<p>Pertuzumab is a humanized monoclonal antibody designed to bind to the HER2 receptor and inhibit the ability of HER2 to interact with other HER family members (HER1, HER2, HER3, and HER4) on the surface of cancer cells. The HER signaling pathway plays a role in the formation and growth of numerous cancers, and previous clinical trials of pertuzumab in a single agent setting had suggested clinical activity-including stable disease-in heavily pretreated patients with advanced ovarian and breast cancers.</p>