Compositions and methods for the depletion of cd117+ cells

Abstract

The invention provides compositions and methods useful for the depletion of CD117+ cells and for the treatment of various hematopoietic diseases, metabolic disorders, cancers, and autoimmune diseases, among others. Described herein are antibodies, antigen-binding fragments, ligands, and conjugates thereof that can be applied to effect the treatment of these conditions, for instance, by depleting a population of CD117+ cells in a patient, such as a human. The compositions and methods described herein can be used to treat a disorder directly, for instance, by depleting a population of CD117+ cancer cells or autoimmune cells. The compositions and methods described herein can also be used to prepare a patient for hematopoietic stem cell transplant therapy and to improve the engraftment of hematopoietic stem cell transplants by selectively depleting endogenous hematopoietic stem cells prior to the transplant procedure.

1 .- 112 . (canceled) 
     
     
         113 . A method of depleting a population of CD117+ cells in a human patient in need of a hematopoietic stem cell transplant, the method comprising administering to the human patient in need of a hematopoietic stem cell transplant an effective amount of a conjugate comprising an anti-CD117 antibody and, wherein the anti-CD117 antibody comprises an Fc domain and is internalized by a CD117+ cell, wherein the anti-CD117 antibody is conjugated to the amatoxin via a linker by way of a cysteine residue in the Fc domain of the antibody, and wherein the amatoxin is represented by formula (I) 
       
         
           
           
               
               
           
         
         wherein R 1  is H, OH, OR A , or OR C ; 
         R 2  is H, OH, OR B , or OR C ; 
         R A  and R B , together with the oxygen atoms to which they are bound, combine to form an optionally substituted 5-membered heterocyclolalkyl group; 
         R 3  is H, R C , or R D ; 
         R 4 , R 5 , R 6 , and R 7  are each independently H, OH, OR C , OR D , R C , or R D ; 
         R 8  is OH, NH 2 , OR C , OR D , NHR C , or NR C R D ; 
         R 9  is H, OH, OR C , or OR D ; 
         X is —S—, —S(O)—, or —SO 2 —; 
         R C  is -L-Z; 
         R D  is substituted C 1 -C 6  alkyl, substituted C 1 -C 6  heteroalkyl, substituted C 2 -C 6  alkenyl, substituted C 2 -C 6  heteroalkenyl, substituted C 2 -C 6  alkynyl, substituted C 2 -C 6  heteroalkynyl, substituted cycloalkyl, substituted heterocycloalkyl, substituted aryl, or substituted heteroaryl; 
         L is a linker which is C 1 -C 6  alkylene, C 1 -C 6  heteroalkylene, C 2 -C 6  alkenylene, C 2 -C 6  heteroalkenylene, C 2 -C 6  alkynylene, C 2 -C 6  heteroalkynylene, or comprises a peptide; and 
         Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within the antibody, and 
         wherein the amatoxin comprises exactly one R C  substituent. 
       
     
     
         114 . The method of  claim 113 , wherein the antibody is an IgG. 
     
     
         115 . The method of  claim 113 , wherein the population of CD117+ cells comprises hematopoietic stem cells (HSCs). 
     
     
         116 . The method of  claim 113 , further comprising administering a transplant comprising hematopoietic stem cells to the human patient. 
     
     
         117 . The method of  claim 113 , wherein the patient has a hematological cancer. 
     
     
         118 . The method of  claim 117 , wherein the hematological cancer is selected from the group consisting of leukemia, lymphoma, multiple myeloma, and neuroblastoma. 
     
     
         119 . The method of  claim 113 , wherein R 5  is OR C . 
     
     
         120 . The method of  claim 113 , wherein R 8  is NHR C . 
     
     
         121 . The method of  claim 113 , wherein R 1  and R 2  are each OH. 
     
     
         122 . The method of  claim 113 , wherein L is a linker which is C 1 -C 6  alkylene, C 1 -C 6  heteroalkylene, C 2 -C 6  alkenylene, C 2 -C 6  heteroalkenylene, C 2 -C 6  alkynylene, or C 2 -C 6  heteroalkynylene. 
     
     
         123 . The method of  claim 113 , wherein L is a linker which comprises a peptide. 
     
     
         124 . The method of  claim 113 , wherein the cysteine residue is introduced by way of a mutation in the Fc domain of the antibody. 
     
     
         125 . The method of  claim 113 , wherein the cysteine residue is naturally occurring in the Fc domain of the antibody. 
     
     
         126 . The method of  claim 113 , wherein the hematopoietic stem cell transplant comprises allogeneic cells. 
     
     
         127 . The method of  claim 113 , wherein the hematopoietic stem cell transplant comprises autologous cells. 
     
     
         128 . The method of  claim 113 , wherein the human patient has a hemoglobinopathy disorder. 
     
     
         129 . The method of  claim 128 , wherein the hemoglobinopathy disorder is selected from the group consisting of sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, and Wiskott-Aldrich syndrome. 
     
     
         130 . The method of  claim 113 , wherein the human patient has an autoimmune disease. 
     
     
         131 . A method of treating a human patient having a stem cell disorder, the method comprising administering to the human patient having a stem cell disorder an effective amount of a conjugate comprising an anti-CD117 antibody and an amatoxin, wherein a population of endogenous CD117+ hematopoietic stem cells (CD117+ HSCs) is depleted following administration of the conjugate, wherein the anti-CD117 antibody comprises an Fc domain and is internalized by a CD117+ cell, wherein the anti-CD117 antibody is conjugated to the amatoxin by way of a cysteine residue in the Fc domain of the antibody, wherein the amatoxin is represented by formula (I) 
       
         
           
           
               
               
           
         
         wherein R 1  is H, OH, OR A , or OR C ; 
         R 2  is H, OH, OR B , or OR C ; 
         R A  and R B , together with the oxygen atoms to which they are bound, combine to form an optionally substituted 5-membered heterocyclolalkyl group; 
         R 3  is H, R C , or R D ; 
         R 4 , R 5 , R 6 , and R 7  are each independently H, OH, OR C , OR D , R C , or R D ; 
         R 8  is OH, NH 2 , OR C , OR D , NHR C , or NR C R D ; 
         R 9  is H, OH, OR C , or OR D ; 
         X is —S—, —S(O)—, or —SO 2 —; 
         R C  is -L-Z; 
         R D  is substituted C 1 -C 6  alkyl, substituted C 1 -C 6  heteroalkyl, substituted C 2 -C 6  alkenyl, substituted C 2 -C 6  heteroalkenyl, substituted C 2 -C 6  alkynyl, substituted C 2 -C 6  heteroalkynyl, substituted cycloalkyl, substituted heterocycloalkyl, substituted aryl, or substituted heteroaryl; 
         L is a linker which is C 1 -C 6  alkylene, C 1 -C 6  heteroalkylene, C 2 -C 6  alkenylene, C 2 -C 6  heteroalkenylene, C 2 -C 6  alkynylene, C 2 -C 6  heteroalkynylene, or comprises a peptide; and 
         Z is a chemical moiety formed from a coupling reaction between a reactive substituent present on L and a reactive substituent present within the antibody, and wherein the amatoxin comprises exactly one R C  substituent, 
         further comprising administering a transplant comprising hematopoietic stem cells to the human patient. 
       
     
     
         132 . The method of  claim 131 , wherein R 5  is OR C . 
     
     
         133 . The method of  claim 131 , wherein R 8  is NHR C . 
     
     
         134 . The method of  claim 131 , wherein R 1  and R 2  are each OH. 
     
     
         135 . The method of  claim 131 , wherein Lisa linker which is C 1 -C 6  alkylene, C 1 -C 6  heteroalkylene, C 2 -C 6  alkenylene, C 2 -C 6  heteroalkenylene, C 2 -C 6  alkynylene, or C 2 -C 6  heteroalkynylene. 
     
     
         136 . The method of  claim 131 , wherein L is a linker which comprises a peptide. 
     
     
         137 . The method of  claim 131 , wherein the stem cell disorder is a hematological cancer or an autoimmune disease. 
     
     
         138 . The method of  claim 137 , wherein the hematological cancer is selected from the group consisting of leukemia, lymphoma, multiple myeloma, and neuroblastoma. 
     
     
         139 . The method of  claim 131 , wherein the human patient has a hemoglobinopathy disorder. 
     
     
         140 . The method of  claim 136 , wherein the hemoglobinopathy disorder is selected from the group consisting of sickle cell anemia, thalassemia, Fanconi anemia, aplastic anemia, and Wiskott-Aldrich syndrome. 
     
     
         141 . The method of  claim 131 , wherein the transplant comprises autologous cells.