Trial to Evaluate Efficacy and Safety of Bortezomib in Patients With Severe Autoimmune Encephalitis (Generate-Boost)

A Multicenter Randomized, Controlled, Double-blinded Trial to Evaluate Efficacy and Safety of Bortezomib in Patients With Severe Autoimmune Encephalitis

Autoimmune Encephalitis is a disorder of the central nervous system caused by bodily substances, called antibodies. Antibodies normally help the body to prevent infections. However, in this disorder, the antibodies turn against the body itself and especially against cells in the brain and disturb the normal brain function. They are therefore called autoantibodies. There is no specific therapy for patients with autoimmune encephalitis so far. At the moment, the symptoms are treated with approved medications such as cortisone and immunotherapies also used in oncology. These therapies are unspecified and aim to reduce the number of autoantibodies and to contain the autoimmune process. In this trial we aim to test a new therapy option: in this therapy the body cells producing autoantibodies will be specifically targeted by a substance called bortezomib. The trial addresses patients with severe autoimmune encephalitis. The aim of the trial is to evaluate the efficacy and safety of bortezomib in patients with severe autoimmune encephalitis.

Autoimmune encephalitis is characterized by autoantibodies against neuronal surface antigens like the NMDA (N-methyl-D-aspartate) receptor or LGI1 (Leucin-rich glioma inactivated protein 1). So far, no specific therapy exists for this disease. Actual treatment includes combination therapies aiming for a reduction of pathogenic antibodies and containing the autoimmune process. In first line, patients are treated with plasmapheresis and cortisone. In second line, Rituximab and/or cyclophosphamide are administered. The response to these treatments are, however, often delayed and insufficient. Therefore, we need a specific therapy aiming at the antibody-producing plasma cells. Bortezomib is a proteasome inhibitor which interferes with NF-kB (nuclear factor kB) and the ubiquitin proteasome signaling pathway. Bortezomib acts preferably on cells with high protein synthesis - like plasma cells - and induces cell death in these cells. Bortezomib is used since more than a decade in chemotherapy of the multiple myeloma. Additionally, it is reported for systemic autoimmune diseases like lupus erythematodes that bortezomib leads to a depletion of plasma cells and therefore reduces the number of pathogenic antibodies and improves clinical outcome. The therapeutic potential of bortezomib for NMDAR encephalitis is described in a first case series with 5 patients.

1:1 randomization will be done centrally and stratified by site. Block randomization of variable block sizes will be used.

1 to 3 cycles Bortezomib with 1,3mg/m2 body surface s.c. + 20mg dexamethasone p.o. on days 1, 4, 8 and 11 (= 1 cycle)

1 to 3 cycles placebo (NaCl solution) s.c. + 20mg dexamethasone p.o. on days 1, 4, 8 and 11 (= 1 cycle)

1 to 3 cycles Bortezomib with 1,3mg/m2 body surface s.c. + 20mg dexamethasone p.o. on days 1, 4, 8 and 11 (= 1 cycle)

1 to 3 cycles placebo (NaCl solution) s.c. + 20mg dexamethasone p.o. on days 1, 4, 8 and 11 (= 1 cycle)

3, 6, 9 and 13 weeks after first administration of the study drug; GCS Score also 17 weeks after first administration of the study drug

Number of days in hospital or on ICU for each patient from first administration of the study drug until 17 weeks after first administration of the study drug

total score of the Rey Auditory Verbal Learning Test (RAVLT) (memory performance assessed by 3 word lists which are read to the patient and should be recalled and repeated by the patient; different proceeding for the 3 word lists)

total score of the Neuropsychiatric Inventory Questionnaire (NPI) (0 = best score to max 36 (patient) or 60 (caregiver)

GCS from 3 to 15 points (sum of 3 subscores eye response (1 to 4 points), motor response (1 to 6 points), verbal response (1 to 5 points); highest score = best score; 1= worst score)

Inclusion Criteria: Clinically diagnosed severe autoimmune encephalitis (defined as mRS ≥ 3) with autoantibodies to neuronal surface proteins in cerebrospinal fluid and / or serum Pretreatment with rituximab Age ≥18 years signed informed consent Women of childbearing potential (up to 2 years after menopause): negative pregnancy test Exclusion Criteria: pregnancy/breast-feeding acute infiltrative pulmonary and pericardial disease malignant tumor under current chemotherapy Simultaneous participation in another intervention study Previous participation in this study Known hypersensitivity to an ingredient of the investigational product Continued therapy with glucocorticoids / rituximab during the study duration (last dose must be administered before the first dose of the investigational product)

Wickel J, Chung HY, Platzer S, Lehmann T, Pruss H, Leypoldt F, Gunther A, Scherag A, Geis C; GENERATE Study Group. Generate-Boost: study protocol for a prospective, multicenter, randomized controlled, double-blinded phase II trial to evaluate efficacy and safety of bortezomib in patients with severe autoimmune encephalitis. Trials. 2020 Jul 8;21(1):625. doi: 10.1186/s13063-020-04516-7.