Fap-activated serum extended half-life therapeutic conjugates

A therapeutic conjugate comprising a therapeutic moiety linked through a fibroblast activation protein, alpha (FAPα)-cleavable linker to a half-life extension moiety, wherein the circulating serum half-life of the therapeutic conjugate in vivo is extended by more than 2-fold relative to circulating serum half-life of a free therapeutic moiety, and the conjugate does not comprise a cell-binding moiety that binds to a cell surface protein of a cell with a Kd of 1×10−6 M or less.

The therapeutic conjugate of any one of the preceding claims comprising:

The therapeutic conjugate of any one of the preceding claims, wherein the FAPα-cleavable linker is an oligopeptide.

The therapeutic conjugate of any one of the preceding claims, wherein the substrate recognition sequence of the FAPα-cleavable linker comprises a third amino position, optionally N-terminal to (d)-Ala, and optionally wherein the amino acid at the third amino acid position is serine or threonine.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is a cytotoxic agent.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is a cytostatic agent.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is an epigenetic agent.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety induces an innate immune response in vivo.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is acutely toxic.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is selected from TLR agonists, RIG-I agonists, iDASH inhibitors, and STING agonists.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is Val-boroPro (Talabostat).

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety comprises a receptor ligand.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is represented by

• —RBM—(Z)p
• wherein RBM is a receptor binding moiety, Z is cytotoxic, cytostatic or epigenetic moiety or a radioisotope containing moiety, and p is 0 (Z is absent) or an integer from 1 to 8.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety is represented by

• —RBM-L3-Z
• wherein RBM is a receptor binding moiety, Z is cytotoxic, cytostatic or epigenetic moiety or a radioisotope containing moiety, and L3 is a bond or a cleavable or non-cleavable linker.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety has a circulating serum half-life that it is at least 5, 10, 25, 50, 100 or even 1000 times longer than the circulating serum half-life of the free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic moiety has a circulating serum half-life that it is at least 10, 25, 50, 100, 200, or 300 hours.

The therapeutic conjugate of any one of the preceding claims, wherein for a period of at least 10, 24, 48, 72, 96, or 120 hours the therapeutic conjugate produces a concentration of free therapeutic moiety in target FAPα-expressing tissue that is at least 2, 5, 10, 20, 50, 75 or 100 times the concentration of free therapeutic moiety in systemic circulation over the same period of time.

The therapeutic conjugate of any one of the preceding claims, wherein when administered to a subject having an FAPα+ tumor, the therapeutic conjugate produces an intratumoral concentration of free therapeutic moiety that is at or above the EC50 for the antitumor activity of the free therapeutic moiety for a period at least 10, 24, 48, 72, 96, or 120 hours.

The therapeutic conjugate of any one of the preceding claims, wherein when administered to a subject having an FAPα+ tumor, the therapeutic conjugate has a therapeutic index for antitumor activity of at least 2, 5, 10, 25, 50, 100, or 500.

The therapeutic conjugate of any one of the preceding claims, wherein when administered to a subject having an FAPα+ tumor, the therapeutic conjugate has a therapeutic index for antitumor activity that is at least 2, 10, 50, 100, 250, 500, 1000, 5000, or 10,000 times greater than the therapeutic index of the free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein a greater percentage of free therapeutic moiety is localized in a target tissue expressing FAPα, relative to free therapeutic moiety, when compared on an equivalent dose basis, optionally wherein the ratio of free therapeutic moiety localized in the target tissue relative to other tissue (such as blood, liver or heart) is at least 2, 5, 10, 100, or 1000 times greater for an equivalent dose of the therapeutic conjugate relative to the free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein the maximum tolerated dose of the therapeutic conjugate is at least 2, 5, 10, 100, or 1000 times greater than the maximum tolerated dose of the free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein the cell permeability of the therapeutic conjugate is at least 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99%, or 99.9% less than the cell permeability of free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein the circulating half-life of the therapeutic conjugate is at least 25%, 50%, 75%, 100%, 150%, 200%, 500%, 750%, or 1000% longer than the circulating half-life of free therapeutic moiety.

The therapeutic conjugate of any one of the preceding claims, wherein the therapeutic conjugate has less than 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99%, 99.9%, or 99.99% of the cytotoxic or cytolytic activity against tumor cells relative to free therapeutic moiety.

A composition comprising the therapeutic conjugate of any one of the preceding claims and a pharmaceutically acceptable excipient.

A method comprising administering to a subject the therapeutic conjugate or composition of any one of the preceding claims, wherein the subject has a diseased tissue, optionally a cancer.

The therapeutic conjugate or composition of any one of the preceding claims for use in a method for treating a diseased tissue, optionally a cancer.

Use of the therapeutic conjugate of any one of the preceding claims in the manufacture of a medicament for the treatment of a diseased tissue, optionally a cancer.