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RecruitingPhase 1

BGB-43395 Alone or as Part of Combination Therapies in Participants With Breast Cancer and Other Advanced Solid Tumors

A Phase 1a/1b Study Investigating the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Antitumor Activity of the CDK4 Inhibitor BGB-43395, Alone or as Part of Combination Therapies in Patients With Metastatic HR+/HER2- Breast Cancer and Other Advanced Solid Tumors

Who can join

As published by the study on ClinicalTrials.gov. "Not stated" means the study hasn't said — ask the study team.

Age
18 Years and older
Sex
All sexes
Healthy volunteers
Not accepted
Compensation
Not stated

Other requirements are listed under Eligibility below. Only the study team can confirm whether you can join.

What to expect

No one can promise a trial will help you personally — that is what the research is trying to find out.

What participation involves

Not stated in the study description — ask the study team about visits and procedures.

Compensation
Not stated
  • Study-related exams and procedures are typically provided at no cost. This is how many trials work in general — confirm the details for this study with the study team.
  • Participants are monitored closely by the research team throughout the study.
  • Some participants may receive access to an investigational treatment, which is still being studied.
  • Your participation helps researchers learn whether this approach could help future patients.

About this study

In plain language

This study tests BGB-43395 alone or with fulvestrant, letrozole, or elacestrant to find recommended doses and see how well it works. It is for people with advanced breast cancer that uses hormones to grow and is HER2-negative, or certain other advanced solid tumors.

This is a dose escalation and dose expansion study to compare how well BGB-43395, a selective cyclin-dependent kinase 4 (CDK4) inhibitor, works as monotherapy or in combination with fulvestrant, letrozole, or elacestrant in participants with hormone receptor positive (HR+) and human epidermal growth factor 2 negative (HER2-) breast cancer (BC) and other advanced solid tumors. The main purpose of this study is to explore the recommended dosing for BGB-43395.

Compensation is read from the study's own description and may be missing — always confirm with the study team.

Eligibility

Who can join

  • In Phase 1a, have a solid tumor confirmed by tissue or cell tests that is advanced, has spread, or cannot be removed by surgery. It must be linked to the CDK4 protein, which helps cells grow.
  • For Phase 1a with elacestrant, have had at least 1 treatment plan for advanced cancer. Past treatment must include hormone therapy and a CDK4/6 blocker, a drug that blocks proteins that help cancer cells grow.
  • For Phase 1a safety testing with fulvestrant where approved and available, have hormone-sensitive breast cancer and at least 1 past treatment plan including hormone therapy and a CDK4/6 blocker.
  • For Phase 1b, have HR-positive/HER2-negative breast cancer: cancer that uses hormones to grow and does not have high levels of HER2 protein.
  • For Phase 1b with fulvestrant where CDK4/6 blockers are approved and available, have had 1–2 treatment plans for advanced cancer, including hormone therapy and a CDK4/6 blocker. Up to 2 past chemotherapy plans for advanced cancer are allowed.
  • For letrozole groups, have never had a CDK4/6 blocker or treatment that works throughout the body for advanced cancer.
  • Be fully active or able to do light work, with a stable activity level. Organs must work well, with no symptoms from cancer in internal organs.
  • Women with HR-positive/HER2-negative breast cancer that has spread must have gone through menopause or be receiving treatment to stop the ovaries from working.

Who can't join

  • Cancer in the tissue covering the brain and spinal cord, or cancer that has spread to the brain and is untreated or not controlled.
  • Another cancer within 3 years before the first study dose. Exceptions include the cancer being studied and certain locally recurring cancers treated with the aim of curing them.
  • Diabetes that is not controlled.
  • An infection needing medicine that works throughout the body within 28 days before the first study dose, or COVID-19 with symptoms.
  • Untreated long-term hepatitis B, or carrying hepatitis B with a virus level of at least 500 IU/mL or 2,500 copies/mL at screening.
  • Active hepatitis C, a virus that affects the liver.
  • A past stem cell transplant from a donor or an organ transplant.

Simplified for readability. The official criteria below are what the study team uses.

Official eligibility criteria

Inclusion Criteria: * Phase 1a (Dose Escalation): Participants with histologically or cytologically confirmed advanced, metastatic, or unresectable solid tumors associated with dependency on CDK4, including HR+ breast cancer, ovarian cancer, endometrial cancer, non-small cell lung cancer, and others. For combination with elacestrant, participants must have received at least 1 prior line of treatment for advanced/metastatic disease including prior endocrine therapy and CDK4/6 inhibitor in either the adjuvant or advanced/metastatic setting. * Phase 1a Safety Expansion: For combination with fulvestrant in regions where approved and available, participants with HR+ breast cancer must have received at least 1 prior line of treatment including endocrine therapy and a CDK4/6 inhibitor. For combination with letrozole, participants must be CDK4/6 inhibitor treatment naïve and have not received any previous systemic treatment for advanced disease. * Phase 1b: Participants with HR+/HER2- breast cancer. * Phase 1b: For combination with fulvestrant, participants with HR+/HER2- breast cancer enrolled in regions where CDK4/6 inhibitors are approved and available must have received 1-2 lines of therapy for advanced/metastatic disease including endocrine therapy and a CDK4/6 inhibitor. Participants can have received up to 2 lines of prior cytotoxic chemotherapy for advanced disease. For combination cohorts with letrozole, participants must be CDK4/6 inhibitor treatment naïve and have not received any previous systemic treatment for advanced disease. * Stable Eastern Cooperative Oncology Group (ECOG) Performance Status ≤ 1. * Female participants with metastatic HR+/HER2- breast cancer must be postmenopausal or receiving ovarian function suppression treatment. * Adequate organ function without symptomatic visceral disease. Exclusion Criteria: * 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, resected basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the cervix or breast). * Uncontrolled diabetes. * Infection requiring systemic antibacterial, antifungal, or antiviral therapy ≤ 28 days before the first dose of study drug(s), or symptomatic COVID-19 infection. * Participants with untreated chronic hepatitis B or chronic hepatitis B virus (HBV) carriers with HBV DNA ≥ 500 IU/mL (or ≥ 2500 copies/mL) at screening. * Participants with active hepatitis C infection. * Prior allogeneic stem cell transplantation, or organ transplantation. Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Study sites (9)

CO

FL

MI

NC

OH

TN

TX