Open-Label Study of Intramuscular Olanzapine Depot in Patients With Schizophrenia or Schizoaffective Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Open-Label Study of Intramuscular Olanzapine Depot in Patients With Schizophrenia or Schizoaffective Disorder (NCT00088465), a non-randomized phase 3 study. The primary outcome is Number of Participants With Adverse Events (AE).

2. Clinical Question

The study concerns long-term treatment with intramuscular olanzapine depot in people with schizophrenia or schizoaffective disorder. Its stated objectives include evaluating long-term effectiveness, safety and tolerability, and blood levels during treatment. The primary outcome listed in the registry record is the number of participants with adverse events during the period from randomization to the end of the study, up to 76 months.

This is therefore a descriptive safety question within a treated group, not a randomized comparison of treatments. The registry record also lists symptom, quality-of-life, health-status, and psychiatric-visit outcomes, with endpoints at different time points. Their results are not reported in the registry record. No between-group question can be answered from this study design as described, because no control group is listed.

3. Trial Design

The registry record describes a Phase 3, open-label study with a single-group model, non-randomized allocation, and no masking. Enrollment was 931. The intervention was intramuscular olanzapine depot with flexible dosing and flexible intervals. The study is described as long-term and intended to enable longer-term treatment for patients completing other clinical studies.

The study started in August 2004, had primary completion in December 2010, and is listed as completed. The primary outcome timeframe is from randomization to the end of the study, up to 76 months. That wording should be read alongside the record’s explicit non-randomized allocation; it does not establish that participants were randomized within this study. The primary-outcome population description says “all randomized participants who took at least one dose,” which is not fully aligned with the listed non-randomized design. The record does not explain this terminology.

Open-label means that masking was not used, according to the registry entry. With no comparator group, the outcome figures describe events recorded among participants receiving the study drug; they do not estimate a contrast against another treatment or against no treatment. The record lists 20 outcome measures and no analyses. The specific statistical plan, including any planned comparisons or modeling approach, is 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: All randomized participants who took at least one dose of study drug.

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 Number of Participants With Adverse Events (AE), measured over Randomization to end of study up to 76 months.

The primary endpoint is the number of participants with adverse events. It is a count outcome: it records how many people in the stated study population were identified as having an event during the specified observation period. The timeframe is described as from randomization to the end of the study, up to 76 months. The population is described as participants who took at least one dose of study drug.

Counting participants with events is useful for summarizing the safety experience in a treatment group. It differs from counting every event occurrence: a participant may have more than one event, and the record does not clarify whether any reported counts represent people, event episodes, or both beyond the primary endpoint’s stated participant-count definition. Nor does it report the timing, duration, severity distribution, or relationship to treatment for each event in the primary outcome description.

For this single-group study, the count can describe what was recorded among treated participants. On its own, it cannot show how the event experience compares with another treatment, or what would have occurred without the study drug. The registry record reports 170 participants at risk and affected by serious adverse events, and 501 at risk and affected by other non-serious adverse events, in the listed group. Those are separate categories in the record; it does not state whether participants appear in both. The endpoint’s clinical interpretation therefore depends on the event definitions, ascertainment, and follow-up, details that are not fully reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

For a binary event outcome, each participant is classified according to whether the event was recorded during the defined observation period. A count of participants with the event is a straightforward descriptive summary. The interpretation depends on a clearly defined event, a specified population, and a consistent observation window. In this study, the primary endpoint is described as the number of participants with adverse events, and the timeframe extends from randomization to the end of the study, up to 76 months.

What does a count tell us?

A count answers how many participants were recorded as affected in the study group. It does not by itself convey how frequent events were relative to the amount of time participants were observed, how many events each person experienced, or how event risk changed over follow-up. For those questions, the analysis would need appropriately defined denominators and, where relevant, event dates or person-time. Such analyses are not reported in the registry record.

The record lists 170 participants affected by serious adverse events and 501 affected by other non-serious adverse events, each among 931 at risk in the group. These summaries should be kept separate. Without information about overlap, the categories cannot be combined to obtain the number affected by any event. Also, the term “at risk” is reported as a denominator; it does not explain whether every participant had the same duration of observation or whether all participants had complete follow-up.

What would uncertainty estimates add?

In general, a confidence interval gives a range of values compatible with the observed data under a specified statistical model and procedure. It communicates uncertainty about an estimated quantity; it is not a guarantee that the true value lies in that particular interval. For a single-group event summary, an interval could describe uncertainty in an event proportion if the necessary definition and assumptions were specified. The registry record does not report a confidence interval or an inferential method for this primary outcome, so no interval-based precision claim is available.

A p-value, in general, measures how unusual data at least as incompatible with a stated null model would be if that model and the test assumptions were true. It does not measure the size or clinical importance of an effect. No p-value or null comparison for the primary outcome is reported in the registry record. Since no control group is listed, a test of a treatment contrast is not available from the described design.

Why does the study structure matter?

In a randomized comparative study, random allocation can support a balanced comparison of groups, subject to adherence, missingness, and other design considerations. Here the record specifies non-randomized allocation and a single-group model. The adverse-event counts can describe the observed experience in that group, but they cannot separate effects of treatment from changes over time, participant characteristics, background risks, or other influences. This is a limitation of what the design can identify, rather than a defect that can be corrected by a more elaborate calculation on the same counts.

Open-label conduct also means masking was not used. In general, knowledge of treatment can influence reporting, clinical attention, or event classification, depending on how outcomes are collected. The registry record does not provide enough detail to assess the extent of any such influence. It does not report event-adjudication procedures or a detailed plan for collecting adverse events.

How should flexible dosing and follow-up be understood?

The intervention description specifies flexible dosing and flexible intervals. In general, treatment changes and varying time on treatment can make a single group’s cumulative event count difficult to compare with another setting. A count over extended follow-up reflects both whether events occurred and the opportunities to observe them. Analyses that account for time-to-event or differing observation time require participant-level timing data and a stated method; those results are not reported in the registry record. The timeframe of up to 76 months does not establish that every participant was followed for that duration.

The registry record lists no analyses. It does not report a statistical analysis plan, confidence intervals, adjusted models, or interim analyses. Thus, the summaries are best interpreted descriptively. General statistical methods can clarify what additional analyses might address, but cannot supply missing design details or recreate results that are not reported.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 20 outcome measures, including symptom-scale changes, quality-of-life and health-status measures, psychiatric visits, and the primary adverse-event count. When many outcomes or time points are assessed, the chance of at least one apparently unusual result can increase if each is tested separately. In general, multiplicity procedures can control that risk, or investigators can identify a limited set of primary hypotheses in advance. The analysis plan and any multiplicity adjustment are not reported in the registry record. No analysis results are listed, so it is not possible to determine which outcomes were analyzed or how they were interpreted.

Missing-data methods are also not reported. In long-term studies, participants may have different follow-up durations or may stop attending assessments. In general, missing outcome information can affect estimates when the likelihood of missingness is related to participant characteristics or outcomes. Assessing this requires details such as follow-up completeness, reasons for missing data, and the assumptions used in any analysis. Those details are not reported in the registry record.

The primary population description refers to all randomized participants who took at least one dose, while the design lists non-randomized allocation. This mismatch in wording is not resolved by the record. It also does not give a fuller analysis-population definition or explain how participants with incomplete follow-up were handled. The number enrolled is reported, but enrollment alone does not establish how many contributed information to each outcome or endpoint. These omissions limit assessment of analysis populations, missingness, and the robustness of any unreported estimates.

11. 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 (3.8%), psychotic disorder (2.1%), sedation (1.3%), suicidal ideation (0.9%), agitation (0.6%).

The serious adverse-event summary lists 931 participants at risk and 170 affected in the intramuscular olanzapine depot group. The other non-serious adverse-event summary lists 931 at risk and 501 affected. These are participant counts as recorded, rather than event totals or comparative treatment effects. The record does not indicate whether the two categories overlap, so they should not be added to estimate the number of participants with any adverse event.

The listed serious adverse-event terms include schizophrenia (3.8%), psychotic disorder (2.1%), sedation (1.3%), suicidal ideation (0.9%), agitation (0.6%), and somnolence (0.5%). The registry record does not report the denominator or counting rules for these term-specific percentages. It also does not provide a comparison group, event-level timing, or a causal assessment for these entries. The record’s death count is not reported.

These summaries describe what was recorded in this study group. They do not establish whether treatment caused an event, nor do they show how the counts would compare under another treatment. The duration of observation varied or was complete for all participants is not reported in the registry record.

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

The central result available for interpretation is descriptive: the registry record reports counts of participants affected by serious and other non-serious adverse events in a single group receiving intramuscular olanzapine depot. It also identifies several serious adverse-event terms and their listed percentages. These figures characterize the record’s reported safety observations; they are not a controlled estimate of treatment effect.

The study is open-label, non-randomized, and single-group, with no comparator listed. Consequently, the event counts cannot determine whether the observed events occurred more or less often than they would have without treatment or with a different treatment. They also cannot establish that treatment caused a specific event. Those questions require an appropriate comparison and analysis, neither of which is reported in the registry record.

The record’s long-term objective and the timeframe of up to 76 months indicate an intended focus on extended treatment, but do not show that every participant contributed the same follow-up. The registry entry does not give follow-up completeness or person-time. The counts alone therefore do not describe how event experience varied over time.

Nor do the listed secondary outcomes establish clinical changes: results for PANSS measures, CGI-S, quality of life, SF-36, and psychiatric visits are not reported in the registry record. No confidence intervals or statistical tests for the primary outcome are reported. The available evidence should therefore be read narrowly: it documents the adverse-event counts and listed terms for the study group, while leaving comparative efficacy, precision, event timing, and causal interpretation unresolved.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of the distinction between describing an observed group and estimating a comparative effect. A long-term, single-group record can document how many participants were recorded as affected by specified adverse-event categories during study follow-up. Such data can contribute a descriptive account of the study experience, but without a comparator they do not quantify a treatment contrast.

The record also illustrates why denominators and outcome definitions matter. It reports separate counts for serious and other non-serious adverse events, but does not state whether participants overlap across categories. The number of participants with any adverse event therefore cannot be inferred by combining those counts. Term-specific percentages are listed, while their denominators and counting rules are not reported. Keeping the categories and summaries distinct avoids claims that exceed what the record establishes.

Long follow-up raises further statistical questions. A cumulative participant count does not reveal how long participants were observed, when events occurred, or whether observation was comparable across participants. Those details affect whether a count, a rate, or a time-to-event analysis is most useful. The registry record does not report the timing information or analyses needed to answer these questions.

Finally, the registry lists multiple clinical and safety outcomes but no analyses. This makes multiplicity, missing-data handling, and analysis-population choices impossible to evaluate. The case underscores the value of transparent reporting of analysis methods, denominators, follow-up, and uncertainty alongside outcome counts. Here, the most defensible interpretation remains descriptive and limited to the reported single-group safety summaries.

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.

The most important limitation for interpretation is the absence of a comparator. Because the registry record describes non-randomized allocation and a single-group model, the event counts cannot estimate a relative risk or treatment difference. The open-label design and lack of masking may also affect reporting or classification in general, but the record does not describe procedures that would allow the magnitude of any such influence to be assessed.

The primary population wording refers to randomized participants despite the non-randomized design. The registry record does not explain this discrepancy or provide a more detailed analysis-population definition. The entry reports 931 at risk in each adverse-event category, but does not describe individual follow-up duration or completeness. The timeframe extends up to 76 months, which does not establish uniform follow-up.

The adverse-event information is limited to counts and selected terms. Whether serious and other non-serious categories overlap, how events were adjudicated, and how the term-specific percentages were calculated are not reported in the registry record. The death count is not reported. No confidence intervals, hypothesis tests, adjusted analyses, or detailed statistical plan are listed.

The record lists multiple secondary outcomes, but their results and missing-data handling are not reported. The lack of analysis information prevents evaluation of multiplicity, precision, or the robustness of outcome estimates. These limitations mean the available summaries are suitable for describing the reported event counts, but not for making comparative or causal conclusions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Open-Label Study of Intramuscular Olanzapine Depot in Patients With Schizophrenia or Schizoaffective Disorder — NCT00088465.
• Registry record last updated 2012-01-11; status last verified 2011-12.
• Results first posted 2012-01-11.
• 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

The registry record describes a completed Phase 3, open-label, non-randomized, single-group study of intramuscular olanzapine depot in people with schizophrenia or schizoaffective disorder. Enrollment was 931. The intervention used flexible dosing and flexible intervals. The study started in August 2004, with primary completion in December 2010.

The primary outcome is the number of participants with adverse events during a timeframe described as from randomization to the end of the study, up to 76 months. The record lists 170 participants affected by serious adverse events and 501 affected by other non-serious adverse events, each with 931 at risk. It also lists serious adverse-event terms with percentages. The registry record does not report a comparator, primary-outcome confidence intervals or tests, analysis results for the listed secondary outcomes, or a detailed statistical plan. The stated analysis population’s reference to randomized participants is not reconciled with the non-randomized design.