NCT06515470

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

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 82 (estimated)
• Sponsor: Biotheryx, Inc. · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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 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.

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 (Part B). During Part A, BTX-9341 will initially be dose escalated alone and then in combination with fulvestrant. A single combination therapy cohort of BTX-9341 + fulvestrant will be further explored in Part B. BTX-9341 will be administered orally in 28-day treatment cycles.

Conditions

• Breast Cancer

Interventions

Type	Name	Description
DRUG	BTX-9341	Daily oral dose in 28-day cycles until maximum tolerated dose (MTD) or maximum evaluable dose (MED) determined
DRUG	Fulvestrant	500 mg intramuscular injections on Day 15 and then every 28 days
DRUG	BTX-9341	Daily oral dose in 28-day cycles using dose determined in Part A

Timeline

• Start date: 2024-07-03
• Primary completion: 2027-09-30
• Completion: 2027-12-31
• First posted: 2024-07-23
• Last updated: 2025-06-06

Locations

6 sites across 1 country: United States

Regulatory

• FDA-regulated drug study