Pfizer Presents Phase 2 Data Which Shows Investigational Therapy PD-0332991 Plus Letrozole Improved Progression Free Survival vs Letrozole Alone

Pfizer Inc. PFE today announced randomized Phase 2 data that showed PD-0332991 (PD-991) in combination with letrozole significantly extended progression free survival (PFS) compared with letrozole alone in post-menopausal patients with estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) locally advanced or metastatic breast cancer. For patients treated with the combination of PD-991 plus letrozole, median PFS was 26.1 months, a statistically significant improvement compared to the median PFS in women who received letrozole alone, which was 7.5 months (HR=0.37 [95% CI: 0.21, 0.63]; P <0.001). These data were presented today and featured in a press conference at the 35^th Annual San Antonio Breast Cancer Symposium (Abstract #S1-6). Breast cancer is the most commonly diagnosed cancer^1 and the leading cause of cancer death among women worldwide.^2 Estrogen receptor positive, HER2- breast cancer represents approximately 60 percent of all cases of breast cancer.^3 Despite currently available treatments, survival rates for advanced or metastatic breast cancer remain low.^4