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Novel CDK 4/6 Inhibitor Palbociclib plus Letrozole Significantly Prolonged Progression-Free Survival in Patients with Advanced Breast Cancer

Date：2014-04-10 【Size：Big Middle Small】

Pfizer Inc.have announced detailed results from the PALOMA-1 study, a randomized Phase 2 study of palbociclib (PD-0332991) in combination with letrozole. PALOMA-1 achieved its primary endpoint by significantly prolonging progression-free survival (PFS) compared with letrozole alone in post-menopausal women with estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) locally advanced or metastatic breast cancer. For women treated with the combination of palbociclib plus letrozole, the median PFS was 20.2 months, a statistically significant improvement compared to the 10.2 months of PFS in women who received letrozole alone (HR=0.488 [95% CI: 0.319, 0.748]; p=0.0004). These data will be presented today by Dr. Richard S. Finn, associate professor of medicine at University of California, Los Angeles (UCLA) at the American Association of Cancer Research (AACR) Annual Meeting 2014 in San Diego (Abstract #CT101).

"These data demonstrate the potential of palbociclib to be a major advance in the treatment of women with this type of advanced breast cancer," said Dr. Mace Rothenberg, senior vice president of Clinical Development and Medical Affairs and chief medical officer for Pfizer Oncology. "We are proud to be at the forefront of research and development with respect to this promising new class of investigational anticancer agents and have initiated a broad clinical development program for palbociclib that includes breast and non-breast cancers.”

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/

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