A Long-term Trial of OPC-34712 in Patients With Schizophrenia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Long-term Trial of OPC-34712 in Patients With Schizophrenia (NCT01456897), a na phase 3 study. The primary outcome is Percentage of Participants With Adverse Events.

2. Clinical Question

The registry record describes a trial of long-term OPC-34712 administration in patients with schizophrenia. Its stated purpose was to investigate safety and efficacy. The primary outcome is the percentage of participants with adverse events from baseline up to 52 Weeks, with treatment-emergent adverse events defined as events that started after investigational medicinal product treatment began.

The record also lists changes in Positive and Negative Syndrome Scale (PANSS) total, positive-subscale and negative-subscale scores, change in Clinical Global Impression-Severity of Illness (CGI-S), and Clinical Global Impression-Global Improvement (CGI-I). These measures address symptom severity and clinical global impressions, but their results are not reported in the registry record.

These details frame the question as an assessment of outcomes observed during treatment, rather than a randomized comparison of OPC-34712 against a control. The registry record does not report a comparative efficacy estimate or the results for the listed symptom measures.

3. Trial Design

This is a Phase 3, completed, single-group trial sponsored by Otsuka Pharmaceutical Co., Ltd. The registry record lists 282 participants enrolled, a start date of 2011-10, and primary completion in 2015-05. It lists no allocation method and no masking. Those design features mean the record does not describe a randomized, blinded comparison against a control group.

OPC-34712 is the listed drug intervention. The record distinguishes New Subjects from Rollover Subjects in its adverse-event information. These categories do not establish a randomized comparison, and their figures should not be read as treatment-versus-control results. The record does not describe the source of the rollover participants, their prior treatment, or the criteria used to place participants in either category.

The primary outcome is the percentage of participants with adverse events, assessed from baseline up to 52 Weeks. Its definition of a treatment-emergent adverse event is an adverse event that started after investigational medicinal product treatment began. The safety population is described as participants who had treated investigational medicinal product.

The record lists secondary outcomes for PANSS total, positive-subscale and negative-subscale change from baseline, CGI-S change from baseline, and CGI-I. It reports six outcome measures overall, but no analysis records and no numerical results for these efficacy measures are included in the information available for this analysis. The registry record also does not report the planned analysis methods, the protocol’s sample-size justification, or an interim-analysis plan. Accordingly, the design can be described from the recorded features, but not extended into assumptions about how the investigators planned or carried out analyses beyond those details.

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: Safety sample included those participants who had treated IMP.

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 Percentage of Participants With Adverse Events, measured over From Baseline up to 52 Weeks.

The primary endpoint is the percentage of participants with adverse events from baseline up to 52 Weeks. The registry defines a treatment-emergent adverse event as an event that started after the start of investigational medicinal product treatment. The specified safety population includes participants who had treated investigational medicinal product.

In general, an event-count endpoint records how many participants experienced an event in the defined observation period; a percentage expresses that count relative to a specified population. Such outcomes are used to describe the frequency of reported safety events during treatment. They do not, by themselves, establish that treatment caused an event. A treatment-emergent definition establishes timing relative to treatment start, not causation.

The record’s primary endpoint title refers to adverse events overall, while the adverse-event information also separates serious events from other events. The recorded serious-event counts for New Subjects and Rollover Subjects are available, but the primary endpoint result is not reported in the registry record as a percentage. The information available also does not identify an overall percentage of participants with any adverse event for the stated timeframe.

Interpretation therefore depends on keeping the endpoint definition, observation period, and safety population in view. The event counts reported for separate categories should not be substituted for an overall primary-endpoint percentage or treated as a comparison between randomized groups. The record does not provide enough detail to assess differences in event ascertainment or duration of individual participants’ follow-up.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Several statistical distinctions are important for reading this record. The trial is identified as single-group, with allocation listed as NA and masking as NONE. Those entries describe the recorded design; they do not support treating the New Subjects and Rollover Subjects categories as randomized arms. Their adverse-event summaries are descriptive categories, not a controlled treatment contrast.

What does a participant count represent?

The primary outcome is defined as the percentage of participants with adverse events. For an endpoint of this kind, the numerator is the number of participants meeting the event definition, and the denominator is the relevant population under observation. The percentage is meaningful only alongside a clear outcome definition, observation period, and denominator. The record defines treatment-emergent events by their start after treatment begins and states that the safety population includes participants who had treated investigational medicinal product.

The adverse-event record gives counts at risk and counts affected in each subject category. These counts describe participants, not necessarily the total number of event episodes. A participant may experience more than one event, so participant counts and episode counts answer different questions. The registry record does not report episode totals or participant-level detail in the information available for this analysis.

Why is the endpoint timeframe important?

The primary outcome timeframe is from baseline up to 52 Weeks. In general, event counts can depend on how long participants are observed and whether observation is complete. A fixed stated timeframe helps define the period of interest, but the registry record does not report individual follow-up duration, censoring details, or whether every participant contributed observation across the entire period. The counts should therefore be read as the recorded summaries, not converted into a rate over person-time.

How should the group labels be interpreted?

New Subjects and Rollover Subjects are labels used in the adverse-event data. The record does not say that participants were assigned randomly to those categories, nor does it identify one category as a control. General comparisons between groups require attention to how participants entered each group and whether their characteristics and observation periods are comparable. Those details are not reported in the registry record. For that reason, a difference in counts between these categories should not be interpreted as an estimate of the effect of OPC-34712.

What does statistical uncertainty add?

In general, an estimate from a sample has uncertainty. A confidence interval communicates that uncertainty under a specified statistical method; a narrower interval indicates greater precision than a wider interval, all else equal. A p-value addresses compatibility between data and a specified null model, rather than the size or clinical importance of an effect. The registry record does not report a confidence interval or p-value for the primary endpoint in the information available for this analysis. No inferential comparison should be inferred from the participant counts alone.

For event data, statistical methods may also need to account for how events cluster within participants and whether observation time differs. General methods for repeated events or time-to-event outcomes can address questions that a simple participant count does not. The registry record does not report that such methods were used, and the available endpoint is a participant-count measure. It would be inappropriate to attribute an unreported model or adjustment to the investigators.

What can be said about analysis planning?

The record reports six outcome measures and no analysis records. It lists secondary outcome names but does not report their estimates, uncertainty, or analysis methods. The statistical analysis plan, sample-size justification, handling of missing data, covariate adjustment, interim analyses, and multiplicity procedure are not reported in the registry record. Those omissions limit assessment of how the trial’s analyses were planned and how results were selected or interpreted.

A planning illustration based on an observed effect is not equivalent to the trial’s original design justification or an observed power calculation. In general, sample-size planning depends on the target effect, variability or event frequency, chosen error rates, allocation, and analysis method. The registry record does not provide the study’s own sample-size justification. Any planning illustration should therefore be kept separate from what the trial observed and should not be treated as evidence that the trial had adequate power for an outcome.

Finally, adverse-event summaries and symptom outcomes serve different statistical purposes. The former describe safety events over a stated period, while PANSS and global-impression measures concern changes in clinical status. The record lists the latter but reports no results for them. Neither endpoint type can fill in for the other, and absent efficacy results do not establish either benefit or lack of benefit.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists six outcome measures, including the primary adverse-event outcome and secondary symptom and global-impression measures. It does not report a multiplicity procedure, such as an adjustment for testing multiple outcomes, or explain how the listed outcomes were prioritized in the analysis. When several outcomes are assessed, general statistical practice recognizes that the chance of at least one apparently unusual result can increase if each is tested separately without an appropriate plan. The record does not provide enough detail to determine how this issue was handled.

Missing-data methods are not reported in the registry record. The available information does not describe the number of participants with missing outcome measurements, reasons for missingness, imputation methods, or sensitivity analyses. It is therefore not possible to assess whether missing observations affected the reported safety or efficacy summaries.

The safety population is described as participants who had treated investigational medicinal product. The record does not report a fuller definition of analysis populations for the secondary outcomes, nor does it describe how participants were included in each analysis. It also reports no analysis records. Consequently, the stated outcome list should not be mistaken for a complete statistical analysis plan, and the absence of reported analyses does not establish that no analyses were conducted. The registry record does not report the statistical plan, interim analyses, or sample-size justification.

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 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 (13.3%), gastrointestinal haemorrhage (1.0%), meningitis aseptic (1.0%), heat illness (1.0%), toxicity to various agents (1.0%).

The serious adverse-event summaries are grouped by subject category. For New Subjects, 183 participants are listed at risk and 19 are listed as affected; for Rollover Subjects, 98 are listed at risk and 18 as affected. The record lists 0 deaths for each category. These are participant counts and should not be read as the total number of serious-event episodes.

The serious-event terms listed include Schizophrenia at 13.3%, and Gastrointestinal haemorrhage, Meningitis aseptic, Heat illness, Toxicity to various agents, and Dehydration at 1.0% each. The registry record does not provide the denominators and calculation details for each term-level percentage in the information available for this analysis. The percentages are therefore best read as the record’s reported values, without reconstructing their basis.

These summaries do not establish that OPC-34712 caused the events. The trial has a single-group design and no randomized control comparison is reported. The adverse-event endpoint is treatment-emergent, meaning an event started after treatment began; that timing definition alone does not establish causation. The primary endpoint’s overall percentage with adverse events is not reported in the registry record.

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

The record documents a Phase 3, completed, single-group study of long-term OPC-34712 in patients with schizophrenia. It identifies a safety outcome, a timeframe extending from baseline up to 52 Weeks, a safety-population definition, and adverse-event counts for New Subjects and Rollover Subjects. It also lists serious-event terms and records no deaths in either subject category.

Those details describe what the registry record reports; they do not establish a treatment effect. There is no randomized control group identified, and the two subject categories are not described as comparable treatment arms. The observed counts cannot isolate the contribution of treatment from other possible explanations, and they should not be used as a direct estimate of a treatment-versus-control difference.

The record’s stated purpose includes efficacy, and it lists PANSS and clinical global-impression outcomes. However, their results are not reported in the registry record. The primary endpoint is named as the percentage of participants with adverse events, but its overall percentage is also not reported in the available information. Thus, the posted results do not permit a complete assessment of the primary endpoint or the listed efficacy outcomes.

In general, statistical interpretation depends not only on the observed estimate but also on its uncertainty, the analysis population, and the study design. The record does not report a confidence interval or p-value for the primary endpoint, or the analysis methods for the listed outcomes. These omissions prevent assessment of statistical precision and the investigators’ inferential approach.

The results should therefore be read as a limited registry description of selected safety observations, not as proof that treatment did or did not change risk or symptoms. The absence of reported efficacy estimates is not evidence of no efficacy, just as reported adverse events are not by themselves evidence that treatment caused them. No medical conclusion about an individual’s care follows from these registry summaries.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of why study design and outcome reporting determine what can be concluded. The record identifies a single-group design, no allocation method, and no masking. These features make the adverse-event results descriptive rather than a randomized comparison. Subject categories within the safety summaries do not create a control group or a causal contrast.

The endpoint definition also matters. A treatment-emergent event is defined by when it began relative to treatment, and the primary outcome is framed as the percentage of participants with adverse events during a stated timeframe. This supports a question about events observed after treatment initiation, but timing is not the same as causation. A clear denominator and endpoint result are needed to interpret a percentage; the overall primary-endpoint percentage is not reported in the registry record.

The record further illustrates the difference between outcome registration and outcome reporting. It lists symptom and global-impression measures, but does not report their results or analyses in the information available for this analysis. Listing outcomes alone does not permit assessment of effect size or precision. The record also does not report the multiplicity procedure, missing-data approach, analysis plan, or sample-size justification.

For biostatisticians and clinical researchers, the central lesson is to match claims to the design and the reported evidence. Participant counts can describe recorded events, but they do not replace a comparator, uncertainty estimates, or the prespecified analysis details needed for stronger inferences. This record makes the limits of registry-based interpretation visible: substantial descriptive information can coexist with important gaps in inferential reporting.

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 record constrain interpretation. The study is listed as single-group, with allocation NA and masking NONE. No randomized comparator is identified, so the safety counts do not support a like-for-like treatment comparison. The New Subjects and Rollover Subjects categories are not described in enough detail to assess how participants entered each category or whether follow-up and participant characteristics were comparable.

The primary outcome is identified as the percentage of participants with adverse events from baseline up to 52 Weeks, but that overall percentage is not reported in the registry record. The available adverse-event counts distinguish serious events from other events, but the record does not provide the overall primary endpoint result or its uncertainty. Individual follow-up duration and details of event ascertainment are also not reported in the information available for this analysis.

The record lists six outcome measures, but no analysis records. Numerical findings for the PANSS and clinical global-impression outcomes are not reported. Nor are the statistical analysis plan, missing-data approach, multiplicity procedure, interim analyses, or sample-size justification reported in the registry record. These gaps prevent assessment of the planned inferential framework and the precision of the reported outcomes.

The adverse-event information includes term-level percentages, but the denominator and calculation details for each term are not stated in the available record. Finally, treatment-emergent timing does not prove causation, and the single-group design limits attribution of events or changes to the intervention. These limitations do not negate the recorded observations; they define the boundaries of what those observations can establish.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Long-term Trial of OPC-34712 in Patients With Schizophrenia — NCT01456897.
• Registry record last updated 2019-12-30; status last verified 2016-10.
• Results first posted 2019-12-30.
• 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

The registry record describes NCT01456897, a Phase 3, completed, single-group trial sponsored by Otsuka Pharmaceutical Co., Ltd. It lists 282 participants enrolled, a start date of 2011-10, and primary completion in 2015-05. The population is patients with schizophrenia, and the listed intervention is OPC-34712. Allocation is recorded as NA and masking as NONE.

The primary outcome is the percentage of participants with adverse events from baseline up to 52 Weeks. The safety population includes participants who had treated investigational medicinal product. The record reports serious and other adverse-event counts for New Subjects and Rollover Subjects, and lists serious-event terms. No deaths are recorded in either category.

Secondary outcomes include PANSS total, positive-subscale and negative-subscale changes, CGI-S change, and CGI-I. The record lists six outcome measures and no analysis records. The primary endpoint percentage, efficacy results, statistical analysis plan, and sample-size justification are not reported in the registry record.