Smart Pro-Drugs of Serine Protease Inhibitors

Abstract

The present invention relates to prodrugs of protease inhibitors, such as inhibitors of the proteosome, DPP IV, FAPα and the like. These “pro-inhibitors” are activated, i.e., cleaved, by an “activated protease” to release an active inhibitor moiety in proximity to a “target protease”. The identity of activating protease and target protease can be the same (such as pro-inhibitors being referred to as “Target-Activated Smart Protease Inhibitors” or “TASPI”) or different (e.g., “Target-Directed Smart Protease Inhibitors” or “TDSPI”). After activation of the pro-inhibitor, the active inhibitor moiety can self-inactivate by, e.g., intramolecular-cyclization or cis-trans isomerization.

1 - 28 . (canceled) 
     
     
         29 . A prodrug represented by formula (I) or a solvate, pharmaceutically functional derivative or pharmaceutically acceptable salt thereof:
   A-G  (I)   
       wherein
 A represents a peptidyl moiety, 2-10 amino acid residues in length, that is a substrate for an activating protease which is associated with tumors; A and G are covalently linked by a bond that is cleaved by the activating protease; and 
 G represents a dipeptidyl proteosome inhibitor moiety that, when released from the prodrug by cleavage by the activating protease, inhibits the proteolytic activity of a proteosome with a Ki of 100 nM or less, 
 
       wherein, the dipeptidyl proteosome inhibitor moiety G, when cleaved from A by the activating protease, undergoes reversible cyclization-dependent inactivation over time. 
     
     
         30 . The prodrug of  claim 29 , wherein A is a dipeptidyl or tripeptidyl moiety. 
     
     
         31 . The prodrug of  claim 29 , wherein at least one residue of A is a non-naturally occurring amino acid analog. 
     
     
         32 . The prodrug of  claim 29 , wherein at least one residue of A is a D-amino acid. 
     
     
         33 . The prodrug of  claim 29 , wherein the amino terminus of A is blocked with an amino-terminal protecting group. 
     
     
         34 . The prodrug of  claim 33 , wherein the amino-terminal protecting group is an acyl group. 
     
     
         35 . The prodrug of  claim 34 , wherein the acyl group is selected from the group consisting of formyl, dansyl, acetyl, benzoyl, trifluoroacetyl, succinyl and methoxysuccinyl. 
     
     
         36 . The prodrug of  claim 29 , wherein the dipeptidyl proteosome inhibitor moiety G is represented by formula (II):
   Xaa 1 -Xaa 2 -W  (II)   wherein
 Xaa 1  and Xaa 2  each independently represent an amino acid residue; 
 W represents —CN, —CH═NR 5 , 
   
       
         
           
           
               
               
           
         
         
           R 5  represents H, an alkyl, an alkenyl, an alkynyl, —C(X 1 )(X 2 )X 3 , —(CH 2 )m-R 6 , —(CH 2 )n-OH, —(CH 2 )n-O-alkyl, —(CH 2 )n-O-alkenyl, —(CH 2 )n-O-alkynyl, —(CH 2 )n-O—(CH 2 )m-R 6 , —(CH 2 )n-SH, —(CH 2 )n-S-alkyl, —(CH 2 )n-S-alkenyl, —(CH 2 )n-S-alkynyl, —(CH 2 )n-S—(CH 2 ) m —R 6 , —C(O)C(O)NH 2 , —C(O)C(O)OR 7 ; 
           R 6  represents, independently for each occurrence, a substituted or unsubstituted aryl, aralkyl, cycloalkyl, cycloalkenyl, or heterocycle; 
           R 7  represents, independently for each occurrence, hydrogen, or a substituted or unsubstituted alkyl, alkenyl, aryl, aralkyl, cycloalkyl, cycloalkenyl, or heterocycle; 
           Y 1  and Y 2  can independently or together be OH, or a group capable of being hydrolyzed to a hydroxyl group, including cyclic derivatives where Y 1  and Y 2  are connected via a ring having from 5 to 8 atoms in the ring structure; 
           R 50  represents O or S; 
           R 51  represents N 3 , SH 2 , NH 2 , NO 2  or —OR 7 ; 
           R 52  represents hydrogen, a lower alkyl, an amine, —OR 7 , or a pharmaceutically acceptable salt, or R 51  and R 52  taken together with the phosphorous atom to which they are attached complete a heterocyclic ring having from 5 to 8 atoms in the ring structure; 
           X 1  represents a halogen; 
           X 2  and X 3  each represent a hydrogen or a halogen; 
           m is zero or an integer in the range of 1 to 8; and n is an integer in the range of 1 to 8. 
         
       
     
     
         37 . The prodrug of  claim 36 , wherein W is 
       
         
           
           
               
               
           
         
       
       and Y 1  and Y 2  are OH. 
     
     
         38 . The prodrug of  claim 36 , wherein Xaa 1  or Xaa 2  is a non-naturally occurring amino acid analog. 
     
     
         39 . The prodrug of  claim 29 , wherein the activating protease is Fibroblast Activating Protein (FAP), Prostate Specific Antigen (PSA), Dipeptidylpeptidase IV (DPIV), matriptase or falcipain. 
     
     
         40 . The prodrug of  claim 39 , wherein the activating protease is Fibroblast Activating Protein (FAP). 
     
     
         41 . The prodrug of  claim 29 , wherein the reversible cyclization-dependent inactivation comprises the dipeptidyl proteosome inhibitor moiety G undergoing inter-conversion between linear and cyclic forms, wherein the cyclic form has a Ki for inhibiting the proteosome at least 2 times greater than the linear form. 
     
     
         42 . The prodrug  claim 29 , wherein the cyclic form has a Ki at least 10 times the Ki of the linear form. 
     
     
         43 . The prodrug of  claim 29 , wherein the cyclic form has a Ki at least 100 times the Ki of the linear form. 
     
     
         44 . The prodrug of  claim 29 , wherein the prodrug has a therapeutic index at least two times greater than the therapeutic index for the dipeptidyl proteosome inhibitor moiety G when administered alone. 
     
     
         45 . A pharmaceutical composition, comprising a pharmaceutically acceptable carrier; and a prodrug of  claim 29 , or a pharmaceutically acceptable salt thereof. 
     
     
         46 . A packaged pharmaceutical, comprising one or more prodrugs of  claim 29  formulated in a pharmaceutically acceptable excipient, in association with instructions (written and/or pictorial) describing the recommended dosage and/or administration of the formulation to a patient.