December 7, 2010 — Long-anticipated results from a trial that seeks to identify which breast cancer patients might benefit when zoledronic acid (Zometa, Novartis) is added to their treatment regimens will be among the presentations at the 33rd Annual San Antonio Breast Cancer Symposium, being held December 8 to 12 in Texas.
Of all the studies at the meeting, the Adjuvant Treatment With Zoledronic Acid in Stage II/III Breast Cancer (AZURE) trial is most likely to be practice-changing, said Peter Ravdin, MD, PhD, codirector of the symposium in a pre-eeting press statement.
"AZURE is really fascinating because it is looking at whether or not bisphosphonates in a general sense will be effective adjuvant agents in breast cancer," Dr. Ravdin told Medscape Medical News.
Dr. Ravdin is director of the Comprehensive Breast Health Clinic at the Cancer Therapy & Research Center, University of Texas Health Science Center at San Antonio. He codirects the symposium with C. Kent Osborne, MD, director of the Dan L. Duncan Cancer Center, Baylor College of Medicine, in Houston.
Zoledronic acid is currently marketed as Zometa by Novartis for use in the treatment of bone metastases. It is also indicated for use in postmenopausal osteoporosis (as Reclast).
Dr. Ravdin said the AZURE trial is "an attempt to replicate" a smaller study of zoledronic acid — the Austrian Breast and Colorectal Cancer Study Group trial 12 (ABCSG-12) — which showed a 36% risk reduction in disease-free survival events with zoledronic acid in a cohort of premenopausal women treated with endocrine therapy; the median follow-up was 62 months.
The AZURE trial, which involves about 4000 patients, is designed to look at a broader range of patients than ABCSG-12, which had about 1600 patients.
Dr. Ravdin explained that ABCSG-12 was restricted to premenopausal women who were estrogen-receptor positive and recipients of hormone therapy and the lutenizing hormone-releasing hormone agonist goserelin for ovarian suppression.
"AZURE basically includes all patients with stage II/III breast cancer, regardless of age, receptor status, and so on," he explained. The design of AZURE calls for patients to be randomized to receive adjuvant chemotherapy and/or endocrine therapy with or without zoledronic acid. The trial will determine whether zoledronic acid improves disease-free and bone-metastasis-free survival.
The AZURE data will be presented by Robert E. Coleman, MD, from the academic unit of clinical oncology at the Weston Park Hospital in Sheffield, United Kingdom.
A session on December 10, said Dr. Ravdin, asks: Can we move beyond trastuzumab in the treatment of HER2-positive breast cancer?
Dr. Ravdin explained the importance of exploring agents other than trastuzumab in HER2-positive and HER2-overexpressing patients. "Trastuzumab only targets the HER2 receptor, but there is a family of HER2 proteins," he explained. "The new drugs have a broader set of targets — not just the HER2 receptor alone."
One such agent is lapatinib (Tykerb, GlaxoSmithKline), a dual HER2/EGFR tyrosine kinase inhibitor. Lapatinib is approved for use in combination with capecitabine (Xeloda) for the treatment of patients with advanced or metastatic breast cancer whose tumors overexpress HER2 and who have received previous therapy that included an anthracycline, a taxane, or trastuzumab.
During this session, there will be a presentation that compares lapatinib and trastuzumab when both targeted therapies are used in combination with chemotherapy for patients with early breast cancer. It is the first-ever study that directly compares the 2 agents, said Dr. Ravdin.
Lead author Michael Untch, MD, who is head of the multidisciplinary breast cancer department at the Helios Clinic in Berlin, Germany, will make the presentation.
One of the goals of the study, known as GeparQuinto, is to see if lapatinib can improve the pathological complete response rate when added to anthracycline/taxane-based neoadjuvant chemotherapy. This has already been shown for trastuzumab.
Another study in the same session examines whether or not the combination of pertuzumab and trastuzumab has superior antitumor activity in women with early HER2-positive breast cancer than trastuzumab alone. These phase 2 results are from the Neoadjuvant Treatment With Herceptin and Pertuzumab (NEOSPHERE) trial, and will be presented by Luca Gianni, MD, director of medical oncology at the Fondazione IRCCS Istituto dei Tumori di Milano in Milan, Italy.
Yet another study will look at whether the combination of lapatinib, trastuzumab, and paclitaxel improves tumor response rates more than any of the agents alone in patients with HER2-positive breast cancers. Lead researcher José Baselga, MD, PhD, chief of the Division of Hematology and Oncology and associate director of the Massachusetts General Hospital Cancer Center in Boston, will present the study.
AIs and Toxicities, Including Cardiovascular Events
A couple of studies at the meeting will look at the toxicities related to adjuvant endocrine therapy in postmenopausal breast cancer patients.
The most important study, said Dr. Ravdin, is a meta-analysis that seeks to determine differences between serious adverse events, including cardiovascular ones, associated with aromatase inhibitors (AIs) and those associated with tamoxifen.
The study also explores whether these adverse events can be ameliorated by switching to AIs after 2 to 3 years of tamoxifen.
"Finally we have enough trials and enough follow-up to address the cardiovascular safety of aromatase inhibitors relative to tamoxifen," said Dr. Ravdin about the meta-analysis.
The study will be presented by Eitan Amir, MD, from the Department of Medical Oncology at the Princess Margaret Hospital in Toronto, Ontario.
In the same session, on December 9, there will be presentations on obesity and the effectiveness of adjuvant therapy. Included will be a presentation that reviews overall survival and patient hormone-receptor status in American women.
That study will be presented by Joseph A. Sparano, MD, professor of medicine and women's health at Albert Einstein Medical College of Medicine and associate chair of the Department of Oncology at Montefiore Medical Center in the Bronx, New York.
Dr. Ravdin singled out 2 other presentations of high value to meeting goers and clinicians who follow the meetings' news.
The final 5-year analysis of the multinational FinXX study looks at whether the integration of capecitabine into a sequential docetaxel followed by cyclophosphamide + epirubicin + 5-fluorouracil adjuvant regimen might improve clinical outcome for patients with medium- to high-risk early breast cancer. "Capecitabine is not used much in North America," said Dr. Ravdin, adding that it is therefore worthwhile for Americans to take a look at efficacy with this regimen.
The Sequencing of Chemotherapy and Radiotherapy in Adjuvant Breast Cancer Treatment (SECRAB) prospective randomized trial compares sequential with synchronous chemotherapy and radiotherapy. "Classically, we give chemotherapy first and then radiation," said Dr. Ravdin about the treatment sequence in much of early breast cancer. This is the "first major study of modern chemotherapy" to examine this sequencing, but he noted that there is a caveat — taxanes were not studied.
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Cite this: What's Hot at the 2010 San Antonio Breast Cancer Symposium - Medscape - Dec 07, 2010.