Therapeutic liposome composition and method of preparation

Abstract

Reagents for use in preparing a therapeutic liposome composition sensitized to a target cell are described. The reagents include a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent and a plurality of targeting conjugates composed of a lipid, a hydrophilic polymer and a targeting ligand. The therapeutic, target-cell sensitized liposome composition is formed by incubating the liposomal composition with a selected conjugate.

1 - 32 . (Canceled)  
     
     
         33 . A method of formulating a therapeutic liposome composition having sensitivity to a target cell, comprising 
 providing a liposomal composition composed of pre-formed liposomes having an entrapped therapeutic agent;    providing a plurality of targeting conjugates a targeting conjugate composed of (i) a lipid having a polar head group and a hydrophobic tail, (ii) a hydrophilic polymer having a proximal end and a distal end, said polymer attached at its proximal end to the head group of the lipid, and (iii) a targeting ligand attached to the distal end of the polymer; and    combining the liposome formulation and the plurality of targeting conjugates to form said therapeutic, target-cell sensitive liposome composition.    
     
     
         34 . The method of  claim 33 , wherein said combining includes incubating under conditions effective to achieve insertion of said targeting conjugates into said pre-formed liposome.  
     
     
         35 . (Canceled)  
     
     
         36 . The method of  claim 33 , wherein said providing a plurality of targeting conjugates includes providing a plurality of targeting conjugates having a targeting ligand effective to bind cell surface receptors expressed on a target cell.  
     
     
         37 . The method of  claim 36 , wherein said providing a plurality of targeting conjugates includes providing a plurality of targeting conjugates having a targeting ligand with binding affinity for a cell receptor, where binding of said ligand with said cell receptor results in internalization of said liposomes.  
     
     
         38 . The method of  claim 33 , wherein the targeting ligand is an antibody or an antibody fragment.  
     
     
         39 . The method of  claim 38 , wherein the antibody or antibody fragment is a humanized murine antibody.  
     
     
         40 . The method of  claim 38 , wherein the targeting ligand specifically binds to an extracellular domain of a growth factor receptor.  
     
     
         41 . The method of  claim 40 , wherein the receptors are selected from the group consisting of c-erbB-2 protein product of the HER2/neu oncogene, epidermal growth factor receptor, basic fibroblast growth factor receptor, and vascular endothelial growth factor receptor.  
     
     
         42 . The method of  claim 38 , wherein the targeting ligand binds a receptor selected from the group consisting of E-selectin receptor, L-selectin receptor, P-selectin receptor, folate receptor, CD4 receptor, CD19 receptor,  αβ  integrin receptors and chemokine receptors.  
     
     
         43 . The method of  claim 33 , wherein the targeting ligand binds a receptor on a malignant B-cell or T-cell, said receptor selected from the group consisting of CD19, CD20, CD22, CD4, CD7 and CD8.  
     
     
         44 . The method of  claim 33 , wherein the targeting ligand is selected from the group consisting of folic acid, pyridoxal phosphate, vitamin B12, sialyl Lewis X , transferrin, epidermal growth factor, basic fibroblast growth factor, vascular endothelial growth factor, VCAM-1, ICAM-1, PECAM-1, RGD peptides and NGR peptides.  
     
     
         45 . The method of  claim 33 , wherein the hydrophilic polymer is selected from the group consisting of polyvinylpyrrolidone, polyvinylmethylether, polymethyloxazoline, polyethyloxazoline, polyhydroxypropyloxazoline, polyhydroxypropylmethacrylamide, polymethacrylamide, polydimethylacrylamide, polyhydroxypropylmethacrylate, polyhydroxyethylacrylate, hydroxymethylcellulose, hydroxyethylcellulose, polyethyleneglycol, polyaspartamide and hydrophilic peptide sequences.  
     
     
         46 . The method of  claim 33 , wherein the hydrophilic polymer is polyethylene glycol.  
     
     
         47 . The method of  claim 46 , wherein the polyethylene glycol has a molecular weight between 500-5,000 daltons.  
     
     
         48 . The method of  claim 33 , wherein the liposomes further contain a cationic lipid.  
     
     
         49 . The method of  claim 33 , wherein the entrapped therapeutic agent is a cytotoxic drug.  
     
     
         50 . The method of  claim 49  wherein the cytotoxic drug is an anthracycline antibiotic selected from the group consisting of doxorubicin, daunorubicin, epirubicin and idarubicin and analogs thereof.  
     
     
         51 . The method of  claim 49 , wherein the cytotoxic agent is a platinum compound selected from cisplatin, carboplatin, ormaplatin, oxaliplatin, zeniplatin, enloplatin, lobaplatin, spiroplatin, ((−)-(R)-2-aminomethylpyrrolidine (1,1-cyclobutane dicarboxylato)platinum), (SP-4-3(R)-1,1-cyclobutane-dicarboxylato(2-)-(2-methyl-1,4-butanediamine-N,N′)platinum), nedaplatin and (bis-acetato-ammine-dichloro-cyclohexylamine-platinum( IV)).  
     
     
         52 . The method of  claim 49 , wherein the cytotoxic agent is a topoisomerase 1 inhibitor selected from the group consisting of topotecan, irinotecan, (7-(4-methylpiperazino-methylene)-10,11-ethylenedioxy-20(S)-camptothecin), 7-(2-(N-isopropylamino)ethyl)-(20S)-camptothecin, 9-aminocamptothecin and 9-nitrocamptothecin.  
     
     
         53 . The method of  claim 49 , wherein the cytotoxic agent is a vinca alkaloid selected from the group consisting of vincristine, vinblastine, vinleurosine, vinrodisine, vinorelbine and vindesine.  
     
     
         54 . The method of  claim 33 , wherein the entrapped agent is a nucleic acid.  
     
     
         55 . The method of  claim 54 , wherein the nucleic acid is an antisense oligonucleotide or ribozyme.  
     
     
         56 . The method of  claim 54 , wherein the nucleic acid is a plasmid containing a therapeutic gene which when internalized by the target cells achieves expression of the therapeutic gene to produce a therapeutic gene product.  
     
     
         57 . The method of claim  32 , wherein said providing a liposomal composition comprises providing a liposomal composition composed of pre-formed liposomes having entrapped doxorubicin.  
     
     
         58 . The method of claim  32 , wherein said providing a plurality of targeting conjugates comprises providing a plurality of targeting conjugates comprised of a vesicle-forming lipid, polyethylene glycol, and a targeting ligand having binding affinity for a cell receptor.