An existing drug primarily used to treat rheumatoid arthritis could offer a significant new treatment avenue for individuals battling difficult-to-treat depression, a recent study suggests.
Researchers have for the first time explored whether tocilizumab, an anti-inflammatory medication, could alleviate symptoms in patients unresponsive to standard antidepressant therapies.
Current drug treatments for depression predominantly target brain chemicals such as serotonin, norepinephrine, and dopamine, yet approximately one in three individuals find no relief from these conventional approaches.
The investigation, involving 30 participants with moderate-to-severe depression, yielded early evidence that tocilizumab may reduce depressive symptoms, combat fatigue and anxiety, and improve overall quality of life.
This research builds on findings that roughly a third of people with depression exhibit signs of inflammation in their blood, suggesting their condition could be linked to an overactive immune system.
This offers a promising alternative pathway for those for whom existing treatments are ineffective.
Other studies point to higher levels of inflammatory proteins called cytokines in depression, including interleukin 6 (IL-6).
Researchers at the University of Bristol wanted to see whether symptoms could improve in people with inflammation-related depression by blocking the IL-6 pathway.
The trial split the participants into two with half given tocilizumab and the rest a placebo.
The findings suggest the participants who received tocilizumab seemed to experience greater improvements over time compared to those given a placebo.
Senior author Professor Golam Khandakar, from the University of Bristol, said: “This work represents an important milestone in the development of new treatments for depression, especially difficult-to-treat depression, which affects millions of people in the UK alone.
“This is one of the first randomised controlled trials to test immunotherapy for depression, the first to test IL-6R as the treatment target, and the first to use a targeted approach to select patients most likely to benefit, and to show that it works.”
Lead author Dr Eimear Foley added: “Depression is estimated to affect around 10% to 20% of people worldwide during their lifetime, yet for many patients current treatments do not work well enough.
“Our study moves us closer to more tailored depression care, where treatments are chosen to better fit a person’s biology.
“This will help us to provide the right treatment to the right patients at the right time.”
The next step will be to conduct a large-scale phase III randomised control trial that will provide definitive evidence to enable doctors to prescribe immunotherapy for depression.
– The study, Interleukin 6 as a treatment target for depression: a proof-of-concept randomised clinical trial’, is published in the journal JAMA Psychiatry.
