A Study of MabThera (Rituximab) in Patients With Rheumatoid Arthritis Who Have Had an Inadequate Response to a Single Anti-TNF Inhibitor: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of MabThera (Rituximab) in Patients With Rheumatoid Arthritis Who Have Had an Inadequate Response to a Single Anti-TNF Inhibitor (NCT02079532), a na phase 3 study. The primary outcome is Change From Baseline to Week 24 in Disease Activity Score Based on 28-Joint Count (DAS28).

2. Clinical Question

This is a question about change over time within a treated group, rather than a direct comparison of rituximab with another treatment or with no treatment. The study enrolled 302 participants and is listed as Phase 3. Its summary describes patients who had an inadequate response to a single anti-TNF alpha inhibitor, with previous inadequate response categorized by the prior agent. The record does not provide numerical outcome results for those categories, so no subgroup pattern can be described.

The primary endpoint focuses on the mean change in DAS28 through Week 24. That change can describe how the measured disease-activity score shifted during the study, but a single-group change does not isolate the effect of treatment from other influences over time. The record does not report a numerical mean change, standard deviation, confidence interval, or inferential test for this endpoint. As a result, the clinical question is identifiable, but its quantitative answer cannot be read from the registry record.

3. Trial Design

The registry lists this as a Phase 3, open-label, single-group study of rituximab (MabThera) in people with rheumatoid arthritis following an inadequate response to one anti-TNF agent. Masking is listed as none, and allocation is listed as NA. The study is therefore not described as a randomized comparison, and it has no registered concurrent comparator arm. Its design cannot support a like-for-like comparison between rituximab and a control treatment.

The study summary says MabThera-naive participants were to be stratified according to inadequate response to etanercept, infliximab, or adalimumab. It describes treatment with rituximab on day 1 and day 15 while participants continued basic methotrexate therapy. The arm description identifies Rituximab + MTX. The registry record does not report separate outcome estimates for the prior-agent categories, nor does it clarify whether those categories were analyzed as separate groups.

The enrollment is 302. The study is marked completed, with a start date of 2006-11 and a primary completion date of 2010-11. The summary describes an anticipated time on study treatment of 2+ years, but this does not give the follow-up duration for each participant or establish how long the primary endpoint was followed. Those details are not reported in the registry record.

The primary endpoint is change from baseline to Week 24 in DAS28, summarized as a mean with standard deviation. The registry lists 19 outcome measures and zero analyses. It does not report the numerical primary outcome or a statistical analysis plan. Thus the design and endpoint are described, but the record does not provide enough outcome information to assess the size or precision of the observed change.

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: Intent to Treat (ITT) population: all participants who signed informed consent, received at least 1 dose of study drug, and where DAS28 was measured at least once under study medication (Weeks 8, 16, or 24 or unscheduled or withdrawal visit up to Week 24); those with no RA or no DAS28 score at screening were excluded, regardless if treated or not.

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: Safety population: all participants who received at least 1 dose of trial medication and had at least 1 safety follow-up.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline to Week 24 in Disease Activity Score Based on 28-Joint Count (DAS28), measured over Week 24.

The primary endpoint is change from baseline to Week 24 in the Disease Activity Score based on 28-joint count (DAS28). The score combines swollen and tender joint counts, erythrocyte sedimentation rate, and the participant’s global assessment of disease activity. The registry describes transformed scores ranging from 0 to 10, with higher scores indicating greater disease activity.

Because this is an endpoint of change, it concerns the difference between a participant’s baseline score and the score at Week 24, rather than the Week 24 score alone. The registry specifies that the outcome is summarized as a mean and standard deviation. A mean change describes the group’s average direction and magnitude of change; the standard deviation describes how spread out individual changes are around that average. These are complementary summaries and should not be treated as interchangeable.

DAS28 is used to summarize several aspects of rheumatoid arthritis disease activity in one measure. The registry describes a DAS28 score of 3.2 or less as low disease activity, and scores greater than 3.2 to 5.1 as moderate to high disease activity. Those categories concern score levels. They do not, by themselves, determine how large or meaningful a change from baseline is.

The numerical mean change and standard deviation for Week 24 are not reported in the registry record. Consequently, the direction, magnitude, and precision of the primary endpoint cannot be evaluated from the registered results.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change represent?

The primary endpoint is a continuous measure summarized by its mean change from baseline to Week 24. In general, a mean is the arithmetic average of the observed values in an analysis group. For a change endpoint, each included participant’s follow-up score is compared with that participant’s baseline score, and the group mean summarizes those changes. The mean can be useful for describing the overall direction and typical size of change, but it does not show how each participant changed.

The standard deviation (SD) is a measure of spread among the individual changes. A smaller SD indicates that the changes are more clustered around the mean, while a larger SD indicates more dispersion. The SD describes variation among observations; it is not itself a measure of how precisely the mean has been estimated. The registry specifies mean and SD as the summary statistics but does not report their values for the primary endpoint.

How should uncertainty be assessed?

In general, a confidence interval gives a range of values compatible with the data under the assumptions of the analysis. It communicates uncertainty around an estimate and is more informative about precision than a point estimate alone. A narrow interval indicates greater precision than a wide interval, although interpretation also depends on the endpoint and study design. No confidence interval for the primary change is reported in the registry record.

A p-value, when reported, addresses how compatible the observed data are with a specified null hypothesis under the analysis assumptions. It does not measure the size or clinical importance of an effect, and it does not remedy the absence of a control group. The registry does not report a primary-outcome p-value or statistical test. Statistical significance therefore cannot be assessed from this record.

What does the study design allow?

This trial is listed as single-group, open-label, and without masking. In a single-group study, the primary change can describe the observed trajectory in the treated group. It does not estimate a between-group treatment contrast because no concurrent comparison group is registered. A before-and-after difference is not equivalent to a randomized treatment effect: changes over time can have multiple explanations. This is a general distinction in trial interpretation, not a claim about what caused any unreported changes in this study.

Open-label conduct means participants and study personnel were not masked to treatment assignment, and masking is recorded as none. For an endpoint that includes a participant global assessment, awareness of treatment may be relevant to measurement and interpretation. The registry does not report safeguards, blinded outcome assessment, or procedures that would clarify how such influences were addressed.

What is the analysis population?

The primary-outcome description names an Intent to Treat (ITT) population. It defines this as participants who signed informed consent, received at least 1 dose of study drug, and had DAS28 measured at least once under study medication at specified study visits or qualifying visits through Week 24. This is the registry’s stated definition; it should not be silently replaced by a different convention. The subsequent wording about exclusions is incomplete, ending with “scree,” so the full eligibility and exclusion rules are not reported in the registry record.

The number of participants included in that analysis population is not reported. Enrollment does not establish how many contributed a Week 24 change value, since the endpoint-specific definition requires post-treatment measurement and the record does not state how missing measurements were handled.

What do the planning illustrations mean?

The study record includes assumptions for sample-size planning illustrations: a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of the observed effect. These are planning assumptions, not a description of this trial’s registered design. The trial itself is single-group and has no like-for-like control arm. Any such hypothetical planning outputs must therefore be read as illustrations for a proposed two-arm design, not as observed power for this study.

Sample-size calculations based on an observed effect depend on that effect estimate and on the assumptions used for the hypothetical comparison. They do not establish that the trial was designed with a particular power, nor do they prove that an effect is real. The registry does not report the trial’s own sample-size justification, and no numerical planning estimates are included in the registry record for interpretation.

What remains unavailable?

The registry lists 19 outcome measures and zero analyses. It does not report an analysis plan, a method for estimating uncertainty, adjustment variables, handling of repeated measurements, or methods for missing data. These omissions prevent a detailed appraisal of how the primary estimate was produced. General statistical principles can explain what a mean, SD, confidence interval, and p-value would mean, but they cannot supply the missing study results or analysis choices.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Rituximab + MTX")
n   <- c(291)
m   <- c(-1.56)
sp  <- c(1.4)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Rituximab + MTX  291  -1.560  1.400  -1.722  -1.398

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 19 outcome measures, with the primary endpoint identified as change in DAS28 from baseline to Week 24. Other listed outcomes include DAS28 scores, EULAR response, low disease activity, remission, response by EULAR category, HAQ-DI, FACIT-F, and SF-36 physical and mental composite scores. The record does not report which secondary outcomes, if any, were treated as confirmatory or how the outcomes were ordered for interpretation.

When a study examines multiple outcomes or performs multiple statistical tests, the chance of at least one apparently notable result can increase. In general, multiplicity procedures can control that risk, or investigators can define a hierarchy of outcomes before analysis. Whether either approach was used is not reported in the registry record. No inference about adjustment or lack of adjustment should be made from the list of outcomes alone.

The primary-outcome description gives an ITT population definition requiring at least 1 dose of study drug and at least one DAS28 measurement under study medication. It also contains an incomplete phrase about participants with no RA or no DAS28 score. The full analysis-population rules are therefore not reported. The number analyzed for the primary endpoint is not reported either.

Missing-data methods are not reported in the registry record. It is unknown how missing baseline or Week 24 measurements were handled, whether all available measurements were used, or whether any sensitivity analyses were performed. This matters because an estimate based only on participants with observed follow-up can be affected if missingness is related to outcomes or participant characteristics. That is a general concern, not evidence that missing data biased this study’s results. With no numerical estimate, analysis count, or missingness description, the robustness of the primary result cannot be assessed.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: musculoskeletal and connective tissue disorders (3.0%), infections and infestations (2.3%), injury, poisoning and procedural complications (2.3%), gastrointestinal disorders (1.7%), cardiac disorders (1.0%).

The safety record lists a Rituximab + MTX group with 302 participants at risk for serious adverse events and 36 affected. It also lists 302 at risk for other adverse events and 62 affected. These are the registry’s reported counts; they should not be converted into percentages without the relevant analysis details. The record does not clarify whether the affected counts refer to participants with at least one event or how repeated events were counted.

The serious-event terms with the highest listed percentages are musculoskeletal and connective tissue disorders (3.0%), infections and infestations (2.3%), injury, poisoning and procedural complications (2.3%), gastrointestinal disorders (1.7%), cardiac disorders (1.0%), and general disorders and administration site conditions (0.7%). The registry does not state the denominator or counting convention for these category percentages in the information available. Categories can overlap for an individual, so they should not be added together to infer a total.

Deaths are listed as null, which means a death count is not reported in the registry record. The figures describe reported safety outcomes in the treated group; without a control group they do not establish comparative risk or causation. The record does not provide enough information to infer whether an event was caused by treatment.

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

The registry record establishes the setting and question of the study: an open-label, single-group evaluation of rituximab with methotrexate in people with rheumatoid arthritis after an inadequate response to one anti-TNF inhibitor. It identifies change in DAS28 from baseline to Week 24 as the primary endpoint and describes the score’s components and direction. These details help define what the study was intended to measure.

The record does not report the numerical primary outcome. There is no mean change, SD, confidence interval, or p-value available. Consequently, it is not possible to state whether the group’s DAS28 score increased or decreased, how large any change was, or how precisely it was estimated. The absence of a result in the registry is not evidence that there was no change; it is a limitation of the available record.

Even if a numerical before-and-after change were available, the single-group design would limit causal interpretation. A change during follow-up would describe what happened among treated participants, but without a concurrent comparison group it could not isolate treatment effects from other influences. The open-label design also means treatment was not masked, a consideration for outcomes that include participant assessment.

The registry lists multiple secondary outcome domains and safety counts, but it does not provide numerical results for the clinical outcomes. The available safety figures describe affected counts and selected serious-event categories in the treated group. They do not establish comparative safety or prove that treatment caused a reported event. Deaths are not reported.

Accordingly, the defensible interpretation is limited to the study design, outcome definitions, and safety information recorded. Claims about efficacy, lack of efficacy, statistical significance, clinical importance, or comparative benefit and harm are not supported by the numerical results available in the registry record.

14. Why This Trial Matters Statistically

This study is a useful example of the distinction between a clearly described outcome and a reported outcome estimate. The registry identifies DAS28 change through Week 24 as the primary measure and explains what the score contains. Yet without the mean change and its variability, readers cannot assess either the observed magnitude or its precision. An endpoint definition is not a substitute for results.

The design also highlights why a within-group change and a treatment comparison answer different questions. A single-group study can describe the course of measured outcomes among participants receiving treatment. It cannot, by itself, establish what would have happened to comparable participants under a different treatment or no treatment. This is especially important when interpreting changes over time as evidence of a treatment effect.

The record’s safety information illustrates a separate reading issue: counts, event categories, and category percentages may use different counting conventions. Without further definitions, percentages across categories should not be added, and affected counts should not automatically be read as total event counts. A missing death count is not equivalent to a reported count of zero.

Finally, the registry lists many outcome measures but no analyses. That gap limits assessment of multiplicity, missing-data handling, and the consistency of results across outcomes. These are general statistical concerns that become important when interpreting a broad set of endpoints, but the record does not establish which methods were used. The trial therefore offers a clear lesson in separating design and measurement information from the statistical evidence needed to evaluate results.

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 principal limitation for interpreting the registered results is that the numerical primary endpoint is not reported. The record gives the outcome definition and summary measure but no mean change, standard deviation, confidence interval, or test result. The enrollment figure does not identify how many participants contributed to the Week 24 analysis, and the endpoint-specific analysis population is not fully described.

The study is single-group and open-label, without a registered concurrent comparator. This limits causal interpretation of any change over time and prevents a direct estimate of comparative effects. Because DAS28 includes a participant global assessment, lack of masking is also relevant to how the measurement may be interpreted, although the registry does not describe the assessment procedures in detail.

The study summary describes stratification by the prior anti-TNF agent, but the registry does not report separate results for those categories or clarify the role of that stratification in analysis. The primary population description ends with incomplete wording, leaving some eligibility and exclusion details unclear. The anticipated treatment duration in the summary does not specify actual participant-level follow-up.

Other limitations include the absence of a reported statistical analysis plan, missing-data methods, multiplicity approach, and numerical results for the listed secondary outcomes. The safety record does not report deaths, and the counting conventions for adverse-event categories are not fully specified. These gaps constrain interpretation; they do not establish that any particular bias or adverse outcome occurred.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of MabThera (Rituximab) in Patients With Rheumatoid Arthritis Who Have Had an Inadequate Response to a Single Anti-TNF Inhibitor — NCT02079532.
• Registry record last updated 2016-07-29; status last verified 2016-06.
• Results first posted 2015-06-09.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT02079532 is a completed Phase 3, open-label, single-group study of rituximab (MabThera) with methotrexate in rheumatoid arthritis following an inadequate response to one anti-TNF inhibitor. Enrollment is 302. The registry lists no masking and no allocation to a concurrent comparison group.

The primary endpoint is mean change from baseline to Week 24 in DAS28, summarized with a standard deviation. The record describes the score and its direction but does not report a numerical primary result. It lists 19 outcome measures and zero analyses. The available safety record reports 36 affected for serious adverse events and 62 affected for other adverse events, with 302 at risk in each listing; deaths are not reported.

Interpretation is limited by the absence of numerical efficacy results, incomplete analysis-population wording, and unreported missing-data and multiplicity methods. The single-group design also does not support a direct treatment comparison.