Can we stop this arthritis drug without relapse? new trial aims to find out

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Written consent * Diagnosis of GCA, defined by the following criteria: * Age ≥50 years at diagnosis * AND History of ESR ≥50 mm/h OR CRP ≥20 mg/L (optional criterion if temporal artery biopsy (TAB) is positive). * AND at least one of the following clinical criteria: * At least one unequivocal sign of GCA (recent headache, scalp hyperesthesia, jaw claudication, temporal artery abnormality, visual disturbances of ischemic origin) * Clinical sign(s) of polymyalgia rheumatica (PR) * AND at least one of the following criteria during GCA follow-up: * TAB consistent with the diagnosis of GCA (non-necrotizing vasculitis with a mononuclear cell-rich inflammatory infiltrate or presence of granulomas, with or without multinuclear giant cells) * Evidence of temporal artery vasculitis by echo-Doppler of the temporal arteries (unilateral or bilateral halo sign) * Evidence of vasculitis of at least one large vessel by imaging: * angio-CT or angio-MRI: arterial wall thickening (≥2mm for aorta; ≥1mm for supra-aortic trunks and upper extremity arteries, ≥0.6mm for the cephalic artery, …) and/or T1-weighted contrast. * PET: grade 2 or 3\* hypermetabolism of the wall of at least one large vessel (aorta, supra-aortic trunks, cephalic vessels, upper extremity arteries) (\*i.e., arterial SUVmax ≥ liver SUVmax) * GCA in remission for at least 12 weeks before randomisation (remission = absence of symptoms due to GCA AND CRP ≤10 mg/L) * TCZ treatment (IV or SC) or biosimilar initiated 12 to 36 months prior to randomization * TCZ treatment (IV or SC) or biosimilar not interrupted more than 12 weeks in the 12 months prior to randomization * Treatment with subcutaneous TCZ (162 mg/week) or biosimilar for at least 12 consecutive weeks prior to randomization * Treatment with corticoids stopped at least 12 weeks before randomization (hydrocortisone treatment ≤20 mg/day is possible if given at a stable dose for the duration of the study) * Biological workup dating from less than 6 weeks on the day of randomization, showing good tolerance of tocilizumab: * AST and ALT \< 1.5 x upper limit of normal (ULN) * Hemoglobin \>8 g/dL * Platelets \>100 G/L * Neutrophils \>1 G/L * Lymphocytes \>0.5 G/L Exclusion Criteria: * Person who is not affiliated with the national health insurance system * Person subject to a measure of legal protection (guardianship, tutorship) * Person subject to a court order * Patient unable to give consent * Person who does not speak French * Pre-menopausal women (menopause = amenorrhea of more than 12 consecutive months) * Uncontrolled psychotic state * History of drug or alcohol intoxication requiring hospitalization within 12 months prior to randomization * Recent or scheduled surgery within 6 months of randomization * History of organ or hematopoietic marrow transplantation (except corneal transplantation performed at least 12 weeks prior to randomization) * Primary or secondary immune deficiency * Concomitant treatment with any of the following: * Methotrexate, leflunomide, cyclosporin A, azathioprine, mycophenolate mofetil, Janus kinase inhibitors, abatacept, secukinumab, anti-TNF-α, anakinra, ustekinumab, or any other immunosuppressive drug within 12 weeks prior to randomization * Rituximab or other anti-CD20 agent within 1 year prior to randomization * Cyclophosphamide in the year prior to randomization * History of long-term corticosteroid therapy for conditions other than GCA or PPR. (NB: dermocorticoids, inhaled corticosteroids, and corticosteroid joint infiltrations are allowed during the study) * Patient who has previously received ≥3 courses of oral corticosteroids for a disease other than GCA or RRP within 6 months prior to randomization * Ongoing anti-tuberculosis treatment at the time of randomization * Infections: * Current viral hepatitis B or C * Ongoing HIV infection * Severe infection requiring hospitalization within 30 days prior to randomization * Any unstable or poorly controlled condition or disease, acute or chronic, not related to GCA, and considered a contraindication to tocilizumab therapy in the opinion of the investigator * Neoplasia \< 5 years, (except cervical cancer in situ and skin carcinoma, except melanoma, with R0 resection)