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Adjunctive tocilizumab may improve cognition in schizophrenia

Tocilizumab may be a potential adjunctive treatment for cognitive impairment in individuals with schizophrenia, according to recent findings.

To determine efficacy of adjunctive tocilizumab, a humanized interleukin-6 receptor monoclonal antibody, for cognitive impairment in individuals with schizophrenia, Brian J. Miller, PhD, MPH, of Georgia Regents University, Augusta, Georgia, and colleagues conducted an 8-week open-label trial. The trial was conducted with Institutional Review Board approval and an Investigational New Drug waiver from the FDA. Study participants were aged 18 to 55 years, had a DSM-IV diagnosis of schizophrenia or schizoaffective disorder, were taking a nonclozapine antipsychotic, had no psychiatric hospitalizations in the past 3 months, and were on stable psychotropic medications for at least 1 month.

Participants (n = 5) received 4 mg/kg of tocilizumab at baseline and 4 weeks. Psychopathology, cognition, and fasting serum high-sensitivity C-reactive protein and cytokine levels were assessed at baseline and weeks 2, 4 and 8.

Infusions were tolerated with no clinically significant adverse events, according to researchers.

Brief Assessment of Cognition in Schizophrenia (BACS) scores for verbal fluency significantly improved at 4 weeks, as did digit symbol encoding at 2, 4 and 8 weeks, and composite score at 4 and 8 weeks.

Psychopathology scores and fasting serum high-sensitivity C-reactive protein and cytokine levels did not significantly change.

Baseline immune measure did not predict changes in cognition. This may be due to the small sample size and that baseline IL-6 levels were undetectable in the majority of the cohort, according to researchers.

“Our findings suggest that tocilizumab may be a viable adjunctive treatment for cognitive impairment in schizophrenia, although safety and cost (approximately $1,000 per 4 mg/kg dose) are important considerations regarding its clinical utility,” Miller and colleagues wrote. “Given the serious potential adverse effects due to immunosuppression, which include life-threatening infections, ulcers and malignancy, use of this medication required a formal risk evaluation and mitigation strategy. An important strength of our study is that, unlike nonsteroidal anti-inflammatories, tocilizumab has no relevant off-target (ie, nonimmune system) effects.” – by Amanda Oldt

Disclosure: Miller reports receiving grant support for this study from the American Psychiatric Association, receiving grant support from the NIMH, research support from the NIH Clinical Loan Repayment Program and Georgia Regents University, honoraria from Psychiatric Times, and speaker fees for lectures from the University of Nevada, Reno, and Emory University, in the past 12 months. Please see the full study for a list of all authors’ relevant financial disclosures.