Vitamin-Receptor Binding Drug Delivery Conjugates

Abstract

The invention describes a vitamin receptor binding drug delivery conjugate, and preparations therefor. The drug delivery conjugate consists of a vitamin receptor binding moiety, a bivalent linker (L), and a drug. The vitamin receptor binding moiety includes vitamins, and vitamin receptor binding analogs and derivatives thereof, and the drug includes analogs and derivatives thereof. The vitamin receptor binding moiety is covalently linked to the bivalent linker, and the drug, or the analog or the derivative thereof, is covalently linked to the bivalent linker, wherein the bivalent linker (L) includes components such as spacer linkers, releasable linkers, and heteroatom linkers, and combinations thereof. Methods and pharmaceutical compositions for eliminating pathogenic cell populations using the drug delivery conjugate are also described.

1 .- 63 . (canceled) 
     
     
         64 . A ligand-linker-drug conjugate comprising:
 (a) an antibody;   (b) a bivalent linker; and   (c) a drug;   wherein the antibody is covalently linked to the bivalent linker;   the drug is covalently linked to the bivalent linker;   the bivalent linker comprises one or more components selected from the group consisting of spacer linkers, releasable linkers, and heteroatom linkers, and combinations thereof; and   at least one spacer linker is selected from the group consisting of   
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein n is an integer from 1 to 3 and each*represents a covalent bond to the rest of the conjugate; and 
         provided that the bivalent linker includes at least one releasable linker that is not a disulfide. 
       
     
     
         65 . The ligand-linker-drug conjugate of  claim 64 , wherein at least one heteroatom linker is a nitrogen, oxygen, or sulfur atom, or is selected from the group of formulae consisting of —NHR 1 NHR 2 —, —SO—, —S(O) 2 —, and —NR 3 O—, wherein R′, R 2 , and R 3  are each independently selected from the group consisting of hydrogen, alkyl, aryl, arylalkyl, substituted aryl, substituted arylalkyl, heteroaryl, substituted heteroaryl, and alkoxyalkyl. 
     
     
         66 . The ligand-linker-drug conjugate of  claim 65 , wherein at least one heteroatom linker is nitrogen, and wherein the substituent X 1  and the heteroatom linker are taken together with the spacer linker to which they are bound to form an heterocycle. 
     
     
         67 . The ligand-linker-drug conjugate of  claim 66 , wherein the heterocycle is selected from the group consisting of pyrrolidines, piperidines, oxazolidines, isoxazolidines, thiazolidines, isothiazolidines, pyrrolidinones, piperidinones, oxazolidinones, isoxazolidinones, thiazolidinones, isothiazolidinones, and succinimides. 
     
     
         68 . The ligand-linker-drug conjugate of  claim 64 , wherein the releasable linker is selected from the group consisting of methylene, 1-alkoxyalkylene, 1-alkoxycycloalkylene, 1-alkoxyalkylenecarbonyl, 1-alkoxycycloalkylenecarbonyl, carbonylarylcarbonyl, carbonyl(carboxyaryl)carbonyl, carbonyl(biscarboxyaryl)carbonyl, haloalkylenecarbonyl, alkylene(dialkylsilyl), alkylene(alkylarylsilyl), alkylene(diarylsilyl), (dialkylsilyl)aryl, (alkylarylsilyl)aryl, (diarylsilyl)aryl, oxycarbonyloxy, oxycarbonyloxyalkyl, sulfonylalkyl, iminoalkylidenyl, carbonylalkylideniminyl, iminocycloalkylidenyl, carbonylcycloalkylideniminyl, alkylenesulfonyl, alkylenethio, alkylenearylthio, and carbonylalkylthio, wherein each of said releasable linkers is optionally substituted with one or more substituents X 2 ;
 wherein each substituent X 2  is independently selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, halo, haloalkyl, sulfhydrylalkyl, alkylthioalkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroaryl, substituted heteroaryl, carboxy, carboxyalkyl, alkyl carboxylate, alkyl alkanoate, guanidinoalkyl, R 4 -carbonyl, R 5 -carbonylalkyl, R 6 -acylamino, and R 7 -acylaminoalkyl, wherein R 4  and R 5  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide, and wherein R 6  and R 7  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide.   
     
     
         69 . The ligand-linker-drug conjugate of  claim 64 , wherein the heteroatom linker is nitrogen, and wherein the releasable linker and the heteroatom linker are taken together to form a divalent radical comprising alkyleneaziridin-1-yl, alkylenecarbonylaziridin-1-yl, carbonylalkylaziridin-1-yl, alkylenesulfoxylaziridin-1-yl, sulfoxylalkylaziridin-1-yl, sulfonylalkylaziridin-1-yl, or alkylenesulfonylaziridin-1-yl, wherein each of said releasable linkers is optionally substituted with one or more substituents X 2 .
 wherein each substituent X 2  is independently selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, halo, haloalkyl, sulfhydrylalkyl, alkylthioalkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroaryl, substituted heteroaryl, carboxy, carboxyalkyl, alkyl carboxylate, alkyl alkanoate, guanidinoalkyl, R 4 -carbonyl, R 5 -carbonylalkyl, R 6 -acylamino, and R 7 -acylaminoalkyl, wherein R 4  and R 5  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide, and wherein R 6  and R 7  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide.   
     
     
         70 . The ligand-linker-drug conjugate of  claim 64 , wherein the drug is a mitomycin, a mitomycin derivative, or a mitomycin analog, and the releasable linker is selected from the group consisting of carbonylalkylthio, carbonyltetrahydro-2H-pyranyl, carbonyltetrahydrofuranyl, 1-(carbonyltetrahydro-2H-pyranyl)succinimid-3-yl, and 1-(carbonyltetrahydrofuranyl)succinimid-3-yl, wherein each of said releasable linkers is optionally substituted with one or more substituents X 2 ,
 wherein each substituent X 2  is independently selected from the group consisting of alkyl, alkoxy, alkoxyalkyl, hydroxy, hydroxyalkyl, amino, aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, halo, haloalkyl, sulfhydrylalkyl, alkylthioalkyl, aryl, substituted aryl, arylalkyl, substituted arylalkyl, heteroaryl, substituted heteroaryl, carboxy, carboxyalkyl, alkyl carboxylate, alkyl alkanoate, guanidinoalkyl, R 4 -carbonyl, R 5 -carbonylalkyl, R 6 -acylamino, and R 7 -acylaminoalkyl, wherein R 4  and R 5  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide, and wherein R 6  and R 7  are each independently selected from the group consisting of an amino acid, an amino acid derivative, and a peptide;   and wherein the aziridine of the mitomycin is bonded to the releasable linker to form an acylaziridine.   
     
     
         71 . The ligand-linker-drug conjugate of  claim 64 , wherein the antibody is a tomur-cell specific antibody or antibody fragment. 
     
     
         72 . The ligand-linker-drug conjugate of  claim 71 , wherein the antibody is a Fab or scFv fragment. 
     
     
         73 . The ligand-linker-drug conjugate of  claim 72 , wherein the antibody is a Fab fragment directed to EphA2. 
     
     
         74 . The ligand-linker-drug conjugate of  claim 64 , wherein the bivalent linker comprises an heteroatom linker, a spacer linker, and a releasable linker taken together to form 3-thiosuccinimid-1-ylalkyloxymethyloxy, where the methyl is optionally substituted with alkyl or substituted aryl. 
     
     
         75 . The ligand-linker-drug conjugate of  claim 64 , wherein the bivalent linker comprises a releasable linker, a spacer linker, and a releasable linker taken together to form dithioalkylcarbonylhydrazide, where the hydrazide forms an hydrazone with the drug, or analog or derivative thereof. 
     
     
         76 . The ligand-linker-drug conjugate of  claim 64 , wherein the bivalent linker comprises an heteroatom linker, a spacer linker, and a releasable linker taken together to form 3-thiosuccinimid-1-ylalkylcarbonylhydrazide, where the hydrazide forms an hydrazone with the drug, or analog or derivative thereof. 
     
     
         77 . The ligand-linker-drug conjugate of  claim 64 , wherein the bivalent linker comprises a plurality of spacer linkers selected from the group consisting of the naturally occurring amino acids and stereoisomers thereof. 
     
     
         78 . The ligand-linker-drug conjugate of  claim 64 , wherein the bivalent linker comprises a releasable linker, a spacer linker, and a releasable linker taken together to form 3-dithioalkyloxycarbonyl, where the carbonyl forms a carbonate with the drug, or analog or derivative thereof. 
     
     
         79 . A pharmaceutical composition comprising a ligand-linker-drug conjugate of  claim 64 , and at least one pharmaceutically acceptable carrier, diluent, or excipient. 
     
     
         80 . A method of eliminating a population of pathogenic cells in a host animal harboring the population of pathogenic cells wherein the members of the pathogenic cell population have an accessible binding site for an antibody, and wherein the binding site is uniquely expressed, overexpressed, or preferentially expressed by the pathogenic cells, said method comprising administering to said host a ligand-linker-drug conjugate of  claim 64 . 
     
     
         81 . The method of  claim 80 , wherein the accessible binding site is EphA2. 
     
     
         82 . The method of  claim 81 , wherein the antibody is a Fab fragment of an antibody directed to EphA2.