Smart Pro-Drugs of Serine Protease Inhibitors
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.