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

AN INTERVENTIONAL, OPEN-LABEL, RANDOMIZED, MULTICENTER, PHASE 2 STUDY OF PF-07220060 PLUS LETROZOLE COMPARED TO LETROZOLE ALONE IN POSTMENOPAUSAL WOMEN 18 YEARS OR OLDER WITH HORMONE RECEPTOR-POSITIVE, HER2-NEGATIVE BREAST CANCER IN THE NEOADJUVANT SETTING

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06465368
Enrollment
121
Registered
2024-06-18
Start date
2024-07-11
Completion date
2025-07-10
Last updated
2026-07-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Breast Cancer

Keywords

human epidermal growth factor receptor 2 (HER2), hormone receptor (HR), HER2-negative, HR-Positive, Breast Cancer (BC), Neoadjuvant, Postmenopausal

Brief summary

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. In normal cells, HER2 helps control cell growth. Cancer cells that are HER2 negative may grow more slowly and are less likely to recur (come back) or spread to other parts of the body than cancer cells that have a large amount of HER2 on their surface. * not been treated for their cancer before this study. Participants will be randomly assigned (like flipping a coin) to receive the treatment (PF-07220060 plus letrozole) or letrozole alone. Both PF-07220060 and letrozole are taken by mouth. PF-07220060 will be taken twice a day for 14 days. Letrozole will be taken once a day for 14 days. Participants will have a screening period for up to 28 days. If deemed fit, they will receive study treatment for 14 days, and then will have a follow-up visit about 28 days after their last dose. All participants will have at least one biopsy during the study. Biopsy is the removal of cells or tissues for examining. All participants will have a biopsy on Day 14. Additional assessments for safety including blood draws and interviews done by the site staff will be completed during the study.

Interventions

PF-07220060 given as tablet by mouth twice a day for 14 days.

DRUGletrozole

Letrozole given as tablet by mouth once a day for 14 days

Sponsors

Pfizer
Lead SponsorINDUSTRY

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No

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

Design outcomes

Primary

MeasureTime frameDescription
Percentage of Participants With Complete Cell Cycle Arrest (CCCA) at Day 14Day 14CCCA was determined by antigen Kiel 67 (Ki-67) value as decided by Sponsor. Ki-67 was extensively used as a prognostic and predictive biomarker for cancer diagnosis and treatment. Ki-67 expression was measured by immunohistochemistry. Assessment at Day 14 was done in blinded manner by centrally assessed biopsy.

Secondary

MeasureTime frameDescription
Number of Participants With Treatment Emergent Adverse Events (TEAEs)From start of study intervention (Day 1) up to 35 days after the last dose of study intervention or start of subsequent anti-cancer therapy minus 1 day, whichever occurred first (approximately up to 49 days)An adverse event (AE) was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An serious adverse event (SAE) was defined as any untoward medical occurrence that, at any dose, met one or more of the criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity and was congenital anomaly/birth defect. AEs that occurred on or after the first dose of study treatment and before the end of treatment (35 days after last dose of study treatment or start of subsequent anti-cancer therapy minus 1 day, whichever occurred first) was considered TEAEs. All AEs (SAEs and all other AEs) were considered for evaluation.
Number of Participants With Treatment Emergent Serious Adverse Events (TESAEs)From start of study intervention (Day 1) up to 35 days after the last dose of study intervention or start of subsequent anti-cancer therapy minus 1 day, whichever occurred first (approximately up to 49 days)An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity and was congenital anomaly/birth defect. AEs that occurred on or after the first dose of study treatment and before the end of treatment (35 days after last dose of study treatment or start of subsequent anti-cancer therapy minus 1 day, whichever occurred first) was considered TEAEs.
Number of Participant With AEs Leading to Any Study Intervention DiscontinuationDuring study treatment (maximum up to 14 days)An AE was any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Circulating Tumor Deoxyribonucleic Acid (ctDNA) Methylation Tumor Fraction Values at Baseline and Day 14Baseline (the last measurement on or prior to date of the first dose of study intervention if the first dose is not missing, otherwise, on or prior to the randomization date), Day 14 (pre-dose)The methylation-based tumor fraction of a single sample was estimated from methylation signals across targeted regions from the methylation panel, was calibrated using training data including cancer free donors and participants with mixed cancer types. The method included a data-informed differentially methylated region selection targeting regions with high pan cancer signal to noise ratio. This value was an estimate of the proportion of the sample that was tumor derived and expressed as percentage of DNA. ctDNA methylation tumor fraction values were reported in percentage at Baseline and Day 14 were assessed from central laboratory.
Plasma Concentration (Ctrough) of PF-07220060 on Day 14Pre-dose (within 30 minutes before dosing) on Day 14Ctrough was pre-dose plasma concentration.
Plasma Concentration at the Time of Biopsy (Cperi-biopsy) of PF-07220060 on Day 14Within 1 hour before or 1 hour after biopsy on Day 14Cperi-biopsy was plasma concentration at the time of biopsy.
Change From Baseline in Antigen Ki-67 at Day 14Baseline (the last measurement on or prior to date of the first dose of study intervention if the first dose was not missing, otherwise, on or prior to the randomization date), Day 14 (pre-dose)Ki-67 was extensively used as a prognostic and predictive biomarker for cancer diagnosis and treatment. Ki-67 expression was measured by immunohistochemistry and expressed as percentage of cells. Assessment at baseline and Day 14 was done in blinded manner by centrally assessed biopsy.
Relative Reduction (%) of Ki-67 From Baseline at Day 14Baseline (the last measurement on or prior to date of the first dose of study intervention if the first dose was not missing, otherwise, on or prior to the randomization date), Day 14 (pre-dose)Ki-67 was extensively used as a prognostic and predictive biomarker for cancer diagnosis and treatment. Ki-67 expression was measured by immunohistochemistry. Assessment at baseline and Day 14 was done in blinded manner by centrally assessed biopsy. Relative reduction at Day 14 was calculated as:100 \*(1-Ki-67 at Day 14/Ki-67 at Baseline). Relative reduction was expressed in percentage reduction.

Countries

Australia, Belgium, France, Germany, Italy, Poland, Slovakia, South Korea, Spain, Sweden, Switzerland, Taiwan, United States

Contacts

STUDY_DIRECTORPfizer CT.gov Call Center

Pfizer

Baseline characteristics

Characteristic
Age, Continuous66.5 Years
STANDARD_DEVIATION 7.1
Ethnicity (NIH/OMB)
Hispanic or Latino
8 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
39 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
23 Participants
Race (NIH/OMB)
American Indian or Alaska Native
1 Participants
Race (NIH/OMB)
Asian
5 Participants
Race (NIH/OMB)
Black or African American
2 Participants
Race (NIH/OMB)
More than one race
0 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
Race (NIH/OMB)
Unknown or Not Reported
16 Participants
Race (NIH/OMB)
White
90 Participants
Sex: Female, Male
Female
121 Participants
Sex: Female, Male
Male
0 Participants

Adverse events

Event typeEG000
affected / at risk
EG001
affected / at risk
deaths
Total, all-cause mortality
0 / 590 / 62
other
Total, other adverse events
21 / 5916 / 62
serious
Total, serious adverse events
1 / 590 / 62

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jul 16, 2026