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Additional Benefits Touted for Clodronate as an Adjuvant Therapy For Breast Cancer at San Antonio Meeting
While a previous analysis of the study data showed that adjuvant treatment with clodronate reduced the occurrence of bone metastases and increased survival in this patient group, this new retrospective analysis showed that clodronate treatment also reduced the incidence of skeletal related events (SREs), morbidity, and mortality in the small group of patients who eventually developed bone metastases.
"Several studies have already confirmed the benefits of clodronate in reducing bone metastases and increasing survival in women with breast cancer, but this is the first study to demonstrate the added benefit of clodronate in the reduction of skeletal-related events," said Professor Trevor Powles, principal investigator of the study, previously head of breast cancer at the Royal Marsden Hospital, London, United Kingdom. "These results further support the benefits for use of clodronate for treatment of patients with early breast cancer."
Currently, clodronate is under priority review by the U.S. Food and Drug Administration for the adjuvant treatment of stage II and III breast cancer patients to reduce the occurrence of bone metastases.
Professor Powles' presentation was a retrospective analysis of a large-scale, randomized, double blind, placebo-controlled, multicenter study of 1,069 patients with primary, operable stage I-III breast cancer undertaken to evaluate the efficacy and safety of clodronate treatment for the prevention of bone metastases. Patients received clodronate (1600mg/day) or placebo for two years. Therapy began within six months of a primary diagnosis such as radiotherapy or surgery. Results demonstrated that the addition of clodronate to standard adjuvant therapy for stage II-III breast cancer reduced the risk of occurrence of bone metastases by 41% and improved overall survival by 26%. An earlier analysis of this study was published in the Journal of Clinical Oncology in 2002 and reported at the June 2004 American Society of Clinical Oncology meeting.
The analysis presented today in San Antonio evaluated the benefits of clodronate treatment for patients with primary breast cancer on the incidence of bone events such as fracture or the need for radiotherapy in patients whose cancer relapses in the bone. These data were collected from the charts of patients who had developed bone metastases during the 5-year study period (51 on clodronate and 73 on placebo). In these patients, the most notable difference in the treatment arm was the decrease in the need for radiation (47% vs 64%) and the decrease in the development of both non- vertebral/vertebral skeletal fractures (12% vs 22%, 12% vs 19% respectively).
"In addition to its established safety profile as a well-tolerated drug, clodronate has the advantage of oral administration," added Dr. Powles. "This may optimize patient compliance and overall clinical success." Mild-to-moderate diarrhea that was easily manageable was the only side effect that was statistically significantly greater for clodronate vs placebo.
About Breast Cancer
Breast cancer is the second leading cause of cancer deaths in women (after lung cancer) and the most common cancer among women, excluding non-melanoma skin cancers. The American Cancer Society estimates that in 2004, over 200,000 women in the United States will be diagnosed with breast cancer (stages I -IV). Bone is the initial site of metastasis in over 30% of patients with breast cancer. The median life expectancy in breast cancer patients following the appearance of bone metastases ranges from 18 to 21 months. Inhibiting metastases has the potential to impact clinical management and outcomes for these patients.
Source: Dr. Trevor Powles