Trial Outcomes & Findings for A Trial Using ARV-471 or Anastrozole in Post-Menopausal Women With Breast Cancer Prior to Surgery (NCT NCT05549505)

Last Updated: 2025-08-29

Results Overview

Tumor biopsy Ki-67 expression (% of tumor cells that are positive for Ki-67) at baseline and Cycle 1 Day 15 (C1D15) was collected. Ki-67 expression was assessed by immunohistochemical staining in a central laboratory. The log-transformed Ki-67 after approximately 2 weeks of treatment as a percentage of the baseline value, ie, the ratio between the Ki-67 measurements obtained from C1D15 visit and baseline was modelled using a generalized linear model (GLM) with both stratification factors (ie, baseline Ki-67 score and the tumor size) and treatment as co-variates. The treatment effects were back transformed into geometric means and their Confidence Intervals. The percent change, in other words, relative reduction, of Ki-67 after 2 weeks of treatment is reported as the complement of the ratio between the Ki-67 measurement from C1D15 and baseline, that is 100% × (1 - geometric mean ratio between Ki-67 at C1D15 and Ki-67 at baseline).

Recruitment status

COMPLETED

Study phase

PHASE2

Target enrollment

152 participants

Primary outcome timeframe

Baseline (during screening, prior to Day 1) and Day 15

Results posted on

2025-08-29

Participant Flow

A total of 152 participants were enrolled.

Participant milestones

Participant milestones
Measure	Arm A: ARV-471 (Experimental) Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than Cycle 6 Day 18 \[C6D18\] + 14 days).	Arm B: Anastrozole Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Overall Study STARTED	102	50
Overall Study Treated	101	48
Overall Study COMPLETED	94	41
Overall Study NOT COMPLETED	8	9

Reasons for withdrawal

Reasons for withdrawal
Measure	Arm A: ARV-471 (Experimental) Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than Cycle 6 Day 18 \[C6D18\] + 14 days).	Arm B: Anastrozole Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Overall Study Lost to Follow-up	2	0
Overall Study Withdrawal by Subject	3	3
Overall Study Other: Miscellaneous	3	6

Baseline Characteristics

Only participants with evaluable central Ki-67 results included in the analysis.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Total n=152 Participants Total of all reporting groups
Age, Continuous	67.4 years STANDARD_DEVIATION 9.23 • n=102 Participants	66.8 years STANDARD_DEVIATION 8.31 • n=50 Participants	67.2 years STANDARD_DEVIATION 8.91 • n=152 Participants
Sex: Female, Male Female	102 Participants n=102 Participants	50 Participants n=50 Participants	152 Participants n=152 Participants
Sex: Female, Male Male	0 Participants n=102 Participants	0 Participants n=50 Participants	0 Participants n=152 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	38 Participants n=102 Participants	23 Participants n=50 Participants	61 Participants n=152 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	59 Participants n=102 Participants	25 Participants n=50 Participants	84 Participants n=152 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	5 Participants n=102 Participants	2 Participants n=50 Participants	7 Participants n=152 Participants
Race/Ethnicity, Customized American Indian or Alaska Native	1 Participants n=102 Participants	0 Participants n=50 Participants	1 Participants n=152 Participants
Race/Ethnicity, Customized Asian	0 Participants n=102 Participants	1 Participants n=50 Participants	1 Participants n=152 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	0 Participants n=102 Participants	0 Participants n=50 Participants	0 Participants n=152 Participants
Race/Ethnicity, Customized Black or African American	1 Participants n=102 Participants	2 Participants n=50 Participants	3 Participants n=152 Participants
Race/Ethnicity, Customized White	98 Participants n=102 Participants	46 Participants n=50 Participants	144 Participants n=152 Participants
Race/Ethnicity, Customized Other	0 Participants n=102 Participants	1 Participants n=50 Participants	1 Participants n=152 Participants
Race/Ethnicity, Customized Unknown or Not Reported	2 Participants n=102 Participants	0 Participants n=50 Participants	2 Participants n=152 Participants
Percentage of Tumor Cells Positive for Ki -67	20.6 Percentage of tumor cells with Ki67 STANDARD_DEVIATION 14.01 • n=100 Participants • Only participants with evaluable central Ki-67 results included in the analysis.	20.1 Percentage of tumor cells with Ki67 STANDARD_DEVIATION 12.25 • n=48 Participants • Only participants with evaluable central Ki-67 results included in the analysis.	20.4 Percentage of tumor cells with Ki67 STANDARD_DEVIATION 13.42 • n=148 Participants • Only participants with evaluable central Ki-67 results included in the analysis.

PRIMARY outcome

Timeframe: Baseline (during screening, prior to Day 1) and Day 15

Population: Ki-67 Evaluable Set included all enrolled participants who were randomized and received at least one dose of study treatment and had evaluable central Ki-67 measurements other than '0' or '\< 1' from baseline and evaluable Ki-67 measurements from C1D15 visits.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=93 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=46 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Percent Reduction in Ki-67 Expression From Baseline to Day 15 in Tumor Biopsies	71.4 Percent reduction Interval 60.6 to 79.3	72.9 Percent reduction Interval 57.8 to 82.6

SECONDARY outcome

Timeframe: From signing of consent to minimum of 30 days after last administration of study drug (up to approximately 6.5 months)

Population: Safety Analysis Set which consisted of all enrolled participants who received at least 1 dose of study intervention.

An AE is any untoward medical occurrence in a participant or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study intervention. A serious adverse event (SAE) was an AE that resulted in any of the following outcomes: death; life threatening; persistent/significant disability/incapacity; initial or prolonged inpatient hospitalization; congenital anomaly/birth defect or was otherwise considered medically important. A TEAE is an AE that emerges or worsens on/after the first dose of ARV-471/Anastrozole to 30 days after the last administration of the study intervention (ie, study drug treatment or surgical resection, whichever occurs last).

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=101 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=48 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and TEAEs Leading to Study Drug Discontinuation TEAEs	82 Participants	37 Participants
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and TEAEs Leading to Study Drug Discontinuation Serious TEAEs	4 Participants	5 Participants
Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious TEAEs and TEAEs Leading to Study Drug Discontinuation TEAEs leading to study drug discontinuation	3 Participants	4 Participants

SECONDARY outcome

Timeframe: At Cycle 6 Day 18 (approximately 5.5 months), each cycle is 28 days

Population: Full Analysis Set included all the enrolled participants who were randomized.

Local pathological assessment of the tissue from surgical resection (performed after approximately 5.5 months of treatment), at minimum, included pathologic stage (ypT and ypN stage) as described in the Laboratory Manual. Participants were analysed based on the current American Joint Committee on Cancer (AJCC) staging system as follows: * Pathologic Tumor - post-neoadjuvant therapy pathologic tumor categorization (ypT): (ypTx, ypT0, ypTis, ypT1mi, ypT1a, ypT1b, ypT1c, ypT2, ypT3, ypT4a, ypT4b, ypT4c). * Pathological Lymph Nodes - post-neoadjuvant therapy pathologic node categorization (ypN): (ypNX, ypN0, ypN0(i+), ypN0(mol+), ypN1, ypN1mi, ypN1a, ypN1b, ypN1c, ypN2, ypN2a, ypN2b, ypN3, ypN3a, ypN3b, ypN3c). * ypT0 / ypN0 indicates no evidence of disease and the progressive grades indicate increasing size of tumor and increasing area of lymph node involvement respectively and ypTx/ypNX indicates non-measurable disease.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN2b	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN3	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN3a	3 Participants	1 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN3b	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN3c	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes Not evaluable	12 Participants	10 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypTx	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT0	1 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypTis	1 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN1c	1 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT1mi	1 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT1a	6 Participants	1 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT1b	7 Participants	2 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT1c	36 Participants	14 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT2	33 Participants	21 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT3	4 Participants	2 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT4a	1 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT4b	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor ypT4c	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathologic Tumor Not Evaluable	12 Participants	10 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypNX	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN0	51 Participants	20 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN0(i+)	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN1	5 Participants	4 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN0(mol+)	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN1mi	4 Participants	3 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN1a	21 Participants	6 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN1b	0 Participants	0 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN2	2 Participants	2 Participants
Pathologic Stage at the Time of Surgical Resection Pathological Lymph Nodes ypN2a	3 Participants	4 Participants

SECONDARY outcome

Timeframe: At Cycle 6 Day 18 (approximately 5.5 months), each cycle is 28 days

Population: Full Analysis set included all the enrolled participants who were randomized.

pCR is defined as no invasive cancer in the breast and sampled axillary lymph nodes following completion of neoadjuvant systemic therapy (ie, Pathologic Tumor - ypT = ypT0 or ypTis, and Pathologic Lymph Nodes - ypN = ypN0 in the current American Joint Committee on Cancer (AJCC) staging system). pCR rate is the percentage of participants with pCR.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Pathological Complete Response(pCR) Rate at the Time of Surgical Resection	1 percentage of participants	0 percentage of participants

SECONDARY outcome

Timeframe: At Cycle 6 Day 18 (approximately 5.5 months), each cycle is 28 days

Population: Full Analysis Set included all the enrolled participants who were randomized.

Modified Pre-operative Endocrine Prognostic Index (mPEPI) score is an investigational prognostic tool used to predict the risk of breast cancer recurrence. It will be derived from factors assigned a numerical score following Neoadjuvant endocrine treatment (NET). The factors include pathologic tumor size, and lymph node status and Ki67 expression in the surgical specimen. Total mPEPI score (mPEPI\_T) per participant is the sum of mPEPI score of each factor. mPEPI score of 0 indicates Pathological tumor size T1-T2, no lymph nodes and Ki67 level of 0%-2.7%, 1 indicates: Ki67 level \>2.7%-7.3%, 2 indicates Ki67 level \>19.7%-53.1% and 3 indicates: tumor sizeT3-T4, presence of lymph nodes and Ki67 level \>53.1%.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Number of Participants With Modified Preoperative Endocrine Prognostic Index (mPEPI) Score of 0 at the Time of Surgical Resection	21 Participants	10 Participants

SECONDARY outcome

Timeframe: At Cycle 6 (from Day 141 to Day 168), each cycle is 28 days

Population: Full Analysis Set included all the enrolled participants who were randomized.

Breast conserving surgery (BCS) Rate is the percentage of participants received breast conserving surgery.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Breast Conserving Surgery (BCS) Rate	69.6 Percentage of participants Interval 60.1 to 77.7	54.0 Percentage of participants Interval 40.4 to 67.0

SECONDARY outcome

Timeframe: At Cycle 6 (from Day 141 to Day 168), each cycle is 28 days

Population: Full Analysis Set included all the enrolled participants who were randomized.

The number of participants with Complete Response (CR), Partial Response (PR), Stable Disease (SD), Progressive Disease (PD), Not Evaluable (NE) per mRECIST calculated. CR = disappearance of all target lesions, PR is \>=30% decrease in sum of diameters of target lesions, progressive disease (PD) is \>=20% increase in sum of diameters of target lesions, stable disease (SD) is \<30% decrease or \<20% increase in sum of diameters of target lesions.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=102 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=50 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 CR	5 Participants	4 Participants
Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 PR	37 Participants	17 Participants
Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 Stable Disease	38 Participants	16 Participants
Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 Progressive disease	3 Participants	1 Participants
Radiographic Response Per Modified Response Evaluation Criteria in Solid Tumors (mRECIST) in Primary Tumor During Cycle 6 NE	19 Participants	12 Participants

SECONDARY outcome

Timeframe: Baseline (Day 1) and Cycle 6 Day 1 (At Day 141), each cycle is 28 days

Population: Full Analysis Set included all the enrolled participants who were randomized. Here "Overall Number of Participants Analyzed" signifies those participants who were evaluable for this outcome measure.

The percentage change from the baseline of the primary breast tumor size in physical exam calculated in caliper measurement. Caliper-based response is the maximum percentage decrease or minimum percentage increase if there is no decrease per participant.

Outcome measures

Outcome measures
Measure	Arm A: ARV-471 (Experimental) n=45 Participants Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=19 Participants Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Percentage Change From Baseline at Cycle 6 Day 1 in Caliper Measurement of the Primary Tumor	-32.35 Percent change Standard Deviation 23.739	-42.88 Percent change Standard Deviation 18.041

Adverse Events

Arm A: ARV-471 (Experimental)

Serious events: 4 serious events

Other events: 72 other events

Deaths: 0 deaths

Arm B: Anastrozole

Serious events: 5 serious events

Other events: 32 other events

Deaths: 0 deaths

Serious adverse events

Serious adverse events
Measure	Arm A: ARV-471 (Experimental) n=101 participants at risk Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=48 participants at risk Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Cardiac disorders Angina pectoris	0.00% 0/101 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Cardiac disorders Cardiac arrest	0.00% 0/101 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Bacteraemia	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations COVID-19	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Post procedural infection	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Postoperative wound infection	0.00% 0/101 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Pyelonephritis	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Injury, poisoning and procedural complications Post procedural haematoma	0.00% 0/101 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Nervous system disorders Ataxia	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Nervous system disorders Encephalopathy	0.00% 0/101 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Psychiatric disorders Mental status change	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.

Other adverse events

Additional Information

Arvinas Estrogen Receptor, Inc.

Arvinas Estrogen Receptor, Inc

Phone: 475-345-3366

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	Arm A: ARV-471 (Experimental) n=101 participants at risk Participants received 200 mg ARV-471 (2\*100 mg tablets) once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).	Arm B: Anastrozole n=48 participants at risk Participants received 1 mg Anastrozole tablet orally once daily for approximately 5.5 months prior to undergoing surgical resection (no later than C6D18 + 14 days).
Blood and lymphatic system disorders Anaemia	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Ear and labyrinth disorders Vertigo	6.9% 7/101 • Number of events 7 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	4.2% 2/48 • Number of events 2 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Gastrointestinal disorders Constipation	15.8% 16/101 • Number of events 19 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Gastrointestinal disorders Nausea	14.9% 15/101 • Number of events 16 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 2 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
General disorders Asthenia	20.8% 21/101 • Number of events 24 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	10.4% 5/48 • Number of events 5 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
General disorders Fatigue	12.9% 13/101 • Number of events 14 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations COVID-19	5.9% 6/101 • Number of events 6 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Nasopharyngitis	4.0% 4/101 • Number of events 4 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Infections and infestations Urinary tract infection	7.9% 8/101 • Number of events 10 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Investigations Alanine aminotransferase increased	5.9% 6/101 • Number of events 6 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Metabolism and nutrition disorders Decreased appetite	7.9% 8/101 • Number of events 10 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	0.00% 0/48 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Musculoskeletal and connective tissue disorders Arthralgia	13.9% 14/101 • Number of events 16 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	31.2% 15/48 • Number of events 15 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Nervous system disorders Dizziness	5.0% 5/101 • Number of events 5 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Nervous system disorders Headache	7.9% 8/101 • Number of events 10 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Psychiatric disorders Insomnia	8.9% 9/101 • Number of events 10 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	2.1% 1/48 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Skin and subcutaneous tissue disorders Alopecia	0.99% 1/101 • Number of events 1 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	6.2% 3/48 • Number of events 3 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Vascular disorders Hot flush	24.8% 25/101 • Number of events 28 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	20.8% 10/48 • Number of events 10 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.
Vascular disorders Hypertension	11.9% 12/101 • Number of events 18 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.	8.3% 4/48 • Number of events 4 • Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months. Adverse events were collected for the Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention. For All-Cause Mortality, events were collected from the Full Analysis Set, which included all the enrolled participants who were randomized.