A Study to Assess the Safety and Efficacy of Risankizumab for Maintenance in Moderate to Severe Plaque Type Psoriasis ( LIMMITLESS ): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Assess the Safety and Efficacy of Risankizumab for Maintenance in Moderate to Severe Plaque Type Psoriasis ( LIMMITLESS ) (NCT03047395), a na phase 3 study. The primary outcome is Number of Participants With Serious Adverse Events and Non-Serious Adverse Events.

2. Clinical Question

3. Trial Design

The registry describes a phase 3, multicenter, open-label study of risankizumab for maintenance in moderate to severe plaque psoriasis. Its official title identifies it as an open-label study. The design is recorded as single-group; allocation is not applicable, and masking is none. These features mean that the posted study is not a randomized, blinded comparison between treatment groups.

The registry lists enrollment as 2170 and status as completed. The recorded study start date is 2017-02-27, and the primary completion date is 2023-11-29. The intervention is risankizumab, a biological product administered by subcutaneous injection. The adverse-event results identify the group as Risankizumab 150 mg.

The primary outcome is the number of participants with serious adverse events and non-serious adverse events. Its timeframe is described as a median follow-up time of 1905 days. A median follow-up duration gives context for the period over which participants were observed, but it does not specify how long each individual was followed or when each event occurred.

Because there is no comparator group, the posted data cannot establish a randomized between-group difference. The registry record does not report a protocol-level statistical analysis plan, eligibility details, or additional design information beyond the design features. It also does not report efficacy results in the outcome information available for this study.

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:

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Serious Adverse Events and Non-Serious Adverse Events, measured over Median follow-up time of 1905 days.

The primary endpoint counts participants with serious adverse events and non-serious adverse events. An adverse event is defined in the registry as an untoward medical occurrence in a patient or clinical investigation subject who has received a pharmaceutical product; the occurrence does not necessarily have a causal relationship with the treatment. The investigator assessed each event’s relationship to study drug as probably related, possibly related, probably not related, or not related.

The registry defines a serious adverse event by its consequences or clinical importance. It includes an event resulting in death, being life-threatening, requiring or prolonging hospitalization, causing a congenital anomaly or persistent or significant disability or incapacity, or constituting an important medical event that may jeopardize the subject and may require medical or surgical intervention to prevent such outcomes.

Safety outcomes of this kind are used to describe events observed during treatment and follow-up. They do not, by themselves, establish that treatment caused an event. A participant count also differs from a count of all event episodes: the endpoint is expressed in participants, so it concerns how many participants experienced events rather than how many separate events occurred. The registry does not report a separate efficacy endpoint in the posted outcome information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count mean? The endpoint is expressed as participants with events. Such a count indicates how many people were recorded as experiencing an event in the specified category; it is not the same as the total number of event episodes. A participant can experience more than one event, but the registry’s primary outcome is a participant count. The record does not give the total number of event episodes for this outcome.

Why does the denominator matter? The record lists 2170 participants at risk for each of the serious and other adverse-event categories, alongside the corresponding affected-participant counts. These denominators help identify the group to which the counts refer. They do not create a comparison group: the study has a single group and no randomized control arm. The registry does not report adjusted comparisons or a treatment-effect estimate for this outcome.

What can follow-up tell us? The stated median follow-up time is 1905 days. General explanation: follow-up duration matters because participants may be observed for different lengths of time, and longer observation can create more opportunity to record an event. A median provides a summary of follow-up, not each participant’s observation time. Without participant-level times or person-time, the counts cannot be converted into time-adjusted event rates. Those additional data are not reported in the registry record.

What is the distinction between an event and a treatment-related event? General explanation: an adverse event is defined by its occurrence after a participant receives a product, not by proof that the product caused it. The investigator’s relationship assessment is a separate judgment. The registry lists the possible assessment categories, but the posted results do not provide counts by those categories. The overall adverse-event counts therefore should not be described as counts of events caused by treatment.

How should serious-event terms be understood? The record lists six frequent serious-event terms with percentages: OSTEOARTHRITIS, 0.8%; ACUTE MYOCARDIAL INFARCTION, 0.6%; COVID-19, 0.6%; ATRIAL FIBRILLATION, 0.4%; CORONARY ARTERY DISEASE, 0.4%; and MYOCARDIAL INFARCTION, 0.4%. These are descriptive terms, not comparative treatment effects. The registry does not report the denominator definition or detail whether participants could contribute to more than one term. General explanation: event categories may overlap, so percentages for different terms should not automatically be summed.

What does a confidence interval normally add? General explanation: a confidence interval expresses the statistical uncertainty around an estimate under a specified method. It can help readers distinguish a relatively precise estimate from one with substantial uncertainty. The posted outcome information does not include an estimate with a confidence interval, so precision cannot be assessed that way for the participant counts. The registry record also does not report an inferential analysis for this endpoint.

What is over-dispersion, and does it apply? General explanation: over-dispersion is a feature of some count data in which variability exceeds what a chosen statistical model expects. It can affect standard errors and inference when analyses model event counts. This outcome is reported as participants with events, and no count-model analysis is reported in the registry record. There is therefore no posted model from which to assess over-dispersion.

How should planning calculations be read? General explanation: sample-size calculations are planning tools, not observed results. The registry describes an illustrative calculation using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of an observed effect. It states that this illustration is not the trial’s own design. Those assumptions do not turn this single-group study into a two-arm comparison, and a planning illustration is not observed power. Numerical planning results are not reported in the registry record.

What does the absence of an analysis mean? The registry lists one outcome measure and no analyses. This means no inferential analysis is posted in the posted outcome information. It does not establish what analyses may have been conducted outside the registry record. The statistical analysis plan, any model specifications, handling of repeated events, and any adjusted estimates are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure and no analyses. A multiplicity strategy for testing several endpoints or contrasts is not reported in the registry record. Because no inferential results are posted, there are no reported p-values or confidence intervals for which an adjustment can be evaluated. It would be inappropriate to infer an analysis plan from the outcome count alone.

Missing-data procedures are not reported in the registry record. The record does not describe how participants with incomplete follow-up, missing event assessments, or withdrawal were handled in the posted counts. It also does not report a sensitivity analysis for missing data. General explanation: missingness can matter when the chance that an outcome is unobserved is related to a participant’s health or experience; the direction and size of any resulting bias depend on the circumstances and cannot be determined without further information.

The analysis populations are not reported in the registry record. Although the adverse-event results list 2170 participants at risk in each category, the record does not specify whether these participants constitute a safety population, an intention-to-treat population, or another analysis set. The statistical analysis plan and any rules for inclusion in the endpoint analysis are not reported in the registry record.

The study is single-group and open-label, with no masking. The registry does not report a multiplicity approach, missing-data approach, or analysis population that would support a more detailed reconstruction of the statistical methods. These omissions limit what can be concluded about the analysis beyond the descriptive counts.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: osteoarthritis (0.8%), acute myocardial infarction (0.6%), covid-19 (0.6%), atrial fibrillation (0.4%), coronary artery disease (0.4%).

The serious adverse-event results list 2170 participants at risk and 435 affected in the Risankizumab 150 mg group. The other adverse-event results list 2170 at risk and 1215 affected. These are participant counts in a single treatment group, with a median follow-up time of 1905 days. They are not event rates adjusted for exposure time and do not provide a comparison against another group.

The record lists 28 deaths. Since death meets the registry definition of a serious adverse event, the death count may overlap with the serious-event count; the record does not report the overlap. The listed serious-event terms and percentages are OSTEOARTHRITIS, 0.8%; ACUTE MYOCARDIAL INFARCTION, 0.6%; COVID-19, 0.6%; ATRIAL FIBRILLATION, 0.4%; CORONARY ARTERY DISEASE, 0.4%; and MYOCARDIAL INFARCTION, 0.4%. The registry does not provide a basis for summing these terms or interpreting them as caused by study drug.

General explanation: safety counts document events observed during a study; they do not establish causation. The registry’s investigator relationship categories are described, but counts by relationship category are not reported in the registry record.

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

The results describe adverse events recorded among participants in a single-group, open-label study of risankizumab. The posted counts include 435 participants with serious adverse events and 1215 with other adverse events, among 2170 participants listed at risk in each category. The record also reports 28 deaths and a median follow-up time of 1905 days. These figures provide a descriptive account of the safety outcome as posted.

They do not show how the event counts compare with what would have occurred under another treatment or no study treatment. There is no randomized comparator group, and allocation is listed as not applicable. The counts therefore cannot establish a relative treatment effect. They also do not show, on their own, whether a particular event was caused by risankizumab. The registry defines an investigator assessment process, but its results by relationship category are not reported.

The counts do not provide event timing or rates adjusted for time at risk. The median follow-up duration supplies context, but the registry does not report individual follow-up times or person-time. The posted information also does not include inferential estimates, confidence intervals, or efficacy results.

General explanation: a descriptive result and a causal conclusion answer different questions. A descriptive result records what happened in the observed group. A causal estimate requires a suitable comparison and methods that address differences between the groups being compared. In a single-group study, the registry results can describe observed events but cannot provide a randomized comparison. The record does not report the additional analyses or design information that might address other comparisons.

Accordingly, the posted outcome should be read as a safety description from the study group, not as proof of benefit, proof of harm, or a comparative estimate. The registry record does not report efficacy findings, detailed analysis methods, or event attribution results that would support broader conclusions.

13. Why This Trial Matters Statistically

This study is statistically informative as a large, long-followed, single-group safety record. The registry lists enrollment of 2170 and a median follow-up time of 1905 days. Such descriptive follow-up can document the types of adverse events observed in the study population and the number of participants recorded in each posted category.

Its design also illustrates an important distinction between describing events and estimating comparative effects. The study is open-label and single-group, with no randomized comparator. The safety counts therefore characterize the treated group but do not show whether the observed counts differ from those under another treatment. This limitation remains even when participant counts are substantial: sample size alone does not supply a counterfactual comparison.

The registry’s event definition also highlights the distinction between occurrence and causation. An adverse event need not be caused by treatment, and the record describes investigator assessments of relatedness. However, the posted results do not include counts by those assessments. That makes it important to keep the overall event counts separate from claims about drug-related events.

Finally, the record shows why statistical interpretation depends on more than a headline count. Follow-up duration, analysis populations, missing-data procedures, event timing, and uncertainty estimates affect how fully readers can interpret safety outcomes. Several of these details are not reported in the registry record. The posted information supports a description of the recorded events, while leaving comparative and inferential questions unanswered.

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 principal limitation is the single-group, open-label design. Allocation is listed as not applicable, masking as none, and no comparator group is described. Consequently, the posted counts do not provide a randomized comparison with another treatment or control condition. The record does not report a comparative efficacy estimate.

The primary outcome is a participant count, while the record does not report event timing, individual follow-up duration, or person-time. The median follow-up time of 1905 days gives a summary but does not permit time-adjusted interpretation of the counts. The relationship between the 28 deaths and the serious-adverse-event count is not reported in the registry record.

Although the registry describes investigator categories for assessing relationship to study drug, results by those categories are not reported. The record also does not report the denominator details for the percentages attached to the frequent serious-event terms, whether event terms overlap, or the analysis population used for the outcome.

Missing-data methods, sensitivity analyses, and a statistical analysis plan are not reported in the registry record. No inferential analysis is posted. Efficacy findings are not reported in the outcome information. These limits mean the available information supports descriptive interpretation of the reported safety counts but does not resolve causality, comparative effects, or the precision of an estimated treatment effect.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Study to Assess the Safety and Efficacy of Risankizumab for Maintenance in Moderate to Severe Plaque Type Psoriasis ( LIMMITLESS ) — NCT03047395.
• Registry record last updated 2024-12-11; status last verified 2024-11.
• Results first posted 2024-12-11.
• 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

The registry record identifies NCT03047395 as a completed phase 3, multicenter, open-label, single-group study of risankizumab for maintenance in moderate to severe plaque psoriasis. Enrollment was 2170. The recorded study start date is 2017-02-27, and the primary completion date is 2023-11-29. The intervention is described as subcutaneous risankizumab, and the adverse-event group is titled Risankizumab 150 mg.

The primary outcome counts participants with serious and non-serious adverse events over a median follow-up time of 1905 days. The record lists 435 participants with serious adverse events, 1215 with other adverse events, and 28 deaths. It lists frequent serious-event terms with percentages, but does not report efficacy results, a comparator, inferential analyses, or detailed missing-data and analysis-population methods. The posted results are descriptive and do not establish comparative treatment effects or event causation.