Beneficial effect of temporary methotrexate interruption on B and T cell responses upon SARS-CoV-2 vaccination in patients with rheumatoid arthritis or psoriatic arthritis.

"Competing interests S.C. has received consultation fees in company-sponsored speaker’s bureau from Amgen, BMS, Eli-Lilly, MSD, Roche, Sanofi and UCB. S. Castañeda is assistant professor of the cátedra UAM-Roche, EPID-Future, Universidad Autónoma de Madrid (UAM), Madrid, Spain. I.G.-A. reports grants from Instituto de Salud Carlos III, during the course of the study; personal fees from Lilly and Sanofi; personal fees and non-financial support from BMS; personal fees and non-financial support from Abbvie; research support, personal fees and non-financial support from Roche Laboratories; research support from Gebro Pharma; non-financial support from MSD, Pfizer and Novartis, not related to the submitted work. The rest of the authors do not declare conflicts of interest in relation to this work."

"We would like to thank the patients for their willingness to participate in research and Manuel Gómez Gutiérrez for reviewing this manuscript. We also thank the rest of the members of Rheumatology Department, Eva G. Tomero, Ana M. Ortiz, Alicia Humbría, María Ahijon, Cristina Valero-Martínez, Amada Beltrán, Juan P. Baldivieso and Maryia Nikitsina, for their collaboration in the recruitment of patients. This study was funded by Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) (Grant no. PI21/0147 to SC, PID-2020-120412RB-I00 and PDC2021-121797-I00 to F.S.-M.) and co-funded by European regional development fund (ERDF) “A way to make Europe”, and also by REACT-EU-INMUNOVACTER-CM, P2022/BMD7209-INTEGRAMUNE from Comunidad Autónoma de Madrid and La Caixa Health Research Grant LCF/PR/HR23/52430018. P.M.-F. has been funded by a Rio-Hortega grant CM22/00076 from the Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) and co-funded by the European Regional Development Fund (ERDF) “A way to make Europe”. A.T.-M. has been funded by the program RICORS (Red de Enfermedades Inflamatorias; RD21/0002/0027) from the Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) and co-funded by the European Regional Development Fund (ERDF) “A way to make Europe”. ER-V has been funded by a Rio-Hortega grant CM19/00149 from the Ministerio de Economía y Competitividad (Instituto de Salud Carlos III) and co-funded by the European Regional Development Fund (ERDF) “A way to make Europe”."

"This is a single-centre, randomised, prospective and investigator-blinded study carried out at a tertiary hospital (Hospital de La Princesa, Madrid, Spain) during the first COVID-19 vaccination campaign. However, the study could not be registered as a randomised clinical trial due to the time pressures of vaccination campaigns, which precluded a complete control of the intervention. To calculate sample size of the study population, we assumed an alpha error of 0.05, a power of 10%, a loss rate of 10% and an expected difference in antibody titres of 14%. Our estimated sample size per group was 68 patients (204 in total). Adult RA or PsA participants were enrolled between March and September 2021. The inclusion criteria were: to be diagnosed with RA or PsA according to ACR/EULAR 2010 or CASPAR criteria, respectively, ≥18 years of age, with stable MTX treatment for at least 6 weeks and willing to participate. Recruited participants were receiving MTX either as monotherapy or combined with other csDMARDs, bDMARDs or tsDMARDs. Exclusion criteria were pregnancy, having other IMID, Guillain-Barre syndrome, demyelinating disease, allergy to any component of the vaccine or having received attenuated or inactivated vaccines in the previous 4 or 2 weeks, respectively. Patients were randomly assigned to one of the three different groups of the study in a 1:1:1 ratio by an independent investigator, who was masked to patients’ evaluations. Randomisation was stratified by sex and age. Randomisation process was concealed from investigators in charge of enrolling and evaluating patients."