A Study to Learn About the Study Medicine Called PF-08032562 in People With Advanced or Metastatic Solid Tumors

A PHASE 1 DOSE ESCALATION AND EXPANSION STUDY TO EVALUATE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND ANTI-TUMOR ACTIVITY OF PF-08032562 IN PARTICIPANTS WITH ADVANCED OR METASTATIC SOLID TUMORS

The purpose of this study is to learn about the safety and effects of the study medicine when given alone or together with other anti-cancer therapies. Anti-cancer therapy is a type of treatment to stop the growth of cancer. This study also aims to find the best amount of study medication.

This study is seeking participants that have advanced or metastatic breast cancer (BC), or advanced or metastatic colorectal cancer (CRC).

All participants in this study will take the study medication (PF-08032562) as pill by mouth. This will be repeated for 28-day cycles.

Depending on which part of the study participants are enrolled into, they will receive the study medication PF-08032562 alone or in combination with other anti-cancer medications. The study medication (PF-08032562) will be taken by mouth (PO) in combination with other anti-cancer medications given in the study clinic by intramuscular (IM) injection into the muscle or intravenous (IV) infusion that is directly injected into the veins at different times (depending on the treatment) during the 28-day cycle. The study may also test different schedules.

Study Overview

• Status: Recruiting
• Conditions: Colorectal Cancer; Advanced Breast Cancer; Triple Negative Breast Cancer; Metastatic Colorectal Adenocarcinoma; Metastatic Breast Cancer (HR+/ HER2-)
• Intervention / Treatment: Drug: PF-08032562; Drug: Fulvestrant; Drug: Cetuximab; Drug: Fluorouracil; Drug: Oxaliplatin; Drug: Leucovorin; Drug: Bevacizumab

• Study Type: Interventional
• Enrollment (Estimated): 260
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Pfizer CT.gov Call Center; Phone Number: 1-800-718-1021; Email: ClinicalTrials.gov_Inquiries@pfizer.com

Study Locations

• United States
  • California
    • Duarte, California, United States, 91010
      • Recruiting
      • City of Hope (City of Hope National Medical Center, City of Hope Medical Center)
  • Michigan
    • Grand Rapids, Michigan, United States, 49546
      • Recruiting
      • START Midwest, LLC
  • New York
    • Long Island City, New York, United States, 11101
      • Recruiting
      • Memorial Sloan Kettering Cancer Center - Investigational Drug Service Pharmacy
    • New York, New York, United States, 10065
      • Recruiting
      • Memorial Sloan Kettering Cancer Center - Main Campus
    • New York, New York, United States, 10021
      • Recruiting
      • Memorial Sloan Kettering Cancer Center - David H. Koch Center for Cancer Care (74th Street).
    • New York, New York, United States, 10022
      • Recruiting
      • Memorial Sloan Kettering Cancer Center 53rd street.
  • Texas
    • Conroe, Texas, United States, 77384
      • Recruiting
      • The University of Texas MD Anderson Cancer Center - Conroe
    • Houston, Texas, United States, 77030
      • Recruiting
      • The University of Texas - M.D. Anderson Cancer Center
    • Houston, Texas, United States, 77079
      • Recruiting
      • The University of Texas, MD Anderson Cancer Center - West Houston
    • League City, Texas, United States, 77573
      • Recruiting
      • The University of Texas, MD Anderson Cancer Center - League City
    • San Antonio, Texas, United States, 78229
      • Recruiting
      • START San Antonio
    • Sugar Land, Texas, United States, 77478
      • Recruiting
      • The University of Texas, MD Anderson Cancer Center - Sugar Land
  • Utah
    • West Valley City, Utah, United States, 84119
      • Recruiting
      • START Mountain Region

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• 18 years of age or older
• Advanced or metastatic cancer of the breast or colon Part 1A: metastatic or advanced breast cancer or colorectal cancer for which no standard therapy is available Part 1B: metastatic or advanced breast cancer with disease progression after at least 1 line of treatment with an endocrine therapy and CDK4/6 inhibitor in the advanced or metastatic setting Part 1C: metastatic or advanced colorectal cancer with at least having received chemotherapy and/or targeted therapy if appropriate Part 1D: metastatic or advanced colorectal cancer without any prior chemotherapy for advanced or metastatic disease Part 2A: metastatic or advanced breast cancer with disease progression after at least 1 prior line of CDK4/6 inhibitor and at least 1 prior line of endocrine therapy Part 2B: metastatic or advanced colorectal cancer with at least having received chemotherapy and/or targeted therapy if appropriate Part 2C: metastatic or advanced colorectal cancer without any prior chemotherapy for advanced or metastatic disease
• Measurable disease
• ECOG performance status 0 or 1

Exclusion Criteria:

• Active malignancy within 3 years prior to enrollment
• Known symptomatic brain metastases requiring steroids
• Advanced/metastatic, symptomatic, visceral spread, that are at risk of life-threatening complications in the short term
• Prior irradiation to >25% of the bone marrow
• Hypertension that cannot be controlled by optimal medical therapy
• Renal impairment
• Hepatic dysfunction
• Cardiac abnormalities
• Active bleeding disorder
• Active or history of clinically significant GI disease
• Other unacceptable abnormalities as defined by protocol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part 1 Dose Escalation Cohort 1A; PF-08032562 monotherapy dose escalation for participants with advanced or metastatic BC or CRC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO)
Experimental: Part 1 Dose Escalation Cohort 1B; Combination (PF-08032562 + fulvestrant) dose escalation for participants with advanced or metastatic BC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Fulvestrant; Selective Estrogen Receptor Degrader (SERD); Other Names: Faslodex
Experimental: Part 1 Dose Escalation Cohort 1C; Combination (PF-08032562 + cetuximab) dose escalation for participants with advanced or metastatic CRC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Cetuximab; Monoclonal antibody (EGFR inhibitor); Other Names: Erbitux; Enlituo
Experimental: Part 1 Dose Escalation Cohort 1D; Combination (PF-08032562 + [FOLFOX + bevacizumab]) dose escalation for participants with advanced or metastatic CRC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Fluorouracil; Part of FOLFOX chemotherapy regimen cytotoxic chemotherapy (antimetabolite and pyrimidine analog); Other Names: 5-FU; 5-Fluorouracil; Drug: Oxaliplatin; Part of FOLFOX chemotherapy regimen platinum based compound (alkylating agent); Other Names: Eloxatin; Drug: Leucovorin; Part of FOLFOX chemotherapy regimen (folic acid analog); Other Names: Wellcovorin; Calcium Folinate; Folinic Acid; Drug: Bevacizumab; Monoclonal antibody (VEG-F inhibitor); Other Names: Avastin; Zirabev
Experimental: Part 2 Dose Expansion Cohort 2A; Combination (PF-08032562 + fulvestrant) dose expansion for participants with advanced or metastatic BC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Fulvestrant; Selective Estrogen Receptor Degrader (SERD); Other Names: Faslodex
Experimental: Part 2 Dose Expansion Cohort 2B; PF-08032562 monotherapy or combination (PF-08032562 + cetuximab) dose expansion for participants with advanced or metastatic CRC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Cetuximab; Monoclonal antibody (EGFR inhibitor); Other Names: Erbitux; Enlituo
Experimental: Part 2 Dose Expansion Cohort 2C; Combination (PF-08032562 + [FOLFOX + bevacizumab]) dose expansion for participants with advanced or metastatic CRC, at different doses and/or schedules of the study drug	Drug: PF-08032562; Taken by mouth (PO); Drug: Fluorouracil; Part of FOLFOX chemotherapy regimen cytotoxic chemotherapy (antimetabolite and pyrimidine analog); Other Names: 5-FU; 5-Fluorouracil; Drug: Oxaliplatin; Part of FOLFOX chemotherapy regimen platinum based compound (alkylating agent); Other Names: Eloxatin; Drug: Leucovorin; Part of FOLFOX chemotherapy regimen (folic acid analog); Other Names: Wellcovorin; Calcium Folinate; Folinic Acid; Drug: Bevacizumab; Monoclonal antibody (VEG-F inhibitor); Other Names: Avastin; Zirabev

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1 (Dose Escalation): Number of participants with Dose-Limiting Toxicities (DLT)	Any adverse events that are attributable to one, the other, or both study treatments, occurring in the DLT observation period are considered DLTs, excluding toxicities clearly due to underlying disease or extraneous causes.	Baseline up to 28 days
Part 1 (Dose Escalation): Number of participants with laboratory abnormalities	Number of participants with laboratory test abnormalities.	From start of treatment up to 30 days after last dose or start of new anticancer therapy, whichever occurred first
Part 1 (Dose Escalation): Incidence of Adverse Events (AEs)	An adverse event (AE) was any untoward medical occurrence in a participant who received study medication without regard to possibility of causal relationship to it.	From start of treatment up to 30 days after last dose or start of new anticancer therapy, whichever occurred first
Part 2 (Dose Expansion): Objective Response Rate (ORR)	ORR defined as per Response Evaluation Criteria in Solid Tumors (RECIST v1.1).	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1 & Part 2: Maximum Observed Serum Concentration (Cmax)	Evaluate the single and multiple dose PK of PF-08032562 as monotherapy, or in combination with other anti-tumor agents.	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1 & Part 2: Time to Reach Maximum Observed Serum Concentration (Tmax)	Evaluate the single and multiple dose PK of PF-08032562 as monotherapy, or in combination with other anti-tumor agents.	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1: Area Under the Curve (AUC) from Time Zero to Last Quantifiable Concentration (AUClast)	Evaluate the single and multiple dose PK of PF-08032562 as monotherapy, or in combination with other anti-tumor agents.	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1: Effect of Food on Cmax	Evaluate the effect of food on Cmax of PF-08032562 as monotherapy	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1: Effect of Food on Tmax	Evaluate the effect of food on Tmax of PF-08032562 as monotherapy	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1: Effect of Food on AUClast	Evaluate the effect of food on AUClast of PF-08032562 as monotherapy	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 1: Percent change of immune cells within tumors based on immunohistochemistry assessment	Evaluate the single and multiple dose pharmacodynamics of PF-08032562 as monotherapy, or in combination with other anti-tumor agents. This measure will assess change in the concentration of immune cell-related cytokines and chemokines as potential pharmacodynamic effects of PF-08032562 using Immunohistochemistry (IHC) assays.	Baseline through end of Cycle 1 (each cycle is 28 days)
Part 2 (Dose Expansion): Number of participants with laboratory abnormalities	Number of participants with laboratory test abnormalities.	From start of treatment up to 30 days after last dose or start of new anticancer therapy, whichever occurred first
Part 2 (Dose Expansion): Incidence of Adverse Events (AEs)	An adverse event (AE) was any untoward medical occurrence in a participant who received study medication without regard to possibility of causal relationship to it.	From start of treatment up to 30 days after last dose or start of new anticancer therapy, whichever occurred first
Part 1 & Part 2: Objective Response Rate (ORR) as per Response Evaluation Criteria in Solid Tumors (RECIST v1.1)	ORR is defined as the percentage of participants in the analysis population having a best overall response (BOR) of confirmed complete response (CR) or confirmed partial response (PR) according to RECIST v1.1.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 1 & Part 2: Disease Control Rate (DCR) as per RECIST v1.1	DCR is defined as the proportion of participants with CR or PR with confirmation, or Stable Disease (SD) per RECIST version 1.1.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 1 & Part 2: Clinical Benefit Rate (CBR) as per RECIST v1.1	CBR is defined as the percentage of participants with a best overall response of CR or PR at any time before Progressive Disease (PD), or non-CR/non-PD or SD for at least 24 weeks from start date of treatment and prior to PD, relative to the appropriate analysis set.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 1 & Part 2: Duration of Response (DOR) as per RECIST v1.1	DOR is defined as the time from first documentation of CR or PR to date of first documentation of PD or death due to any cause.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 1 & Part 2: Progression-Free Survival (PFS) as per RECIST v1.1	PFS is defined as time from start date of treatment to the date of first documentation of PD or death due to any cause.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 1 & Part 2: Time to Response (TTR) as per RECIST v1.1	TTR is defined as the time from start date of treatment to first documentation of CR or PR.	Baseline and every 8 to 12 weeks through time of confirmed disease progression, death, unacceptable toxicity, or through study completion (approximately 2 years)
Part 2: Overall Survival (OS)	OS is defined as time from from start date of treatment to the date of death due to any cause	Up to approximately 2 years

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): December 23, 2025
• Primary Completion (Estimated): April 14, 2029
• Study Completion (Estimated): April 14, 2030

Study Registration Dates

• First Submitted: December 4, 2025
• First Submitted That Met QC Criteria: December 19, 2025
• First Posted (Actual): January 6, 2026

Study Record Updates

• Last Update Posted (Actual): July 22, 2026
• Last Update Submitted That Met QC Criteria: July 21, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Triple Negative Breast Cancer; Colon Cancer; Estrogen Receptor Positive Breast Cancer; HER2- Breast Cancer; Carcinoma, Breast
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Colorectal Neoplasms; Colonic Neoplasms; Breast Neoplasms; Triple Negative Breast Neoplasms; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Amino Acids, Peptides, and Proteins; Proteins; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Polycyclic Compounds; Enzymes and Coenzymes; Antibodies, Monoclonal, Humanized; Antibodies, Monoclonal; Antibodies; Immunoglobulins; Immunoproteins; Blood Proteins; Serum Globulins; Globulins; Coordination Complexes; Pyrimidines; Steroids; Fused-Ring Compounds; Formyltetrahydrofolates; Tetrahydrofolates; Folic Acid; Pterins; Pteridines; Uracil; Pyrimidinones; Coenzymes; Estradiol; Estrenes; Estranes; Estradiol Congeners; Gonadal Steroid Hormones; Gonadal Hormones; Oxaliplatin; Fulvestrant; Bevacizumab; Cetuximab; Fluorouracil; Leucovorin
• Other Study ID Numbers: C6321001; 2025-524387-38-00 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No