Phase 2
N=152
A Trial Using ARV-471 or Anastrozole in Post-Menopausal Women With Breast Cancer Prior to Surgery
Breast Cancer
Bottom Line
View on ClinicalTrials.gov: NCT05549505 ↗Enrolled (actual)
152
Serious AEs
6.0%
Results posted
Aug 2025
Primary outcome: Primary: Percent Reduction in Ki-67 Expression From Baseline to Day 15 in Tumor Biopsies — 71.4; 72.9 Percent reduction
Study Design & Population
- Study type
- Interventional
- Phase
- Phase 2
- Interventions
- ARV-471 (Drug); Anastrozole (Drug); Surgical resection of breast tumor (Procedure)
- Age
- Adult, Older Adult · 18+ yrs
- Sex
- Female
- Sponsor
- Arvinas Inc.
- Primary completion
- Jul 2024
Outcome Measures
| Outcome | Result | p-value |
|---|---|---|
| PRIMARY Percent Reduction in Ki-67 Expression From Baseline to Day 15 in Tumor Biopsies |
71.4; 72.9 | — |
| SECONDARY Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and TEAEs Leading to Study Drug Discontinuation |
82; 37; 4; 5; 3; 4 | — |
| SECONDARY Pathologic Stage at the Time of Surgical Resection |
0; 0; 1; 0; 1; 0 | — |
| SECONDARY Pathological Complete Response(pCR) Rate at the Time of Surgical Resection |
1; 0 | — |
| SECONDARY Number of Participants With Modified Preoperative Endocrine Prognostic Index (mPEPI) Score of 0 at the Time of Surgical Resection |
21; 10 | — |
| SECONDARY Breast Conserving Surgery (BCS) Rate |
69.6; 54.0 | — |
| SECONDARY Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 |
5; 4; 37; 17; 38; 16 | — |
| SECONDARY Percentage Change From Baseline at Cycle 6 Day 1 in Caliper Measurement of the Primary Tumor |
-32.35; -42.88 | — |
Summary
This trial is a Phase 2 neoadjuvant study evaluating ARV-471 or anastrozole in post-menopausal women with estrogen receptor positive/ human epidermal growth factor receptor 2 (ER+/HER2)- localized breast cancer.
Eligibility Criteria
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 immunohistochemistry (IHC) per American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines.
- 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.
- Eastern Cooperative Oncology Group (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).
- corrected QT (Fridericia method) (QTcF) > 470 msec.
- Active, uncontrolled bacterial, fungal or viral infection, including (but not limited to) hepatitis B virus (HBV), hepatitis C virus (HCV), and known human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (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.
Data sourced from ClinicalTrials.gov (NCT05549505). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.