TACTIVE-U: A Study to Learn About the Study Medicine (Called ARV-471) When Given With Other Medicines in People With Advanced or Metastatic Breast Cancer (Sub-Study B)

• Status: Not yet recruiting
• Trial end date: 2027-06-15
• Target enrollment: 0
• Participant gender: All

Summary

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.

We will examine the experiences of people receiving the study medicine. This will help us 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.

• Phase: Phase 1/Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: Pfizer
• Collaborator: Arvinas Estrogen Receptor, Inc.

Criteria

Inclusion Criteria:

• histological or cytological diagnosis of ER+ and HER2- advanced/metastatic breast cancer that is not amendable to surgical resection with curative intent (≥1% ER+ stained cells on the most recent tumor biopsy).

• prior anticancer therapies: up to 2 lines of prior therapies for advanced/metastatic disease; only 1 line of any CDK4/6 inhibitor-based regimen is allowed

• at least 1 measurable lesion as defined by RECIST v1.1.

• ECOG PS ≤1.

Exclusion Criteria:

• visceral crisis at risk of life-threatening complications in the short term

• known history of drug-induced pneumonitis or other significant symptomatic deterioration of lung functions.

• newly diagnosed brain metastases, or symptomatic CNS metastases, carcinomatous meningitis, or leptomeningeal disease. Participants with a history of CNS metastases or cord compression are eligible if they have been definitively treated, clinically stable and discontinued anti-seizure medications and corticosteroids for at least 14 days prior to enrollment in the of study.

• history of any other tumor malignancies within the past 3 years, except for the following: (1) adequately treated basal or squamous cell carcinoma of the skin; (2) curatively treated in situ carcinoma of the cervix.

• inflammatory breast cancer

• impaired cardiovascular function or clinically significant cardiovascular diseases

• concurrent administration of medications, food, or herb supplements that are strong inhibitors and strong/moderate inducers of CYP3A and drugs known to predispose to Torsade de Pointes or QT interval prolongation.

• renal impairment, not adequate liver function and/or bone marrow function

• known active infection