The proteasome inhibitior bortezomib depletes plasma cells and ameliorates clinical manifestations of refractory systemic lupus erythematosus.
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ABSTRACT: To investigate whether bortezomib, a proteasome inhibitor approved for treatment of multiple myeloma, induces clinically relevant plasma cell (PC) depletion in patients with active, refractory systemic lupus erythematosus (SLE).Twelve patients received a median of two (range 1-4) 21-day cycles of intravenous bortezomib (1.3?mg/m(2)) with the coadministration of dexamethasone (20?mg) for active SLE. Disease activity was assessed using the SLEDAI-2K score. Serum concentrations of anti-double-stranded DNA (anti-dsDNA) and vaccine-induced protective antibodies were monitored. Flow cytometry was performed to analyse peripheral blood B-cells, PCs and Siglec-1 expression on monocytes as surrogate marker for type-I interferon (IFN) activity.Upon proteasome inhibition, disease activity significantly declined and remained stable for 6?months on maintenance therapies. Nineteen treatment-emergent adverse events occurred and, although mostly mild to moderate, resulted in treatment discontinuation in seven patients. Serum antibody levels significantly declined, with greater reductions in anti-dsDNA (?60%) than vaccine-induced protective antibody titres (?30%). Bortezomib significantly reduced the numbers of peripheral blood and bone marrow PCs (?50%), but their numbers increased between cycles. Siglec-1 expression on monocytes significantly declined.These findings identify proteasome inhibitors as a putative therapeutic option for patients with refractory SLE by targeting PCs and type-I IFN activity, but our results must be confirmed in controlled trials.
SUBMITTER: Alexander T
PROVIDER: S-EPMC4484251 | biostudies-literature | 2015 Jul
REPOSITORIES: biostudies-literature
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