Justification And Evaluation of Baricitinib Plus Corticosteroids Versus corticosteroiDs Alone in pOlymyalgia RhEumatica

Polymyalgia rheumatic (PMR) is an inflammatory rheumatic disease affecting the elderly. The diagnosis is based on established ACR/EULAR classification criteria. The activity of the disease is evaluated using the PMR-AS, a disease activity score based on morning stiffness, ability to elevate the upper limbs, physician's global disease assessment and pain assessment measured by the patient using VAS, and the C-reactive protein (CRP) level. The PMR-AS-CRP (PMR-AS) is considered as relevant to define disease activity (low activity \17), flare (\>10), remission (\20 increase, 10≤ PMR-AS ≤20: stable dose) \[10-12\]. Long term low-dose glucocorticoid (GCs) (prednisone or prednisolone started at 12.5 to 25 mg/day progressively tapered) is the mainstay of the treatment. But comorbidities in PMR are due to GCs and 30% of the patients underwent a relapse when tapering GCs. Today, the physicians do not know what is the best duration and the best dosage of GCs. The international recommendation suggests to start prednisone at a dose between 12.5 to 25 mg, to be at 10 mg at 1 or 2 months, and then to decrease slowly. The treatment is generally ordered for 6-18 months but it is possible to try a shorter treatment duration when patients have been previously treated with GCs or in case of comorbidities. The TENOR study, a phase 2 study, demonstrated efficacy of tocilizumab as first line treatment in PMR and its ability to spare GCs. The Semaphore study confirmed the usefulness of tocilizumab in corticodependent forms and demonstrated its efficacy. Another IL-6 inhibitor, sarilumab was authorized for the treatment for polymyalgia rheumatic in adult patients with inadequate response to corticosteroid or relapsing disease but is not reimbursed in France. Baricitinib is an oral selective JAK inhibitor of JAK1 and JAK2 with