“…Etoposide has also been employed in numerous trials for refractory and relapsed neuroblastoma, with encouraging results [146] , while preclinical studies have examined other TOP1 and TOP2 inhibitors including namitecan, gimatecan and the investigational drugs EZN-2208, and (R +)XK469 [147] , [148] , [149] , [150] , [151] . Namitecan demonstrated antitumor activity in SK-N-AS neuroblastoma xenografts, inducing apoptosis and tumor shrinkage, and a significant enhancement of platinum agent activity [147] , whereas gimatecan produced significant regression of SK-N-DZ neuroblastoma xenografts in vivo [148] . This latter result supported the superior activity of gimatecan versus irinotecan and topotecan, in terms of producing growth arrest in 5 human neuroblastoma cell lines (SK-NDZ, BE(2)M17, LAN-1, RNGA, SK-N-BE(2)c) [149] .…”