A Non-Interventional Study of Rheumatoid Arthritis Patients Treated With RoActemra/Actemra (Tocilizumab) in Monotherapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Non-Interventional Study of Rheumatoid Arthritis Patients Treated With RoActemra/Actemra (Tocilizumab) in Monotherapy (NCT01705730), a registered phase not stated study. The primary outcome is Percentage of Participants on Tocilizumab Treatment at Month 6 After Treatment Initiation.

2. Clinical Question

The question is descriptive: among the participants included in the defined analysis population, how many were still receiving tocilizumab at the specified follow-up point? A percentage can describe treatment continuation in the study group, but by itself it cannot show what would have happened to the same participants under another treatment or without treatment. Because treatment was prescribed by physicians and no control group is described, differences in participants’ clinical circumstances and care may influence both treatment decisions and observed outcomes.

The registry also lists secondary questions about systemic manifestations, prior response or intolerance to other therapies, addition or use of disease-modifying antirheumatic drugs, and dose reductions. These topics describe treatment history and management in the study. Their numerical results are not reported in the registry record. The clinical question is therefore clear in its intended focus, while the posted record does not provide the endpoint estimate needed to quantify the answer.

3. Trial Design

Mon-ACT is described as a multi-center, non-interventional study of people with rheumatoid arthritis treated with tocilizumab monotherapy. Hoffmann-La Roche is listed as the sponsor. The study status is completed, with a start date of 2012-07-31 and a primary completion date of 2014-12-12. The registry lists an enrollment of 71.

Participants received tocilizumab according to individualized physician-prescribed regimens. The registry summary states that eligible participants initiated treatment according to the licensed label and were to be followed for 6 months in routine clinical practice. As a non-interventional study, the record does not describe investigators assigning participants to treatment arms. Allocation is not stated, and no randomized comparator is described. The single listed group is tocilizumab.

The primary endpoint is the percentage of participants on tocilizumab at Month 6 after treatment initiation. Its stated population is the full analysis set, defined as all participants who received at least one dose during the study. The number in that population is not reported in the registry record. The record does not describe the detailed data-collection schedule, the criteria used to determine treatment status at Month 6, or how follow-up ended for participants who stopped treatment or could not be assessed.

Thirty-five outcome measures are listed, alongside secondary questions concerning clinical manifestations, prior treatment response or intolerance, additional disease-modifying antirheumatic drugs, and dose changes. The registry record lists no analyses. A protocol, detailed statistical analysis plan, sample-size justification, and interim-analysis plan are not reported in the registry record. The stated 6-month follow-up describes the study’s intended observation period; it does not establish that every enrolled participant completed follow-up.

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: A total of 71 participants were enrolled in the study. Out of 71 participants, 68 received at least one dose of tocilizumab during the study and were included in the full analysis set.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full analysis set included all participants that received at least one dose of tocilizumab during the study.

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: Full analysis set included all participants that received at least one dose of tocilizumab during the study.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Participants on Tocilizumab Treatment at Month 6 After Treatment Initiation, measured over Month 6 after treatment initiation.

The primary endpoint is the percentage of participants who were on tocilizumab treatment at Month 6 after treatment initiation. It is intended to describe treatment continuation at a defined follow-up point. For this endpoint, the registry defines the full analysis set as participants who received at least one dose of tocilizumab during the study. The number of participants meeting that definition is not reported in the registry record.

A percentage is useful for expressing how common a binary status is in a specified population. Here the status is whether a participant was on treatment at Month 6. It does not, on its own, explain why treatment continued or stopped, or distinguish clinical, personal, or administrative reasons. Those reasons are not reported in the registry record.

The endpoint title and its stated timeframe are present, but the numerical percentage and its 95% confidence interval are not reported in the registry record. Without those values, the observed continuation proportion and its precision cannot be described. The endpoint also has no comparator in the record, so it cannot estimate a difference in continuation between treatment strategies.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary: at Month 6, each participant is classified according to whether they are on tocilizumab treatment. A percentage summarizes the share of the defined population with that status. This type of measure is often useful when the question concerns the frequency of a yes-or-no outcome at a specified time. The registry record does not report the observed percentage, so the value cannot be interpreted.

The record names a 95% confidence interval as the measure of dispersion for the primary endpoint. In general, a confidence interval communicates the uncertainty around an estimate: it gives a range of values compatible with the data under the statistical method used. A narrower interval generally indicates greater precision, while a wider interval indicates less precision. The interval itself, the endpoint estimate, and the method used to calculate it are not reported in the registry record. No numerical precision assessment is therefore possible.

The stated full analysis set includes all participants who received at least one dose of tocilizumab during the study. This is the population specified for the primary endpoint, but its size is not reported in the registry record. The registry enrollment is 71; that figure alone does not establish how many participants received a dose or were assessed at Month 6. The record does not describe whether participants with missing Month 6 status were excluded, counted in a particular category, or handled through another method.

In general, missing outcome data can affect a percentage because the result depends on which participants contribute to its numerator and denominator. If participants without an assessment differ from those with an assessment, a complete-case estimate may not represent the full intended population. Other missing-data approaches make different assumptions and can produce different estimates. The registry record does not report the extent of missing primary outcome data or any approach to handling it.

The study is described as non-interventional, with treatment prescribed by physicians. In general, this design can describe care and outcomes in a clinical-practice setting. It does not create randomized groups, and treatment decisions may be related to participant characteristics or clinical circumstances. Without a suitable comparison and an analysis plan addressing relevant differences, an observed outcome in a treated group should not be interpreted as a causal treatment effect. No adjusted analysis is listed in the registry record.

The registry lists 35 outcome measures and zero analyses. In general, assessing many outcomes can raise multiplicity concerns: the more statistical questions examined, the greater the chance that at least one finding appears notable by chance if each is tested separately. Methods such as prespecified outcome hierarchies or adjustments can address particular multiplicity problems, but the choice depends on the study’s aims and analysis plan. The registry record does not report a multiplicity strategy, a statistical analysis plan, or outcome-specific results. It is therefore not possible to assess whether any such approach was planned or used.

The posted safety counts concern participants at risk and participants affected. General interpretation of event counts requires attention to the population at risk, the event definition, and the period over which events were observed. These details help distinguish a count of participants with events from a count of separate events. The record reports 68 at risk and 3 affected by serious adverse events in the tocilizumab group, and 68 at risk and 0 affected for other adverse events. It does not report a death count.

Sample-size planning and observed results answer different questions. In general, planning calculations use assumptions about the outcome, target effect, significance level, and desired power to estimate how many participants might be needed for a planned comparison. They do not show that a study had that power after its results are known. The registry text describes an illustrative planning framework using a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects expressed as fractions of an observed effect. The record does not report numerical planning estimates, the observed primary effect, or a trial-specific sample-size justification. Since no comparator is described, that generic two-arm planning framework should not be mistaken for the design of this study.

The registry identifies the primary endpoint and its analysis population, but does not post the estimate, confidence interval, analysis details, or missing-data methods needed to reproduce or evaluate the statistical result. Statistical interpretation is therefore limited to the design and definitions that are recorded.

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("Tocilizumab")
n      <- c(68)
events <- c(54)
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  Tocilizumab  68  54  79.4  67.9  88.3  68.4  87.3  68.3  87.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 35 outcome measures and zero analyses. It identifies a primary endpoint and several secondary topics, including systemic manifestations of rheumatoid arthritis, prior intolerance or inadequate response to disease-modifying antirheumatic drugs, response to other biologics, use or addition of disease-modifying antirheumatic drugs, dose reductions, and treatment history. Numerical results for these outcomes are not reported in the registry record.

When multiple outcomes are examined, multiplicity can affect how statistical evidence should be interpreted. In general, testing many hypotheses without a prespecified strategy can increase the chance of at least one apparently notable result arising by chance. The registry record does not report whether outcomes were tested, whether a hierarchy or adjustment was planned, or how any multiplicity issue was addressed. It also does not provide p-values or analyses to evaluate.

The primary analysis population is defined as participants who received at least one dose of tocilizumab. Its size is not reported in the registry record. The record does not state how many participants had a Month 6 assessment, whether any outcome data were missing, or what method was used to handle missing data. In general, missingness matters because the denominator and the characteristics of assessed participants can affect an outcome percentage.

The analysis plan, including any interim analyses and the approach to missing data, is not reported in the registry record. Without those details or posted outcome analyses, the completeness and prespecification of the reported statistical work cannot be evaluated.

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

Serious events with the highest arm-level rate: sarcoidosis (1.5%), depression (1.5%), infarction (1.5%).

For the tocilizumab group, the registry records 68 participants at risk and 3 participants affected by serious adverse events. It records 68 participants at risk and 0 affected by other adverse events. These are participant counts as posted in the registry; they should not be treated as the primary endpoint or as a comparison between treatment groups. No comparator group is described.

The listed serious adverse event terms are Sarcoidosis at 1.5%, Depression at 1.5%, and Infarction at 1.5%. The record does not provide further clinical context for these terms in the posted information. A death count is not reported in the registry record. General interpretation of safety counts depends on the event definitions, observation period, and how events were collected; full details of these methods are not reported in the registry record.

These figures describe the safety information recorded for this study group. They do not establish comparative risk, and the counts alone do not explain causation. They should be read alongside the study’s non-interventional design and the absence of a described control group.

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

The registry record establishes that this completed, multi-center, non-interventional study concerned tocilizumab monotherapy in people with rheumatoid arthritis. It describes routine clinical practice, physician-prescribed regimens, and intended follow-up for 6 months. The primary question concerns the percentage of participants on treatment at Month 6.

The record does not report the numerical primary endpoint result, its 95% confidence interval, or the number of participants in the stated full analysis set. It therefore does not show how many participants continued treatment at Month 6 or how precisely that percentage was estimated. The listed secondary outcomes also have no numerical results in the registry record.

The study can be understood as an observational description of treatment and outcomes in its enrolled group, subject to the information actually posted. Because no randomized comparator is described, the registry does not support a direct comparison with another treatment strategy. More generally, an outcome observed after treatment in a non-interventional study cannot by itself establish that treatment caused the outcome. Participant characteristics and routine-care decisions can shape both treatment exposure and observed outcomes.

The safety information records serious adverse events in 3 participants among 68 at risk, and 0 participants affected by other adverse events among 68 at risk. Those figures describe the registry’s safety counts; they do not resolve the unanswered primary endpoint question or provide a controlled safety comparison.

In short, the record describes the study question and design but does not report the central efficacy estimate. It does not establish a treatment effect, a comparative benefit, or the reasons participants continued or stopped treatment. Those interpretations would require outcome results and methodological details that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study is statistically notable as an example of a routine-practice question framed around a clear treatment-status endpoint. The primary endpoint asks whether participants remained on tocilizumab at Month 6, and the registry defines the population intended for that measure as participants who received at least one dose. That makes the question understandable as a descriptive measure of treatment continuation.

The distinction between a defined endpoint and a reported estimate is important. Although the registry names the endpoint and its 95% confidence interval, neither the numerical percentage nor the interval is reported in the registry record. The number of participants in the defined analysis population is also not reported. Readers therefore cannot determine the continuation estimate or its precision from the posted results.

The non-interventional design also matters statistically. Treatment was given in routine care according to individualized physician prescriptions, and no randomized comparator is described. This can make the study relevant to describing clinical practice, but it does not create the controlled contrast needed to interpret differences as effects caused by treatment. The record does not report adjustment methods that might address differences between participants or treatment decisions.

The registry lists 35 outcome measures but zero analyses. That contrast illustrates why outcome definitions alone are not evidence about observed results. Without posted estimates, analysis details, or information about missing data and multiplicity, the statistical strength and completeness of the intended evaluation cannot be assessed. The study’s statistical importance lies in distinguishing what its design and endpoint can ask from what the registry results actually report.

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 primary limitation for interpreting this trial is that the registry record does not report a numerical result for its primary endpoint. Although the endpoint is defined as the percentage on tocilizumab at Month 6 and a 95% confidence interval is named, neither value is posted. The endpoint population’s size and the number assessed at Month 6 are also not reported.

The registry lists an enrollment of 71, but this is not enough to identify the denominator for the primary analysis. The record does not report how many participants received at least one dose, how many completed the stated follow-up, or how participants without Month 6 status were handled. Reasons for discontinuation and missing outcome data are not reported in the registry record.

The non-interventional design and lack of a described comparator limit causal interpretation. Treatment was prescribed by physicians, and allocation is not stated. The record does not report statistical adjustment for differences among participants or clinical circumstances. It therefore does not support a randomized or like-for-like comparison.

Thirty-five outcome measures are listed, but zero analyses are listed. A statistical analysis plan, multiplicity approach, sample-size justification, and interim-analysis plan are not reported in the registry record. Secondary outcome estimates are also not reported. The safety information includes counts and serious adverse event terms, but a death count is not reported, and the posted details do not describe the event-collection methods. These gaps limit evaluation of both the completeness of the results and their precision.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Non-Interventional Study of Rheumatoid Arthritis Patients Treated With RoActemra/Actemra (Tocilizumab) in Monotherapy — NCT01705730.
• Registry record last updated 2018-09-04; status last verified 2018-08.
• Results first posted 2018-09-04.
• 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

NCT01705730, titled Mon-ACT, is a completed multi-center, non-interventional study of tocilizumab monotherapy in rheumatoid arthritis. Hoffmann-La Roche is listed as the sponsor. The registry records enrollment of 71, a start date of 2012-07-31, and a primary completion date of 2014-12-12. The summary describes intended follow-up for 6 months in routine clinical practice.

The primary endpoint is the percentage of participants on tocilizumab at Month 6 after treatment initiation. Its stated full analysis set includes participants who received at least one dose. The numerical endpoint result, confidence interval, and analysis population size are not reported in the registry record. The record lists 35 outcome measures and zero analyses.

Safety information records 3 participants affected by serious adverse events among 68 at risk and 0 affected by other adverse events among 68 at risk. A death count is not reported in the registry record. No randomized comparator is described, so the posted information is descriptive rather than a controlled treatment comparison.