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 of Ixekizumab (LY2439821) in Participants Aged ≥18 Years With Moderate-to-Severe Plaque or Active Psoriatic Arthritis in India (NCT05855967), a na phase 4 study. The primary outcome is Number of Participants Reporting Serious Adverse Events (SAEs), and Treatment Emergent Adverse Events (TEAEs) and AEs of Special Interests (AESIs) From Week 0 to Week 24.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05855967 |
| Phase | Phase 4 |
| Condition | Plaque Psoriasis, Psoriatic Arthritis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 250 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Eli Lilly and Company |
| Results posted | Yes |
2. Clinical Question
Population
Adults aged 18 years or older in India with moderate-to-severe plaque psoriasis or active psoriatic arthritis. The registry describes a plaque-psoriasis group without active psoriatic arthritis and a group with active psoriatic arthritis and moderate-to-severe plaque psoriasis.
Intervention
Ixekizumab, administered by subcutaneous injection. The registry describes different dosing regimens, including a Q2W/Q4W regimen and a Q4W regimen.
Comparator
There was no separate control group. The study is recorded as single-group, open-label, and non-randomized. The dosing-regimen groups are not described as like-for-like controls.
Primary question
How many treated participants reported serious adverse events, treatment-emergent adverse events, or adverse events of special interest from Week 0 to Week 24?
The central question is about safety and tolerability during treatment, not a comparison of ixekizumab with another treatment or with no treatment. The primary outcome is a count of participants with specified events during the stated period. The registry defines a serious adverse event by whether it meets criteria such as death, life threat, inpatient hospitalization, persistent disability, or a congenital anomaly. A treatment-emergent adverse event is one that first occurs or worsens after baseline and by the last visit within the treatment period.
The registry also lists secondary outcomes for psoriasis response and psoriatic arthritis response. These include PASI-75 at Week 12, a clear or minimal static physician global assessment, and ACR20 at Week 24. They address clinical response rather than the primary safety question. Numerical results for those outcomes are not reported in the registry record, so the record cannot answer how often participants met those response thresholds.
3. Trial Design
This was a completed Phase 4, multicenter, open-label, single-group study in India. The official title describes a 24-week study of ixekizumab in participants with moderate-to-severe plaque psoriasis or active psoriatic arthritis. The registry lists 250 participants as the enrollment figure. The study start date is 2023-06-27, and the primary completion date is 2024-08-08.
There was no randomized allocation and no masking. The study therefore does not provide a randomized contrast between ixekizumab and a control treatment. The registry presents safety results separately for two ixekizumab dosing regimens: Q2W/Q4W and Q4W. These regimen groups are not described as randomized arms, and their figures should not be interpreted as a treatment-versus-control comparison. The registry record does not report how participants came to receive one regimen rather than the other.
The posted primary safety period runs from Week 0 to Week 24. The safety population is described as participants who received at least one dose of study treatment. The record states that adverse events were collected and analyzed by ixekizumab dosing regimen. The listed regimen descriptions include an initial 160 mg subcutaneous dose and subsequent 80 mg doses, but the descriptions are truncated in the registry record; a complete schedule is not reported there.
The study has a safety focus, while its listed secondary outcomes concern psoriasis and psoriatic arthritis response. The registry record does not report a sample-size justification, a statistical analysis plan in full, or the detailed procedures used to assign regimens. Those omissions limit assessment of how the study was planned and how the separate regimen groups should be interpreted.
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
| Stage | Ixekizumab - PsO With no Active PsA | Ixekizumab - Active PsA |
|---|---|---|
| STARTED | 150 | 100 |
| Received at Least One Dose of Study Drug | 150 | 100 |
| Q2W/Q4W Ixekizumab Dosing Regimen | 150 | 59 |
| Q4W Ixekizumab Dosing Regimen | 0 | 41 |
| COMPLETED | 141 | 94 |
| NOT COMPLETED | 9 | 6 |
Reasons for not completing this period:
| Reason | Ixekizumab - PsO With no Active PsA | Ixekizumab - Active PsA |
|---|---|---|
| Withdrawal by Subject | 7 | 5 |
| Lost to Follow-up | 2 | 1 |
Analysis population for the primary outcome, as defined in the registry: All participants who received at least 1 dose of study treatment. As per prespecified analysis in the statistical analysis plan, adverse events were collected and analyzed by ixekizumab dosing regimen \[that is, Q2W/Q4W and Q4W\].
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: All enrolled participants who received at least one dose of study treatment.
| Characteristic | Unit | Ixekizumab - PsO With no Active PsA | Ixekizumab - Active PsA | Total |
|---|---|---|---|---|
| Participants analysed | 150 | 100 | 250 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 141 | 92 | 233 |
| Age, Categorical: >=65 years | Participants | 9 | 8 | 17 |
| Sex: Female, Male: Female | Participants | 28 | 33 | 61 |
| Sex: Female, Male: Male | Participants | 122 | 67 | 189 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 | 0 | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 8 | 20 | 28 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 142 | 80 | 222 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 150 | 100 | 250 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): White | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): More than one race | Participants | 0 | 0 | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 |
| Region of Enrollment: India | Participants | 150 | 100 | 250 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Reporting Serious Adverse Events (SAEs), and Treatment Emergent Adverse Events (TEAEs) and AEs of Special Interests (AESIs) From Week 0 to Week 24, measured over Week 0 to Week 24.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who reported serious adverse events, treatment-emergent adverse events, and adverse events of special interest from Week 0 to Week 24. It is a participant count, rather than a measure of how many events each participant experienced or how long participants were exposed before an event. A participant with more than one event is still counted as a participant for a participant-level outcome; the registry does not provide event-level totals in the posted primary results.
The registry defines a serious adverse event using consequences such as death, a life-threatening occurrence, inpatient hospitalization or prolongation of hospitalization, persistent disability or incapacity, or congenital anomaly or birth defect. A treatment-emergent adverse event is defined as an event first occurring or worsening in severity after baseline and on or before the last visit within the treatment period. The record identifies adverse events of special interest as part of the primary endpoint but does not give their operational definition in the posted endpoint description.
Safety endpoints of this kind are used to describe events observed during exposure and to identify events warranting attention in further evaluation. Counts are descriptive: without a control group, they do not establish how many events would have occurred in the absence of treatment or under another treatment. Interpretation also depends on the population observed, follow-up, event definitions, and completeness of reporting. The registry’s primary endpoint is framed around participants receiving at least one dose and a fixed Week 0 to Week 24 period.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted serious-event counts are 1 participant in the Q2W/Q4W ixekizumab dosing regimen group, with 209 at risk, and 0 participants in the Q4W ixekizumab dosing regimen group, with 41 at risk. These are descriptive counts from the treated groups. They do not establish a difference between regimens: the study is single-group and non-randomized, and the record does not describe the groups as an exchangeable comparison.
The registry also reports 66 participants with other events among 209 at risk in the Q2W/Q4W group, and 9 among 41 at risk in the Q4W group. These figures should be read in the categories recorded, not as a complete account of event frequency, severity, timing, or duration. The posted results do not provide a separate numerical breakdown for each component of the composite primary endpoint. The record lists viral gastroenteritis at 0.5% among the top serious-event terms and reports 0 deaths in each regimen group.
Counts depend on who entered the safety population and how long each participant was observed. The registry defines that population as participants who received at least one dose, but the posted results do not give individual follow-up time or detail withdrawals and missing safety assessments. A count of participants affected therefore cannot by itself show event rates over time or account for differences in exposure duration.
The listed secondary measures could describe psoriasis or arthritis response, but their numerical results are not reported in the registry record. No inferential estimates or confidence intervals are reported for the posted safety figures. Consequently, the precision of the observed counts cannot be quantified from the record, and the counts should not be treated as precise estimates of underlying risks.
More generally, an open-label, non-randomized safety study can document events observed during treatment, but it cannot isolate the treatment’s causal contribution to those events. Differences between the regimen groups could reflect how participants were selected, their clinical characteristics, exposure, follow-up, or other factors. The registry record does not report enough detail to assess those possibilities. The appropriate reading is a descriptive account of recorded events in the treated groups over the stated period, not proof of comparative safety or effectiveness.
9. Statistical Methods Explained
The registry describes the primary outcome as a count of participants and identifies the outcome type as binary. In general, a participant-level binary outcome records whether each participant did or did not meet a defined event criterion during the observation period. Summarizing such an outcome as a count helps communicate how many participants were affected, while the at-risk denominator gives the size of the group in which events were assessed. It does not show the number of separate event episodes.
What does a participant count capture?
For safety, a participant count answers whether an individual had at least one qualifying event within the defined period. If one participant experiences repeated events, a participant-level count does not distinguish that from one event. Event counts, event rates, time to first event, and participant counts answer different questions. The registry’s primary measure is the last of these. The posted record does not report event-level totals or time-to-event estimates.
The endpoint also groups several safety concepts: serious adverse events, treatment-emergent adverse events, and adverse events of special interest. These categories can overlap, and the record does not provide a separate numerical result for each component. Seriousness refers to specified consequences or criteria, while treatment-emergent status concerns when an event begins or worsens relative to baseline and the treatment period. Those labels should not be treated as interchangeable.
Why does the absence of randomization matter?
In general, random allocation is used to make treatment groups comparable, on average, with respect to measured and unmeasured factors. This study is recorded as non-randomized and single-group, with safety results separated by dosing regimen. The regimen categories therefore do not create a randomized control comparison. Differences in their observed counts could arise from differences in who received each regimen, follow-up, exposure, or other characteristics. The registry does not report enough information to determine whether these factors differed or how they were handled.
An open-label design means masking was not used. For many safety outcomes, events may be based on participant reports, clinical observation, or both. In general, knowledge of treatment can affect how symptoms are reported, elicited, classified, or investigated. The registry record does not describe specific steps used to limit such effects, so no conclusion about their presence or size is possible.
What can precision measures add?
In general, a confidence interval expresses the range of values compatible with observed data under a statistical model and indicates uncertainty around an estimate. It does not remove bias from a non-randomized comparison or account automatically for incomplete follow-up. No confidence intervals or other inferential estimates for the posted safety counts are reported in the registry record. The count and at-risk denominator can be read as descriptive observations, but they do not quantify uncertainty around an underlying event probability.
For binary outcomes, methods may use a binomial model, with alternatives chosen when assumptions such as independence or a common event probability are unsuitable. For repeated or clustered observations, analyses may need to account for dependence; for counts with variability greater than a simple model expects, methods addressing over-dispersion may be relevant. These are general statistical considerations, not claims about methods used in this study. The registry record does not report the specific estimator, model, or inferential procedure for these outcomes.
How should the planning illustration be read?
The registry describes planning illustrations based on a stated fraction of an observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It specifies that such illustrations are planning calculations, not the trial’s own design or observed power. This study itself is single-group, and the illustration’s equal-allocation assumption does not describe the recorded design. A planning sample size is a prospective calculation under assumptions; it is not a measure of the probability that the completed study detected an effect. The registry record does not report a trial-specific sample-size justification.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists several secondary outcomes in addition to the primary safety endpoint. These include PASI-75 at Week 12, a static physician global assessment of clear or minimal, and ACR20 at Week 24. When multiple outcomes are tested, the chance of at least one apparently notable result can increase if no multiplicity strategy is used. In general, a prespecified approach may control that risk, prioritize outcomes, or treat secondary results as exploratory.
The registry record does not report a multiplicity adjustment, a hierarchy among outcomes, or the statistical testing plan for the secondary measures. It also reports no analyses for those listed secondary outcomes. Their numerical results and any associated uncertainty are not reported in the registry record, so no claim about their findings or statistical significance is warranted.
The safety population is defined as participants who received at least one dose, and the record states that adverse events were analyzed by dosing regimen. Details about missing safety information, incomplete follow-up, withdrawals, and the handling of missing observations are not reported in the registry record. This matters because descriptive counts rely on knowing who was assessed and for what period. Without those details, the potential influence of missing or unequal observation cannot be evaluated.
The record identifies the safety analysis population and regimen grouping, but a fuller statistical analysis plan, including missing-data rules and multiplicity procedures, is not reported in the registry record. That absence limits reproducibility and the assessment of whether the posted outcome definitions and analyses were prespecified in detail.
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 |
|---|---|---|---|
| Q2W/Q4W Ixekizumab Dosing Regimen | 1 | 209 | 0.5% |
| Q4W Ixekizumab Dosing Regimen | 0 | 41 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Q2W/Q4W Ixekizumab Dosing Regimen | 0 of 209 |
| Q4W Ixekizumab Dosing Regimen | 0 of 41 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Q2W/Q4W Ixekizumab Dosing Regimen | 66 of 209 |
| Q4W Ixekizumab Dosing Regimen | 9 of 41 |
Most frequent serious adverse event terms
| Event term | Organ system | Q2W/Q4W Ixekizumab Dosing Regimen | Q4W Ixekizumab Dosing Regimen |
|---|---|---|---|
| Gastroenteritis viral | Infections and infestations | 1 of 209 | 0 of 41 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Q2W/Q4W Ixekizumab Dosing Regimen | Q4W Ixekizumab Dosing Regimen |
|---|---|---|---|
| Latent tuberculosis | Infections and infestations | 18 of 209 | 4 of 41 |
| Pyrexia | General disorders | 18 of 209 | 1 of 41 |
| Injection site erythema | General disorders | 4 of 209 | 1 of 41 |
| Nasopharyngitis | Infections and infestations | 3 of 209 | 1 of 41 |
| Tinea cruris | Infections and infestations | 3 of 209 | 0 of 41 |
| Upper respiratory tract infection | Infections and infestations | 2 of 209 | 1 of 41 |
| Blood creatine phosphokinase increased | Investigations | 3 of 209 | 0 of 41 |
| Hypertriglyceridaemia | Metabolism and nutrition disorders | 3 of 209 | 0 of 41 |
| Body tinea | Infections and infestations | 2 of 209 | 0 of 41 |
| Urinary tract infection | Infections and infestations | 0 of 209 | 2 of 41 |
Serious events with the highest arm-level rate: gastroenteritis viral (0.5%).
The serious-event results are participant counts within each regimen group. In the Q2W/Q4W group, 1 participant was affected among 209 at risk; in the Q4W group, 0 participants were affected among 41 at risk. The registry reports 0 deaths in each group. These observations describe what was recorded in this study during Week 0 to Week 24; they are not a comparison against an untreated or randomized control group.
The record also lists viral gastroenteritis at 0.5% among the top serious-event terms. That listing does not provide a full account of all serious-event types or their clinical details. The other-event counts are 66 among 209 at risk in the Q2W/Q4W group and 9 among 41 at risk in the Q4W group. Those counts should not be conflated with the serious-event counts or assumed to describe event episodes.
Small or zero counts do not establish that an event cannot occur. The record does not report confidence intervals, event timing, individual exposure duration, or detailed missing-data information for these figures. They are best read as descriptive safety observations from the recorded treated population, with uncertainty and limitations in interpretation.
12. What the Result Does, and Does Not, Mean
The results describe adverse events recorded among participants who received at least one dose of ixekizumab, with the primary safety period defined as Week 0 to Week 24. The registry reports serious-event and other-event counts by dosing regimen, along with 0 deaths in each group. These observations contribute a description of safety during the study period in the enrolled clinical setting.
They do not show what would have happened to the same participants without ixekizumab, or under another treatment. There is no randomized control group, and the registry does not establish that the regimen groups were comparable. Thus, differences in the counts cannot be attributed to the dosing regimen on the basis of this record alone. Nor do the counts establish that a treatment caused or prevented any individual event.
The primary outcome is a count of participants with events, not a full account of the number, duration, recurrence, or timing of events. The available summary also does not provide uncertainty intervals or detailed follow-up and missing-data information. Those omissions limit conclusions about how precisely the observed counts represent event experience beyond the recorded participants.
The secondary outcomes concern psoriasis and psoriatic arthritis response, but numerical results are not reported in the registry record. Therefore, this record does not support a conclusion about those outcomes. More broadly, a safety-focused study without a control group can document observed events and support further assessment, but the design and reported results do not establish comparative safety or treatment benefit.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how safety outcomes are reported in a single-group study. The primary measure is a participant count over a defined period, and results are stratified by dosing regimen. That framing makes clear what was observed in each recorded group while also underscoring the limits of a non-randomized design.
The distinction between a count and a rate is important. Counts reflect the number of participants meeting an event definition, while rates also require information about exposure time. The registry gives at-risk denominators, but the posted summary does not provide individual follow-up time or time-to-event analyses. A participant count cannot by itself adjust for differences in duration of observation.
The record also illustrates why a named primary endpoint may combine distinct safety categories. Seriousness, treatment emergence, and special-interest status refer to different attributes, and a combined endpoint may be difficult to interpret without separate component results. The registry gives definitions for serious and treatment-emergent events, but the posted results do not provide a complete numerical breakdown across all components.
Finally, the contrast between the trial design and the planning illustration matters. The study is single-group, whereas the registry describes sample-size illustrations based on equal allocation between two arms. Such planning calculations do not make the study a comparative trial and are not evidence of observed power. Clear separation of design, observed descriptive results, and hypothetical planning assumptions is essential for sound statistical interpretation.
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 main design limitation is the absence of randomization and a separate control group. The regimen groups are not described as like-for-like controls, and the registry does not report how treatment regimens were selected. Consequently, their safety counts cannot establish comparative effects or support a causal interpretation.
The registry reports event counts but not confidence intervals, event rates over exposure time, event timing, recurrence, or detailed participant-level follow-up. It also does not report a separate numerical result for every component of the primary endpoint. This restricts assessment of precision and of the different types of event contributing to the safety summary.
Details on missing safety assessments, withdrawals, and the handling of incomplete follow-up are not reported in the registry record. The endpoint description identifies a population that received at least one dose, but the posted information does not allow a fuller assessment of how observation varied across participants. The listed dosing schedules are also incomplete in the registry record.
Numerical findings for the listed psoriasis and psoriatic arthritis response outcomes are not reported. The statistical analysis plan, multiplicity strategy, and trial-specific sample-size justification are not reported in the registry record. These limitations do not negate the descriptive safety counts, but they restrict the questions those counts can answer and the confidence with which they can be generalized.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Ixekizumab (LY2439821) in Participants Aged ≥18 Years With Moderate-to-Severe Plaque or Active Psoriatic Arthritis in India — NCT05855967.
- Registry record last updated 2025-08-22; status last verified 2025-08.
- Results first posted 2025-08-22.
- 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
The registry record describes NCT05855967, a completed, multicenter, open-label, single-group Phase 4 study of ixekizumab in India. The enrollment figure is 250. The study started on 2023-06-27 and reached primary completion on 2024-08-08. The primary safety outcome counts participants with serious adverse events, treatment-emergent adverse events, and adverse events of special interest from Week 0 to Week 24.
Safety results are reported by Q2W/Q4W and Q4W ixekizumab dosing regimen. The record lists 1 serious-event participant among 209 at risk in the Q2W/Q4W group and 0 among 41 at risk in the Q4W group; deaths are reported as 0 in each group. It also lists other-event counts and a serious-event term. Numerical results for the listed secondary response outcomes are not reported in the registry record. The non-randomized design supports descriptive reading of the safety observations, not a controlled treatment comparison.