Long-term Study of Asenapine in Participants With Residual Subtype, Receiving Multiple or/and High Dose Drugs, or Treatment Refractory Schizophrenia (P06238): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Long-term Study of Asenapine in Participants With Residual Subtype, Receiving Multiple or/and High Dose Drugs, or Treatment Refractory Schizophrenia (P06238) (NCT01244828), a non-randomized phase 3 study. The primary outcome is Change From Baseline in Weight at Week 52.

2. Clinical Question

The study addressed a long-term treatment question in a group described as having particular clinical circumstances, including residual symptoms, treatment with multiple or high-dose drugs, treatment-refractory schizophrenia, or older age. The registry does not give separate primary-outcome results for those subgroups, so the weight outcome cannot be interpreted as a set of subgroup comparisons.

The question is descriptive rather than comparative. Without a separate control group, a change in weight over time cannot by itself distinguish changes associated with asenapine from changes that might have occurred for other reasons during follow-up. The registry record also does not report the numerical primary outcome needed to describe the direction, size, or precision of the observed mean change.

3. Trial Design

This was a Phase 3, multi-site, open-label, single-group study of asenapine in participants with schizophrenia. Allocation was non-randomized, and masking was absent. The registry lists enrollment of 157 participants and describes treatment for up to 52 weeks. The study is marked completed.

Participants received asenapine at 5 mg twice daily during the first week of treatment. After that, the described regimen allowed either 5 mg or 10 mg twice daily. The registry calls the dosing approach fixed-flexible; it does not report the rules used to select or change the dose, or how many participants received each dose.

The primary outcome was change from baseline in weight at Week 52, with the measurement period described as baseline and Week 52. The primary outcome population consisted of participants who received at least one dose and had a value at both time points. This definition means that the primary outcome does not necessarily include every enrolled participant. The number meeting this outcome-population definition is not reported in the registry record.

The stated study population included people with residual subtype schizophrenia, those receiving multiple or high-dose antipsychotic drugs, people with treatment-refractory schizophrenia, and elderly participants with schizophrenia. The record does not report how enrollment was distributed across these descriptions, or whether categories overlapped.

Study start is recorded as 2011-04-05, and primary completion as 2014-08-21. These dates describe the registry record; they do not provide individual participants’ follow-up durations. The planned treatment period was up to 52 weeks, but the record does not report how many participants completed that period or had a Week 52 weight measurement.

Because there was one treatment group and no randomization or masking, the study design supports description of outcomes during treatment, not a randomized estimate of treatment effect relative to a comparator. Further details of the protocol and statistical analysis plan 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.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Participants who received at least one dose of study drug and had both a baseline and a Week 52 value of the measure.

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 From Baseline in Weight at Week 52, measured over Baseline and Week 52.

The primary endpoint is change in weight from baseline to Week 52, measured in kilograms. For each participant, the registry defines this change as the Week 52 weight minus the baseline weight. Under that definition, a positive value would represent a higher Week 52 measurement than baseline, and a negative value would represent a lower one. The registry record does not provide the mean change or its standard deviation, so the direction and magnitude of the group’s result cannot be stated.

Weight is a continuous measure, meaning it can take a range of numerical values rather than belonging to a small set of categories. A mean change offers a group-level description of the average within-participant change among those included in the endpoint population. The standard deviation describes how dispersed individual changes are around that mean; it is not a measure of uncertainty in the estimated mean.

Using the same participants’ baseline and follow-up measurements focuses the endpoint on change over time rather than on a single weight measurement. It also requires measurements at both time points. Participants without a Week 52 value are not part of the registry’s stated primary outcome population, and the record does not explain how missing measurements were handled in any broader analysis.

As a general statistical point, this kind of endpoint can describe change during follow-up, but a single-group mean change does not establish what would have happened without the study treatment. The endpoint’s clinical interpretation also depends on the size and precision of the estimate and on relevant context; those numerical primary-result details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean change represent?

The endpoint is a continuous measure, and the registry specifies the mean as its summary. Each participant’s change is defined as Week 52 weight minus baseline weight. The group mean is the average of those individual changes among participants in the stated endpoint population. It is therefore a summary of within-participant differences, not the difference between two unrelated group averages.

As a general statistical explanation, the mean can provide a concise measure of the center of a distribution. It can also be influenced by unusually large or small individual changes. A mean alone does not describe the full distribution, which is why the registry’s stated use of a standard deviation is relevant. The standard deviation describes the spread of individual values around the mean. It does not, on its own, say how precisely the mean has been estimated.

What would a confidence interval tell a reader?

As a general concept, a confidence interval gives a range of values compatible with an estimate under the assumptions of the statistical method used. It helps communicate uncertainty in the estimate, while the standard deviation describes variability among individuals. A narrow interval generally indicates greater precision than a wide interval, but precision is not the same as freedom from bias or confounding.

A confidence interval for the primary mean change is not reported in the registry record. Nor are a p-value or a model-based estimate reported. Without a numerical estimate and an uncertainty measure, the magnitude and precision of the primary result cannot be evaluated from this record. The absence of those details does not imply that the change was zero or that an analysis found no evidence of change.

Why does the endpoint population matter?

The primary endpoint population includes participants who received at least one dose and had both baseline and Week 52 values. This is a measurement-based definition. It does not state that every enrolled participant contributed to the endpoint, and the number who met the definition is not reported in the registry record.

As a general statistical point, requiring a follow-up measurement can make the analyzed group differ from the group initially enrolled. If the availability of follow-up measurements is related to participants’ outcomes or circumstances, an estimate among those with complete measurements may not describe all enrolled participants. Whether that concern applies cannot be determined from the registry record: reasons for missing measurements, the amount of missingness, and any methods for addressing it are not reported.

What does the design permit?

The study is single-group, non-randomized, and open-label. As a general explanation, random allocation to separate groups can help make a comparison less vulnerable to systematic differences between groups. Here, there is no randomized comparator group. An endpoint measured from baseline to follow-up can describe what happened among participants with the required measurements, but it does not by itself estimate the difference between outcomes under asenapine and outcomes under an alternative condition.

Open-label means masking was absent, as recorded. In general, knowledge of treatment assignment can affect reporting, assessment, or other aspects of a study, depending on the outcome and procedures. Weight is a numerical measurement, but the registry does not describe measurement procedures or any safeguards against measurement differences. It would be inappropriate to infer a specific bias from the design alone.

What does the record say about the analysis?

The registry lists nine outcome measures and zero analyses. The record defines the primary measure as a mean with standard deviation, but it does not report the numerical summary for that endpoint, an inferential test, a confidence interval, or a statistical model. The statistical analysis plan, including any adjustments or sensitivity analyses, is not reported in the registry record.

As a general statistical point, a model may be used to account for features of the data or to adjust for prespecified factors, but the choice depends on the question and the data. No particular model should be attributed to this study from the information recorded. The same caution applies to assumptions about normality, outliers, repeated-measure methods, or the handling of incomplete observations: those procedures are not reported in the registry record.

The registry describes a fixed-flexible dose, but the method for choosing between the later doses is not stated. Therefore, the study record does not support a dose-response analysis or an interpretation of differences between dose groups. More generally, analyses of groups formed after treatment begins can be affected by differences in the participants assigned to those groups, so such comparisons would require careful methods and clear reporting.

The study’s descriptive endpoint and its design should be read together. The endpoint definition says what quantity was intended for summarization; it does not supply the result or establish a causal effect. The missing numerical result, uncertainty measures, analysis details, and endpoint-population count leave the principal statistical interpretation incomplete.

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("Asenapine")
n   <- c(79)
m   <- c(0.25)
sp  <- c(5.23)
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  Asenapine  79  0.250  5.230  -0.921  1.421

11. Multiplicity, Missing Data and Analysis Populations

The registry lists nine outcome measures, but it does not report the analysis details for them. It identifies change in weight at Week 52 as the primary outcome, yet the primary numerical result is not reported in the registry record. The record lists zero analyses. A statistical analysis plan, including a hierarchy of outcomes, is not reported.

As a general statistical explanation, multiplicity arises when several outcomes, time points, subgroups, or statistical tests are considered. Examining multiple results can increase the chance of finding an apparently notable result by chance. Researchers may address this with a prespecified hierarchy or adjustment procedure, but whether any such approach was used in this study is not reported in the registry record. No adjustment method or family of tests should be assumed.

The primary endpoint population required at least one dose and both baseline and Week 52 weight measurements. The number of participants satisfying that definition is not reported. Nor are the amount and reasons for missing weight data, the number completing follow-up, or the method used to handle missing values reported in the registry record.

As a general point, complete-measurement analyses can be difficult to interpret if people with missing follow-up differ in relevant ways from those with observed measurements. Methods such as imputation or models using incomplete repeated measurements may be considered in some studies, but use of any particular method is not reported. No assumption about why measurements are missing can be made from the record.

The registry’s endpoint definition describes an analysis population, but does not name a broader analysis set or explain whether other populations were considered. Thus, the population-level scope of any numerical result cannot be assessed beyond the stated eligibility definition, and the missingness and multiplicity procedures remain unclear.

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: schizophrenia (2.5%), pneumonia (1.3%), pneumonia aspiration (1.3%), abdominal abscess (0.6%), bladder neoplasm (0.6%).

For the asenapine group, the registry reports 157 participants at risk for serious adverse events and 14 participants affected. It reports 157 at risk for other adverse events and 111 affected. These figures are counts as recorded; they should not be interpreted as a comparison with another treatment because the study had no comparator group.

The registry lists the following serious adverse event terms and percentages: Schizophrenia, 2.5%; Pneumonia, 1.3%; Pneumonia aspiration, 1.3%; Abdominal abscess, 0.6%; Bladder neoplasm, 0.6%; and Completed suicide, 0.6%. These are the listed terms and values. The record does not provide additional context about each event, its timing, or its relationship to study treatment.

Adverse-event counts describe reported events in the study group; they do not by themselves establish that treatment caused an event. The registry does not report a death count for this group. It also does not state in the information recorded whether listed serious-event terms are mutually exclusive, so they should not be added together to infer a total number of affected participants.

As a general statistical point, safety counts depend on how events are collected, classified, and followed. Details of those procedures are not reported in the registry record. The figures should therefore be read as the recorded safety summaries, not as a comparative estimate of risk.

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

The record describes a completed, long-term study of asenapine in a single group of participants with schizophrenia. It identifies change in weight from baseline to Week 52 as the primary outcome and specifies that eligible endpoint participants needed both measurements and at least one dose. Those details establish the intended measurement and the stated population for its summary.

The record does not report the mean weight change or its standard deviation. It therefore does not support a statement about the direction or size of average change, the spread of individual changes, or the precision of the estimate. No confidence interval, p-value, or primary-outcome analysis is reported in the registry record. Missing numerical results cannot be interpreted as evidence that no change occurred.

The design also limits what a change over time could mean. With no randomized comparator group, the study cannot directly contrast participants’ outcomes during asenapine treatment with outcomes under another treatment or control condition. A before-and-after observation is not, by itself, a causal estimate. The record also does not report dose-specific results or separate primary outcomes for the different participant characteristics described in the study.

The safety record reports 14 participants affected by serious adverse events and 111 affected by other adverse events, with 157 at risk in each category. It also lists specific serious adverse event terms and percentages. These are descriptive safety figures for the study group and do not establish causation or provide a treatment comparison.

As a general statistical point, interpretation depends on both the estimate and its uncertainty, as well as the design and completeness of the data. The registry record leaves the main numerical primary result, endpoint sample count, missing-data handling, and analysis methods unreported. Accordingly, the posted information supports a description of the study’s design and recorded safety counts, but not a quantified conclusion about the primary weight outcome.

14. Why This Trial Matters Statistically

This study is statistically notable for asking a long-term question in a population described by several clinical circumstances while using a single-group design. The registry identifies an objective continuous primary outcome—weight change from baseline to Week 52—and gives an explicit definition of the individual change. Clear endpoint definitions matter because they specify what is being averaged and the direction represented by positive or negative change.

The record also illustrates why an endpoint definition is not a substitute for a result. The mean and standard deviation are named, and the population eligible for the endpoint is described, but the numerical summary and the number of participants contributing to it are not reported. Readers can understand the intended estimand more clearly than they can assess its value or precision.

The absence of a comparator is another central statistical feature. A single-group study can characterize outcomes during follow-up, but it cannot provide a randomized estimate of how those outcomes differ from a control condition. That distinction is important when interpreting changes over time, even when follow-up is long and the endpoint is measured numerically.

The registry’s safety counts offer descriptive information, while the lack of comparative allocation constrains their interpretation. The record reports participants affected by serious and other adverse events, but those counts do not establish causality or comparative risk. The list of serious event terms gives additional detail about what was recorded, without resolving those design limits.

Finally, the entry makes visible the role of reporting completeness in statistical interpretation. Analysis methods, missing-data procedures, and numerical primary results are not reported in the registry record. Without those items, readers cannot evaluate precision, robustness, or how the analyzed participants relate to everyone enrolled. The study’s statistical importance lies in recognizing both what its design and endpoint specify and what the recorded results do not allow readers to conclude.

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 for interpreting the primary outcome is that its numerical mean change and standard deviation are not reported in the registry record. There is consequently no basis in the recorded information for describing the size, direction, variability, or precision of the Week 52 weight change.

The primary endpoint population requires baseline and Week 52 measurements, but the number of participants meeting this definition is not reported. Although enrollment was 157, the record does not show how many contributed to the primary endpoint, completed the treatment period, or lacked follow-up measurements. Reasons for missing values and methods used to address them are also not reported.

The single-group, non-randomized, open-label design has no comparator. It cannot separate change during follow-up from change attributable to treatment, and it does not support a randomized treatment contrast. The record also does not report dose-specific outcomes, despite describing two possible doses after the first week, or separate endpoint results for the different clinical groups included in the study description.

Further statistical details are not reported in the registry record, including a confidence interval, p-value, model, analysis plan, multiplicity approach, and missing-data method. The record lists nine outcome measures and zero analyses, leaving the handling and interpretation of outcomes beyond the named primary endpoint unclear.

Safety interpretation is also limited to descriptive counts and listed serious event terms. A death count is not reported, and the registry information does not establish whether adverse-event categories overlap or whether events were judged related to treatment. These limits do not invalidate the recorded counts, but they restrict what can be inferred from them.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Long-term Study of Asenapine in Participants With Residual Subtype, Receiving Multiple or/and High Dose Drugs, or Treatment Refractory Schizophrenia (P06238) — NCT01244828.
• Registry record last updated 2024-05-28; status last verified 2022-02.
• Results first posted 2015-08-26.
• 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 3, multi-site, open-label, non-randomized, single-group study of asenapine in participants with schizophrenia. Enrollment was 157. Treatment began at 5 mg twice daily for the first week, followed by either 5 mg or 10 mg twice daily, for a treatment period of up to 52 weeks.

The primary outcome was change in weight from baseline to Week 52, calculated as Week 52 weight minus baseline weight. The endpoint population required at least one dose and measurements at both time points. The mean change, standard deviation, and number of participants in that population are not reported in the registry record.

The safety record reports 14 participants affected by serious adverse events and 111 affected by other adverse events, with 157 at risk in each category. The record lists nine outcome measures and zero analyses. Further analysis and missing-data details are not reported.