Selective inhibitor of multidrug resistance-associated protein 1 (MRP1) and P-glycoprotein (P-gp). Increases the sensitivity of MRP1-overexpressing tumor cells (MCF7/VP) to doxorubicin , vincristine and etoposide by 3.8-, 14.6- and 11.6-fold respectively. Increases the efficacy of vincristine and etoposide in murine models of neuroblastoma in vivo . Displays at activity on MRP2, MRP3, MRP5 and MRP5 transporters.