Safety and Tolerability of AIN457 in Adults (18-65 Years) With Psoriatic Arthritis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Tolerability of AIN457 in Adults (18-65 Years) With Psoriatic Arthritis (NCT01169844), a non-randomized phase 2 study. The primary outcome is Number of Participants With Adverse Events and Serious Adverse Events.

2. Clinical Question

The central question is about safety and tolerability during continued treatment, rather than a randomized estimate of treatment efficacy. The registry describes the study as an extension intended to continue AIN457 treatment for participants from the core trial and to collect safety and tolerability information. It also says efficacy would be evaluated, but the primary outcome listed in the record counts participants with adverse events and serious adverse events.

The two extension groups reflect different treatment histories in the core study: one group had received AIN457 and the other placebo. During the extension, both groups are described as receiving AIN457 at 3 mg/kg. This means the earlier core-trial assignment does not create a concurrent untreated or placebo group in the extension. The registry explicitly cautions that the arms are not a like-for-like control comparison.

The posted information therefore supports a descriptive question: what adverse-event counts were recorded in each group? It does not support a causal comparison of the groups’ outcomes or a conclusion about efficacy. The primary endpoint timeframe is listed as up to 64 weeks, while the treatment descriptions refer to a total period of 52 weeks. The registry record does not explain the relationship between those timeframes.

3. Trial Design

This was a Phase 2, open-label, non-randomized, single-group extension study. The registry lists an enrollment of 28 and describes the population as patients with psoriatic arthritis who participated in core trial CAIN457A2206. The study is marked completed. The listed study start is 2010-06 and the primary completion is 2012-11.

The extension included two groups defined by treatment received during the core study. Participants previously treated with secukinumab 2x10 mg/kg are described as receiving secukinumab at 3 mg/kg during the extension. Participants previously treated with placebo are also described as receiving secukinumab at 3 mg/kg. In both descriptions, the extension treatment was given by intravenous infusion every 4 weeks over a total period of 52 weeks.

The brief study description gives a staged account of planned treatment: dosing was initially intended to continue for up to 6 months, followed by a decision about another 6 month period based on the risk/benefit balance. The arm descriptions instead state a total treatment period of 52 weeks, and the primary endpoint timeframe is up to 64 weeks. The registry record does not explain how these descriptions relate to one another, so they should be treated as distinct statements in the record rather than reconciled by assumption.

There was no masking, and allocation is listed as non-randomized. The two groups are consequently not randomized extension arms with exchangeable treatment assignment. Their prior core-study treatment histories differ, and both groups received AIN457 during the extension. Any difference in their observed event counts could reflect factors beyond extension treatment, including differences in the groups before the extension began.

The study is described as focused on safety and tolerability, with secondary outcomes concerning total IL-17 concentration in blood at steady state and mean serum concentration measured at steady state. Numerical results for those secondary outcomes are not reported in the registry record.

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 42 patients were randomized in the (CAIN457A2206) core study, of which 28 patients enrolled into the (CAIN457A2206E1) extension study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The safety population consisted of all randomized patients who received at least one dose of the study drug.

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 Adverse Events and Serious Adverse Events, measured over Up to 64 weeks (End of the Study Treatment).

The primary endpoint is the number of participants with adverse events and serious adverse events, reported as counts of participants. An adverse event was defined as an unfavorable and unintended diagnosis, symptom, sign, syndrome, or disease that arose during the study or worsened if already present at baseline. The definition includes abnormal laboratory findings.

A serious adverse event was defined by consequences or clinical significance: death, a life-threatening event, a need for or extension of hospitalization, persistent or significant disability or incapacity, congenital anomalies or birth defects, or another condition judged by investigators to represent a significant hazard. These definitions distinguish seriousness from whether an event is expected or caused by treatment; the endpoint description does not say that every counted event was considered treatment-related.

Counting participants with one or more events is useful in a safety study because it conveys how many people experienced an event, rather than only listing event episodes. It is a participant-level measure: multiple events in one person do not necessarily correspond to multiple participants in the count. The primary endpoint timeframe is listed as up to 64 weeks, at the end of study treatment.

The registry defines the safety population as all randomized patients who received at least one dose of study drug. Because the extension itself is listed as non-randomized, that wording is not fully aligned with the recorded design. The record does not clarify how the safety population was operationalized for this extension.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The information in the registry supports a descriptive reading of the safety outcomes, not a reconstruction of a full statistical analysis plan. The study is listed as non-randomized, unmasked, and single-group, and no analysis results are listed. The record does not report a specific model, hypothesis test, adjustment strategy, or confidence interval for the primary endpoint.

What does a participant count represent?

The primary measure counts participants with adverse events and serious adverse events. A participant count is different from an event count. One participant may experience more than one event, but the participant contributes only once to a count of people with at least one event of the relevant type. The posted primary results therefore describe how many participants were affected, not the total number of event episodes or the number of events per participant.

That distinction is important when comparing safety summaries. Event counts can be influenced by recurrent events in a small number of people, whereas participant counts focus on whether participants experienced an event. The registry names the endpoint as a count of participants, so interpreting it as a count of all individual events would not match the stated measure.

Why does the design affect interpretation?

Randomization is a general method for making treatment groups comparable on average, including on factors that may not have been measured. This extension is explicitly non-randomized, and participants entered the extension with different core-trial treatment histories. Both groups then received AIN457. Consequently, differences in the posted counts cannot be isolated as effects of different extension treatments. The registry itself cautions that the arms are not a like-for-like control comparison.

Open-label means the study is listed as having no masking. This is relevant context for interpreting reporting and assessment of events, especially where investigator judgment is part of the serious-event definition. The registry does not describe procedures for independent event review or blinded adjudication, so none should be assumed.

What can the percentages for event terms tell a reader?

The record lists percentages beside selected serious adverse-event terms. These percentages are descriptive entries, not a complete comparative analysis. A percentage alone does not show whether a term occurred once or repeatedly, whether a participant had more than one listed term, or how the terms were selected for listing. No additional method for selecting or grouping these terms is reported in the registry record.

In general, safety interpretation should distinguish a percentage describing observed participants from a causal estimate comparing treatment strategies. The extension’s design does not provide a randomized contrast for that purpose. The listed percentages should therefore be read as registry descriptions of reported terms, not as evidence of differences attributable to treatment.

What is a confidence interval, and is one reported?

In general, a confidence interval describes the uncertainty around an estimated quantity under a specified statistical procedure. It can help readers assess how precisely an estimate is supported by the data. The registry record does not report confidence intervals for these primary safety counts. Counts alone do not communicate the full uncertainty around an underlying event frequency, particularly when group sizes are limited.

A confidence interval would not remove design limitations: an estimate can be precise for a non-randomized group and still not establish a causal treatment effect. Statistical precision and comparability of groups are separate issues.

Why does the record’s analysis information matter?

The registry lists zero analyses. This means no analysis results are recorded in the information available for this trial, not that a particular statistical method was used or that an analysis was never conducted elsewhere. The record does not state how missing observations were handled, whether the primary outcome was analyzed at a planned interim point, or whether any covariates were included in an analysis.

The sample-size assumptions describe planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such illustrations are not the trial’s own design justification and are not observed power. In general, planning calculations depend on assumptions about the effect to detect and the analysis method; they do not replace the observed outcome results or repair limitations in a non-randomized design. A trial-specific sample-size justification is not reported in the registry record.

Over-dispersion is a general issue for some count outcomes: it occurs when variation in counts exceeds what a chosen statistical model expects. It can affect uncertainty estimates if a model assumes less variability than the data contain. It is not possible to say whether over-dispersion was assessed or relevant to an analysis of this endpoint, because the record lists participant counts and does not report a count model or model diagnostics.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint is identified as the number of participants with adverse events and serious adverse events. The registry also lists secondary outcomes for total IL-17 concentration in blood at steady state and mean serum concentration measured at steady state. It lists 3 outcome measures overall, but numerical results for the secondary measures are not reported in the registry record.

Multiplicity refers, in general, to the statistical issue that arises when several outcomes, timepoints, groups, or analyses are tested. Considering many tests can increase the chance of finding an apparently unusual result by chance. A prespecified testing hierarchy or adjustment can address some multiplicity concerns. No multiplicity strategy or hierarchy is reported in the registry record, and no analysis results are listed. It is therefore not possible to determine whether multiplicity was considered or how it might affect any inferential claims.

The record does not report how missing outcome data were handled, the number of participants with missing endpoint information, or whether all participants were followed for the same duration. It also does not describe imputation, censoring, or sensitivity analyses for missing data. Those details matter because incomplete follow-up can affect the interpretation of event counts, especially when the endpoint period is stated as up to 64 weeks.

The safety population is defined in the record as all randomized patients who received at least one dose. The extension’s allocation is separately described as non-randomized. The record does not clarify how the population definition was applied, whether it refers to the core study, or how participants were included in each outcome analysis. The number of analyses is listed as zero, so no analysis population or analysis-specific handling can be verified from posted results.

The registry does not report interim analyses, a formal statistical analysis plan, or a protocol-based sample-size justification. Those elements should not be inferred from the planning illustrations, which are described as illustrations rather than the trial’s own design.

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: myocardial infarction (11.1%), sciatica (11.1%), osteoarthritis (10.5%), viral sinusitis (5.3%), diabetes mellitus inadequate control (5.3%).

The serious adverse-event counts are 5 of 19 participants in the AIN457/AIN457 3 mg/kg group and 2 of 9 participants in the Placebo/AIN457 3 mg/kg group. These are participant counts, not counts of every serious-event episode. The registry also records 0 deaths in each group.

The broader adverse-event counts are 19 of 19 and 9 of 9, respectively. The endpoint definitions explain why the broader count can include events that do not meet the serious-event criteria. These counts are descriptive of the participants recorded in each group and should not be treated as a controlled comparison.

Selected serious adverse-event terms are accompanied by the percentages listed in the registry: Myocardial infarction and Sciatica, 11.1% each; Osteoarthritis, 10.5%; Viral sinusitis, Diabetes mellitus inadequate control, and Arthralgia, 5.3% each. The record does not give enough context to interpret these term-level percentages as comparative risks or to determine how event recurrence and overlap between terms were handled.

The study was non-randomized, and both groups received AIN457 during the extension after different core-study treatment histories. The counts therefore do not establish that treatment caused or prevented any listed event.

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

The posted data describe adverse events observed during an open-label extension involving participants with psoriatic arthritis. They show that serious adverse events were recorded in both extension groups, that other adverse events were recorded for every participant in each group, and that no deaths were recorded in either group. These statements are limited to the registry’s listed counts and definitions.

The results do not establish that AIN457 caused any particular event. An adverse event is defined as an unfavorable medical occurrence during the study, including one that worsens from baseline; the definition does not itself imply causation. The serious-event definition similarly classifies events by outcome or investigator judgment, rather than by proof that the study drug caused them.

The results also do not show whether AIN457 was more or less effective than placebo or another treatment. Although participants in one group had received placebo in the core study, both groups are described as receiving AIN457 during the extension. There was no randomized extension control, and the registry warns that the arms are not like-for-like. Differences in counts cannot be attributed to treatment history or extension treatment on the basis of these data.

The listed event-term percentages are not substitutes for comparative estimates. The registry does not report confidence intervals, adjusted analyses, or tests of differences for these outcomes. Counts and percentages convey what was recorded, but do not by themselves establish the precision of an underlying frequency or its generalizability beyond the study participants.

The study’s extension purpose is relevant: it sought continued treatment and safety and tolerability information after a core trial. That makes descriptive safety follow-up meaningful, while also distinguishing it from a randomized efficacy trial. The record does not report numerical results for the listed secondary concentration outcomes, so no conclusion about those measures can be drawn from the posted information.

Overall, the findings are a record of observed events in the stated groups and timeframe. They should not be read as proof of safety in all patients, as a causal comparison, or as evidence of efficacy. The registry record does not report enough detail to resolve the different endpoint and treatment-duration descriptions or to assess missing data and analysis procedures.

13. Why This Trial Matters Statistically

This trial illustrates a common statistical distinction: a study can provide useful descriptive safety information without providing a valid randomized comparison of treatments. In an extension, participants may continue into follow-up after a core trial, and their earlier treatment histories can shape the groups that are observed. Here, both extension groups are described as receiving AIN457, while the registry explicitly states that the arms are not a like-for-like control comparison.

The distinction between participants and events is also important. A participant-level count answers how many people experienced at least one event of a category. It does not reveal the total number of event episodes or the burden of recurrent events. Clear identification of the unit is essential when reading clinical safety results.

The record also demonstrates why outcome definitions matter. The primary outcome distinguishes adverse events from serious adverse events using criteria based on consequences and investigator judgment. Those categories answer related but different questions, and neither category by itself identifies whether an event was caused by treatment.

Finally, interpretation depends on what the registry does not document. No analysis results, confidence intervals, missing-data methods, or multiplicity strategy are listed. Such omissions do not negate the reported counts, but they limit the statistical claims readers can make. A disciplined reading separates the observed counts from conclusions about causation, treatment differences, and precision.

For biostatisticians and clinical researchers, this extension is a reminder to align design, endpoint, analysis population, and claims. The non-randomized structure supports a descriptive account of events among participants followed in the extension; it does not create the exchangeability needed for a strong causal comparison. The record’s explicit design caveat is central to understanding what these safety data can and cannot establish.

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 most important limitation is the non-randomized extension design. Participants entered with different core-trial treatment histories, and both groups received AIN457 during the extension. The registry cautions that the groups are not a like-for-like control comparison. Counts between groups should therefore not be interpreted as a causal contrast.

The study was open-label, with masking listed as none. The record does not describe independent or blinded review of adverse events. Since the serious-event definition includes investigator judgment, the absence of information about event adjudication is relevant to interpretation.

The endpoint timeframe is listed as up to 64 weeks, while the arm descriptions state a total treatment period of 52 weeks. The brief summary describes an initial period up to 6 months and a possible additional 6 month period. The registry record does not reconcile these descriptions. It also does not report how long each participant was followed or how participants with shorter follow-up contributed to the counts.

The safety population wording refers to randomized patients who received at least one dose, although the extension is listed as non-randomized. The record does not clarify the application of that definition. Missing-data handling, outcome-specific denominators beyond the listed group counts, and sensitivity analyses are not reported.

No analysis results are listed. The record therefore does not provide inferential estimates, confidence intervals, adjusted comparisons, or a statistical analysis plan. It does not report a trial-specific sample-size justification or interim analyses. Numerical results for the secondary concentration outcomes are also not reported in the registry record. These limitations restrict the interpretation to the posted descriptive safety counts and terms.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety and Tolerability of AIN457 in Adults (18-65 Years) With Psoriatic Arthritis — NCT01169844.
• Registry record last updated 2021-06-10; status last verified 2021-05.
• Results first posted 2021-05-27.
• 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

NCT01169844 is a completed Phase 2, open-label, non-randomized extension study of AIN457 in adults with psoriatic arthritis. The registry lists an enrollment of 28 and describes continued treatment after core trial CAIN457A2206. Both extension groups are described as receiving AIN457 at 3 mg/kg by intravenous infusion every 4 weeks.

The primary endpoint counts participants with adverse events and serious adverse events. The registry lists serious adverse events for 5 of 19 participants in the AIN457/AIN457 group and 2 of 9 in the Placebo/AIN457 group, with 0 deaths in each group. It records other adverse events for 19 of 19 and 9 of 9 participants, respectively. The groups are not a randomized, like-for-like comparison.

No analysis results are listed. Missing-data methods, multiplicity handling, and a trial-specific sample-size justification are not reported in the registry record. The primary endpoint timeframe and treatment-duration descriptions are not fully aligned in the record.