Aripiprazole, Abilify Maintena Collaborative Clinical Protocol: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Aripiprazole, Abilify Maintena Collaborative Clinical Protocol (NCT02472652), a na phase 4 study. The primary outcome is Change in Arizona Sexual Experiences Scale (ASEX) Score.

2. Clinical Question

3. Trial Design

This was a Phase 4, open-label, single-group study, with allocation recorded as not applicable and masking recorded as none. It was sponsored by Gazda, Thomas D., M.D., PC. The registry lists an enrollment of 2 and a terminated status. The recorded start was 2015-06, and primary completion was 2016-12-31.

Participants were to switch from Invega Sustenna or Risperdal Consta to Abilify Maintena and have sexual functioning reassessed over a 3 month period. The described monthly doses were 400mg, 300mg, 200mg or 160mg. The primary outcome was change in ASEX score from baseline to endpoint, with the timeframe stated as baseline and 12 weeks. The outcome description says participants would be followed for an average of about 5 months; that is a description of follow-up, not a reported outcome time for every participant.

The design is within-group: it can describe measurements before and after the switch among participants with available data, but it does not directly compare the switch with continued use of either prior medication or another treatment. Open-label means the study was not masked. The registry record does not report a detailed protocol rationale for the design, a sample-size justification, or further information about how treatment dose was selected for each participant. Because enrollment was 2 and data were unavailable for Subject 2, interpretation of the posted outcome is especially constrained. The registry record does not report the primary endpoint estimate, making it impossible to characterize the observed change statistically.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Data no available for Subject 2 as lost to 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 Change in Arizona Sexual Experiences Scale (ASEX) Score, measured over Baseline and 12 weeks.

The primary endpoint is change in Arizona Sexual Experiences Scale (ASEX) score from baseline to endpoint, with the timeframe specified as baseline and 12 weeks. ASEX is described as a self-rated 5 item measure of sexual functioning. Total scores range from 5 - 30, and higher scores indicate more sexual dysfunction. The registry description says the scale was used at screening to assess whether participants met the study criteria and to establish a baseline for assessing change.

A change score is intended to capture how a participant's measured status differs between the stated time points. In general, repeated measurement can describe change within the same participant, but without a concurrent comparator it cannot separate an effect associated with the switch from changes that might occur for other reasons. The registry description refers to significant improvement as a study aim, but does not report an observed score change, a measure of variability, or an inferential result for the primary endpoint. Therefore, the endpoint's scale and intended timing are described, but the posted record does not allow readers to judge the magnitude or precision of any change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies a single-group study and gives the primary outcome as change in ASEX score. That structure matters when interpreting statistical methods. In a randomized comparison, an analysis can estimate a contrast between groups assigned to different strategies. Here, there was no randomized comparison and no concurrent control group. The central outcome is therefore a before-and-after measurement in participants who switched treatment, rather than a randomized treatment contrast.

What a change score represents

In general, a change score compares a participant's measurement at a later time with that participant's measurement at baseline. For this study, the named time points are baseline and 12 weeks. The registry record does not report the individual scores, the change estimate, or an estimate of variation among participants. It is therefore not possible to verify how the reported analysis handled the available measurements or to judge the magnitude of change from the record.

When change is measured on a numeric scale, an average change can summarize the direction and typical size of changes in a group. Its interpretation depends on the scale, the participants included, and the analysis approach. In a small single-group study, the estimate would be highly dependent on the few observed participants. A missing outcome for Subject 2 further limits what can be learned from the enrolled group. These are general statistical considerations; they do not establish the value or direction of the unreported ASEX result.

Why a comparator matters

In general, a concurrent comparator provides a reference for changes that might occur over time even without the intervention of interest. Without one, a change after switching cannot be attributed uniquely to the switch. Other influences, including changes in circumstances or measurement, may coincide with the follow-up period. The registry record does not report a design feature that could resolve this limitation. The prior medications identify the clinical context for enrollment, but they do not serve as an observed control group in the listed design.

Precision and uncertainty

In general, a confidence interval communicates uncertainty around an estimate. A narrower interval indicates greater precision under the assumptions of the analysis; a wider interval indicates less precision. A p-value, when reported, addresses how compatible the observed data are with a specified null hypothesis under a statistical model. Neither replaces consideration of the estimate's size, uncertainty, design, or missing data. The registry record does not report a confidence interval or p-value for the primary endpoint. No inference about statistical significance or precision can be made from the endpoint description alone.

Small samples generally make estimates sensitive to individual observations. That is particularly relevant when the total enrollment is 2 and the registry notes missing outcome data for one participant. It does not license calculation of an estimate from enrollment counts; the participant-level scores and analysis results are not reported. In general, a model cannot compensate for the absence of outcome information without assumptions about the missingness and a stated analytic approach.

Planning calculations are not trial results

In general, sample-size planning asks how many participants might be needed to detect a specified effect under chosen assumptions. Such an illustration is not an observed study result and is not observed power. The stated planning assumptions for this record use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the target effect is expressed as a fraction of the observed effect. Those hypothetical assumptions do not describe this study's single-group design, and they should not be read as its actual design or as evidence that the study achieved a particular power. The registry record does not report the study's own sample-size justification.

General planning calculations also depend on the effect size chosen and on the analysis assumptions. If the observed effect used as a reference is not reported, the planning values cannot be interpreted independently as evidence about the clinical result. Any planning figures should be treated as illustrations of assumptions rather than estimates of what the study observed. They do not overcome the lack of a reported primary outcome result.

Outcome types and distribution

The primary outcome is a score, while the record's outcome classification is count/other. That classification does not, by itself, disclose the statistical model or test used. The registry lists one analysis, but the method, test statistic, model assumptions, and handling of repeated measurements are not reported in the registry record. It would be inappropriate to infer a particular parametric test, nonparametric test, or model from the outcome title alone.

In general, over-dispersion means that variation in count data exceeds what a simple model assumes. It can affect standard errors and inferential conclusions when a count model is used. The primary endpoint is described as a scale score, and the record does not report an over-dispersion analysis or a count model. This general concept should not be mistaken for a method known to have been used in this study.

Overall, the registry supports a description of the study design, the intended endpoint, and the available safety counts. It does not support reconstructing the primary statistical analysis or its result. The analysis method, treatment of missing data, population used for analysis, and uncertainty around the primary outcome are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 2 outcome measures: the primary ASEX change and a secondary outcome of prolactin concentrations. It also lists one analysis. The record does not report whether statistical tests were planned for both outcomes, whether additional time points or subgroups were considered, or whether any adjustment for multiple testing was used. When multiple outcomes or comparisons are tested, the chance of finding an apparently notable result by chance can increase; in general, multiplicity procedures are used to address that issue. No particular procedure can be attributed to this study from the registry record.

Missing outcome data are directly relevant. The primary outcome description states that data were unavailable for Subject 2 because of loss to follow-up. The registry record does not report the reason for loss to follow-up, whether the participant had any partial measurements, or whether a missing-data method was used. It also does not identify the analysis population or say whether analyses included all enrolled participants or only those with available outcome data.

In general, complete-case analysis uses participants with observed data for the outcome being analyzed, while other approaches require assumptions about how data became missing. These approaches can yield different interpretations, especially when the sample is limited. No method should be assumed. The registry record does not report an imputation approach, sensitivity analysis, or assessment of the missingness mechanism. As a result, the effect of the unavailable data on the primary outcome cannot be evaluated. The same limitation applies to the secondary outcome because its numerical results and missingness details are not reported.

11. 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: hospitalization (50.0%).

The registry safety record lists 2 participants at risk for serious adverse events and 1 participant with a serious adverse event. It lists 2 participants at risk for other adverse events and 1 participant with an other adverse event. The reported serious-event term is hospitalization, listed at 50.0%. The death count is 0.

These counts describe what the registry reports for this small study; they do not establish a comparative risk because there is no concurrent control group. The percentage should be read as a description of the recorded study group, not as a reliable estimate for a broader population. With 2 participants at risk, an event affecting one participant has substantial influence on the reported proportion. The registry record does not provide event timing, duration, relatedness to treatment, severity details beyond the serious-event classification, or a narrative explaining the hospitalization. It also does not report whether events occurred in the same participant. The safety figures therefore support a limited account of the recorded events, not a causal conclusion about treatment or a general safety rate.

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

The study asked whether sexual functioning, measured with ASEX, changed after participants switched from Invega Sustenna or Risperdal Consta to Abilify Maintena. The registry gives the intended baseline-to-12-week endpoint and describes the intervention, but does not report the observed primary outcome result. Consequently, the posted record does not establish whether ASEX scores increased, decreased, or remained similar, nor how precisely any change was estimated.

The study's single-group, open-label design would limit causal interpretation even if a before-and-after result were available. A measured change could describe participants' experience over the follow-up period, but the design has no concurrent comparison with continued prior treatment or another strategy. The study's enrollment of 2 and the missing primary outcome data for Subject 2 further constrain interpretation. The registry record does not report the primary analysis population or a method for addressing that missing outcome.

The record's safety counts indicate one serious adverse event, one other adverse event, and 0 deaths among the participants at risk, with hospitalization identified as the serious-event term. These counts are descriptive and do not establish that the intervention caused an event or that the intervention's safety profile is characterized for a larger group.

Thus, the registry record documents a small terminated study and its intended clinical question, rather than a sufficiently reported estimate of treatment-associated change. It does not show that switching improved sexual functioning, and it also does not show that switching failed to do so. The distinction is important: an unreported result cannot be interpreted as a null result. The available information supports conclusions about the design and reporting limitations, not about the size or existence of an effect.

13. Why This Trial Matters Statistically

This trial matters statistically because the clinical question is framed around a patient-reported outcome and a treatment switch, while the design includes no concurrent comparator. That combination makes it important to distinguish measured change over time from an effect attributable to the switch. A before-and-after outcome can describe what happened among participants with data, but causal interpretation requires more than a change in scores.

The study also illustrates how enrollment and missingness affect the evidence that can be extracted from a registry. Enrollment was 2, and the primary outcome description says data were unavailable for Subject 2 because of loss to follow-up. With so little outcome information, individual observations and missing data are central rather than incidental considerations. Yet the registry record does not report the observed ASEX result, an analysis population, a missing-data method, or an uncertainty estimate.

Another statistical point is the difference between study design and hypothetical planning assumptions. The registry describes a single group, while the planning assumptions refer to equal allocation between two arms. Those assumptions belong to a planning illustration, not the actual design. Keeping that distinction clear prevents planning calculations from being mistaken for trial results or observed power.

Finally, the record demonstrates why outcome definitions, estimates, and uncertainty all matter. A stated endpoint establishes what investigators intended to measure; it does not convey what was observed. Without numerical outcome results, readers cannot assess the size, direction, or precision of the primary finding. The statistical importance of the record lies in these limits on interpretation, not in an outcome conclusion 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.

Several limitations specific to this study constrain interpretation. It was an open-label, single-group study with no concurrent comparator, so a before-and-after change could not be separated from other changes over time. The registry lists 2 participants enrolled and states that data for Subject 2 were unavailable because of loss to follow-up. It does not report the primary endpoint result, the individual data, or an uncertainty estimate.

The registry record does not explain why the study was terminated, how the dose among the listed monthly options was selected, or whether the planned follow-up was completed. Although the outcome description refers to an average follow-up of about 5 months and the primary timeframe is baseline and 12 weeks, it does not give participant-level follow-up information. The record does not report the statistical method, analysis population, missing-data approach, multiplicity procedure, or a detailed statistical plan.

The participant eligibility description relies in part on recalled change since starting prior medication, and the primary measure is self-rated. These features describe how the study framed eligibility and measurement; the record does not quantify their effect on results. The registry does not report prolactin outcome values, despite listing them as a secondary outcome. Safety details are also limited to counts and a serious-event term, without event narratives or timing. Collectively, these gaps prevent assessment of the primary result, its robustness, and the broader applicability of the findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Aripiprazole, Abilify Maintena Collaborative Clinical Protocol — NCT02472652.
• Registry record last updated 2019-04-11; status last verified 2019-03.
• Results first posted 2019-04-11.
• 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.

18. Record Summary

NCT02472652 is a Phase 4, open-label, single-group study of switching to Abilify Maintena among participants reporting worsening sexual dysfunction while receiving Invega Sustenna or Risperdal Consta. The registry lists enrollment of 2 and a terminated status. The primary outcome is change in ASEX score from baseline to 12 weeks; higher scores indicate more sexual dysfunction.

The registry record does not report the numerical primary outcome result or its precision. It states that data for Subject 2 were unavailable because of loss to follow-up. Prolactin concentrations are listed as a secondary outcome, but numerical secondary results are not reported in the record details. The safety record lists one serious adverse event, one other adverse event, hospitalization as the serious-event term at 50.0%, and 0 deaths. The small enrollment, missing outcome information, single-group design, and absent outcome estimate limit interpretation.