Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of BTX-9341 in Advanced and/or Metastatic Breast Cancer
A First-in-Human, Open-Label, Dose Escalation and Expansion Trial of BTX-9341 in Participants With Advanced and/or Metastatic Breast Cancer
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 BTX-9341 alone or with fulvestrant, an approved breast cancer drug. It checks safety, how the body handles the drug, and early signs that it works. It is for people with advanced breast cancer or breast cancer that has spread, is hormone receptor positive (HR+), and is HER2 negative (HER2-).
The purpose of this study is to test BTX-9341 alone or in combination with fulvestrant (a currently marketed medication for breast cancer) in participants with advanced and/or metastatic hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer. The study includes a dose escalation part (Part A) where small groups of participants will receive increasing doses of BTX-9341 or BTX-9341 + fulvestrant followed by a dose expansion part (Part B) where participants will receive the dose of BTX-9341 selected in Part A + fulvestrant.
Compensation is read from the study's own description and may be missing — always confirm with the study team.
Eligibility
Who can join
- Have HR+/HER2- breast cancer that has grown nearby or spread. HR+ means hormones help the cancer grow; HER2- means it does not have high levels of the HER2 protein.
- In Part A, which tests increasing doses, cancer may be measurable or not measurable, including cancer in bones. In Part B, which tests the chosen dose, cancer must be measurable.
- Have had no more than 1 chemotherapy treatment course for advanced or spreading cancer.
- For Part A: have received a CDK4/6 inhibitor, a drug that blocks proteins that help cancer cells grow. There is no limit on past hormone therapy courses for cancer that has spread.
- For Part B: have had no more than 2 hormone therapy courses, with at least 6 months on prior hormone therapy before the cancer worsened. Have had prior CDK4/6 inhibitor therapy for at least 6 months, with at most 2 courses: 1 after initial treatment and 1 for cancer that has spread.
- Meet blood count requirements. Growth-factor drugs cannot be used to meet the white blood cell requirement. Transfusions or drugs that raise platelets cannot be used to meet the platelet requirement.
- Meet the study's liver blood test requirements.
- Be able and willing to sign a form agreeing to join, and meet all study requirements in the study doctor's opinion.
Who can't join
- Have a change, called a mutation, in the RB1 gene.
- Have cancer in internal organs that causes symptoms.
- Have signs or a history of cancer spreading to the brain or spinal cord.
- Have blood-clotting problems or take blood thinners that prevent receiving fulvestrant injections or LHRH agonist injections, which lower hormone levels.
Simplified for readability. The official criteria below are what the study team uses.
Official eligibility criteria
Inclusion Criteria: * Metastatic and/or locally advanced HR+/HER2- breast cancer (dose escalation: measurable disease and/or at least 1 lytic or mixed \[lytic + sclerotic\] bone lesion that can be assessed by CT or MRI or non-measurable disease \[including bone lesions\]; dose expansion: measurable disease) * Dose escalation: (a) received not more than 1 chemotherapy in the metastatic/advanced setting; (b) no limit to the lines of endocrine therapy (monotherapy or combination therapy) in the metastatic setting; (c) received CDK4/6 inhibitor therapy * Dose expansion: (a) received not more than 1 chemotherapy in metastatic/advanced setting; (b) received not more than 2 lines of endocrine therapy (monotherapy or combination therapy) and must have been on prior endocrine therapy for at least 6 months before progression; (c) received at most 2 lines of CDK4/6 inhibitor therapy (1 in the adjuvant setting and 1 in the metastatic setting) and must have been on prior CDK4/6 inhibitor therapy for at least 6 months * Acceptable hematologic function 1. ANC ≥ 1500 per mL. Note: Use of growth-factors to maintain the ANC criterion is prohibited. 2. Platelet count ≥ 100,000 per mL. Note: Use of transfusions or thrombopoietic agents to achieve the baseline platelet count criterion is prohibited. 3. Hemoglobin ≥ 9.0 g/dL. Note: Packed red blood cell transfusion is allowed up to 14 days prior to trial entry. * Acceptable liver function 1. Bilirubin ≤ 2.0 × institutional upper limit of normal (ULN) (or \< 3.0 × institutional ULN if Gilbert's disease is present) 2. Alanine transaminase (ALT)/aspartate aminotransferase (AST) ≤ 3.0 × institutional ULN (≤ 5.0 × institutional ULN if liver metastases present) 3. Alkaline phosphatase ≤ 2.5 × institutional ULN (≤ 5.0 × institutional ULN if bone or liver metastases present) * Able and willing to sign informed consent * Meets all study requirements in the opinion of the Investigator Exclusion Criteria: * RB1 (retinoblastoma) gene mutation * Symptomatic visceral disease * Clinical evidence or history of central nervous system metastasis * Abnormalities in coagulation, such as bleeding diathesis, or treatment with anticoagulants precluding injections of fulvestrant or luteinizing hormone-releasing hormone (LHRH) agonist
Study sites (6)
MN
- Biotheryx Investigative Site · Rochester, MN 55905Biotheryx Investigative Site · Study contactMore trials in Rochester
NE
- Biotheryx Investigative Site · Omaha, NE 68130Biotheryx Investigative Site · Study contactMore trials in Omaha
TX
- Biotheryx Investigative Site · Houston, TX 77030Biotheryx Investigative Site · Study contactMore trials in Houston
- Biotheryx Investigative Site · San Antonio, TX 78229Biotheryx Investigative Site · Study contactMore trials in San Antonio
UT
- Biotheryx Investigative Site · West Valley City, UT 84119Biotheryx Investigative Site · Study contactMore trials in West Valley City
VA
- Biotheryx Investigative Site · Fairfax, VA 22031Biotheryx Investigative Site · Study contactMore trials in Fairfax