A Study of Aripiprazole Lauroxil (Also Known as ARISTADA TM) in Subjects With Schizophrenia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study of Aripiprazole Lauroxil (Also Known as ARISTADA TM) in Subjects With Schizophrenia (NCT02634320), a na phase 4 study. The primary outcome is Change From Baseline to Last Treatment Visit in Clinical Global Impressions-Severity (CGI-S) Scores.

2. Clinical Question

The registry record frames the study around safety and tolerability, while the primary endpoint is change in clinician-rated illness severity. CGI-S asks a clinician to rate how mentally ill a participant is at a specific point in time. The registry describes categories from normal, not at all ill, through among the most extremely ill patients. The reported endpoint is intended to summarize change between baseline and the last treatment visit, not to compare aripiprazole lauroxil with another treatment group.

The record does not report the observed mean change, its standard deviation, or an uncertainty interval. It therefore does not provide a numerical answer to the primary question. Secondary outcomes include change in Brief Psychiatric Rating Scale scores, adverse events, daily and social functioning, healthcare burden, and family burden. Their inclusion indicates additional domains of interest, but their results are not reported in the registry record.

3. Trial Design

This was a Phase 4, completed, single-group study sponsored by Alkermes, Inc. The registry lists 51 participants enrolled and identifies schizophrenia as the condition. The study began in 2015-12, and primary completion was recorded as 2017-07-11. The study intervention was aripiprazole lauroxil, given as an intramuscular injection.

The official title describes subjects inadequately treated with paliperidone palmitate or risperidone long-acting injection. The design does not include a separate control arm: allocation is listed as NA, masking as none, and the model as single-group. Consequently, any baseline-to-last-visit change is a within-group description. It does not estimate a randomized treatment contrast or distinguish the intervention’s contribution from other influences on change over time.

The primary outcome is change from baseline to the last treatment visit in CGI-S scores, with a timeframe of up to 7 months. The record describes the endpoint as a mean and identifies standard deviation as its dispersion measure. The primary endpoint description specifies a safety population of subjects who received at least 1 dose and had a last on-treatment visit. The number meeting that definition is not reported in the registry record, so it cannot be assumed to equal the enrolled count.

The record also lists secondary measures covering psychiatric symptoms, adverse events, daily and social functioning, healthcare services, and family burden. Detailed protocol information about treatment procedures beyond intramuscular administration, visit schedules, or the rationale for the design is not reported in the registry record. Sample-size justification, interim analyses, and a full statistical analysis plan are also not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: All subjects received 4 to 6 doses of aripiprazole lauroxil in monthly or 6-week intervals.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Safety population includes all subjects who received at least 1 dose of study drug and had a last on-treatment visit.

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 included all subjects who received at least one dose of study drug. All analyses were performed on the Safety population.

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline to Last Treatment Visit in Clinical Global Impressions-Severity (CGI-S) Scores, measured over Up to 7 months.

The primary endpoint is change from baseline to the last treatment visit in Clinical Global Impressions-Severity (CGI-S) score, assessed over up to 7 months. CGI-S is a clinician-rated measure of how mentally ill a participant is at a specific point in time. Its categories range from “1: normal, not at all ill” to “7: among the most extremely ill patients,” with intermediate categories describing increasing severity.

A change score describes the difference between a participant’s assessment at baseline and the assessment at the last treatment visit. A group mean can summarize the direction and average size of those changes, while a standard deviation describes how dispersed individual changes are around that mean. These are general interpretations of the chosen summary measures; the registry record does not report the observed mean change or standard deviation.

Clinician-rated severity is used to represent a broad judgment of illness severity rather than a single symptom or functional domain. Its usefulness depends on how consistently assessments are made and on the completeness of the observations. The registry record does not report further details about assessor training, reliability procedures, or handling of participants without a last on-treatment assessment. Without the endpoint estimate and its uncertainty, the record does not show the magnitude or precision of change on CGI-S.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change represent?

For a continuous outcome such as CGI-S, a mean change is a group-level summary of individual changes between baseline and the last treatment visit. It condenses many participant observations into one measure. The direction of a change must be interpreted using the scale’s meaning, and the mean alone does not show whether changes were similar across participants or concentrated in a subset. In this study, the registry record identifies a mean as the primary summary, but does not report its value.

What does the standard deviation describe?

The standard deviation describes the spread of participant values around a mean. A smaller spread indicates that observed values lie more closely together; a larger spread indicates greater variability. It is not the same as the uncertainty in the estimated mean. The standard deviation of the primary endpoint is not reported in the registry record, so the observed variability cannot be described.

How should a confidence interval be read?

In general, a confidence interval gives a range of values compatible with the data and the statistical procedure used, and it communicates estimation uncertainty. Its width is influenced by variability and the amount of information available. An interval that is narrow indicates greater precision than a wide interval, but neither width nor the interval’s position establishes causality. The registry record does not report a confidence interval for the primary endpoint.

What can a single-group change estimate show?

A within-group estimate can describe the observed course between baseline and follow-up among participants whose data are analyzed. It does not compare that course with what would have happened under another treatment or no study intervention. A randomized comparator can help address differences between treatment groups, while this study’s single-group design does not provide that contrast. This is a general limitation of interpreting within-group change, not a claim about the direction of the unreported result.

Why does the analysis population matter?

The primary endpoint description specifies a safety population consisting of participants who received at least 1 dose and had a last on-treatment visit. The enrolled count is 51, but the number meeting the population definition and the number with complete CGI-S observations are not reported in the registry record. If participants without follow-up assessments are excluded, the analyzed group may differ from the enrolled group. General statistical interpretation therefore depends on knowing who contributed outcome data and how missing observations were handled.

What does over-dispersion mean in general?

Over-dispersion occurs when observed variability exceeds what a statistical model assumes. It can make standard errors too small and intervals or tests too optimistic if the model does not account for the extra variation. The relevance of over-dispersion depends on the outcome and analysis model. The registry record does not report an analysis model for the primary endpoint, so it is not possible to say whether over-dispersion was assessed or relevant in this analysis.

What can the adverse-event counts establish?

Counts describe how many participants were recorded with events in the study group. They are useful for characterizing what was observed, but a count alone does not estimate a comparative risk or establish causation. A comparison would require an appropriate reference group and compatible ascertainment. This study has no separate control group, and the registry record does not report a comparative safety analysis. It also does not give confidence intervals for the listed counts.

Were particular statistical procedures used?

The registry record identifies the primary endpoint’s summary as a mean and its dispersion as a standard deviation. It does not report the test procedure, model, adjustment variables, assumptions, or method for addressing repeated measurements. The study’s protocol-level statistical analysis plan is not reported in the registry record. General descriptions of means, standard deviations, confidence intervals, and model assumptions explain statistical concepts; they should not be mistaken for procedures confirmed as used in this trial.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Aripiprazole Lauroxil")
n   <- c(49)
m   <- c(-0.2)
sp  <- c(0.87)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Aripiprazole Lauroxil  49  -0.200  0.870  -0.450  0.050

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists a primary endpoint and several secondary outcomes, but does not report whether or how the statistical analysis accounted for multiplicity. Multiplicity arises when several outcomes or tests are considered: the more opportunities there are to identify a result by chance, the more important it is to understand any prespecified testing strategy. No adjustment method, hierarchy among secondary outcomes, or confirmatory testing sequence is reported in the registry record. The listed outcomes should therefore not be treated as a documented set of statistically controlled tests.

Missing-data methods are also not reported in the registry record. The primary endpoint description defines the safety population as subjects who received at least 1 dose and had a last on-treatment visit. That definition describes eligibility for the population but does not explain how missing baseline or follow-up scores were handled, whether any imputation was used, or how participants without a last visit were treated. The number with complete endpoint data is not reported.

These details affect interpretation. If follow-up data are unavailable for some participants, the observed mean change may describe only those with usable measurements. Whether that subset represents the enrolled group depends on why data are missing and on the analysis approach. The registry record does not provide information to evaluate those conditions.

The record also does not report the analysis population for each secondary outcome or explain whether safety and clinical outcomes used different inclusion rules. Consequently, the enrolled count of 51 should not automatically be treated as the denominator for every outcome. The population definition and the missing-data approach are essential context for reading any outcome estimate, but remain unreported for the primary analysis beyond the stated safety-population definition.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: psychotic disorder (3.9%), suicidal ideation (3.9%), chronic obstructive pulmonary disease (2.0%).

The registry record lists 51 participants at risk for serious adverse events and 5 affected, alongside 51 at risk for other adverse events and 3 affected. It reports 0 deaths. These are counts for the single study group; they are not comparative estimates against a control group. The record lists psychotic disorder and suicidal ideation at 3.9% each, and chronic obstructive pulmonary disease at 2.0%, among the top serious adverse-event terms.

These figures describe events recorded during the study and do not by themselves show whether an event was caused by aripiprazole lauroxil. Serious adverse events and other adverse events are presented as separate categories in the registry record; it does not report whether the participants in those categories overlap. The percentages attached to the serious-event terms are reproduced as listed and should not be interpreted as treatment-attributable risks.

Without a comparator group, uncertainty intervals, or further event detail, the counts cannot establish comparative safety or explain event timing and outcomes. The record does not report additional information about event severity beyond the serious-event classification, duration, or relatedness assessment.

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

The registry record describes a completed single-group Phase 4 study of intramuscular aripiprazole lauroxil in subjects with schizophrenia inadequately treated with paliperidone palmitate or risperidone long-acting injection. It specifies a primary measure of change in CGI-S from baseline to the last treatment visit, up to 7 months, and lists several secondary domains. These details explain what the study set out to assess.

The record does not report the primary endpoint estimate or its uncertainty. It therefore does not establish the size, direction, or precision of any change in clinician-rated severity. The absence of a reported result in the registry record is not evidence that there was no change; it means the posted record does not provide the information needed to characterize that endpoint.

The design also limits what a change score could mean. With no separate comparator, an observed before-and-after difference would not isolate the effect of the study intervention from other explanations for change over time. In general, a controlled comparison can provide context for interpreting an outcome; this single-group record does not provide one.

The safety counts describe reported events among participants at risk, including 5 with serious adverse events, 3 with other adverse events, and 0 deaths. They do not establish that the intervention caused or prevented any event. A comparator and additional details would be needed for a more direct comparative interpretation.

Accordingly, the registry record supports a description of the study design, selected outcome measures, and listed safety observations. It does not support a numerical conclusion about the primary outcome’s magnitude or precision, a causal conclusion about changes over time, or a comparative conclusion about safety. Statistical interpretation should remain within those limits.

14. Why This Trial Matters Statistically

This study is statistically informative as an example of how a clearly named outcome and a defined analysis population still leave important questions when results are not reported. The primary endpoint identifies a clinician-rated severity measure, a baseline-to-last-visit comparison, a mean summary, and standard deviation as its dispersion measure. Those specifications help readers understand the intended measurement, but they do not substitute for the estimate, variability, or uncertainty interval.

The single-group design is also important. A change over time may be useful for describing participants’ observed course, but without a separate comparator it cannot distinguish intervention-related change from other influences. This distinction is central to interpreting nonrandomized, within-group evidence. The registry record makes the study structure clear through its single-group designation and lack of allocation, so the limits of causal interpretation are visible.

The population definition highlights a further issue: 51 participants were enrolled, while the primary endpoint applies to subjects who received at least 1 dose and had a last on-treatment visit. The size of that defined population and the number with evaluable measurements are not reported in the registry record. That gap matters because the denominator and missing observations affect how representative an outcome summary may be.

The safety listing offers counts and named serious-event terms, but no comparison group or uncertainty intervals. It can characterize what the registry records, not establish causation or relative risk. Taken together, the record illustrates why design, analysis population, outcome estimates, uncertainty, and missing-data handling must be considered together when interpreting clinical trial statistics.

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.

A central limitation is that the primary endpoint result is not reported in the registry record. The mean change in CGI-S, its standard deviation, and any confidence interval or test result are absent. This prevents assessment of the observed magnitude, direction, variability, and precision of the primary outcome.

The single-group design has no separate comparator, so within-group change cannot serve as a randomized treatment contrast. The record lists allocation as NA and masking as none. It does not report a protocol rationale for these design choices, and no such rationale can be inferred from the registry entry.

Although 51 participants were enrolled, the primary endpoint’s safety-population definition requires receipt of at least 1 dose and a last on-treatment visit. The number meeting that definition is not reported in the registry record. The number with complete CGI-S observations, reasons for missing assessments, and methods for handling missing data are also not reported.

The registry record does not report the statistical analysis plan, model details, adjustment procedures, sample-size justification, or interim analyses. It also does not describe assessor training or reliability procedures for CGI-S. These omissions limit evaluation of the analysis and measurement process.

Safety interpretation is limited by the lack of a comparator and by the absence of reported uncertainty intervals or additional event details. The registry record does not state whether participants with serious and other adverse events overlap. The listed counts and terms should therefore be read as descriptive study observations, not as comparative or causal estimates.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study of Aripiprazole Lauroxil (Also Known as ARISTADA TM) in Subjects With Schizophrenia — NCT02634320.
• Registry record last updated 2018-12-04; status last verified 2018-11.
• Results first posted 2018-11-08.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT02634320 is a completed Phase 4, single-group study sponsored by Alkermes, Inc., with 51 participants enrolled. It evaluated intramuscular aripiprazole lauroxil in subjects with schizophrenia inadequately treated with paliperidone palmitate or risperidone long-acting injection. The study began in 2015-12, with primary completion recorded as 2017-07-11.

The primary endpoint was change from baseline to the last treatment visit in CGI-S score over up to 7 months, summarized as a mean with standard deviation. The registry record does not report the observed primary endpoint result. It lists 5 participants with serious adverse events and 3 with other adverse events among 51 at risk, with 0 deaths. No separate comparator group was included, so the record does not provide a comparative treatment estimate.