Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D207/00—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom
  • C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
  • C07D207/44—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members
  • C07D207/444—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5
  • C07D207/448—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5 with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms, e.g. maleimide
  • C07D207/452—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having three double bonds between ring members or between ring members and non-ring members having two doubly-bound oxygen atoms directly attached in positions 2 and 5 with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms, e.g. maleimide with hydrocarbon radicals, substituted by hetero atoms, directly attached to the ring nitrogen atom
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/54—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being an organic compound
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
  • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
  • A61K47/68—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates 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
  • A61K47/6889—Conjugates wherein the antibody being the modifying agent and wherein the linker, binder or spacer confers particular properties to the conjugates, e.g. peptidic enzyme-labile linkers or acid-labile linkers, providing for an acid-labile immuno conjugate wherein the drug may be released from its antibody conjugated part in an acidic, e.g. tumoural or environment
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
  • A61P31/12—Antivirals
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C281/00—Derivatives of carbonic acid containing functional groups covered by groups C07C269/00 - C07C279/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group
  • C07C281/02—Compounds containing any of the groups, e.g. carbazates
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07H—SUGARS; DERIVATIVES THEREOF; NUCLEOSIDES; NUCLEOTIDES; NUCLEIC ACIDS
  • C07H15/00—Compounds containing hydrocarbon or substituted hydrocarbon radicals directly attached to hetero atoms of saccharide radicals
  • C07H15/20—Carbocyclic rings
  • C07H15/24—Condensed ring systems having three or more rings
  • C07H15/252—Naphthacene radicals, e.g. daunomycins, adriamycins

Definitions

• bifunctional compounds which link cytotoxic reagents to antibodies are known in the art. These compounds have been particularly useful in the formation of immunoconjugates directed against tumor associated antigens. Such immunoconjugates allow the selective delivery of toxic drugs to tumor cells.
• acylhydrazine compound 3-(2-pyridyl-dithio)propionyl hydrazide conjugated via an acylhydrazone bond to the 13-keto position of an anthracycline molecule
• Kaneko et al. (U.S. Serial No. 07/522,996, filed May 14, 1990, which is equivalent to European Patent
• the linkers contain a reactive pyridinyldithioor an ortho-nitrophenyldithio- group, by which the linker reacts with a suitable group attached to a cell reactive ligand, to form the completed conjugate.
• a reactive pyridinyldithioor an ortho-nitrophenyldithio- group by which the linker reacts with a suitable group attached to a cell reactive ligand, to form the completed conjugate.
• immunoglobulin achievable. It would be highly desirable to have immunoconjugates which provide a higher ratio of drug to targeting ligand.
• the present invention provides novel branched hydrazone linkers.
• the novel linkers are used to prepare novel drug/linker molecules and biologically active conjugates composed of a targeting ligand, a
• a therapeutically active drug and a branched linker capable of recognizing a selected target cell population (e.g., tumor cells) via the targeting ligand.
• drug/linker As used herein the term “drug/linker” or
• linker/drug molecule refers to the linker molecule coupled to two or more therapeutically active drug molecules
• conjuggate refers to the drug/linker molecule coupled to the targeting ligand.
• the linkers are branched so that more than one drug molecule per linker are coupled to the ligand.
• the number of drugs attached to each linker varies by a factor of 2 for each generation of branching.
• the number of drug molecules per molecule of linker can be 2, 4, 8, 16, 32, 64, etc.
• the factor of branching can be expressed mathematically as 2 n wherein n is a positive integer.
• a singly branched linker will have a first generation of branching or 2 1 , i.e., contains two drug molecules per linker.
• a doubly branched linker will have a second generation of branching or 2 2 , i.e., contains four drug molecules per linker.
• the present invention is directed to a branched linker for linking a thiol group derived from a targeting ligand to two or more drug moieties which comprises a compound having a terminus containing a thiol acceptor for binding to a thiol group (also called a sulfhydryl group) derived from a targeting ligand, at least one point of branching which is a polyvalent atom allowing for a level of branching of 2 n wherein n is a positive integer, and at least two other termini
• n 1, 2, 3, or 4; more preferably 1, 2 or 3; most preferably 1 or 2.
• the polyvalent atom is carbon or nitrogen, and the targeting ligand is an antibody or fragment thereof.
• the phrase "thiol group derived from the targeting ligand” means that the thiol group is already present on the targeting ligand or that the targeting ligand is chemically modified to contain a thiol group, which modification optionally includes a thiol spacer group between the targeting ligand and the thiol group.
• the phrase “an aldehyde or keto group derived from a drug moiety” means that the aldehyde or keto group is already present on the drug or the drug is chemically modified to contain an aldehyde or keto group.
• Also provided by the invention are intermediates for preparing the linkers, drug/linkers and/or conjugates; and a method for treating or preventing a selected disease state which comprises administering to a patient a conjugate of the invention.
• Figure 1 In vitro potency of BR96 straight chains hydrazone and branched hydrazone conjugates following various exposure times as described in Example 62.
• — ⁇ — represents BR96 MCDOXHZN and - - - ⁇ - - - represents BR96 MB-Glu-(DOX) 2 .
• FIGS. 2 In vitro potency of IgG straight chain hydrazone and branched hydrazone conjugates following various exposure times as described in Example 62.
• — ⁇ — represents IgG MCDOXHZN and — ⁇ — represents IgG MB-Glu-(DOX) 2 .
• the molecules are linked to the targeting ligand via the linker of the invention.
• the drug is attached to the linker through an acylhydrazone bond.
• the targeting ligand is attached to the linker through a thioether bond.
• the thioether bond is created by reaction of a sulfhydryl (thiol) group on the ligand, or on a short "thiol spacer" moiety attached to the ligand, with a thiol acceptor.
• the thiol acceptor can be a Michael Addition acceptor which becomes, after the reaction, a Michael Addition adduct.
• the targeting ligand is attached directly to the linker through a covalent thioether bond without a thiol spacer.
• A is a thiol acceptor
• Q is a bridging group
• b is an integer of 0 or 1;
• W is a spacer moiety
• n is an integer of 0 or 1;
• a is an integer of 2, 3 or 4;
• X is a moiety of the formula -NH-NH 2 or
• W, a, b and m are as defined
• X 1 is a moiety of the formula -NH-NH 2 or - or a moiety of the formula
• W, a, b, and m are defined hereinbefore, and X 2 is a moiety of the formula NH-NH 2 or
• W, a, b, and m are as defined hereinbefore, and
• X 3 is a moiety of the formula
• W, a, b and m are as defined hereinbefore, and X 4 is a moiety of the formula -NH-NH 2 or
• n is an integer of 1 to 6
• a is an integer of 0 or 1
• j is an integer of 2 to 6
• c is an integer of 0 or 1
• A is a thiol acceptor
• T is of the formula
• d is an integer of 2 to 6
• n 1 or 2
• f is an integer of 0 or 1
• b is an integer of 0 or 1
• g is an integer of 1 or 2
• X is a moiety of the formula -NH-NH 2 or
• Preferred branched linkers of formula II are where d is 2 , f is 0 , g is 1 , and/or b is 0 .
• Specific preferred compounds of formula II have the following formulae
• a is an integer of 0, 1, 2, or 3
• n is an integer of 1 to 6
• n is an integer of 0 or 1
• X 5 is an anthracycline antibiotic
• n is an integer of 1 to 6
• a is an integer of 0, 1, 2, or 3
• n is an integer of 0 or 1
• X 5 is an anthracycline antibiotic
• Preferred novel conjugates prepared from the drug/linker molecules of the invention have the formula
• A is a thiol adduct
• W is a spacer moiety
• n is an integer of 0 or 1
• a is an integer of 2, 3, or 4,
• b is an integer of 0 or 1
• p is an integer of 1 to 6
• Y is O or NH 2 + Cl-
• z is an integer of 0 or 1
• q is an integer of 1 to 10
• G is a targeting ligand
• W, a, and m are defined hereinbefore, and
• A is a thiol adduct
• n is an integer of 1 to 6
• a is an integer of 0 or 1
• j is an integer of 2 to 6
• c is an integer of 0 or 1
• p is an integer of 1 to 6
• Y is O or NH 2 + Cl-
• z is an integer of 0 or 1
• q is an integer of 1 to 10
• G is a targeting ligand
• T is of the formula
• d is an integer of 2 to 6
• m is an integer of 1 or 2
• f is an integer of 0 or 1
• b is an integer of 0 or 1
• g is an integer of 1 or 2
• anthracycline antibiotic and the ligand is an antibody.
• anthracycline is bound to the linker through an acylhydrazone bond at the 13-keto position of the anthracycline compound.
• the targeting ligand preferably an antibody or fragment thereof, then is bound, through the linker, to the anthracycline compound. In an especially preferred embodiment, this linkage occurs through a reduced
• disulfide group i.e. a free sulfhydryl or thiol group (-SH) on an antibody.
• anthracycline drug moiety is adriamycin, the thiol acceptor ia a
• Addition adduct is derived, especially a maleimido-group, and the antibody moiety is a chimeric or humanized antibody.
• compositions such as one comprising a pharmaceutically effective amount of a compound of Formula III or IV associated with a
• the present invention provides novel branched linker/drug molecules composed of a drug, and a
• thioether-containing linker having at least two drug molecules which can be joined to a ligand capable of targeting a selected cell population.
• the drugs are joined to the linker through an acylhydrazone bond.
• the point of branching is a polyvalent atom, preferably a carbon atom or nitrogen atom.
• the ligand is joined directly to the linker through a thioether bond. Normally, this bond will be created by reaction of a reactive sulfhydryl (-SH) group on the ligand, or on a spacer moiety (e.g., one derived from the SPDP or iminothiolane chemistry described below), with a thiol acceptor such as a Michael Addition acceptor.
• a reactive sulfhydryl (-SH) group on the ligand, or on a spacer moiety (e.g., one derived from the SPDP or iminothiolane chemistry described below), with a thiol acceptor such as
• the invention also provides methods for the
• the conjugates comprise at least two drug molecules connected by a linker of the invention to a targeting ligand molecule that is reactive with the desired target cell population.
• the targeting ligand molecule can be an immunoreactive protein such as an antibody, or fragment thereof, a non-immunoreactive protein or peptide ligand such as bombesin or, a binding ligand recognizing a cell associated receptor such as a lectin or steroid molecule.
• spacer refers to a bifunctional chemical moiety which is capable of
• the "W" spacer links a keto group to a nitrogen atom. Examples of spacer molecules are described in S.S. Wong, Chemistry of Protein Conjugation and Crosslinking, CRC Press,
• g is an integer of 1 to 6, preferably 2 to 4, more preferably 2.
• the most preferred spacer has the formula
• the bridging group is a bifunctional chemical moiety which is capable of covalenting linking together two spaced chemical moieties into a stable tripartate
• bridging group "Q" covalently links the thiol acceptor to a keto moiety.
• An example of a bridging group has the formula
• f is an integer of 0 to 10
• h is an integer of 0 to 10
• g is an integer of 0 or 1
• Z is S, O, NH, SO 2 , phenyl, naphthyl, a
• Preferred cycloaliphatic moieties include
• heteroaromatic moieties include pyridyl, furanyl, pyranyl, pyrimidinyl, pyrazinyl, pyridazinyl, oxazinyl, pyrrolyl, thiazolyl, morpholinyl, and the like.
• f + h is an integer of 2 to 6 preferably 2 to 4 and more preferably 2.
• f is 0 , 1 or 2
• h 0, 1 or 2.
• the thiol acceptor "A" is linked to the ligand via a sulfur atom derived from the ligand.
• the thiol acceptor becomes a thiol adduct after bonding to the ligand through a thiol group via a thioester bond.
• the thiol acceptor can be , for example, an alpha-substitited acetyl group.
• Y is a leaving group.
• leaving groups include Cl, Br, I, meaylate, tosylate, and the like.
• the thiol acceptor is an alpha-substituted acetyl group, the thiol adduct after linkage to the ligand forms the bond -S-CH 2 -
• the thiol acceptor is a Michael Addition acceptor.
• a representative Michael Addition acceptor of this invention has the formula
• Michael Addition acceptor After linkage to the ligand, the Michael Addition acceptor becomes a Michael Addition adduct, such as of the formula A
• the drug of the drug/linker molecule and conjugates of the present invention are effective for the usual purposes for which the corresponding drugs are effective, and have superior efficacy because of the ability, inherent in the ligand, to transport the drug to the desired cell where it is of particular benefit. Further, because the conjugates of the invention can be used for modifying a given biological response, the drug moiety is not to be construed as limited to classical chemical therapeutic agents.
• cytotoxic drugs particularly those which are used for cancer therapy.
• Such drugs include, in general, DNA damaging agents, anti-metabolites, natural products and their analogs.
• Preferred classes of cytotoxic agents include the anthracycline family of drugs.
• Particularly useful members of that class include, for example, daunorubicin, doxorubicin, carminomycin, morpholino doxorubicin, diacetylpentyl doxorubicin and their
• D is a drug moiety having pendant to the backbone thereof a chemically reactive functional group by means of which the drug backbone is bonded to the linker, said functional group selected from the group consisting of an aldehyde or a ketone.
• cytotoxic agents for use as drugs in the present invention include drugs of the following formula:
• R 1 is -CH 3 , -CH 2 OH, -CH 2 OCO ⁇ CH 2 ) 3 CH 3 or - CH 2 OCOCH(OC 2 H 5 ) 2
• R 2 is -OCH 3 , -OH or -H
• R 3 is -NH 2 , -NHCOCF 3 , 4-morpholinyl, 3-cyano-4- morpholinyl, 1-piperidinyl, 4-methoxy-1-piperidinyl, benzylamine, dibenzylamine, cyanomethylamine, 1-cyano-2- methoxyethyl amine, or NH-(CH 2 ) 4 -CH(OAc) 2 ;
• R 4 is -OH, -OTHP, or -H
• R 5 is -OH or -H provided that R 5 is not -OH when R 4 is -OH or -OTHP.
• Formula (V) includes compounds which are drugs, or are derivatives of drugs, which have acquired in the art different generic or trivial names.
• Table I which follows, represents a number of anthracycline drugs and their generic or trivial names and which are especially preferred for use in the present invention.
• Doxorubicin also be a highly preferred drug is Doxorubicin.
• Doxorubicin also be a highly preferred drug is Doxorubicin.
• Doxorubicin also be a highly preferred drug is Doxorubicin.
• DOX is that anthracycline shown on Table I in which R 1 is -CH 2 OH, R 3 is -OCH 3 , R 4 is -NH 2 ,
• R 5 is -OH, and R 6 is -H.
• the "ligand” includes within its scope any molecule that specifically binds or reactively associates or complexes with a receptor or other receptive moiety associated with a given target cell population.
• This cell reactive molecule, to which the drug reagent is linked via the linker in the conjugate, can be any molecule that binds to, complexes with or reacts with the cell population sought to be therapeutically or otherwise biologically modified and, which possesses a free
• the cell reactive molecule acts to deliver the therapeutically active drug moiety to the particular target cell population with which the ligand reacts.
• Such molecules include, but are not limited to, large molecular weight proteins such as, for example, antibodies, smaller molecular weight proteins, polypeptides or peptide ligands, and non-peptidyl ligands.
• the non-immunoreactive protein, polypeptide, or peptide ligands which can be used to form the conjugates of this invention may include, but are not limited to, transferrin, epidermal growth factors ("EGF"), bombesin, gastrin, gastrin-releasing peptide, platelet-derived growth factor, IL-2, IL-6, tumor growth factors ("TGF”), such as TGF-a and TGF-b, vaccinia growth factor (“VGF”), insulin and insulin-like growth factors I and II.
• Non-peptidyl ligands may include, for example, carbohydrates, lectins, and apoprotein from low density lipoprotein.
• the immunoreactive ligands comprise in antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as antigen-recognizing immunoglobulin (also referred to as
• immunoglobulin or an antigen-recognizing fragment thereof.
• immunoglobulins are those having the following properties of the amino acids
• immunoglobulins which can recognize a tumor-associated antigen.
• immunoglobulin may refer to any recognized class or subclass of immunoglobulins such as IgG, IgA, IgM, IgD, or IgE. Preferred are those
• immunoglobulins which fall within the IgG class of immunoglobulins.
• the immunoglobuin can be derived from any species. Preferably, however, the immunoglobulin is of human, murine, or rabbit origin. Furthermore, the immunoglobulin may be polyclonal or monoclonal,
• immunoglobulin fragments may include, for example, the Fab", F(ab') 2 , F v or Fab fragments, or other antigen recognizing immunoglobulin fragments.
• immunoglobulin fragments can be prepared, for example, by proteolytic enzyme digestion, for example, by pepsin or papain digestion, reductive alkylation, or recombinant techniques.
• proteolytic enzyme digestion for example, by pepsin or papain digestion, reductive alkylation, or recombinant techniques.
• the materials and methods for preparing such immunoglobulin fragments are well-known to those skilled in the art. See generally, Parham, J. Immunology, 131, 2895 (1983); Lamoyi et al., J. Iinmunological Methods, 56, 235 (1983); Parham, id. , 53, 133 (1982); and Matthew et al., id ., 50, 239 (1982).
• the immunoglobulin can be a "chimeric antibody" as that term is recognized in the art. Also the
• immunoglobulin may be a "bifunctional" or “hybrid” antibody, that is, an antibody which may have one arm having a specificity for one antigenic site, such as a tumor associated antigen while the other arm recognizes a different target, for example, a hapten which is, or to which is bound, an agent lethal to the antigen-bearing tumor cell.
• the bifunctional antibody may be one in which each arm has specificity for a different epitope of a tumor associated antigen of the cell to be therapeutically or biologically modified.
• the hybrid antibodies have a dual specificity, preferably with one or more binding sites specific for the hapten of choice or more or more binding sites specific for a target antigen, for example, an antigen associated with a tumor, an infectious organism, or other disease state.
• hybrid or bifunctional antibodies may be derived, as noted, either biologically, by cell fusion techniques, or chemically, especially with cross-linking agents or disulfide bridge-forming reagents, and may be comprised of whole antibodies and/or fragments thereof. Methods for obtaining such hybrid antibodies are disclosed, for example, in PCT Application WO83/03679, published
• bifunctional antibodies are those biologically prepared from a "polydoma” or "quadroma” or which are
• cross-linking agents such as bis- (maleimido) -methyl ether (“BMME”), or with other cross-linking agents familiar to those skilled in the art.
• BMME bis- (maleimido) -methyl ether
• the immunoglobulin may be a single chain antibody ("SCA”). These may consist of single chain Fv fragments (“scFv”) in which the variable light (“V L ”) and variable heavy (“VH”) domains are linked by a peptide bridge or by disulfide bonds. Also, the immunoglobulin may consist of single V H domains (dAbs) which possess antigen-binding activity. See, e.g., G. Winter and C. Milstein, Nature, 349, 295 (1991); R. Glockshuber et al.,
• chimeric monoclonal antibodies preferably those chimeric antibodies having specificity toward a tumor associated antigen.
• chimeric antibody refers to a monoclonal antibody comprising a variable region, i.e. , binding region, from one source or species and at least a portion of a
• chimeric antibodies comprising a murine variable region and a human constant region are especially preferred in certain applications of the invention, particularly human therapy, because such antibodies are readily prepared and may be less immunogenic than purely murine monoclonal antibodies.
• Such murine/human chimeric antibodies are the product of expressed immunoglobulin genes comprising DNA segments encoding murine immungobulin constant regions .
• Other forms of chimeric antibodies encompassed by the invention are those in which the class or subclass has been modified or changed from that of the original antibody. Such "chimeric" antibodies are also referred to as "class-switched antibodies”.
• chimeric antibody is the concept of "humanized antibody”, that is those antibodies in which the framework or “complementarity determining regions (“CDR") have been modified to comprise the CDR of an immunoglobulin of different specificitry as compared to that of the parent immunoglobulin.
• CDR complementarity determining regions
• a murine CDR is grafted into the framework region of a human antibody to prepare the "humanized antibody”. See, e.g., L. Riechmann et al., Nature 332, 323 (1988); M. S. Neuberger et al., Nature 314, 268 (1985).
• Particularly preferred CDR's correspond to those representing sequences recognizing the antigens noted above for the chimeric and bifunctional antibodies.
• the reader is referred to the teaching of EPA 0 239 400 (published September 30, 1987), incorporated herein by reference, for its teaching of CDR modified antibodies.
• bifunctional-chimeric antibody can be prepared which would have the benefits of lower immunogenicity of the chimeric or humanized antibody, as well as the
• bifunctional-chimeric antibodies can be synthesized, for instance, by chemical synthesis using cross-linking agents and/or recombinant methods of the type described above.
• the present invention should not be construed as limited in scope by any particular method of production of an antibody whether bifunctional, chimeric, bifunctional-chimeric, humanized, or an antigen-recognizing fragment or derivative thereof.
• the invention encompasses within its scope immunoglobulins (as defined above) or
• immunoglobulin fragments to which are fused active proteins for example, an enzyme of the type disclosed in
• antibody constructions also include, within their individual contexts constructions comprising antigen recognizing fragments. As one skilled in the art will recognize, such fragments could be prepared by traditional enzymatic cleavage of intact bifunctional, chimeric, humanized, or chimeric-bifunctional antibodies. If, however, intact antibodies are not susceptible to such cleavage, because of the nature of the construction involved, the noted
• constructions can be prepared with immunoglobulin fragments used as the starting materials; or, if recombinant techniques are used, the DNA sequences, themselves, can be tailored to encode the desired
• fragment which, when expressed, can be combined in vivo or in vitro, by chemical or biological means, to prepare the final desired intact immunoglobulin "fragment". It is in this context, therefore, that the term “fragment” is used.
• the immunoglobulin (antibody), or fragment thereof, used in the present invention may be polyclonal or monoclonal in nature.
• Monoclonal antibodies are the preferred immunoglobulins, however.
• the preparation of such polyclonal or telomeres are the preferred immunoglobulins, however.
• the preparation of such polyclonal or telomeres are the preferred immunoglobulins, however.
• hybridomas and which are useful in the practice of the present invention are publicly available from sources such as the American Type Culture Collection ("ATCC”) 12301 Parklawn Drive, Rockville, Maryland 20852 or, commercially, for example, from Boehringer-Mannheim
• monoclonal antibodies for use in the present invention are those which recognize tumor associated antigens.
• Such monoclonal antibodies are not to be so limited, however, and may include, for example, the following (the disclosures of which are incorporated herein by reference):
• the ligand containing conjugate is derived from chimeric antibody BR96,
• ChiBR96 is an internalizing murine/human chimeric antibody and is reactive, ad noted, with the fucosylated Lewis Y antigen expressed by human carcinoma cells such as those derived from breast, lung, colon, and ovarian carcinomas. Modified and/or humanized BR96 antibody can also be used in the present invention.
• immunoglobulin or “antibody” encompasses within its meaning all of the
• the conjugates of the invention demonstrate improved activity relative to linear conjugates.
• the present invention also encompasses pharmaceutical compositions, combinations and methods for treating diseases such as cancers and other tumors, non-cytocidal viral or other pathogenic infections, and auto-immune diseases. More particularly, the invention includes methods for treating disease in mammals wherein a pharmaceutically effective amount of at least one conjugate of the invention is administered in a pharmaceutically acceptable manner to the host mammal, preferably humans.
• an embodiment of this invention may involve the use of a number of conjugates wherein the specificity of the antibody component of the conjugate varies, i.e., a number of conjugates are used, each one having an antibody that binds specifically to a different antigen or to different sites or epitopes on the same antigen or to different sites or epitopes on the same antigen present on the cell population of interest.
• the drug component of these conjugates may be the same or may vary.
• this embodiment may be especially useful in the treatment of certain tumors where the amounts of the various antigens on the surface of a tumor is unknown or the tumor cell population is heterogeneous in antigen expression and one wants to be certain that a sufficient amount of drug is targeted to all of the tumor cells at the tumor site.
• this embodiment is important for achieving a high degree of specificity for the tumor because the likelihood that normal tissue will possess all of the same tumor-associated antigens is small (see, J.
• conjugates can be used, wherein only to drug component of the conjugate varies.
• a particular antibody can be linked to two or more doxorubicins to form one conjugate and can be linked to two or more daunomycins to form a second conjugate. Both conjugates can then be
• An additional embodiment includes the conjugation of more than one drug to a particular antibody to form a conjugate bearing a variety of different drugs along its surface - all linked to the antibody via acylhydrazone bonds. Administration of the conjugate of this embodiment results in the release of a number of different drugs at the site of or within the target cells.
• a combination of drug-targeting ligand conjugates can be used wherein the drug can be targeted to a cell population carrying a specific antigen as well as a receptor for a specific ligand on its surface. Again, one type of drug or number of different drugs can be used in this combination therapy.
• the conjugates of the invention can be administered in the form of pharmaceutical compositions using
• intralymphatic or administration directly into the site of a selected cell population such as a tumor.
• conjugates for in vivo treatment, it may be useful to use conjugates comprising antibody fragments such as Fab or F(ab") 2 or chimeric or humanized antibodies.
• compositions of the invention-comprising the conjugates - may be in a variety of dosage forms which include, but are not limited to, solid, semi-solid and liquid dosage forms such as tablets, pills, powders, liquid solutions or suspensions, suppositories, polymeric microcapsules or microvesicles, liposomes, and injectable or infusible solutions.
• dosage forms include, but are not limited to, solid, semi-solid and liquid dosage forms such as tablets, pills, powders, liquid solutions or suspensions, suppositories, polymeric microcapsules or microvesicles, liposomes, and injectable or infusible solutions.
• solid, semi-solid and liquid dosage forms such as tablets, pills, powders, liquid solutions or suspensions, suppositories, polymeric microcapsules or microvesicles, liposomes, and injectable or infusible solutions.
• the preferred form depends upon the mode of administration and the
• the pharmaceutical compositions may also include conventional pharmaceutically carriers known in the art such as serum proteins such as human serum albumin, buffer substances such as phosphates, water or salts or electrolytes.
• serum proteins such as human serum albumin
• buffer substances such as phosphates, water or salts or electrolytes.
• the most effective mode of administration and dosage regimen for the conjugates of this invention depends upon the severity and course of the disease, the patient's health and response to treatment and the judgment of the treating physician. Accordingly, the dosages of the conjugates and any accompanying compounds should be titrated to the individual patient. Nevertheless, an effective dose of the conjugates may be in the range of from about 1 to about 100 mg/m 2 drug or from about 500-5000 mg/m 2 antibody.
• An effective dose of the conjugates containing ligands other than antibodies may be in the range of from about 1 to about 100 mg/m 2 drug or from about 1 to about 100 mg/m 2 ligand.
• the carbon-branched linker is derived from a bis-carboxylic acid, which also contains a protected amine functionality.
• the nitrogen-branched linker is derived from an oligoamine, differentially protected in such a way that all but one amino group are elaborated to yield terminal N, N-dialkanoylhydrazide groups. The remaining amino group is elaborated to yield a terminal thiol acceptor. Condensation of the multiple hydrazides with an drug containing an aldehyde or ketone group yields a multiple acylhydrazone of the drug.
• Conjugation of the linker to the targeting ligand is accomplished by the reaction of free thiol groups of the ligand, generated under controlled atmospheric conditions, with the terminal thiol acceptor of the linker.
• Z is carbobenzoxy
• DCC is dicyclohexylcarbodiimide
• BOC is t-butoxy carbonyl
• TFA is trifluoroacetic acid
• DOX is doxorubicin.
• Solvents were partially removed by rotary evaporation. The oil was dissolved in 100 ml ethyl acetate, then extracted three times with 100 ml 10% citric acid, three times with 100 ml saturated aqueous sodium bicarbonate, and three times with 100 ml H2O. The organic layer was dried over sodium sulfate and rotary evaporated to a foam. This was purified by flash chromatography on silica gel (2 in. X 11 in.) with CH 2 CI 2 -acetic acid-methanol
• Solvents were removed by rotary evaporation. The oil was dissolved in 100 ml ethyl acetate, then extracted three times with 100 ml 10% citric acid, three times with 100 ml saturated aqueous sodium bicarbonate, and three times with 100 ml H 2 O. The organic layer was dried over sodium sulfate and rotary evaporated to a foam. This was
• DOX ⁇ HCl (1.34 g, 2.30 mmole) were dissolved in 600 ml methanol over a period of 3 hours. The reaction was concentrated to 100 ml by rotary evaporation, then stirred for 2.5 days. The reaction was further
• N-hydroxysuccinimide ester of maleimidopropionic acid 300 mg, 1.13 mmole was prepared as in the
• the organic layer was washed three times with 50 ml 10% citric acid, three times with 50 ml saturated NaHCO 3 , and three times with 50 ml H 2 O.
• the organic layer was concentrated to a foam, which was purified by flash chromatography on silica gel (1 in. X 12 in.) with
• FTIR 3292, 2980, 1720, 1690, 1484, 1368, 1248, 1162, 1048, 1016, 880, 773, 574 cm -1 .
• FTIR 3300, 2982, 1738, 1708, 1680 (sh), 1498, 1394, 1368, 1248, 1162, 1048, 1016, 72, 696 cm -1 .
• FTIR 3328, 2980, 1698, 1672, 1500, 1368, 1300, 1252, 1162, 778, 692 cm -1 .
• Method B On a scale >3 g, the same procedure was utilized for the DTT reaction, with the exception that the MAb solutions were de-oxygenated by bubbling with Ar. Purification after DTT reduction was accomplished by ultrafiltration in a Filtron Minisette unit. The
• Minisette was fitted with two Filtron 30K cassettes and was connected to a Watson Marlow 604S pump with Bioprene tubing.
• the MAb solution was ultrafiltered at 0°C under Ar against Ar-bubbled PBS, pH 7.0 (eluant flow rate 100-150 ml/min., 25 psi backpressure), while continually monitoring eluant for thiol content as above.
• a 6.6 g batch of BR96 (550 ml at 75.3 uM) yielded 6.1 g reduced BR96 (800 ml at 47.6 uM MAb, 398 uM thiol) for a yield of 92% and thiol titer of 8.4 mole thiol groups/mole BR96.
• Conjugate was purified at 4°C by percolation (approximately 2 ml/min.) through a 1" ⁇ 36" Bio-Beads column (initially prepared by swelling and packing in methanol, then equilibrated in H 2 O, and finally PBS, pH 7.0). The purified conjugate was filtered again through a 0.22u sterile filter to yield 155 ml of BR96-2b (BR96, 39.13 uM; DOX, 589.0 uM; MR, 15.1 mole DOX/mole BR96; yield, 100%). Conjugate was frozen in liquid n 2 and stored at -80°C.
• Example 70 Example 70
• MAb BR64 murine IgG 1
• MAb BR96 mouse/human
• Trail et al. 1992; Trail et al., 1993; Willner, D., Trail, P.A., Hofstead, S.J., King, H.D., Lasch, S.J., Braslawsky, G.R., Greenfield, R.S., Kaneko, T. and
• DOX/MAb molar ratios were prepared with both chimeric BR96 and control human IgG.
• L2987 is a human lung line which expresses the BR64 and BR96 antigens. L2987 was obtained from I. Hellst ⁇ m (Bristol-Myers Squibb, Seattle, WA).
• In vitro cytotoxicity assays were performed as described previously (Trail et al., 1992). Briefly, monolayer cultures of L2987 human carcinoma cells were harvested using trypsin-EDTA (GIBCO, Grand Island, NY), and the cells counted and resuspended to 1 ⁇ 10 5 /ml in RPMI-1640 containing 10% heat
• mice of Balb/c background (Balb/c nu/nu; Harlan Sprague-Dawley, Indianapolis, IN) were used in thse studies.
• mice were housed in Thoren caging units on sterile bedding with controlled temperature and humidity.
• T-C is defined as the median time (days) for treated tumors to reach 500mm 3 size minus the median time for control tumors to reach 500mm 3 in size and TVDT is the time
• Partial tumor regression reflects a decrease in tumor volume to ⁇ 50% of the initial tumor volume
• complete tumor regression refers to a tumor which for a period of time is not palpable; and cure is defined as an established tumor which is not palpable for a period of time ⁇ 10 TVDT's.
• Treatments were administered by the ip or iv route on various schedules as denoted. DOX was diluted in normal saline and MAb and MAb-DOX conjugates were diluted in PBS. All therapy was administered on a mg/kg basis calculated for each animal and doses are presented as mg/kg/injection. Control animals were not treated.
• Doses of immunoconjugate are reported based on the drug (equivalent DOX) and antibody content.
• the maximum tolerated dose (MTD) for a treatment regimen is defined as the highest dose on a given schedule which resulted in ⁇ 20% lethality.
• n is a positive integer
• the conjugate molar ratios of the various singly branched conjugates ranged from 11-16 and that of the doubly branched
• DOXHZN conjugates were 2-20 fold (IC 50 values of 0.1-1.0 uM equivalent DOX), and the doubly branched conjugates (IC50 of 0.2uM) were 10 fold, more potent than the straight chain DOXHZN conjugate BMS-182248 (2 uM DOX).
• BMS-182248 refers to the straight chain conjugate as disclosed by
• linker chemistries which are extremely stable in the extracellular environment yet liberate drug efficiently upon internalization into antigen-expressing cells.
• One method for assessing extracellular stability, and in part, intracellular hydrolysis rates is to evaluate antigen-specific
• the MCDOXHZN (BMS-182248) conjugate was less potent than the branched hydrazone, MB-Glu-(DOX) 2 ; BMS-187852, conjugate during the first 24 h of exposure.
• the potency of the MCDOXHZN conjugate was increased over time whereas that of the branched DOXHZN remained essentially unchanged over 48h of exposure.
• hydrazone conjugates increased with longer exposure times.
• the increase in potency of non-binding conjugates likely reflects cytotoxicity of DOX itself following release of DOX from the conjugate over time.
• the potency of both the linear and branched hydrazone conjugates increased in parallel, suggesting that the extracellular stability of these conjugates was quite similar.
• the BR96 branched hydrazone conjugates were more potent in vitro at short exposure times than were the MCDOXHZN (BMS-182248) conjugates.
• the extracellular stability of the branched conjugates was not different from that of the straight chain MCDOXHZN conjugate.
• BR96 and IgG conjugates were produced using six different branched linkers and the conjugates evaluated for
• the molar ratio of the BMS-187852 conjugates varied from 13.7-15. As shown in Table 3, 3 lots
• BMS-187852 were tested.
• the optimal dose for both BMS-187852 and BMS-182248 was 2.5 mg/kg DOX.
• the branched conjugate was approximately 2 fold more potent than BMS-182248 (RG) on a MAb basis.
• the antitumor activity of BMS-187852 was antigen-specific
• BMS-187853 conjugate Two lots of BMS-187853 conjugate (molar ratios approximately 11.5) were evaluated against established L2987 lung tumor xenografts. The antitumor activity of the 2 lots was similar; both produced optimal antigenspecific antitumor activity at doses of approximately 2.0 mg/kg DOX, 45 mg/kg BR96. Overall, these conjugates were similar to BMS-182248 (RG) on a DOX and 2 fold more potent on a MAb basis.
• BMS-188077 The DOX/BR96 molar ratio of BMS-188077 conjugates was in the range of 14.6-16.1. As shown in Table 5, antigen-specific antitumor activity was observed for BMS-188077. BMS-188077 was of similar potency as BMS- 182248 (RG) on a DOX equivalent basis but due to the increase in the molar ratio, approximately 2 fold more potent on a MAb basis.
• BMS-189099 conjugates were evaluated in parallel with non-binding IgG conjugates (BMS-188078) produced with the same linker chemistry.
• the mole ratios of the BR96 conjugates were in the range of 14.5-15.5.
• the antitumor activity of BMS-189099 and non-binding conjugates is presented in Table 6. Antigen-specific antitumor activity was observed in vivo.
• the BMS-189099 conjugates were of similar potency as BMS-182248 (RG) on a DOX basis but approximately 2 fold more potent on a MAb basis.
• the molar ratios of the BMS-189812 conjugates were in the range of 11-15 moles DOX/moles BR96. Data for the antitumor activity of BMS-189812 is summarized in Table 7.
• the optimal dose of BMS-189812 was approximately 2 mg/kg DOX, 50 mg/kg BR96.
• the potency on a DOX basis was similar to BMS-182248 (RG) and the conjugate was two fold more potent on a MAb basis.
• the BMS-190385 conjugates demonstrated antigen-specific activity in vivo.
• the antitumor activity of BMS-190385 conjugates is presented in Table 8.
• two lots of BR96-DOX conjugate are currently being evaluated against established L2987 lung xenografts. Antigen-specific antitumor activity was observed.
• the optimal dose of thse conjugates is 2 mg/kg DOX, 60 mg/kg BR96. This is similar to that of BMS-182248 on a DOX basis and slightly more potent on a MAb basis.
• the branched chain DOXHZN conjugates evaluated herein typically had molar ratios in the range of 11-15. This is 1.5-1.8 fold higher than the molar ratio

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