Herceptin®:

On September 28, 1998 Genentech Inc. tannounced that it received approval from the U.S. Food and Drug Administration (FDA) for Herceptin®, also known by the generic name trastuzumab. Genentech Inc. said in their press release that they will provide Herceptin therapy for all patients in the United States, regardless of economic or insurance status, as they do with all their marketed products.

Approximately 164,000 women have metastatic breast cancer in the US today, according to estimates by Genentech, and the approval of Herceptin may offer the 25-30% of breast cancer patients who have this genetic alteration of the HER2 gene a better chance for a longer remission and survival.

Genentech announced earlier this week that, as of last Friday, they had enough Herceptin available to supply the hundreds of women who have been waiting for the limited supply of this drug through a lottery system devised by the National Cancer Institute. Genentech says today that the new biologic drug should be available to the general oncology medical community in October.

Herceptin is approved for use in patients with metastatic breast cancer whose tumors over express the HER2 (human epidermal growth factor receptor2) protein. The newly approved drug, which is best used in combination with paclitaxel for first line therapy, produces an increased amount of the growth factor receptor protein on the tumor cell surface. Herceptin may also be used as a single agent in second and third line therapy.

Herceptin was generally well tolerated by the 900 women who volunteered for the clinical trials. However, it was not without serious side effects for some women; patients who also received chemotherapy had increased incidences of cardiac toxicity, leukopenia, anemia, diarrhea, abdominal pain, and infections.

Continued clinical trials using Herceptin to fight other cancers are underway. A phase I study is currently being conducted that uses this drug in combination with a low-dose interleukin-2 plus in solid tumors to target most cancers with the exception of leukemias and lymphomas. Ongoing phase II studies involve treatment with Herceptin in recurrent or refractory ovarian or primary peritoneal (cells of the lining of the abdomen) carcinoma; however enrollment is currently closed while the NCI evaluates the initial data collected from this study.

The National Cancer Institute and Genentech hope to explore the use of Herceptin in a variety of malignancies, including gastric, endometrial, salivary gland, lung, pancreatic, prostate, and colorectal cancers and osteosarcoma. All patients with these types of cancers may not have high levels of HER2; but as many as 30% -40% of patients with some of these tumor types may overexpress the protein and be potential candidates for future clinical trials with Herceptin.