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 the Efficacy, Safety, and Tolerability of Rozanolixizumab in Adult Study Participants With Persistent or Chronic Primary Immune Thrombocytopenia (ITP) (NCT04224688), a randomized phase 3 study. The primary outcome is Percentage of Participants With Durable Clinically Meaningful Platelet Response of ≥50×10^9/L, for at Least 8 Out of 12 Weeks During the Last 12 Weeks.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04224688 |
| Phase | Phase 3 |
| Condition | Primary Immune Thrombocytopenia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 30 |
| Arms in the primary outcome | 2 |
| Lead sponsor | UCB Biopharma SRL |
| Results posted | Yes |
2. Clinical Question
Population
Adults with persistent or chronic primary immune thrombocytopenia (ITP) were eligible for the study. The randomized set consisted of enrolled participants who were randomized. The registry record reports 30 enrolled participants in total, with 20 in the rozanolixizumab arm and 10 in the placebo arm.
Intervention
Participants assigned to rozanolixizumab received fixed-unit doses across body-weight tiers at prespecified times during the treatment period. The registry record says doses could be adjusted based on platelet count values or medical needs. Specific dose amounts and the detailed adjustment rules are not reported in the registry record.
Comparator
The comparator was placebo, given at prespecified times during the treatment period. The study was randomized, double-blind, placebo-controlled, and parallel-group. The registry record describes the masking as quadruple but does not identify which roles were masked.
Primary question
The primary endpoint asked what percentage of participants had a durable clinically meaningful platelet response of at least 50×10^9/L for at least 8 out of 12 weeks during the last 12 weeks, from Week 13 to Week 25. The clinical question was whether the proportion meeting that response definition differed between participants assigned to rozanolixizumab and those assigned to placebo. Because the program was terminated, the registry record says that no formal analysis was carried out. The posted arm results are 5.0% for rozanolixizumab and 0.0% for placebo; the unadjusted recalculated risk difference is 0.05, with a confidence interval from -0.045 to 0.145.
3. Trial Design
This was a Phase 3, multicenter, randomized, double-blind, placebo-controlled, parallel-group study of rozanolixizumab in adults with persistent or chronic primary ITP. The registry record describes masking as quadruple. It does not say which study roles were masked, so the precise masking arrangement is not reported in the registry record.
The study began on 2020-06-03, and primary completion is recorded as 2022-04-25. Its status is terminated. Enrollment was 30 participants: 20 randomized to rozanolixizumab and 10 to placebo. The registry record says the program was terminated, but the reason for termination is not reported in the registry record. The planned allocation ratio and any reasons for the observed arm-size imbalance are not reported in the registry record.
Rozanolixizumab was given as fixed-unit doses across body-weight tiers at prespecified times during the treatment period, with doses adjusted based on platelet count values or medical needs. Participants in the placebo arm received placebo at prespecified times. The specific dose levels, treatment schedule, duration of exposure for each participant, and detailed dose-adjustment rules are not reported in the registry record.
The primary outcome covered the last 12 weeks of the treatment period, identified as Week 13 to Week 25. The registry record also lists secondary outcomes covering platelet responses, rescue therapy, a patient-assessment questionnaire, and adverse events. It lists 9 outcome measures in total and 8 posted secondary outcomes. The detailed protocol, statistical analysis plan, planned enrollment target, and sample-size justification are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Participant Flow refers to the Randomized Set.
Overall Study
| Stage | Placebo | Rozanolixizumab |
|---|---|---|
| STARTED | 10 | 20 |
| COMPLETED | 8 | 13 |
| NOT COMPLETED | 2 | 7 |
Reasons for not completing this period:
| Reason | Placebo | Rozanolixizumab |
|---|---|---|
| Withdrawal by Subject | 1 | 3 |
| Lack of Efficacy | 1 | 1 |
| Adverse event, not fatal | 0 | 2 |
| COVID-19 | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Randomized Set consisted of all enrolled study participants who were randomized. No formal analysis was carried out as the program was terminated.
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: Baseline Characteristics refer to Randomized Set which consisted of all enrolled study participants who were randomized.
| Characteristic | Unit | Placebo | Rozanolixizumab | Total |
|---|---|---|---|---|
| Participants analysed | 10 | 20 | 30 | |
| Age, Categorical: <=18 years | Participants | 0 | 1 | 1 |
| Age, Categorical: Between 18 and 65 years | Participants | 10 | 17 | 27 |
| Age, Categorical: >=65 years | Participants | 0 | 2 | 2 |
| Age, Continuous | years | 41.9 (SD 14.5) | 42.3 (SD 15.7) | 42.2 (SD 15.0) |
| Sex: Female, Male: Female | Participants | 6 | 13 | 19 |
| Sex: Female, Male: Male | Participants | 4 | 7 | 11 |
| Race/Ethnicity, Customized: Asian | Participants | 3 | 6 | 9 |
| Race/Ethnicity, Customized: White | Participants | 7 | 13 | 20 |
| Race/Ethnicity, Customized: Missing | Participants | 0 | 1 | 1 |
| Race/Ethnicity, Customized: Hispanic or Latino | Participants | 0 | 2 | 2 |
| Race/Ethnicity, Customized: Not Hispanic or Latino | Participants | 10 | 18 | 28 |
| Race/Ethnicity, Customized: Missing | Participants | 0 | 0 | 0 |
| Platelet count | cells*10^9/L | 14.10 (SD 7.77) | 14.65 (SD 8.18) | 14.46 (SD 7.91) |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Durable Clinically Meaningful Platelet Response of ≥50×10^9/L, for at Least 8 Out of 12 Weeks During the Last 12 Weeks, measured over During the last 12 weeks (Week 13 to Week 25).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint was the percentage of participants with a durable clinically meaningful platelet response of at least 50×10^9/L for at least 8 out of 12 weeks during the last 12 weeks of the study, from Week 13 to Week 25. It is a binary outcome at the participant level: each participant either met the specified response definition or did not. The endpoint then expresses the proportion meeting that definition in each randomized arm.
In general, requiring a response to persist over multiple weeks describes sustained response rather than a single platelet count at one visit. Such a definition can reduce the influence of a transient reading, while the specified threshold gives a common criterion for classifying response. The clinical rationale for selecting this endpoint beyond the description in the registry record is not reported in the registry record.
The posted results give 0.0% in the placebo arm and 5.0% in the rozanolixizumab arm. The registry record identifies the analysis population as the randomized set, consisting of enrolled participants who were randomized. It also explicitly says that no formal analysis was carried out because the program was terminated. The accompanying unadjusted recalculation is therefore descriptive evidence from a small randomized set, not a completed sponsor analysis of the primary endpoint.
7. Results Posted in the Registry
- Rozanolixizumab: 5.0% (1/20) versus 0.0% (0/10) on control; risk difference 5.0 percentage points (95% CI -4.6 to 14.6); unadjusted two-proportion z-test p = 0.472.
Risk difference: Rozanolixizumab
95% CI: -4.6 to 14.6 percentage points
Recalculated from the posted summary statistics
8. Secondary Efficacy Endpoints
The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.
| Secondary outcome | Type | Effect measure | Estimate (95% CI) | Planning size, 80% power |
|---|---|---|---|---|
| Percentage of Participants With Clinically Meaningful Platelet Response of ≥50×10^9/L by Day 8 | Binary Endpoint | Risk difference | +35.0 pts (6.3 to 63.7) | 25 per arm |
| Percentage of Participants With Response Defined as Platelet Count ≥30*10^9/L and at Least Doubling of Baseline, at Least 2 Separate Occasions at Two Adjacent Nominal Visits at Least 7 Days Apart, and Absence of Bleeding | Binary Endpoint | Risk difference | +10.0 pts (-15.6 to 35.6) | 199 per arm |
Percentage of Participants With Clinically Meaningful Platelet Response of ≥50×10^9/L by Day 8
- Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
- Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
- Result:
- Rozanolixizumab: 45.0% (9/20) versus 10.0% (1/10) on control; risk difference 35.0 percentage points (95% CI 6.3 to 63.7), risk ratio 4.50 (0.66–30.74); unadjusted two-proportion z-test p = 0.055.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rozanolixizumab and the control. The interval gives the range of effects that remain compatible with the data.
Percentage of Participants With Response Defined as Platelet Count ≥30*10^9/L and at Least Doubling of Baseline, at Least 2 Separate Occasions at Two Adjacent Nominal Visits at Least 7 Days Apart, and Absence of Bleeding
- Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
- Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
- Result:
- Rozanolixizumab: 20.0% (4/20) versus 10.0% (1/10) on control; risk difference 10.0 percentage points (95% CI -15.6 to 35.6), risk ratio 2.00 (0.26–15.62); unadjusted two-proportion z-test p = 0.488.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rozanolixizumab and the control. The interval gives the range of effects that remain compatible with the data.
The secondary outcomes cover response at an early time point, a response definition based on platelet count and absence of bleeding, cumulative response duration, time to response, rescue therapy, patient-reported symptoms, and adverse events. The available numerical response comparisons show point estimates favoring a higher response proportion in the rozanolixizumab arm, but their uncertainty is substantial. One interval includes zero, and the day 8 interval does not; the registry record does not report the interval or p-value methods needed to reconcile that distinction fully. These secondary findings do not replace the primary endpoint result, which also remains imprecise.
Some listed secondary outcomes have no posted numerical results in the record summarized by the registry. The registry record lists 8 secondary outcomes, while numerical arm comparisons are available for only two. Results for the remaining listed measures are not reported in the registry record. It is therefore not possible to infer an overall pattern across every planned or listed outcome, or to determine whether missing numerical results reflect noncollection, nonanalysis, or another reason.
In general, multiple outcomes create a multiplicity problem: when many hypotheses are examined, the chance of at least one apparently noteworthy result can increase. The registry record does not report a multiplicity adjustment or a prespecified hierarchy for secondary outcomes. Consequently, unadjusted secondary p-values should carry less weight than a prespecified, formally analyzed primary result. Here, the primary analysis itself was not formally carried out, which further limits the role of secondary comparisons as confirmatory evidence.
Secondary results can still describe the observed data and help identify questions for future studies, but they should not be used to override the primary endpoint's uncertainty. The small randomized set, the absence of a reported formal analysis, and the lack of reported multiplicity procedures all counsel against treating any single secondary comparison as decisive.
Secondary outcomes registered for this trial, for reference (only those above were recalculated):
- Cumulative Number of Weeks With Clinically Meaningful Platelet Response of ≥50×10^9/L Over the 24-week Treatment Period
- Time to First Clinically Meaningful Platelet Response (CMPR) of ≥50×10^9/L: Time From Starting Treatment to Achievement of First Response of ≥50×10^9/L
- Percentage of Participants With Clinically Meaningful Platelet Response of ≥50×10^9/L by Day 8
- Percentage of Participants With Response Defined as Platelet Count ≥30*10^9/L and at Least Doubling of Baseline, at Least 2 Separate Occasions at Two Adjacent Nominal Visits at Least 7 Days Apart, and Absence of Bleeding
- Time to First Rescue Therapy
- Change From Baseline to Week 25 in Primary Immune Thrombocytopenia Patient Assessment Questionnaire (ITP-PAQ) Symptoms Score
- Percentage of Participants With Treatment-emergent Adverse Events (TEAEs)
- Percentage of Participants With TEAEs Leading to Withdrawal of Investigational Medicinal Product (ie, Study Discontinuation)
9. Statistical Interpretation
For the primary endpoint, the posted response percentages were 0.0% in the placebo arm and 5.0% in the rozanolixizumab arm. The unadjusted recalculated risk difference was 0.05, with a confidence interval from -0.045 to 0.145 and an unadjusted p-value of 0.472. The point estimate favors a higher response proportion in the rozanolixizumab arm, but the interval spans zero and also allows values on either side of zero. The estimate is therefore imprecise and does not establish a clear difference between arms.
These results need to be read alongside the registry statement that no formal analysis was carried out because the program was terminated. The listed comparison is a simple unadjusted recalculation from the posted summary statistics, not a substitute for a sponsor analysis that was not performed. The registry record does not report a formal analysis method, adjustment strategy, or prespecified inferential test for this endpoint.
The small randomized set matters for interpretation: the primary result is based on 10 placebo participants and 20 rozanolixizumab participants. With few participants, a small change in the number meeting the response definition could materially affect the estimated proportions. The confidence interval conveys this uncertainty; it should not be read as evidence that the true effect is exactly at the point estimate, nor as proof that there is no difference.
The secondary results describe other response definitions and time points, but they do not resolve the uncertainty in the primary endpoint. They are also unadjusted and should be treated as exploratory in the absence of a reported multiplicity plan. Overall, the posted primary data show a higher observed response percentage in the rozanolixizumab arm, while the uncertainty is substantial and the registry record reports no formal analysis. This supports a cautious description of the observed data, not a definitive conclusion about comparative efficacy.
10. Statistical Methods Explained
What does a risk difference describe?
In general, a risk difference compares the proportions experiencing an outcome in two groups by subtracting one proportion from the other. It is expressed on the proportion scale: zero represents equal observed proportions, positive values indicate a larger proportion in the intervention group, and negative values indicate a smaller proportion in that group, when the comparator is the reference. The primary recalculated risk difference is 0.05. It is an unadjusted comparison, based on the posted arm-level summaries, rather than an estimate adjusted for participant characteristics or other factors.
The registry record gives the primary arm percentages as 0.0% for placebo and 5.0% for rozanolixizumab. It also gives the counts meeting the endpoint as 0 of 10 and 1 of 20, respectively. These small counts help explain why the estimate is uncertain: a single participant meeting the endpoint has a noticeable influence when the groups are small. No model-based adjustment or covariate adjustment is reported in the registry record.
What does the confidence interval add?
In general, a confidence interval gives a range of values compatible with the data under the method used to calculate it. It communicates statistical uncertainty around an estimate; it is not a range that guarantees where the true effect lies, and it does not show the probability that a particular effect is true. The primary interval extends from -0.045 to 0.145. Because it includes zero, the posted interval is compatible with no difference as well as differences in either direction. The interval is broad relative to the point estimate, consistent with limited precision in this small set of participants.
The method used to calculate the confidence interval is not reported in the registry record. The same is true of the method used for the unadjusted p-value. A p-value describes how unusual the observed data, or more extreme data, would be under a specified null hypothesis and analysis method. It is not the probability that the null hypothesis is true. The primary unadjusted p-value is 0.472, but without the sponsor's formal analysis and the method details, it should be interpreted only as part of the simple recalculation presented with the posted summaries.
Why distinguish posted results from recalculations?
The registry record states that no formal analysis was carried out because the program was terminated. The risk difference, interval, and unadjusted p-value reported with the primary summary are therefore recalculated, unadjusted comparisons. They do not establish what a prespecified sponsor analysis would have concluded, and no such analysis is reported in the registry record. There is no discrepancy flagged between the posted summaries and recalculation, but that does not change the distinction between descriptive recalculation and a formal trial analysis.
For the binary outcomes, a participant is classified as meeting or not meeting the endpoint, and the arm-level value is a percentage of participants. This differs from outcomes measured on a continuous scale, where each participant contributes a numerical amount such as a change score. In general, binary outcomes can be sensitive to the exact response threshold and time window. Here, the primary endpoint combines a platelet threshold with a requirement for repeated response during a specified period. That definition should be kept in mind when comparing it with the secondary outcomes, which use other thresholds, periods, or criteria.
How should the planning illustrations be read?
In general, sample-size planning asks how many participants would be needed under stated assumptions to detect an effect with a chosen power and significance level. The planning illustrations associated with the secondary results are based on the observed effect, not on the trial's own design. They assume a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation; the assumed effect is a stated fraction of the observed effect. These are planning illustrations only, not observed power and not evidence that the terminated trial was designed around those assumptions.
The registry record does not report the trial's own sample-size justification, target enrollment, or original design assumptions. The planning illustrations therefore cannot be used to infer the planned size of this study or why it enrolled 30 participants. In general, using an observed effect for planning can be unstable, especially when the observed groups are small and the estimate is imprecise. The illustrations are best treated as hypothetical calculations under their stated assumptions, rather than as a forecast or a retrospective assessment of whether the study was adequately powered.
11. Confidence Intervals and Precision
The primary unadjusted risk difference is 0.05, with a confidence interval from -0.045 to 0.145. The interval includes zero, so the data are compatible with no difference in the underlying response proportions under the calculation used. It also includes values on either side of zero. The point estimate alone does not capture that uncertainty; the interval is essential to judging how precisely the comparison was estimated.
In general, a confidence interval is a measure of uncertainty around an estimate, conditional on the statistical method and assumptions used. A narrow interval would indicate greater precision, while a wide interval would indicate that a broader range of effects remains compatible with the data. The method used for this interval is not reported in the registry record. The small arm sizes—10 participants on placebo and 20 on rozanolixizumab—and the low number meeting the primary endpoint contribute to the limited information available, although the exact contribution of each factor is not separately quantified in the registry record.
The unadjusted p-value for the primary recalculation is 0.472. In general, a p-value is not a measure of effect size or precision and does not tell whether a treatment effect is clinically important. It should be interpreted with the estimated effect, interval, endpoint definition, and analysis context. Here, the registry record says no formal analysis was carried out, so the recalculated p-value cannot be treated as the result of a sponsor's prespecified primary analysis.
For the secondary results, confidence intervals are also broad. The day 8 risk-difference interval is 0.064 to 0.637, while the interval for the other posted secondary response comparison extends from -0.155 to 0.355. The registry record does not report the methods used to calculate these intervals. Precision is therefore limited both by the small number of participants and by missing information about the inferential methods.
12. Multiplicity, Missing Data and Analysis Populations
The registry record identifies the randomized set as the analysis population for the primary outcome: enrolled participants who were randomized. It does not describe how missing endpoint assessments were handled, whether participants with incomplete follow-up were counted as responders or nonresponders, or whether any imputation procedure was used. These details are not reported in the registry record. The record also does not specify the number of participants with missing primary endpoint data, so the completeness of endpoint ascertainment cannot be assessed from the posted information.
The study lists several secondary outcomes, including multiple platelet-response measures, time-to-event outcomes, a patient-assessment questionnaire, and adverse-event outcomes. The registry record does not report a statistical plan for controlling multiplicity, such as an ordering of hypotheses or an adjustment to account for multiple comparisons. Without that information, secondary inferential results should be treated as exploratory rather than as independent confirmatory tests.
The record explicitly states that no formal analysis was carried out because the program was terminated. It does not report a formal analysis population beyond the randomized-set description, a protocol-defined estimand, a model specification, covariate adjustments, or sensitivity analyses. It also does not report whether an interim analysis was planned or performed. These aspects cannot be reconstructed from the posted summaries and should not be inferred.
In general, missing-data choices can affect a binary endpoint, particularly when the event is uncommon and the number of participants is small. Different assumptions about participants without an observed endpoint can lead to different estimates. Likewise, multiplicity procedures can affect how secondary p-values are interpreted. Since the relevant details are not reported in the registry record, the posted recalculations remain unadjusted descriptions of the available arm summaries rather than a substitute for an analysis plan.
13. 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 |
|---|---|---|---|
| Placebo | 1 | 10 | 10.0% |
| Rozanolixizumab | 5 | 20 | 25.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Placebo | 0 of 10 |
| Rozanolixizumab | 0 of 20 |
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 |
|---|---|
| Placebo | 6 of 10 |
| Rozanolixizumab | 18 of 20 |
Most frequent serious adverse event terms
| Event term | Organ system | Placebo | Rozanolixizumab |
|---|---|---|---|
| Platelet count decreased | Investigations | 1 of 10 | 1 of 20 |
| Thrombocytopenia | Blood and lymphatic system disorders | 1 of 10 | 0 of 20 |
| Vomiting | Gastrointestinal disorders | 0 of 10 | 1 of 20 |
| Pneumonia viral | Infections and infestations | 0 of 10 | 1 of 20 |
| Head injury | Injury, poisoning and procedural complications | 0 of 10 | 1 of 20 |
| Limb injury | Injury, poisoning and procedural complications | 0 of 10 | 1 of 20 |
| Skin injury | Injury, poisoning and procedural complications | 0 of 10 | 1 of 20 |
| Headache | Nervous system disorders | 0 of 10 | 1 of 20 |
| Dizziness | Nervous system disorders | 0 of 10 | 1 of 20 |
| Urticaria | Skin and subcutaneous tissue disorders | 0 of 10 | 1 of 20 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Placebo | Rozanolixizumab |
|---|---|---|---|
| Headache | Nervous system disorders | 2 of 10 | 12 of 20 |
| Pyrexia | General disorders | 0 of 10 | 6 of 20 |
| Nausea | Gastrointestinal disorders | 0 of 10 | 3 of 20 |
| Upper respiratory tract infection | Infections and infestations | 1 of 10 | 2 of 20 |
| Anaemia | Blood and lymphatic system disorders | 0 of 10 | 2 of 20 |
| Diarrhoea | Gastrointestinal disorders | 0 of 10 | 2 of 20 |
| Gingival bleeding | Gastrointestinal disorders | 0 of 10 | 2 of 20 |
| Abdominal pain | Gastrointestinal disorders | 1 of 10 | 1 of 20 |
| Constipation | Gastrointestinal disorders | 1 of 10 | 1 of 20 |
| Fatigue | General disorders | 0 of 10 | 2 of 20 |
Serious events with the highest arm-level rate: thrombocytopenia (10.0%), platelet count decreased (10.0%), vomiting (5.0%), pneumonia viral (5.0%), head injury (5.0%).
The posted serious adverse-event figures show 1 of 10 participants in the placebo arm and 5 of 20 in the rozanolixizumab arm affected by a serious adverse event. The record reports zero deaths in both arms. For other adverse events, the figures are 6 of 10 in the placebo arm and 18 of 20 in the rozanolixizumab arm. These are descriptive counts from small groups; they do not, by themselves, establish that an event was caused by study treatment or support a reliable comparison of safety between arms.
The registry record lists thrombocytopenia and platelet count decreased at 10.0% each, and vomiting, pneumonia viral, head injury, and limb injury at 5.0% each among the top serious adverse-event terms. The arm attribution and event counts for each listed term are not reported in the registry record. It is therefore not appropriate to assign those terms to one arm or infer comparative risks from the percentages alone.
In general, adverse-event counts describe events observed during a study, while attribution and comparative safety interpretation require additional information, including definitions, exposure, timing, and clinical assessment. Those details are not reported in the registry record. The small randomized set also limits the ability to characterize uncommon events.
14. What the Result Does, and Does Not, Mean
The primary data show that 5.0% of participants in the rozanolixizumab arm and 0.0% in the placebo arm met the durable response definition. The unadjusted recalculated risk difference is 0.05, with an interval from -0.045 to 0.145. This describes the observed comparison and its uncertainty; it is not a definitive estimate from a formal sponsor analysis. The registry record specifically says that no formal analysis was carried out because the program was terminated.
The result does not establish that the arms differ, because the interval includes zero and the estimate is imprecise. It also does not establish that the arms are equivalent, or that there is no possible difference. A nonsignificant or uncertain comparison is not proof of no effect. The small group sizes and low number of primary endpoint responders leave substantial uncertainty around the observed proportions.
The result also does not answer every question about platelet response or treatment experience. The primary definition requires a threshold response sustained for a specified portion of the final 12-week period. Other response definitions and time windows may produce different summaries. The registry record lists additional outcomes, but numerical findings for most of them are not reported in the registry record. The observed primary result should not be generalized to unreported outcomes or populations beyond the adults with persistent or chronic primary ITP described for this trial.
Nor do these data establish a causal safety conclusion. Adverse-event counts are descriptive, and the registry record does not provide detailed event attribution or the full context needed for a comparative safety analysis. Overall, the posted results are useful as a record of what was observed in this small randomized study, but they do not support a conclusive efficacy or safety claim.
15. Why This Trial Matters Statistically
This study illustrates why the status and analysis context of a trial matter as much as its point estimate. The registry record describes a randomized, placebo-controlled Phase 3 study, but also states that the program was terminated and no formal analysis was carried out. The posted arm summaries can be described, and simple unadjusted comparisons can be calculated from them, but those comparisons are not equivalent to a completed prespecified analysis.
The primary endpoint is a sustained binary response, which makes the event definition and its time window central to interpretation. A reader needs to distinguish a response observed at one time from a response meeting the full durability criterion. The distinction also helps explain why the primary result should not be conflated with other platelet-response outcomes listed in the registry.
The study's small randomized set highlights the importance of precision. A percentage can appear visually different between arms while still being compatible with a broad range of underlying differences. The interval for the primary comparison includes zero and extends in both directions, so the point estimate cannot carry the interpretation by itself.
Finally, the record demonstrates the limits of secondary findings when multiplicity procedures and a formal analysis plan are not reported. Secondary outcomes may be informative descriptively, but unadjusted comparisons should not be treated as definitive tests. The trial matters statistically because it shows how estimates, uncertainty, analysis status, and missing methodological details must be considered together before drawing conclusions from posted clinical-trial results.
16. 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.
- Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.
The most important trial-specific limitation is that the registry record states the program was terminated and no formal analysis was carried out. It does not give the reason for termination, so no explanation should be inferred. With 30 randomized participants, including 10 on placebo and 20 on rozanolixizumab, estimates are based on small groups and the primary endpoint was met by only a small number of participants. This limits precision and makes the observed percentages sensitive to individual outcomes.
There is no sponsor analysis reported for the primary endpoint, and the recalculated comparison is unadjusted. The registry record does not provide the method for calculating intervals or p-values, details of missing-data handling, a multiplicity plan, or sensitivity analyses. These omissions limit assessment of how robust the reported comparisons are and how they relate to any original protocol-defined analysis.
The registry record lists a broad set of secondary outcomes, but only some have numerical results posted. The reason that numerical results are absent for other listed outcomes is not reported in the registry record. This restricts the ability to assess the full pattern of response, time-to-event, patient-reported, and safety outcomes.
The adverse-event summaries are also limited: arm-level counts are available for serious and other adverse events, but the listed serious terms are not attributed to arms in the available record. Exposure duration and detailed event context are not reported. Finally, details of randomization procedures, allocation concealment, masking roles, dose levels, and the trial's planned sample-size justification are not reported in the registry record. These limitations constrain interpretation without determining the reason for them.
17. Related Tutorials
18. Related Statistical Calculators
19. Sources
- ClinicalTrials.gov: A Study to Assess the Efficacy, Safety, and Tolerability of Rozanolixizumab in Adult Study Participants With Persistent or Chronic Primary Immune Thrombocytopenia (ITP) — NCT04224688.
- Registry record last updated 2023-08-08; status last verified 2023-08.
- Results first posted 2023-08-08.
- 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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20. Record Summary
NCT04224688 is a randomized, quadruple-masked, parallel-group, placebo-controlled Phase 3 study of rozanolixizumab in adults with persistent or chronic primary ITP. The registry record reports 30 randomized participants: 20 assigned to rozanolixizumab and 10 to placebo. The primary endpoint was a durable clinically meaningful platelet response of at least 50×10^9/L for at least 8 out of 12 weeks during the last 12 weeks, from Week 13 to Week 25.
Posted primary response percentages were 5.0% for rozanolixizumab and 0.0% for placebo. The unadjusted recalculated risk difference was 0.05, with a confidence interval from -0.045 to 0.145 and p = 0.472. The record says the study program was terminated and no formal analysis was carried out. The reason for termination and several analysis details are not reported in the registry record, so the posted comparison should be read as descriptive and uncertain.