NZ 602621 Disclosed is an antibody, or fragment thereof, that specifically binds human CSF-1R variant, comprising a CDRH1 comprising the sequence SYGMH (SEQ ID NO: 1), a CDRH2 comprising the sequence VIWYDGSNKYYADSVKG (SEQ ID NO: 2), a CDRH3 comprising the sequence GDYEVDYGMDV (SEQ ID NO: 3), a CDRL1 comprising the sequence RASQGISNALA (SEQ ID NO: 4), a CDRL2 comprising the sequence DASSLES (SEQ ID NO: 5), and a CDRL3 comprising the sequence QQFNSYPWT (SEQ ID NO: 6). Also disclosed is a method for determining whether a subject having a cancer is a candidate for an anti-CSF-1R antibody-based cancer treatment regimen with the antibody defined in the specification. The method comprises determining the level of CSF-1, or IL-34, or both, in a sample of the subject, wherein an increase in the level of CSF-1, or IL-34, or both, as compared with the level of CSF-1, or IL-34, or both, in an individual not suffering from cancer, is indicative that the subject is a candidate for the anti-CSF-1R antibody-based cancer treatment regimen.
