The U.S. Food and Drug Administration recently approved the drug U.S. FDA Approves Faslodex for Advanced Breast Cancer (dateline July 8, 2002) | Breast Health News | Imaginis - The Women's Health & Wellness Resource Network

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U.S. FDA Approves Faslodex for Advanced Breast Cancer (dateline July 8, 2002)

The U.S. Food and Drug Administration recently approved the drug Faslodex (generic name, fulvestrant) to help treat advanced breast cancer. Faslodex, which received approved for women who have become resistant to treat with the standard breast cancer drug tamoxifen (trade name, Nolvadex), is administered as an injection in the muscle. According to AstraZeneca, the maker of Faslodex, the FDA approval provides another advance in the treatment of late-stage breast cancer.

Advanced, or metastatic, breast cancer occurs when cancer has spread past the breast and axillary (armpit) lymph nodes to invade other areas of the body, such as the lungs or liver. Approximately 10% of the 200,000 cases of breast cancer diagnosed each year have already progressed to the advanced stage. Recently, several studies have shown promising results with new drugs or drug combinations that may help slow the progression of breast cancer and help women with advanced breast cancer live longer.

The FDA's approval of Faslodex came after two clinical trials showed Faslodex to be at least as effective as Arimidex (generic name, anastrozole), another drug used to treat advanced breast cancer in women who have become resistant to tamoxifen. In a North American clinical trial comparing Faslodex and Arimidex, lead researcher Kent Osborne, MD, Director of the Breast Center at Baylor College of Medicine and his colleagues found that 17% of advanced breast cancer patients responded to Faslodex--the same percentage that responded to Arimidex. In a similar European trial, 20% of advanced breast cancer patients responded with Faslodex, compared to 15% with Arimidex.

Both clinical trials also found that Faslodex slowed the progression of the cancer. In the North American trial, cancer progression took 5.5 months with Faslodex compared with 3.5 months with Arimidex. In the European trial, progression was 5.5 months with Faslodex compared with 5.2 months with Arimidex.

"Advanced breast cancer treatment has significantly improved through sequential treatment with different and novel hormonal therapies. The introduction of 'Faslodex' expands that sequence, providing women with another treatment option that works in a uniquely different way," said Dr. George Blackledge, VP, Medical Director of Oncology for AstraZeneca, in a company news release.

Many breast cancers contain estrogen receptors within their cells. To survive and reproduce, these cancers depend on the hormone estrogen. Researchers have found that using hormonal agents, (such as tamoxifen, Arimidex, and now Faslodex) prevents estrogen from binding to these receptors in cancer cells helps slow the growth of cancer. Faslodex works differently than both tamoxifen and Arimidex. Instead of blocking estrogen from estrogen receptors in breast cancer cells as tamoxifen does or preventing the production of estrogen in adrenal glands like Arimidex, Faslodex degrades (i.e., destroys) estrogen receptors.

According to AstraZeneca, mild reactions to Faslodex injections also occur in some patients, with pain and inflammation being the most common results. Other side effects of Faslodex include:

  • vomiting
  • constipation or diarrhea
  • abdominal pain
  • headache
  • back pain
  • hot flushes
  • sore throat

AstraZeneca is currently conducting a study comparing Faslodex to tamoxifen and plans to release the results soon.

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