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

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-Ki-67 from C1D15/Ki-67 from baseline).

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).

<p>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 Statistical Analysis Plan (SAP).
The number of participants with the following disease staging at post-surgery are summarized:</p><p>Pathologic Tumor - ypT (ypTx, ypT0, ypTis, ypT1mi, ypT1a, ypT1b, ypT1c, ypT2, ypT3, ypT4a, ypT4b, ypT4c) Pathological Lymph Nodes - ypN (ypNX, ypN0, ypN0[i+], ypN0[mol+], ypN1, ypN1mi, ypN1a, ypN1b, ypN1c, ypN2, ypN2a, ypN2b, ypN3, ypN3a, ypN3b, ypN3c).</p>

<p>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:</p><ul><li>Pathologic Tumor - post-neoadjuvant therapy pathologic tumor categorization (ypT): (ypTx, ypT0, ypTis, ypT1mi, ypT1a, ypT1b, ypT1c, ypT2, ypT3, ypT4a, ypT4b, ypT4c).</li><li>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).</li><li>ypT0 &#x2F; 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&#x2F;ypNX indicates non-measurable disease.</li></ul>

mPEPI score was derived from factors assigned a numerical score following Neoadjuvant endocrine treatment (NET).
Total mPEPI score assigned to each patient was the sum of the risk points derived from the pathological (pT) stage, lymph node (pN) stage and Ki67 level.
Number of participants with score 0 was reported.
Participants with mPEPI score of 0 have pathological stage pT1 or pT2, negative lymph nodes pN0 and proliferation index [Ki-67] of less than or equal to 2.7%.

<p>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.</p><p>mPEPI score of 0 indicates Pathological tumor size T1-T2, no lymph nodes and Ki67 level of 0%-2.7%, 1 indicates: Ki67 level &gt;2.7%-7.3%, 2 indicates Ki67 level &gt;19.7%-53.1% and 3 indicates: tumor sizeT3-T4, presence of lymph nodes and Ki67 level &gt;53.1%.</p>

From first study drug administration up to approximately 6.5 months.

Adverse Events: From first study drug administration up to approximately 6.5 months. All-cause mortality: From randomization up to approximately 6.5 months.

Safety Analysis Set consisting of all enrolled participants who received at least 1 dose of study intervention.
For All-Cause Mortality, Full Analysis Set was used which included all the enrolled participants who were randomized.

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.

2025-07

2025-08

2025-07-04

2025-08-12

2025-07-24

2025-08-29

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-Ki-67 from C1D15/Ki-67 from baseline).

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).

<p>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 Statistical Analysis Plan (SAP).
The number of participants with the following disease staging at post-surgery are summarized:</p><p>Pathologic Tumor - ypT (ypTx, ypT0, ypTis, ypT1mi, ypT1a, ypT1b, ypT1c, ypT2, ypT3, ypT4a, ypT4b, ypT4c) Pathological Lymph Nodes - ypN (ypNX, ypN0, ypN0[i+], ypN0[mol+], ypN1, ypN1mi, ypN1a, ypN1b, ypN1c, ypN2, ypN2a, ypN2b, ypN3, ypN3a, ypN3b, ypN3c).</p>

<p>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:</p><ul><li>Pathologic Tumor - post-neoadjuvant therapy pathologic tumor categorization (ypT): (ypTx, ypT0, ypTis, ypT1mi, ypT1a, ypT1b, ypT1c, ypT2, ypT3, ypT4a, ypT4b, ypT4c).</li><li>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).</li><li>ypT0 &#x2F; 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&#x2F;ypNX indicates non-measurable disease.</li></ul>

mPEPI score was derived from factors assigned a numerical score following Neoadjuvant endocrine treatment (NET).
Total mPEPI score assigned to each patient was the sum of the risk points derived from the pathological (pT) stage, lymph node (pN) stage and Ki67 level.
Number of participants with score 0 was reported.
Participants with mPEPI score of 0 have pathological stage pT1 or pT2, negative lymph nodes pN0 and proliferation index [Ki-67] of less than or equal to 2.7%.

<p>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.</p><p>mPEPI score of 0 indicates Pathological tumor size T1-T2, no lymph nodes and Ki67 level of 0%-2.7%, 1 indicates: Ki67 level &gt;2.7%-7.3%, 2 indicates Ki67 level &gt;19.7%-53.1% and 3 indicates: tumor sizeT3-T4, presence of lymph nodes and Ki67 level &gt;53.1%.</p>