The proposed study aims to establish the feasibility and safety of subcutaneous tocilizumab, a monoclonal antibody (mAb) against interleukin (IL)-6 receptor, in adults with Major Depressive Disorder (MDD) and evidence of peripheral immune activation. IL-6 is a pro-inflammatory cytokine implicated in the pathophysiology of depression. The investigators hypothesize that neutralizing peripheral immune signaling via IL-6 receptor blockade with tocilizumab will improve neural and behavioral measures of reward processing. This is an open-label, proof-of concept, trial in which up to N=20 adults with MDD meeting a specific immune enrichment criterion will receive open-label tocilizumab over 8 weeks. A healthy control (HC) group (N=20) will undergo baseline neuroimaging and blood-based biomarker assessment without receiving the study drug to aid interpretation of findings. Blood-based immune markers and brain MRI scans (including task-based reward activation and resting-state functional connectivity) will be assessed at baseline for all participants and again post treatment for the MDD group.
Who can participate
Age range
18 Years – 70 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
For MDD participants:
* Written informed consent;
* Ability to comply with the requirements of the study as determined by the PI;
* Ages 18-70 years;
* Any gender;
* DSM-5 diagnosis of MDD in a current Major Depressive Episode;
* Immune enrichment criterion: elevated monocyte count ≥ 500 cells/μL at screening;
* If patient is on antidepressant medication, they must be on a stable dose for ≥4 weeks prior to treatment;
* SHAPS score ≥20
* If female of childbearing potential, must agree to use of a medically accepted form of contraception, or else agree to abstinence until 6 months after the last dose of study drug;
* Male patients, if heterosexually active with a partner who is female of childbearing potential, pregnant, or breastfeeding, must agree to barrier contraception for the treatment period and for at least 6 months after the last dose of the study drug. Female partners of male participants must use at least one form of highly effective contraception starting at least one cycle prior to male patient study drug initiation until 6 months after the last dose of study drug.
* Meet all MRI safety criteria.
For Healthy Volunteers:
* Written informed consent;
* Ability to comply with the requirements of the study as determined by the PI;
* Ages 18-70
* Any gender;
* No current or past DSM-5 psychiatric disorder;
* Meet all MRI safety criteria.
Exclusion Criteria:
For MDD Participants
* A primary DSM-5 psychiatric diagnosis other than MDD, with the ex…
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Change in ventral stratal activation during reward processing (fMRI)