Outcomes with chimeric antigen receptor T-cell therapy in Rheumatological disorders: A systematic review

Background: Chimeric antigen receptor T cell (CAR-T) therapy is an emerging form of immunotherapy that has recently gained recognition for treating hematological malignancies. This successful utilization of CAR-T therapy has attracted interest in its application in refractory rheumatological diseases. Here, we will review the use of CAR-T therapy in rheumatological diseases. Methods: Per PRISMA guidelines, a comprehensive literature search was performed on PubMed, Cochrane, and ClinicalTrials.gov using keywords for 'CAR-T cell therapy' and 'Rheumatological diseases' from inception to December 9, 2023. After screening 2977 articles, six studies reporting outcomes of CAR-T cell therapies in patients with underlying autoimmune /rheumatological diseases. Descriptive analysis was performed to represent demographics and clinical outcomes. Results: A total of 101 adult patients from six studies were included in this systematic review. The median age of the participants was 50.8 years (IQR: 14.875), with ages ranging from 18 to 83 years. The included studies comprised 2 case reports, 1 case series, one observational study, and two clinical trials. The studies were conducted globally, including USA, Germany, and China. The underlying rheumatologic conditions were systemic lupus erythematosus (17.8 %), rheumatoid arthritis (23.8 %), myasthenia gravis (13.8 %), neuromyelitis optica (11.9 %), and others (32.7 %). The target of CAR-T therapy included CD-19 in four studies and B cell maturation antigen (BCMA) in two studies. All the patients were on prior therapy, including glucocorticoids and diseasemodifying antirheumatic drugs. Follow-up ranged from a month to 1.5 years. Most of the studies reported improvement in the symptoms and decline in serological biomarkers of the underlying disease. The notable outcomes in the included studies were a 100 % response rate in five out of six studies. Grade 1 and 2 cytokine release syndrome (CRS) was observed in five studies. Only one study reported Grade 3 or higher CRS. 2 patients (1.98 %) developed neurotoxicity among the adverse effects. Conclusion: CAR-T cell therapy is a paradigm shift in managing rheumatologic diseases, with symptomatic improvement and biochemical control of these diseases. Although preliminary evidence indicates promising results, long-term follow-up and prospective clinical trials are needed to establish optimal timing and assess the safety and efficacy of CAR-T immunotherapy.