Final results for the secondary efficacy endpoints of duration of treatment and clinical benefit rate demonstrated superiority in the palbociclib plus letrozole arm compared to the letrozole-only arm. Per the PALOMA-1 trial protocol, an initial assessment of overall survival (OS), a secondary endpoint, was also performed. Based on the events at the time of the assessment, a median OS of 37.5 months was observed in the combination arm versus 33.3 months for those who received letrozole alone, a difference of 4.2 months (HR = 0.813, 95% CI: 0.492, 1.345). This OS observation at the time of final PFS analysis was not statistically significant. A follow-up OS analysis will be conducted following the accrual of additional events.

About PALOMA-1

PALOMA-1 (also known as Study 1003 and TRIO-18) is a Phase 2 trial designed to assess PFS in post-menopausal women with ER+, HER2- advanced breast cancer receiving palbociclib (125 mg once daily for three out of four weeks in repeated cycles) in combination with letrozole versus letrozole alone (2.5 mg once daily on a continuous regimen). This trial consisted of two parts. Part 1 enrolled 66 patients with ER+, HER2- advanced breast cancer. Part 2 enrolled 99 additional patients whose tumors were selected for presence of biomarkers: cyclin D1 amplification and/or p16 loss. Final results from PALOMA-1 showed that statistically significant improvement in PFS was achieved for the study arm (palbociclib + letrozole) in both Parts 1 and 2. PFS is comprised of time from randomization to time of disease progression or death from any cause.

PALOMA-1 is conducted in collaboration with the Jonsson Cancer Center’s Revlon/UCLA Women’s Cancer Research Program, led by Dr. Dennis Slamon. PALOMA-1 is a multi-center trial with 101 global sites participating.

Palbociclib Development Program in ER+, HER2- Breast Cancer.

Above News form the website：http://press.pfizer.com/