CEA-Leti launches study on photodynamic therapy for cancer treatment

14 June 2010

CEA-Leti has launched the TARGET-PDT project designed to increase the effectiveness of photodynamic therapy (PDT) for treating cancer by developing a novel nano carrier-based approach.

PDT is a minimally invasive treatment that destroys cancer cells with a combination of a photoactive drug known as a photosensitizer and a specific wavelength of light. When the photosensitizers are activated by the laser light, they produce a form of oxygen that destroys illuminated cancer cells.

Focusing on using PDT against bone cancer and head-and-neck squamous cell carcinoma, which is a tumor eg of the oral cavity, the project will study the delivery and targeting of photosensitizers encapsulated into lipid nano-particles. For both cancer forms, current treatment regimes often result in low cure rates and show serious side effects or a poor functional outcome. The nano-carriers offer a high payload that will include antibodies targeting specific tumor biomarkers.

PDT has already shown significant potential for improving cancer treatment because it offers strictly focused application, biocompatibility with other forms of treatment, the option for repeated use, excellent cosmetic or functional outcomes and fast recovery. Indeed, typically there is a modest enhanced accumulation of the photosensitizer in tumor tissues and an additional selectivity is mainly provided by the confined illumination of the target area.

But, the use of PDT has been restrained by limited effectiveness of the photosensitizers on reaching the tumour and the potential damage to healthy cells near the tumour. Improved targeting of the photosensitizer and nano-particles is necessary to prevent damage to the surrounding healthy tissue.

CEA-Leti, which is coordinating this European project, expects the nano carrier-based approach will significantly improve delivery and targeting of the photosensitizer, enhancing concentrations at the tumor site even after systemic application.

The TARGET-PDT project will allow the partners to study all aspects of PDT treatment: nano-carrier size and payload, photosensitizers such as chlorines and phthalocyanines, targeting method and types of laser irradiation.

The experimental approach will be developed into a preclinical validation to deliver an optimised combination for first clinical “nano-PDT” at a later stage. By using nanotechnology-based photosensitizer delivery systems, the project will set the stage for improved control of the therapy and more comfort for cancer patients.