Indeed, RO8994 showed to be as active as RG7388 and more than MI-888; the compound showed marked tumor growth inhibition of WTp53, MDM2-amplified SJSA-1 osteosarcoma tumor xenograft model, displaying significant tumor growth inhibition (>60%) at 1.56 mg kg−1, tumor stasis at 3.125 mg kg−1 and regression at 6.25 mg kg−1. This evidence concerns the gene MDM2 and neoplasm.