Breast CancerPhase 1/2NCT05262400
A Study to Learn About the Study Medicine (Called PF-07220060 in Combination With PF-07104091) In Participants With Breast Cancer and Solid Tumors
A Phase 1/2 study testing PF-07220060 + PF-07104091 combination dose escalation, PF-07104091 + PF-07220060 + fulvestrant dose expansion and PF-07104091 + PF-07220060 + letrozole dose expansion in people with Breast Cancer and Solid Tumors, run by Pfizer at 44 sites in 9 countries.
Trial summary
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called PF-07220060 and PF-07104091) in people with breast cancer. This clinical study consists of 2 parts (part 1 and part 2). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Breast Cancer, Solid Tumors
- What is being tested?
- PF-07220060 + PF-07104091 combination dose escalation, PF-07104091 + PF-07220060 + fulvestrant dose expansion and PF-07104091 + PF-07220060 + letrozole dose expansion
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 235 participants
- Where
- 44 sitesin 9 countries
- Study dates
- 14 Mar 2022to 26 Feb 2027
- Phase
- Phase 1/2
- Are there results?
- Not yet: the study is under way
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
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Part 1: Breast Cancer (BC)
- HR+, HER2- BC
- Refractory HR-positive/HER2-positive BC
- Part 1: Solid Tumors other than BC
- Part 2:
- HR-positive/HER2-negative BC
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- Lesion:
- Part 1: evaluable lesion (including skin or bone lesion only)
- Part 2: measurable lesion per RECIST v1.1
- Prior systemic Treatment
- Part 1: HR-positive/HER2-negative BC
- At least 1 line of SOC, including CDK4/6 inhibitor therapy and Endocrine Therapy, for advanced or metastatic disease.
- Prior chemotherapy in the metastatic setting is allowed.
- Part 1: HR-positive/HER2-positive BC
- At least 1 prior treatment of approved HER2 targeting therapy.
- Part 1: Solid Tumors other than BC
- Participants with no standard therapy available or for which no local regulatory approved standard therapy is available that would confer significant clinical benefit in the medical judgement of the investigator.
- Part 2A: At least 1 prior systemic therapy for advanced or metastatic disease, including CDK4/6 inhibitor treatment and ET.
- Parts 2B: At least 1 prior endocrine therapy for advanced or metastatic disease. Progression during treatment or within 12 months of completion of adjuvant endocrine therapy is acceptable.
- Part 2B: Up to 1 prior line of chemotherapy for advanced/metastatic disease is allowed.
- General Inclusion Criteria
- Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) 0 or 1
- Adequate renal, liver, and bone marrow function
- Resolved acute effects of any prior therapy to baseline severity
Who cannot join
- All Study Parts: Permanent treatment discontinuation from prior CDK 4 and/or CDK2 inhibitor due to treatment related toxicity.
- Part 2B and 1C: Prior treatment with any CDK 4/6 inhibitor, or SERDs (e.g. fulvestrant), or everolimus, or any agent whose mechanism of action is to inhibit the PI3K-mTOR pathway for advanced disease.
- Parts 2B and 2C: Prior treatment with any CDK4/6 inhibitor for advanced disease.
- Parts 2B and 2C: Prior treatment with an investigational endocrine therapy for advanced disease.
- Part 2C: Prior neoadjuvant or adjuvant treatment with a nonsteroidal aromatase inhibitor AI (ie, anastrozole or letrozole) with disease recurrence while on or within 12 months of completing treatment.
- Part 2C: Any prior systemic treatment for advanced disease.
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- Prior irradiation to >25% of the bone marrow
- Current use of drugs which have a risk for QTc prolongation
- Current use or anticipated need for food or drugs that are known strong CYP3A4/5, strong UGT2B7 or UGT1A9 inhibitors or inducers
- Participation in other studies involving investigational drug(s) within 4 weeks prior to study entry
- Participants with any other active malignancy within 3 years prior to enrollment except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ of the cervix, Bowen's disease
- Major surgery within 4 weeks prior to study entry
- Radiation therapy within 4 weeks prior to study entry.
- Clinically important hypertension
- Known or suspected hypersensitivity to PF-07220060, PF-07104091, letrozole, fulvestrant, or goserelin (or equivalent to induce chemical menopause if applicable)
- Known abnormalities in coagulation. Anticoagulation with subcutaneous heparin or prophylactic doses of anticoagulant are allowed
- Known active uncontrolled or symptomatic central nervous system (CNS) metastases
- Active inflammatory GI disease
- Current use or anticipated need for Proton Pump Inhibitors (PPI) within 14 days prior to first dose of the study intervention
- Previous high-dose chemotherapy requiring stem cell rescue
- Participants with active, uncontrolled bacterial, fungal, or viral infection, including hepatitis B virus (HBV), hepatitis C virus (HCV), and known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) related illness
- Other protocol specific exclusion criteria may apply
Trial locations and contacts
44 sites in 9 countries.
44 sites in 9 countries
United States12 sites
Massachusetts General Hospital
Boston, Massachusetts, 02114
Texas Oncology-Baylor Charles A. Sammons Cancer Center
Dallas, Texas, 75246
START Midwest
Grand Rapids, Michigan, 49546
The University of Texas MD Anderson Cancer Center
Houston, Texas, 77030
Saint Luke's Cancer Institute
Kansas City, Missouri, 64111
Administrative Address: UCLA Hematology/Oncology
Los Angeles, California, 90095
Ronald Reagan UCLA Medical Center
Los Angeles, California, 90095
UCLA Hematology/Oncology
Los Angeles, California, 90095
UCLA Hematology / Oncology-Parkside
Santa Monica, California, 90404
UCLA Hematology/Oncology-Santa Monica
Santa Monica, California, 90404
Swedish Medical Center
Seattle, Washington, 98104
Swedish Medical Center
Seattle, Washington, 98122
Brazil5 sites
Fundação Pio XII - Hospital de Câncer de Barretos
Barretos, São Paulo, 14784400
ONCOSITE - Centro de Pesquisa Clinica em Oncologia
Ijuí, Rio Grande do Sul, 98700-000
Centro Gaucho Integrado De Oncologia, Hematologia, Ensino E Pesquisa
Porto Alegre, Rio Grande do Sul, 90110-270
Centro de Pesquisa Clínica - Área Administrativa
Porto Alegre, Rio Grande do Sul, 90850-170
Clínica de Pesquisas e Centro de Estudos em Oncologia Ginecológica e Mamária Ltda
São Paulo, 01317-000
China5 sites
The First Hospital of Jilin University
Changchun, Jilin, 130021
West China Hospital, Sichuan University
Chengdu, Sichuan, 610041
Sir Run Run Shaw Hospital of Zhejiang University School of Medicine
Hangzhou, Zhejiang, 310016
Fudan University Shanghai Cancer Center
Shanghai, Shanghai Municipality, 200032
Tianjin Medical University Cancer Institute & Hospital
Tianjin, Tianjin Municipality, 300060
Spain5 sites
Hospital Universitari Vall d'Hebron
Barcelona, Barcelona [barcelona], 08035
Hospital Clínic de Barcelona
Barcelona, Catalunya [cataluña], 08036
Hospital Universitario 12 de Octubre
Madrid, Madrid, Comunidad de, 28041
Hospital Universitario HM Sanchinarro
Madrid, Madrid, Comunidad de, 28050
Hospital Universitario Virgen Del Rocio
Seville, 41013
Argentina4 sites
Centro Oncologico Korben
Buenos Aires, 1426
Clínica Universitaria Reina Fabiola
Córdoba, X50004FHP
Fundación CORI para la Investigación y Prevención del Cáncer
La Rioja, F5300COE
Clinica Viedma S. A
Viedma, Río Negro Province, R8500ACE
Bulgaria4 sites
Specialized Hospital for Active Treatment of Oncology - Haskovo
Haskovo, 6300
Complex Oncology Center - Plovdiv EOOD
Plovdiv, 4004
Multiprofile Hospital for Active Treatment Serdikamed EOOD
Sofia, Sofia (stolitsa), 1632
Complex Oncology Center - Vratsa
Vratsa, 3000
Czechia4 sites
Fakultni nemocnice Olomouc
Olomouc, Olomouc Region, 779 00
Fakultni nemocnice Bulovka
Prague, Praha 8, 180 81
Vseobecna fakultni nemocnice v Praze
Prague, 12808
Všeobecná fakultní nemocnice v Praze
Prague, 12808
Mexico3 sites
Mérida Investigación Clínica
Mérida, Yucatán, 97125
Instituto Nacional de Cancerologia
Mexico City, Mexico City, 14080
Hospital Universitario "Dr. Jose Eleuterio Gonzalez"
Monterrey, Nuevo León, 64460
South Africa2 sites
FARMOVS
Bloemfontein, Free State, 9301
Wits Clinical Research
Johannesburg, Gauteng, 2193
About this study
Official title: A PHASE 1B/2, OPEN-LABEL, MULTICENTER, DOSE ESCALATION AND DOSE EXPANSION STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND ANTITUMOR ACTIVITY OF PF-07220060 IN COMBINATION WITH PF-07104091 PLUS ENDOCRINE THERAPY IN PARTICIPANTS WITH ADVANCED SOLID TUMORS
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called PF-07220060 and PF-07104091) in people with breast cancer. This clinical study consists of 2 parts (part 1 and part 2). In part 1, we are seeking participants who:
- Have been diagnosed with Breast Cancer (BC) of either types:
- Have HR+, HER2- BC
- Refractory HR-positive/HER2-positive BC
- Have other solid tumors other than BC
Read more
In part 2, we are seeking participants who:
-Have HR-positive/HER2-negative BC Part 1 will include increasing doses of PF-07220060 with PF-07104091. In part 2, participants will take 1 of 2 study medicine combinations. This will help us decide the highest amount of study medicines that can be safety given to people. All participants in this study will receive PF-07220060 with PF-07104091 by mouth. We will compare participant experiences to help us determine if PF-07220060 with PF-07104091 is safe and effective. Participants will take part in this study for about 2 years. During this time, they will receive the study medicine, an x-ray imaging, and will be observed for safety and effects of the study medicines.
- Conditions
- Breast Cancer, Solid Tumors
- Being tested
- PF-07220060 + PF-07104091 combination dose escalation, PF-07104091 + PF-07220060 + fulvestrant dose expansion, PF-07104091 + PF-07220060 + letrozole dose expansion
- Keywords
- cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), estrogen receptor-positive/human epidermal growth factor receptor 2 negative (ER+/HER2-), estrogen receptor-positive/refractory hormone receptor positive (ER+/HER2+), hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-)
- 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-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07104091 + PF-07220060 + fulvestrant dose expansionDrug
PF-07104091 and PF-07220060 will be administered orally in combination with fulvestrant
PF-07104091 + PF-07220060 + fulvestrant dose expansionDrug
PF-07104091 and PF-07220060 will be administered orally in combination with fulvestrant
PF-07104091 + PF-07220060 + letrozole dose expansionDrug
PF-07104091 and PF-07220060 will be administered orally in combination with letrozole
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
PF-07220060 + PF-07104091 combination dose escalationDrug
PF-07104091 and PF-07220060 will be administered orally
| Study group | Role | What they receive |
|---|---|---|
| Part 1 Dose Escalation - Dose Level 4 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 2A | Experimental | PF-07220060 + PF-07104091 + Fulvestrant (ER+/HER2- Breast Cancer with at least 1 prior systemic therapy for advanced or metastatic disease, including CDK4/6 inhibitor treatment and Endocrine Therapy) Receives: Drug: PF-07104091 + PF-07220060 + fulvestrant dose expansion |
| Part 1 Dose Escalation - Dose Level 3 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 2B | Experimental | PF-07220060 + PF-07104091 + Fulvestrant (ER+/HER2- Breast Cancer with at least 1 prior endocrine therapy and up to 1 prior line of chemotherapy for advanced or metastatic disease and no prior treatment with any CDK4/6 inhibitor for advanced disease) Receives: Drug: PF-07104091 + PF-07220060 + fulvestrant dose expansion |
| Part 1 Dose Escalation - Dose Level 5 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 2C | Experimental | PF-07220060 + PF-07104091 + Letrozole (ER+/HER2- Breast Cancer with no prior treatment with any CDK4/6 inhibitor for advanced disease) Receives: Drug: PF-07104091 + PF-07220060 + letrozole dose expansion |
| Part 1 Dose Escalation - Dose Level 2 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 1 Dose Escalation - Dose Level 1 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 1 Dose Escalation - Dose Level 6 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 1 Dose Escalation - Dose Level 7 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
| Part 1 Dose Escalation - Dose Level 8 | Experimental | PF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) Receives: Drug: PF-07220060 + PF-07104091 combination dose escalation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Dose Escalation: Number of participants with Dose-limiting toxicities (DLT) during first cycle
Number of participants with DLTs, which are typically Grade 3 or higher adverse events will be summarized by dose level
Measured: Cycle 1 (28 days)
Number of participants with treatment emergent adverse events (AEs)
Measured: From baseline until end of study treatment or study completion (approximately 2 years)
Incidence of participants with clinical laboratory abnormalities
Measured: From baseline until end of study treatment or study completion (approximately 2 years)
Number of participants with vital signs abnormalities
Measured: From baseline until end of study treatment or study completion (approximately 2 years)
Number of participants with corrected QT (QTc) interval
Determine the effect of the drug on QT prolongation. The number and percentage of participants who experienced QT interval prolongation will be summarized by dose level
Measured: From baseline until end of study treatment or study completion (approximately 2 years)
Secondary outcomes (8)
Maximum plasma concentration (Cmax) of PF-07220060 and PF-07104091 together after a single dose and multiple dose
Measured: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Time to maximum plasma concentration (Tmax) of PF-07220060 and PF-07104091 together after a single dose and multiple dose
Measured: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Area under the concentration versus time curve from time zero to the last quantifiable time point prior to the next dose (AUClast) of PF-07220060 and PF-07104091 together
Measured: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Objective response rate (ORR) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
Percentage of participants with a best ORR of complete response (CR) or partial response (PR) using RECIST 1.
Measured: From baseline through disease progression or study completion (approximately 2 years)
To evaluate the preliminary antitumor activity of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole by time to event endpoints
Time from first assessment of event endpoint to last assessment of using RECIST 1.1
Measured: From baseline through time to event on study or study completion (approximately 2 years)
Duration of Response (DoR) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
DoR is defined as the time from first documentation of CR or PR to date of first documentation of progressive disease/pharmacodynamic (PD) or death due to any cause, whichever occurs first
Measured: From baseline through time to event on study or study completion (approximately 2 years)
Progression-Free Survival (PFS) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
PFS is defined as time from start date of treatment to the date of first documentation of PD or death due to any cause
Measured: From baseline through time to event on study or study completion (approximately 2 years)
Time to Progression (TTP) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
TTP is defined as the time from start date of treatment to the date of the first documentation of PD
Measured: From baseline through time to event on study or study completion (approximately 2 years)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Mar 2022
- Study start14 Mar 2022
- Primary completion26 Feb 2027 (estimated)
- Study completion26 Feb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- 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 1/2
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 235 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
- NCT05262400
- Sponsor's protocol ID
- C4391002
- Other IDs
- 2023-509504-15-00, 2023
- Status last verified
- Sep 2026
- First submitted
- 21 Feb 2022
- Last updated
- 14 Sep 2026
- Results posted
- No
- 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.
Study at a glance
From the registry record, last updated by the sponsor on 14 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A PHASE 1B/2, OPEN-LABEL, MULTICENTER, DOSE ESCALATION AND DOSE EXPANSION STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND ANTITUMOR ACTIVITY OF PF-07220060 IN COMBINATION WITH PF-07104091 PLUS ENDOCRINE THERAPY IN PARTICIPANTS WITH ADVANCED SOLID TUMORS
- ClinicalTrials.gov ID
- NCT05262400
- Acronym / sponsor ID
- C4391002
- Conditions
- Breast Cancer, Solid Tumors
- Keywords
- cyclin-dependent kinase 2 (CDK2), cyclin-dependent kinase 4 (CDK4), estrogen receptor-positive/human epidermal growth factor receptor 2 negative (ER+/HER2-), estrogen receptor-positive/refractory hormone receptor positive (ER+/HER2+), hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-)
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 235 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 14 Mar 2022 (actual)
- Primary completion
- 26 Feb 2027 (estimated)
- Study completion
- 26 Feb 2027 (estimated)
- First posted
- 2 Mar 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called PF-07220060 and PF-07104091) in people with breast cancer. This clinical study consists of 2 parts (part 1 and part 2). In part 1, we are seeking participants who:
- Have been diagnosed with Breast Cancer (BC) of either types:
- Have HR+, HER2- BC
- Refractory HR-positive/HER2-positive BC
- Have other solid tumors other than BC
In part 2, we are seeking participants who:
-Have HR-positive/HER2-negative BC Part 1 will include increasing doses of PF-07220060 with PF-07104091. In part 2, participants will take 1 of 2 study medicine combinations. This will help us decide the highest amount of study medicines that can be safety given to people. All participants in this study will receive PF-07220060 with PF-07104091 by mouth. We will compare participant experiences to help us determine if PF-07220060 with PF-07104091 is safe and effective. Participants will take part in this study for about 2 years. During this time, they will receive the study medicine, an x-ray imaging, and will be observed for safety and effects of the study medicines.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 11
| Arm | Type | Receives |
|---|---|---|
| Part 1 Dose Escalation - Dose Level 4 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 2A | Experimental | Drug: PF-07104091 + PF-07220060 + fulvestrant dose expansionPF-07220060 + PF-07104091 + Fulvestrant (ER+/HER2- Breast Cancer with at least 1 prior systemic therapy for advanced or metastatic disease, including CDK4/6 inhibitor treatment and Endocrine Therapy) |
| Part 1 Dose Escalation - Dose Level 3 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 2B | Experimental | Drug: PF-07104091 + PF-07220060 + fulvestrant dose expansionPF-07220060 + PF-07104091 + Fulvestrant (ER+/HER2- Breast Cancer with at least 1 prior endocrine therapy and up to 1 prior line of chemotherapy for advanced or metastatic disease and no prior treatment with any CDK4/6 inhibitor for advanced disease) |
| Part 1 Dose Escalation - Dose Level 5 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 2C | Experimental | Drug: PF-07104091 + PF-07220060 + letrozole dose expansionPF-07220060 + PF-07104091 + Letrozole (ER+/HER2- Breast Cancer with no prior treatment with any CDK4/6 inhibitor for advanced disease) |
| Part 1 Dose Escalation - Dose Level 2 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 1 Dose Escalation - Dose Level 1 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 1 Dose Escalation - Dose Level 6 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 1 Dose Escalation - Dose Level 7 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
| Part 1 Dose Escalation - Dose Level 8 | Experimental | Drug: PF-07220060 + PF-07104091 combination dose escalationPF-07220060 + PF-07104091 dose escalation (Breast Cancer or solid tumors) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (24 listed)
- Part 1: Breast Cancer (BC)
- HR+, HER2- BC
- Refractory HR-positive/HER2-positive BC
- Part 1: Solid Tumors other than BC
- Part 2:
Key exclusion criteria (22 listed)
- All Study Parts: Permanent treatment discontinuation from prior CDK 4 and/or CDK2 inhibitor due to treatment related toxicity.
- Part 2B and 1C: Prior treatment with any CDK 4/6 inhibitor, or SERDs (e.g. fulvestrant), or everolimus, or any agent whose mechanism of action is to inhibit the PI3K-mTOR pathway for advanced disease.
- Parts 2B and 2C: Prior treatment with any CDK4/6 inhibitor for advanced disease.
- Parts 2B and 2C: Prior treatment with an investigational endocrine therapy for advanced disease.
- Part 2C: Prior neoadjuvant or adjuvant treatment with a nonsteroidal aromatase inhibitor AI (ie, anastrozole or letrozole) with disease recurrence while on or within 12 months of completing treatment.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 1 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 2 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 3 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 4 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 5 |
| PF-07104091 + PF-07220060 + fulvestrant dose expansionPF-07104091 and PF-07220060 will be administered orally in combination with fulvestrant | Drug | Part 2A |
| PF-07104091 + PF-07220060 + fulvestrant dose expansionPF-07104091 and PF-07220060 will be administered orally in combination with fulvestrant | Drug | Part 2B |
| PF-07104091 + PF-07220060 + letrozole dose expansionPF-07104091 and PF-07220060 will be administered orally in combination with letrozole | Drug | Part 2C |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 6 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 7 |
| PF-07220060 + PF-07104091 combination dose escalationPF-07104091 and PF-07220060 will be administered orally | Drug | Part 1 Dose Escalation - Dose Level 8 |
Primary outcome
Dose Escalation: Number of participants with Dose-limiting toxicities (DLT) during first cycle
Time frame: Cycle 1 (28 days)
Number of participants with DLTs, which are typically Grade 3 or higher adverse events will be summarized by dose level
Number of participants with treatment emergent adverse events (AEs)
Time frame: From baseline until end of study treatment or study completion (approximately 2 years)
Incidence of participants with clinical laboratory abnormalities
Time frame: From baseline until end of study treatment or study completion (approximately 2 years)
Number of participants with vital signs abnormalities
Time frame: From baseline until end of study treatment or study completion (approximately 2 years)
Number of participants with corrected QT (QTc) interval
Time frame: From baseline until end of study treatment or study completion (approximately 2 years)
Determine the effect of the drug on QT prolongation. The number and percentage of participants who experienced QT interval prolongation will be summarized by dose level
8 secondary outcomes
Maximum plasma concentration (Cmax) of PF-07220060 and PF-07104091 together after a single dose and multiple dose
Time frame: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Time to maximum plasma concentration (Tmax) of PF-07220060 and PF-07104091 together after a single dose and multiple dose
Time frame: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Area under the concentration versus time curve from time zero to the last quantifiable time point prior to the next dose (AUClast) of PF-07220060 and PF-07104091 together
Time frame: Day 1 and Day 15 of Cycle 1 (each cycle is 28 days)
Objective response rate (ORR) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
Time frame: From baseline through disease progression or study completion (approximately 2 years)
To evaluate the preliminary antitumor activity of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole by time to event endpoints
Time frame: From baseline through time to event on study or study completion (approximately 2 years)
Duration of Response (DoR) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
Time frame: From baseline through time to event on study or study completion (approximately 2 years)
Progression-Free Survival (PFS) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
Time frame: From baseline through time to event on study or study completion (approximately 2 years)
Time to Progression (TTP) of PF-07220060 and PF-07104091 together in dose escalation and together in combination with fulvestrant or letrozole
Time frame: From baseline through time to event on study or study completion (approximately 2 years)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Sep 2026.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
44 sites in 9 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing PF-07220060 + PF-07104091 combination dose escalation, PF-07104091 + PF-07220060 + fulvestrant dose expansion and PF-07104091 + PF-07220060 + letrozole dose expansion in people with Breast Cancer and Solid Tumors, run by Pfizer at 44 sites in 9 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 24 inclusion and 22 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 14 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 44 sites in United States, Brazil, China, Spain, Argentina and 4 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Dose Escalation: Number of participants with Dose-limiting toxicities (DLT) during first cycle (time frame: Cycle 1 (28 days)). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Sep 2026.