Ribociclib plus anastrozole for HR-positive, HER2-negative metastatic breast cancer

Phase Ib/II Trial of Ribociclib Plus Anastrozole in Patients With Hormone Receptor-Positive, HER2-Negative Metastatic or Recurrent Breast Cancer

This trial will test whether adding ribociclib to anastrozole helps people in Japan with HR-positive, HER2-negative metastatic or recurrent breast cancer.

Quick facts

• Phase: Phase1; Phase2
• Study type: Interventional
• Enrollment: 86 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Nagoya City University (Academic / other)
• Drugs / interventions: chemotherapy
• Locations: 1 site (Nagoya)
• Trial ID: NCT07164976 on ClinicalTrials.gov

What this trial studies

This Phase Ib/II trial in Japan combines the CDK4/6 inhibitor ribociclib with the aromatase inhibitor anastrozole for patients with HR-positive, HER2-negative metastatic or recurrent breast cancer. Phase Ib evaluates tolerability and dose-limiting toxicities and collects pharmacokinetic data across ribociclib 400 mg and 600 mg dose cohorts. Phase II measures overall response rate determined by blinded central imaging review using RECIST criteria to estimate anti-tumor activity. Safety, adverse events, and serious adverse events are monitored throughout the study.

Who should consider this trial

Good fit: Adults (≥18) in Japan with histologically confirmed HR-positive, HER2-negative unresectable recurrent or metastatic breast cancer, ECOG 0–1, suitable for endocrine therapy, and without prior CDK4/6 inhibitor or metastatic systemic therapy exposure.

Not a fit: Patients with symptomatic visceral metastases, those unsuitable for endocrine therapy, those previously treated with CDK4/6 inhibitors, or with recent adjuvant endocrine therapy are unlikely to benefit from joining this trial.

Why it matters

Potential benefit: If successful, the combination could improve tumor responses and extend the time patients can be treated with endocrine-based therapy before needing chemotherapy.

How similar studies have performed: Large international trials combining ribociclib with aromatase inhibitors have shown improved progression-free survival, so the approach is established though this trial focuses on dose, tolerability, and response in Japanese patients.

Eligibility criteria

Inclusion Criteria:

* Histologically confirmed invasive breast cancer.
* Hormone receptor-positive (ER positive and/or PgR positive) and HER2-negative disease:

ER positive: ≥1% positive cells or Allred score ≥3.

PgR positive: ≥1% positive cells or Allred score ≥3.

HER2 negative: IHC 0, 1+, or 2+ with no ISH amplification.

* Advanced or recurrent breast cancer (unresectable, recurrent, or Stage IV).
* Age ≥18 years at registration.
* ECOG Performance Status of 0-1.

Exclusion Criteria:

* Symptomatic visceral metastases or deemed unsuitable for endocrine therapy.
* Prior endocrine therapy or chemotherapy for metastatic/recurrent disease.
* Prior CDK4/6 inhibitor exposure (perioperative or metastatic setting).
* Adjuvant endocrine therapy within 35 days before study start.
* Active malignancy other than allowed exceptions (e.g., resected skin cancers, ≥5-year disease-free cancers).
* Hypersensitivity to ribociclib, anastrozole, or their components (including soy/peanut allergy, sugar intolerances).

Where this trial is running

Nagoya

• Nagoya City University — Nagoya, Japan (Recruiting)

Study contacts

• Study coordinator: Kazuki Nozawa

Conditions Breast Cancer; breast cancer; ribociclib