Phase IIa Trial of ALXN1007 for the Treatment of Non-criteria Manifestations of Antiphospholipid Syndrome: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Phase IIa Trial of ALXN1007 for the Treatment of Non-criteria Manifestations of Antiphospholipid Syndrome (NCT02128269), a na phase 2 study. The primary outcome is Safety and Tolerability of Intravenous (IV) ALXN1007 as Measured by Percentage of Patients Reporting Adverse Events.

2. Clinical Question

This question concerns adverse events in the treated group, not a contrast in event rates between treatments. The primary measure is framed as a percentage of patients reporting adverse events, while the posted outcome measure is expressed as a participant count. Those descriptions identify the outcome's focus, but the record does not report an analyzed percentage, a confidence interval, or a statistical comparison. It also does not give a separate efficacy endpoint in the posted results.

The clinical population is defined by persistent aPL positivity and the stated non-criteria manifestations. The record does not report further detail about how those manifestations were assessed or how participants were selected. Findings should therefore be read in the context of this described population and this open-label, single-group design, rather than as a controlled comparison or as a result for a broader population.

3. Trial Design

The registry record describes NCT02128269 as a Phase IIa, open-label, single-group study of ALXN1007. It records no masking and no randomized allocation. The intervention is listed as a biological study drug, and the brief summary specifies intravenous administration. With no comparator group, the design can describe events recorded among participants receiving ALXN1007, but it cannot isolate the treatment's effect from other explanations through a concurrent control comparison.

The stated study purpose was to evaluate safety and tolerability in persistently aPL-positive patients with at least 1 of the listed non-criteria manifestations of antiphospholipid syndrome: aPL-nephropathy, skin ulcers and/or thrombocytopenia. Enrollment is recorded as 9. The primary outcome is titled as the percentage of patients reporting adverse events, with a timeframe of Treatment Period (24 weeks). The registry also presents counts of participants affected by serious and other adverse events.

The record gives a study start of 2014-04 and a primary completion date of 2016-06. Its status is TERMINATED. The reason for termination, the circumstances of the termination, and whether termination affected the availability or completeness of outcome data are not reported in the registry record. Those details should not be inferred from the status alone.

No statistical analysis is listed, and no analyses are reported. The registry record does not state a planned sample-size justification, a statistical analysis plan, interim analyses, or a prespecified method for comparing outcomes. The planning assumptions associated with sample-size illustrations are not a substitute for such a plan and do not describe the observed single-group design. Any planning illustration is not observed power and should not be read as an analysis of this trial.

Because the study has no control arm, adverse-event counts are descriptive. Differences from an external group or from background expectations are not established by these results. The open-label design also means that masking cannot limit knowledge of treatment assignment; the record does not report procedures intended to address that issue.

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.

Treatment Period

Reasons for not completing this period:

Follow-up

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.

6. Primary Endpoint

The registry lists the primary outcome as Safety and Tolerability of Intravenous (IV) ALXN1007 as Measured by Percentage of Patients Reporting Adverse Events, measured over Treatment Period (24 weeks).

The primary outcome is titled “Safety and Tolerability of Intravenous (IV) ALXN1007 as Measured by Percentage of Patients Reporting Adverse Events.” Its unit is participants, its measure is a count of participants, and its stated timeframe is Treatment Period (24 weeks). In plain terms, the outcome is intended to describe how many participants report adverse events during treatment, expressed in the title as a percentage of patients.

Safety and tolerability measures are used to characterize adverse events observed while participants receive an intervention. They can describe the kinds of events recorded and how many participants are reported as affected. Such summaries are important descriptive information, but they do not by themselves establish that an intervention caused an event or that an intervention changed event risk. A comparison group and an analysis plan would be needed to support a comparative treatment-effect interpretation.

The posted results give participant counts for serious adverse events and other adverse events, while the primary outcome title refers to a percentage. The registry record does not report a separately analyzed percentage, a confidence interval, or a statistical test for the primary outcome. It also does not specify in the posted outcome description how adverse events were defined, assessed, or attributed. The available figures therefore support a descriptive reading of the recorded safety data, not a precise estimate of a comparative treatment effect.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record reports an outcome measured as participant counts and does not list any analyses. The methods concepts below are general explanations of how safety outcomes are often interpreted; they are not claims about methods used in this trial. The statistical analysis plan, if any, is not reported in the registry record.

What a participant count describes

A participant count records how many people in the group are classified as having an event under the outcome definition. It is a descriptive summary. A count does not show the timing, duration, severity, or recurrence of events unless those features are separately reported. The registry provides counts of participants affected by serious and other adverse events, but the posted record does not provide further detail on event-level timing or recurrence.

The primary outcome title describes a percentage, while the measure is recorded as a count of participants. In general, a percentage relates an affected count to a defined denominator. The choice of denominator matters: it may depend on who was assessed for the outcome and over what period. Here the registry reports a group at risk of 9 and the relevant affected counts, but does not provide an analyzed percentage or explain any denominator handling for missing outcome data. No percentage should be inferred beyond the values explicitly displayed in the registry record.

Why uncertainty matters

A confidence interval is a general statistical tool for expressing uncertainty around an estimated quantity. It gives a range of values compatible with the data under the assumptions of the method. An interval's width reflects precision: wider intervals indicate less precise estimation. The registry record does not report a confidence interval for the primary safety outcome or for the adverse-event counts. Consequently, readers cannot use the posted results to assess the interval-based precision of an estimated event rate.

A statistical test asks how compatible the observed data are with a specified null hypothesis under a model. A p-value is not the probability that a treatment works or that an observed event was caused by treatment. It also does not measure the clinical importance of an effect. Since the registry lists no analyses and reports no p-value for the primary outcome, there is no reported hypothesis test to interpret.

What a single-group design can establish

In a single-group design, outcomes can be described for the enrolled group, but there is no concurrent control group to estimate what would have happened under a different treatment or without the study intervention. General comparisons with external data can be affected by differences in participants, outcome definitions, observation periods, and follow-up. No external comparison is reported for this study. The open-label design also means treatment assignment was not masked; whether that affected event reporting or assessment is not established by the registry record.

For a comparative treatment-effect analysis, a prespecified contrast and a suitable statistical method are generally needed. This record reports neither a comparator nor an analysis. The observed counts therefore do not estimate a risk difference, relative effect, or other between-group quantity. No such quantity should be inferred from them.

Why event classification and follow-up matter

Safety summaries depend on how events are defined, collected, classified, and attributed. General considerations include whether an event is counted once per participant or each time it occurs, how seriousness is determined, how the observation window is set, and how missing follow-up is handled. These details can affect the meaning of a count. The outcome description identifies adverse events and a 24-week treatment period, but the registry record does not report the operational definitions or procedures used for these matters.

Serious adverse events and other adverse events are distinct summaries in the registry. They should not automatically be treated as mutually exclusive participant groups: a participant could contribute to more than one type of summary unless the reporting rules say otherwise. The record does not describe the relationship between these categories or provide participant-level event data. For that reason, counts should be considered separately rather than combined or interpreted as a complete partition of participants.

Planning assumptions are not trial results

In general, sample-size planning uses assumptions about a target effect, variability or event frequency, statistical significance, power, and design. A planning illustration based on an observed effect is not an observed-power analysis and does not show how likely the trial was to detect a real effect. The assumptions recorded for a planning illustration include a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions do not match the recorded single-group design with no like-for-like control comparison. No trial-specific sample-size justification or analysis plan is reported in the registry record.

The record reports no inferential analyses, adjusted estimates, or analysis populations. It is therefore not possible to assess the fit of a statistical model, verify an adjustment strategy, or determine how the analysis treated missing data. These absences limit the statistical interpretation to the descriptive information recorded for the group.

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.

R code and output

arm    <- c("ALXN1007")
n      <- c(9)
events <- c(8)
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  ALXN1007  9  8  88.9  51.8  99.7  56.5  98.0  55.5  97.5

11. Multiplicity, Missing Data and Analysis Populations

Multiplicity concerns arise when a study tests or estimates many outcomes, subgroups, time points, or comparisons. In general, repeated testing can increase the chance of at least one apparently notable result arising by chance. Statistical plans may address this with prespecified outcome hierarchies, adjusted testing procedures, or a clear distinction between confirmatory and exploratory analyses. No multiplicity strategy or analysis plan is reported in the registry record.

The record lists 1 outcome measure and 0 analyses. It does not report multiple hypothesis tests for the primary outcome, so there is no reported testing family or adjustment method to interpret. The record also does not explain whether additional outcomes or analyses were planned but not posted. Their existence or absence should not be inferred.

Missing-data handling is not reported in the registry record. The posted information does not state whether all enrolled participants contributed data at every assessment, whether any outcome values were missing, or how missing observations were treated. A count of participants at risk does not by itself establish complete follow-up or complete outcome ascertainment. The record also does not give an analysis population definition, such as criteria for inclusion in a safety analysis.

These omissions matter because the meaning of a safety count depends on who was observed, how outcomes were collected, and how incomplete information was handled. The available record supports reporting the posted counts as descriptive figures, but not a conclusion about the completeness of follow-up, the effect of missing data, or the robustness of a statistical analysis.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: lumbar vertebral fracture (11.1%), abortion missed (11.1%), lumbar spinal stenosis (11.1%), wrist fracture (11.1%), cholestasis (11.1%).

The registry reports 2 participants affected in the serious-adverse-event count and 8 in the other-adverse-event count, with 9 at risk in the ALXN1007 group. It also records 0 deaths. These are separate registry summaries. The record does not explain whether participants could appear in both the serious and other-event counts, so the counts should not be added or treated as mutually exclusive categories.

The listed serious-event terms are Lumbar vertebral fracture, Abortion missed, Lumbar spinal stenosis, Wrist fracture, Cholestasis, and Liver Cytolysis; each is displayed as 11.1%. These are registry-reported values. The record does not provide event-level details or a comparative analysis that would establish whether an event was caused by ALXN1007. Nor does the list alone show how many participants experienced multiple listed terms.

Serious adverse events are safety observations, not automatically events caused by a treatment. In general, causal attribution requires clinical assessment and context beyond a count or event term. The registry record does not report attribution details for these events. The figures describe what was recorded, not a comparison with an untreated group or a conclusion about safety in a broader population.

13. What the Result Does, and Does Not, Mean

The result provides a descriptive record of adverse events among participants in an open-label, single-group study of intravenous ALXN1007. In the registry's group summary, 2 participants are affected in the serious-adverse-event count, 8 in the other-adverse-event count, and 0 deaths are recorded. The record also lists serious-event terms with displayed percentages. These observations characterize the posted safety data for the study group.

The figures do not establish that ALXN1007 caused the events. Without a concurrent comparator, the study cannot estimate how the event experience differed from that under another treatment or without the study intervention. The registry reports no inferential analyses, confidence intervals, or tests for the primary outcome. It therefore does not provide a statistical estimate of comparative safety or the precision of such an estimate.

The findings also do not establish efficacy. The primary purpose and outcome concern safety and tolerability; the posted record does not report an efficacy analysis. The data should not be taken as evidence that treatment works or does not work, or as a recommendation about treatment.

General limits of interpretation apply to descriptive findings from a small study: they may not characterize outcomes in a broader population, and uncommon events may not be well characterized. The record's termination status adds uncertainty about the circumstances of the study, because the reason for termination and its effect on data collection are not reported. The posted counts should be understood within the documented design and information, without extending them to claims the registry does not support.

14. Why This Trial Matters Statistically

This study matters statistically because its primary focus is safety and tolerability in a population described by persistent aPL positivity and specified non-criteria manifestations of antiphospholipid syndrome. Safety outcomes are often summarized descriptively, and participant counts can communicate what was recorded in a treated group. The registry provides such counts, along with listed serious-event terms and a death count.

At the same time, design determines what those numbers can answer. A single-group, open-label study can describe observed events in its group, but it does not provide a concurrent control for estimating a treatment contrast. The absence of a comparator is especially important when the outcome is adverse events, because observing an event during treatment does not by itself show that treatment caused it. The registry reports no inferential analyses that might otherwise quantify an association under a specified model.

The record also illustrates why outcome labels, measures, and analysis details should be read together. The primary outcome title refers to a percentage, while the posted measure is a participant count. The record does not report an analyzed percentage, uncertainty interval, or handling of missing outcomes. Those gaps limit precision and prevent readers from assessing the result as a comparative estimate.

Finally, the TERMINATED status is part of the study record but is not an explanation of the results. Without the reason for termination or information about data completeness, it should not be used to infer why the study ended or whether the posted safety summaries represent all planned observations. The statistical importance is therefore in distinguishing a descriptive safety account from evidence of a comparative treatment effect.

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.

The most direct limitation is the single-group design. There is no like-for-like control group, so the posted event counts cannot show how outcomes compare with another treatment or with no study intervention. Open-label status means masking was absent; the record does not report whether or how knowledge of treatment may have influenced event reporting or assessment.

The enrollment is 9, and the registry gives participant counts but no confidence intervals or inferential analyses. The precision of an event-frequency estimate is therefore not reported. The record does not describe how adverse events were defined, assessed, graded, or attributed, nor whether the serious and other-event summaries could include the same participants. It gives no event-level timing or recurrence information.

Important analysis details are not reported in the registry record: missing-data handling, analysis populations, a statistical analysis plan, sample-size justification, and interim analyses. The record also does not explain the relationship between the TERMINATED status and the completeness of outcome collection. No reason for termination is reported.

The primary outcome is titled as a percentage of patients reporting adverse events, but the posted measure is a participant count. No analyzed percentage or uncertainty estimate is reported. The listed serious-event terms and their displayed percentages do not resolve whether terms overlap within participants or provide a comparative assessment. These limitations confine interpretation to the recorded descriptive observations and prevent conclusions about causality, comparative safety, or efficacy.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Phase IIa Trial of ALXN1007 for the Treatment of Non-criteria Manifestations of Antiphospholipid Syndrome — NCT02128269.
• Registry record last updated 2017-07-13; status last verified 2017-06.
• Results first posted 2017-07-13.
• 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.

19. Record Summary

NCT02128269 is a Phase IIa, open-label, single-group study of intravenous ALXN1007 for persistently antiphospholipid-positive patients with at least 1 specified non-criteria manifestation of antiphospholipid syndrome. The registry records enrollment of 9, a study start of 2014-04, primary completion in 2016-06, and status TERMINATED. The primary outcome concerns safety and tolerability, measured as the percentage of patients reporting adverse events during Treatment Period (24 weeks).

The posted group summary reports 2 participants affected in the serious-adverse-event count, 8 in the other-adverse-event count, and 0 deaths. Serious-event terms are listed with displayed percentages. The registry reports no analyses and provides no comparator, inferential estimate, confidence interval, or statistical test. The reason for termination, missing-data handling, analysis populations, and analysis plan are not reported in the registry record. The results are descriptive safety observations and do not establish a comparative or causal treatment effect.