Combined photocoagulation and photodynamic therapy

Abstract

A method for treating a lesion of an animal, the animal having at least one vessel that carries blood to the lesion, comprising locating the vessel, administering a composition comprising a photodynamic agent, applying energy to the vessel to photocoagulate the vessel and thereby reduce the rate at which the treatment composition exits said lesion and applying energy to said lesion, of a type and an amount sufficient to excite the photodynamic agent, causing the lesion to undergo photodynamic therapy. Preferably, a dye that is both a fluorescent dye and a radiation absorbing dye, such as indocyanine green dye, is added to the treatment composition to allow (a) confirmation of the presence of the treatment composition b the lesion to be detected by fluorescent angiography and (b) the rate of blow flow to be reduced in the blood vessel feeding the lesion using dye enhanced photocoagulation.

Description

[0001]This application claims priority from U.S. patent application Ser. No. 60 / 396146, filed Jul. 17, 2002.[0002]This invention relates to a method for treating lesions, and more specifically where said lesion is an age related macular degeneration associated choroidal neovascularization, wherein said neovascularization is supplied by at least one blood vessel.BACKGROUND OF THE INVENTION[0003]Lesions are normally defined as an abnormal tissue structure located in an organ or other body part, and are often a manifestation of a harmful condition, disease or illness. Lesions may take many specific forms, such as choroidal neovascularizations (“CNVs”) which are found in the eye. In general, any abnormal vasculature in a body is a type of lesion.[0004]Lesions must often be identified and visualized prior to treatment and such methods are known in the art. For example, CNVs are routinely visualized using indocyanine green (“ICG”) dye angiography (“ICGA”). It is based on use of the near-i...

AI Technical Summary

Benefits of technology

This approach enhances the concentration of the photodynamic agent in the lesion, reduces treatment time and side effects, and decreases sunlight sensitivity, while maintaining effective treatment of the lesion with lower agent quantities.

Problems solved by technology

Photocoagulation of an entire CNV, however, involved the destruction of a significant portion of the retina.

When the agent is excited, it produces oxygen radicals which then attack the cells of the surrounding tissue, resulting in degradation of those cells.

Moreover, it now appears that the extent to which many PDT agents are selective for abnormal vasculature may not be as high as originally expected.

As a result, the non-target areas of the fundus may be subjected to more PDT-mediated damage than originally anticipated.

Large quantities of PDT agent also translate into an increase in the likelihood of side effects, higher total cost and more light sensitivity post-treatment.

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