This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Study of a Single Dose of ALXN1210 in Healthy Participants (NCT05288660), a randomized phase 1 study. The primary outcome is Number of Participants With Treatment Emergent Adverse Events (TEAEs).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05288660 |
| Phase | Phase 1 |
| Condition | Healthy |
| Allocation | Randomized |
| Design model | Sequential |
| Masking | Triple |
| Enrollment | 14 |
| Arms in the primary outcome | 3 |
| Lead sponsor | Alexion Pharmaceuticals, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Healthy participants who received a dose of study drug formed the safety population. The registry lists enrollment of 14 participants.
Intervention
Participants received a single intravenous dose of ALXN1210. The registry describes cohorts receiving 200 mg or 400 mg.
Comparator
The comparator was intravenous placebo. The registry lists a placebo group alongside the two ALXN1210 dose cohorts.
Primary question
The primary endpoint counted participants with treatment-emergent adverse events from baseline up to Day 150. The endpoint definition includes events beginning after administration and events that began before dosing but worsened in frequency or severity afterward.
In statistical terms, this is a safety-focused, early-phase question: how many participants in each listed group had at least one event meeting the registry’s treatment-emergent definition during the stated observation period? The posted counts are descriptive. They do not by themselves establish whether an event was caused by study drug, and the endpoint description says adverse events are summarized regardless of causality.
The study also evaluated pharmacokinetics and pharmacodynamics, and its listed secondary outcomes include serum concentration measures and related parameters. Those outcomes address different questions from the primary safety count. This page does not treat them as evidence about the primary endpoint, nor does it infer unposted results for them. The registry record does not report a statistical comparison for the primary endpoint, so the central question is how to read the group counts and what they can—and cannot—show.
3. Trial Design
The registry describes a Phase 1, randomized, blinded, placebo-controlled, single-ascending-dose study of intravenous ALXN1210 in healthy participants. Its allocation is listed as randomized, its masking as triple, and its model as sequential. The two active-dose cohorts were ALXN1210 200 mg and ALXN1210 400 mg; the comparator was intravenous placebo. The record does not specify which roles were masked or provide further details about the sequence of cohort enrollment.
Enrollment is listed as 14. The primary endpoint safety population is defined as participants who received any dose of ALXN1210 or placebo. The posted group summaries show 4 participants in the 200 mg cohort, 6 in the 400 mg cohort, and 4 in the placebo group. These group sizes are small, so the observed counts provide only a limited description of event experience in this study. They should not be read as precise estimates of event frequency in a broader population.
The registry lists the study as completed, with a start date of 2014-08-27 and a primary completion date of 2015-03-13. Its brief summary says safety, tolerability, pharmacokinetics, and pharmacodynamics were evaluated using electrocardiograms, physical examination, vital signs, laboratory analysis, and adverse-event assessment. The registry record does not report the detailed dosing sequence, the allocation procedure, or a sample-size justification. The analysis plan and any interim-analysis procedures are also not reported in the registry record.
The posted results include primary endpoint counts by group and separate adverse-event summaries. They do not include a reported inferential comparison for the primary endpoint. The tables and plots on this page display those posted data; the accompanying text emphasizes their descriptive nature rather than interpreting them as a confirmatory treatment comparison.
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 | Cohort 1: ALXN1210 200 mg | Cohort 2: ALXN1210 400 mg | Placebo |
|---|---|---|---|
| STARTED | 4 | 6 | 4 |
| Received at Least 1 Dose of Study Drug | 4 | 6 | 4 |
| COMPLETED | 4 | 6 | 4 |
| NOT COMPLETED | 0 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The safety population included the group of participants who received any dose of the study drug (ALXN1210 or placebo).
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: The safety population was defined as the group of participants who received any dose of the study drug (ALXN1210 or placebo).
| Characteristic | Unit | ALXN1210 200 mg | ALXN1210 400 mg | Placebo | Total |
|---|---|---|---|---|---|
| Participants analysed | 4 | 6 | 4 | 14 | |
| Age, Continuous | years | 44.0 (SD 9.42) | 41.8 (SD 8.33) | 46.3 (SD 8.34) | 43.7 (SD 8.18) |
| Sex: Female, Male: Female | Participants | 2 | 3 | 2 | 7 |
| Sex: Female, Male: Male | Participants | 2 | 3 | 2 | 7 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Treatment Emergent Adverse Events (TEAEs), measured over Baseline up to Day 150.
| 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 with treatment-emergent adverse events (TEAEs), measured from baseline up to Day 150. It counts participants, rather than the total number of individual events. A participant is included if an adverse event occurred on or after study-drug administration, or if an event that began before dosing worsened in frequency or severity after administration.
This kind of endpoint is used to summarize safety experience over a defined period. Counting participants with at least one qualifying event provides a straightforward overview of how many people in each group experienced an event meeting the definition. It does not describe how many separate events each participant had, how severe each event was, or whether an event was judged related to treatment. The registry description says the TEAE summary is regardless of causality and directs readers to the reported adverse-events section for serious and other adverse events.
Because the outcome is a count of participants with an event, interpretation depends on the group size as well as the event count. The posted summaries give both. With small groups, a count can change substantially when the experience of an individual participant differs; the summaries therefore need to be read as observations from this study, not as a stable estimate for other populations. No confidence interval or statistical comparison for this endpoint is reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary endpoint counts are 3 of 4 participants in the ALXN1210 200 mg cohort, 4 of 6 in the ALXN1210 400 mg cohort, and 4 of 4 in the placebo group. These are the registry’s observed group summaries for participants with TEAEs. They are not adjusted estimates, and the record does not report a statistical test or confidence interval comparing the groups.
The counts show that participants with at least one qualifying event were recorded in every group, including placebo. The observed counts alone do not establish causality. The endpoint includes events regardless of causality, and the registry’s definition also includes a pre-dose event if it worsened after dosing. The counts therefore describe event experience under the endpoint rule, not a judgment that study drug caused each event.
The group sizes are small, and the data do not support a precise estimate of how often such events would occur in a larger or different population. A small change in the experience of one participant would alter a group’s count. The registry record does not report uncertainty intervals that would quantify the precision of the group summaries, and no inferential result is posted for the two-arm comparison. The comparison and planning displays should be understood in that context; they do not add an unreported analysis to the registry results.
Other posted safety summaries separate serious adverse events from other, nonserious adverse events. The serious-event summary records 1 affected participant among 4 in the 200 mg group, none among 6 in the 400 mg group, and none among 4 in placebo. The corresponding other adverse-event counts are 3 among 4, 4 among 6, and 4 among 4. These are separate summaries and should not be combined or assumed to represent mutually exclusive participants without further detail. The record lists no deaths in any group.
The registry also lists pharmacokinetic measures, including maximum serum concentration, time to maximum concentration, and area-under-the-curve measures. The presence of these outcomes in the record does not establish their results; the numerical results for them are not described. Overall, the posted safety counts are useful for understanding what was observed among the enrolled participants, but they do not provide a precise or causal estimate of treatment differences.
9. Statistical Methods Explained
The primary outcome is binary at the participant level: each participant either met the registry’s TEAE definition during the stated timeframe or did not. The posted data therefore consist of a participant count with an event and a group size. They are descriptive counts, not a continuous measurement such as a concentration or laboratory value. The registry reports no analysis results for a two-arm comparison, so this page does not present a test statistic, p-value, confidence interval, or adjusted estimate for the primary endpoint.
What does a confidence interval describe?
In general, a confidence interval expresses the uncertainty around an estimate under a specified statistical model and procedure. It is not a guarantee that a treatment effect lies within its limits, nor does it show that an observed difference is clinically important. Here, the registry record does not report confidence intervals for the primary endpoint. The small group sizes also mean that any estimate based on these participants would need to be interpreted with particular caution. The posted counts should not be mistaken for precise estimates of event frequency beyond this study.
Why can event counts be difficult to compare?
For a binary endpoint, a comparison often summarizes how the chance of an event differs between groups. That comparison requires a defined estimand and an analysis method. The record does not report those details for the primary endpoint, and it does not post an inferential comparison. The code-generated displays organize the arm-level results, but the absence of a reported comparison means that the counts should be read on their own rather than as evidence of a statistically established difference.
The three listed groups also include two active-dose cohorts and a placebo group. The study’s sequential model and ascending-dose description provide design context, but the registry record does not explain whether or how the dose cohorts were compared jointly, whether a dose trend was evaluated, or what adjustment would be used for multiple comparisons. A reader should not infer such procedures from the design labels alone.
What does over-dispersion mean in general?
Over-dispersion is a general concern when observed variability is greater than a statistical model expects. It is particularly relevant to count outcomes modeled as event counts, because unmodeled variability can make uncertainty appear too small. The primary endpoint counts participants with at least one event rather than the total number of events, so an over-dispersion model is not automatically implied by the endpoint definition. The registry record does not report a model for the primary endpoint, and there is no basis to claim that over-dispersion was assessed or addressed.
How should the sample-size display be read?
The sample-size section on this page is a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Its stated purpose is to illustrate the number of participants per arm for a chosen fraction of the observed effect. It is not the trial’s actual design calculation, not the number enrolled, and not observed power. The registry record does not report the study’s own sample-size justification. In addition, the registry indicates that values are missing or not estimable for a two-arm comparison of this binary outcome, so the illustration should not be interpreted as a substitute for an unavailable comparison.
Planning calculations based on an observed effect can be unstable, especially when group sizes are small. They describe hypothetical planning under stated assumptions; they do not show that the study had a particular probability of finding a result. The trial’s enrollment and the planning illustration answer different questions. No sample-size values beyond those shown in the code-generated section are introduced in this explanation.
What is the role of the posted counts?
The counts retain their direct meaning: they report how many participants in each group met the TEAE definition. They do not reveal the number of events per participant, event timing within the observation period, duration, severity, or attribution. Those details are not reported in the primary endpoint summary. The adverse-event section provides separate serious and other-event summaries, but those summaries do not supply the full participant-level event history. In general, interpreting a safety outcome requires attention to its definition, observation period, group sizes, and uncertainty. In this record, the first three are described, while an inferential analysis and several event-level details are not reported.
10. Exact Estimates for Each Arm
No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.
| Arm | Participants | Events | Observed % | Clopper-Pearson 95% CI | Wilson 95% CI | Bayesian 95% credible interval |
|---|---|---|---|---|---|---|
| Cohort 1: ALXN1210 200 mg | 4 | 3 | 75.0% | 19.4% to 99.4% | 30.1% to 95.4% | 28.4% to 94.7% |
| Cohort 2: ALXN1210 400 mg | 6 | 4 | 66.7% | 22.3% to 95.7% | 30.0% to 90.3% | 29.0% to 90.1% |
| Placebo | 4 | 4 | 100.0% | 39.8% to 100.0% | 51.0% to 100.0% | 47.8% to 99.5% |
R code and output
arm <- c("Cohort 1: ALXN1210 200 mg", "Cohort 2: ALXN1210 400 mg", "Placebo")
n <- c(4, 6, 4)
events <- c(3, 4, 4)
for (i in seq_along(n)) {
ci <- binom.test(events[i], n[i])$conf.int # Clopper-Pearson exact interval
cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i]) # Bayesian, uniform Beta(1,1) prior
wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}
ARM Cohort 1: ALXN1210 200 mg 4 3 75.0 19.4 99.4 30.1 95.4 28.4 94.7
ARM Cohort 2: ALXN1210 400 mg 6 4 66.7 22.3 95.7 30.0 90.3 29.0 90.1
ARM Placebo 4 4 100.0 39.8 100.0 51.0 100.0 47.8 99.511. Multiplicity, Missing Data and Analysis Populations
The registry lists secondary outcomes covering pharmacokinetic measures such as maximum observed serum concentration, time to maximum concentration, area under the serum concentration curve, terminal elimination parameters, clearance, and volume of distribution. It reports 15 posted secondary outcomes and 16 outcome measures overall. The registry record does not report a multiplicity procedure, such as an adjustment or hierarchy for interpreting several outcomes. It also does not report whether secondary outcomes were treated as exploratory or confirmatory. Without that information, readers should not treat a set of outcome findings as if it were a single prespecified test.
The record does not describe a missing-data method for the primary endpoint, how participants without complete follow-up were handled, or whether any endpoint values were missing. The primary endpoint timeframe is baseline up to Day 150, but the registry’s summary does not provide individual follow-up durations or completeness. These details are not reported in the registry record, so the displayed counts cannot establish how missing observations may have been handled.
The safety population is defined as participants who received any dose of study drug. The record does not describe an intention-to-treat population or another analysis population for the primary endpoint, nor does it provide further rules for inclusion beyond the stated safety-population definition. It reports 0 analysis results for the posted record. This is distinct from the arm-level endpoint and adverse-event summaries, which are descriptive results rather than a reported inferential analysis.
12. 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 |
|---|---|---|---|
| ALXN1210 200 mg | 1 | 4 | 25.0% |
| ALXN1210 400 mg | 0 | 6 | 0.0% |
| Placebo | 0 | 4 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| ALXN1210 200 mg | 0 of 4 |
| ALXN1210 400 mg | 0 of 6 |
| Placebo | 0 of 4 |
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 |
|---|---|
| ALXN1210 200 mg | 3 of 4 |
| ALXN1210 400 mg | 4 of 6 |
| Placebo | 4 of 4 |
Most frequent serious adverse event terms
| Event term | Organ system | ALXN1210 200 mg | ALXN1210 400 mg | Placebo |
|---|---|---|---|---|
| Myocardial Infarction | Cardiac disorders | 1 of 4 | 0 of 6 | 0 of 4 |
Most frequent non-serious adverse event terms
| Event term | Organ system | ALXN1210 200 mg | ALXN1210 400 mg | Placebo |
|---|---|---|---|---|
| Headache | Nervous system disorders | 0 of 4 | 3 of 6 | 3 of 4 |
| Infusion Site Pain | General disorders | 1 of 4 | 1 of 6 | 1 of 4 |
| Nasopharyngitis | Infections and infestations | 0 of 4 | 1 of 6 | 2 of 4 |
| Oropharyngeal Pain | Respiratory, thoracic and mediastinal disorders | 0 of 4 | 1 of 6 | 1 of 4 |
| Rhinorrhoea | Respiratory, thoracic and mediastinal disorders | 0 of 4 | 1 of 6 | 1 of 4 |
| Throat Irritation | Respiratory, thoracic and mediastinal disorders | 0 of 4 | 1 of 6 | 1 of 4 |
| Upper Respiratory Tract Infection | Infections and infestations | 0 of 4 | 1 of 6 | 1 of 4 |
| Back Pain | Musculoskeletal and connective tissue disorders | 0 of 4 | 0 of 6 | 2 of 4 |
| Dyspepsia | Gastrointestinal disorders | 0 of 4 | 1 of 6 | 1 of 4 |
| Nausea | Gastrointestinal disorders | 0 of 4 | 1 of 6 | 1 of 4 |
Serious events with the highest arm-level rate: myocardial infarction (25.0%).
The serious adverse-event summary records 1 affected participant among 4 in the ALXN1210 200 mg group, 0 among 6 in the ALXN1210 400 mg group, and 0 among 4 in the placebo group. The record lists 0 deaths in each group. It also identifies “Myocardial Infarction” in its list of top serious-event terms with 25.0%; the registry summary does not provide further context for that percentage here, so it should be read as a reported listing rather than used to infer an event rate or a treatment relationship.
These figures describe the participants recorded as affected in each group. They do not establish that an event was caused by study drug, and the record does not provide enough detail to assess timing, clinical course, or attribution. The absence of a recorded serious event in a group does not establish that the risk is absent; it means no affected participant was recorded in that group in this study’s posted summary.
The other adverse-event summary records 3 affected participants among 4 in the 200 mg group, 4 among 6 in the 400 mg group, and 4 among 4 in placebo. The primary TEAE endpoint is a separate summary, and the record does not clarify the overlap of individual participants across the serious and other-event categories. These counts should not be added together or interpreted as unique participants across categories.
13. What the Result Does, and Does Not, Mean
The posted results answer a narrow descriptive question: how many participants in each group were recorded as having a TEAE during the specified period? The counts are 3 of 4 in the 200 mg cohort, 4 of 6 in the 400 mg cohort, and 4 of 4 in placebo. The registry also reports serious and other adverse-event counts separately. These results describe the enrolled participants and the event definitions used in the record.
They do not establish whether ALXN1210 caused any particular event. The primary endpoint includes events regardless of causality, and the registry record does not post a statistical comparison or uncertainty interval for the primary endpoint. The data therefore do not show a statistically established difference between groups, nor do they establish equivalence. A lack of a posted comparison is not evidence that the groups are the same.
The results also do not determine what event frequency would be expected in a larger, different, or less selected population. The study enrolled healthy participants and was a Phase 1 single-dose study. The small group sizes make the observed counts particularly sensitive to individual participants’ outcomes. The registry’s status of completed and its enrollment figure do not fill in missing analysis details or supply a broader estimate of safety.
The listed pharmacokinetic and pharmacodynamic objectives are relevant to the study’s scope, but they should not be confused with the posted TEAE counts. Numerical results for those secondary outcomes are not. Similarly, a planning illustration in the sample-size section is not observed power and does not add evidence about the treatment effect. The most defensible reading is limited: these are descriptive safety observations from the groups and follow-up period stated in the registry record, with important inferential and event-level details not reported.
14. Why This Trial Matters Statistically
This study illustrates why a safety summary should be read together with its endpoint definition and denominator. A count of participants with TEAEs is easy to understand, but it is not a complete description of the number, severity, timing, or causes of events. The registry’s definition includes events occurring after administration and events that began earlier but worsened after dosing. That definition matters when interpreting the posted counts.
The study also shows the distinction between descriptive results and inferential comparisons. Group-level counts are posted, but the registry record does not report a statistical comparison for the primary endpoint. Without an estimate of uncertainty or a stated analysis, readers should avoid turning the observed counts into a definitive claim about differences between groups. Small groups make that caution especially important.
Finally, the trial’s early-phase, single-dose setting helps clarify what the results can address. The registry describes randomized, blinded, placebo-controlled evaluation in healthy participants, with safety and pharmacokinetic and pharmacodynamic objectives. These features frame the study’s purpose, but they do not replace the information needed to interpret a treatment effect, such as a reported analysis plan, missing-data approach, or multiplicity procedure. The record makes clear why transparent reporting of both observed counts and analytic context is important for statistical interpretation.
15. 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.
Several limitations arise directly from what the registry record reports and does not report. The primary endpoint is summarized with group counts, but there is no posted inferential comparison, confidence interval, or p-value. This prevents readers from evaluating an estimated difference together with its statistical uncertainty. The small group sizes further limit how precisely the observed event experience can represent anything beyond the participants in this study.
The endpoint counts participants with at least one TEAE, not the total number of events. The primary summary does not provide event-level timing, duration, severity, recurrence, or attribution. Although a separate adverse-event summary reports serious and other events, the record does not explain participant overlap between those categories. The top serious-event listing gives a term and percentage, but further context for that percentage is not reported in the registry record.
The record identifies a safety population but does not report a missing-data procedure, completeness of follow-up, or participant-level exclusions. It also does not report the detailed statistical analysis plan, any multiplicity approach, or the trial’s sample-size justification. The sequential model is named, but the record does not provide the operational details needed to assess how the cohorts were conducted or analyzed. Finally, the study’s population and single-dose design constrain the scope of interpretation: the posted results concern healthy participants in this study and should not be generalized beyond that setting on the basis of these counts alone.
16. Related Tutorials
17. Related Statistical Calculators
18. Sources
- ClinicalTrials.gov: A Study of a Single Dose of ALXN1210 in Healthy Participants — NCT05288660.
- Registry record last updated 2023-05-09; status last verified 2022-06.
- Results first posted 2023-05-09.
- 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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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
19. Record Summary
This is a completed Phase 1 randomized, triple-masked, placebo-controlled, sequential, single-ascending-dose study of intravenous ALXN1210 in healthy participants. The registry lists enrollment of 14, with cohorts receiving ALXN1210 200 mg or 400 mg and a placebo group. The primary endpoint is the number of participants with TEAEs from baseline up to Day 150.
The posted TEAE counts are 3 of 4 in the 200 mg cohort, 4 of 6 in the 400 mg cohort, and 4 of 4 in placebo. Serious adverse-event and other adverse-event summaries are also posted; the registry lists no deaths. No inferential analysis for the primary endpoint is reported in the registry record. The study also lists pharmacokinetic and pharmacodynamic objectives, but this explanation focuses on the available safety counts and their limits.