Based on preclinical studies [159,160] showing that BHQ880, a humanized IgG1 anti-DKK-1 mAb, inhibited myeloma cell-induced osteolytic lesion formation, as well as myeloma cell growth, led to a phase IB multi-center study of BHQ880 in combination with zoledronic acid and anti-myeloma therapy in 28 RRMM patients (NCT00741377). Here, DKK1 is linked to plasma cell myeloma.