Brexpiprazole as Adjunctive Therapy With Major Depressive Disorder and an Inadequate Response to Previous Adjunctive Therapy: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Brexpiprazole as Adjunctive Therapy With Major Depressive Disorder and an Inadequate Response to Previous Adjunctive Therapy (NCT02012218), a na phase 3 study. The primary outcome is Mean Change From Baseline to Week 6 in Montgomery-Asberg Depression Rating Scale (MADRS) Total Score.

2. Clinical Question

The clinical question is exploratory: it concerns the course of depression-rating scores after a switch to adjunctive brexpiprazole in a population described as having responded inadequately to previous adjunctive therapy. It is not a randomized test of brexpiprazole against continued previous therapy, placebo, or another treatment. Without a comparison group, changes over time cannot be separated from other influences, including the natural course of symptoms, expectations associated with an open-label study, or changes in concurrent care.

The primary outcome was measured using the Montgomery-Asberg Depression Rating Scale (MADRS), with assessments at baseline and Week 6. The endpoint is a mean change, rather than an individual participant’s response category or a comparison of the proportion meeting a threshold. The posted registry record does not provide the estimate, its standard error, a confidence interval, or a test result. It therefore does not answer the numerical part of the question about the observed mean change or its precision.

3. Trial Design

This completed Phase 3b exploratory trial studied brexpiprazole as adjunctive therapy in adults with MDD and an inadequate response to previous adjunctive therapy. The official title describes it as a multicenter, open-label trial. The registry record lists a single-group model, no masking, and allocation as not applicable. Enrollment was 61. The record lists the start as 2013-11 and primary completion as 2014-10.

The intervention is described as ADT and brexpiprazole. The trial objective was to evaluate efficacy, safety, and subject satisfaction after switching to adjunctive brexpiprazole. The registry record does not describe a randomized control arm, a blinded assessment process, or a comparator treatment. Consequently, the study is not a like-for-like comparison between treatments. Its single-group structure can describe outcomes among participants assessed during the trial, but by itself cannot identify how outcomes would have differed under another treatment or without the switch.

The primary endpoint was mean change from baseline to Week 6 in MADRS total score. The listed analysis parameter is a least-squares mean, with standard error as the dispersion measure. The endpoint population is defined as participants who took at least one dose of brexpiprazole and had a valid baseline and at least one valid post-baseline efficacy assessment. The record does not report the number in that analysis population.

The registry record identifies the study as completed, but completion status does not indicate whether every planned analysis or outcome is available in the posted results. The record gives no numerical primary outcome estimate, no detailed statistical analysis plan, and no explanation of the group labels used in the adverse-event information. Details such as dose, adherence, and the specific previous adjunctive therapies are 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: The trial consisted of a continuous 6-week open-label treatment period including an initial 2-week titration period with a 30-day (+2 days) follow-up period.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All participants who took at least one dose of brexpiprazole and who had a valid baseline assessment and at least one valid post-baseline efficacy assessment.

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 Mean Change From Baseline to Week 6 in Montgomery-Asberg Depression Rating Scale (MADRS) Total Score, measured over Baseline and Week 6.

The primary endpoint is the mean change in MADRS total score from baseline to Week 6. MADRS is a clinician-administered measure of depression severity. The registry description says it was administered using the Structured Interview Guide for the MADRS and that detailed instructions were provided. Its 10 items each have 7 defined grades of severity, from 0, the “best” rating, to 6, the “worst” rating. The total is the sum of item ratings, with possible scores ranging from 0 to 60.

A change score expresses how the average rating at follow-up differs from the baseline rating. The endpoint is reported as a least-squares mean, which is a model-based mean; the registry record does not specify the model or its covariates. The listed measure of dispersion is the standard error, which describes the estimated precision of the mean, rather than the spread of individual scores.

MADRS is used to quantify depressive symptom severity on a consistent scale at two time points. A mean change can describe the average direction and size of score movement in the analyzed population, but it does not show how every participant changed or whether an individual met a particular threshold. The registry record does not report the numerical mean change or standard error, so the endpoint’s observed magnitude and precision cannot be assessed from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The record identifies a continuous primary outcome: mean change in MADRS total score from baseline to Week 6. It specifies a least-squares mean as the analysis parameter and a standard error as the dispersion measure. It does not report the numerical estimate or explain the statistical model used to obtain it. The concepts below are general explanations of the measures named in the registry record, not claims about unreported analyses in this trial.

What does a least-squares mean represent?

General explanation: an ordinary mean is calculated directly from the observed values in a group. A least-squares mean is generally an estimate from a statistical model, sometimes adjusted for factors included in that model. The model and included factors affect how the estimate should be interpreted. Since the registry record does not describe the model or any adjustment variables, the precise basis of this least-squares mean is not reported in the registry record.

In this study, the named quantity is the average change in MADRS total score over the stated assessment period. The record does not provide that change’s numerical value. It therefore cannot establish whether the estimated average change was positive or negative or how large it was.

What does the standard error describe?

General explanation: a standard error describes the uncertainty of an estimated quantity, such as a mean. It is not the same as the standard deviation, which describes variation among individual observations. A smaller standard error generally indicates a more precise estimate, while a larger one indicates greater uncertainty, given the statistical model and data. The registry record names the standard error as the dispersion measure but does not post its value.

How does a confidence interval help?

General explanation: a confidence interval gives a range of values compatible with the observed data under a specified statistical procedure. It communicates precision and helps readers judge which effect sizes remain plausible. A confidence interval for the primary mean change is not reported in the registry record. Without the estimate and its interval, the extent of uncertainty around the primary endpoint cannot be evaluated from this record.

What can a baseline-to-follow-up analysis show?

General explanation: measuring participants at baseline and follow-up can describe within-group change over time. It does not, without a suitable comparison, separate a treatment effect from other causes of change. This distinction is especially important for an open-label, single-group study: there is no randomized comparator to represent what would have happened over the same period under another condition.

The primary endpoint population also matters. The record defines it as participants who took at least one dose of brexpiprazole and had both a valid baseline assessment and at least one valid post-baseline efficacy assessment. This is a description of who was eligible for the primary efficacy analysis, not the number analyzed. That number is not reported in the registry record. The record also does not state how many participants lacked follow-up assessments or how missing scores were handled.

How should the safety counts be read?

General explanation: counts of participants affected by adverse events describe the safety experience recorded for a group, while serious adverse events are a subset distinguished by seriousness criteria. Such counts are descriptive; comparisons of risk require suitable denominators and, for causal comparisons, an appropriate control design. The registry record lists counts at risk and counts affected by serious and other adverse events for several labeled groups. It does not explain those group labels or provide a randomized comparison. The listed figures therefore should not be treated as evidence that one treatment or group is safer than another.

Sample-size calculations, when presented as planning illustrations, answer a different question from the trial’s observed outcome. General explanation: they illustrate the number of participants per arm that a hypothetical future study might need under stated assumptions, such as a target effect and significance level. They are not observed results and are not observed power. The record characterizes its sample-size assumptions as a planning illustration based on the observed effect, with equal allocation and a normal approximation. The numerical planning outputs are not included in this discussion, and they should not be confused with the missing primary estimate or with the trial’s enrollment.

The record does not report whether interim analyses were conducted, whether multiplicity was addressed, which covariates were included in the model, or what detailed statistical analysis plan was used. Those methods cannot be inferred from the endpoint label or from the fact that the study is completed.

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("Group 1A", "Group 1B", "Group 2", "Group 3", "Group 4")
n   <- c(12, 10, 12, 19, 6)
m   <- c(-12.8, -18.4, -19.5, -19.2, -16.8)
sp  <- c(2.26, 2.1, 1.99, 1.59, 2.97)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
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  Group 1A  12  -12.800  7.829  -17.774  -7.826
CARM  Group 1B  10  -18.400  6.641  -23.151  -13.649
CARM  Group 2  12  -19.500  6.894  -23.880  -15.120
CARM  Group 3  19  -19.200  6.931  -22.540  -15.860
CARM  Group 4  6  -16.800  7.275  -24.435  -9.165

11. Multiplicity, Missing Data and Analysis Populations

The registry record reports one primary outcome measure and one analysis. It does not report a statistical plan for handling multiple tests or outcomes, nor does it say whether any adjustment for multiplicity was used. The number of listed outcomes alone does not establish how all analyses were prioritized or whether other analyses were conducted.

The primary efficacy population is defined as participants who took at least one dose of brexpiprazole and had a valid baseline assessment and at least one valid post-baseline efficacy assessment. The record does not report the number who met this definition, the number excluded, or reasons for exclusion. It also does not describe whether the analysis followed an intention-to-treat principle or another prespecified population definition.

Missing-data handling is not reported in the registry record. In particular, the record does not state how participants without a Week 6 assessment were handled, whether any imputation method was used, or what assumptions were made about missing outcomes. These details can affect a mean-change estimate, so the population definition alone is not enough to assess potential bias from missing data.

The specific statistical model, covariates, and any sensitivity analyses are also not reported in the registry record. The outcome is labeled as a least-squares mean, but that label does not reveal the model specification. No numerical primary result is posted, making it impossible to assess how alternative missing-data or analysis choices might have affected the estimate.

12. Safety Results

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

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: rhabdomyolysis (9.1%).

The safety information is organized under Group 1A, Group 1B, Group 2, Group 3, and Group 4. For each group, the registry record gives a number at risk and counts affected by serious and other adverse events. It reports zero serious events for Group 1A, Group 2, Group 3, and Group 4, and one for Group 1B. Counts affected by other adverse events are listed as seven, eight, six, 15, and five, respectively, in the order of the groups above.

The record does not explain what the group labels mean or whether they represent different treatment exposures or other categories. They should not be read as randomized treatment arms or as a direct comparison. The record lists rhabdomyolysis at 9.1% among the top serious terms. It does not provide further context about the term’s group attribution in the posted information.

Deaths are not reported in the registry record; the death entries are null, which should not be interpreted as a reported count of zero. More generally, these figures are descriptive safety data. They do not establish comparative risk, and the record does not provide enough context to determine how the group definitions relate to the study’s overall intervention.

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

The record documents an exploratory, open-label, single-group study of adjunctive brexpiprazole in adults with MDD and an inadequate response to previous adjunctive therapy. It defines the primary measure as least-squares mean change in MADRS total score from baseline to Week 6. That information clarifies what the efficacy endpoint was intended to capture and which participants qualified for the stated analysis population.

However, the numerical primary endpoint result is not reported in the registry record. The average change, standard error, confidence interval, and p-value are absent. Thus, the record does not show the direction or size of the average score change, nor how precisely it was estimated. A stated endpoint is not itself evidence of an observed outcome.

Even a numerical before-and-after result from this design would describe change in the study group, rather than establish that brexpiprazole caused the change. General explanation: a randomized comparison helps distinguish an intervention’s effect from changes that might have occurred over time for other reasons. This study is recorded as single-group and open-label, with no randomized comparator. It therefore cannot supply that controlled contrast.

The safety figures offer descriptive counts for groups whose labels are not explained in the record. They do not establish comparative safety or allow a clear interpretation of differences among the groups. The listed serious-event term is also not enough by itself to characterize the overall safety profile.

In short, the record supports understanding the trial’s intent, design, endpoint definition, and selected safety entries. It does not support a quantitative conclusion about the primary efficacy result, and it does not provide a controlled estimate of treatment effect. Those limits should remain central when interpreting the posted information.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of the difference between a clearly defined endpoint and a reported result. The registry record specifies a Week 6 mean change in MADRS total score, a least-squares mean analysis parameter, a standard error, and a defined primary efficacy population. Yet it does not report the estimate or its uncertainty. Without those values, readers cannot assess the observed change or its precision.

The single-group, open-label design is also important. It can describe outcomes during treatment, but it does not provide a randomized comparison to separate intervention-related change from other influences. This is not a minor technical detail: it determines what causal question the study can answer. The trial’s exploratory purpose and stated evaluation of efficacy, safety, and satisfaction do not substitute for a comparator.

The safety entries illustrate another interpretive issue. Group-specific counts may look comparable, but the registry record does not define the groups. Without that context, the figures cannot be treated as contrasts between treatments. Missing detail about the efficacy analysis population and missing-data methods also limits assessment of how the analysis relates to all enrolled participants.

For biostatistical reading, the record therefore underscores the value of reporting estimates with uncertainty, identifying analysis populations, describing missing-data procedures, and defining safety categories. It also shows why design features must be considered alongside any outcome: a within-group mean change and a randomized treatment contrast answer different questions.

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 consequential limitation of the posted record is that it does not report the numerical primary efficacy result. The least-squares mean change in MADRS total score, its standard error, any confidence interval, and any p-value are not reported in the registry record. The endpoint is described, but its observed magnitude and precision cannot be evaluated.

The study is recorded as open-label and single-group, with allocation listed as not applicable. There is no randomized comparator, so the design cannot establish a treatment effect relative to another condition. The record does not report additional design details that might clarify how assessments were protected from knowledge of treatment.

The analysis population is defined by treatment exposure and availability of valid baseline and post-baseline efficacy assessments, but its size is not reported. The registry record does not explain missing-data handling, the statistical model, model covariates, sensitivity analyses, or a detailed analysis plan. It also does not report multiplicity procedures.

Safety results are grouped under labels that the record does not define. As a result, the group-specific counts cannot be confidently interpreted as treatment comparisons or linked to distinct exposure categories. Death entries are null rather than reported numerical counts. The record also does not report details such as dose, adherence, or the preceding adjunctive therapies, limiting clinical characterization of the intervention and participants’ treatment histories.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Brexpiprazole as Adjunctive Therapy With Major Depressive Disorder and an Inadequate Response to Previous Adjunctive Therapy — NCT02012218.
• Registry record last updated 2015-12-29; status last verified 2015-11.
• Results first posted 2015-10-08.
• 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

The registry record describes a completed Phase 3b, multicenter, open-label, exploratory, single-group trial of adjunctive brexpiprazole in adults with MDD and an inadequate response to previous adjunctive therapy. Enrollment was 61. The primary endpoint was least-squares mean change from baseline to Week 6 in MADRS total score, with standard error listed as the dispersion measure.

The primary efficacy population was defined by taking at least one dose and having valid baseline and post-baseline efficacy assessments. Its size and the numerical primary outcome are not reported in the registry record. The record also lists adverse-event counts across five groups, but does not explain the group labels. It does not provide a randomized comparator, so efficacy and safety entries should be read descriptively rather than as controlled treatment comparisons.