Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of BTX-9341 in Advanced And/or Metastatic Breast Cancer

Phase 1

Recruiting

• Conditions: Breast Cancer
• Interventions: Drug: BTX-9341; Drug: Fulvestrant

• Registration Number: NCT06515470
• Lead Sponsor: Biotheryx, Inc.

Brief Summary

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 group...

Detailed Description

This first-in-human (FIH), Phase 1 study of BTX-9341 is multicenter, nonrandomized, and open-label to evaluate the safety, tolerability, pharmacokinetics (PK), and preliminary efficacy of BTX-9341 in participants with advanced and/or metastatic HR+/HER2 breast cancer. The study will include a dose escalation part (Part A) followed by a dose expansion part (P...

Basic Information
|
Recruitment & Eligibility
|
Study & Design
|
Trial Locations

Study Timeline

• Study Start: 2024-07-03
• Study First Submitted: 2024-07-17
• Study First Submitted QC: 2024-07-17
• Study First Posted: 2024-07-23
• Status Verified: 2024-10
• Last Update Submitted: 2024-10-26
• Last Update Posted: 2024-10-29
• Primary Completion: 2027-09-30
• Study Completion: 2027-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 82

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

Read More

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

Read More

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
BTX-9341 (Part A)	BTX-9341	BTX-9341 capsule(s) administered orally once daily (QD) in 28-day cycles
BTX-9341 + fulvestrant (Part A)	BTX-9341	BTX-9341 capsule(s) administered orally QD in 28-day cycles and fulvestrant intermuscular injections on Day 15 and then once every 28 days
BTX-9341 + fulvestrant (Part A)	Fulvestrant	BTX-9341 capsule(s) administered orally QD in 28-day cycles and fulvestrant intermuscular injections on Day 15 and then once every 28 days
BTX-9341 + fulvestrant (Part B)	Fulvestrant	BTX-9341 capsule(s) administered orally QD in 28-day cycles and fulvestrant intermuscular injections on Day 15 and then once every 28 days
BTX-9341 + fulvestrant (Part B)	BTX-9341	BTX-9341 capsule(s) administered orally QD in 28-day cycles and fulvestrant intermuscular injections on Day 15 and then once every 28 days

Primary Outcome Measures

Name	Time	Method
Safety and Tolerability of BTX-9341	Up to 28 days after last dose of BTX-9341	Frequency and severity, incidence of treatment-emergent and treatment-related adverse events using NCI-CTCAE v5.0
Part A: Number of Participants With Dose Limiting Toxicities (DLTs)	28 days	DLT rate in Cycle 1
Part A: Determine MTD/MED of BTX-9341 in monotherapy	Approximately 1 year from study start	Based on CTCAE v5.0 assessment of adverse events
Part A: Determine MTD/MED of BTX-9341 in combination therapy	Approximately 18 months from study start	Based on CTCAE v5.0 assessment of adverse events
Part B Combination Therapy: Objective Response (OR) rate	Approximately 18 months from start of Part B	OR is the confirmed complete response (CR) or partial response (PR) according to Response Evaluation Criteria in Solid Tumor (RECIST) version 1.1 as determined by Investigator assessment

Trial Locations

Locations (1)

Biotheryx Investigative Site; 🇺🇸 San Antonio, Texas, United States