Prophylaxis with tixagevimab/cilgavimab is associated with lower COVID-19 incidence and severity in patients with autoimmune diseases

To describe the clinical efficacy of tixagevimab/cilgavimab in pre-exposure prophylaxis in patients at risk of severe COVID-19 and unresponsive to vaccination (anti-SARS-CoV-2 antibodies <260 BAU/mL) in rheumatology.In this multicenter observational study we included patients with autoimmune or inflammatory diseases who received a pre-exposure prophylaxis by tixagevimab/cilgavimab between December 2021 and August 2022. The endpoint was incidence and severity of COVID-19.Tixagevimab/cilgavimab was administered to 115 patients, median age 62 years (52-71), with chronic arthritis (n = 53), connective tissue disease (n = 38) or vasculitis (n = 11). Main background immunosuppressants were rituximab (n = 98), corticosteroids (n = 62, median dose 5mg, CI95% 5-8 mg) and methotrexate (n = 48). During a median follow-up of 128 days (93-173), COVID-19 occurred in 23/115patients (20%), Omicron identified for the 8 genotyped patients. During study period, the average weekly incidence was 1071/100.000 inhabitants in Ile-de-France vs. 588/100.000 in our patients. Patients who received a 2-injections regimen had a lower risk of infection than with a single injection (16/49, 33% vs. 5/64, 8%, p = 0.0012). The COVID-19+ patients did not differ from uninfected patients concerning age, comorbidities, underlying rheumatic disease, immunosuppressant. All COVID-19 were non-severe. The tolerance of injections was excellent.In a population with autoimmune or inflammatory diseases at risk of severe COVID-19 unresponsive to vaccination, pre-exposure prophylaxis by tixagevimab/cilgavimab was associated with lower incidence of COVID-19 and no severe infection to report.