A Trial Using ARV-471 or Anastrozole in Post-Menopausal Women With Breast Cancer Prior to Surgery

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Status and phase

Active, not recruiting
Phase 2


Breast Cancer


Drug: ARV-471
Drug: Anastrozole
Procedure: Surgical resection of breast tumor

Study type


Funder types



C4891025 (Other Identifier)

Details and patient eligibility


This trial is a Phase 2 neoadjuvant study evaluating ARV-471 or anastrozole in post-menopausal women with ER+/HER2- localized breast cancer.

Full description

This is a Phase 2, open-label, randomized, non-comparative proof of concept study of ARV-471 or anastrozole in participants with ER+/HER2- breast cancer amenable to definitive surgical resection. The main goal of this study is to evaluate the biological activity of ARV-471 and anastrozole, respectively.


152 patients




18+ years old


No Healthy Volunteers

Inclusion criteria

  • Post-menopausal females ≥ 18 years

  • Histologically or cytologically confirmed ER+ and HER2- breast cancer (per local assessment). ER and HER2 status must be documented:

    • ER+ disease, with ER staining of ≥ 10% of tumor cell nuclei by IHC per ASCO/CAP Guidelines (Allison 2020).
    • HER2- disease by either IHC or in situ hybridization per ASCO/CAP guidelines
    • Ki-67 score ≥ 5%, analyzed locally
  • Clinical T1c-T4c, N0-N2, M0 breast cancer amenable to definitive surgical resection, without bilateral breast ductal carcinoma in situ or invasive breast cancer

  • The primary tumor must be at least 1.5 cm by imaging

  • ECOG performance status of 0 or 1 Willingness to undergo a screening biopsy, an on-treatment biopsy and surgical resection

Exclusion criteria

  • Any other active malignancy within 3 years prior to enrollment, except for adequately treated basal cell or squamous cell skin cancer, or cervical carcinoma in situ
  • Any of the following in the previous 6 months: Myocardial infarction; Severe unstable angina; Coronary/peripheral artery bypass graft; Symptomatic congestive heart failure (New York Heart Association class III or IV); Cerebrovascular accident; Transient ischemic attack; Symptomatic pulmonary embolism or other clinically significant episode of thromboembolism
  • Any of the following in the previous 6 months: Congenital long QT syndrome; Torsade de Pointes; Sustained ventricular tachyarrhythmia and ventricular fibrillation; Left anterior hemiblock (bifascicular block); Ongoing cardiac dysrhythmias of NCI CTCAE ≥ Grade 2; Atrial fibrillation of any grade (≥ Grade 2 in the case of asymptomatic lone atrial fibrillation)
  • QTcF > 470 msec
  • Active, uncontrolled bacterial, fungal or viral infection, including HBV, HCV, and HIV or AIDS-related illness
  • Active inflammatory gastrointestinal disease, chronic diarrhea, known uncontrolled diverticular disease, or previous gastric resection or lap band surgery
  • Cirrhosis meeting criteria for Child Pugh B and C
  • Prior treatment for breast cancer including systemic therapy (eg, chemotherapy, hormonal therapy), radiation, surgery, or any investigational agents
  • Any live vaccines within 14 days of planned start of first dose of study drug.
  • Major surgery (as defined by the Investigator) within four weeks of first dose of study drug

Trial design

Primary purpose




Interventional model

Parallel Assignment


None (Open label)

152 participants in 2 patient groups

ARV-471 monotherapy
Experimental group
ARV-471 taken once daily until surgical resection
Procedure: Surgical resection of breast tumor
Drug: ARV-471
Anastrozole monotherapy
Active Comparator group
Anastrozole 1mg taken once daily until surgical resection
Procedure: Surgical resection of breast tumor
Drug: Anastrozole

Trial contacts and locations



Central trial contact

Arvinas Estrogen Receptor, Inc.

Data sourced from

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