O12.3. EFFECTS OF FINGOLIMOD, A POTENT ANTI-INFLAMMATORY AGENT, ON BRAIN STRUCTURE, FUNCTION, AND SYMPTOMS IN SCHIZOPHRENIA

New medications with novel targets are needed for schizophrenia. Several lines of evidence indicate that inflammatory processes including aberrant lymphocytic activity may be related to the pathophysiology of this illness. These data suggest that agents with anti-inflammatory actions, including modulation of lymphocytes and their inflammatory substrates, may prove to be efficacious for schizophrenia. Fingolimod is a powerful anti-inflammatory agent that is used in the treatment of relapsing multiple sclerosis. It is a sphingosine-1-phosphate (S1P) receptor modulator that decreases circulating lymphocytes through sequestration in lymph tissues. In addition, evidence suggest that it stimulates oligodendrocytes and may enhance white matter integrity. The purpose of this study was to assess the effects of fingolimod in schizophrenia. Subjects with schizophrenia (N=40) were recruited through the Indiana University Psychotic Disorders Programs and randomized 1:1 in a double-blind, eight-week clinical trial of fingolimod 0.5 mg/day and placebo. Circulating total lymphocytes were determined and effects were assessed on symptoms (PANSS), cognition (BACS), plasma cytokines, white matter integrity (DTI) and cortical connectivity (resting fMRI). Results revealed a significant decrease in lymphocytes in subjects taking fingolimod versus placebo (treatment x time; F = 61.2, p < 0.001). Fingolimod treated subjects had a mean maximal drop in lymphocytes from baseline of 79.2% with all fingolimod treated subjects experiencing decrements greater than 60%. There was a trend toward higher mean skeletal fractional anisotropy (FA) post-treatment in the fingolimod group. Within the fingolmiod group, there were significant or trend-level correlations between FA increase and decrease in lymphocytes in the genu and body of the corpus collosum and the right superior longitudinal fasciculus. There were also significant group-by-visit interactions in connectivity of left prefrontal cortical (PFC) seeds with clusters in the cerebellum, driven by higher PFC-cerebellum connectivity following fingolimod treatment. There were no improvements (treatment x time) in PANSS total (F = 0.66, p= 0.52), any of the PANSS subscales, or BACS composite score (F = 0.54, p = 0.44). Serious side effects were not observed, and a full safety report will be provided. Fingolimod produced a strong anti-inflammatory response with substantial reductions in circulating lymphocytes in all treated subjects. Brain effects were observed. However, this response was not accompanied by improvements in symptoms or cognition. These data suggest that fingolimod’s target of S1P modulation and robust anti-inflammatory warrant further investigation in schizophrenia.