A Study to Learn About the Study Medicine PF-07220060 Together With Letrozole Compared to Letrozole Alone in Women Post Menopause

What this trial studies

The purpose of this study is to learn about the effects of the study medicine PF-07220060 plus letrozole, compared with the effects of taking letrozole alone without PF-07220060 for treatment of breast cancer. This study is seeking for participants who are: * women of age 18 years and older post menopause (either naturally or surgically). * confirmed to have Hormone receptor (HR) positive, Human epidermal growth factor receptor 2 (HER2) negative breast cancer. HER2 negative describes cells that have a small amount or none of a protein called HER2 on their surface.

Conditions in scope

• Breast Cancer

Interventions

• PF-07220060 (Drug) — PF-07220060 given as tablet by mouth twice a day for 14 days.
• letrozole (Drug) — Letrozole given as tablet by mouth once a day for 14 days

Who can join

Women only · Ages 18 Years and up

Inclusion criteria

• Postmenopausal women with histologically confirmed HR-positive and HER2-negative BC (per local assessment)
• Documented by estrogen receptor (ER) and/or progesterone receptor (PR)-positive disease by IHC or ISH
• Participants must have Ki-67 score \>/=10% with unilateral, invasive T1c-T4c, N0-N2, M0 BC
• Participants must be willing and able to undergo a baseline and Day 14 biopsy and must have an ECOG PS or 0 or 1.
• Participants must be treatment naive for the treatment of BC and cannot have had prior treatment with any systemic therapy (e.g., chemotherapy, hormonal therapy), radiation, surgery, or any investigational agents or use of hormone replacement therapy (HRT) or any other estrogen-containing medication (including vaginal estrogen) within 2 weeks prior to diagnostic tissue sample taken.

Exclusion criteria

• No prior systemic therapy, radiation, surgery, investigational therapy for treatment of breast cancer
• Certain medical conditions in the previous 6 months, for example: myocardial infarction, severe unstable angina, coronary/peripheral artery bypass graft, symptomatic congestive heart failure (New York Heart Association class III or IV), cerebrovascular accident, transient ischemic attack, symptomatic pulmonary embolism or other clinically significant episode of thromboembolism
• Lab abnormalities outside protocol specified parameters

Eligibility wording paraphrased from the public record. View the full criteria on ClinicalTrials.gov before contacting a site.

Where it’s happening

Showing the first 10 of 51 sites. See all sites on ClinicalTrials.gov.

Status & timeline

• Overall status: Completed
• Study type: Interventional
• Phase: PHASE2
• Start date: 2024-07-11
• Primary completion: 2025-07-10
• Last update posted: 2025-10-01
• First posted: 2024-06-18

Sponsor & contact

Lead sponsor: Pfizer (Industry)

For trial site contact information, use the official record at ClinicalTrials.gov. Contact details change frequently and the public record is the source of truth.

Outcome measures

Primary outcomes

• Rate of Ki-67 (Day 14)
  Centrally assessed biopsy

Related ClearedRx care

If you’re reading this trial because you have menopause symptoms now, you don’t have to wait for a trial to access evidence-based care. ClearedRx prescribes the same FDA-approved and compounded HRT products that have been studied in trials like this one for decades.