Intermittent Letrozole Therapy in Postmenopausal Women With Metastatic Breast Cancer

Inclusion Criteria

• •Female
• •18 years of age or older
• •Postmenopausal
• •Histologically or cytologically confirmed adenocarcinoma of the breast with locally advanced or metastatic disease this is not considered amenable to curative treatment with elevation of CA 15-3 documented at the time of diagnosis of metastatic disease and prior to initiation of letrozole or anastrozole therapy
• •Current letrozole or anastrozole monotherapy with a documented CA 15-3 level that has decreased by at least 50% of the patients baseline
• •Letrozole or anastrozole must be discontinued at the time of study enrollment
• •Evidence of hormone sensitivity of primary or secondary tissue.
• •Measurable or nonmeasurable (but evaluable-defined as nontarget lesions) disease according to modified RECIST
• •Prior antiestrogen therapies including tamoxifen, steroidal AIs, nonsteroidal AIs, or fulvestrant in the adjuvant setting is allowed provided the patient is currently on letrozole or anastrozole monotherapy as first-line therapy for metastatic disease
• •Life expectancy of greater than 3 months
• •ECOG (Eastern Cooperative Oncology Group) Performance Status of 0,1, or 2
• •Normal organ and marrow function as outlined in protocol