Overview
- The University of Bristol randomized proof‑of‑concept trial, published Wednesday, May 20, 2026, found that a single infusion of tocilizumab produced larger clinical improvements at four weeks for people with difficult‑to‑treat depression who had persistent low‑grade inflammation.
- Thirty adults were enrolled; 14 received tocilizumab and 16 received a saline placebo, all stayed on their antidepressants and were assessed at one, two and four weeks after the single infusion.
- No clear benefit appeared at one or two weeks, but by week four the tocilizumab group showed bigger gains in depression scores, fatigue, anxiety and quality of life, with remission in about 54% versus about 31% in the placebo group.
- The study was small, short and underpowered, so results are preliminary and cannot prove the treatment works; tocilizumab is an immunosuppressive drug that carries infection and safety risks that need careful evaluation in larger trials.
- About one in three people with depression have elevated inflammatory markers such as IL‑6 or CRP, and this trial is among the first randomized tests of IL‑6 receptor blockade that could enable biomarker‑guided, personalized treatment if confirmed in phase III studies.