HER2-Positive Breast Cancer

PLANTATION, Florida-The humanized anti-HER2 antibody trastuzumab (Herceptin) produced an overall response rate of 26% when used as first-line therapy in women with metastatic breast cancer whose tumors overexpress HER2.

ROCKVILLE, Md-The FDA’s Hematology and Pathology Devices Panel voted unanimously to recommend that the agency grant conditional approval to Vysis, Inc.’s PathVysion HER-2 DNA Probe Kit to detect and quantify the HER2 gene in breast cancer patients. Based on Vysis’ fluorescence in situ hybridization (FISH) technology, the test for the HER2 gene was developed as a predictive marker for determining a patient’s response to doxorubicin-based chemotherapy.

COPENHAGEN, Denmark--Dako Corporation’s HercepTest was recommended unanimously for FDA approval by a joint committee of the Hematology and Pathology Devices Panel and Immunology Devices Panel, conditional on the company providing clear guidelines on how to conduct the test, so that laboratories can provide consistent results

LOS ANGELES--Tamoxifen (Nol-vadex) may not prevent breast cancer recurrence in women whose tumors over-express the HER2 oncogene (also known as c-erbB-2), and such overexpression may be a predictor of responsiveness to chemotherapy, researchers said at the ASCO integrated symposium on HER2 in breast cancer.

LOS ANGELES--Bioengineered antibodies against HER2 received major attention at the the 34th Annual Meeting of the American Society of Clinical Oncology, but other approaches to HER2-expressing tumors are waiting in the wings. One uses an antitumor peptide vaccine to induce specific T-cell immunity to HER2. Another uses anti-HER2 immunoliposomes to steer intracellular delivery of antitumor drugs.

LOS ANGELES--A monoclonal antibody directed at the HER2 receptor greatly enhances the effect of chemotherapy for women whose breast cancer overexpresses the HER2 gene. This encouraging finding comes as experts are beginning to suspect that increasing dose intensity of conventional chemotherapy may have "gone about as far as it can go," said Dennis Slamon, MD, PhD, chief, Division of Hematology-Oncology, UCLA School of Medicine.

Overexpression by the HER2 gene plays a significant role in breast cancer pathogenesis, and the phenomenon is commonly regarded as a predictor of a poor prognosis. HER2 overexpression has been linked to sensitivity and/or resistance to hormone therapy and chemotherapeutic regimens, including CMF (cyclophosphamide, methotrexate, and fluoro-uracil) and anthracyclines. Studies of patients with advanced disease demonstrate that, despite the association of HER2 overexpression with poor prognosis, the odds of HER2-positive patients responding clinically to taxanes were greater than three times those of HER2-negative patients. Further studies in preclinical models used combination therapy for breast cancer cells that overexpress HER2, and the use of agents that interfere with HER2 function plus paclitaxel (Taxol) resulted in significant antitumor effects. [ONCOLOGY 11(Suppl):43-48, 1997]

PARIS--Although properly applied high-dose chemotherapy can produce massive cytoreduction in breast cancer, it may not be adequate to cure the disease. "The problem has never been the achievement of remissions with high-dose therapy; the problem is making them stick," Larry Norton, MD, of Memorial Sloan-Kettering Cancer Center, said at the Sixth International Congress on Anti-Cancer Treatment.

ASCO LOS ANGELES--Two multi-institutional phase II studies of recombinant human anti-HER2/NEU antibody (rhuMAb HER2) in heavily pretreated stage IV breast cancer patients show some impressive responses, including some hepatic responses and a 25% response rate in patients given the antibody plus cisplatin (Platinol).