LB0003 WITHDRAWING METHOTREXATE AFTER BOTH VERSUS ONLY SECOND DOSE OF THE ChAdOx1 nCoV-19 VACCINE IN PATIENTS WITH AUTOIMMUNE INFLAMMATORY ARTHRITIS: TWO INDEPENDENT RANDOMIZED CONTROLLED TRIALS (MIVAC I AND II)

Background Pausing methotrexate (MTX) for two to four weeks, improved immunogenicity of influenza vaccination in patients with rheumatoid arthritis (RA), albeit a risk disease flare (1). This guided the framing guidelines on MTX withdrawal COVID-19 (2). However, evidence is limited observational studies only. Objectives To compare efficacy and safety holding after each (MIVAC 1) only second dose II) ChAdOx1 vaccine versus continuation randomized controlled trials (RCTs). Methods Two single centre, investigator-blinded, RCTs were conducted RA or Psoriatic (PsA) stable doses without prior (CTRI reg. no. MIVAC I: CTRI/2021/07/03463 & II: CTRI/2021/07/035307). In I, unvaccinated randomised (1:1) hold continue weeks vaccine. II included who had continued during first 2 dose. The primary outcome both was anti-Receptor Binding Domain (RBD) antibody titres measured (per protocol analysis). Secondary rate, defined as an increase activity scores (DAS28/cDAPSA) physician intent hike DMARDs. Results 250 1 178 due exclusions, 158 157 eligible analysis respectively (Figure 1). median anti-RBD significantly high group [2484 (1050-4388) 1147(433-2360), p=0.001] but rate higher [20 (25%) 6(8%) p=0.005] compared group. [2553 (1792-4823) 990 (356-2252), when there no difference between groups [9(11.8%) 4(7.9%), p=0.15] (Table Since parallel similar population, arms across flare. There [p=0.2] groups. 29(36.25%) reported (19 either dose, 10 doses) where 9(11.84%) (P <0.001). Table 1. Baseline demographics key results Variable I Hold Continue P value N=80 N=78 N=76 N=81 Age† 48 (38-53.3) 49 (39-59) 0.19 53 (42.3-59) 53(50-62) 0.14 Female (%) ‡ 73 (91.3) 75 (96.2) 0.33 65 (85.5) 70 (86.4) >0.99 69(86.3) 69 (93.2) (85.6) 80 (87.7) PsA 11(13.8) 6 (8.1) 0.31 (7.9) (1.2) 0.057 DAS28† 2.7 (2.4-3.2) 2.6 (2-3.3) 0.6 2.7(2.3-3.4) 2.8 (2.1-3.5) 0.78 cDAPSA † 2(3-4.5) 2.5(1.3-3.8) 0.46 3(2.8-3) 3 0.15 Prednisolone 29 (36.3) 23(31.1) 0.4 24(31.6) 26 (32.1) mg/week† 17.5 (10-25) 15 (10-20) (9.4-25) 17.5(7.5-25) 0.92 Anti- RBD post (IU/mL) 2484 (1050-4388.8) 1147.5 (433.5-2360.3) <0.001 2553.5 (1792.5-4823.8) 990.5 (356.1-2252.5) Flare (N%) Post 20 (25) (8) 0.005 NA 19 (23.8) 10(13.3) 0.1 9 (11.8) 4 All per population. †Median (interquartile range): Mann Whitney U test. N (%): Fisher Exact test . Bolded if p<0.05. Conclusion Holding yields continuing MTX. Comparing trials, appears be non-inferior lesser References [1]Park JK et al. Clin Rheumatol. 2020 Feb; 39(2):375-379. [2]Curtis JR, Arthritis Rheumatology. 2021 Oct;73(10): e60-75. Acknowledgements Acknowledgments all participating investigators, their families Disclosure Interests Anu Sreekanth: None declared, Teny Skaria: Sneha Joseph: Rashwith Umesh: Manju Mohanan: Aby Paul: Sakir Ahmed Speakers bureau: received honorarium speaker from Pfizer, Dr Reddy’s, Cipla, Novartis unrelated this Comment, Pankti Mehta: Seena Oomen: Janet Benny: Justin George: Anagha Paulose: K Narayanan: Sanjana Anuroopa Vijayan: Kaveri Nalianda: Padmanabha Shenoy: declared