CD19 CAR T-Cell Therapy Shows Promise for Refractory Rheumatoid Arthritis

• Phase 1 data from the COMPARE trial show that CD19 CAR-T cell therapy was well tolerated in patients with severe, treatment-refractory rheumatoid arthritis, with all participants experiencing clinical improvement.
• Presenting findings at the 2026 Congress of EULAR – The European Alliance of Associations for Rheumatology on June 3, Fredrik Albach reported that mivocabtagene autoleucel yielded rapid CAR-T cell expansion and effective B-cell depletion in blood and tissues.
• Autoantibodies dropped by a median of more than 90%, and half of the participants achieved sustained remission without ongoing immunosuppressive therapy during follow-up periods ranging from 24 to 36 weeks.

Current therapies for rheumatoid arthritis rely on sustained immunosuppression rather than the restoration of immune tolerance, leaving off-drug remission rare in clinical practice. Recent anecdotal reports suggest that targeting CD19-expressing B cells can effectively reset aberrant humoral immunity. In an oral abstract presentation on June 3, 2026, at the congress of EULAR – The European Alliance of Associations for Rheumatology, Fredrik Albach presented phase 1 safety and efficacy results for mivocabtagene autoleucel, an autologous, fully human CD19-directed CAR-T cell therapy evaluated in six patients with anti-citrullinated protein antibody (ACPA)-positive, active rheumatoid arthritis that resisted standard interventions.

According to the data presented at the EULAR congress, the infusion was well tolerated. Cytokine release syndrome (CRS) events were limited to mild-to-moderate severity, and researchers observed no instances of immune effector cell-associated neurotoxicity syndrome (ICANS) or unexpected toxicities. The engineered CAR-T cells expanded rapidly, peaking within three weeks before declining gradually. This cellular kinetics profile coincided with deep depletion of B cells in both peripheral blood and tissue compartments.

Patients demonstrated marked reductions in autoantibody titers, achieving a median reduction greater than 90%. Sustained seroconversion to normal ACPA levels occurred in four of the six patients, while five achieved normal rheumatoid factor IgM (RF-IgM) levels. All six participants experienced measurable decreases in disease activity, highlighted by a median 49% reduction in the Disease Activity Score-28 using C-reactive protein (DAS28-CRP). American College of Rheumatology response criteria were met at ACR20 in five patients, ACR50 in four patients, and ACR70 in two patients. Half of the cohort achieved sustained clinical remission while off all ongoing immunosuppressive therapy.

B-cell repopulation following therapy did not trigger the reappearance of ACPA-positive memory B cells, a secondary rise in autoantibodies, or a rebound in disease activity. With the exception of one patient who experienced a moderate flare requiring the resumption of glucocorticoids, all participants remained off immunosuppressive therapy at the data cut-off, with a follow-up window spanning 24 to 36 weeks.

Broader investigative efforts presented concurrently at scientific meetings highlight the expanding scope of cellular immunotherapy across autoimmune conditions. Another group detailed the first multicentre experience utilizing a dual-target CD19/BCMA CAR-T approach in 11 patients suffering from refractory systemic sclerosis. Presenting these findings, Yajing Zhang from Beijing GoBroad Boren Hospital in China reported that dual-target CAR-T cell therapy induced rapid B-cell aplasia and significant improvements in skin thickness scores, with 73% of patients reaching low disease activity. Functional disability scores on the Health Assessment Questionnaire Disability Index (HAQ-DI) dropped from 1.0 to 0.2, and high-resolution computed tomography scans confirmed the regression of interstitial lung disease changes in 80% of baseline patients.

Furthermore, investigative teams are monitoring downstream immunological shifts. In a separate abstract presented by Yuichi Maeda and colleagues, researchers analyzed the gut microbiome and fecal immunoglobulin A in patients with severe systemic sclerosis, systemic lupus erythematosus, or idiopathic inflammatory myopathy treated with zorpocabtagene autoleucel. While gut microbial alpha-diversity remained reduced compared to healthy controls six months post-infusion, microbial overgrowths of Streptococcus species decreased.

Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.