Detecting human anti-therapeutic antibodies

1 . A method of detecting human anti-therapeutic antibodies in a sample from a patient, the method comprising the steps of:

providing a first therapeutic antibody having a molecular tag attached thereto by a cleavable linkage, the molecular tag having one or more predetermined separation characteristics;

providing a second therapeutic antibody having a cleavage-inducing moiety attached thereto, the cleavage-inducing moiety having an effective proximity;

combining in an assay mixture the sample, the first therapeutic antibody, and the second therapeutic antibody under condition such that the first and second therapeutic antibodies form a complex with an anti-therapeutic antibody wherein the cleavable linkage of the first therapeutic antibody is within the effective proximity of the cleavage-inducing moiety of the second therapeutic antibody and molecular tags are released; and

separating from the assay mixture and detecting the released molecular tags to determine the presence or absence of anti-therapeutic antibodies in the sample.

2 . The method of claim 1 wherein said step of combining includes generating an active species by said cleavage-inducing moiety, the active species cleaving said cleavable linkages within said effective proximity.

3 . The method of claim 2 wherein said cleavage-inducing moiety is a photosensitizer and said active species is singlet oxygen.

4 . The method of claim 2 wherein said predetermined separation characteristic is electrophoretic mobility.

5 . A method of detecting human anti-therapeutic antibodies in a sample from a patient, the method comprising the steps of:

providing a first therapeutic antibody having a molecular tag attached thereto by a cleavable linkage, the molecular tag having one or more predetermined separation characteristics;

providing a second therapeutic antibody having a capture moiety;

combining in an assay mixture the sample, the first therapeutic antibody, and the second therapeutic antibody under condition such that the first and second therapeutic antibodies form a complex with an anti-therapeutic antibody;

separating the complex from unbound first therapeutic antibody by capturing the complex with a capture agent the specifically binds to the capture moiety, the capture agent being attached to a solid phase support;

cleaving the cleavable linkages of first therapeutic antibody of the complex to release molecular tags; and

separating and detecting the released molecular tags to determine the presence or absence of anti-therapeutic antibodies in the sample.

6 . The method of claim 5 wherein said predetermined separation characteristic is electrophoretic mobility.

7 . The method of claim 5 wherein said capture moiety is biotin and said capture agent is avidin or streptavidin.

8 . The method of claim 5 wherein said first therapeutic antibody and said second therapeutic antibody are each selected from the group consisting of anti-EGFR antibodies, anti-Her2 antibodies, anti-Her3 antibodies, anti-IGF-IR antibodies, anti-VEGFR antibodies, anti-TRAIL receptor-1 antibodies, and anti-FGF receptor antibodies.

9 . The method of claim 5 wherein said first therapeutic antibody and said second therapeutic antibody are each selected from the group consisting of vitaxin, herceptin, semaxanib, erbitux, cantuzumab, rituximab, panitumomab, alemtuzumab, eculizumab, HuMax-CD4, brevarex, oregovomab, pemtumomab, pertuzumab, and ovarex.

10 . The method of claim 5 wherein said first therapeutic antibody and said second therapeutic antibody are each pathway-specific drugs.

11 . The method of claim 5 wherein said first therapeutic antibody and said second therapeutic antibody are each specific for a receptor tyrosine kinase.