Photodynamic Therapy for Cancer Patient
Development of Improved Second Generation Photosensitizer-Based Process of Photodynamic Therapy for Cancer Patient
Tech Area / Field
- MED-DRG/Drug Discovery/Medicine
3 Approved without Funding
VNIIEF, Russia, N. Novgorod reg., Sarov
- NIOPIK (Organic Intermediate Products and Dyes), Russia, Moscow\nMoscow Oncology Research Institute, Russia, Moscow
- CNRS / Center for Molecular Biophysics, France, Orleans
Project summaryThe objective of the project is to develop novel photosensitizers, a new set of equipment for photodynamic therapy and on their basis the improved process of therapy for cancer patients affordable for Russian regions.
Photodynamic therapy (PDT) is actively developing all over the world. Anti-tumor photodynamic effect is based on cytotoxic action of free radicals generated in tumor tissue during the contact of a tumor-localized photosensitizer molecule with light irradiation of certain wave length. The ability of an excited photosensitizer molecule to emit quanta of light makes it possible to control photosensitizer accumulation in tumor tissue and in a number of cases to mark the node.
There are several official preparations for PDT of cancer. A separate group is represented by PHOTOFRIN I and PHOTOFRIN II (USA), PHOTOSAN (Germany), and PHOTOHEM (Russia) which are similar porphyrin-based drugs.
PHOTOSENS has been developed in Russia on the basis of di-, tri-, and tetrasulphonated phtalocyanines of aluminum. It has been recently certified for clinical use.
Porphyrin-based photosensitizers are natural composite compounds. That is why they are difficult to reproduce and extremely expensive: $2,000 is the price of therapeutic dose for PHOTOFRIN and $300 – for PHOTOHEM). PHOTOHEM has no advantages over similar foreign preparations.
PHOTOSENS is a synthetic mixed preparation. Its production is easier than that of similar foreign products, while it is less expensive and more efficient in affecting tumors. But it has a significant disadvantage caused by skin phototoxicity resulting from slow elimination of the photosensitizer from the body.
PDT is efficiently used now for the therapy of small tumors accessible for irradiation: primary skin neoplasms, skin metastases of variously localized tumors, respiratory tract tumors (in bronchi and trachea), gastrointestinal tract tumors (in eosophagus, stomach, large and rectum intestine), urogenital tumors (in bladder, prostate, penis, vagina, cervix, vulva), and oropharingeal tumors (in tongue, oral cavity, nasopharynx, larynx).
PDT advantages identified in the course of clinical trials (the ability to use in patients with concomitant diseases, the absence of tissue trauma) made it possible to introduce this method in several Moscow hospitals. It was planned to supply special PDT rooms with sets of typical diagnostic and therapeutic equipment. But the price of such a room is more than $40,000 making it not easily affordable in Moscow and even less so Russian regions.
On the basis of successful experience in PHOTOSENS development, we plan to develop a novel improved photosensitizer and a set of equipment for PDT. Special attention will be given to decreasing the price of the irradiation source, photosensitizer and equipment for its detection in tissues. Efforts will be made to ensure the affordability of PDT for Russian regions.
Studies in the synthesis of xanthene, phenoxasin, and phentiasin dyes as well as new phthalocyanine and porphyrin compounds have started recently. Photophysical, physical, chemical, and biological properties of these compounds have been characterized.
In vitro studies have shown that some of the compounds demonstrate higher photoinduced cytotoxic activity than photosensitizers used in clinical practice. These compounds are less toxic. They are eliminated from the body more rapidly. Some of them absorb long wave length light (up to 770 nm). This property is quite important, as it gives the opportunity to use the irradiation with deeper penetration into tissues than it is possible with present photosensitizers, which will lead to damaging of tumor tissue more efficiently.
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