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 Safety and Effectiveness of Rilonacept for Treating Systemic Juvenile Idiopathic Arthritis in Children and Young Adults (NCT00534495), a randomized phase 2 study. The primary outcome is Time to Response to Treatment, as Determined by a Modified JIA ACR30 Requiring no Fever, Coupled With a Requirement for Corticosteroid Taper in Participants Who Are Taking Corticosteroids.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00534495 |
| Phase | Phase 2 |
| Condition | Juvenile Idiopathic Arthritis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 71 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Montefiore Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
Children and young adults with systemic juvenile idiopathic arthritis (SJIA) were the intended population. The registry record describes SJIA as a form of arthritis that typically occurs before 16 years of age, but a specific age range or detailed eligibility criteria are not reported in the registry record.
Intervention
The immediate-start group received a rilonacept loading dose of 4.4mg/kg at Week 0, followed by 2.2 mg/kg/week for the remainder of the study.
Comparator
The comparison group received placebo for 4 weeks, then a rilonacept loading dose of 4.4mg/kg, followed by 2.2 mg/kg/week for the remainder of the study. The comparison therefore concerns starting rilonacept immediately versus delaying its start for 4 weeks, rather than a continuing placebo comparison.
Primary question
The primary endpoint asks how long it takes to reach a modified JIA ACR30 response requiring no fever, with a corticosteroid-taper requirement for participants taking corticosteroids. The registry reports median time to response at Week 12 for each group. It does not report an inferential estimate comparing the groups.
The trial was designed to address the timing of rilonacept initiation in SJIA. Its posted primary results are descriptive medians and inter-quartile ranges: 4.0 weeks (2.0 to 10.0) for the immediate-start group and 8.0 weeks (6.0 to not reported) for the placebo-first group. These values describe the recorded response times; they do not, by themselves, establish the size or precision of a between-group effect. The registry record does not report a hazard ratio, confidence interval, or p-value for this primary endpoint.
3. Trial Design
This was a randomized, quadruple-masked, parallel-group Phase 2 study. The registry record lists Montefiore Medical Center as sponsor and reports enrollment of 71. The study is marked completed. Its start is recorded as 2008-11 and primary completion as 2013-06. The registry record does not describe which parties were masked, how the randomization sequence was generated, or the allocation ratio.
The two groups differed during the first 4 weeks. One began rilonacept at Week 0 with a loading dose of 4.4mg/kg and continued with 2.2 mg/kg/week. The other received placebo for 4 weeks before starting the same rilonacept regimen. Thus, the principal contrast is early versus delayed initiation. After the placebo period, both groups were scheduled to receive rilonacept; this design does not provide a continuing untreated comparison across the full study period.
The primary endpoint was assessed at Week 12 and measured time to a modified JIA ACR30 response with a no-fever requirement. For participants taking corticosteroids, the endpoint also required a corticosteroid taper. The registry lists secondary outcomes involving JIA ACR50 and JIA ACR70 response, the Pediatric Quality of Life Inventory, physical function measured with the Childhood Health Assessment Questionnaire, and presence of systemic features including fever and rash. Four secondary outcomes are posted.
The registry record does not report the detailed protocol, eligibility criteria, planned follow-up schedule for each outcome, or the reasons for any participant not contributing to an endpoint. The posted group sizes for the primary outcome are 36.0 and 35.0. The safety record includes additional risk sets for later study periods, which should be read separately from the primary-outcome group sizes.
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: 71 participants enrolled. 1 participant was erroneously randomized and was not included in the analysis. This patient was not exposed to study drug
Double Blind Placebo Phase Week 0-4
| Stage | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| STARTED | 36 | 35 | 0 |
| COMPLETED | 36 | 34 | 0 |
| NOT COMPLETED | 0 | 1 | 0 |
Reasons for not completing this period:
| Reason | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| randomized in error | 0 | 1 | 0 |
All Active Treatment Phase Week 4-24
| Stage | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| STARTED | 36 | 34 | 0 |
| COMPLETED | 32 | 25 | 0 |
| NOT COMPLETED | 4 | 9 | 0 |
Reasons for not completing this period:
| Reason | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| Adverse Event | 1 | 0 | 0 |
| Lack of Efficacy | 1 | 7 | 0 |
| Lost to Follow-up | 1 | 1 | 0 |
| Withdrawal by Subject | 1 | 1 | 0 |
Long Term Ext. Phase Week 24-month 21
| Stage | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| STARTED | 0 | 0 | 40 |
| COMPLETED | 0 | 0 | 29 |
| NOT COMPLETED | 0 | 0 | 11 |
Reasons for not completing this period:
| Reason | Rilonacept | Placebo | Long Term Extension All Participants |
|---|---|---|---|
| Adverse Event | 0 | 0 | 1 |
| Lack of Efficacy | 0 | 0 | 5 |
| Withdrawal by Subject | 0 | 0 | 3 |
| non compliance | 0 | 0 | 2 |
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.
| Characteristic | Unit | Rilonacept | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 36 | 35 | 71 | |
| Age, Continuous | years | 9.5 (SD 4.6) | 10.5 (SD 4.4) | 10 (SD 4.5) |
| Sex: Female, Male: Female | Participants | 23 | 23 | 46 |
| Sex: Female, Male: Male | Participants | 13 | 12 | 25 |
| Race/Ethnicity, Customized: Black | Participants | 5 | 7 | 12 |
| Race/Ethnicity, Customized: White | Participants | 25 | 23 | 48 |
| Race/Ethnicity, Customized: Other | Participants | 6 | 5 | 11 |
| Race/Ethnicity, Customized: Hispanic | Participants | 7 | 5 | 12 |
| Race/Ethnicity, Customized: Non-Hispanic | Participants | 29 | 30 | 59 |
| Disease Duration | years | 2.6 (SD 3.6) | 2.6 (SD 3.1) | 2.6 (SD 3.4) |
| No.of joints with active disease | joints | 11.7 (SD 9.6) | 10.5 (SD 7.6) | 11.1 (SD 8.6) |
| Prior medications: Corticosteroids | participants | 30 | 33 | 63 |
| Prior medications: Methotrexate | participants | 21 | 26 | 47 |
| Prior medications: Leflunomide | participants | 1 | 2 | 3 |
| Prior medications: Infliximab | participants | 5 | 6 | 11 |
| Prior medications: Etanercept | participants | 12 | 16 | 28 |
| Prior medications: Abatacept | participants | 5 | 4 | 9 |
| Prior medications: Anakinra | participants | 13 | 13 | 26 |
| Prior medications: unknown Anakinra | participants | 4 | 4 | 8 |
| Disease characteristics in the past: Incomplete Macrophage Activation Syndrome | participants | 1 | 3 | 4 |
| Disease characteristics in the past: Complete Macrophage Activation Syndrome | participants | 1 | 1 | 2 |
| Disease characteristics in the past: Serositis | participants | 9 | 8 | 17 |
| Disease characteristics in the past: Systemic JIA rash | participants | 32 | 33 | 65 |
6. Primary Endpoint
The registry lists the primary outcome as Time to Response to Treatment, as Determined by a Modified JIA ACR30 Requiring no Fever, Coupled With a Requirement for Corticosteroid Taper in Participants Who Are Taking Corticosteroids, measured over At Week 12.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Inter-Quartile Range |
| Unit | weeks |
| Endpoint classification | Time-to-Event Analysis |
The primary endpoint is time to response, measured in weeks. A response was defined using a modified JIA ACR30 criterion, with an additional requirement for no fever. Participants taking corticosteroids also had to meet a corticosteroid-taper requirement. The endpoint therefore combines a clinical response definition with requirements related to systemic symptoms and, for some participants, corticosteroid use.
Time-to-response outcomes capture how long it takes for an event—in this case, meeting the specified response definition—to occur. Reporting a median gives the time by which half of the observed response times fall at or before that point, subject to the way the analysis handles participants who do not have an observed response. The registry record does not describe that handling or the analysis population.
The registry reports the endpoint at Week 12. The immediate-start group has a median of 4.0 weeks and an inter-quartile range of 2.0 to 10.0 weeks. The placebo-first group has a median of 8.0 weeks; its reported lower quartile is 6.0 weeks, while the upper quartile is not reported. An inter-quartile range describes the middle half of the observed times and is not a confidence interval for the median or for a treatment contrast.
This endpoint is useful for describing the timing of a defined response, rather than only whether response was recorded by a particular point. However, without a reported between-group estimate and its uncertainty, the medians alone do not establish how precisely the groups differ.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted primary results give a median time to response of 4.0 weeks (inter-quartile range 2.0 to 10.0) in the group that began rilonacept at Week 0. In the group that began with placebo, the median is 8.0 weeks, with a reported lower quartile of 6.0 weeks and no reported upper quartile. These are summaries of the observed time-to-response data at Week 12, not a complete statistical comparison between randomized groups.
The difference between two medians cannot be interpreted on its own as an adjusted or inferential treatment effect. The registry record does not report a hazard ratio, confidence interval, p-value, or other estimate quantifying the between-group contrast for this endpoint. It also does not report the number of participants with an observed response or the number whose response time was censored. A reader therefore cannot assess from these summaries alone how much uncertainty surrounds the comparison or how participants without a recorded response were handled.
The missing upper quartile for the placebo-first group also limits interpretation of its spread. The median remains reported, but the middle-half range cannot be fully described from the registry record. The inter-quartile range for the immediate-start group describes variation in observed response times; it is not evidence about the precision of the difference between groups.
The study’s design is relevant to the contrast. The placebo group received active rilonacept after 4 weeks, so the comparison is early initiation versus a 4-week delay, not rilonacept versus placebo throughout follow-up. Results during later periods may reflect treatment exposure in both groups and should not be read as the same contrast as the initial randomized period.
The safety record reports serious adverse events across several periods. During Weeks 0–4, 1 participant among 36 at risk in the rilonacept group and 1 among 35 at risk in the placebo group were affected. During Weeks 4–24, the corresponding figures are 3 among 35 and 1 among 33. In the long-term extension from 24 weeks to 21 months, 6 among 40 were affected. These counts describe the posted risk sets and periods; they do not establish that a treatment caused an event or support a simple comparison across periods with different exposure histories.
Overall, the record presents descriptive endpoint and safety summaries but does not supply the inferential result needed to quantify the primary randomized contrast. Interpretation should remain limited to what those summaries report.
9. Statistical Methods Explained
Several statistical ideas help distinguish the posted summaries from a formal estimate of the study’s primary comparison. The registry record reports medians and inter-quartile ranges for a time-to-response endpoint, but no between-group inferential result for that endpoint.
What does a median time describe?
A median is the central value of a distribution: half of the observed times lie at or before it and half at or after it, subject to the analysis definition. For time-to-event data, not every participant necessarily has an observed event during follow-up. Some participants may have an event time that is unknown because observation ends first or because they leave the study. Statistical methods for time-to-event outcomes can retain information from such participants by accounting for censoring. The registry record does not report whether or how censoring was handled for this endpoint, so the median summaries cannot be used to reconstruct the analysis.
The posted medians are 4.0 weeks for the immediate-start group and 8.0 weeks for the placebo-first group. They are descriptive values, not a direct estimate of the probability of response over time, and not a measure of uncertainty about the between-group contrast. The inter-quartile range gives the span from the lower to upper quartile, describing the central portion of the observed times. It does not have the same interpretation as a confidence interval. For the placebo-first group, the upper quartile is not reported, so the range is incomplete.
Why might a hazard ratio be reported?
For time-to-event outcomes, a hazard ratio can compare the event rates over follow-up between groups under a specified model. It uses information about when events occur and how long participants are observed. Its interpretation depends on the analysis and assumptions, including whether the relative event rate is adequately represented by the model over time. A hazard ratio is not the same as a ratio of medians. No hazard-ratio estimate or confidence interval for the primary endpoint is reported in the registry record.
A confidence interval expresses the statistical uncertainty around an estimate under the analysis assumptions. Its width reflects the precision of the estimate; it does not guarantee that the true value lies within the interval. Because the registry record does not give a confidence interval or another uncertainty measure for the primary contrast, the precision of that comparison cannot be judged from the medians alone. A p-value, if reported, would address compatibility with a specified null hypothesis under the model, but would not by itself describe effect size or practical importance. No primary-endpoint p-value is reported in the registry record.
How does the delayed-start design affect the contrast?
Randomization assigns participants to the initial treatment strategies, supporting a comparison of the groups as assigned when the analysis follows that assignment. Here, the strategies were immediate rilonacept versus placebo for 4 weeks followed by rilonacept. Once the delayed-start group begins active treatment, subsequent observations are no longer a comparison of active treatment against continuing placebo. The period and treatment strategy must therefore be kept in view when interpreting any outcome summary.
The registry identifies a parallel-group randomized design but does not report the randomization procedure, allocation ratio, or details of the statistical model. Those details matter because they describe how the randomized comparison was estimated and what assumptions underlie an inferential result. They cannot be inferred from the arm summaries.
How should the planning illustrations be understood?
Planning illustrations based on an observed effect are hypothetical calculations for future study planning, not results from the trial. The stated assumptions are a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. For time-to-event outcomes, the planning calculation concerns a total number of events; for other outcomes, it concerns participants per arm. These calculations are not observed power and do not show that the completed trial had a particular chance of detecting an effect. No planning values need to be treated as observed trial outcomes.
More generally, power is a design-stage probability calculated under assumed effect sizes, variability, and analysis choices. It is not a measure of whether a result is true after the data are observed. The registry record does not report the trial’s own sample-size justification or planned power assumptions. Accordingly, any planning illustration based on the observed effect should be read as an illustration under its stated assumptions, not as evidence about the trial’s design rationale or the reliability of its result.
What do the safety counts estimate?
The adverse-event record gives participants at risk and participants affected within listed study periods. These are counts of affected participants, not necessarily counts of all events, since one participant could experience more than one event. The record also separates serious adverse events from other adverse events. Comparing periods requires care because the group sizes and treatment histories differ across the periods. General statistical practice is to interpret such counts alongside exposure time, definitions, attribution, and the analysis plan; those details are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four secondary outcomes: JIA ACR50 and JIA ACR70 response, Pediatric Quality of Life Inventory, physical function measured with the Childhood Health Assessment Questionnaire, and presence of systemic features including fever and rash. It also reports six outcome measures overall. Multiple outcomes create the possibility of multiple statistical tests. If many tests are conducted, the chance of at least one apparently notable result can increase unless the analysis plan addresses multiplicity. The registry record does not report a multiplicity strategy, such as a hierarchy of outcomes or an adjustment procedure.
The registry record does not report analyses for the posted outcomes or a primary-endpoint inferential comparison. It does not state whether analyses were prespecified, which analysis populations were used, or whether participants were analyzed according to randomized assignment. The descriptions do not identify how missing outcome measurements, withdrawal, or incomplete follow-up were handled. These are unreported details, not evidence that missing data or analysis issues did not occur.
The primary outcome is defined with a corticosteroid-taper requirement for participants taking corticosteroids, but the registry does not describe how eligibility for that component was determined or how the endpoint was applied to participants not taking corticosteroids. It also does not report denominators for the primary time-to-response summaries beyond the listed group sizes. Without these details, the analysis population and the contribution of each participant to the endpoint cannot be reconstructed.
These omissions limit assessment of selective reporting, multiplicity, and the assumptions behind the primary result. The registry record does not report the protocol’s statistical analysis plan or interim analyses, so no conclusions about those procedures can be drawn.
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 |
|---|---|---|---|
| Rilonacept Week (0-4) | 1 | 36 | 2.8% |
| Placebo Week (0-4) | 1 | 35 | 2.9% |
| Rilonacept Week (4-24) | 3 | 35 | 8.6% |
| Placebo Week (4-24) | 1 | 33 | 3.0% |
| Long Term Extension 24 Weeks to 21 Months | 6 | 40 | 15.0% |
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 |
|---|---|
| Rilonacept Week (0-4) | 9 of 36 |
| Placebo Week (0-4) | 19 of 35 |
| Rilonacept Week (4-24) | 27 of 35 |
| Placebo Week (4-24) | 28 of 33 |
| Long Term Extension 24 Weeks to 21 Months | 28 of 40 |
Most frequent serious adverse event terms
| Event term | Organ system | Rilonacept Week (0-4) | Placebo Week (0-4) | Rilonacept Week (4-24) | Placebo Week (4-24) | Long Term Extension 24 Weeks to 21 Months |
|---|---|---|---|---|---|---|
| Juvenile Arthritis | Musculoskeletal and connective tissue disorders | 1 of 36 | 1 of 35 | 0 of 35 | 1 of 33 | 1 of 40 |
| Abnormal Liver Function Test | Gastrointestinal disorders | 0 of 36 | 0 of 35 | 1 of 35 | 0 of 33 | 0 of 40 |
| Pyrexia | Infections and infestations | 0 of 36 | 0 of 35 | 1 of 35 | 0 of 33 | 0 of 40 |
| Variccela | Infections and infestations | 0 of 36 | 0 of 35 | 1 of 35 | 0 of 33 | 0 of 40 |
| Viral uper respiratory tract infestion | Respiratory, thoracic and mediastinal disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
| Mental status Changes | Psychiatric disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
| Pericarditis | Cardiac disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
| Pharingitis,Streptoccocal | Respiratory, thoracic and mediastinal disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
| Gastroenteritis ,Salmonela | Gastrointestinal disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
| Histiocytosis,hematophagic | Blood and lymphatic system disorders | 0 of 36 | 0 of 35 | 0 of 35 | 0 of 33 | 1 of 40 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Rilonacept Week (0-4) | Placebo Week (0-4) | Rilonacept Week (4-24) | Placebo Week (4-24) | Long Term Extension 24 Weeks to 21 Months |
|---|---|---|---|---|---|---|
| Upper Respiratory tract infection | Respiratory, thoracic and mediastinal disorders | 0 of 36 | 1 of 35 | 5 of 35 | 9 of 33 | 2 of 40 |
| Headache | General disorders | 1 of 36 | 6 of 35 | 1 of 35 | 4 of 33 | 3 of 40 |
| injection site reaction | General disorders | 2 of 36 | 7 of 35 | 2 of 35 | 3 of 33 | 0 of 40 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 0 of 36 | 1 of 35 | 2 of 35 | 6 of 33 | 1 of 40 |
| Vomiting | Gastrointestinal disorders | 1 of 36 | 2 of 35 | 1 of 35 | 2 of 33 | 4 of 40 |
| Cough | Respiratory, thoracic and mediastinal disorders | 0 of 36 | 1 of 35 | 2 of 35 | 3 of 33 | 2 of 40 |
| Pharyngitis,Streptococcal | Respiratory, thoracic and mediastinal disorders | 0 of 36 | 0 of 35 | 2 of 35 | 2 of 33 | 4 of 40 |
| Pyrexia | Infections and infestations | 0 of 36 | 1 of 35 | 5 of 35 | 1 of 33 | 1 of 40 |
| Rash | Immune system disorders | 2 of 36 | 1 of 35 | 1 of 35 | 3 of 33 | 1 of 40 |
| Non Cardiac chest pain | General disorders | 0 of 36 | 3 of 35 | 1 of 35 | 4 of 33 | 0 of 40 |
Serious events with the highest arm-level rate: juvenile arthritis (3.0%), abnormal liver function test (2.9%), pyrexia (2.9%), variccela (2.9%), viral uper respiratory tract infestion (2.5%).
The serious adverse-event record reports participants affected within each listed period. During Weeks 0–4, the rilonacept group had 1 participant affected among 36 at risk; the placebo group had 1 among 35. During Weeks 4–24, 3 among 35 were affected in the rilonacept group and 1 among 33 in the placebo group. In the long-term extension from 24 weeks to 21 months, 6 among 40 were affected.
These figures are counts of participants with a serious adverse event, not a count of every event. A participant could experience more than one event, and the record does not provide event-level detail for each period. The long-term extension is a separate exposure period, not a randomized comparison between the original groups as described for the initial 4 weeks.
Risk sets and treatment histories vary across periods, so the counts should not be compared as if they came from one unchanged randomized contrast. The registry record does not report exposure-adjusted rates, attribution to study treatment, or a detailed event definition. Death results are not reported in the registry record. Serious-event counts alone do not establish causation or quantify comparative risk.
12. What the Result Does, and Does Not, Mean
The record documents a randomized comparison of two treatment-start strategies for children and young adults with SJIA: beginning rilonacept at Week 0 or receiving placebo for 4 weeks before beginning rilonacept. For the primary time-to-response outcome, the posted medians are 4.0 weeks for the immediate-start group and 8.0 weeks for the placebo-first group. The immediate-start group’s inter-quartile range is 2.0 to 10.0 weeks; the placebo-first group’s upper quartile is not reported.
These summaries do not provide a complete estimate of the randomized contrast. There is no reported hazard ratio, confidence interval, or p-value for the primary endpoint in the registry record. Consequently, the precision of the comparison and the extent to which the observed medians are compatible with different underlying effects cannot be assessed from the posted primary summaries. The medians should not be treated as proof of a causal difference.
The design also limits what the comparison represents. After 4 weeks, the placebo-first group began rilonacept. The trial therefore addresses early versus delayed initiation rather than continued rilonacept versus continued placebo throughout follow-up. Outcomes recorded after both groups began active treatment do not preserve the same treatment contrast as the initial period.
The safety results describe serious adverse events in changing risk sets and across different exposure periods. They are useful for understanding what the registry reports, but the record does not give treatment attribution or exposure-adjusted rates. The counts do not show that rilonacept caused an event or establish a comparative safety effect.
In short, the registry supports a description of the trial design, posted response-time summaries, and adverse-event counts. It does not support a precise inferential conclusion about the primary treatment contrast, a reconstruction of missing-data methods, or a conclusion about causality from the safety counts.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of a delayed-start randomized design. The groups differ in when active treatment begins: one starts at Week 0, while the other receives placebo for 4 weeks before starting rilonacept. That distinction clarifies the question the initial comparison can address and why later observations should not be interpreted as active treatment versus continuing placebo.
The primary outcome is time to a defined response rather than response status alone. Time-to-event outcomes can capture when a response occurs, but they require careful reporting of follow-up, censoring, and the analysis method. In this record, the posted medians offer a compact description of response timing, while the lack of a between-group estimate and uncertainty interval leaves the comparative inference incomplete.
The endpoint definition also illustrates how composite requirements shape interpretation. The response criterion includes no fever, and participants taking corticosteroids must meet a taper requirement. These conditions make the outcome more specific than a response score alone, but the registry does not explain how the steroid-related criterion was handled across the analysis population.
Finally, the safety record spans the initial period, a later period, and a long-term extension. Separate risk sets are essential to reading these counts: group membership and treatment exposure evolve over time. The record makes clear why adverse-event summaries should be interpreted with their time window and denominator, rather than pooled or compared without regard to design.
Taken together, the trial highlights a central statistical principle: descriptive results, design, and analysis details must be read together. A difference between reported medians can be described, but its precision and inferential meaning require an estimate and uncertainty measure that are not reported in the registry record.
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 statistical interpretation is that the registry reports group medians but no inferential estimate of the randomized contrast. A hazard ratio, confidence interval, and p-value are not reported for the primary endpoint. The upper quartile for the placebo-first group is also not reported, leaving its inter-quartile range incomplete.
The registry record does not describe censoring, the handling of participants without a recorded response, or the analysis population. It does not explain the statistical model, the randomization procedure, or the allocation ratio. These omissions prevent a reader from reconstructing the primary analysis or evaluating its assumptions.
The delayed-start structure means the placebo comparison applies to the initial 4-week period. After that, the placebo-first group receives rilonacept, so later outcomes do not represent a continuing randomized comparison of active treatment against placebo. The record does not provide enough detail to determine how later-period outcomes were analyzed relative to the original assignment.
Safety summaries are reported across periods with different risk sets and treatment histories. The registry does not report exposure-adjusted rates, treatment attribution, or whether each participant’s events were counted once or more than once in the event-level data. Death results are not reported in the registry record.
Eligibility criteria, detailed age limits, missing-data methods, multiplicity procedures, and the trial’s own sample-size justification are not reported in the registry record. These limitations restrict assessment of generalizability and statistical certainty; they do not indicate what unreported procedures or results might have been.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Effectiveness of Rilonacept for Treating Systemic Juvenile Idiopathic Arthritis in Children and Young Adults — NCT00534495.
- Registry record last updated 2015-12-11; status last verified 2015-11.
- Results first posted 2015-12-11.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed randomized, quadruple-masked, parallel-group Phase 2 trial sponsored by Montefiore Medical Center. Enrollment was 71. The study compared rilonacept beginning at Week 0 with placebo for 4 weeks followed by rilonacept in children and young adults with systemic juvenile idiopathic arthritis.
The primary outcome was time to a modified JIA ACR30 response requiring no fever, with a corticosteroid-taper requirement for participants taking corticosteroids, assessed at Week 12. The posted medians are 4.0 weeks for immediate rilonacept and 8.0 weeks for the placebo-first group. An inferential comparison and its uncertainty are not reported in the registry record.
The record lists four secondary outcomes and serious adverse-event counts across several periods. It does not report the primary analysis method, missing-data handling, multiplicity procedure, or treatment attribution for adverse events.