A Study of R1507 in Combination With Letrozole in Postmenopausal Women With Advanced Breast Cancer

An Open Label Study to Evaluate the Safety, Tolerability and Effect on Tumor Response of R1507 in Combination With Letrozole in Postmenopausal Women With Advanced Breast Cancer.

This study aim was to determine the safety and efficacy of R1507 in combination with letrozole in patients with advanced breast cancer. In the first part of the study a cohort of patients with advanced breast cancer received letrozole 2.5mg po daily in combination with R1507 16mg/kg every 3 weeks.

Inclusion Criteria:

• postmenopausal female patients;
• stage IV or locally advanced breast cancer;
• measurable disease;
• letrozole failure (Part 2);
• Eastern Cooperative Oncology Group (ECOG) performance status <=2.

Exclusion Criteria:

• previous chemotherapy for metastatic breast cancer;
• concurrent antibody or immunotherapy for advanced disease, within 4 weeks prior to receipt of study drug;
• history of primary malignancy in 5 years prior to study, excluding adequately treated basal or squamous cell cancer of skin, or cancer in situ of cervix;
• concurrent radiotherapy, or radiotherapy within 28 days prior to receipt of study drug.