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Vepdegestrant (ARV-471/PF-07850327) + Palbociclib vs Letrozole + Palbociclib in ER(+)/HER2(-) Advanced Breast Cancer

NCT05909397 · Status: ACTIVE_NOT_RECRUITING · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 59

Last updated 2026-02-10

No results posted yet for this study

Summary

The purpose of this study is to understand the safety and effects of the study medicine vepdegestrant (ARV-471/PF-07850327) given together with palbociclib in advanced breast cancer. In particular, the study will compare the combination of vepdegestrant plus palbociclib to standard of care therapy (letrozole plus palbociclib). Both letrozole and palbociclib are medicines already used for treatment of breast cancer. Vepdegestrant is a new medicine under study.

This study is seeking participants who have breast cancer that:

* Have a locally advanced or metastatic disease and cannot be fully cured by surgery or radiation therapy. A metastatic disease is when disease has spread to other parts of the body.
* Is sensitive to hormonal therapy such as tamoxifen. This is called estrogen receptor positive disease.
* Have not received any prior medicine for advanced disease. Example medications include tamoxifen or letrozole or exemestane.

The study will have an open-label SLI (study lead-in) before initiation of Phase 3 trial. During SLI, two dose levels of palbociclib in combination with vepdegestrant will be explored in parallel. Assignment to the palbociclib dose is by chance. Half of the participant will receive one dose and the other half another palbociclib dose. The purpose of SLI is to determine the recommended Phase 3 dose of palbociclib to be administered in combination with vepdegestrant.

In the Phase 3, half of the participants will take vepdegestrant plus palbociclib while the other half will take letrozole plus palbociclib. In both SLI and Phase 3, participants will take the study medicines by mouth, with food, once a day. Participants will take the study medicines until breast cancer increase in size or side effects become too severe. Side effects refer to unwanted reactions to medications. Participants will visit the study clinic about once every 4 weeks.

Conditions

Interventions

DRUG

Vepdegestrant (ARV-471/PF-07850327)

Pharmaceutical form: Tablets. Route of Administration: Oral

COMBINATION_PRODUCT

Palbociclib

Pharmaceutical form: Capsules. Route of Administration: Oral.

DRUG

Letrozole

Pharmaceutical form: Capsules. Route of Administration: Orally

COMBINATION_PRODUCT

Palbociclib

Pharmaceutical form: Capsules. Route of Administration: Oral.

Sponsors & Collaborators

  • Arvinas Estrogen Receptor, Inc.

    collaborator INDUSTRY

  • Pfizer

    lead INDUSTRY

Principal Investigators

  • Pfizer CT.gov Call Center · Pfizer

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2023-08-09
Primary Completion
2026-12-30
Completion
2026-12-30
FDA Drug
Yes

Countries

  • United States
  • Australia
  • Brazil
  • China
  • Hungary
  • Italy
  • Japan
  • Slovakia
  • Spain
  • Switzerland

Study Locations

More Related Trials

Entities

Drugs
Diseases
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05909397 on ClinicalTrials.gov