Antibodies against the ectodomain of erbb3 and uses thereof

A method of treating a cancer in a patient, the method comprising co-administering to the patient, 1) a composition comprising a first agent that is an anti-ErbB3 antibody and 2) a second agent that is an anti-cancer agent other than the first agent, wherein:

• (a). the antibody comprises heavy chain variable region CDR1, CDR2, and CDR3 amino acid sequences as set forth in SEQ ID NOs:
• 7, 8, and 9, respectively, and light chain variable region CDR1, CDR2, and CDR3 amino acid sequences as set forth in SEQ ID NOs:
• 10, 11, and 12, respectively, and
• (b). the anti-cancer agent is selected from the group consisting of erlotinib, paclitaxel, and cisplatin.

A method of treating a cancer in a subject comprising administering to the subject the antibody, or antigen binding portion thereof, wherein the anti-ErbB3 antibody comprises SEQ ID NO:1, or an amino acid sequence at least 90% identical thereto, and a light chain variable region comprising SEQ ID NO:2, or an amino acid sequence at least 90% identical thereto, wherein the antibody binds the ectodomain of human ErbB3, and wherein the antibody comprises:

• (a) variable heavy chain residues Tyr32 or Phe32, Va133, Trp57, Met102, Thr104, and Ile105 of SEQ ID NO:
• 1;
• and
• (b) variable light chain residues Asp28, Tyr32 or Phe32, and Tyr93 or Phe93 of SEQ ID NO:
• 2.