Pfizer's Breast Cancer Drug Shows Positive Results In Mid-stage Study

(RTTNews) - Drug giant Pfizer Inc. (PFE) Sunday said its experimental breast cancer drug in combination with standard treatment slowed breast cancer progression longer than the single-drug approved treatment.

Pfizer's said that women treated with the combination of palbociclib plus letrozole had progression free survival of 20.2 months, a statistically significant improvement compared to the 10.2 months in women who received letrozole alone.

"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.

Palbociclib received Breakthrough Therapy designation from the US FDA in April 2013, for the initial treatment of women with advanced or metastatic breast cancer. Pfizer continues to work with the FDA and other regulatory authorities to define the appropriate regulatory path forward for palbociclib.

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, 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.

Palbociclib is an investigational oral targeted agent that selectively inhibits cyclin-dependent kinases (CDKs) 4 and 6 to regain cell cycle control and block tumor cell proliferation.

PFE closed Friday's trading at $32.16, down $0.24 or 0.74%, on the NYSE. Teh stock gained $0.23 or 0.72% in after-hours trade.