This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Study to Assess Usability of Risankizumab Autoinjector Combination Product in Participants With Moderate to Severe Plaque Psoriasis (NCT03875508), a na phase 3 study. The primary outcome is Percentage of Participants With an Observer Rating of Successful Participant Self-administration.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03875508 |
| Phase | Phase 3 |
| Condition | Psoriasis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 108 |
| Arms in the primary outcome | n/a |
| Lead sponsor | AbbVie |
| Results posted | Yes |
2. Clinical Question
Population
Adults with moderate to severe plaque psoriasis. The primary endpoint population is defined as participants who received at least one dose of study drug and had available data.
Intervention
Risankizumab solution at 150 mg/mL, self-administered subcutaneously with a pre-filled autoinjector. The recorded schedule was Weeks 0, 4, 16, and 28.
Comparator
There was no separate comparator group. The study is recorded as single-group, with allocation listed as NA and masking listed as none.
Primary question
What percentage of participants were rated by an observer as successfully completing the required sequence of autoinjector steps on Day 1 and Week 28?
The primary question is about usability: whether participants could carry out the specified injection procedure without errors. The four critical steps were choosing an appropriate injection site, removing the autoinjector cap, activating the injection, and completing the injection. The observer rating therefore represents success across the whole sequence, not just completion of one selected step.
The study objectives also included evaluating efficacy, safety, and tolerability of risankizumab administered by autoinjector. Those objectives do not change the primary endpoint’s focus on the device-use sequence. With a single group and no control arm, the record describes experience with this product and procedure, rather than a randomized comparison with another device, administration method, or treatment.
3. Trial Design
This Phase 3 study is recorded as a completed, single-group study of risankizumab administered using an autoinjector. The registry lists 108 participants enrolled. It lists allocation as NA and masking as none; there is no separate comparator arm in the record. The study began on 2019-06-04, and primary completion was recorded as 2020-04-24.
The intervention description specifies risankizumab solution at 150 mg/mL, self-administered subcutaneously through a pre-filled autoinjector at Weeks 0, 4, 16, and 28. The primary outcome was assessed on Day 1 and Week 28. The endpoint description requires successful completion of all four critical steps in the Instructions for Use without errors, based on an observer rating.
The registry describes the primary endpoint population as the intent-to-treat population: participants who received at least one dose of study drug and had available data. This definition is narrower than simply all enrolled participants, because it includes a treatment-exposure requirement and an available-data requirement. Details of how missing observations were handled are not reported in the registry record.
The stated study objectives were to evaluate usability of the risankizumab-autoinjector combination product and to evaluate efficacy, safety, and tolerability for adults with moderate to severe plaque psoriasis. The record lists eight outcome measures and zero analyses. It does not report the primary endpoint’s observed percentage or an outcome estimate that would allow readers to quantify successful self-administration. It also does not report a statistical analysis plan or a sample-size justification.
Because there is no control group, the study design cannot estimate a treatment or device contrast against a concurrent alternative. The design can describe observations within the enrolled group, if those results are reported, but the registry record does not provide the primary usability result. The study’s completion status and enrollment describe the trial record; on their own, they do not establish the frequency of successful use or the precision of an estimate.
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: Intent-to-treat (ITT) population: all participants who received at least one dose of study drug
Overall Study
| Stage | Risankizumab |
|---|---|
| STARTED | 108 |
| COMPLETED | 96 |
| NOT COMPLETED | 12 |
Reasons for not completing this period:
| Reason | Risankizumab |
|---|---|
| Adverse Event | 1 |
| Lost to Follow-up | 8 |
| Lack of Efficacy | 1 |
| Other, not specified | 2 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-treat (ITT) population: all participants who received at least one dose of study drug and had available data
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: Intent-to-treat (ITT) population: all participants who received at least one dose of study drug
| Characteristic | Unit | Risankizumab |
|---|---|---|
| Participants analysed | 108 | |
| Age, Continuous | years | 49.2 (SD 14.32) |
| Sex: Female, Male: Female | Participants | 42 |
| Sex: Female, Male: Male | Participants | 66 |
| Race/Ethnicity, Customized: White | Participants | 95 |
| Race/Ethnicity, Customized: Black or African American | Participants | 5 |
| Race/Ethnicity, Customized: Asian | Participants | 7 |
| Race/Ethnicity, Customized: American Indian or Alaska Native | Participants | 1 |
| Race/Ethnicity, Customized: Native Hawaiian or other Pacific Islander | Participants | 0 |
| Race/Ethnicity, Customized: Other | Participants | 0 |
| Race/Ethnicity, Customized: Multiple | Participants | 0 |
| Race/Ethnicity, Customized: Missing | Participants | 0 |
| Prior Use of Systemic Biologic for Psoriasis: 0 | Participants | 60 |
| Prior Use of Systemic Biologic for Psoriasis: ≥1 | Participants | 48 |
| Static Physician Global Assessment (sPGA) Score at Baseline: Score of 3 | Participants | 88 |
| Static Physician Global Assessment (sPGA) Score at Baseline: Score of 4 | Participants | 20 |
| Psoriasis Area and Severity Index (PASI) Score at Baseline | units on a scale | 19.834 (SD 7.2424) |
| Body Surface Area (BSA) Psoriasis Involvement at Baseline | Percentage of body surface area affected | 25.471 (SD 17.4671) |
| Duration of Plaque Psoriasis | years | 16.89 (SD 13.095) |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With an Observer Rating of Successful Participant Self-administration, measured over Day 1 and Week 28.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with an observer rating of successful participant self-administration, assessed on Day 1 and Week 28. Success is defined as completing the sequence of four critical Instructions for Use steps without errors when administering study drug through the autoinjector. Those steps are choosing an appropriate injection site, removing the cap, activating the injection, and performing a complete injection.
This endpoint is used to assess whether participants can carry out the required device-use procedure, rather than whether a single step is performed correctly in isolation. Requiring successful completion of the full sequence makes the outcome directly relevant to usability of the combination product. The observer rating also means the endpoint is based on an assessment of the administration process, according to the stated definition.
The endpoint is expressed as a percentage of participants, so interpreting it requires knowing both how many participants met the success definition and the denominator used at each assessment. The registry defines the primary endpoint population as participants who received at least one dose and had available data. It does not report the observed endpoint percentage, the underlying counts, or a confidence interval. Consequently, the registry record does not establish how often participants met the four-step success criterion, or how precisely that rate was estimated.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main statistical issue is that the registry describes the primary outcome but does not report its observed value. The endpoint is a percentage of participants rated as completing all four critical injection steps without errors. Without the percentage or participant counts at Day 1 and Week 28, readers cannot quantify successful self-administration at either assessment or assess how the result may have changed over time.
The record lists 108 participants enrolled, but enrollment is not automatically the denominator for an endpoint analysis. The primary population is defined as participants who received at least one dose and had available data. The number meeting that definition at each assessment is not reported in the registry record. Nor are the numbers with successful or unsuccessful observer ratings. The enrolled total therefore cannot substitute for the endpoint-specific denominator.
There is also no reported uncertainty estimate for the primary outcome. In general, a confidence interval describes a range of values compatible with the observed data under a statistical method and indicates the precision of an estimate. For a participant percentage, precision depends in part on the number of usable observations and the observed rate. Since neither the endpoint estimate nor its interval is reported, the precision of the usability result cannot be assessed from the registry record.
The design is single-group, with no separate comparator. Accordingly, even a reported percentage would describe the observed group under the study conditions; it would not by itself establish how that percentage compares with another device, administration approach, or group of participants. The record lists no masking. Observer assessment is part of the stated endpoint, but details about observer procedures or any assessment safeguards are not reported in the registry record.
The record also lists efficacy, safety, and tolerability among the study objectives, but it does not give a primary usability estimate that can be interpreted alongside those objectives. The safety information that is recorded should be read separately from the usability endpoint: adverse-event counts do not supply evidence about successful completion of the injection sequence.
For the primary statistical question, the conclusion is therefore limited. The registry identifies the outcome definition, assessment times, and population definition, but not the result. No claim about the observed rate of successful administration or its precision can be drawn from those design details alone. The absence of a reported result is not evidence that success was high or low; it leaves the endpoint quantity unknown in this registry record.
9. Statistical Methods Explained
The primary outcome is a participant-level binary outcome: a participant either meets the stated success definition at an assessment or does not. The registry expresses the result as a percentage of participants. In general, a percentage for a binary outcome is calculated from the number of participants meeting the definition relative to the number with evaluable data for that assessment. The exact numerator and denominator are not reported in the registry record, so no endpoint percentage can be interpreted or reconstructed.
The success definition is conjunctive: the participant must complete all four critical steps without errors. A failure to meet any one required step means the full stated sequence has not been completed successfully. This kind of endpoint focuses on completion of the entire procedure. It is different from reporting success on individual steps, which could give a more detailed picture of where errors occurred. Separate step-level results are not reported in the registry record.
The outcome is assessed at two stated times, Day 1 and Week 28. In general, observations at distinct visits can describe usability at each time and may allow examination of patterns across visits when participant-level data and an analysis plan are available. However, the registry does not report the endpoint values at either time, whether the same participants contributed data at both assessments, or how within-participant observations were handled statistically. A difference or trend across assessments therefore cannot be evaluated from the record.
The primary population is labelled intent-to-treat and defined as all participants who received at least one dose of study drug and had available data. This operational definition should be read as written: it requires exposure to at least one dose and availability of data. It is not simply the total enrolled population, and the record does not say how many enrolled participants satisfied the definition. Details of how participants with missing assessments were handled are not reported in the registry record.
For a binary percentage, uncertainty is commonly summarized with a confidence interval. In general, the interval reflects sampling variability under its stated method; it is not a guarantee that the true value lies within the interval. The interval’s width depends on the data and the method used. No interval or method for calculating one is reported for this endpoint, so its precision cannot be judged. No test result or p-value for the primary outcome is reported either.
The registry lists zero analyses. This does not identify an analysis method, adjustment strategy, or inferential model for the primary endpoint. Such details, including any planned subgroup analyses, covariate adjustment, or handling of repeated observations, are not reported in the registry record. They should not be inferred from the endpoint’s percentage format or from the single-group design.
The record includes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. Such illustrations are planning exercises, not observed trial results and not evidence of the trial’s achieved power. The record’s trial itself is single-group, so a hypothetical two-arm planning framework does not create a randomized comparison in this study. The trial’s own sample-size justification is not reported in the registry record.
In general, over-dispersion matters when observed variation is greater than a model assumes; ignoring it can make uncertainty estimates too narrow. That concept is not a reported feature of this endpoint analysis, and the registry does not describe a model or dispersion assessment. The endpoint is a participant percentage, but that alone does not establish which inferential method was used. Statistical methods should therefore be interpreted only to the extent they are explicitly documented: the registry provides the endpoint definition, time points, and population description, but not the analysis details or primary estimate.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists eight outcome measures and zero analyses. It does not report a multiplicity strategy, such as a hierarchy of outcomes, adjustment across tests, or a distinction between confirmatory and exploratory analyses. The number of listed outcomes alone does not establish which outcomes were formally tested or whether any adjustment was planned. A statistical analysis plan is not reported in the registry record.
The primary endpoint is assessed on Day 1 and Week 28. How these two assessments relate to the primary analysis, including whether one time point was designated as the principal test or whether both were treated as co-primary, is not reported in the registry record. No test statistics or p-values for these assessments are reported.
The primary population is described as participants who received at least one dose and had available data. The registry does not give the number with available endpoint data at each assessment or explain how missing observations were handled. It does not report whether any imputation, sensitivity analysis, or other missing-data method was used. Without those details and endpoint counts, the effect of missing data on the estimated percentage cannot be assessed.
The record also does not report whether there were protocol deviations, exclusions after enrollment, or other analysis-population definitions beyond the stated primary population. The population definition should therefore be kept distinct from the total enrollment figure, and the precise analysis denominator remains unknown.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Risankizumab | 6 | 108 | 5.6% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Risankizumab | 0 of 108 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Risankizumab | 12 of 108 |
Most frequent serious adverse event terms
| Event term | Organ system | Risankizumab |
|---|---|---|
| ATRIAL FIBRILLATION | Cardiac disorders | 1 of 108 |
| PYREXIA | General disorders | 1 of 108 |
| APPENDICITIS | Infections and infestations | 1 of 108 |
| PYELONEPHRITIS | Infections and infestations | 1 of 108 |
| THERMAL BURN | Injury, poisoning and procedural complications | 1 of 108 |
| LUMBAR SPINAL STENOSIS | Musculoskeletal and connective tissue disorders | 1 of 108 |
| PROSTATITIS | Reproductive system and breast disorders | 1 of 108 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Risankizumab |
|---|---|---|
| NASOPHARYNGITIS | Infections and infestations | 8 of 108 |
| UPPER RESPIRATORY TRACT INFECTION | Infections and infestations | 6 of 108 |
Serious events with the highest arm-level rate: atrial fibrillation (0.9%), pyrexia (0.9%), appendicitis (0.9%), pyelonephritis (0.9%), thermal burn (0.9%).
The registry lists 108 participants at risk for serious adverse events in the risankizumab group and 6 participants affected. It lists 108 at risk for other adverse events and 12 affected. The recorded number of deaths is 0. These are safety counts for the group, not results for the primary usability endpoint.
The listed serious adverse event terms are atrial fibrillation, pyrexia, appendicitis, pyelonephritis, thermal burn, and lumbar spinal stenosis; each is recorded as 0.9%. The registry does not give additional event-level detail in these entries, so they should be read as the terms and percentages recorded, not as a complete account of clinical context, timing, severity, or relatedness.
Counts of affected participants are not necessarily the same as counts of events, because one participant can experience more than one event. The registry entries do not clarify event-level totals or provide further detail about overlap. These figures describe what is recorded for this study group; with no control group, they do not provide a like-for-like comparative estimate.
12. What the Result Does, and Does Not, Mean
The record establishes the study’s central usability question and how success was defined: an observer-rated, error-free completion of four critical autoinjector steps. It also identifies the assessment times, Day 1 and Week 28, and describes the primary population. These details allow readers to understand what the endpoint was intended to measure.
However, the primary outcome value is not reported in the registry record. The record does not state the percentage of participants rated successful at either assessment, the corresponding counts, or an uncertainty interval. Thus, the available information does not show how often the required injection sequence was completed successfully or how precisely that frequency was estimated.
The single-group design also limits what the study could establish comparatively. There is no separate control arm, and the record lists no masking. Any within-group outcome, if reported, would describe observations under this study’s conditions. It would not, on its own, quantify a difference from another device or administration method. The registry’s objectives include efficacy, safety, and tolerability, but the missing primary usability estimate cannot be replaced by the safety entries.
The safety record lists affected participants and several serious adverse event terms, but those observations answer a different question from whether the injection steps were completed without error. The recorded safety counts should not be treated as measures of device usability or as evidence of a comparative effect.
In general, a well-defined endpoint is necessary for interpretation, but it is not sufficient: readers also need the observed data, analysis denominator, and an indication of statistical uncertainty. Here, the endpoint definition is available, while those central result details are not. The appropriate interpretation is therefore bounded by the registry record: it documents what the study set out to assess, but not the primary endpoint result needed to characterize observed usability.
13. Why This Trial Matters Statistically
This study raises a statistical question that is distinct from a conventional treatment-versus-control efficacy comparison. Its primary endpoint concerns whether participants can carry out a multi-step administration procedure without errors. That makes the definition and measurement of success central: the registry specifies four required steps and an observer rating, rather than relying on a general impression of ease of use.
The endpoint’s timing also matters. An assessment on Day 1 and another at Week 28 could describe usability at different points in the recorded dosing schedule. To interpret change across time, readers would need the outcome at both visits, the number assessed at each, and a description of how observations from the same participants were analyzed. Those result and method details are not reported in the registry record.
The study also illustrates why a total enrollment figure is not an endpoint denominator. The primary population requires at least one dose and available data; endpoint-specific counts are needed to interpret a percentage and its precision. Without them, enrollment cannot establish the number of evaluable observations.
Finally, a single-group usability study and a hypothetical two-arm planning illustration are different things. Planning assumptions can illustrate what might be needed for a future comparison, but they do not convert this study into a controlled comparison or supply its missing endpoint estimate. The registry record identifies the usability question clearly, while leaving the numerical result and its uncertainty unreported.
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 primary limitation for interpretation is that the registry does not report the observed percentage for the primary endpoint, participant counts, or a confidence interval. Although the outcome definition and assessment times are stated, the result and its precision cannot be evaluated from the record.
The study is recorded as single-group, with allocation listed as NA and masking listed as none. There is no concurrent control group for comparison. The registry does not report details of observer training, observer procedures, or whether assessments were independently checked; these aspects should not be assumed.
The endpoint population requires participants to have received at least one dose and have available data. The number meeting that definition at Day 1 and Week 28, and the handling of missing observations, are not reported in the registry record. This leaves the endpoint-specific denominator and possible influence of unavailable data unclear.
The registry lists eight outcome measures but zero analyses. It does not report a statistical analysis plan, multiplicity handling, inferential methods, or a sample-size justification. It also does not provide enough information to assess whether the two assessment times were analyzed separately or jointly.
Finally, the registry describes efficacy, safety, and tolerability as objectives, but the available record does not provide a primary usability estimate. The recorded safety figures concern a single group and are not a comparative safety analysis. These limitations constrain interpretation of the registry record; they do not establish what the unreported results would have been.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study to Assess Usability of Risankizumab Autoinjector Combination Product in Participants With Moderate to Severe Plaque Psoriasis — NCT03875508.
- Registry record last updated 2021-05-11; status last verified 2021-04.
- Results first posted 2021-05-11.
- 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.
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18. Record Summary
This completed Phase 3 study enrolled 108 participants with moderate to severe plaque psoriasis and evaluated risankizumab administered through a pre-filled autoinjector. The recorded dosing schedule was Weeks 0, 4, 16, and 28. The study was single-group, with allocation listed as NA and masking listed as none.
The primary outcome was the percentage of participants with an observer rating of successful self-administration on Day 1 and Week 28. Success required completing four critical injection steps without errors. The primary population was defined as participants who received at least one dose and had available data.
The primary endpoint result and its uncertainty are not reported in the registry record. The record lists safety counts of 6 participants affected by serious adverse events and 12 affected by other adverse events among 108 at risk in each category, with 0 deaths recorded.