For Healthcare Professionals

A Study of Palbociclib (PD-0332991) + Letrozole vs. Letrozole For 1st Line Treatment Of Postmenopausal Women With ER+/HER2- Advanced Breast Cancer (PALOMA-2)


About the study

The study is designed to compare the clinical benefit following treatment with letrozole in combination with PD-0332991 versus letrozole in combination with placebo in postmenopausal women with ER(+)/HER2(-) advanced breast cancer who have not received prior systemic anti cancer therapies for their advanced/metastatic disease.

Who can take part

You may be eligible to participate in the study if you meet the following criteria:


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


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

Enter your ZIP code/Postal code/PIN code to locate study sites near you:

How to Apply

Contact the study center to learn if this study is a good match for you.
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Study’s details


Breast Neoplasms

Age (in years)

18 - 200


Phase 3

Participants needed


Est. Completion Date

Aug 2023

Treatment type



Pfizer identifier


Study number


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