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 IdeS in Asymptomatic Antibody-Mediated Thrombotic Thrombocytopenic Purpura (TTP) Patients (NCT02854059), a non-randomized phase 2 study. The primary outcome is Safety and Tolerability as Measured by Type, Frequency and Intensity of Adverse Events.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02854059 |
| Phase | Phase 2 |
| Condition | Purpura, Thrombotic Thrombocytopenic |
| Allocation | Non-Randomized |
| Design model | Sequential |
| Masking | None (open label) |
| Enrollment | 2 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Hansa Biopharma AB |
| Results posted | Yes |
2. Clinical Question
Population
Participants were patients with asymptomatic antibody-mediated thrombotic thrombocytopenic purpura (TTP) and low ADAMTS13 activity. The registry reports that 2 participants enrolled. Further details about eligibility criteria and the characteristics of the enrolled participants are not reported in the registry record.
Intervention
The study evaluated a single intravenous dose of IdeS. The planned dose levels were IdeS (0.25 mg/kg) and IdeS (0.50 mg/kg), each described as a 30 minutes i.v. infusion. The registry reports enrollment in the 0.25 mg/kg group; it reports no participants in the 0.50 mg/kg group.
Comparator
There was no randomized control group. The study was non-randomized and sequential, so the dose groups were not designed as like-for-like comparator arms. Because no participants were enrolled in the 0.50 mg/kg group, the record also does not provide observed outcomes for that planned dose level.
Primary question
The stated main purpose was to evaluate safety and tolerability after IdeS, with the primary outcome describing the type, frequency, and intensity of adverse events from dosing until the end of follow-up on day 64. The registry record says the study ended early because of a non-favourable risk-benefit profile in the first 2 participants.
3. Trial Design
This was a Phase II pilot study listed as non-randomized, unmasked, and sequential. It was designed to examine IdeS in asymptomatic antibody-mediated TTP patients with low ADAMTS13 activity. The registry lists 2 participants enrolled, a study start of 2016-09, primary completion in 2017-01, and a status of terminated.
The intervention descriptions specify a single 30 minutes i.v. infusion of IdeS (0.25 mg/kg) or IdeS (0.50 mg/kg). The record describes a planned sequence in which safety and efficacy would be evaluated in 3 patients receiving 0.25 mg/kg, followed by the potential to increase the dose to 0.5 mg/kg for the remaining 3 patients. That plan was not completed: the record lists 2 participants in the 0.25 mg/kg group and none in the 0.50 mg/kg group.
The study did not use random allocation or masking. Consequently, these dose groups should not be interpreted as randomized treatment and control groups. The sequential plan is relevant to understanding the intended dose progression, but the available enrollment does not support a comparison between the dose levels.
The sponsor reports that the study was terminated prematurely because of a non-favourable risk-benefit profile in the first 2 patients and that it would no longer pursue the indication. The protocol analyses were not performed. The planned sample-size justification and any details about interim analyses or other statistical procedures are not reported in the registry record. The record names secondary outcomes involving ADAMTS13 activity and antibodies, IgG, F(ab')2 fragments, IdeS concentration and immunogenicity, but it does not report completed analyses of those outcomes.
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 | Treatment IdeS (0.25 mg/kg) | IdeS (0.50 mg/kg) |
|---|---|---|
| STARTED | 2 | 0 |
| COMPLETED | 2 | 0 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Because of the premature termination of the study due to the non-favourable risk-benefit profile in the first 2 patients and since the sponsor will no longer pursue the indication, the analyses as described in the protocol were not performed. Instead, data collected for the 2 enrolled subjects were listed and/or presented graphically.
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: After review of the initial results from the study that demonstrated a non-favourable risk-benefit profile in the first 2 patients who received single i.v. infusion of IdeS (0.25 mg/kg), the study was prematurely discontinued. The potential dose escalation to i.v. infusion of IdeS (0.5 mg/kg) did not occur.
| Characteristic | Unit | Treatment IdeS (0.25 mg/kg) | Treatment IdeS (0.50 mg/kg) | Total |
|---|---|---|---|---|
| Participants analysed | 2 | 0 | 2 | |
| Age, Categorical: <=18 years | Participants | 0 | — | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 2 | — | 2 |
| Age, Categorical: >=65 years | Participants | 0 | — | 0 |
| Sex: Female, Male: Female | Participants | 1 | — | 1 |
| Sex: Female, Male: Male | Participants | 1 | — | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | — | 0 |
| Race (NIH/OMB): Asian | Participants | 0 | — | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | — | 0 |
| Race (NIH/OMB): Black or African American | Participants | 1 | — | 1 |
| Race (NIH/OMB): White | Participants | 1 | — | 1 |
| Race (NIH/OMB): More than one race | Participants | 0 | — | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | — | 0 |
| Region of Enrollment: United Kingdom | participants | 2 | — | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Safety and Tolerability as Measured by Type, Frequency and Intensity of Adverse Events, measured over From dosing until end of follow up on day 64.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Adverse Events |
| Endpoint classification | not reduced to a single comparison |
The primary outcome was safety and tolerability, measured by the type, frequency, and intensity of adverse events. Its timeframe ran from dosing until the end of follow-up on day 64. The registry describes adverse events as identified through spontaneous patient reports, responses to open questions from study personnel, or observation. The outcome therefore concerns reported or observed events during follow-up, rather than a single laboratory measurement or a comparative estimate of treatment effect.
The registry defines a treatment-emergent adverse event (TEAE) as an event occurring after administration of the investigational medicinal product and within the residual drug effect period, defined as 30 days after administration. It also states that adverse events reported in ClinicalTrials.gov include TEAEs and post-treatment events: all adverse events occurring after IdeS administration until the end of the study. The endpoint description directs readers to the adverse event information for details on reported events.
Safety and tolerability are relevant outcomes in a pilot study because they characterize the adverse events observed after exposure. They do not, by themselves, establish whether an event was caused by treatment. In this record, the small enrollment and early termination make the safety observations descriptive and limited to the enrolled participants. The protocol analyses were not performed, so the record does not provide a completed statistical assessment of the primary outcome as originally planned.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes an early-terminated pilot with 2 enrolled participants, both in the IdeS (0.25 mg/kg) group. No participants are listed in the IdeS (0.50 mg/kg) group. The reported information therefore concerns a very small exposed group at one dose level; it cannot establish how outcomes would compare across dose levels or against an untreated or control group.
The registry lists the study as terminated and states that the sponsor ended it prematurely because of a non-favourable risk-benefit profile in the first 2 patients. It also says the sponsor would no longer pursue the indication. This is an important account of why the study stopped, but the registry record does not provide a completed protocol analysis that would quantify a treatment effect or characterize the uncertainty around an effect estimate.
For safety, the adverse event data are best read as observations in the participants who enrolled, not as estimates that can be generalized reliably to a broader patient population. The record lists serious adverse events in the 0.25 mg/kg group and names serum sickness and thrombotic thrombocytopenic purpura among the leading serious event terms. These observations merit attention in understanding the study’s termination, but the registry information does not establish causation. In particular, the presence of an event after treatment does not alone show that IdeS caused it.
The outcome list includes measures of ADAMTS13 activity and antibody levels, return of decreased ADAMTS13 activity to normal levels, IgG, F(ab')2 fragments, IdeS pharmacokinetics, and anti-drug antibodies. These are stated outcomes, not evidence that the analyses were completed or that a particular change occurred. The record explicitly says the analyses described in the protocol were not performed; specific analysis results for these measures are not reported in the registry record.
Statistical precision is necessarily limited when observations come from so few participants. Even when an observed event proportion is reported, it can vary substantially with the experience of an individual participant and should not be mistaken for a stable estimate of risk. No adjusted or comparative analysis is reported. The listed groups are not randomized comparators, and the 0.50 mg/kg group has no enrolled participants.
Any planning illustrations based on an observed effect should be understood as hypothetical sample-size calculations rather than evidence about the study’s actual design or power. The record states that the protocol analyses were not performed. Thus, the most defensible reading is descriptive: the registry documents what was planned, the limited enrollment, the stated reason for early termination, and the adverse-event information it reports. It does not support a definitive efficacy conclusion or a precise estimate of safety for the wider population.
9. Statistical Methods Explained
Statistical methods help distinguish what an investigation set out to learn from what its recorded data can establish. In this study, the stated primary purpose was safety and tolerability. The planned design was sequential and non-randomized, and the registry says the protocol analyses were not performed. That means descriptions of general statistical methods can clarify how such data are commonly interpreted, but they should not be mistaken for methods that were actually applied in this trial.
What does a non-randomized, sequential design imply?
In a randomized comparison, allocation is intended to make treatment groups comparable with respect to both measured and unmeasured characteristics, on average. This study was not randomized. Its planned dose progression also meant that participants were not assigned concurrently as equivalent comparison groups. Differences between groups, if groups had both enrolled, could reflect the sequence or characteristics of participants as well as dose. Here, the registry lists participants only in the 0.25 mg/kg group, so it supplies no observed 0.50 mg/kg group for comparison.
Masking was listed as none. In general, masking can reduce the possibility that awareness of the assigned intervention affects how outcomes are assessed or reported. For adverse events, many findings are based on symptoms, questions, or observation, as described in this record. Without masking, knowledge of treatment may be relevant to assessment, although the registry does not describe whether or how that possibility was addressed.
How should adverse-event counts be interpreted?
Adverse-event summaries describe the events recorded during a specified observation period. A count of participants with an event is different from a count of all event occurrences: one participant can experience more than one event, and one event type can occur in more than one participant. The record’s primary outcome refers to type, frequency, and intensity, while its description says events could be identified through spontaneous reporting, open questions, or observation. Interpretation therefore depends on the event definitions, follow-up, and completeness of ascertainment.
The record distinguishes TEAEs from the broader set of adverse events reported after IdeS until study end. A TEAE is defined by its timing after administration and the stated residual drug effect period. This definition identifies an observation window; it does not, by itself, establish that an event was caused by treatment. Attribution, event severity, and seriousness are distinct concepts. A serious event is classified according to seriousness criteria, while intensity describes how severe the event was. The available primary outcome description refers to both intensity and event type, but detailed analysis procedures are not reported in the registry record.
What would an estimate and confidence interval normally convey?
In general, an estimate summarizes the observed data, while a confidence interval expresses the statistical uncertainty associated with that estimate under a specified method and assumptions. A narrow interval indicates greater precision than a wide interval, but an interval cannot remedy weaknesses such as an absent comparator, incomplete outcome data, or a highly selected participant group. With limited observations, uncertainty is especially important. The registry does not report a completed protocol analysis or confidence intervals for a treatment effect.
A p-value, when used, describes how compatible the observed data are with a specified statistical model under a null hypothesis. It is not the probability that a treatment works or that the null hypothesis is true. Statistical significance is also not the same as clinical importance. No analysis results or p-values are reported for the study’s protocol analyses; the record states those analyses were not performed.
Why can over-dispersion matter?
In general, over-dispersion occurs when count data vary more than a statistical model assumes. If it is ignored, uncertainty can be understated and confidence intervals can be too narrow. Methods for count outcomes may account for this extra variation, but the appropriate approach depends on the design, the distribution of events, and the amount of available information. The registry does not report an analysis of over-dispersion or a statistical model for the primary outcome. With the limited enrollment recorded, the data also offer little basis for estimating complex features of event variation.
What can sample-size planning illustrations tell a reader?
In general, a sample-size calculation describes how much information might be needed to detect a prespecified effect under specified assumptions. It is a planning exercise, not a result about the participants who actually enrolled. The record’s planning illustration is described as based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It specifies that the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the illustration concerns a total number of events using the Schoenfeld approach; other illustrations refer to participants per arm.
Those assumptions do not make the study randomized, change the actual enrollment, or show that the trial had a particular observed power. The record does not report the protocol’s sample-size justification, and the planned analyses were not performed. Sample-size illustrations should therefore be read only as hypothetical planning information, not as evidence that the study was adequately powered or that an effect was confirmed.
What does the record allow statistically?
The registry supports a descriptive account of the study plan, enrollment, termination, stated primary outcome, and recorded adverse-event summaries. It does not provide the protocol analyses or a comparative estimate of treatment effect. The listed secondary outcomes identify questions that the study intended to address, but outcome names alone do not establish findings. Any interpretation should keep these distinctions clear: planned versus completed analyses, event timing versus causation, and observed descriptions versus population-level estimates.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity arises when an investigation evaluates several outcomes, time points, or statistical comparisons. In general, the more analyses undertaken, the greater the chance that at least one result may appear notable by chance alone. A statistical plan may address this through a prespecified hierarchy, adjustment, or a clearly exploratory interpretation. The registry names multiple secondary outcomes, including ADAMTS13 activity and antibody levels, IgG, F(ab')2 fragments, IdeS pharmacokinetics, and anti-drug antibodies. It does not report a multiplicity strategy. More importantly, the registry says the analyses described in the protocol were not performed.
The registry lists 9 outcome measures and 0 analyses. That distinction matters: an outcome measure can be specified without a completed analysis result. The record does not give analysis populations, a missing-data method, or details about how participants with incomplete follow-up would have been handled. Those items are not reported in the registry record.
Missingness can affect interpretation when outcomes are unavailable for some participants. In general, the reasons data are missing and whether missingness is related to a participant’s health or outcome can influence the validity of an estimate. Early termination can also limit the amount and duration of collected information. The registry states that follow-up for the primary outcome was intended to continue until day 64, but the completeness of follow-up and the handling of any missing observations are not reported in the registry record.
Because the planned analyses were not performed, there is no basis in the record for claiming that a prespecified primary analysis population or multiplicity procedure was used. The outcome list should be read as a description of what was planned to be assessed, not as a set of completed statistical tests.
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 |
|---|---|---|---|
| Treatment IdeS (0.25 mg/kg) | 2 | 2 | 100.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment IdeS (0.25 mg/kg) | 0 of 2 |
| Treatment IdeS (0.50 mg/kg) | 0 of 0 |
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 |
|---|---|
| Treatment IdeS (0.25 mg/kg) | 2 of 2 |
| Treatment IdeS (0.50 mg/kg) | 0 of 0 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment IdeS (0.25 mg/kg) | Treatment IdeS (0.50 mg/kg) |
|---|---|---|---|
| Serum sickness | Immune system disorders | 2 of 2 | n/a of 0 |
| Thrombotic thrombocytopenic purpura | Blood and lymphatic system disorders | 1 of 2 | n/a of 0 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment IdeS (0.25 mg/kg) | Treatment IdeS (0.50 mg/kg) |
|---|---|---|---|
| Arthralgia | Musculoskeletal and connective tissue disorders | 2 of 2 | n/a of 0 |
| Rash | Skin and subcutaneous tissue disorders | 2 of 2 | n/a of 0 |
| Dry mouth | Gastrointestinal disorders | 1 of 2 | n/a of 0 |
| Pyrexia | General disorders | 1 of 2 | n/a of 0 |
| Headache | Nervous system disorders | 1 of 2 | n/a of 0 |
| Tachycardia | Cardiac disorders | 1 of 2 | n/a of 0 |
Serious events with the highest arm-level rate: serum sickness (100.0%), thrombotic thrombocytopenic purpura (50.0%).
The registry reports adverse-event group information for IdeS (0.25 mg/kg): 2 participants were at risk for serious adverse events and 2 were affected. It lists no participants at risk or affected in the IdeS (0.50 mg/kg) group. Deaths are reported as 0 in both groups. These are registry summaries for the enrolled study participants, not estimates of event frequency in a broader population.
The leading serious event terms listed are serum sickness (100.0%) and thrombotic thrombocytopenic purpura (50.0%). These percentages should be read in the context of the very small exposed group and the registry’s event reporting. They do not establish that IdeS caused the events. The record separately states that the study was terminated early because of a non-favourable risk-benefit profile in the first 2 patients; it does not identify a causal attribution for each listed event.
Seriousness and intensity are not interchangeable. The primary outcome description refers to event type, frequency, and intensity, while the serious-event summary identifies serious events. The record’s adverse-event definition includes events reported after treatment through the end of the study, and it distinguishes these from TEAEs by the stated residual drug effect period. The summary should therefore be understood as descriptive safety information within the registry’s specified reporting framework.
12. What the Result Does, and Does Not, Mean
The record establishes that a Phase II pilot study was intended to evaluate safety and tolerability after a single dose of IdeS in asymptomatic antibody-mediated TTP patients with low ADAMTS13 activity. It records 2 participants enrolled, both in the IdeS (0.25 mg/kg) group, and no participants in the IdeS (0.50 mg/kg) group. It also records that the study was terminated early because of a non-favourable risk-benefit profile in the first 2 patients.
These registry entries do not establish a treatment effect. There was no randomized comparator, and no participants received the planned higher dose. The registry says the protocol analyses were not performed, so the listed secondary outcomes do not constitute evidence of efficacy, pharmacodynamic change, or pharmacokinetic findings. Specific results for those measures are not reported in the registry record.
The adverse-event summaries describe what was recorded among the participants who enrolled. They do not provide a reliable estimate of how often the same events would occur in a larger or different population, nor do they prove that treatment caused an event. A temporal relationship after dosing is not sufficient by itself to establish causation. The sponsor’s stated reason for termination is important context, but it is not a substitute for a completed statistical analysis.
Statistical power is a design concept describing the chance that a study will detect a specified effect under its assumptions. It is not a property that can be inferred simply from an observed result, and planning illustrations are not observed power. The record does not report a completed analysis that would support an effect estimate or a confidence interval for treatment benefit or harm.
The most appropriate interpretation is therefore limited and descriptive: the registry documents the intended study, the enrollment achieved, the early termination, and the adverse-event information reported. It neither establishes benefit nor provides a precise estimate of risk. Conclusions beyond those observations are not supported by the registry record.
13. Why This Trial Matters Statistically
This trial is statistically instructive because it shows how early termination can sharply constrain what a planned study can answer. The design anticipated sequential evaluation at two IdeS dose levels, but the registry records enrollment only in the 0.25 mg/kg group. A dose comparison was therefore not observed, and the study could not provide the intended information from the higher-dose group.
The distinction between a study plan and an analysis result is also central. The record names several secondary outcomes, but explicitly says the protocol analyses were not performed. Listing a biomarker, pharmacokinetic measure, or antibody outcome does not show that it changed or that a test of change was completed. Readers need to separate intended measurements from reported findings.
The safety summaries highlight another general statistical lesson: percentages based on very few participants can be unstable and should not be treated as precise population estimates. A serious event observed in a small pilot is important descriptive information, but it cannot by itself establish incidence or causation. The reason for termination adds context to the record without resolving those statistical limitations.
Finally, non-randomized sequential dose groups are not interchangeable with randomized comparison groups. Even if both groups had enrolled, differences would need to be interpreted in light of the design and the order of treatment. The record demonstrates why study status, actual enrollment, event definitions, and analysis completion are necessary context when interpreting results—not just the names of endpoints or the numerical summaries.
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 principal limitation is the enrollment of 2 participants, with both listed in the IdeS (0.25 mg/kg) group and none in the IdeS (0.50 mg/kg) group. This leaves no observed higher-dose group and no randomized comparator. The non-randomized, sequential design also does not support a like-for-like comparison between dose groups.
The study was terminated early, and the registry states that the protocol analyses were not performed. As a result, the record does not provide completed estimates for the planned primary and secondary outcomes. The reasons for any missing outcome data, completeness of follow-up, analysis populations, missing-data methods, multiplicity handling, and statistical model specifications are not reported in the registry record.
The primary outcome relies on adverse events identified through spontaneous reports, responses to open questions, or observation. Such approaches define how events could be captured, but the registry information does not establish how completely events were ascertained or how event attribution was assessed. The record defines TEAEs and describes a broader post-treatment event period, so the precise event window should be kept in mind when reading the safety summaries.
Results from this small pilot cannot provide a precise estimate of event frequency in a broader population. The reported serious-event terms and percentages are descriptive, and they do not establish causation. Further participant characteristics, eligibility details, a protocol sample-size justification, and additional analysis methods are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: IdeS in Asymptomatic Antibody-Mediated Thrombotic Thrombocytopenic Purpura (TTP) Patients — NCT02854059.
- Registry record last updated 2019-09-13; status last verified 2019-09.
- Results first posted 2019-09-13.
- 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
NCT02854059, titled IdeS in Asymptomatic Antibody-Mediated Thrombotic Thrombocytopenic Purpura (TTP) Patients, was a Phase II pilot sponsored by Hansa Biopharma AB. It was listed as non-randomized, unmasked, and sequential. The study evaluated a single intravenous dose of IdeS in asymptomatic antibody-mediated TTP patients with low ADAMTS13 activity.
The registry records 2 participants enrolled, both in the IdeS (0.25 mg/kg) group, and none in the IdeS (0.50 mg/kg) group. The study began in 2016-09, reached primary completion in 2017-01, and is listed as terminated. The stated primary outcome was safety and tolerability measured through adverse events from dosing until the end of follow-up on day 64.
The registry says the study ended prematurely because of a non-favourable risk-benefit profile in the first 2 patients and that the sponsor would no longer pursue the indication. The protocol analyses were not performed. The posted information is therefore limited to study details and descriptive safety reporting rather than completed statistical analyses of the planned outcomes.