study of safety and efficacy of letrozole monotherapy as second-line endocrine therapy in postmenopausal patients with advanced breast cancer who received previous anti-estrogen treatment

Conditions: Postmenopausal Women With Advanced Breast Cancer

Summary: * safety and efficacy of letrozole 2.5 mg/day monotherapy as second-line endocrine therapy in postmenopausal patients with advanced breast cancer who received previous anti-estrogen treatment * to investigate changes in blood drug concentrations and blood hormone kinetics. * to investigate gene polymorphisms of cyp2a6, an enzyme involved in the metabolism of letrozole


Eligibility criteria:
inclusion criteria: * patients with histologically or cytologically documented breast cancer * patients with progressive breast cancer (advanced breast cancer, locoregional recurrence not operative, or metastatic breast cancer) * patients with hormone receptor (er and/or pgr) positive or both unknown. * postmenopausal patients between ages 20 and 79 years, inclusive * patients with a history of adjuvant therapy or advanced breast cancer treated with anti-estrogens * patients with documented measurable or evaluable lesions. * patients with sufficient organ function to evaluate the safety * patients whose performance status (ps) is 0～2 exclusion criteria: * patients with diffuse lymphangitis carcinomatosa of the lung or cns involvement, liver metastasis occupying more than one third of the liver, or inflammatory breast cancer * patients with other concurrent or previous malignant disease (excluding contralateral breast cancer, in situ carcinoma of cervix uteri, and adequately treated basal or squamous cell carcinoma of the skin) * patients in whom one of the following is the sole manifestation of disease: hilar enlargement, pleural effusion and ascites * patients with only blastic bone metastases or a mixed blastic and lytic bone metastases at the same site and no other measurable or evaluable lesions * patients with serious current disease such as uncontrolled cardiac diseases and/or uncontrolled diabetes mellitus by any medications (including a historical serious cardiac disease) * patients with adrenal insufficiency (treated or untreated) or cushing's syndrome * patients with any of the following previous treatments 1. chemotherapy for metastatic and/or locoregional recurrent disease 2. previous adjuvant endocrine therapy other than ovariectomy, anti-estrogen treatment, lh-rh analogues or radiation castration 3. previous first-line endocrine therapy (e.g., aromatase inhibitors and gastagens) for the treatment of metastatic and/or locoregional recurrent breast cancer other than anti-estrogen or lh-rh analogues treatment 4. patients who have not recovered from toxicity caused by previous therapy 5. for patients on investigational drugs, adequate wash-out periods of at least 7 days in the case of topical investigational drugs and at least 30 days in the case of systemic 6. previous bisphosphonate therapy started within 6 months without any other measurable or evaluable lesions 7. patients who have not stopped treatment with other anti-estrogen or anti-cancer drugs (other than bisphosphonates) before starting the trial medication other protocol-defined inclusion/exclusion criteria may apply.

Keywords: aromatase inhibitor letrozole breast cancer