XPO1 and plasma cell myeloma: KOS-2464 (Kosan Biosciences/Bristol-Myers Squibb), a semisynthetic NEI induces rapid and prolonged inhibition of CRM1, and apoptosis in drug resistant multiple myeloma cell lines at nanomolar concentrations (low IC50 value of 2 nM) without the toxicity associated with LMB (Turner et al., 2012b).