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 Collection of Blood Samples From Patients With Relapsing MS Who Developed ITP After Receiving Lemtrada (NCT03784898), a na phase 4 study. The primary outcome is Number of Participants Who Provided Whole Blood Samples for DNA Extraction and Analysis.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03784898 |
| Phase | Phase 4 |
| Condition | Multiple Sclerosis |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 13 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Genzyme, a Sanofi Company |
| Results posted | Yes |
2. Clinical Question
Population
Participants with relapsing forms of multiple sclerosis (RMS) who had developed immune thrombocytopenic purpura (ITP) after Lemtrada treatment. The registry records 13 enrolled participants. This is a selected group defined by both the disease and the ITP history; it is not a sample of all people with RMS or all people treated with Lemtrada.
Intervention
Blood collection for future genetic testing and biomarker analysis. The primary objective was to collect samples for DNA analysis as part of a global biomarker project assessing pre-identified candidate single nucleotide polymorphisms associated with ITP development after Lemtrada treatment in RMS participants.
Comparator
There was no comparator group. The registry identifies a single-group study, with allocation listed as not applicable and masking listed as none. Participants were included because they had developed ITP after treatment; no group without ITP or untreated group is described for comparison.
Primary question
The primary outcome asks how many participants provided whole blood samples for DNA extraction and analysis at Baseline (Day 1). This is a sample-collection measure, not a test of treatment effectiveness or a reported analysis of genetic markers. The registry does not report the observed count for this outcome.
In practical terms, the study was designed to assemble biological material from a specific group of participants for later biomarker work. It does not establish whether candidate genetic markers are associated with ITP, because no genetic-analysis results are reported. Nor can a single-group collection study compare the occurrence of ITP across different treatments or participant groups. Its central question concerns sample collection, while the intended scientific questions about genetic variation belong to future analysis.
3. Trial Design
NCT03784898 is listed as a completed Phase 4 study sponsored by Genzyme, a Sanofi Company. The recorded start date is 2019-02-08, and the primary completion date is 2019-12-11. The registry lists 13 enrolled participants. The study title and description concern people with relapsing forms of multiple sclerosis who developed ITP after Lemtrada treatment.
The design is identified as single-group, with allocation listed as not applicable and masking as none. The intervention is classified as other and described as a blood draw for future biomarker analysis. The registry describes a group of participants diagnosed with ITP; it does not identify a randomized control arm or a comparison group. Accordingly, the design is not a like-for-like treatment comparison. It is a sample-collection study rather than a trial that assigns participants to competing treatments.
The primary outcome is scheduled at Baseline (Day 1) and counts participants who provided whole blood samples for DNA extraction and analysis. The registry says participants with RMS who developed ITP after Lemtrada were included and gave samples for future genetic testing and biomarker analysis. However, it does not report the numerical result for the primary outcome. Enrollment of 13 is not itself a reported count of participants meeting that outcome.
The registry record does not report the eligibility criteria in detail, recruitment locations, a planned sample-size justification, or a statistical analysis plan. It also does not describe a control-group procedure or masking procedures beyond listing masking as none. These omissions limit what can be reconstructed about how participants were selected and how the collection objective was to be evaluated.
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: A total of 13 participants were enrolled in the study.
Overall Study
| Stage | Participants Diagnosed With ITP |
|---|---|
| STARTED | 13 |
| COMPLETED | 13 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: Analysis was performed on all enrolled population.
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: Analysis was performed on all enrolled participants.
| Characteristic | Unit | Participants Diagnosed With ITP |
|---|---|---|
| Participants analysed | 13 | |
| Age, Continuous | years | 48.2 (SD 7.8) |
| Sex: Female, Male: Female | Participants | 10 |
| Sex: Female, Male: Male | Participants | 3 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 13 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants Who Provided Whole Blood Samples for DNA Extraction and Analysis, measured over Baseline (Day 1).
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants who provided whole blood samples for DNA extraction and analysis. Its timeframe is Baseline (Day 1), and its analysis population is described as all enrolled participants. The endpoint measures whether the planned collection took place; it does not measure ITP severity, treatment response, or the presence of a genetic association.
The collection description specifies a maximum total of 69 milliliter of whole blood per participant. It lists DNA PAXgene tubes for DNA preparation, RNA PAXgene tubes for RNA preparation, EDTA tubes for peripheral blood mononuclear cell isolation, an SST tube for serum preparation, and a K2EDTA tube for plasma preparation. The stated purpose of the DNA was future analysis. These details explain what the collection was intended to support, but they do not establish that every listed sample type was successfully obtained or processed for every participant.
A count is useful for documenting whether a collection objective was achieved. To interpret that count, readers need the observed value and a clear denominator. The registry records enrollment of 13, but does not report the primary endpoint count. It is therefore not possible to determine from the record how many enrolled participants met the endpoint definition.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a biomarker-oriented sample-collection study in participants with RMS who developed ITP after Lemtrada treatment. The primary outcome is a participant count for whole blood samples intended for DNA extraction and analysis. This outcome addresses whether samples were collected, not whether a treatment changed ITP risk or whether any genetic marker was associated with ITP.
The registry lists 13 enrolled participants, but does not report the observed value for the primary outcome. Enrollment and endpoint completion are different quantities: enrollment identifies the number who entered the study, while the endpoint concerns the number who met a specific sample-collection criterion. Without the reported endpoint value, the collection outcome cannot be quantified. The registry’s description that participants gave blood samples provides context, but it does not substitute for a numerical result tied to the primary endpoint.
No statistical analyses are listed. There is consequently no reported estimate of an association, treatment effect, uncertainty interval, or hypothesis test to interpret. The candidate single nucleotide polymorphisms are described as targets for future analysis in a global biomarker project. The registry does not report the results of that genetic analysis. It therefore cannot support a conclusion about whether any candidate marker was associated with ITP in this cohort.
The absence of a comparator is important. Because the study has one group selected for having developed ITP after treatment, it cannot directly compare ITP occurrence with a group that did not develop ITP or with a group receiving another treatment. The record also does not report a denominator of all treated RMS participants from which the frequency of ITP could be assessed. These design features mean that the study’s stated purpose should be read as collection for future research, not as a comparative evaluation of treatment outcomes.
General statistical interpretation: a confidence interval describes uncertainty around an estimate, and a hypothesis test assesses how compatible data are with a specified statistical model. Neither should be inferred when no estimate, interval, test, or analysis result is reported. Likewise, enrollment alone does not establish the precision of an unreported endpoint result. The registry’s sample-size assumptions describe a planning illustration rather than a result from this single-group collection study. No observed-power conclusion follows from the record.
The study can be understood as one step in a research process: assemble samples from a clinically defined group, then use those samples for a separate biomarker analysis. The record establishes the intended collection and future-analysis purpose. It does not report the molecular findings, a comparison of groups, or a quantified primary endpoint result. Interpretation should remain within those boundaries.
9. Statistical Methods Explained
What does the primary outcome count?
The registry identifies the primary outcome as a count of participants who provided whole blood samples for DNA extraction and analysis. In general, a count outcome reports how many individuals meet a defined condition. Here the condition is tied to sample provision, and the timeframe is Baseline (Day 1). The count is not a measurement of a biological response or of ITP occurrence. The registry’s outcome description names all enrolled participants as the analysis population, but it does not report the observed count.
Enrollment is not interchangeable with an outcome count. Enrollment records entry into the study; the endpoint requires participants to meet the sample-collection definition. If an endpoint value and an appropriate denominator are reported, readers can evaluate the collection result in the context of the study population. In this record, enrollment is 13, but the primary outcome value is not reported. No proportion or other derived quantity can therefore be stated from the posted results.
What can the design estimate?
The study is single-group, with allocation listed as not applicable and masking as none. General statistical principle: a comparative treatment effect requires information from groups that can be compared under an appropriate design and analysis. This record does not describe such groups. It documents a selected cohort with RMS and ITP after Lemtrada treatment, so it cannot estimate a comparative treatment effect from the design described.
The collection objective is also distinct from the future genetic question. Collecting DNA can make later analysis possible, but the collection itself does not establish whether a candidate marker is associated with ITP. A genetic association analysis would require marker measurements, an analysis population, a defined comparison or model, and reported results. Those analysis details and results are not reported in the registry record.
How should uncertainty be understood?
General statistical explanation: an estimate is a numerical summary of the data, while a confidence interval communicates the uncertainty associated with that estimate under a statistical procedure. A p-value, when reported, summarizes how compatible data are with a specified null model; it does not measure the probability that a treatment works or that a hypothesis is true. These concepts can help interpret reported analyses, but the registry lists no analyses and provides no primary outcome result, confidence interval, or p-value to interpret.
For a count outcome, the actual observed number and the population at risk of meeting the endpoint are central to interpretation. A count without a relevant denominator may be hard to compare across studies of different sizes. A percentage or rate should not be reconstructed unless its inputs and definition are available and the calculation is explicitly reported. No such endpoint result is given, so the enrolled count should not be converted into a claimed completion rate.
What do the sample-size assumptions mean?
The registry information describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. The stated convention is participants per arm for non-time-to-event outcomes; time-to-event calculations use a total number of events. These are assumptions for planning illustrations, not a description of the actual study’s design.
The distinction matters because the registered study is single-group and does not describe two-arm allocation. A two-arm planning framework does not turn this sample-collection cohort into a comparative trial, and it does not establish a sample-size justification for the study. The registry does not report a trial-specific sample-size justification. Any planning figures based on an observed effect are illustrations, not observed power and not evidence that the study was designed to detect a clinical or genetic effect. Numerical planning results are not reported in the registry record.
General statistical explanation: over-dispersion occurs when variability in count data exceeds what a chosen model assumes. It can make standard errors and uncertainty estimates too small if the model does not account for that extra variability. The registry does not report a count model, dispersion assessment, or analysis of the primary endpoint, so there is no basis to say whether over-dispersion was relevant to an analysis in this study.
What analyses are documented?
The registry lists one outcome measure and zero analyses. It does not report an analysis method for the primary outcome, adjustment for covariates, a hypothesis test, or a precision estimate. It also does not report interim analyses. When an analysis method is absent, readers cannot determine whether any planned model assumptions were checked, how missing endpoint data were handled, or whether any results were adjusted for other variables. Those are not details that can be reconstructed from the sample-collection description alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure: the number of participants who provided whole blood samples for DNA extraction and analysis. It lists zero analyses. A multiplicity adjustment is therefore not described, and the registry does not report whether any testing plan covered additional outcomes or future biomarker analyses. The stated future assessment of candidate single nucleotide polymorphisms is an objective for later work, not a set of reported results in this record. A family of tests, test hierarchy, or adjustment procedure is not reported in the registry record.
The record identifies all enrolled participants as the population for the primary outcome, but does not report the endpoint count or describe how missing sample-collection information was handled. It does not say whether any participant lacked an endpoint measurement, whether missing data were excluded or imputed, or whether a sensitivity analysis was planned. The enrollment figure of 13 does not resolve those questions.
General statistical explanation: missingness can affect an estimate when the availability of data is related to participant characteristics or outcomes. An analysis population definition and a transparent account of missing values help readers understand which participants contributed to a result. Here, the registry gives an intended analysis population but no reported result or missing-data method. No conclusion about the completeness of endpoint data can be drawn from the record.
The registry does not report an interim analysis plan, a statistical analysis plan, or a protocol-level description of multiplicity handling. These items should be treated as unreported rather than assumed absent from every study document. The available record does not establish whether additional analyses were planned outside the registry entry.
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 |
|---|---|---|---|
| Participants Diagnosed With ITP | 0 | 13 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Participants Diagnosed With ITP | 0 of 13 |
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 |
|---|---|
| Participants Diagnosed With ITP | 0 of 13 |
The registry lists 13 participants at risk for serious adverse events and 0 participants affected. It also lists 13 participants at risk for other adverse events and 0 affected. No serious adverse event terms are listed, and the death count is 0. These are the adverse-event figures recorded for the group diagnosed with ITP.
These figures describe what the registry reports; they are not the primary endpoint and do not report the DNA-sample collection result. The record does not provide a detailed adverse-event ascertainment window or further information about how events were collected and classified. The zero counts should therefore be read as zero events recorded in the registry categories, not as proof that no event occurred under every possible definition or outside the reported collection period.
General statistical explanation: when event counts are zero in a group of limited size, the observed count alone does not establish that the underlying event risk is zero. The amount of uncertainty depends on the study design, follow-up, and event ascertainment. No uncertainty interval or safety analysis is reported in this record. The figures support only a description of the registry’s recorded counts, not a broader comparative safety conclusion.
12. What the Result Does, and Does Not, Mean
The principal result available from the registry is a description of the study’s purpose and design: blood was collected from participants with RMS who developed ITP after Lemtrada treatment for future genetic and biomarker research. The primary endpoint was intended to count participants who provided whole blood for DNA extraction and analysis at Baseline (Day 1). The registry lists 13 enrolled participants but does not report the observed primary endpoint count. The endpoint result cannot be inferred from enrollment.
The study does not report genetic findings, an association estimate, or a comparison with participants who did not develop ITP. Its stated objective was to collect samples for later analysis of pre-identified candidate single nucleotide polymorphisms as part of a global biomarker project. The record therefore describes an enabling research step, not the outcome of that future analysis.
The design also does not answer whether Lemtrada changes the chance of ITP. All participants in the described group had RMS and developed ITP after Lemtrada treatment, and no untreated or alternative-treatment group is recorded. Without a comparison group and a suitable denominator of treated participants, the study cannot estimate the frequency of ITP among all people who received treatment or compare that frequency across groups.
General statistical interpretation: a study’s conclusion must match its design and reported outcomes. Sample collection may support later research, but the scientific claim from a collection study is limited to the collection objective and its documented results. Since the primary outcome value and genetic-analysis results are not reported, the extent to which the endpoint was achieved and the findings of the intended biomarker work remain unknown from this registry record.
The safety counts are also limited to the categories and group recorded: 0 serious adverse events, 0 other adverse events, and 0 deaths, among 13 at risk in each adverse-event category. They do not add evidence about genetic associations or treatment comparisons. Overall, the record establishes the study’s rationale, cohort description, and collection purpose, while leaving the quantitative collection result and future biomarker findings unreported.
13. Why This Trial Matters Statistically
This study illustrates a distinction that is important in clinical research: a trial can be designed to collect material for later analysis without testing a treatment hypothesis in the enrolled cohort. Here, the stated objective was collection of blood samples from participants with RMS who developed ITP after Lemtrada treatment, to support future DNA and biomarker work. The clinical question represented by the primary endpoint is whether participants provided samples for analysis, not whether a treatment changed an outcome.
The distinction also clarifies what a registry entry can and cannot establish. The record gives an enrollment count of 13 and describes the planned sample collection, but it does not report the observed count for the primary endpoint or analyses of candidate genetic markers. Statistical interpretation depends on the result actually reported, not on the intention to conduct future work. Keeping those stages separate prevents an objective from being mistaken for a finding.
The single-group design is consequential. Because no comparison group is described, the cohort cannot by itself support an estimate comparing ITP occurrence across treatments or between people with and without ITP. General statistical principle: the population from which participants are selected determines which questions an estimate can address. A group selected for having the condition of interest is useful for some forms of characterization, but it does not supply the denominator needed to estimate the condition’s frequency among all treated participants.
The record also demonstrates why transparent reporting of endpoint values and analysis methods matters. Without the primary count, readers cannot quantify the collection outcome. Without reported genetic results or methods, readers cannot assess the intended biomarker question. The study’s statistical importance lies in its research role and its design boundaries, rather than in a treatment-effect result that the registry does not report.
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 most direct limitation for interpreting the primary endpoint is that its observed count is not reported. Although the registry lists 13 enrolled participants and describes blood-sample collection, enrollment is not a substitute for the endpoint result. The record does not state how many participants met the endpoint definition or provide a numerical account of completed collections.
The single-group design has no listed comparator, and the participants were selected because they had developed ITP after Lemtrada treatment. This limits what can be learned about comparative treatment outcomes or ITP occurrence in a broader treated population. The record does not provide a denominator of all RMS participants treated with Lemtrada, or a group of treated participants who did not develop ITP.
The stated biomarker work was for future analysis. Genotype results, assay methods, association models, and estimates for candidate markers are not reported in the registry record. The record also lists zero analyses, so there is no reported estimate or uncertainty assessment for the genetic objective.
Other details that would help assess the study are not reported in the registry record, including detailed eligibility criteria, a trial-specific sample-size justification, a statistical analysis plan, and methods for handling missing endpoint data. The registry identifies all enrolled participants as the primary outcome population but does not document endpoint completeness. Adverse-event follow-up and ascertainment details are likewise not described in the information recorded. These limitations do not change the stated purpose of the study, but they restrict how much can be concluded from its registry entry.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Collection of Blood Samples From Patients With Relapsing MS Who Developed ITP After Receiving Lemtrada — NCT03784898.
- Registry record last updated 2022-03-28; status last verified 2022-03.
- Results first posted 2020-07-20.
- 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
NCT03784898 is a completed Phase 4, single-group study sponsored by Genzyme, a Sanofi Company. The registry lists 13 enrolled participants and records a start date of 2019-02-08 and a primary completion date of 2019-12-11. Participants had RMS and developed ITP after Lemtrada treatment.
The study’s objective was to collect blood samples for future DNA and biomarker analysis. Its primary outcome counts participants who provided whole blood for DNA extraction and analysis at Baseline (Day 1). The registry does not report the observed primary outcome count or any statistical analyses. The genetic-analysis findings are not reported.
No comparator group is described. The registry records 0 serious adverse events, 0 other adverse events, and 0 deaths. These counts do not constitute a comparative safety analysis. The record’s central contribution is its description of a sample-collection cohort intended to support future biomarker research; it does not report a treatment-effect or genetic-association result.