2532 Background: Pertuzumab, a humanized HER2-targeted antibody, represents the first in a new class of targeted therapeutic agents known as HER2 dimerization inhibitors (HDIs). Pertuzumab blocks ligand-associated HER2 dimerization with HER kinase family members (EGFR, HER3, HER4), thereby inhibiting intracellular signaling through MAP and PI3 kinases. Pertuzumab is currently being evaluated in phase II studies as a single-agent in ovarian, breast, prostate, and lung cancers. Interim pertuzumab PK data from the phase II studies is presented. Methods: Pertuzumab was administered once every 3 weeks (q3 week) as an IV infusion at a fixed dose of either 420 mg following an initial 840 mg loading dose (LD), or 1050 mg with no LD. PK data from four phase II studies were pooled for analysis by both descriptive and population PK (PopPK) modeling Methods: Results: PopPK modeling of the data from ovarian and breast cancer studies showed that a linear 2-compartment model best described the concentration-time profile...