MDM2 and neoplasm: The same shortcomings are also found in RITA (reactivation of p53 and induction of tumor cell apoptosis), a small molecule inhibitor preventing the interaction between p53 and Mdm2 both in vitro and in vivo.383 Guided by the interactions among the p53 peptide, nutlin and Mdm2, a new class of inhibitors was developed and includes MI-219,384 SyI-155,385 MI-63,386 PRIMA1387 and RG7112 (Table 1).375 For example, MI-219 is an orally available compound with a subnanomolar affinity for Mdm2 and can increase the expression of p53 and p53-targeted genes.384