NCT06756932 · BeOne Medicines
BGB-21447 (Bcl-2 Inhibitor) Combinations for Adults With Hormone-Receptor Positive (HR+)/Human Epidermal Growth Factor Receptor 2 Negative (HER2-) Metastatic Breast Cancer
What this study is about
This is a gradually increasing doses and dose expansion study to assess the safety and how well patients handle the treatment 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.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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.
Where
- Iowa City, Iowa
- Houston, Texas
- Seattle, Washington
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jun 22, 2026 · Source of record for eligibility and locations