Table 1.

Molecules used in preclinical and clinical trials as RET tyrosine kinase inhibitors.

Compound	Trade name	Structure	Targets	Clinical trials	Refs
PP1	Zaleplon	Pyrazolopyrimidine	RET	—	[50]
PP2
ZD6474	Vandetanib	Anilinoquinazoline	RET; VEGFR; EGFR	Phase II	[51]
RPI-1	—	Indolinone	RET; MET	—	[52]
SU5416	Sunitinib	Butanedioic acid	VEGFR-2; PDGFR; c-KIT; RET; CSF-1R	Phase II	[53, 54]
SU11248
ZD1839	Gefitinib	Anilinoquinazoline	EGFR	Phase II	[55, 56]
BAY43-9006	Sorafenib	Bis-aryl urea	RAF-1; BRAF; VEGFR-2/-3; PDGFR-B; Flt-3; c-KIT; RET	Phase II	[57, 58]
AMG706	Motesanib diphosphate	Diphosphate salt	VEGFR; PDGFR; KIT; RET	Phase II	[59, 60]
AG-013736	Axitinib	Benzamide	RET; VEGFR; PDGFR; c-KIT	Phase II	[61]
XL184/XL880			VEGFR2; RET and MET	Phase III	[***]

[***] Eder et al. [62]. LoRusso et al. [63]. Ross et al. [64]. Salgia et al. [65].