Rituximab - Immunotherapy for Obsessive-Compulsive Disorder. A pilot study.

Immunological factors may be determinants for some psychiatric disorders, thus immunomodulation may help.

We aim to investigate whether the psychiatric symptoms of treatment-resistant adults diagnosed with obsessive compulsive disorder, are significantly improved after treatment with rituximab. This is a single-site, 20-week, open pilot, add-on treatment as usual, trial, where the patients will be followed for 1 year.

Rituximab will be administered with one single dose of 1000 mg. Investigators will analyse inflammatory and metabolic biomarkers in relation to the primary outcome, treatment response (defined as clinically relevant reduction in the validated measure Y-BOCS). Other outcomes are Clinical Global Impression - Improvement scale (CGI-I) and change in Personal and Social Performance Scale measuring disability.