Prodruggable antibodies, prodrugs thereof, and methods of use and making
A prodrugged antibody has a blocking moiety attached to a Cys on its heavy or light chain via a linker having a cleavable moiety. The blocking moiety inhibits binding of the antibody to its antigen. Cleavage of the cleavable moiety releases the blocking moiety and restores ability of the antibody to bind to its antigen.
1. A prodrugged antibody according to formula (I)
(BM-L) m -Ab (I)
wherein
Ab is an antibody having at least one amino acid in its heavy or light chain variable region replaced by a Cys, wherein the replaced amino acid (a) is in a framework region; (b) has a side chain exposure of at least 30% and (c) is within 10 Å, of a CDR amino acid;
BM is a blocking moiety that inhibits binding of Ab to its antigen;
each L is, independently, a linker moiety bonded to BM and Ab, L comprising a cleavable moiety and being bonded to Ab at aforesaid Cys; and
m is 1, 2, 3, or 4; and
wherein blocking moiety BM is a poly(ethylene glycol).
2. The prodrugged antibody of claim 1 , wherein the at least one replaced amino acid in antibody Ab is at Kabat position 1, 3, 5, 19, 23, 25, 43, 46, 68, 72, 74, 75, 76, 82a, 82b, 83, 84, 85, or 105 of the heavy chain variable region or at Kabat position 1, 3, 5, 7, 8, 18, 20, 45, 57, 60, 63, 65, 66, 67, 69, 77, or 100 of the light chain variable region.
3. The prodrugged antibody of claim 1 , wherein the at least one replaced amino acid in antibody Ab is at Kabat position 23 of the heavy chain or Kabat position 67 of the light chain.
4. The prodrugged antibody of claim 1 , wherein the at least one replaced amino acid in antibody Ab is at Kabat position 23 of the heavy chain.
5. The prodrugged antibody of claim 1 , wherein the at least one replaced amino acid in antibody Ab is Kabat position 67 of the light chain.
6. The prodrugged antibody of claim 1 , wherein the poly(ethylene glycol) has a molecular weight of at least about 2 kDa.
7. The prodrugged antibody of claim 1 , wherein cleavable moiety in L is an enzymatically cleavable peptide.
8. The prodrugged antibody of claim 7 , wherein the enzymatically cleavable peptide is cleavable by at least one enzyme selected from the group consisting of fibroblast activation protein (FAP), urokinase-type plasminogen activator (uPA, urokinase), MT-SP1/matriptase, legumain, and a matrix metalloprotease.
9. The prodrugged antibody of claim 8 , wherein the enzyme is matriptase.
10. The prodrugged antibody of claim 7 , wherein the enzymatically cleavable peptide is LSGRSDNH (SEQ ID NO:5), LSGX (SEQ ID NO:16) or LSGK (SEQ ID NO:16).
11. The prodrugged antibody of claim 1 , having a structure according to formula (IIa) to (IIh):