BGB-21447 (Bcl-2 Inhibitor) Combinations for Adults With Hormone-Receptor Positive (HR+)/Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Metastatic Breast Cancer

Purpose

This is a dose escalation and dose expansion study to assess the safety and tolerability of BGB-21447 (a B-cell leukemia/lymphoma 2 inhibitor, Bcl-2i) in combination with fulvestrant, with or without BGB-43395 (cyclin-dependent kinase 4 inhibitor, CDK4i), in adults with HR+/HER2- metastatic breast cancer.

Conditions

  • Hormone-receptor-positive Breast Cancer
  • HER2-negative Breast Cancer
  • Metastatic Breast Cancer

Eligibility

Eligible Ages
Over 18 Years
Eligible Sex
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Histologically or cytologically confirmed HR+/HER2- metastatic breast cancer. Part 1A and 1B: Participants must have received ≥ 1 prior line(s) of treatment for advanced/metastatic disease, including prior endocrine therapy and CDK4/6 inhibitor in either the adjuvant or advanced/metastatic setting. Part 2: Participants must have received 1-3 prior line(s) of treatment for advanced/metastatic disease, including prior endocrine therapy and CDK4/6 inhibitor in either the adjuvant or advanced/metastatic setting. - Female participants will be required (either continue ongoing or initiate as soon as feasible) to have ovarian function suppression using gonadotropin-releasing hormone (GnRH) agonists (such as goserelin) or be postmenopausal. - Male participants may be required to use GnRH agonists when being treated with fulvestrant at the discretion of the investigator. - Participants must have a stable Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤ 1. - Adequate organ function. - Female participants of childbearing potential and nonsterile male participants with female partners of childbearing potential must be willing to use a highly effective method of birth control for the duration of the study and for 7 days after the last dose of BGB-21447, 6 months after the last dose of BGB-43395, and 2 years after the last dose of fulvestrant. - Food effect substudy only: Participants who are able and willing to fast overnight (≥ 10 hours) and consume a high-fat meal.

Exclusion Criteria

  • Prior Bcl-2 inhibitor exposure. For triplet combination cohorts only: Prior therapy selectively targeting CDK4. - Known leptomeningeal disease or uncontrolled, untreated brain metastases. - Any malignancy ≤ 3 years before the first dose of study treatment(s) except for the specific cancer under investigation in this study and any locally recurring cancer that has been treated with curative intent (eg, treated papillary thyroid carcinoma, resected basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix or breast). - For Part 1B: Uncontrolled diabetes. - History of hepatitis B or active Hepatitis C infection - China Only: Untreated chronic hepatitis B or chronic hepatitis B virus (HBV) carriers with HBV DNA > 500 IU/ml (or > 2500 copies/ml) at screening. Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Study Design

Phase
Phase 1
Study Type
Interventional
Allocation
Non-Randomized
Intervention Model
Sequential Assignment
Primary Purpose
Treatment
Masking
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Part 1A: BGB-21447 + Fulvestrant
Sequential cohorts of increasing dose levels of BGB-21447 will be evaluated in combination with fulvestrant.
  • Drug: BGB-21447
    Administered orally.
  • Drug: Fulvestrant
    Administered via intramuscular injection.
Experimental
Part 1B: BGB-21447 + BGB-43395 + Fulvestrant
Sequential cohorts of increasing dose levels of BGB-21447 will be evaluated in combination with fulvestrant and BGB-43395.
  • Drug: BGB-21447
    Administered orally.
  • Drug: Fulvestrant
    Administered via intramuscular injection.
  • Drug: BGB-43395
    Administered orally.
Experimental
BGB-21447 + Fulvestrant Food Effect Substudy
Participants will receive BGB-21447 at the recommended dose with a high-fat meal and under a fasted state in combination with fulvestrant.
  • Drug: BGB-21447
    Administered orally.
  • Drug: Fulvestrant
    Administered via intramuscular injection.
Experimental
Part 2: Dose Expansion, BGB-21447 + Fulvestrant
Participants will receive BGB-21447 at the recommended dose(s) for expansion determined in Part 1A in combination with fulvestrant.
  • Drug: BGB-21447
    Administered orally.
  • Drug: Fulvestrant
    Administered via intramuscular injection.

Recruiting Locations

Hoag Memorial Presbyterian
Newport Beach 5376890, California 5332921 92663-4162

University of Iowa Hospitals and Clinics
Iowa City 4862034, Iowa 4862182 52242-1009

Md Anderson Cancer Center
Houston 4699066, Texas 4736286 77030-3907

Fred Hutchinson Cancer Research Center
Seattle 5809844, Washington 5815135 98109-4433

More Details

NCT ID
NCT06756932
Status
Recruiting
Sponsor
BeOne Medicines

Study Contact

Study Director
1.877.828.5568
clinicaltrials@beonemed.com

Detailed Description

This new study will check how safe and helpful a potential anticancer drug called BGB-21447 (Bcl-2i) is. This drug will be tested in combination with fulvestrant, with or without BGB-43395 (CDK4i), in adults with metastatic breast cancer. HR+/HER2- tumors account for approximately 70% of all breast cancers and are responsible for most breast cancer-related deaths. While CDK4/6 inhibitors combined with endocrine therapy have improved outcomes for patients with HR+/HER2- metastatic breast cancer, patients eventually develop progressive disease on these therapies and require new treatments. BGB-21447 is an oral drug that is highly potent and selectively stops a protein called B-cell lymphoma-2 (Bcl-2). Bcl-2 proteins are often overexpressed in some cancers (like HR+ breast cancer) by keeping the cancer cells from dying. Disrupting this pathway is believed to lead to cell death. BGB-43395 is an oral drug that selectively stops a protein called cyclin-dependent kinase 4 (CDK4). CDK4 is a type of protein that regulates cell growth and division in your body. Fulvestrant is a treatment that blocks estrogen receptors and reduces estrogen production. Fulvestrant has been approved to treat hormone receptor positive metastatic breast cancer to help stop the cancer cells from growing. This combination might be a good way to fight cancer, aiming to give patients the best possible treatment. The study is designed to see if this combination is safe and works well.