Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07K—PEPTIDES
  • C07K16/00—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies
  • C07K16/18—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans
  • C07K16/28—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants
  • C07K16/2863—Immunoglobulins [IGs], e.g. monoclonal or polyclonal antibodies against material from animals or humans against receptors, cell surface antigens or cell surface determinants against receptors for growth factors, growth regulators
• • 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
  • A61K47/6801—Drug-antibody or immunoglobulin conjugates defined by the pharmacologically or therapeutically active agent
  • A61K47/6803—Drugs conjugated to an antibody or immunoglobulin, e.g. cisplatin-antibody conjugates
• • 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
  • A61K47/6835—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 the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site
  • A61K47/6849—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 the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting a receptor, a cell surface antigen or a cell surface determinant
• • 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
  • A61K47/6835—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 the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site
  • A61K47/6851—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 the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting a determinant of a tumour cell
  • A61K47/6855—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 the modifying agent being an antibody or an immunoglobulin bearing at least one antigen-binding site the antibody targeting a determinant of a tumour cell the tumour determinant being from breast cancer cell
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/505—Medicinal preparations containing antigens or antibodies comprising antibodies

Definitions

• EGFR Epidermal growth factor receptor
• Activation of the EGFR autocrine growth pathway in cancer cells can be attributable to several mechanisms, namely, EGFR overexpression, increased concentration of ligand(s), decreased phosphatase activity, decreased receptor turnover, and the presence of aberrant receptors.
• Administration of blocking anti-EGFR antibodies only is not so therapeutic to those cancers independent to ligand binding.
• Currently-used anticancer drugs are unable to recognize tumor cells from normal cells. The amount of an anticancer drug required to achieve a clinically effective level of cell kill often causes severe damage to actively propagating nonmalignant cells such as cells of the gastrointestinal tract and bone marrow, resulting in a variety of undesirable side effects.
• the present invention features additional anti-EGFR immunoconjugates and methods of using the same for suppressing the growth of tumor cells and for treating cancers of epithelial origin.
• the present invention features EGFR-binding molecules.
• Each molecule comprises an antigen-binding fragment of an anti-EGFR monoclonal antibody and a cytotoxic agent.
• an EGFR-binding molecule of the present invention is a monoclonal antibody LAl or LA22 conjugated with a cytotoxic agent.
• the present invention also features humanized or engineered antibodies comprising an antigen-binding fragment of LAl or LA22 conjugated with mitomycin C, pingyangmycin, or other anti-cellular agents.
• the present invention features other anti-EGFR antibodies conjugated with mitomycin C or pingyangmycin. These antibodies can be monoclonal antibodies, human antibodies, humanized or engineered antibodies, synthetic antibodies, or single chain antibodies.
• the EGFR-binding molecules or antibodies of the present invention can be used to kill or inhibit the growth of cancer cells. These methods comprise contacting cancer cells with an EGFR-binding molecule or antibody of the present invention.
• the EGFR-binding molecules or antibodies of the present invention can be used to treat cancers. These methods comprise administrating an effective amount of an EGFR-binding molecule or antibody of the present invention to a subject in need thereof. Cancers or cancer cells amenable to the present invention include those of epithelial origin.
• the present invention also features pharmaceutical compositions comprising an EGFR-binding molecule or antibody of the present invention.
• FIGURE 1 demonstrates the cytotoxic effects of anti-EGFR monoclonal antibodies conjugated with pingyangmycin or mitomycin C on human epidermoid carcinoma cells.
• FIGURE 2 illustrates the dose-dependent cytotoxic effect of monoclonal antibody LA22 conjugated with pingyangmycin or mitomycin C on human epidermoid carcinoma cells.
• FIGURE 4 shows the dose-dependent cytotoxic effect of monoclonal antibody
• FIGURE 5 demonstrates the dose-dependent cytotoxic effect of monoclonal antibody LAl conjugated with pingyangmycin or mitomycin C on human lung cells.
• FIGURE 6 illustrates the in vivo tumor toxicity effect of LA22-MMC on female Balb/c mice.
• FIGURE 6A shows the treatment scheme of LA22-MMC immunoconjugate on A431 xenografts and the inhibitory effect of tumor growth in vivo.
• FIGURE 6B summarizes the tumor size and percent of tumor inhibition of each of the treatment groups (control, MMC, and LA22-MMC at 0.0032 mg/kg and 0.08 mg/kg).
• FIGURE 7 shows the biodistribution of LA22-MMC immunoconjugate on tumor-bearing mice after 125 I-radiolabeling and immunoscintigraphy.
• FIGURE 8 compares the in vitro cytotoxic effect of LA22-MMC immunoconjugate on human epidermoid carcinoma cells with Erbitux -MMC and
• Herceptin ® -MMC Herceptin ® -MMC.
• the present invention features anti-EGFR monoclonal antibodies LAl or
• LA22 conjugated with cytotoxic or anticellular agents Both LAl and LA22 are commercially available from Upstate USA, Inc., Charlottesville, VA. Monoclonal antibody LA22 is also described in U.S. Patent No. 5,459,061, which is incorporated herein by reference in its entirety.
• Non-limiting examples of suitable cytotoxic or anti-cellular agents include chemotherapeutic agents, radioisotopes, and cytotoxins.
• Specific examples of cytotoxic or anti-cellular agents include, but are not limited to, cytotoxic antibiotics (such as mitomycin C or pingyangmycin), hormones (such as steroids), anti-metabolites (such as cytosine arabinoside, fluorouracil, methotrexate or aminopterin), anthracycline, vinca alkaloids, demecolcine, etoposide, mithramycin, alkylating agents (such as chlorambucil or melphalan), doxorubicin, daunomycin, methotrexate, vinblastine, neocarzinostatin, macromycin, trenimon, ⁇ -amanitin, ricin, ricin A-chain, daunorubicin, taxol, ethiduim bromide, mitomycin, etoposide, ten
• LAl or LA22 monoclonal antibodies can also be conjugated to an anti-cancer pro-drug activating enzyme capable of converting a pro-drug to its active form. See, for example, U.S. Patent No. 4,975,287, which is incorporated herein by reference in its entirety.
• Linking or coupling one or more cytotoxic moieties to an antibody can be achieved by a variety of mechanisms, for example, covalent binding, affinity binding, intercalation, coordinate binding and complexation.
• Preferred binding methods are those involving covalent binding, such as using chemical cross-linkers, natural peptides or disulfide bonds.
• the covalent binding can be achieved either by direct condensation of existing side chains or by the incorporation of external bridging molecules.
• Many bivalent or polyvalent agents are useful in coupling protein molecules to other proteins, peptides or amine functions.
• Examples of coupling agents are carbodiimides, diisocyanates, glutaraldehyde, diazobenzenes, and hexamethylene diamines. This list is not intended to be exhaustive of the various coupling agents known in the art but, rather, is exemplary of the more common coupling agents that may be used.
• an antibody is first derivatized, following by attachment of the cytotoxic component to the derivatized product.
• the term "derivatize” refers to the chemical modification of the antibody substrate with a suitable cross-linking agent.
• cross-linking agents include the disulfide-bond containing linkers SPDP (N-succinimidyl-3-(2-pyr ⁇ dyldithio)propionate) and SMPT (4-succinimidyl-oxycarbonyl- ⁇ -methyl- ⁇ (2-pyridyldithio)toluene).
• Biologically-releasable bonds can also be employed in constructing a clinically-active immunoconjugate, such that the cytotoxic moiety is capable of being released from the antibody once it has entered the target cell.
• Numerous types of linking constructs are known, including simply direct disulfide bond formation between sulfhydryl groups contained on amino acids such as cysteine, or otherwise introduced into respective protein structures, and disulfide linkages using available or designed linker moieties.
• Numerous types of disulfide-bond containing linkers are known, which can successfully be employed to conjugate cytotoxic moieties to antibodies.
• the present invention also features anti-EGFR molecules comprising the antigen-binding fragments of LA22 or LAl monoclonal antibodies conjugated with cytotoxic or anticellular agents. These antigen-binding fragments can include or consist of the scFv, diabody, minibody, Fab, F(ab') 2 , or Fv fragments of LA22 or LAl 1 monoclonal antibodies.
• the anti-EGFR molecules of the present invention are humanized or engineered monoclonal antibodies prepared from monoclonal antibodies LA22 or LAl. Humanized or engineered antibodies are particularly desirable for therapeutic treatment of human subjects.
• Humanized or engineered forms of non-human (e.g., murine) antibodies are chimeric immunoglobulins, or antigen-binding fragments thereof (such as scFv, diabody, minibody, Fab, or F(ab') 2 ), which contain minimal sequence derived from non-human immunoglobulin.
• Humanized or engineered antibodies are derived from human immunoglobulins in which the residues forming the complementary determining regions (CDRs) are replaced by the residues from CDRs of a non-human antibody, such as LA22 or LAl.
• CDRs complementary determining regions
• Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues.
• humanized or engineered antibodies which recognize a selected epitope can be generated using a technique referred to as "guided selection.”
• a selected non-human monoclonal antibody e.g., a murine antibody
• the methods, as described in U.S. Patent Nos. 6,639,055 and 6,794,132, both of which are incorporated herein by reference, can also be used to prepare humanized or engineered antibodies.
• the present invention features other anti-EGFR antibodies conjugated with mitomycin C, pingyangmycin, or other cytotoxic antibiotics.
• Antibodies suitable for this purpose include, but are not limited to, polyclonal, monoclonal, monospecific, poly-specific, non-specific, humanized or engineered, human, single-chain, chimeric, synthetic, recombinant, hybrid, mutated, grafted, or in vitro generated antibodies.
• an antibody of the present invention binds to an epitope in the extracellular domain of EGFR and has an EGFR-binding affinity of at least 10 "5 M “1 , 10 "6 M “1 , 10 "7 M “1 , 10 “ 8 M “1 , 10 “9 M “1 , 10 '10 M '1 , or stronger.
• the scFv, diabody, minibody, Fab, F(ab') 2 , or Fv fragments of these antibodies can also be used for the conjugation of mitomycin C, pingyangmycin, or other cytotoxic antibiotics.
• a pharmaceutical composition of the present invention typically includes an EGFR-binding molecule of the present invention (e.g., mitomycin C- or pingyangmycin-conjugated LA22 or LAl) and a pharmacologically-acceptable carrier.
• EGFR-binding molecule of the present invention e.g., mitomycin C- or pingyangmycin-conjugated LA22 or LAl
• pharmacologically-acceptable carrier includes any and all solvents, dispersion media, coatings, anti-bacterial and anti-fungal agents, isotonic and absorption delaying agents and the like. The use of such media and agents for pharmaceutically-active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the vectors or cells of the present invention, its use in therapeutic or prophylactic compositions is contemplated. Supplementary active ingredients also can be incorporated into the compositions.
• Administration of a pharmaceutical composition of the present invention can be by way of any common route so long as the target tissue is available via that route. This includes oral, nasal, buccal, rectal, vaginal or topical. Alternatively, administration may be by orthotopic, intradermal, subcutaneous, intramuscular, intraperitoneal, intratumoral, circumferentially, catheterization, or intravenous injection.
• a pharmaceutical composition can also be administered parenterally or intraperitoneally.
• Solutions of the active compounds as free base or pharmacologically- acceptable salts can be prepared in water suitably mixed with a surfactant, such as hydroxypropylcellulose.
• Dispersions can also be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations may contain a preservative to prevent the growth of microorganisms.
• the pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions.
• the form is sterile and fluid to the extent that easy syringability exists. It is preferably also stable under the conditions of manufacture and storage and preserved against the contaminating action of microorganisms, such as bacteria and fungi.
• the carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), suitable mixtures thereof, or vegetable oils.
• the proper fluidity can be maintained, for example, by the use of a coating, such as lecithin, by the maintenance of the required particle size in the case of dispersion, or by the use of surfactants.
• the prevention of the action of microorganisms can be brought about by various anti-bacterial or anti-fungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal or the like.
• isotonic agents for example, sugars or sodium chloride.
• Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin.
• Sterile injectable solutions can be prepared by incorporating an EGFR-binding molecule of the present invention in the required amount in an appropriate solvent with various other ingredients enumerated above, as required, followed by filtered sterilization.
• dispersions are prepared by incorporating the various sterilized active ingredients into a sterile vehicle, which contains the basic dispersion medium and the required other ingredients from those enumerated above.
• the preferred methods of preparation are vacuum-drying or freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof.
• an EGFR-binding molecule of the present invention can be incorporated with excipients and used in the form of non-ingestible mouthwashes and dentifrices.
• a mouthwash may be prepared incorporating the active ingredient in the required amount in an appropriate solvent, such as a sodium borate solution (Dobell's Solution).
• an EGFR-binding molecule may be incorporated into an anti-septic wash containing sodium borate, glycerin and potassium bicarbonate.
• An EGFR-binding molecule may also be dispersed in dentifrices, including: gels, pastes, powders, or slurries.
• An EGFR- binding molecule may be added in a therapeutically or prophylactically effective amount to a paste dentifrice that may include water, binders, abrasives, flavoring agents, foaming agents, or humectants.
• compositions of the present invention may be formulated in a neutral or salt form.
• Pharmaceutically-acceptable salts include the acid addition salts formed with the free amino groups of the protein or formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed with the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, histidine, procaine and the like.
• compositions or solutions Upon formulation, compositions or solutions will be administered in a manner compatible with the dosage formulation and in such amount as is therapeutically or prophylactically effective.
• the formulations are easily administered in a variety of dosage forms such as injectable solutions, drug release capsules and the like.
• parenteral administration in an aqueous solution for example, the solution can be suitably buffered if necessary and the liquid diluent first rendered isotonic with sufficient saline or glucose.
• aqueous solutions are especially suitable for intravenous, intramuscular, subcutaneous, and intraperitoneal administration.
• sterile aqueous media which can be employed will be known to those of skill in the art in light of the present disclosure.
• one dosage could be dissolved in 1 ml of isotonic NaCl solution and either added to 1000 ml of hypodermoclysis fluid or injected at the proposed site of infusion, (see, for example, REMINGTON'S PHARMACEUTICAL SCIENCES (15th Edition), pages 1035- 1038 and 1570-1580). Some variation in dosage will necessarily occur depending on the condition of the subject being treated.
• the EGFR-binding molecules of the present invention can be used to kill or inhibit the growth of cancer cells.
• the EGFR-binding molecules of the present invention can also be used to treat cancers in patients or animals.
• cancers that are amenable to the present invention include, but are not limited to, cancers of epithelial origin, such as glioblastoma, cancer of the lung, breast, head and neck, and bladder, or other epidermoid cancers.
• the EGFR-binding molecule of the present invention.
• the EGFR-binding molecule would be provided in an amount effective to kill or inhibit proliferation of the tumor cells.
• the EGFR-binding molecules can also be combined with other traditional therapies to treat cancers.
• Agents or factors suitable for use in a combined therapy are any chemical compound or treatment method that induces DNA damage when applied to a cell. Such agents and factors include radiation and waves that induce DNA damage such as, ⁇ - irradiation, X-rays, UV-irradiation, microwaves, electronic emissions, and the like.
• Chemotherapeutic agents contemplated to be of use include, e.g., adriamycin, 5- fluorouracil (5FU), etoposide (VP- 16), camptothecin, actinomycin-D, mitomycin C, cisplatin (CDDP), and in some cases, hydrogen peroxide.
• LA22 hybridoma (ATCC No. HB 10342) cells at 2x10 4 cell density were injected to Balb/c nude mice. Monoclonal antibodies from ascites was purified using Protein G affinity agarose beads (Upstate, Lake Placid, NY). Briefly, ascites fluid was diluted 1 : 1 with PBS (pH 7.4) and centrifuged at 14,00Og for 4 min. Supernatant was carefully collected and loaded onto a Protein G column (containing 2 mL Protein G agarose) and a 10 mL PBS was then applied to the column to wash unbound components.
• Bound mAb LA22 was eluted with elution buffer (50 mM glycine-HCl, pH 2.7) and transferred into PBS (pH 7.4) by Desalting Column (Pierce, Rockford, IL). Aliquots were analyzed for purity with SDS- PAGE. Concentration of mAb LA22 was determined to be at 1 mg/ml of mouse IgG, which was equivalent to an O.D. (optical density) reading of 1.40. [0050] The A431 human epidermoid carcinoma cells, which express large quantities of EGFR, and A549 human lung adenocarcinoma cells were used for in vitro cytotoxicity assays.
• DMEM Dulbecco's Modified Eagle medium
• FBS fetal bovine serum
• MMC (10 mg in 5 mL PBS) was reacted with 0.9 mL of SPDP (Pierce, Rockford, IL) stock (10 mg in 1 mL DMF) at 4°C for 6 h. The resulting solution was stored in small aliquots at -80°C until further use.
• mAb LA22 5.5 mg in 3 mL of PBS
• mAb LAl was reduced by adding 46 ⁇ L of 2-iminothiolane (4.4 mg dissolved in 1 mL DMF) for 1 h under nitrogen. The reduced antibody was purified by size exclusion chromatography using a desalting column (Pierce, Rockford, IL), that was pre-equilibrated with PBS.
• LA22-MMC or LA22-PMC
• FIGURE 2 illustrates that anti-EGFR mAb LA22-PYM or LA22- MMC induced the death of A431 human cancer cells in a dose-dependent manner.
• Another LA22-MMC cytotoxicity assay was performed with additional controls.
• the A431 cells, as well as human lung adenocarcinoma A549 cells were plated (2x10 3 cells/well, 100 ⁇ L/well) in 96-well cell culture plates (Corning, Corning, NY) in the presence of DMEM medium and 10% FBS for 4 h at 37 °C, 5% CO 2 .
• MMC, naked mAb LA22 or LA22-MMC immunoconjugate in serum-free DMEM medium (100 ⁇ L) were added onto the individual wells and incubated for 4 days at 37°C and 5% CO 2 . The supernatants were discarded first. For dead cells control, 100 ⁇ L of cold 95% ethanol was added into the well for 1 min then discarded.
• MTT solutions (USB, Cleveland, OH; 10% in DMEM medium) were added (100 ⁇ L/well) and incubated for 4 h at 37°C. The supernatants were discarded and DMSO was added (100 ⁇ L/well) to dissolve the precipitates. Optical density was read at 570 nm using a microplate reader (Bio-Rad, Hercules, CA). [0056] , The above-mentioned inhibition of A431/A549 in vitro cell growth was used as a measure for drug activity in vitro and was determined by exposing cultured cells (2x10 3 cells/well) for 4 days at 37°C with MMC, LA22-MMC or LA22.
• the tested MMC concentrations ranged from 0.03 ⁇ g/mL to 30 ⁇ g/mL.
• the dosage of the LA22-MMC conjugate for cytotoxicity was calculated according to the total amount of MMC added in chemical coupling reaction. Because the efficiency of chemical coupling reactions was not 100%, theoretically the real MMC concentration linked to LA22 was lower than indicated concentration. The dosage of LA22 was the same as LA22-MMC.
• Non-specific mouse IgG (as a negative control) was labeled with MMC and added into A431 cells to evaluate its cytotoxicity on cell growth in vitro. The result showed that non-specific mouse IgG-MMC immunoconjugates did not kill cultured cells as efficiently as LA22-MMC, which proved that the cytotoxicity of LA22-MMC can be mediated via LA22-EGFR binding (data not included).
• A549 cell line (ATCC No. CCL-185).
• A549 cells were seeded at 2,000 cells/well of 96-well plate in DMEM-10% FBS.
• various amounts of LAl, LAl-MMC, or MMC-SPDP were added to the cell cultures.
• the cell numbers in each well were determined by MTT assay. The numbers were expressed as the percentage of the cell death (FIGURE 5).
• LAl-MMC induced the death of A549 human lung cancer cells in a dose-dependent manner. No significant cell death was observed with mAb LAl alone. Conjugation with mitomycin C significantly increased the cell killing potency of LAl.
• mice treated with LA22-MMC (0.08 mg/kg) inhibited tumor growth in vivo when compared with control untreated mice.
• MMC (0.08 mg/kg) injection was potent to inhibit tumor growth, the efficiency was much lower than LA22-MMC (0.08 mg/kg), which suggested the great advantage of LA22-mediated specific tumor targeting.
• Low dosage administration (0.0032 mg/kg) of LA22-MMC was not potent as the high-dosage of LA22-MMC administration (0.08 mg/kg), which suggested the dose-dependent effect of LA22-MMC immunoconjugate.
• mice were sacrificed and the tumors were weighed (FIGURE 6B).
• the nude mice- bearing A431/A549 xenografts were injected intravenously with 17.6 MBq ( ⁇ 20 ⁇ g, 0.3 mL) of 125 I-LA22-MMC, and placed prone on a two-head ⁇ -camera (E.CAM, Siemens, Kunststoff, Germany) equipped with a parallel-hole, low-energy, high-resolution collimator.
• the posterior images were acquired at different time points post-injection for the visual observation of in vivo distribution of LA22-MMC, and stored digitally in a 128 x 128 matrix.
• the acquisition count limits were set at 1000 K.
• LA22-MMC first distributed in the circulation system and blood-rich tissues such as liver or heart (4h imaging); gradually the labeled immunoconjugates enriched on the tumor sites (1 day to 4 days). After 4 days, LA22-MMC mainly enriched on the tumor sites.
• Erbitux ® and Herceptin ® two commercially-available mAb drugs for cancer therapy, target EGFR and HER2, respectively. Both EGFR and HER2 belong to the ErbB receptor family (Mendelsohn, J. et ah, Oncogene, 19:6550-7565, 2000).
• Erbitux ® and Herceptin ® an in vitro cytotoxicity assay using the MTT method was conducted. The conjugation of MMC with Erbitux ® (ImClone, New York, NY) or Herceptin ® (Genentech, San Francisco, CA) or mouse IgG was done as described above.
• Erbitux ® and Herceptin ® were labeled with MMC and evaluated for their cytotoxicities.
• A431 (FIGURE 8A) or A549 (FIGURE 8B) cells were seeded into 96-well cell culture plates. Naked antibodies or immunoconjugates were added to wells and incubated for 4 days at 37°C and 5% CO 2 . Viable cells were measured using the MTT assay. Using similar antibody concentrations, LA22-MMC prodrug killed A431 and A549 cells more efficiently than Erbitux ® -MMC or Herceptin ® -MMC (see FIGURES 8A & 8B) .

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