M197. SEASONAL ANTIPSYCHOTICS IN SCHIZOPHRENIA: OUTCOMES IN NATURALISTIC SETTINGS (SEASONS STUDY) OBSERVATIONAL RETROSPECTIVE MULTICENTRE CANADIAN STUDY ON 3MONTH-FORMULATION OF LONG-ACTING INJECTABLE PALIPERIDONE PALMITATE

Abstract Background The 3 month-formulation of long-acting injectable paliperidone palmitate (PP3M) is available in Canada since 2016. However, there are still limited data on its use in real life setting. Methods This ongoing study retrospectively reviews the use of this formulation in 6 centers across Canada (targeted n=250 patients). Data on PP3M use (dosage, duration of exposure, reasons for initiating PP3M and stopping it, if applicable) are recorded, as well as its clinical impact (hospitalizations, global severity of illness as measured by Clinical Global Impression Scales), the main outcome variable being discontinuation of PP3M. Results Preliminary data are available for the first 35 patients coming from 3 participating centers. 31/35 are men, on average 35 years old, Caucasian (25/35), exposed to antipsychotics for an average of 7 years (sd 2 yrs) with an average 2-year exposure to the 1-month formulation of long-acting injectable paliperidone palmitate (PP1M). 21/35 had also at least one concomitant disorder (some may be combined), such as substance use disorder, personality disorder or anxious disease, and 10/35 were under a court treatment order. Clinical Remission (as defined as a CGI S score equal or less to 3) was maintained in 27/35 subjects over an average of 14 months (sd 9 months) of PP3M. However, 8 patients stopped their treatment dues to compromise stability (2 patients), side effects (2 patients: somnolence, 1 patient: pain discomfort at site of injection) or loss to follow-up (3 patients). Discussion In this Canadian study, preliminary observations in real life settings suggest that PP3M may be an interesting option for patient previously stabilized on PP1M, although the number of treatment cessations might suggest that the clinical effectiveness of PP3M vs. PP1M may not be similar in all subjects.