A Phase 3 interventional study of Adjuvant systemic therapy based on pathological findings and ET response and Adjuvant systemic therapy based on pathological findings in Breast Cancer, sponsored by Tokyo Women's Medical University. Recruiting at 49 sites in Japan. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-08.
Sponsored by Tokyo Women's Medical University · Phase 3, Interventional, and Treatment
Young HOPE/JCOG2402 is a multicenter, randomized phase III study designed to evaluate response-guided therapy following neoadjuvant endocrine therapy to optimize adjuvant treatment in premenopausal HR+/HER2- Breast Cancer.
Premenopausal women with intermediate-risk HR-positive/HER2-negative breast cancer derive benefit from the addition of chemotherapy to endocrine therapy. However, previous studies have demonstrated that patients who achieve an endocrine response (Ki-67 ≤10%) following neoadjuvant endocrine therapy have excellent outcomes without chemotherapy, irrespective of menopausal status. These findings suggest that endocrine therapy response may serve as a predictive biomarker to identify premenopausal patients who can safely omit chemotherapy.
The primary objective of this study is to evaluate the non-inferiority of an ET response-guided treatment strategy compared with standard surgery followed by adjuvant therapy. The study aims to increase the proportion of patients who can be treated with endocrine therapy alone by omitting chemotherapy in those with highly endocrine-sensitive disease.
Eligible patients are randomized 1:1 to upfront surgery or neoadjuvant endocrine therapy with an aromatase inhibitor and ovarian function suppression. The primary endpoint is EFS. Secondary endpoints include overall survival, relapse-free survival, distant recurrrence-free survival, HR-QOL, the rate of endocrine therapy alone in adjuvant therapy, ET response rate in an Arm B, the rate of non-menopause and safety. A total of 950 patients will be enrolled. Randomization is stratified by cN0 vs cN1, HG1 or 2 vs 3, and institution.
The JCOG2402 trial addresses an unmet need in adjuvant therapy of premenopausal HR-positive, HER2-negative breast cancer with intermediate risk and may contribute to the establishment of a new treatment strategy.
12,544 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's planned enrollment of 950 is above the median of 72 across 9,303 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Tokyo Women's Medical University is the lead sponsor of 8 studies on the registry; 3 are open to participants now.
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Exclusion Criteria:
Participants in Arm A will undergo breast surgery and adjuvant systemic treatment.
Drug: Adjuvant systemic therapy based on pathological findings
Participants in Arm B will receive neoadjuvant endocrine therapy of aromatase inhibitor and OFS for three months, followed by breast surgery.
Drug: Adjuvant systemic therapy based on pathological findings and ET response
If patients with Oncotype DX RS between 16-25 (for pN0 patients) and 0-25 (for pN1 patients) have an ET response (Ki-67 ≤10%), they are treated with endocrine therapy plus OFS without chemotherapy. Patients without an ET response or with high risk (RS ≧26) receive chemotherapy and endocrine therapy with OFS. Patients with RS ≤ 15 (pN0) are treated with tamoxifen. Adjuvant chemotherapy for pN0 and pN1 is TC and anthracycline-taxane, respectively. Aromatase inhibitor or tamoxifen is co-administered with a LHRH agonist for 5 years. The choice of AI is per investigator discretion. The choice of LHRH agonist and dosing schedule is per investigator's discretion. Endocrine treatment beyond 5 years is at the investigator's discretion.
Patients with Oncotype DX recurrence score (RS) ≧16 (pN0) or pN1 are treated with chemotherapy and endocrine therapy with ovarian function suppression (OFS). Adjuvant chemotherapy for pN0 and pN1 is TC and anthracycline-taxane, respectively. Aromatase inhibitor or tamoxifen co-administered with a LHRH agonist for 5 years. The choice of AI is per investigator discretion. The choice of LHRH agonist and dosing schedule is per investigator's discretion. Endocrine treatment beyond 5 years is at the investigator's discretion. Patients with RS ≤ 15 are treated with tamoxifen.
Event free survival
Time from randomization to the first diagnosis of local invasive recurrence, regional recurrence, distant recurrence, contralateral invasive breast cancer, inoperable progressive disease during neoadjuvant endocrine therapy, second primary invasive non-breast cancer (excluding non-melanoma skin cancer and in situ cervical cancer), or death from any cause
Time frame: Up to 12 years (5 years of accrual and 7 years of follow-up)
Overall survival
Time from randomization to death from any cause
Time frame: Up to 12 years (5 years of accrual and 7 years of follow-up)
Relapse-free survival
Time from randomization to the first diagnosis of relapse or death from any cause
Time frame: Up to 12 years (5 years of accrual and 7 years of follow-up)
Distant recurrence-free survival
Time from randomization to the first diagnosis of distant recurrence of breast cancer or death from any cause
Time frame: Up to 12 years (5 years of accrual and 7 years of follow-up)
Plan to share: Undecided
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