In a small preliminary study, bortezomib treatment quickly resulted in clinical improvements in patients with severe forms of anti-NMDA receptor encephalitis, researchers have shown for the first time.
Anti-NMDA receptor encephalitis is a serious autoimmune disease. It is characterized by an inflammation of the brain, which can result in neurological and psychiatric symptoms, including psychoses, epileptic seizures and movement disorders.
Standard treatments currently available are often either inadequate or ineffective in patients with severe forms of the disease. This treatment resistance may be caused by certain anti-NMDA receptor antibody-producing plasma cells that remain inaccessible to current immunotherapies.
Proteasome Inhibitor Bortezomib
In a study led by Dr. Franziska Scheibe and Prof. Dr. Andreas Meisel from the Department of Neurology and the NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin researchers recorded outcomes obtained using a new treatment regimen. In addition to standard treatment, patients received bortezomib, a drug known as proteasome inhibitor that has proven successful in treating patients with plasmacytoma, a specific type of blood cancer.
Proteasomes play an important role in the degradation of proteins that regulate the cell cycle, thereby regulating cell growth.
Given their high rates of protein synthesis, antibody-producing plasma cells display particularly high levels of metabolic activity. This renders them as sensitive to the effects of the drug as cancer cells, and results in their death.
Eliminating Plasma Cells
In their study of five patients, the researchers were able to show for the first time that bortezomib treatment quickly resulted in clinical improvements in patients with severe forms of the disease. Treatment was also associated with a decline in the antibodies responsible for the disease.
“Bortezomib is capable of treating the causes of the disease by eliminating plasma cells. This makes it a valuable new treatment option in cases of anti-NMDA receptor encephalitis that have so far proven resistant to treatment,"
explains Dr Scheibe, the study’s first author.
Future studies will focus on developing biomarkers capable of making early predictions on whether patients will develop a severe form of the disease. This should then allow physicians to initiate specific treatments early.
“As is the case with all other treatments currently used in patients with this disease, our results need to be confirmed by randomized trials” notes Prof. Andreas Meisel.
Franziska Scheibe, Harald Prüss, Annerose M. Mengel, Siegfried Kohler, Astrid Nümann, Martin Köhnlein, Klemens Ruprecht, Tobias Alexander, Falk Hiepe, Andreas Meisel Bortezomib for treatment of therapy-refractory anti-NMDA receptor encephalitis Neurology, 2016; 10.1212/WNL.0000000000003536 DOI: 10.1212/WNL.0000000000003536