Vision through photodynamic therapy of the eye

Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Heavy metal containing doai

Reexamination Certificate

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C514S912000

Reexamination Certificate

active

06548542

ABSTRACT:

TECHNICAL FIELD
The invention relates to a method to improve visual acuity by administering photodynamic therapy (PDT) to the eye.
BACKGROUND ART
Loss of visual acuity is a common problem associated with aging and with various conditions of the eye. Particularly troublesome is the development of unwanted neovascularization in the cornea, retina or choroid. Choroidal neovascularization leads to hemorrhage and fibrosis, with resultant visual loss in a number of recognized eye diseases, including macular degeneration, ocular histoplasmosis syndrome, myopia, and inflammatory diseases. Age-related macular degeneration (AMD) is the leading cause of new blindness in the elderly, and choroidal neovascularization is responsible for 80% of the severe visual loss in patients with this disease. Although the natural history of the disease is eventual quiescence and regression of the neovascularization process, this usually occurs at the cost of sub-retinal fibrosis and vision loss.
Current treatment of AMD relies on occlusion of the blood vessels using laser photocoagulation. However, such treatment requires thermal destruction of the neovascular tissue, and is accompanied by full-thickness retinal damage, as well as damage to medium and large choroidal vessels. Further, the sub-ject is left with an atrophic scar and visual scotoma. Moreover, recurrences are common, and visual prognosis is poor.
Developing strategies have sought more selective closure of the blood vessels to preserve the overlying neurosensory retina. One such strategy is photodynamic therapy, which relies on low intensity light exposure of photosensitized tissues to produce deleterious effects. Photoactive compounds are administered and allowed to reach a particular undesired tissue which is then irradiated with a light absorbed by the photoactive compound. This results in destruction or impairment of the surrounding tissue.
Photodynamic therapy of conditions in the eye has been attempted over the past several decades using various photoactive compounds, e.g., porphyrin derivatives, such as hematoporphyrin derivative and Photofrin porfimer sodium; “green porphyrins”, such as benzoporphyrin derivative (BPD), MA; and phthalocyanines. Schmidt, U. et al. described experiments using BPD coupled with low density lipoprotein (LDL) for the treatment of Greene melanoma (a nonpigmented tumor) implanted into rabbit eyes and achieved necrosis in this context (IOVS (1992) 33:1253 Abstract 2802). This abstract also describes the success of LDL-BPD in achieving thrombosis in a corneal neovascularization model. The corneal tissue is distinct from that of the retina and choroid.
Treatment of choroidal neovascularization using LDL-BPD or liposomal BPD has been reported in IOVS (1993) 34:1303: Schmidt-Erfurth, U. et al. (abstract 2956), Haimovici, R. et al. (abstract 2955); Walsh, A. W. et al. (abstract 2954). Lin, S. C. at al. (abstract 2953). An additional publication is Moulton, R. S. et al. (abstract 2294), IOVS (1993) 34:1169.
It has now been found that photodynamic treatment of eye conditions unexpectedly enhances the visual acuity of the subject.
DISCLOSURE OF THE INVENTION
The invention is directed to a method to improve visual acuity using photodynamic treatment methods. The methods are particularly effective when the photodynamic therapeutic protocol results in a diminution of unwanted neovasculature, especially neovasculature of the choroid.
Accordingly, in one aspect, the invention is directed to a method to enhance visual acuity which comprises administering to a subject in need of such treatment an amount of a formulation of a photoactive compound sufficient to permit an effective amount to localize in the eye of said subject; permitting sufficient time to elapse to allow an effective amount of said photoactive compound to localize in said eye; and irradiating the eye with light absorbed by the photoactive compound.


REFERENCES:
patent: WO 95/24930 (1995-09-01), None
Journal of Clinical Laser Medicine&Surgery,vol. 15, No. 1, p. 48 (1997): “QLT Photo Therapeutics Enters Phase III Trial for Age-Related Macular Degeneration”.
Schmidt-Erfurth, U. et al.,Investigative Ophthalmology&Visual Science,vol. 37, No. 3, p. 580 (1996): “Photodynamic Therapy of Subfoveal Choroidal Neovascularization Using Benzoporphyrin Derivative: First Results of a Multi-Center Trial”.
Bunse, A. et al.,Investigative Ophthalmology&Visual Science,vol. 37, No. 3, p. S223 (1996): “Photodynamic Therapy of Choroidal Neovascularization: Effects on Retinal Function Documented by Microperimetry”.
Miller, J.W. et al.,Archives of Ophthalmology, vol. 113, No. 6, pp. 810-818 (1995): “Photodynamic Therapy of Experimental Choroidal Neovascularization Using Lipoprotein-Delivered Benzoporphyrin”.
Young, L.H.Y. et al.,Archives of Ophthalmology,vol. 114, No. 2, pp. 186-192 (1996): “Photodynamic Therapy of Pigmented Choroidal Melanomas Using a Liposomal Preparation of Benzoporphyrin Derivative”.
Miller et al.,Chemical Abstracts,124:24930, 1995.
Schmidt-Erfurth, U. et al., “Photothrombosis of Ocular Neovascularization Using Benzoporphyrin Derivative (BPD),” Abstract No. 2956, IOVS (1993) 34:1303.
Haimovici,R. et al., “Localization of Benzoporphyrin Derivative Monoacid in the Rabbit Eye,” Abstract No. 2995, IOVS (1993) 34:1303.
Walsh, A.W. et al., “Photodynamic Therapy of Experimental Choroidal Neovascularization Using Benzoporphyrin Derivative Monoacid,” Abstract No. 2954, IOVS (1993) 34:1303.
Lin, S.C. et al., “Photodynamic Closure of Choroidal Vessels Using Benzoporphyrin Derivative,” Abstract No. 2953, IOVS (1993) 34:1303.
Moulton, R.S. et al., “Response of Retinal and Choroidal Vessels to Photodynamic Therapy Using Benzoporphyrin Derivative Monoacid,” Abstract No. 2294, IOVS (1993) 341:1169.
Schmidt, U. et al., “Photosensitizing Potency of Benzoporphyrin Derivative (BPD) Associated with Human Low Density Lipoprotein (LDL),” Abstract No. 2802, IOVS (1992) 33:1253.
Human Low Density Lipoprotein (LDL), Abstract No. 2802, IOVS (1992) 33:1253.

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