How does the next generation of PDT differs from “traditional” PDT?
Although the next generation of PDT and PDT are both based on the principle of using light to kill pre-sensitized cancer cells, the next generation of PDT differs from PDT in several important ways. First, the sensitizing agent used in the next generation of PDT is in many cases more cancer-selective than the first Generation agents typically used in PDT. The agents licensed by the FDA for use in PDT are for the most part hematoporphyrins, derived from pig and ox blood. These blood-derived photosensitizers accumulate in all the tissues of the body, not just in the cancer tissue and are very slow to be metabolized and excreted. Patients who are given these agents must therefore be careful to avoid light for periods of weeks at a time or risk serious burns to the skin. By contrast, some advanced agents such as Photosoft are 95% metabolized and cleared from the body within 24 hours, freeing patients from the need to hide from the sun for weeks after treatment. Second, because the blood-de
