OA06 Single-centre experience of the use of Rituximab for inflammatory arthritis during the COVID-19 pandemic
Authors: Kimpton James , Bradbury Chloe , Gravell Rhys , Moore Samantha , Buck Pauline , Leandro Maria 
Published: April 2022

Abstract

Background/Aims
There is increasing evidence from large observational cohort studies that rituximab may result in more severe COVID-19 disease and increase the risk of death. There is also concern that rituximab impairs response to the COVID-19 vaccination. We aimed to determine the outcome of patients with inflammatory arthritis treated with rituximab during the current COVID-19 pandemic.

Methods
We conducted a single-centre retrospective observational study of patients with rheumatoid arthritis (RA) or juvenile idiopathic arthritis (JIA) treated with rituximab under follow-up in a dedicated clinic from the start of the COVID-19 pandemic in February 2020 until September 2021. We assessed the outcomes of those with COVID-19 infection and serological response to COVID-19 vaccination in patients tested for SARS-CoV-2 Spike antibodies.

Results
So far, 139 patients have been included (82.0% female, mean age 63.0 [SD 15.6] years). 132 patients had RA and 7 had JIA. 18 patients (12.9%) reported testing positive for COVID-19 infection. Of these, 11 patients (61.1%) were hospitalised. 9 (50%) did not require supplemental oxygen, 2 (11.1%) required supplemental oxygen, 6 (33.3%) required non-invasive ventilation or high-flow oxygen, and 1 (5.6%) required invasive mechanical ventilation. 4 patients (12.2%) died, average number of days from COVID-19 symptom onset to death was 27 (SD 5.2). 8 patients (44.4%) made a full recovery, 6 patients (33.3%) were left with permanent health defects. There was a trend toward higher levels of care in patients who had received more rituximab cycles. Of 21 patients who received both COVID-19 vaccination doses and had COVID-19 serology performed, only 9 patients (42.9%) had positive COVID-19 serology post vaccination. There was a significant difference in the number of days from last infusion to second vaccination dose between those with a positive serological response (median 231.0, IQR [285.0-194.3] days) compared with those with a negative response (median 504.0, IQR [266.0-580.0] days) (p = 0.007, Mann-Whitney U test). Of 3 patients who had not been vaccinated but had previously confirmed COVID-19 infection (positive PCR), only 1 patient had positive COVID-19 serology. Mean duration from positive PCR test to serology test 83.3 (SD 14.4) days. Since February 2020, at least 19 patients (13.7%) paused rituximab or switched to an alternative biologic due to concerns over COVID-19 risk. Of 17 patients that switched, the most common alternative biologics were abatacept (11), baracitinib (3) and sarilumab (2). 5 patients continued rituximab at a reduced dose of 1 gram per cycle.

Conclusion
Given the potential for an increased risk of severity of COVID-19 infection and reduced response to COVID-19 vaccination in patients treated with rituximab, ‘pausing’ or ‘delaying’ it and use of alternative therapies to maintain disease control should be considered. The risks and benefits need to be carefully considered on a case-by-case basis.

Disclosure
J. Kimpton: None. C. Bradbury: None. R. Gravell: None. S. Moore: None. P. Buck: None. M. Leandro: Consultancies; ML has received fees for participating in Advisory Board from Genentech. Grants/research support; ML has received research grant from Roche Basel paid directly to employer, University College London.