- Oh, Sangwook;
- Mao, Xuming;
- Manfredo-Vieira, Silvio;
- Lee, Jinmin;
- Patel, Darshil;
- Choi, Eun;
- Alvarado, Andrea;
- Cottman-Thomas, Ebony;
- Maseda, Damian;
- Tsao, Patricia;
- Ellebrecht, Christoph;
- Khella, Sami;
- OConnor, Kevin;
- Herzberg, Uri;
- Binder, Gwendolyn;
- Milone, Michael;
- Basu, Samik;
- Payne, Aimee;
- Richman, David
Muscle-specific tyrosine kinase myasthenia gravis (MuSK MG) is an autoimmune disease that causes life-threatening muscle weakness due to anti-MuSK autoantibodies that disrupt neuromuscular junction signaling. To avoid chronic immunosuppression from current therapies, we engineered T cells to express a MuSK chimeric autoantibody receptor with CD137-CD3ζ signaling domains (MuSK-CAART) for precision targeting of B cells expressing anti-MuSK autoantibodies. MuSK-CAART demonstrated similar efficacy as anti-CD19 chimeric antigen receptor T cells for depletion of anti-MuSK B cells and retained cytolytic activity in the presence of soluble anti-MuSK antibodies. In an experimental autoimmune MG mouse model, MuSK-CAART reduced anti-MuSK IgG without decreasing B cells or total IgG levels, reflecting MuSK-specific B cell depletion. Specific off-target interactions of MuSK-CAART were not identified in vivo, in primary human cell screens or by high-throughput human membrane proteome array. These data contributed to an investigational new drug application and phase 1 clinical study design for MuSK-CAART for the treatment of MuSK autoantibody-positive MG.