes are not reported in the registry record. A conclusion about clinical benefit cannot be drawn from the safety counts.

Nor should the absence of recorded deaths be read as proof that the risk of death is absent. It is a finding in the observed study groups, not a guarantee about outcomes in other participants or settings. Likewise, the serious-event term percentages listed in the registry are not directly comparable without a clear denominator, and the record information does not identify their dose-group distribution.

In general, a controlled randomized study can support a more direct comparison between treatment groups because randomization helps balance other influences. This study was not designed that way. Its counts are useful as a record of what was reported during the study, but they have limited ability to establish comparative effects or to separate treatment effects from other explanations.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of how safety data from an early-phase, ascending-dose trial must be interpreted in light of design. The outcome is a participant count, and the registry provides counts for serious and other adverse events in each dose group. Those summaries describe the observed safety experience without implying that the groups are comparable or that any observed event was caused by treatment.

The sequential enrollment scheme is central to interpretation. The 100 mg, 200 mg, and 400 mg groups were enrolled in order, and allocation was non-randomized. This means dose is entangled with enrollment sequence. A difference between the groups could reflect dose, participant mix, follow-up, or other differences. Without a control group and an adjusted comparative analysis, the counts do not provide a causal estimate of relative safety.

The record also illustrates why outcome definition and observation time matter. The endpoint counts participants with events up to 52 weeks, while the study includes a treatment phase and an extension phase. The registry identifies the safety analysis population, but the information does not report individual follow-up or how incomplete observations were handled. Counts alone cannot account for differences in time at risk.

Finally, the record separates a primary safety outcome from secondary antibody and concentration outcomes, yet it does not report the analysis plan or multiplicity handling. This is a reminder that the meaning of statistical evidence depends not only on the numerical result but also on how outcomes and comparisons were specified and analyzed. Here, the most defensible reading is descriptive: the reported counts document observed events in the study groups, with substantial limits 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 main trial-specific limitation is the absence of randomization and a control group. Participants entered the dose groups sequentially, so dose group is linked to enrollment order. The groups cannot be treated as like-for-like controls, and the observed counts cannot establish a causal dose effect or a comparison with usual care, placebo, or another treatment.

The study was open-label. The registry information does not report masking or other procedures intended to limit possible effects of treatment awareness on event reporting and assessment. This is a potential design consideration, not proof that reporting was affected.

The primary outcome is a count of participants with adverse events over a timeframe of up to 52 weeks. Participant-specific follow-up and exposure time are not reported in the information. Counts can therefore be difficult to compare if observation differed across participants. The registry defines the safety analysis set, but missing-data methods and handling of incomplete follow-up are not reported in the registry record.

The record does not report confidence intervals, comparative estimates, or inferential analyses for the primary outcome. Nor does the information report event attribution or a dose-group breakdown for the listed serious adverse event terms. The percentages associated with those terms lack a stated denominator in this record information.

The registry lists enrollment of 53, while the brief summary describes 33 subjects as receiving E6011. The record information does not explain the relationship between those statements. The planned group sequence in the summary also differs from the safety counts shown for the groups; the registry record does not explain this. These details should not be reconciled by assumption. Results for the listed secondary outcomes and the protocol’s sample-size justification are not reported in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study of E6011 in Japanese Subjects With Rheumatoid Arthritis — NCT02196558.
• Registry record last updated 2020-08-13; status last verified 2017-08.
• Results first posted 2020-08-13.
• 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

NCT02196558 is a completed Phase 1/2 study of repeated subcutaneous E6011 in Japanese subjects with rheumatoid arthritis. The registry describes a multicenter, open-label, uncontrolled, non-randomized, parallel-group, multiple ascending dose study. The brief summary describes a 12-week treatment phase and a 40-week extension phase.

The primary outcome is the number of participants with treatment-emergent adverse events and serious adverse events through up to 52 weeks. The safety analysis set includes participants who received at least 1 dose and had at least 1 postdose safety assessment. The posted group counts include serious adverse events in each dose group and no deaths in any group.

The study is descriptive rather than a randomized comparison. The registry lists positive anti-E6011 antibody results and serum concentrations of E6011 as secondary outcomes, but those results are not reported in the information. The analysis plan, missing-data methods, and protocol sample-size justification are not reported in the registry record.