Photodynamic treatment of targeted cells
AssigneeLight Sciences Corporation
InventorJames Chen
Life of this patent
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Abstract
The present invention is drawn to methods for photodynamic therapy (PDT) of a target cell, target tissue or target composition in a mammalian subject, using a therapeutically effective amount of a targeted substance, which is either a targeted photosensitizing agent, or a photosensitizing agent delivery system, or a targeted prodrug. This targeted substance preferably selectively binds to the target cell, target tissue or target composition. Light at a wavelength or waveband corresponding to that which is absorbed by the targeted substance is then administered. The light intensity is relatively low, but a high total fluence is employed to ensure the activation of the targeted photosensitizing agent or targeted prodrug product.
Claims17
A method for administering a photodynamic therapy to destroy or impair target cells expressing a VEGF receptor in a mammalian subject, comprising the steps of:
- (a) administering to the mammalian subject a therapeutically effective amount of a liposome delivery system, comprising:
- (i) a first conjugate comprising a first member of a ligand-receptor binding pair conjugated to one of an antibody and an antibody fragment that selectively binds to a VEGF receptor of the target cells;
- (ii) a second conjugate comprising a second member of the ligand-receptor binding pair, conjugated to a photoreactive compound;
- and
- (iii) a liposome, separately conjugated to the second member of the ligand-receptor binding pair, wherein:
- the first member binds to the second member of the ligand-receptor binding pair;
- (b) irradiating at least a portion of the mammalian subject in which the target cells are disposed, using light having a waveband corresponding at least in part to the characteristic light absorption waveband of the photoreactive compound;
- wherein
- the intensity of the light used for the step of irradiating and the duration of irradiation have been selected such that the target cells are destroyed and the non-target tissue through which the light passes remains undamaged.
A method for administering a photodynamic therapy to destroy or impair target cells in a tumor in a mammalian subject, comprising the steps of:
- (a) administering to the subject a therapeutically effective amount of a targeted photosensitizer compound having a characteristic light absorption waveband, wherein:
- the targeted photosensitizer compound selectively binds with the target cells;
- and
- the photosensitizer compound is targeted to a receptor on a vascular endothelial tissue or an abnormal vascular wall of a tumor;
- (b) activating the photosensitizer bound to the target cells by irradiating with light having a waveband corresponding at least in part to the characteristic light absorption waveband of the targeted photosensitizer compound from a light source disposed within the tumor, wherein:
- the intensity of the light used for the step of irradiating and the duration of irradiation are selected such that within a zone of treatment the target cells are destroyed and the non-target tissue through which the light passes remains undamaged;
- and
- (c) sequentially expanding the zone of treatment outward in a stepwise manner by repositioning the light source, thereby destroying tumor tissue.
A liposome delivery system, comprising:
- (i) a first conjugate comprising a first member of a ligand-receptor binding pair conjugated to one of an antibody and an antibody fragment that selectively binds to a VEGF receptor of the target cells;
- (ii) a second conjugate comprising a second member of the ligand-receptor binding pair, conjugated to a photoreactive compound;
- and
- (iii) a liposome, separately conjugated to the second member of the ligand-receptor binding pair, wherein the first member binds to the second member of the ligand-receptor binding pair.
Dependencies are inferred from the claim text.