Table 3.

Binding Affinity and Biodistribution Data for Radiolabeled αMSH Analogues Designed for Radionuclide Therapy of Melanoma.

Tracer Name	Average Binding Affinity (IC50, nmol/L)	Tumor Model	Time Point (hour p.i.)	Average Organ Uptake, %ID/g				Uptake Ratio			Reference
				Tumor	Blood	Muscle	Kidney	Tumor- To-Blood	Tumor- To-Muscle	Tumor- To-Kidney
188Re-(Arg11)CCMSH	1.9	B16F1	4	16.37	0.02	0.39	3.67	819	42	4.5	75
			24	3.50	0.13	0.13	0.37	27	27	9.5
	4.4	TXM13	4	2.02	0.04	0.27	6.24	51	7.5	0.3	76
			24	0.93	0.09	0.06	0.27	10	16	3.4
188Re-CCMSH	1.7	B16F1	4	9.78	0.25	0.04	6.57	39	245	1.5	75
			24	1.94	0.06	0.02	0.46	32	97	4.2
	3.2	TXM13	4	2.20	0.01	0.04	12.56	220	55	0.2	76
			24	0.87	0.04	0.02	0.39	22	44	2.2
177Lu-DOTA-Re(Arg11) CCMSH	N/A	B16F1	4	17.68	0.12	0.21	19.09	136	84	0.9	72
			24	9.05	0.12	0.04	13.75	91	226	0.7
177Lu-DOTA-GGNle- CycMSHhex	N/A	B16F1	4	15.78	0.15	0.05	9.68	105	316	1.6	74
			24	8.24	0.23	0.14	4.75	36	59	1.7
90Y-DOTA-Re(Arg11) CCMSH	N/A	B16F1	4	14.09	0.01	0.11	24.86	1,409	127	0.6	72
			24	4.28	0.03	0.30	9.69	146	14	0.4
86Y-DOTA-Re(Arg11) CCMSH	N/A	B16F1	4	9.98	0.04	0.04	16.92	259	228	N/A	62
			24	0.78	0.06	0.03	11.67	N/A	N/A	N/A
86Y-CHX-A”-Re(Arg11) CCMSH	3.8	B16F1	4	4.18	0.46	0.19	8.78	9.1	22	N/A	55
			24	2.79	0.06	0.05	7.13	N/A	N/A	N/A
212Pb-DOTA-Re(Arg11) CCMSH	N/A	B16F1	4	12.84	0.08	0.05	4.56	N/A	N/A	N/A	78
			24	4.59	0.02	0.00	2.93	N/A	N/A	N/A

Abbreviations: IC₅₀, half maximal inhibitory concentration; ID, injection dose; N/A, not applicable; p.i., post injection; αMSH denotes alpha-melanocyte-stimulating hormone.