Napi2b-targeted antibody-drug conjugates and methods of use thereof

Abstract

This disclosure provides NaPi2b-targeted antibody-drug conjugates (e.g., NaPi2b-targeted antibody-polymer-drug conjugates) that specifically bind to the extracellular region of SLC34A2, and to methods of using such conjugates in a variety of therapeutic, diagnostic, and prophylactic indications.

1 . A conjugate comprising an isolated antibody that specifically binds to the extracellular region of SLC34A2 and one or more D-carrying polymeric scaffolds connected to the isolated antibody, wherein each of the one or more D-carrying polymeric scaffolds independently is of Formula (Ic): 
       
         
           
           
               
               
           
         
       
       wherein:
 the scaffold comprises poly(1-hydroxymethylethylene hydroxymethyl-formal) (PHF) having a molecular weight ranging from about 2 kDa to about 40 kDa; 
 each occurrence of D is independently a therapeutic agent having a molecular weight of ≤5 kDa; 
 L D1  is a carbonyl-containing moiety; 
 each occurrence of 
 
       
         
           
           
               
               
           
         
       
       is independently a first linker that contains a biodegradable bond so that when the bond is broken, D is released in an active form for its intended therapeutic effect; and the 
       
         
           
           
               
               
           
         
       
       between L D1  and D denotes direct or indirect attachment of D to L D1 ;
 each occurrence of 
 
       
         
           
           
               
               
           
         
       
       is independently a second linker not yet connected to the isolated antibody, in which L P2  is a moiety containing a functional group that is yet to form a covalent bond with a functional group of the isolated antibody, and the 
       
         
           
           
               
               
           
         
       
       between L D1  and L P2  denotes direct or indirect attachment of L P2  to L D1 , and each occurrence of the second linker is distinct from each occurrence of the first linker;
 each occurrence of 
 
       
         
           
           
               
               
           
         
       
       is independently a third linker that connects each D-carrying polymeric scaffold to the isolated antibody, in which the terminal 
       
         
           
           
               
               
           
         
       
       attached to L P2  denotes direct or indirect attachment of L P2  to the isolated antibody upon formation of a covalent bond between a functional group of L P2  and a functional group of the isolated antibody; and each occurrence of the third linker is distinct from each occurrence of the first linker;
 m is an integer from 1 to about 300, 
 m 1  is an integer from 1 to about 140, 
 m 2  is an integer from 1 to about 40, 
 m 3  is an integer from 0 to about 18, 
 m 4  is an integer from 1 to about 10; 
 the sum of m, m 1 , m 2 , m 3 , and m 4  ranges from 15 to 300; and 
 the total number of L P2  connected to the isolated antibody is 10 or less. 
 
     
     
         2 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 comprises a variable heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence GYTFTGYNIH (SEQ ID NO: 5), a variable heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence AIYPGNGDTSYKQKFRG (SEQ ID NO: 6), a variable heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence GETARATFAY (SEQ ID NO: 7), a variable light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence SASQDIGNFLN (SEQ ID NO: 8), a variable light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence YTSSLYS (SEQ ID NO: 9), a variable light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence QQYSKLPLT (SEQ ID NO: 10). 
     
     
         3 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 comprises a heavy chain variable sequence comprising the amino acid sequence of SEQ ID NO: 3 or an amino acid sequence at least 90% identical thereto and a light chain variable sequence comprising the amino acid sequence of SEQ ID NO: 4 or an amino acid sequence at least 90% identical thereto. 
     
     
         4 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 comprises a heavy chain comprising the amino acid sequence of SEQ ID NO: 1 or an amino acid sequence at least 90% identical thereto and a light chain comprising the amino acid sequence of SEQ ID NO: 2 or an amino acid sequence at least 90% identical thereto. 
     
     
         5 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 is a monoclonal antibody. 
     
     
         6 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 is a rabbit, mouse, chimeric, humanized or fully human monoclonal antibody. 
     
     
         7 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 is an IgG isotype. 
     
     
         8 . The conjugate of  claim 1 , wherein the isolated antibody that specifically binds the extracellular region of SLC34A2 is an IgG1 isotype. 
     
     
         9 . The conjugate of  claim 1 , wherein the isolated antibody (i) competes for specific binding to human NaPi2b with an isolated antibody comprising a variable heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence GYTFTGYNIH (SEQ ID NO: 5), a variable heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence AIYPGNGDTSYKQKFRG (SEQ ID NO: 6), a variable heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence GETARATFAY (SEQ ID NO: 7), a variable light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence SASQDIGNFLN (SEQ ID NO: 8), a variable light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence YTSSLYS (SEQ ID NO: 9), a variable light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence QQYSKLPLT (SEQ ID NO: 10), or (ii) competes for specific binding to human NaPi2b with an isolated antibody comprising a heavy chain variable sequence comprising the amino acid sequence of SEQ ID NO: 3 or an amino acid sequence at least 90% identical thereto and a light chain variable sequence comprising the amino acid sequence of SEQ ID NO: 4 or an amino acid sequence at least 90% identical thereto, or with an isolated antibody comprising a heavy chain comprising the amino acid sequence of SEQ ID NO: 1 or an amino acid sequence at least 90% identical thereto and a light chain comprising the amino acid sequence of SEQ ID NO: 2 or an amino acid sequence at least 90% identical thereto. 
     
     
         10 . (canceled) 
     
     
         11 . The conjugate of  claim 1 , wherein the sum of m, m 1 , m 2 , m 3  and m 4  ranges from 15 to 150, m 1  is an integer from 1 to 70, m 2  is an integer from 1 to 20, m 3  is an integer from 0 to 10, and PHF has a molecular weight ranging from about 2 kDa to about 20 kDa. 
     
     
         12 . The conjugate of  claim 1 , wherein the sum of m, m 1 , m 2 , m 3  and m 4  ranges from 20 to 110, m 1  is an integer from 2 to 50, m 2  is an integer from 2 to 15, m 3  is an integer from 0 to 8; and PHF has a molecular weight ranging from about 3 kDa to about 15 kDa. 
     
     
         13 . The conjugate of  claim 1 , wherein the sum of m, m 1 , m 2 , m 3  and m 4  ranges from 40 to 75, m 1  is an integer from 2 to 35, m 2  is an integer from 2 to 10, m 3  is an integer from 0 to 5; and PHF has a molecular weight ranging from about 5 kDa to about 10 kDa. 
     
     
         14 . The conjugate of  claim 1 , wherein the functional group of L P2  is selected from —SR p , —S—S-LG, 
       
         
           
           
               
               
           
         
       
       and halo, in which LG is a leaving group, R p  is H or a sulfur protecting group, and one of X a  and X b  is H and the other is a water-soluble maleimido blocking moiety, or X a  and X b , together with the carbon atoms to which they are attached for a carbon-carbon double bond. 
     
     
         15 . The conjugate of  claim 1 , wherein L D1  comprises —X—(CH 2 ) v —C(═O)— with X directly connected to the carbonyl group of 
       
         
           
           
               
               
           
         
       
       in which X is CH 2 , O, or NH, and v is an integer from 1 to 6. 
     
     
         16 . The conjugate of  claim 1 , wherein each occurrence of 
       
         
           
           
               
               
           
         
       
       is independently —C(═O)—X—(CH 2 ) v —C(═O)—NH—(CH 2 ) u —NHC(═O)—(CH 2 ) w —(OCH 2 CH 2 ) x —NHC(═O)—(CH 2 ) y -M, in which X is CH 2 , O, or NH, each of v, u, w, x and y independently is an integer from 1 to 6, and M is 
       
         
           
           
               
               
           
         
       
       wherein one of X a  and X b  is H and the other is a water-soluble maleimido blocking moiety, or X a  and X b , together with the carbon atoms to which they are attached for a carbon-carbon double bond. 
     
     
         17 . The conjugate of  claim 16 , wherein each of v, u, w, x and y is 2. 
     
     
         18 . The conjugate of  claim 1 , wherein each occurrence of D independently is selected from  vinca  alkaloids, auristatins, tubulysins, duocarmycins, calicheamicins, topoisomerase I inhibitors, PI3 kinase inhibitors, MEK inhibitors, KSP inhibitors, pyrrolobenzodiazepines, non-natural camptothecins, maytansinoids, DNA-binding drugs, DNA-alkylating drugs, RNA polymerase inhibitors, and analogs thereof. 
     
     
         19 . The conjugate of  claim 1 , wherein each of the one or more D-carrying polymeric scaffolds independently is of Formula (Id): 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       wherein:
 m 3a  is an integer from 0 to about 17, 
 m 3b  is an integer from 1 to about 8, and 
 
       the terminal 
       
         
           
           
               
               
           
         
       
       denotes the direct attachment of the one or more polymeric scaffolds to the isolated antibody. 
     
     
         20 . The conjugate of  claim 1 , wherein each of the one or more D-carrying polymeric scaffolds independently is of Formula (If): 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         wherein:
 m is an integer from 1 to about 300, 
 m 1  is an integer from 1 to about 140, 
 m 2  is an integer from 1 to about 40, 
 m 3a  is an integer from 0 to about 17, 
 m 3b  is an integer from 1 to about 8; 
 the sum of m 3a  and m 3b  ranges from 1 and about 18; and 
 the sum of m, m 1 , m 2 , m 3a , and m 3b  ranges from 15 to about 300; 
 the terminal 
 
       
       
         
           
           
               
               
           
         
       
       denotes the attachment of one or more polymeric scaffolds to the isolated antibody that specifically binds to SLC34A2, wherein the isolated antibody that specifically binds to SLC34A2 is an isolated antibody that comprises a variable light chain complementarity determining region 1 (CDRL1) comprising the amino acid sequence SASQDIGNFLN (SEQ ID NO: 8); a variable light chain complementarity determining region 2 (CDRL2) comprising the amino acid sequence YTSSLYS (SEQ ID NO: 9); a variable light chain complementarity determining region 3 (CDRL3) comprising the amino acid sequence QQYSKLPLT (SEQ ID NO: 10); a variable heavy chain complementarity determining region 1 (CDRH1) comprising the amino acid sequence GYTFTGYNIH (SEQ ID NO: 5); a variable heavy chain complementarity determining region 2 (CDRH2) comprising the amino acid sequence AIYPGNGDTSYKQKFRG (SEQ ID NO: 6); and a variable heavy chain complementarity determining region 3 (CDRH3) comprising the amino acid sequence GETARATFAY (SEQ ID NO: 7); and 
       the ratio between the PHF and the antibody is 10 or less. 
     
     
         21 . The conjugate of  claim 20 , wherein the PHF in Formula (If) has a molecular weight ranging from about 2 kDa to about 20 kDa, the sum of m, m 1 , m 2 , m 3a  and m 3b  ranges from about 15 to about 150, m 1  is an integer from 1 to about 70, m 2  is an integer from 1 to about 20, m 3a  is an integer from 0 to about 9, m 3b  is an integer from 1 to about 8, the sum of m 3a  and m 3b  ranges from 1 and about 10, and the ratio between the PHF and the isolated antibody that specifically binds to SLC34A2 is an integer from 2 to about 8. 
     
     
         22 . The conjugate of  claim 20 , wherein the PHF in Formula (If) has a molecular weight ranging from about 3 kDa to about 15 kDa, the sum of m, m 1 , m 2 , m 3a  and m 3b  ranges from about 20 to about 110, m 1  is an integer from 2 to about 50, m 2  is an integer from 2 to about 15, m 3a  is an integer from 0 to about 7, m 3b  is an integer from 1 to about 8, the sum of m 3a  and m 3b  ranges from 1 and about 8, and the ratio between the PHF and the isolated antibody that specifically binds to SLC34A2 is an integer from 2 to about 8. 
     
     
         23 . The conjugate of  claim 20 , wherein the PHF in Formula (If) has a molecular weight ranging from about 5 kDa to about 10 kDa, the sum of m, m 1 , m 2 , m 3a  and m 3b  ranges from about 40 to about 75, m 1  is an integer from about 2 to about 35, m 2  is an integer from about 2 to about 10, m 3a  is an integer from 0 to about 4, m 3b  is an integer from 1 to about 5, the sum of m 3a  and m 3b  ranges from 1 and about 5, and the ratio between the PHF and the isolated anti-antibody that specifically binds to SLC34A2 is an integer from 2 to about 8. 
     
     
         24 . The conjugate of  claim 20 , wherein the PHF in Formula (If) has a molecular weight ranging from about 5 kDa to about 10 kDa, the sum of m, m 1 , m 2 , m 3a  and m 3b  ranges from about 40 to about 75, m 1  is an integer from about 2 to about 35, m 2  is an integer from about 2 to about 10, m 3a  is an integer from 0 to about 4, m 3b  is an integer from 1 to about 5, the sum of m 3a  and m 3b  ranges from 1 and about 5, and the ratio between the PHF and the isolated antibody that specifically binds to SLC34A2 is an integer from 2 to about 6. 
     
     
         25 . A pharmaceutical composition comprising a conjugate of  claim 20  and a pharmaceutically acceptable carrier. 
     
     
         26 . A method of preparing a conjugate according to  claim 1 , comprising reacting an isolated antibody that specifically binds to SLC34A2 with a D-carrying polymeric scaffold of Formula (Ia) such that the conjugate is formed: 
       
         
           
           
               
               
           
         
         wherein: 
         L D1  is a carbonyl-containing moiety; 
         each occurrence of 
       
       
         
           
           
               
               
           
         
       
       is independently a first linker that contains a biodegradable bond so that when the bond is broken, D is released in an active form for its intended therapeutic effect; and the 
       
         
           
           
               
               
           
         
       
       between L D1  and D denotes direct or indirect attachment of D to L D1 ;
 each occurrence of 
 
       
         
           
           
               
               
           
         
       
       is independently a second linker not yet connected to the isolated antibody, in which L 2  is a moiety containing a functional group that is yet to form a covalent bond with a functional group of the isolated antibody, and the 
       
         
           
           
               
               
           
         
       
       between L D1  and L P2  denotes direct or indirect attachment of L P2  to L D1 , and each occurrence of the second linker is distinct from each occurrence of the first linker;
 m is an integer from 1 to about 300, 
 m 1  is an integer from 1 to about 140, 
 m 2  is an integer from 1 to about 40, 
 m 3  is an integer from 1 to about 18, and 
 the sum of m, m 1 , m 2  and m 3  ranges from 15 to about 300. 
 
     
     
         27 . A method of alleviating a symptom of a cancer in a subject in need thereof, the method comprising administering a conjugate according to  claim 20  to the subject in an amount sufficient to alleviate the symptom of the cancer. 
     
     
         28 . The method of  claim 27 , wherein the subject is human. 
     
     
         29 . The method of  claim 27 , wherein the cancer is selected from the group consisting of ovarian cancer, thyroid cancer, colorectal cancer, lung cancer, non-small cell lung cancer (NSCLC), breast cancer, kidney cancer and salivary duct carcinoma. 
     
     
         30 . The method of  claim 27 , wherein the cancer is selected from the group consisting of non-small cell lung cancer (NSCLC) and ovarian cancer. 
     
     
         31 . The method of  claim 30 , wherein the non-small cell lung cancer is non-squamous non-small cell lung cancer. 
     
     
         32 . The method of  claim 30 , wherein the ovarian cancer is epithelial ovarian cancer. 
     
     
         33 . The method of  claim 27 , further comprising administration of a therapeutic agent to the subject. 
     
     
         34 . The method of  claim 27 , wherein the subject has one or more ovarian cancers selected from recurrent ovarian cancer, platinum-sensitive ovarian cancer, platinum-refractory ovarian cancer, and platinum-resistant ovarian cancer; or the subject has advanced ovarian cancer and has not received any prior chemotherapy for treating cancer. 
     
     
         35 . (canceled)