Mice tolerate intraperitoneal dose of SMI-16a is 50 mg/kg daily for 5 days, while 100 mg/kg is overtly toxic. Treatment of the animals with SMI-16a for 5 days per week reduces the growth of tumors by approximately 50% and does not cause a loss of body weight. Subchronic dosing with SMI-16a does not affect the levels of red, white blood cells, including lymphocytes, monocytes, and granulocytes, indicating that the compound does not have myelosuppressive effects. SMI-16a does not have toxicity toward the liver as the albumin, alkaline phosphatase, and alanine aminotransferase levels are unchanged [1]. SMI-16a effectively prevents bone destruction while suppressing MM tumor growth in MM animal models[2].