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Active, not recruiting Phase 1Phase 2 Interventional

TACTIVE-U: A Study to Learn About the Study Medicine (Vepdegestrant) When Given With Other Medicines in People With Advanced or Metastatic Breast Cancer (Sub-Study B)

ClinicalTrials.gov ID: NCT05573555

Public ClinicalTrials.gov record NCT05573555. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

ClinicalTrials.gov public records Last synced Sep 24, 2026, 7:38 PM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

TACTIVE-U: AN INTERVENTIONAL SAFETY AND EFFICACY PHASE 1B/2, OPEN-LABEL UMBRELLA STUDY TO INVESTIGATE TOLERABILITY, PK, AND ANTITUMOR ACTIVITY OF VEPDEGESTRANT (ARV-471/PF-07850327), AN ORAL PROTEOLYSIS TARGETING CHIMERA, IN COMBINATION WITH OTHER ANTICANCER TREATMENTS IN PARTICIPANTS AGED 18 YEARS AND OVER WITH ER+ ADVANCED OR METASTATIC BREAST CANCER, SUB-STUDY B (ARV-471 IN COMBINATION WITH RIBOCICLIB)

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called ARV-471) when given together with other medicines for the potential treatment of advanced or metastatic breast cancer. This study is seeking participants who have breast cancer that: * is advanced, may have spread to other organs (metastatic) and cannot be fully treated by surgery or radiation therapy * is sensitive to hormonal therapy (it is called estrogen receptor positive); and * is no longer responding to previous treatments This study is divided into separate sub-studies. For Sub-Study B: All participants will receive ARV-471 and a medicine called ribociclib. ARV-471 and ribociclib will be given at the same time by mouth, at home, 1 time a day. The experiences of people receiving the study medicine will be examined. This will help determine if the study medicine is safe and effective. Participants will continue to take ARV-471 and ribociclib until their cancer is no longer responding, or side effects become too severe. They will have visits at the study clinic about every 4 weeks.

Study identification

NCT ID
NCT05573555
Recruitment status
Active, not recruiting
Study type
Interventional
Phase
Phase 1, Phase 2
Lead sponsor
Pfizer
Industry
Enrollment
20 participants

Conditions and interventions

Conditions

Interventions

Drug

Eligibility (public fields only)

Age range
18 Years and older
Sex
All
Healthy volunteers
Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date
Feb 28, 2023
Primary completion
Dec 29, 2026
Completion
Dec 29, 2026
Last update posted
Mar 8, 2026

2023 – 2026

United States locations

U.S. sites
20
U.S. states
5
U.S. cities
10
Facility City State ZIP Site status
Stanford Women's Cancer Center Palo Alto California 94304 —
UCSF Medical Center at Mission Bay San Francisco California 94158 —
Moffitt Cancer Center - International Plaza Tampa Florida 33607 —
Moffitt Cancer Center, Richard M. Shulze Family Foundation Outpatient Center Tampa Florida 33612 —
Moffitt Cancer Center Tampa Florida 33612 —
Moffitt McKinley Hospital Tampa Florida 33612 —
Siteman Cancer Center - WUPI Shiloh Illinois 62269 —
Brigham and Women's Hospital Boston Massachusetts 02115 —
Dana-Farber Cancer Institute Boston Massachusetts 02215 —
Dana-Farber Cancer Institute - Chestnut Hill Newton Massachusetts 02459 —
Siteman Cancer Center - St Peters City of Saint Peters Missouri 63376 —
Siteman Cancer Center - West County Creve Coeur Missouri 63141 —
Siteman Cancer Center - North County Florissant Missouri 63031 —
Siteman Cancer Center St Louis Missouri 63108 —
Barnes Jewish Hospital Department of Laboratories St Louis Missouri 63110 —
Barnes-Jewish Hospital St Louis Missouri 63110 —
Washington University School of Medicine - Siteman Cancer Center St Louis Missouri 63110 —
Washington University School of Medicine St Louis Missouri 63110 —
Barnes Jewish Hospital Lab- South County St Louis Missouri 63129 —
Siteman Cancer Center - South County St Louis Missouri 63129 —

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

Non-U.S. locations

This page focuses on the U.S. directory. The official record also lists 9 non-U.S. sites.

About this trial record page

What this page shows
Public field values for ClinicalTrials.gov record NCT05573555, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do
No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from
Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh
Last update posted Mar 8, 2026 · Synced Sep 24, 2026

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Open the official record

The complete protocol, eligibility criteria, and contact information for NCT05573555 live on ClinicalTrials.gov.

View official ClinicalTrials.gov record →