Person:

Prabhala, Rao

We have previously demonstrated that interleukin-17A (IL-17) producing Th17 cells are significantly elevated in blood and bone marrow (BM) in multiple myeloma (MM) and IL-17A promotes MM cell growth via the expression of IL-17 receptor. In this study, we evaluated anti-human IL-17A human monoclonal antibody (mAb), AIN457 in MM. We observe significant inhibition of MM cell growth by AIN457 both in the presence and absence of BM stromal cells (BMSC). While IL-17A induces IL-6 production, AIN457 significantly down-regulated IL-6 production and MM cell-adhesion in MM-BMSC co-culture. AIN-457 also significantly inhibited osteoclast cell–differentiation. More importantly, in the SCIDhu model of human myeloma administration of AIN-457 weekly for 4 weeks after the first detection of tumor in mice led to a significant inhibition of tumor growth and reduced bone damage compared to isotype control mice. To understand the mechanism of action of anti-IL-17A mAb, we report here, that MM cells express IL-17A. We also observed that IL-17A knock-down inhibited MM cell growth and their ability to induce IL-6 production in co-cultures with BMSC. These pre-clinical observations suggest efficacy of AIN 457 in myeloma and provide the rationale for its clinical evaluation for anti-myeloma effects and for improvement of bone disease.