B cell depletion using bispecific T cell engagers (BiTEs) shows promise in the treatment of multidrug-resistant rheumatoid arthritis (RA), as indicated by a pilot study published in Nature Medicine. BiTEs are already an effective treatment for acute lymphoblastic leukaemia, and the latest findings highlight the potential of this approach for B cell-mediated autoimmune diseases, including RA.

In the latest study, six patients with multidrug-resistant active and severe RA were assigned to receive treatment with the CD19–CD3 BiTE blinatumomab, on a compassionate use basis. The patients had already failed to respond to treatment with various DMARDs: all six patients had previously been treated with methotrexate, leflunomide, TNF inhibitors and JAK inhibitors, and some of the patients had also received IL-6 inhibitors, abatacept and rituximab.