ABSTRACT
Background: Patients with systemic lupus erythematosus (SLE) are at an increased risk of infection relative to the general population. We aimed to describe the frequency and risk factors for serious infections in patients with moderate-to-severe SLE treated with rituximab, belimumab, and standard of care therapies in a large national observational cohort. Method(s): The British Isles Lupus Assessment Group Biologics Register (BILAG-BR) is a UK-based prospective register of patients with SLE. Patients were recruited by their treating physician as part of their scheduled care from 64 centres across the UK by use of a standardised case report form. Inclusion criteria for the BILAG-BR included age older than 5 years, ability to provide informed consent, a diagnosis of SLE, and starting a new biological therapy within the last 12 months or a new standard of care drug within the last month. The primary outcome for this study was the rate of serious infections within the first 12 months of therapy. Serious infections were defined as those requiring intravenous antibiotic treatment, hospital admission, or resulting in morbidity or death. Infection and mortality data were collected from study centres and further mortality data were collected from the UK Office for National Statistics. The relationship between serious infection and drug type was analysed using a multiple-failure Cox proportional hazards model. Finding(s): Between July 1, 2010, and Feb 23, 2021, 1383 individuals were recruited to the BILAG-BR. 335 patients were excluded from this analysis. The remaining 1048 participants contributed 1002.7 person-years of follow-up and included 746 (71%) participants on rituximab, 119 (11%) participants on belimumab, and 183 (17%) participants on standard of care. The median age of the cohort was 39 years (IQR 30-50), 942 (90%) of 1048 patients were women and 106 (10%) were men. Of the patients with available ethnicity data, 514 (56%) of 911 were White, 169 (19%) were Asian, 161 (18%) were Black, and 67 (7%) were of multiple-mixed or other ethnic backgrounds. 118 serious infections occurred in 76 individuals during the 12-month study period, which included 92 serious infections in 58 individuals on rituximab, eight serious infections in five individuals receiving belimumab, and 18 serious infections in 13 individuals on standard of care. The overall crude incidence rate of serious infection was 117.7 (95% CI 98.3-141.0) per 1000 person-years. Compared with standard of care, the serious infection risk was similar in the rituximab (adjusted hazard ratio [HR] 1.68 [0.60-4.68]) and belimumab groups (1.01 [0.21-4.80]). Across the whole cohort in multivariate analysis, serious infection risk was associated with prednisolone dose (>10 mg;2.38 [95%CI 1.47-3.84]), hypogammaglobulinaemia (<6 g/L;2.16 [1.38-3.37]), and multimorbidity (1.45 [1.17-1.80]). Additional concomitant immunosuppressive use appeared to be associated with a reduced risk (0.60 [0.41-0.90]). We found no significant safety signals regarding atypical infections. Six infection-related deaths occurred at a median of 121 days (IQR 60-151) days from cohort entry. Interpretation(s): In patients with moderate-to-severe SLE, rituximab, belimumab, and standard immunosuppressive therapy have similar serious infection risks. Key risk factors for serious infections included multimorbidity, hypogammaglobulinaemia, and increased glucocorticoid doses. When considering the risk of serious infection, we propose that immunosupppressives, rituximab, and belimumab should be prioritised as mainstay therapies to optimise SLE management and support proactive minimisation of glucocorticoid use. Funding(s): None.Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license
ABSTRACT
Background/Aims Rituximab is a chimeric type-1 anti-CD20 monoclonal antibody approved by NHS England for refractory SLE. Secondary inefficacy with infusion reactions and anti-rituximab-antibodies occurs in 14% of re-treated patients. Obinutuzumab is a next-generation humanised type-2 anti-CD20 antibody licensed for the treatment of haematological malignancies. Methods We collated data from nine SLE patients receiving off-label obinutuzumab for secondary non-response to rituximab with infusion reactions across six centres (Leeds, Bradford, York, UCL, Birmingham and Nottingham). Disease activity was assessed using BILAG-2004 and SLEDAI-2K and serology in local diagnostic laboratories before, and 6 months after, obinutuzumab 2x1000mg infusions 2 weeks apart alongside methylprednisolone 100mg. Results All patients received concomitant oral immunosuppression and prednisolone. 6/9 received hydroxychloroquine. The median number of rituximab cycles before obinutuzumab therapy was 2.5. Before obinutuzumab 6/9 patients had BILAG A/B mucocutaneous, 6/9 had BILAG A/B musculoskeletal and 4/9 had BILAG A/B renal. 6 months after obinutuzumab 1/9 patients had BILAG B mucocutaneous, no patients had BILAG A/B musculoskeletal and 2/9 patients had BILAG A/B renal. Median dsDNA reduced from 118 to 83 IU/mL, C3 increased from 0.53 to 1.02g/L and C4 increased from 0.095 to 0.23g/L. Prednisolone dose was reduced in 5/9 patients;before obinutuzumab all patients received 10mg or more. After obinutuzumab, 4/9 patients received 5mg and were in Lupus Low Disease Activity State (LLDAS). Patient 5 did not respond and required further methylprednisolone and cyclophosphamide at 4 months. Patient 6 had a partial renal response but required renal transplantation, which was successful. Patient 8 responded well to obinutuzumab but died from severe COVID-19 infection (unvaccinated). After obinutuzumab 6 patients with B-cell data all achieved complete depletion including 4/4 assessed with highly sensitive assays. Conclusion These results demonstrate obinutuzumab's efficacy in patients with secondary non-response to rituximab. These patients have severe disease with few treatment options, but previous responsiveness to Bcell depletion. Therefore, switching to another therapy in this class is mechanistically logical. Obinutuzumab appeared effective in renal and non-renal SLE as well as steroid-sparing. Immunological markers also improved. Obinutuzumab was generally well tolerated and will be further investigated for treatment-refractory lupus in the REGENCY and ALLEGORY trials.