A Study to Learn How the Body Processes the Study Medicine Called Vepdegestrant in People With Loss of Liver Function

A PHASE 1, NON-RANDOMIZED, OPEN-LABEL, SINGLE-DOSE, PARALLEL GROUP STUDY TO COMPARE THE PHARMACOKINETICS OF VEPDEGESTRANT (PF-07850327) IN ADULT PARTICIPANTS WITH MODERATE AND SEVERE HEPATIC IMPAIRMENT RELATIVE TO HEALTHY PARTICIPANTS WITH NORMAL HEPATIC FUNCTION

The purpose of the study is to look at how the body processes a study medicine called vepdegestrant in participants with loss of liver function relative to people with normal liver function.

This study is seeking participants who are:

• females who cannot have children or males
• between 18 and 70 years of age
• weigh more than 50 Kilograms (110 pounds)
• either healthy with normal liver function or have loss of liver function

All participants in this study will take one dose of vepdegestrant by mouth. This study looks at how the medicine is changed and removed from the body after being taken by the participants. The amount of vepdegestrant in participants with loss of liver function will be compared to the amount of vepdegestrant in participants with normal liver function.

All participants will stay at the study clinic for about 11 days and 10 nights.

Study Overview

• Status: Recruiting
• Conditions: Healthy Participants
• Intervention / Treatment: Drug: vepdegestrant

• Study Type: Interventional
• Enrollment (Estimated): 24
• 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
  • Florida
    • Miami, Florida, United States, 33172
      • Recruiting
      • Clinical Pharmacology of Miami
    • Miami Lakes, Florida, United States, 33016
      • Recruiting
      • Floridian Clinical Research, LLC
    • Orlando, Florida, United States, 32809
      • Recruiting
      • Orlando Clinical Research Center
    • Tampa, Florida, United States, 33603
      • Recruiting
      • Genesis Clinical Research, LLC

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria including but not limited to:

• Female participants of non-childbearing potential, or male participants between the age of 18 years (or the minimum age of consent in accordance with local regulations) and 70 years, inclusive, at screening.
• Body mass index of 17.5-38 kg/m2, inclusive, and a total body weight >50 kg (110 lb).

Normal hepatic function group only:

-Overtly healthy as determined by medical evaluations including medical history, physical examination, laboratory tests, vital signs and standard 12-lead ECGs.

Hepatic impairment groups only:

• Satisfy the criteria for Class B (Group 2: moderate hepatic impairment) or C (Group 3: severe hepatic impairment) of the modified Child-Pugh Classification.
• Stable hepatic impairment, defined as no clinically significant change in disease status within the last 28 days prior to the screening visit, as documented by the participant's recent medical history.

Exclusion criteria including but not limited to:

• Any condition possibly affecting drug absorption.
• Use of prohibited prior or concomitant medications.

Normal hepatic function group only:

-Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing).

Hepatic impairment groups only:

-A diagnosis of hepatic dysfunction secondary to any acute ongoing hepatocellular process that is documented by medical history, PE, liver biopsy, hepatic ultrasound, CT scan, or MRI.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1; participants with normal hepatic function	Drug: vepdegestrant; Vepdegestrant administered as a single oral 200 mg dose; Other Names: ARV-471, PF-07850327
Experimental: Group 2; participants with moderate hepatic impairment	Drug: vepdegestrant; Vepdegestrant administered as a single oral 200 mg dose; Other Names: ARV-471, PF-07850327
Experimental: Group 3; participants with severe hepatic impairment	Drug: vepdegestrant; Vepdegestrant administered as a single oral 200 mg dose; Other Names: ARV-471, PF-07850327

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximum observed concentration (Cmax) for vepdegestrant		Pre-dose, and 1, 2, 4, 6, 8, 12, 24, 36, 48, 60, 72, 96, 120, 144, 168, 192, and 216 hours post dose
Area under the curve from time zero to extrapolated infinite time [AUC (0 - ∞)] for vepdegestrant	AUC (0 - ∞)= Area under the plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (0 - ∞). It is obtained from AUC (0 - t) plus AUC (t - ∞).	Pre-dose, and 1, 2, 4, 6, 8, 12, 24, 36, 48, 60, 72, 96, 120, 144, 168, 192, and 216 hours post dose

Secondary Outcome Measures

Outcome Measure	Time Frame
Number of Participants With Treatment-Emergent Adverse Events	Time from baseline through and including follow-up contact occurring 28 to 35 calendar days after the last administration of the study intervention.
Number of Participants With Clinically Significant Clinical Laboratory Abnormalities	Time from baseline through and including follow-up contact occurring 28 to 35 calendar days after the last administration of the study intervention.
Number of Participants With Clinically Significant Change From Baseline in Vital Signs	Time from baseline through and including follow-up contact occurring 28 to 35 calendar days after the last administration of the study intervention.
Number of Participants With Clinically Significant Electrocardiogram (ECG) Abnormalities	Time from baseline through and including follow-up contact occurring 28 to 35 calendar days after the last administration of the study intervention.

Collaborators and Investigators

• Sponsor: Pfizer
• Collaborators: Arvinas Estrogen Receptor, Inc.
• 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): November 18, 2025
• Primary Completion (Estimated): December 4, 2026
• Study Completion (Estimated): December 23, 2026

Study Registration Dates

• First Submitted: November 13, 2025
• First Submitted That Met QC Criteria: November 13, 2025
• First Posted (Actual): November 17, 2025

Study Record Updates

• Last Update Posted (Actual): April 3, 2026
• Last Update Submitted That Met QC Criteria: March 30, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: C4891004

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