Women with hormone-sensitive early breast cancer who switched to Femara (letrozole) from placebo as part of a landmark trial experienced significant improvements in overall survival, disease-free survival and distant metastases, according to data presented at the 28th annual San Antonio Breast Cancer Symposium in Texas.
The analysis represents the first time that an aromatase inhibitor has demonstrated a benefit in starting therapy up to five years after the end of a patient taking tamoxifen, another medicine used in the treatment of hormone-related breast cancers, claims a Novartis release.
In this new analysis of the landmark MA-17 trial, postmenopausal women who switched from placebo to Femara experienced a 69 per cent reduction in the risk that their breast cancer would return (recurrence). There also was a 72 per cent reduction in the risk that the cancer would spread to a distant part of the body (metastasis). A 47 per cent reduction in the risk of dying from their disease was also observed. These observations must be confirmed by additional analysis and longer-term follow-up.
"These data provide the first clinical evidence that women can benefit from Femara even years after the completion of tamoxifen therapy. The findings may have a substantial impact on the overall treatment outcomes for postmenopausal women with early breast cancer," said Dr. Paul Goss, Massachusetts General Hospital in Boston and the lead investigator of the MA-17 trial.
The findings came from a new analysis of women who had been in the placebo arm of the MA-17 trial. In 2003, compelling results of an interim analysis showed that Femara reduced the risk of breast cancer coming back by 42 per cent compared to placebo. These data prompted an independent Data Safety Monitoring Board to recommend the unblinding of study results. Since then, approximately 1,655 women talking placebo have chosen to switch to Femara, while another 613 women did not pursue further treatment.
MA-17 is a phase III, international, double-blinded, randomised, multi-center trial. It is coordinated by the National Cancer Institute of Canada Clinical Trials Group at Queens University in Kingston, Ontario, Canada with funding from the Canadian Cancer Society and supported by Novartis.
Femara is a leading once-a-day oral aromatase inhibitor currently available in more than 90 countries worldwide. Femara is approved for extended adjuvant treatment of early breast cancer in postmenopausal women who have completed standard adjuvant tamoxifen therapy in 57 countries worldwide, including Europe as well as the United States.
Femara recently received approval in the United Kingdom for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. Approval for the adjuvant indication is expected in the US before the end of 2005 and in other countries in 2006.