Methods and Compositions for Treating Conditions of the Eye

Abstract

Provided are methods and compositions for the photodynamic therapy (PDT) of ocular conditions characterized by the presence of unwanted choroidal neovasculature, for example, neovascular age-related macular degeneration. The selectivity and sensitivity of the PDT method can be enhanced by combining the PDT with an anti-angiogenesis factor, for example, angiostatin or endostatin, or with an apoptosis-modulating factor. Furthermore, the selectivity and sensitivity of the PDT may be further enhanced by coupling a targeting moiety to the photosensitizer so as to target the photosensitizer to choroidal neovasculature.

Description

REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Application Ser. No. 60 / 181,641, filed Feb. 10, 2000, the disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION[0002]The invention relates generally to photodynamic therapy-based methods and compositions for treating ocular conditions and, more specifically, the invention relates to photodynamic therapy-based methods and compositions for treating ocular conditions characterized by unwanted choroidal neovasculature.BACKGROUND[0003]Choroidal neovascularization can lead to hemorrhage and fibrosis, with resulting visual loss in a number of conditions of the eye, including, for example, age-related macular degeneration, ocular histoplasmosis syndrome, pathologic myopia, angioid streaks, idiopathic disorders, choroiditis, choroidal rupture, overlying choroid nevi, and certain inflammatory diseases. One of the disorders, namely, age-related macular degeneration (AMD), is the...

AI Technical Summary

Benefits of technology

[0010]The present invention is directed to PDT-based methods and compositions for treating ocular conditions associated with unwanted choroidal neovasculature. Such conditions include, for example, neovascular AMD, ocular histoplasmosis syndrome, pathologic myopia, angioid streaks, idiopathic disorders, choroiditis, choroidal rupture, overlying choroid nevi, and certain inflammatory diseases. The invention provides a more effective PDT-based method for treating unwanted CNV that has one or more of the following advantages: increased efficacy of treatment; increased selectivity for CNV; and reduced or delayed recurrence of the condition following PDT.

[0011]In one aspect, the invention provides a method of treating unwanted CNV in a mammal, wherein the CNV comprises endothelial cells, for example, capillary endothelial cells. The method comprises the steps of: (a) administering to the mammal, for example, a primate, preferably, a human, an anti-angiogenesis factor in an amount sufficient to permit an effective amount to localize in the CNV; (b) administering to the mammal an amount of a photosensitizer (PDT dye) sufficient to permit an effective amount to localize in the CNV; and (c) irradiating the CNV with laser light such that the light is absorbed by the photosensitizer so as to occlude the CNV. During practice of this method, the damage to endothelial cells disposed within the choroidal neovasculature is greater than the damage experienced by endothelial cells in a similar treatment lacking administration of the anti-angiogenesis factor. Furthermore, the anti-angiogenesis factor can potentiate the cytotoxicity of PDT. For example, the anti-angiogenesis factor and the PDT may act synergistically to selectively kill capillary endothelial cells, while at the same time sparing retinal cells, for example, retinal pigment epithelial cells and cells disposed in the neurosensory retina, for example, photoreceptor cells and Mueller cells.

[0012]The anti-angiogenesis factor can enhance the selectivity of the PDT by, for example, occluding the CNV while at the same sparing surrounding blood vessels, for example, normal choroidal and retinal vasculature, and / or tissue, for example, the overlying neurosensory retina. Accordingly, inclusion of the anti-angiogenesis factor makes the PDT method more selective for capillary endothelial cells. Furthermore, practice of the invention can slow down or delay the recurrence of choroidal neovasculature.

[0015]In another aspect, the invention provides a method of treating unwanted CNV in a mammal. The method comprises the steps of: (a) administering to a mammal, for example, a primate, preferably, a human, an amount of a photosensitizer to permit an effective amount to localize in the CNV, the photosensitizer comprising a targeting moiety that binds preferentially to cell surface ligands disposed on endothelial cells, for example, capillary endothelial cells, present in the CNV; and (b) irradiating the CNV with laser light such that the light is absorbed by the photosensitizer so as to occlude the CNV. The targeting moieties bind preferentially to CNV and, therefore, can increase the effective concentration of photosensitizer in the CNV relative to surrounding cells and tissues. Accordingly, such a method increases the selectivity of the PDT method for CNV while sparing surrounding retinal and large choroidal blood vessels and overlying neurosensory retina.

Problems solved by technology

Although clinicopathologic descriptions have been made, little is understood about the etiology and pathogenesis of the disease.

Currently there is no treatment for dry AMD.

Unfortunately, the majority of patients with neovascular AMD do not meet the criteria for laser photocoagulation therapy.

In addition, laser photocoagulation relies on thermal damage to the CNV tissue, which damages the overlying neurosensory retina with consequent loss of visual function.

Laser photocoagulation also is plagued by recurrences that occur in approximately 50% of cases.

Increasing photosensitizer or light doses do not appear to prevent this recurrence, and can even lead to undesired non-selective damage to retinal vessels (Miller et al.

The necessity for repeated PDT treatments can nevertheless be expected to lead to cumulative damage to the retinal pigment epithelium (RPE) and choriocapillaris, which may lead to progressive treatment-related vision loss.

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