Comparing the anti-tumor effect of several bioreductive drugs when used in combination with photodynamic therapy (PDT).

Abstract

To compare the effect on the RIF-1 murine sarcoma of nine bioreductive agents from five different classes when used in combination with either photodynamic therapy or clamping. RIF-1 tumors implanted intradermally in C3H mice were treated with either 50J photodynamic therapy or with 120 min clamping in combination with either misonidazole, pimonidazole, metronidazole, nimorazole, RB6145, RSU1069, SR4233, mitomycin-C, or RB90740. The tumors were measured 3 times-per-week until reaching 4 x their initial treatment volume. RSU1069 produced the greatest anti-tumor activity in combination with both photodynamic therapy and clamping. RB6145 also substantially enhanced the effect of photodynamic therapy and clamping whereas misonidazole induced a smaller, but significant increase. Mitomycin-C had no effect under clamped conditions, but greatly increased the tumorcidal effect of photodynamic therapy. Mitomycin-C also induced an effect when given with light alone. None of the other agents showed any augmentation of the tumor cell killing induced by photodynamic therapy. Of the bioreductive agents studied RSU1069, RB6145 and mitomycin-C showed the greatest anti-tumor response in combination with photodynamic therapy.