TocilizuMab discontinuAtion in GIant Cell Arteritis

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)