Effects on the B16 Sub-Cutaneous Melanoma

B16 sub-cutaneous melanoma is a slow-growing tumor when compared to the L1210 and P388 leukemias. This is a very tedious tumor on which very few drugs were found to be significantly active, (i.e., % ILS 40%). 

From Table 4, (III) is the only cyclophosphazene giving ILS approaching or exceeding the y level, either using a D -t- 1 monoinjection (1.40) protocol of treatment or within a Q3D (1, 4, 7, 10, 13) (5.20) schedule. Furthermore, the quantity of the first inoculation (i.e., 40 mg/kg on the day D + 1) seems to be determinant, the ILS value (53%) being larger than that (39%) obtained with the Q3D schedule. 

For some of these treatment schedules (Table 5) both the number of tumorbearing mice and the tumor diameters on the 12 and on the 14 day were recorded when compared to the control, the number and the size of tumors for the treated mice were considerably smaller, indicating the drugs were genuinely effective against s.c. B16 melanoma. Moreover, these two parameters are in good accord with the ILS determinations. 

Compound and schedule Number of tumor-bearing mice Size of tumors (cm) ) Number of tumor-bearing mice Size of tumors (cm) ) %ILS 

In conclusion of these antitumor tests on murine L1210, P388 and B16 tumors, it might be pointed out that the most effective in each case was the hexaziridino-cyclotriphosphazene NgPjAzg whereas NjPjClg and N P Clg appear to be poorly active, at least under our experimental conditions. Such a result requires some comments in the light of the ideas developed above. 

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