Breast CancerPhase 2NCT06465368
A Study to Learn About the Study Medicine PF-07220060 Together With Letrozole Compared to Letrozole Alone in Women Post Menopause
A Phase 2 study testing PF-07220060 and letrozole in people with Breast Cancer, run by Pfizer at 51 sites in 13 countries.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Breast Cancer
- What is being tested?
- PF-07220060 and letrozole
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 121 participants
- Where
- 51 sitesin 13 countries
- Study dates
- 11 Jul 2024to 10 Jul 2025
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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
Trial locations and contacts
51 sites in 13 countries.
51 sites in 13 countries
United States10 sites
Advocate Good Shepherd Hospital
Barrington, Illinois, 60010
AMG -Crystal Lake
Crystal Lake, Illinois, 60014
Baylor College of Medicine Medical Center
Houston, Texas, 77030
Baylor St. Luke's Medical Center
Houston, Texas, 77030
Ben Taub General Hospital
Houston, Texas, 77030
Harris Health System - Smith Clinic
Houston, Texas, 77054
O'Quinn Medical Tower - McNair Campus
Houston, Texas, 77054
Advocate Lutheran General Hospital
Park Ridge, Illinois, 60068
Advocate Medical Group
Park Ridge, Illinois, 60068
START San Antonio
San Antonio, Texas, 78229
Spain10 sites
Hospital Universitari Vall d'Hebron
Barcelona, Barcelona [barcelona], 08035
Hospital de la Santa Creu i Sant Pau
Barcelona, Catalunya [cataluña], 08041
Hospital Clínico Universitario Virgen de la Arrixaca
El Palmar, Murcia, Región de, 30120
Hospital General Universitario de Elche
Elche, Alicante, 03203
Hospital Universitario San Cecilio
Granada, 18016
Hospital Jerez de la Frontera
Jerez de la Frontera, Cádiz, 11407
Hospital General Universitario Gregorio Marañon
Madrid, Madrid, Comunidad de, 28009
Hospital Universitario 12 de Octubre
Madrid, Madrid, Comunidad de, 28041
Hospital Universitario HM Sanchinarro
Madrid, 28050
Hospital Universitario Virgen de la Victoria
Málaga, Málaga, 29010
France7 sites
Centre de Cancérologie du Grand Montpellier
Montpellier, Languedoc-roussillon, 34070
Centre Hospitalier Lyon Sud
Pierre-Bénite, Rhône, 69310
Centre Eugène Marquis Rennes - Centre de Lutte Contre le Cancer
Rennes, Ille-et-vilaine, 35042
CHU de Saint-Etienne
Saint Priest En Jarez, Pays de la Loire Region, 42271
HCL, Centre Hospitalier Lyon Sud
Saint-Genis-Laval, Rhône, 69230
Institut de Cancérologie de l'Ouest
Saint-Herblain, Loire-atlantique, 44805
Gustave Roussy
Villejuif, Val-de-marne, 94800
Italy5 sites
Ospedale Antonio Perrino
Brindisi, 72100
Azienda USL Toscana Nord Ovest_Ospedale Civile di Livorno
Livorno, Tuscany, 57124
IRCCS - Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori"
Meldola, Emilia-Romagna, 47014
Fondazione IRCCS San Gerardo dei Tintori
Monza, Lombardy, 20900
Azienda Ospedaliero Universitaria Maggiore della Carità
Novara, 28100
Poland4 sites
Pratia MCM Krakow
Krakow, Lesser Poland Voivodeship, 30-727
Wojewodzki Szpital im. Sw. Ojca Pio w Przemyslu
Przemyśl, Podkarpackie Voivodeship, 37-700
AIDPORT Sp. z o.o.
Skórzewo, Greater Poland Voivodeship, 60-185
Narodowy Instytut Onkologii im. Marii Sklodowskiej-Curie - Panstwowy Instytut Badawczy w Warszawie
Warsaw, Masovian Voivodeship, 02-781
Switzerland3 sites
Tumor Zentrum Aarau
Aarau, Canton of Aargau, 5000
Kantonsspital Baden
Baden, 5404
University Hospital Basel
Basel, Canton of Basel-City, 4031
Australia2 sites
Peter MacCallum Cancer Centre
Melbourne, Victoria, 3000
Royal Melbourne Hospital
Parkville, Victoria, 3052
Belgium2 sites
Institut Jules Bordet
Anderlecht, Bruxelles-capitale, Région de, 1070
UZ Leuven
Leuven, Vlaams-brabant, 3000
Slovakia2 sites
Narodny onkologicky ustav
Bratislava, 833 10
Nemocnica AGEL Komarno
Komárno, Nitra Region, 945 05
Sweden2 sites
Sjukhuset I Gävle
Gävle, Gävleborgs LÄN [se-21], 80187
Akademiska sjukhuset
Uppsala, Uppsala LÄN [se-03], 751 85
Taiwan2 sites
National Cheng Kung University Hospital
Tainan, 704
Mackay Memorial Hospital
Taipei, 10449
Germany1 site
CaritasKlinikum Saarbrücken St. Theresia
Saarbrücken, Saarland, 66113
South Korea1 site
Seoul National University Hospital
Seoul, Seoul-teukbyeolsi [seoul], 03080
About this study
Official title: 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
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:
Read more
- 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.
- Conditions
- Breast Cancer
- Being tested
- PF-07220060, letrozole
- Keywords
- human epidermal growth factor receptor 2 (HER2), hormone receptor (HR), HER2-negative, HR-Positive, Breast Cancer (BC), Neoadjuvant, Postmenopausal
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
PF-07220060Drug
PF-07220060 given as tablet by mouth twice a day for 14 days.
letrozoleDrug
Also called Femara
Letrozole given as tablet by mouth once a day for 14 days
| Study group | Role | What they receive |
|---|---|---|
| Arm A/Experimental/PF-07220060 plus letrozole | Experimental | PF-07220060 given as tablet by mouth twice a day for 14 days. Letrozole given as tablet by mouth once a day for 14 days. Receives: Drug: PF-07220060; Drug: letrozole |
| Arm B/Control/letrozole | Active comparator | Letrozole given by mouth once a day for 14 days. Receives: Drug: letrozole |
What is being measured
The primary outcome is the main question the study is designed to answer.
Percentage of Participants With Complete Cell Cycle Arrest (CCCA) at Day 14
CCCA 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.
Measured: Day 14
Secondary outcomes (8)
Number of Participants With Treatment Emergent Adverse Events (TEAEs)
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.
Measured: 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)
Number of Participants With Treatment Emergent Serious Adverse Events (TESAEs)
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.
Measured: 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)
Number of Participant With AEs Leading to Any Study Intervention Discontinuation
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.
Measured: During study treatment (maximum up to 14 days)
Circulating Tumor Deoxyribonucleic Acid (ctDNA) Methylation Tumor Fraction Values at Baseline and Day 14
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.
Measured: Baseline (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)
Plasma Concentration (Ctrough) of PF-07220060 on Day 14
Ctrough was pre-dose plasma concentration.
Measured: Pre-dose (within 30 minutes before dosing) on Day 14
Plasma Concentration at the Time of Biopsy (Cperi-biopsy) of PF-07220060 on Day 14
Cperi-biopsy was plasma concentration at the time of biopsy.
Measured: Within 1 hour before or 1 hour after biopsy on Day 14
Change From Baseline in Antigen Ki-67 at Day 14
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.
Measured: Baseline (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)
Relative Reduction (%) of Ki-67 From Baseline at Day 14
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.
Measured: Baseline (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)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Jun 2024
- Study start11 Jul 2024
- Primary completion10 Jul 2025
- Study completion10 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Breast CancerStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 121 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06465368
- Sponsor's protocol ID
- C4391025
- Other IDs
- 2024-512848-30-00
- Status last verified
- Jun 2026
- First submitted
- 13 Jun 2024
- Last updated
- 15 Jul 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.