DTP3 is a D-tripeptide with a molecular weight of 525 Da, which retained all the main characteristics of the parental D-tetrapeptides in terms of bioactivity and specificity, including subnanomolar activity and high stability in vitro and potent and selective capacity to kill MM cells via apoptosis. DTP3 is a selective MKK7 binder, driving to a sustained JNK activation and consequent death of MM cell lines expressing GADD45β. DTP3 is about to enter clinical studies as a potential treatment for multiple myeloma.