Objective:

To evaluate the safety and preliminary efficacy of CD19 CAR T cell therapy in patients with severe, treatment-refractory rheumatoid arthritis.

Approach:

• Study Design: A single-arm, open-label phase I clinical trial was conducted with six participants receiving mivocabtagene autoleucel after lymphodepleting chemotherapy.
• Participants: The study included three women and three men aged 31–69 with longstanding seropositive rheumatoid arthritis, previously treated with multiple therapies.
• Treatment Administration: Participants received a single infusion of 100 million CAR T cells, targeting CD19-positive B cells.

Key Findings:

• All six participants showed a reduction in disease activity scores, with a median reduction of 49% at week 24 and 34% at the latest follow-up.
• Three participants maintained remission without medication during follow-up of 36 to 52 weeks.
• Four participants achieved clinical remission; one relapsed after 31 weeks.
• Autoantibody levels decreased significantly, with a median decline of 94% in anti-mutated citrullinated vimentin antibodies.

Limitations:

• The study was small and open-label, limiting the ability to establish efficacy.
• Longer follow-up is needed to assess the impact on protective immunity.

Conclusion:

The study will advance to a randomized phase II trial comparing CD19 CAR T therapy with rituximab to evaluate response duration and depth.

Sources:

• Charité – Universitätsmedizin Berlin