Seroquel XR in Adults With Schizophrenia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Seroquel XR in Adults With Schizophrenia (NCT00852631), a na phase 3 study. The primary outcome is Change in Positive and Negative Syndrome Scale (PANSS) Total Score.

2. Clinical Question

In practical terms, the study asked whether PANSS total scores changed during treatment in this enrolled group, while also recording safety and acceptability. Because the design has no control group, any observed within-group change would not by itself distinguish a treatment-associated change from other explanations. The registry record does not report why the study was terminated or provide a numerical primary endpoint result.

3. Trial Design

This was a Phase 3, open-label, multicentre, single-group study of oral quetiapine in adults with schizophrenia. The record lists 28 participants enrolled and identifies AstraZeneca as the sponsor. Allocation is recorded as NA, masking as none, and the model as single-group. These design details describe a study without randomized assignment to different treatment arms and without masking.

The brief summary says the study was intended to evaluate efficacy in patients with acute worsening symptoms and to assess safety and acceptability with daily oral dosing up to 600 mg once a day for 42 days. The primary outcome was change in PANSS Total Score from Day 1 to Day 42, the final visit, or withdrawal. The record gives a primary completion date of 2010-05 and a study start of 2009-02. Its current status is listed as terminated; the reason for termination is not reported in the registry record.

The registry notes 28 participants at baseline and 17 at Day 42 for the primary endpoint, explaining that some participants withdrew or terminated during the study. That distinction matters: the enrollment figure is not the same as the number contributing a Day 42 score. The record does not state how many participants contributed paired measurements, how withdrawal visits were handled in the analysis, or whether the endpoint analysis included all enrolled participants.

Three outcome measures are listed, including the primary PANSS outcome and Clinical Global Impression - Severity of Illness (CGI-S) entries. The CGI-S wording appears twice in the listed secondary outcomes. The registry record does not report a statistical analysis for these outcomes. The design and posted information should therefore be read as a description of the study and its recorded measures, not as evidence of a comparative treatment effect.

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: On Day 1, baseline assessments will be performed, and patients will be assigned to Seroquel XR at 300 mg. On Day 2 all patients are assigned to reach target dose of Seroquel XR at 600 mg. Administration of study medication continue with Seroquel XR 600 mg daily until Day 42. Each visit will have ± 3 days window period.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The number of patient at Day 42 (n= 17) is different than at Baseline (n= 28), because some of them withdraw/terminate during the study.

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 Positive and Negative Syndrome Scale (PANSS) Total Score, measured over From Day 1 (baseline) to Day 42.

The primary endpoint is change in PANSS Total Score from Day 1 (baseline) to Day 42, the final visit, or withdrawal. PANSS is used to quantify symptom severity across positive and negative symptom domains and other aspects captured by its total score. Here, the registry identifies the unit as scores on a scale and specifies that the endpoint is a mean change. It states that total PANSS ranges from 30 to 210 and that a decrease from baseline of at least 30% is considered better. That description is part of the registry entry; it does not report how many participants met that criterion.

Change scores summarize how each participant's score differs between a baseline assessment and a later assessment. In general, they can describe within-person movement over time, while the group mean summarizes the average movement among participants included in the analysis. The standard deviation describes how dispersed individual change scores are around that mean. Neither statistic alone explains why scores changed.

The endpoint is clinically interpretable as a measure of symptom-severity change, but its analysis depends on which assessments and participants are included. The registry gives baseline and Day 42 counts, and says the endpoint could use Day 42, the final visit, or withdrawal. It does not report the observed mean change, standard deviation, confidence interval, or analysis population. As a result, the posted record identifies what was intended to be measured but does not allow the size or precision of the observed change to be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies the primary outcome as a mean change in PANSS Total Score and names standard deviation as the dispersion measure. It does not report the outcome estimate or an analysis. The explanations below describe how these statistical concepts are generally used; they should not be taken as confirmation that a particular method was used in this study.

What does a mean change summarize?

For a continuous outcome, change is generally formed by comparing a participant's score at follow-up with that participant's baseline score. A mean change summarizes those individual changes across the participants included in the analysis. The direction of change depends on the scale: the registry says a decrease from baseline is considered better for PANSS. A group mean can be useful, but it does not show whether most participants had similar changes or whether the average is influenced by a smaller number of larger changes.

The registry defines PANSS Total Score as ranging from 30 to 210 and names the endpoint as change from Day 1 to Day 42, final visit, or withdrawal. It does not state which assessment was used for each participant, how a change was calculated when Day 42 was unavailable, or what analysis population was used. Those details matter because the chosen assessment and included participants determine the summary being estimated.

What does standard deviation tell the reader?

In general, a standard deviation describes the spread of individual values around a mean. For a change endpoint, it describes variation in the participant-level change scores rather than uncertainty in the mean itself. A confidence interval, when reported, instead provides a range of values compatible with the data and specified statistical procedure. Both help characterize an estimate, but they answer different questions. Neither a standard deviation nor a confidence interval for the primary endpoint is reported in the registry record.

Precision depends on the amount of information available and the variability of the measurements. The smaller Day 42 count relative to the baseline count makes it especially important to know which participants contributed follow-up data and how missing measurements were handled. The record gives the counts but does not report the analysis needed to quantify precision.

Why does the single-group design matter?

In general, a within-group change is not the same estimand as a difference between treatment groups. A single-group design can describe change among participants receiving the study drug, but it cannot directly estimate how that change differs from a control group's change. Because this study is listed as single-group, with allocation NA and no masking, the record does not contain a randomized between-group contrast. It would be inappropriate to interpret a pre-to-post difference as a controlled treatment effect.

Open-label means treatment was not masked according to the registry. In general, knowledge of treatment can affect expectations, assessment, reporting, or care. This is relevant to interpretation of symptom scales, but the record does not describe any specific bias assessment or mitigation procedure.

What do the planning illustrations represent?

The page includes calculated sample-size illustrations based on an observed effect. The stated assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. These are planning illustrations, not the trial's own design or observed power. This study is recorded as single-group, so the two-arm illustration does not describe the enrollment plan shown in the registry. No sample-size justification for the trial is reported in the registry record.

In general, a planning calculation estimates the number of participants that might be needed under chosen assumptions to detect a specified effect with a chosen power. It is conditional on assumptions about the effect, variability, allocation, and analysis. An illustration based on an observed effect should not be treated as a validation of that effect, nor as evidence that the completed study had a particular probability of finding a result.

What is not established by the posted analysis information?

The record lists 3 outcome measures and 0 analyses. It does not report a statistical analysis plan, an interim analysis, a hypothesis test, an adjustment for multiple outcomes, a model for the primary endpoint, or a confidence interval. The registry record also does not state whether the primary endpoint was analyzed as a mean change among observed cases or by another method. These omissions prevent a detailed reconstruction of the analysis. The endpoint's name and dispersion label identify intended summaries, but they are not substitutes for posted estimates and methods.

In general, results should be interpreted together with their estimate, uncertainty, analysis population, and handling of incomplete observations. Here, those outcome-analysis details are not reported in the registry record. The tables and plots on this page should be read as visual or planning aids where applicable, not as a source of unreported trial outcomes.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures and 0 analyses. The primary outcome is change in PANSS Total Score; the secondary outcome list contains Clinical Global Impression - Severity of Illness (CGI-S) wording twice. The record does not explain whether those repeated entries correspond to distinct assessments or time points, and it does not report a hierarchy among the outcomes or a procedure for controlling multiplicity.

In general, when several outcomes or analyses are examined, the chance of finding at least one apparently notable result can increase unless the analysis plan addresses the number and relationship of tests. A prespecified primary endpoint and clear secondary-outcome procedures can help readers understand which findings are confirmatory and which are exploratory. The registry record does not report those procedures or any test results, so no claim about multiplicity adjustment can be made.

For missing data, the endpoint description says there were 28 participants at baseline and 17 at Day 42, with the difference attributed to withdrawal or termination during the study. It also defines the measurement window as baseline to Day 42, the final visit, or withdrawal. The record does not state why individual participants withdrew, whether their withdrawal assessments were available, how missing values were handled, or which participants were included in the analysis.

In general, missing follow-up measurements can affect both the estimate and its uncertainty, particularly if the availability of a measurement is related to a participant's outcome. Without a reported method and analysis population, the reader cannot assess that issue for this study. The registry record also does not report sensitivity analyses or other checks of how conclusions might change under different assumptions about missing measurements.

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: seizure (3.6%).

The registry lists a Seroquel XR group with 28 participants at risk. It records 1 serious adverse event and 14 other adverse events. The top serious adverse-event term is listed as seizure at 3.6%. These entries are descriptive summaries in a single-group study; they do not provide a comparison with an untreated or alternative-treatment group.

The record does not give additional detail about the timing, duration, outcome, or treatment relationship of the serious event. It does not establish from the summary whether the seizure term refers to the serious event count, and it does not provide a participant-level listing. The deaths entry is not reported in the registry record.

In general, counts of adverse events depend on how events are defined, collected, and coded, as well as the number of participants observed and the duration of observation. A percentage attached to a term should be interpreted using the registry's event definitions and denominator; the record does not provide further explanation of the calculation. The study summary describes planned dosing up to 600 mg once a day for 42 days, but the posted safety entries do not establish comparative risk or a causal relationship. They should be read alongside the limited follow-up and the absence of a control group.

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

This record documents a Phase 3, open-label, single-group study of oral quetiapine in adults with schizophrenia. It identifies a primary endpoint—mean change in PANSS Total Score from baseline to Day 42, final visit, or withdrawal—and gives a definition of the scale and a criterion describing a decrease considered better. It also records enrollment, follow-up counts, and limited adverse-event summaries.

What it does not provide is the numerical primary endpoint result. There is no reported mean change, standard deviation, confidence interval, or analysis result. The record therefore cannot show how much the score changed, how variable participant changes were, or how precisely the average was estimated. It also does not report the number of participants who met the stated decrease criterion.

Even a posted before-and-after change would not, in a single-group design, establish what would have happened without treatment. The open-label design and the lack of a comparator mean that time-related changes and other influences cannot be separated from treatment effects using a controlled contrast. The registry record does not report analyses that address those issues.

The difference between the baseline and Day 42 participant counts is relevant to interpretation, but the record does not explain individual withdrawal reasons or missing-data methods. The status is terminated, with no reason reported in the registry record. Safety entries are similarly descriptive and do not establish a comparative risk estimate. The appropriate reading is therefore limited: the record describes the study question and some design and safety details, but does not report enough outcome analysis to judge the magnitude or precision of change in PANSS scores.

13. Why This Trial Matters Statistically

This study illustrates why a clear outcome definition is not the same as a complete results report. The registry specifies a continuous primary endpoint, its time frame, the scale range, and the intended summary as mean change with standard deviation. Those details help identify the question the study set out to address. But without the numerical estimate and its uncertainty, readers cannot evaluate the observed endpoint data.

It also highlights the distinction between change within a group and a comparison between groups. The record describes a single-group, open-label design, so the primary measure is a within-group change rather than a randomized contrast. In general, that design distinction affects which scientific claims can be supported, regardless of how a change score is summarized.

The baseline and Day 42 counts make analysis populations and missing measurements important. The registry explains that withdrawals or terminations account for the count difference, but does not report the handling of those observations. This is a reminder that counts at each assessment are not enough to reconstruct an analysis: readers also need to know which participants contributed data and how unavailable measurements were treated.

Finally, the sample-size material is explicitly a planning illustration based on an observed effect, with two-arm assumptions that do not match the registry's single-group design. Such illustrations can be useful for understanding how planning assumptions affect sample size, but they should not be confused with the trial's design, an observed power calculation, or evidence that an outcome was statistically established. The distinction is especially important when the registry record does not report an endpoint analysis.

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 of the posted record is that it does not report a numerical result or analysis for the primary PANSS endpoint. Although the registry identifies the measure, time frame, and intended summary, it provides no mean change, standard deviation, confidence interval, or test result. The clinical magnitude and statistical precision of the endpoint therefore cannot be assessed from this record.

The study had no comparator group and was open-label. The record describes a single-group design with allocation marked NA and masking marked none. Consequently, it does not provide a randomized estimate of how change differed from a control condition, and it cannot separate change over time from other possible influences.

Follow-up counts also limit interpretation. The endpoint description reports 28 participants at baseline and 17 at Day 42, attributing the difference to withdrawals or terminations. The record does not report the reasons, the availability of withdrawal assessments, the analysis population, or the method used for missing observations. It also does not report sensitivity analyses.

The study status is terminated, but the reason is not reported in the registry record. The statistical analysis plan, sample-size justification, interim analyses, multiplicity procedures, and analysis methods are not reported in the registry record. The safety summary includes limited event counts and a listed serious term, but does not give further event-level detail; deaths are not reported in the registry record. These limitations make the posted information useful for understanding the study's design and recorded outcomes, but insufficient for a complete assessment of efficacy or comparative safety.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Seroquel XR in Adults With Schizophrenia — NCT00852631.
• Registry record last updated 2012-07-17; status last verified 2012-05.
• Results first posted 2012-07-17.
• 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 NCT00852631, titled Seroquel XR in Adults With Schizophrenia, as a Phase 3, open-label, multicentre, single-group study sponsored by AstraZeneca. It lists 28 participants enrolled, a start date of 2009-02, a primary completion date of 2010-05, and a status of terminated. The reason for termination is not reported in the registry record.

The primary endpoint was change in PANSS Total Score from Day 1 to Day 42, final visit, or withdrawal. The record notes 28 participants at baseline and 17 at Day 42. It does not report a numerical endpoint result or analysis. The safety summary lists 1 serious adverse event and 14 other adverse events among 28 at risk; seizure is listed at 3.6% among the top serious terms. Deaths are not reported in the registry record.