Combination of photodynamic therapy + immunotherapy + chemotherapy in murine leukiemia.

Photodynamic therapy (PDT) is a treatment for cancer based on the photosensitization of tumor cells by photosensitive drugs and their subsequent destruction on exposure to light of particular wavelength. The combination of drug uptake in malignant tissues and selective delivery of laser-generated light provides an effective therapy with efficient tumor citotoxicity and minimal normal tissue damage. Since immune response of the host is important in the control of tumor growth and spreading, PDT is able to increase the antitumor immunity. In our laboratory we examined the antitumor effect of combination of PDT, with photoactivated M-THPC (meta-tetrahydroxyphenylchlorin, FOSCAN, Temoporphirin), adoptive immunotherapy, with immune lymphocytes, and chemotherapy on advanced murine tumors. Mice bearing L1210 tumor were treated at day +4 with Navelbine (NVB 1mg/Kg), at day +5,+6 with PDT (0.3mg/Kg of mTHPC and 100mW/cm(2) x 200'' of exposure of laser light), and at day + 7 with immune lymphocytes(IL), collected from mice pretreated with PDT(2x10(7) cells). The results show that the combination NVB + PDT + IL demonstrates a significant synergistic antitumor effect while the chemotherapy treatment with low dose of the drug is uneffective. The same positive results were obtained with the combination of Cisplatin (CDDP 0.5mg/Kg), PDT and IL, while the CDDP treatment alone is completely uneffective. In conclusion, these results suggest that it is possible to completely cure animals bearing advanced tumors, with a combined therapy, PDT + adoptive immunotherapy + low dose chemotherapy.