cep-33779 and Lupus-Nephritis

Systemic lupus erythematosus is a systemic autoimmune disease characterized by the presence of myriad autoantibodies, some with pathogenic potential, and diverse clinical manifestations. Involvement of the kidney is a major cause of morbidity and mortality in human lupus patients and in murine models of the disease. It is hoped that more specific inhibition of crucial disease pathways would improve patient response rates, while reducing the considerable rates of drug-related side effects associated with current therapy. IL-6 has a pivotal regulatory role in the development and maturation of long-lived plasma cells, one of the key cell types driving the lupus disease phenotype as the source for the majority of lupus-related autoreactive antibodies. In this study, Lu et al. target the IL-6 signal transduction pathway using a specific JAK2 inhibitor of the JAK-STAT pathway, CEP-33779. In murine lupus models, they show significant improvement in nephritis, and prolonged survival, in mice treated with CEP-33779. The study presents the promise of a novel pathway for therapeutic intervention in systemic lupus erythematosus using a medication administered orally.

Topics: Animals; Disease Models, Animal; Humans; Interleukin-6; Janus Kinase 2; Kidney; Lupus Erythematosus, Systemic; Lupus Nephritis; Mice; Plasma Cells; Pyridines; Signal Transduction; Treatment Outcome; Triazoles

Accumulating evidence suggests that autoreactive plasma cells play an important role in systemic lupus erythematosus (SLE). In addition, several proinflammatory cytokines promote autoreactive B cell maturation and autoantibody production. Hence, therapeutic targeting of such cytokine pathways using a selective JAK2 inhibitor, CEP-33779 (JAK2 enzyme IC(50) = 1.3 nM; JAK3 enzyme IC(50)/JAK2 enzyme IC(50) = 65-fold), was tested in two mouse models of SLE. Age-matched, MRL/lpr or BWF1 mice with established SLE or lupus nephritis, respectively, were treated orally with CEP-33779 at 30 mg/kg (MRL/lpr), 55 mg/kg or 100 mg/kg (MRL/lpr and BWF1). Studies included reference standard, dexamethasone (1.5 mg/kg; MRL/lpr), and cyclophosphamide (50 mg/kg; MRL/lpr and BWF1). Treatment with CEP-33779 extended survival and reduced splenomegaly/lymphomegaly. Several serum cytokines were significantly decreased upon treatment including IL-12, IL-17A, IFN-α, IL-1β, and TNF-α. Anti-nuclear Abs and frequencies of autoantigen-specific, Ab-secreting cells declined upon CEP-33779 treatment. Increased serum complement levels were associated with reduced renal JAK2 activity, histopathology, and spleen CD138(+) plasma cells. The selective JAK2 inhibitor CEP-33779 was able to mitigate several immune parameters associated with SLE advancement, including the protection and treatment of mice with lupus nephritis. These data support the possibility of using potent, orally active, small-molecule inhibitors of JAK2 to treat the debilitative disease SLE.

Topics: Administration, Oral; Animals; Antibodies, Antinuclear; Autoimmunity; Cell Separation; Cytokines; Disease Models, Animal; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Janus Kinase 2; Lupus Nephritis; Mice; Mice, Inbred MRL lpr; Plasma Cells; Pyridines; Triazoles