Immune-Targeted Therapies for Depression: Current Evidence for Antidepressant Effects of Monoclonal Antibodies

Importance: Increasing evidence suggests a potential role of immune-modulatory drugs for treatment-resistant depression. This scoping review explores the emerging evidence regarding the antidepressant effects of monoclonal antibodies (mAbs), a relatively newer class of immune therapeutics with favorable safety profile. Observations: PubMed was searched up to November 2023 for English publications addressing the antidepressant effects of mAbs, including meta-analyses, randomized controlled trials, open-label, single-arm studies, and case series. Several mAbs have shown potential antidepressant effects, but most studies in primary inflammatory disorders included patients with mild depression. Only infliximab and sirukumab were directly examined in individuals with primary depression. mAbs that do not require laboratory monitoring, such as ixekizumab and dupilumab, could hold potential promise if future studies establish their safety profile regarding suicide risk. Conclusions and Relevance: The use of several mAbs for the treatment of primary inflammatory disorders has been associated with improvement of comorbid depressive symptoms. Given their unique mechanisms of action, mAbs may offer a new hope for depressed patients who do not respond to currently available antidepressants. Further research addressing individuals with more severe depressive symptoms is essential. Direct examination of antidepressant effects of mAbs in people with primary depressive disorders is also crucial to refine their clinical use in the treatment of depression.