A Study of Elacestrant Versus Standard Endocrine Therapy in Women and Men With ER+,HER2-, Early Breast Cancer With High Risk of Recurrence (ELEGANT)

Stemline Therapeutics

Status and phase: Enrolling; Phase 3

Conditions: Breast Cancer

Treatments: Drug: Elacestrant; Drug: Tamoxifen; Drug: Exemestane; Drug: Letrozole; Drug: Anastrozole

Study type: Interventional

Funder types: Industry

Identifiers

NCT06492616

2024-515445-42-00 (EU Trial (CTIS) Number)

STML-ELA-0422

Details and patient eligibility

About

The primary goal of this study is to evaluate the effectiveness of elacestrant versus standard endocrine therapy in participants with node-positive, Estrogen Receptor-positive (ER+), Human Epidermal Growth Factor-2 negative (HER2-) early breast cancer with high risk of recurrence.

Enrollment: 4,220 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

Key Inclusion Criteria:

• Histopathologically or cytologically confirmed ER+ (≥10% by immunohistochemistry [IHC]), HER2- (tumors with an IHC score of 0, 1+, or 2+ with in situ hybridization [ISH]-negative [not amplified]). ISH-negative without IHC testing will also be eligible on tumor biopsy or final surgical pathology specimen early stage resected invasive breast cancer without evidence of recurrence or distant metastases, per local laboratory, according to the American Society of Clinical Oncology/College of American Pathologists guidelines.

• Participants must be node positive (microscopic and macroscopic tumor involvement are allowed) and fulfill one of the following criteria:

  1. ≥4 positive axillary lymph nodes or

  2. 1-3 positive axillary lymph nodes and

     1. Histologic grade 3 disease and/or
     2. Tumor size ≥5 centimeters and/or
     3. High genomic risk (identified by Oncotype, MammaPrint, EndoPredict, PAM50)

• Participants who are currently taking endocrine therapy (aromatase inhibitors or tamoxifen) and have received at least 24 months but not more than 60 months of endocrine therapy at the time of randomization (Cycle 1 Day 1 [C1D1]) with or without a CDK 4 and CKD 6 inhibitor (CDK4/6i) and with or without a luteinizing hormone-releasing hormone agonist.

• Participants who received prior CDK4/6i or a poly adenosine diphosphate-ribose polymerase inhibitor must have already completed or discontinued these treatments.

Key Exclusion Criteria:

• Participants with inflammatory breast cancer.
• History of any prior (ipsilateral and/or contralateral) invasive breast cancer.
• Participant with history of non-breast malignancy within 3 years of the date of randomization, except for adequately treated basal or squamous cell skin cancer, superficial bladder cancer or carcinoma in situ of the cervix.
• Participants who have had more than a 6-month continuous interruption of prior SoC adjuvant endocrine therapy or who are off current adjuvant endocrine therapy more than 6 months prior to randomization.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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4,220 participants in 2 patient groups

Elacestrant

Experimental group

Description:

Participants will receive 345 milligrams (mg) elacestrant once daily (QD) for 5 years.

Treatment:

Drug: Elacestrant

Standard of Care (SoC) Endocrine Therapy

Experimental group

Description:

Participants will receive the SoC endocrine therapy that was used prior to randomization: * AI (anastrozole 1 mg QD, letrozole 2.5 mg QD, or exemestane 25 mg QD); or * Tamoxifen 20 mg QD

Treatment:

Drug: Anastrozole

Drug: Letrozole

Drug: Exemestane

Drug: Tamoxifen