An antibody specific to human FMS-Like tyrosine kinase 3 receptor (FLT3)

Abstract

The present invention provides a fully human antibody that specifically binds to human FLT3 within extracellular domains 4 or 5 with high affinity. In particular disclosed is an antibody that specifically binds human FLT3 (SEQ ID NO. 43), comprising a CDRH1 having the sequence SYYMH (SEQ ID NO:2), a CDRH2 having the sequence IINPSGGSTSYAQKFQG (SEQ ID NO:3), a CDRH3 having the sequence GVGAHDAFDI (SEQ ID NO:4) or VVAAAVADY (SEQ ID NO:5), a CDRL1 having the sequence RSSQSLLHSNGNNYLD (SEQ ID NO:6) or RSSQSLLHSNGYNYLD (SEQ ID NO:7), a CDRL2 having the sequence LGSNRAS (SEQ ID NO:8), and a CDRL3 having the sequence MQGTHPAIS (SEQ ID NO:9) or MQSLQTPFT (SEQ II) NO: 11). The invention further provides a pharmaceutical composition for treating leukemia by administering an effective amount of an antibody either alone or in combination with an anti-cancer agent or treatment including methotrexate.