US 6,554,853 B2Granted

Use of pegylated photosensitizer conjugated with an antibody for treating abnormal tissue

AssigneeLight Sciences Corporation

InventorJames C. Chen

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Abstract

A photosensitizer suitable for use in administering photodynamic therapy (PDT), conjugated with antibodies that are targeted to antigens on abnormal tissue and polyethylene glycol (PEG) or other polymer that extends the residence time of the conjugate within a patient's body. The resulting pegylated targeted conjugate is administered to a patient, and after the antibodies have had sufficient time to bind with the antigens, light from an external or internal source having a waveband corresponding to an absorption waveband of the photosensitizer is administered. Use of an external light source that emits relatively long wavelength light enables the light to pass through any intervening dermal layer and normal tissue between the external light source and the treatment site. Since the photosensitizer in the conjugate is bound to the abnormal tissue, the light therapy has minimal effect on the intervening normal tissue. Furthermore, the efficacy of the PDT is enhanced due to the increased concentration of the photosensitizer of the conjugate linked to the abnormal tissue.

Claims4

Dependent claims

A method for improving a specificity and an extent with which a photosensitizer is taken up by abnormal tissue within a patient, compared to normal tissue, comprising the steps of:

(a) providing a microparticle that is characterized by being inert and biocompatible, a photosensitizer, an antibody that is targeted at antigens of the abnormal tissue, and a polymer;
(b) conjugating said antibody and said photosensitizer to said microparticle, forming a microparticle based antibody targeted photosensitizer conjugate that is adapted to link with the abnormal tissue;
(c) coating said microparticle based antibody targeted photosensitizer conjugate with a polymers forming a polymer coated microparticle based antibody targeted photosensitizer conjugate that is characterized by a prolonged in vivo residence time for the microparticle based antibody targeted photosensitizer conjugate in the patient;
and
(d) administering the polymer coated microparticle based antibody targeted photosensitizer conjugate to the patient, so that said antibody on the microparticle based antibody targeted photosensitizer conjugate links with the abnormal tissue, uptake of the polymer coated microparticle based antibody targeted photosensitizer conjugate by the abnormal tissue being substantially improved compared with a microparticle based antibody targeted photosensitizer conjugate that is not coated by the polymers and uptake of the polymer coated microparticle based antibody targeted photosensitizer conjugate by the normal tissue being substantially reduced compared with a microparticle based photosensitizer that is coated by the polymer.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/909,515Filed 20 Jul 2001 · division
Priority: 21 Dec 1998
Published: US 2001/0044623 A122 Nov 2001
Granted: 29 Apr 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

A61K 41/0057
Medicinal preparations obtained by treating materials with wave energy or particle radiation ; Therapies using these preparations: photodynamic…
A61K 47/60
Obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyureas or polyurethanes: the organic…
A61K 47/68
The non-active ingredient being a modifying agent: the modifying agent being an antibody, an immunoglobulin or a fragment thereof, e.g. an Fc-fragment
A61K 47/6927
The form being a particulate, a powder, an adsorbate, a bead or a sphere: the form being a solid microparticle having no hollow or gas-filled cores