Potent conjugates and hydrophilic linkers

Abstract

Linkers for binding drugs to cell binding agents are modified to hydrophilic linkers by incorporating a polyethylene glycol spacer. The potency or the efficacy of the cell-binding agent-drug conjugates is surprisingly enhanced several folds in a variety of cancer cell types, including those expressing a low number of antigens on the cell surface or cancer cells that are resistant to treatment. A method for preparing maytansinoids bearing a thioether moiety and a reactive group which allows the maytansinoid to be linked to a cell-binding agent in essentially a single step is also provided.

1 . A compound of formula (1) or (1′):
   Z—X l —(—CH 2 —CH 2 —O—) n —Y p -D  (1)
 
   D-Y p —(—CH 2 —CH 2 —O—) n —X l —Z  (1′)
 
 wherein: 
 Z represents a reactive functionality that can form an amide or a thioether bond with a cell-binding agent; 
 D represents a drug; 
 X represents an aliphatic, an aromatic or a heterocyclic group attached to the cell-binding agent via a thioether bond, an amide bond, a carbamate bond, or an ether bond; 
 Y represents an aliphatic, an aromatic or a heterocyclic group attached to the drug via a covalent bond selected from the group consisting of a thioether bond, an amide bond, a carbamate bond, an ether bond, an amine bond, a carbon-carbon bond and a hydrazone bond; 
 l is 0 or 1; 
 p is 0 or 1; and 
 n is an integer from 1 to 2000. 
 
     
     
         2 . A cell-binding agent cytotoxic drug conjugate of formula (2) or (2′):
   CB—[X l —(—CH 2 —CH 2 —O—) n —Y p -D] m   (2)
 
   [D-Y p —(—CH 2 —CH 2 —O—) m —X l ] m —CB  (2′)
 
 wherein; 
 CB represents a cell-binding agent; 
 D represents a drug; 
 X represents an aliphatic, an aromatic or a heterocyclic group attached to the cell-binding agent via a thioether bond, an amide bond, a carbamate bond, or an ether bond; 
 Y represents an aliphatic, an aromatic, or a heterocyclic group attached to the drug via a covalent bond selected from the group consisting of a thioether bond, an amide bond, a carbamate bond, an ether bond, an amine bond, a carbon-carbon bond and a hydrazone bond; 
 l is 0 or 1; 
 p is 0 or 1; and 
 m is an integer from 2 to 15; and 
 n is an integer from 1 to 2000. 
 
     
     
         3 . A compound of formula (3) or (3′):
   Z—X l —(—CH 2 —CH 2 O—) n —Y-D  (3)
 
   D-Y—(—CH 2 —CH 2 O—) n —X l —Z  (3′)
 
 wherein: 
 Z represents a reactive functionality that can form an amide or a thioether bond with a cell-binding agent; 
 D represents a drug; 
 X represents an aliphatic, an aromatic or a heterocyclic group attached to the cell-binding agent via a thioether bond, an amide bond, a carbamate bond, or an ether bond; 
 Y represents an aliphatic, non-aromatic heterocyclic or aromatic heterocyclic group attached to the drug via a disulfide bond; 
 l is 0 or 1; and 
 n is an integer from 1 to 14. 
 
     
     
         4 . A cell-binding agent cytotoxic drug conjugate of formula (4) or (4′):
   CB—(X l —(—CH 2 —CH 2 O—) n —Y-D) m   (4)
 
   [D-Y—(—CH 2 —CH 2 O—) n —X l ] m —CB  (4′)
 
 wherein: 
 CB represents a cell-binding agent; 
 D represents a drug; 
 X represents an aliphatic, an aromatic or a heterocyclic group attached to the cell-binding agent via a thioether bond, an amide bond, a carbamate bond, or an ether bond; 
 Y represents an aliphatic, an aromatic or a heterocyclic group attached to the drug via a disulfide bond; 
 l is 0 or 1; and 
 m is an integer from 3 to 8; and 
 n is an integer from 1 to 14. 
 
     
     
         5 . The conjugate of  claim 2 , wherein said cell-binding agent is an antibody, a single chain antibody, an antibody fragment that preferentially binds to a target cell, a monoclonal antibody, a single chain monoclonal antibody, a monoclonal antibody, a bispecific antibody, fragment that specifically binds to a target cell, antibody mimics adnectins, DARPins, a lymphokine, a cytokine, a hormone, a growth factor, an enzyme, or a nutrient-transport molecule. 
     
     
         6 . The conjugate of  claim 2 , wherein said cell-binding agent is a resurfaced monoclonal antibody, a resurfaced single chain monoclonal antibody, or a resurfaced monoclonal antibody fragment that preferentially binds to a target cell. 
     
     
         7 . The conjugate of  claim 2 , wherein said cell-binding agent is a humanized monoclonal antibody, a humanized single chain monoclonal antibody, or a humanized monoclonal antibody fragment that preferentially binds to a target cell. 
     
     
         8 . The conjugate of  claim 5 , wherein said antibody is a chimeric antibody, a chimeric antibody fragment, a domain antibody, or a domain antibody fragment thereof. 
     
     
         9 . The conjugate of  claim 5 , wherein said antibody is MY9, anti-B4, EpCAM, CD2, CD3, CD4, CD5, CD6, CD11, CD19, CD20, CD22, CD26, CD30, CD33, CD37, CD38, CD40, CD44, CD56, CD79, CD105, CD138, EphA receptors, EphB receptors, EGFR, EGFRvIII, HER2, HER3, mesothelin, cripto, alpha v beta 3 , alpha v beta 5 , alpha v beta 6  integrin or C242. 
     
     
         10 . The conjugate of  claim 5 , wherein said antibody is a humanized, a human or a resurfaced antibody selected from My9-6, B4, C242, N901, DS6, EphA2 receptor, CD38, IGF-IR, CNTO 95, B-B4, trastuzumab, pertuzumab, bivatuzumab, sibrotuzumab, or rituximab. 
     
     
         11 . The conjugate of  claim 2 , wherein said cell-binding agent binds to target cells selected from tumor cells; virus infected cells, microorganism infected cells, parasite infected cells, autoimmune cells, activated cells, myeloid cells, activated T-cells, B cells, or melanocytes; cells expressing one or more of IGF-IR, CanAg, EGFR, MUC1, MUC16, VEGF, TF, MY9, anti-B4, EpCAM, CD2, CD3, CD4, CD5, CD6, CD11, CD 11a, CD18, CD19, CD20, CD22, CD26, CD30, CD33, CD37, CD38, CD40, CD44, CD56, CD70, CD79, CD105, CD138, EphA receptors, EphB receptors, EGFRvIII, HER2/neu, HER3, mesothelin, cripto, alpha v beta 3 integrin, alpha v beta 5 integrin, alpha v beta 6  integrin, Apo2, and C242 antigens; or cells expressing insulin growth factor receptor, epidermal growth factor receptor, and folate receptor. 
     
     
         12 . The conjugate of  claim 11 , wherein the tumor cells are selected from breast cancer cells, prostate cancer cells, ovarian cancer cells, colorectal cancer cells, gastric cancer cells, squamous cancer cells, small-cell lung cancer cells, and testicular cancer cells. 
     
     
         13 . A pharmaceutical composition comprising an effective amount of the drug-cell-binding agent conjugate of  claim 2 , a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutically acceptable carrier, diluent or excipient. 
     
     
         14 . A method for treating a disease sensitive to treatment with said method, said method comprising parenterally administering to a patient in need thereof an effective dose of the conjugate of  claim 2 . 
     
     
         15 . The method of  claim 14 , wherein said disease is selected from tumor, autoimmune diseases, graft rejections, graft versus host disease, viral infections, and parasite infections. 
     
     
         16 . The method of  claim 15 , wherein said tumor is selected from one or more of cancers of the lung, blood, plasma, breast, colon, prostate, kidney, pancreas, brain, bones, ovary, testes, and lymphatic organs. 
     
     
         17 . The method of  claim 15 , wherein said tumor expresses one or more of IGF-IR, FOLR1, CanAg, EGFR, EphA2, MUC1, MUC16, VEGF, TF, MY9, anti-B4, EpCAM, CD2, CD3, CD4, CD5, CD6, CD11, CD11a, CD18, CD19, CD20, CD22, CD26, CD30, CD33, CD37, CD38, CD40, CD44, CD56, CD70, CD79, CD105, CD138, EphA, EphB, EGFRvIII, HER2/neu, HER3, mesothelin, cripto, alpha v beta 3 integrin, alpha v beta 5 integrin, alpha v beta 6  integrin, Apo2, and C242 antigens. 
     
     
         18 - 33 . (canceled)