PRE-EXPOSURE PROPHYLAXIS WITH TIXAGEVIMAB/CILGAVIMAB: SINGLE CENTRE EXPERIENCE IN A COHORT OF RHEUMATIC PATIENTS

ABSTRACT

BackgroundVaccination against SARS-CoV2 had a critical role in the fight against COVID19 pandemic.A weaker humoral response to COVID19 vaccine has been found in rheumatic patients treated with Rituximab (RTX) or Mycophenolate Mofetil (MMF)[1]. Despite the evidence that anti-SARS-CoV-2 mRNA vaccines can elicit a T-cell response [2], some data show that even the cellular immunity could be impaired in rheumatic patients [3] but COVID19 serology is the only parameter that is feasible to measure in daily practice.Tixagevimab+cilgavimab are two human-derived monoclonal antibodies administered parenterally and authorized by regulatory agencies in February 2022 for pre-exposure prophylaxis (PrEP) against COVID19 from different virus variants in fragile patients.ObjectivesTo demonstrate safety and effectiveness of tixagevimab+cilgavimab.MethodsPatients with autoimmune rheumatic diseases undergoing immunosuppressive treatment with RTX or MMF during the vaccination campaign were enrolled between April and June 2022. All patients must have anti-spike antibody levels below the protective threshold (defined by anti-spike IgG titre <250 BAU/ml) after receiving at least 2 vaccine doses.Patients were monitored with a questionnaire every month about COVID19 symptoms (including respiratory and gastrointestinal symptoms, anosmia and ageusia, skin rash and potential contact with COVID19+ subjects) and were checked for anti-spike and anti-nucleocapside antibodies titres every 2 months for a total of a 6 month follow-up. MMF dose was reduced at 1 g/die at the time of vaccine administration.ResultsFifteen patients were enrolled 9 participants had a connective tissue disease (CTD;1 dermatomyositis, 3 anti-syntethase syndrome, 4 systemic sclerosis, 1 systemic lupus erythematosus) and 6 had vasculitis (all granulomatosis with polyangiitis). 12 of them received RTX in the preceding 12 months and 3 were taking MMF.About safety, the therapy was very well tolerated and only 4 patients (26%) reported a non-severe adverse event in the 2 weeks following drug administration (2 myalgia, 1 headache, 1 fatigue), none of them requiring hospitalization nor pharmacologic treatment.Regarding effectiveness, 3/15 patients contracted SARS-Cov2 infection (20%) with mild symptoms and no need for hospitalization nor oxygen therapy. Only 1 of them received an antiviral drug (nirmatrelvir+ritonavir). All infected patients had a CTD diagnosis. No significant correlation was observed between the type of rheumatic disease and the risk of infection or response to tixagevimab+cilgavimab.ConclusionNone of our patients developed severe adverse events after tixagevimab+cilgavimab administration and, among the 3 SARS-CoV2 infected patients, none required hospitalization nor oxygen therapy.We conclude that in our experience tixagevimab+cilgavimab is a safe and useful complementary immunization strategy to vaccination for COVID19 prophylaxis.These data will be implemented in a larger study, comprehending various immunocompromised patients from several departments.References[1] Furer et al., Ann Rheum Dis, 2021[2] Mangalakumari et al., Nat Rev Immunol, 2020[3] Picchianti-Diamanti et al., Front Immunol, 2021Charateristic of the cohortIdentificativeAgeDiagnosisRTX/MMFSARS-CoV2 InfectionHospitalizationAntiviral drugs180SScMMF-//270ASSDRTX+nono370ASSDRTX+noyes452GPARTX-//551GPARTX-//649SSc+SSjRTX-//768SScMMF-//847LESRTX-//964ASSDRTX-//1068GPARTX-//1123GPARTX-//1258DMRTX+nono1361SScMMF-//1475GPARTX-//1569GPARTX-//Figure 1.AcknowledgementsNIL.Disclosure of InterestsNone Declared.