Panning for Omnitarg activity
The development of Omnitarg pertuzumab - the other anti-HER-2/neu antibody from Genentech Inc. - hit a snag last week when DNA disclosed that Phase II results for the compound as monotherapy in patients with ovarian cancer did not warrant a Phase III trial in that setting. Yet the company still has hope for the compound because of its activity as a pan-inhibitor of HER family signaling. This potentially could position pertuzumab as an anti-HER-2 antibody with broader activity than Herceptin.
Except in the comple-mentarity-determining regions of the antibodies, the protein sequence of pertu-zumab is identical to that of Herceptin trastuzumab, which DNA (South San Francisco, Calif.) and Roche (SWX:ROCZ, Basel, Switzerland) market to treat patients with metastatic breast cancer whose tumors overexpress HER-2. However, the two antibodies bind to different regions of the extracellular portion of HER-2 and behave differently biologically. ...