Deborah Layton, Vicki Osborne, Miranda Davies, Saad Shakir

Background

APs are generally effective but some patients (pts) may stop soon after starting due to poor tolerability. Quetiapine prolonged-release (Seroquel XL©) was developed to improve tolerability and administration via once daily dosing. The Risk Management Plan had a requirement to describe utilisation and monitor safety as prescribed to new XL users in primary care, via Modified Prescription-Event Monitoring (MPEM).

Objectives

A post-hoc analysis to describe common factors associated with stopping XL.

Methods

MPEM uses an observational cohort design. Questionnaires completed by physicians (GPs) collected data on pt demographics, prior medical history (pmh), prior/current medication use, XL exposure and events (incl. reasons for stopping (RFS)) Sep2008-Feb2013. Descriptive statistics described the cohort. Kaplan Meier methods analysed time to stopping in first 12 months after starting. Crude Odds Ratios (OR) and 95%CI) were calculated to explore relationships between stopping and pt characteristics.

Results

Cohort = 13276; 59% (7828) female; median age 43 yrs (IQR 33,55); indication: Bipolar Disorder (30%,3820), Major Depressive Disorder (22%,2844), Schizophrenia (18%,2373) and Other non-licensed (29%,3750). 3753 pts (28% cohort) stopped treatment (10% by day 56; 25% by day 220). There was significant variation by indication (Log rank test p<0.001) – pts with Other non-licensed indications were most likely to stop (31%, 1162). The most frequent non-clinical and clinical RFS were the events: ‘drug ineffective’ (19%, 581/3094) and ‘sedation’ (15%, 269/750). Pts with a pmh somnolence/ sedation vs those without were more likely to stop due to Sedation: OR 3.3 (2.1, 4.9). Naive AP use, a pmh of extrapyramidal symptoms, metabolic syndrome, diabetes, and impaired glucose tolerance appeared to be risk factors for stopping for any reason.

Conclusion

In this study, nearly one third of pts stopped Seroquel XL© <12 months and RFS were varied. Certain pt characteristics may also be associated with a higher risk of stopping. Further work will explore the impact of dosing. This data can help support GPs decisions on prescribing and management to prevent premature treatment cessation.