A common arthritis drug may offer a new treatment pathway for the millions of people with depression that doesn't respond to standard therapies.
A four-week proof-of-concept trial tested tocilizumab, an anti-inflammatory drug used for rheumatoid arthritis, on 30 patients with moderate-to-severe depression who had not responded to antidepressants. All participants had signs of inflammation in their blood.
Tocilizumab treatments improved depression scores more than a placebo. (Foley et al., JAMA Psychiatry, 2026)
Results showed those receiving tocilizumab had significant improvements in depression severity, fatigue, anxiety, and quality of life. By the end of the study, 54% of the tocilizumab group were in depression remission, compared to 31% of the placebo group.
Lead researcher Golam Khandakar from the University of Bristol said this work marks an important milestone in developing new treatments for difficult-to-treat depression.
The drug targets the interleukin 6 (IL-6) pathway, a protein linked to inflammation. Patients with higher initial inflammation markers responded best to the treatment.
Since tocilizumab is already FDA-approved and safe for human use, the path to regulatory approval for depression could be faster. The trial was small and did not reach statistical significance, but researchers say it provides enough evidence to warrant larger, longer studies.
The research was published in JAMA Psychiatry.