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A Recap of Last Year's Symposium
The 2006 San Antonio Breast Cancer Symposium sparked a number of important stories, from hormone replacement therapy to data that aided in a new drug's approval. Below are highlights from one year ago, with links provided at the end of each brief to CURE's in-depth coverage of each topic over the past year.
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Tykerb for HER2-Positive Breast Cancer
Herceptin (trastuzumab) is an antibody that targets HER2, a protein present in normal breast cells that is overly abundant in some malignant cells. Herceptin prolongs survival in patients with HER2-positive metastatic breast cancer, but the disease eventually progresses in most cases. Results from a phase III study show that Tykerb (lapatinib), an oral drug that targets both HER2 and HER1 (also know as the epidermal growth factor receptor), slows cancer growth when given in combination with Xeloda (capecitabine) in patients whose tumors progressed despite prior therapy that included Herceptin. The drug combination nearly doubled the time to progression—8.4 months compared with 4.4 months with Xeloda alone. A second study evaluated the combination of Tykerb plus Taxol (paclitaxel) in 35 patients with newly diagnosed inflammatory breast cancer, 30 of whom had HER2-positive disease. The combination was active, producing complete responses in 10 percent of patients, and partial responses in 67 percent of HER2-positive patients. Side effects associated with Tykerb include mild to moderate diarrhea, rash and fatigue. Ongoing trials will investigate Tykerb in combination with other hormonal or chemotherapy drugs, and a global trial launched in December to investigate Tykerb in the adjuvant setting, known as TEACH (Tykerb Evaluation After CHemotherapy), will assess its impact in early-stage disease. GlaxoSmithKline submitted Tykerb in combination with Xeloda to the Food and Drug Administration for approval in metastatic breast cancer, and a decision is expected by early 2007.
—Susan Peck, PhD
>> Read about Tykerb’s approval as well as CURE's recent feature on new breast cancer therapies.
Fewer Breast Cancer Cases Linked to Decline in HRT Use
By 2003, millions of women had stopped taking hormone replacement therapy following results from the Women's Health Initiative study that connected estrogen and progestin hormone therapy use to an increased risk of invasive breast cancer. That same year, breast cancer incidence dropped 7 percent-translating into 14,000 fewer women diagnosed in 2003 than in 2002. A new analysis says the dramatic reduction in HRT use is the reason. The analysis also revealed that for the type of breast cancer that is hormone sensitive, known as estrogen receptor-positive breast cancer, the decline was 12 percent for women ages 50 to 69, while estrogen receptor-negative tumors declined only 4 percent for the same age group. Researchers did stress, however, that since these data are based on population statistics, causation cannot be proven. Experts say other possible effects could include improvements in breast cancer screening that are detecting more noninvasive breast cancers, or changes in the use of selective estrogen receptor modulators, such as Evista (raloxifene) for osteoporosis-a drug recently proven to lower the risk of invasive breast cancer in postmenopausal women that was submitted for approval in this setting in early December. National cancer incidence data for 2004 will be available in spring 2007, at which time researchers can determine if the drop was a single event or a new trend.
—Melissa Weber
>> Read CURE's Fall 2007 cover story, which gives women clear answers about the link between hormone replacement therapy and breast cancer.
Zometa Reduces Aromatase Inhibitor-Associated Bone Loss
Aromatase inhibitors can significantly reduce the risk of recurrence in postmenopausal women with early breast cancer. But because these drugs block the production of estrogen, they can also cause an increased rate of bone loss, which may put some women at a higher risk for fractures. Two phase III studies found that adding the bisphosphonate Zometa (zoledronic acid) effectively prevents bone loss associated with aromatase inhibitors. More than 1,600 early-stage breast cancer patients in both the American Z-FAST trial and the international ZO-FAST trial received Zometa either when starting treatment with Femara (letrozole) or just after the emergence of clinically measurable bone loss. After one year, upfront Zometa resulted in a 5.1 percent improvement in bone density in the spine, and a 3.4 percent improvement in the hip compared with women who didn't receive Zometa until bone loss occurred. Interestingly, women in both groups had a similar incidence of bone fractures (about 2 percent). Zometa was safe and well-tolerated, with no serious side effects.
—Zach Moore, PhD
>> Watch for a cover story on bone health in the upcoming Winter 2007 issue of CURE.
CURE and Heal would like to give a special thanks to the following non-profit partners
for making this information available to their constituents:
American Cancer Society • People Living with Cancer
HER2 Support • Inflammatory Breast Cancer Research Fund • Men Against Breast Cancer
National Breast Cancer Coalition • Pink-Link
