A Randomized, Multicenter, Double-Blind Phase III Study of PD-0332991 Plus Letrozole Versus Placebo Plus Letrozole for the Treatment of Postmenopausal Women with ER (+), HER2 (-) Breast Cancer who have not Received any Prior Systemic Anti-Cancer Treatment for Advanced Disease


Breast - Female

Trial Phase

Phase III

Trial Purpose and Description

Trial Purpose

To demonstrate that the combination of PD-0332991 with letrozole is superior to placebo plus letrozole in prolonging PFS in postmenopausal women with ER(+)/HER2 (-) advance breast cancer who have not received any prior systemic anti-cancer therapies for their advanced/metastatic disease.

Participation Guidelines


Eligibility Criteria

Inclusion Criteria:

Adult women with locoregionally recurrent or metastatic disease not amenable to curative therapy.
Confirmed diagnosis of ER positive breast cancer
No prior systemic anti-cancer therapy for advanced ER+ disease.
Postmenopausal women
Measurable disease as per Response Evaluation Criterion in Solid Tumors [RECIST] or bone-only disease
Eastern Cooperative Oncology Group [ECOG] 0-2
Adequate organ and marrow function
Patient must agree to provide tumor tissue
Exclusion Criteria:

Confirmed diagnosis of HER2 positive disease
Patients with advanced, symptomatic, visceral spread that are at risk of life threatening complication in the short term
Known uncontrolled or symptomatic CNS metastases
Prior (neo)adjuvant treatment with letrozole or anastrozole with DFI &le 12-months from completion of treatment.
Prior treatment with any CDK 4/6 inhibitor.

Pfizer Inc., U.S. Pharmaceuticals Group
Last Updated:
Study HIC#: