Janus Kinase (JAK) Inhibitors Significantly Reduce the Humoral Vaccination Response Against SARS-CoV-2 in Patients with Rheumatoid Arthritis

Objectives Recently, a number of studies have explored the possible attenuation of the immune response by disease-modifying antirheumatic drugs (DMARDs) in patients with rheumatoid arthritis (RA). Our study objective was to investigate the presumed attenuated humoral response to vaccination against SARS-CoV-2 in patients with RA treated with Janus kinase (JAK) inhibitors with or without methotrexate (MTX). The immune responses were compared with controls without RA. Method The humoral vaccination response was evaluated by determining titres of neutralising antibodies against the S1 antigen of SARS-CoV-2. One hundred and thirteen fully vaccinated individuals were included at 6 +1 weeks after second vaccination (BioNTech/Pfizer (69.9%), AstraZeneca (21.2%), and Moderna (8.9%)). In a cross-sectional and single-centre study design, we compared titres of neutralising antibodies between patients with (n = 51) and without (n = 62) medication with JAK inhibitors. Results Treatment with JAK inhibitors led to a significantly reduced humoral response to vaccination (P = 0.004). A maximum immune response was seen in 77.4% of control patients, whereas this percentage was reduced to 54.9% in study participants on medication with JAK inhibitors (effect size d = 0.270). Further subanalyses revealed that patients on combination treatment (JAK inhibitors and MTX, 9 of 51 subjects) demonstrated an even significantly impaired immune response as compared to patients on monotherapy with JAK inhibitors (P = 0.028; d = 0.267). Conclusions JAK inhibitors significantly reduce the humoral response following dual vaccination against SARS-CoV-2. The combination with MTX causes an additional, significant reduction in neutralising IgG titres. Our data suggest cessation of JAK inhibitors in patients with RA in the context of vaccination against SARS-CoV-2.