Overview
- The University of Bristol–led trial, which was published 20 May 2026 in JAMA Psychiatry, randomized 30 adults with difficult‑to‑treat depression and repeated CRP elevation to a single tocilizumab infusion (n=14) or saline placebo (n=16).
- By four weeks the tocilizumab group showed larger, clinically meaningful improvements in overall depression scores, fatigue, anxiety, and quality of life and a higher remission rate (54% versus 31%) compared with placebo.
- The study was a short proof‑of‑concept trial with too few participants and a brief follow‑up to rule out chance, so results were numerically encouraging but not definitive for statistical significance.
- Tocilizumab is already approved for rheumatoid arthritis and cytokine release syndrome, which eases repurposing but also raises safety concerns such as infection risk that require evaluation in larger, longer trials before clinical use for depression.
- Researchers say the trial supports a biomarker‑guided approach using repeat hs‑CRP to identify the roughly one‑third of patients whose depression is linked to low‑grade inflammation and who might benefit from targeted IL‑6 blockade in future phase III studies.