Study to Assess the Long-term Safety, Tolerability, and Efficacy of AMG 827 in Subjects With Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Assess the Long-term Safety, Tolerability, and Efficacy of AMG 827 in Subjects With Psoriasis (NCT01101100), a na phase 2 study. The primary outcome is Percentage of Participants With a Static Physician's Global Assessment (sPGA) of Clear (0) or Clear/Almost Clear (0 or 1).

2. Clinical Question

3. Trial Design

The registry describes a Phase 2, single-group, open-label extension study of AMG 827 in subjects with psoriasis. Its brief summary identifies it as an extension of study 20090062 intended to evaluate extended subcutaneous dosing. The intervention is AMG 827, administered subcutaneously. The record lists enrollment of 181 and marks the study as terminated.

Allocation is recorded as not applicable, and masking is none. These features fit the single-group design: the record does not list a parallel control arm or a blinded comparison. Consequently, the study description is about follow-up during AMG 827 treatment, not a randomized estimate of how outcomes differ between treatment groups. Changes over time, if reported elsewhere, would still need to be interpreted in light of the absence of a concurrent control in this record.

The study start is recorded as 2010-04, and primary completion as 2015-09. The primary endpoint timeframe is 264 weeks. The record says results cover data up to week 264 because all continuing subjects had completed that visit. This wording does not establish that every enrolled subject had a valid measurement at that time; the endpoint population is described as enrolled subjects with a valid measurement at the specified week.

The registry status is terminated. A reason for termination, the timing of termination relative to individual participants’ follow-up, and any effect on the planned conduct are not reported in the registry record. Further details on the dosing schedule, visit schedule, eligibility criteria, treatment discontinuation, and any protocol amendments are also not reported in the registry record. These absences limit how fully the treatment exposure and follow-up can be reconstructed from the posted 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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Subjects who were enrolled and had a valid measurement value at the specified week. Results are presented for data up to week 264 as all continuing subjects had completed that visit.

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 Percentage of Participants With a Static Physician's Global Assessment (sPGA) of Clear (0) or Clear/Almost Clear (0 or 1), measured over 264 weeks.

The primary endpoint is the percentage of participants with a static Physician’s Global Assessment (sPGA) score of clear (0) or clear/almost clear (0 or 1) at 264 weeks. The sPGA is a clinician assessment of psoriasis severity. For this endpoint, participants are grouped according to whether their assessment meets the stated clear or almost-clear category threshold at the specified visit.

A percentage expresses the share of the endpoint population meeting that threshold, rather than the number of lesions or a change in severity for each participant. It can be useful because it gives a clinically interpretable count-based outcome: whether a participant is in one of the specified assessment categories at that time. It does not, by itself, describe how far participants outside those categories are from the threshold, or how their scores changed from an earlier visit.

The endpoint population is described as subjects who were enrolled and had a valid measurement value at the specified week. The record says reporting extends through week 264 because all continuing subjects had completed that visit. It does not report the number with valid measurements or the endpoint percentage, so the observed frequency and its precision cannot be assessed from the stated endpoint information. Nor does this single-group endpoint establish what would have occurred under a different treatment or without treatment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods describe how outcomes are converted into estimates and how uncertainty is assessed. In this record, the design and endpoint are described, but no analysis results are recorded. The distinction between a stated endpoint and a reported estimate is important: knowing what was measured does not reveal the observed result or its precision.

What does a single-group outcome estimate represent?

For a binary endpoint such as meeting a defined assessment threshold, the basic descriptive quantity is the proportion of participants meeting the criterion among those included in the analysis. A count is the number meeting the criterion, and a denominator is the number evaluated. The registry describes the week 264 outcome as a percentage among enrolled subjects with a valid measurement at the specified week, but the numerical percentage, count, and denominator are not reported in the registry record.

In a single-group study, this proportion is descriptive of the observed study population and measurement time. It is not a difference between treatment groups. A contrast intended to estimate the relative or absolute effect of treatment requires a relevant comparator and a clearly specified comparison. Here the record identifies no concurrent control group, and allocation is recorded as not applicable. Comparisons with results from other studies would require careful consideration of differences in populations, follow-up, definitions, and methods; such comparisons are not reported in this record.

What does uncertainty mean?

General statistical explanation: an estimate from a sample is subject to uncertainty because the observed participants are not necessarily identical to the wider population of interest. A confidence interval is one way to express the range of values compatible with the data under a specified statistical model. Its width reflects both the amount of information and the variability in the observations. A narrow interval generally indicates greater precision than a wide interval, but neither an interval nor a point estimate alone resolves design limitations such as the absence of a control group.

No confidence interval or other uncertainty estimate for the primary endpoint is reported in the registry record. Without the endpoint count and denominator, the uncertainty of the observed percentage cannot be assessed. A p-value, if available, would answer a question framed by a statistical test; it would not replace the endpoint estimate, quantify the importance of an outcome, or address bias caused by missing measurements or lack of a comparator. No p-value or test result is reported in the registry record.

Why does the analysis population matter?

The endpoint description limits the analysis population to subjects enrolled and having a valid measurement at the specified week. This is a measurement-based population definition. It differs from treating all enrolled participants as if a week 264 measurement were available. If participants without valid measurements differ from those with measurements, an estimate limited to observed values may be subject to selection bias. This is a general methodological concern; the registry record does not report whether, or how much, such differences occurred.

Missing-data methods can make different assumptions about outcomes that were not observed. For example, an analysis may exclude missing measurements, use a specified imputation method, or model repeated observations. Each approach has assumptions, and sensitivity analyses can examine whether conclusions change under alternative assumptions. The method used for the primary outcome, reasons for missing measurements, and any sensitivity analyses are not reported in the registry record. No method should be presumed from the endpoint wording alone.

How should the planning illustrations be understood?

General statistical explanation: sample-size calculations estimate how much information a future study may need to detect a defined effect under chosen assumptions. They are planning tools, not evidence that an effect was observed, and they do not establish the probability that a finding is true. The record’s planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as fractions of an observed effect. For time-to-event calculations, the stated convention is a total event count; for other calculations, it is participants per arm.

Those assumptions describe hypothetical planning for a two-arm comparison. This trial is recorded as single-group, with no control comparison. Any such planning illustration should therefore not be read as a design feature of this extension, as an observed-power calculation, or as evidence that the trial was powered for the week 264 endpoint. The registry does not report a sample-size justification or the trial’s own statistical analysis plan. The observed endpoint effect needed to evaluate a planning illustration is not reported in the registry record.

Why can event counts differ from participant counts?

General statistical explanation: a participant can experience more than one adverse event, and event reporting can count events, participants with at least one event, or both. These quantities answer different questions. A count of participants affected should not be interpreted as the total number of event episodes unless the record explicitly defines it that way. The safety figures in this record are presented as participants affected and participants at risk for the listed categories; event-level totals and further counting rules are not reported in the registry record.

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("Open Label AMG 827")
n      <- c(107)
events <- c(66)
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  Open Label AMG 827  107  66  61.7  51.8  70.9  52.2  70.3  52.2  70.3

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and identifies the sPGA threshold at 264 weeks as the primary endpoint. It does not report an analysis for either outcome. The registry record does not describe a multiplicity-control strategy, a hierarchy of hypotheses, or whether any outcome analyses were planned as confirmatory or exploratory. Without those details, the record does not establish how the chance of false-positive findings across multiple outcomes or analyses would have been addressed.

The primary endpoint population is described as enrolled subjects with a valid measurement at the specified week. The number with a valid week 264 measurement, the reasons measurements were unavailable, and the handling of missing data are not reported in the registry record. It is therefore not possible to determine from the record how much follow-up contributed to the endpoint or whether missingness was related to participants’ health, treatment experience, or other factors.

The record also does not report an analysis population beyond the endpoint description, such as a population based on treatment received or a specified follow-up rule. Methods for participants who discontinued treatment, withdrew, or had incomplete follow-up are not described. No sensitivity analysis addressing alternative assumptions about missing outcomes is reported in the registry record.

These omissions matter because endpoint definitions and missing-data assumptions can affect both the estimate and its interpretation. The stated endpoint identifies what was to be measured, but does not supply the analysis details needed to assess completeness, robustness, or multiplicity. Since no analysis results are recorded, there are no reported hypothesis tests or estimates to evaluate for these issues.

12. 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 infaraction (1.7%), pustular psoriasis (1.7%), osteoarthritis (1.1%), depression (1.1%), angina pectoris (0.6%).

The registry reports safety information for the open-label AMG 827 group. It lists 181 participants at risk for serious adverse events and 29 participants affected. For other adverse events, it lists 181 at risk and 177 affected. The record also reports one death. These figures describe participants in the study group; they do not provide a comparison with a control group.

The most frequently listed serious adverse event terms include Myocardial Infaraction and Pustular Psoriasis, each reported as 1.7%; Osteoarthritis and Depression, each at 1.1%; and Angina Pectoris and Hepatitis C, each at 0.6%. These percentages are reproduced as reported. The registry does not provide event counts beside these term percentages in the stated information, nor does it report a causal assessment for each term.

Serious adverse events are not synonymous with all adverse events, and participant counts are not necessarily event-episode counts. A participant may have more than one event; the figures should not be added or treated as mutually exclusive categories. The record does not give the timing, duration, outcome, or treatment relationship for each event. In this uncontrolled extension, the counts describe reported safety experience but cannot by themselves determine which events were caused by AMG 827.

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

The record establishes that this was a Phase 2, open-label, single-group extension of AMG 827 treatment in subjects with psoriasis. It defines a long-term primary outcome: the percentage meeting an sPGA category of clear or clear/almost clear at 264 weeks. It also reports safety counts for participants in the treatment group. These details help identify what was studied and what the registry recorded.

The record does not include a numerical result for the primary endpoint. It therefore does not show what percentage of participants met the stated threshold, how many had valid measurements, or how precise an estimate would be. No inferential analysis results are recorded. Without these, the primary outcome cannot be quantitatively interpreted from the record.

Even if a single-group outcome proportion were available, it would describe observed participants at a particular time rather than establish a causal treatment effect. The absence of a concurrent control means that differences attributable to treatment cannot be separated from other possible explanations using this study design alone. Open-label assessment may also be subject to knowledge of treatment, although the extent of any such influence is not reported in the registry record.

The safety figures are descriptive and should be read in the context of the reported group and follow-up. The counts do not establish that AMG 827 caused an event, and there is no control group in this record to contextualize comparative safety. The percentages attached to specific serious-event terms are registry-reported values, not estimates of treatment-attributable excess risk.

The status is terminated, but the reason and its implications for follow-up are not reported in the registry record. The stated endpoint timeframe and completion of the visit by continuing subjects do not establish that all enrolled participants had complete measurements. Overall, the record supports a description of study design, measurement, and reported safety experience, but does not provide the outcome analysis needed to make a numerical efficacy assessment or a controlled benefit-risk comparison.

14. Why This Trial Matters Statistically

This study raises statistical issues that are especially important in long-term extension research. The endpoint is measured at 264 weeks, while the primary population is limited to people with a valid measurement at the specified visit. Long follow-up makes it important to know how many participants remain under observation, how many have measurements, and why follow-up is incomplete. Those details are not reported in the registry record.

The single-group design also shapes what can be learned. A proportion meeting a threshold during treatment can describe the observed group, but a treatment contrast requires an appropriate comparator. Without one, changes over time cannot be confidently assigned to treatment rather than to other influences. This is a design limitation, not a statistical adjustment that can be resolved merely by applying a more elaborate model to the same uncontrolled data.

Long-term safety reporting likewise calls for careful separation of people affected from event episodes and of observed events from events caused by treatment. The registry reports participant counts for serious and other adverse events, along with selected serious-event term percentages and a death. The information does not give comparative rates or individual-level timing and attribution. Such counts can characterize what was reported, but their interpretation depends on follow-up and event definitions.

Finally, a clearly stated endpoint is not a substitute for a posted analysis. The absence of numerical outcome results, uncertainty estimates, analysis populations, and missing-data methods prevents readers from judging precision and robustness. The record is therefore useful for identifying the long-term question and the design context, while also demonstrating why transparent endpoint results and analysis details are essential for interpreting an extension study.

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 primary outcome is that no numerical result is reported in the registry record. The endpoint definition is available, but its percentage, numerator, denominator, and uncertainty are not. The record also does not report the number of participants with valid week 264 measurements, so the completeness of endpoint follow-up cannot be evaluated.

The study is open-label and single-group, with no concurrent control group identified. As a result, the record does not support a controlled estimate of treatment effect. It also cannot separate treatment-related changes from other time-related or participant-related influences. The amount of any assessment-related bias is not reported in the registry record.

The registry status is terminated, but the reason for termination is not reported. The stated week 264 reporting window applies because all continuing subjects had completed that visit; it does not establish that every enrolled subject continued or had a valid measurement. Participant flow, treatment discontinuation, and follow-up after discontinuation are not described in the stated information.

Methods needed to assess the outcome are also absent: the statistical analysis plan, sample-size justification, missing-data approach, analysis population details, and any sensitivity analyses are not reported in the registry record. The registry records no analysis results. It is therefore not possible to assess the robustness of an endpoint estimate or the handling of multiple outcomes.

Safety interpretation is limited to the posted participant counts, the selected serious-event terms and percentages, and the reported death. Comparative safety data, event timing, event-level detail, and causal assessments are not reported in the stated information. These limitations mean the counts should be read as descriptive reports from the study group, not as evidence of comparative or attributable risk.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Study to Assess the Long-term Safety, Tolerability, and Efficacy of AMG 827 in Subjects With Psoriasis — NCT01101100.
• Registry record last updated 2019-07-30; status last verified 2019-07.
• Results first posted 2019-07-18.
• 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

The registry describes a Phase 2, open-label, single-group extension study of subcutaneous AMG 827 in subjects with psoriasis. It is identified as an extension of study 20090062. Enrollment is reported as 181; the study start is 2010-04, primary completion is 2015-09, and status is terminated.

The primary endpoint is the percentage with an sPGA assessment of clear or clear/almost clear at 264 weeks, among subjects with a valid measurement at the specified week. No numerical primary outcome result or analysis result is reported in the registry record. Safety information lists 29 participants affected by serious adverse events, 177 affected by other adverse events, and one death, with 181 at risk for each adverse-event category.

The record does not identify a concurrent control group. The reason for termination, missing-data handling, analysis methods, and the number with a valid week 264 measurement are not reported in the registry record. The posted information describes the study and reported safety experience but does not provide a controlled estimate of treatment effect.