Actively Recruiting
A Study to Evaluate the Safety and Tolerability of TOS-358 in Women With HR+ HER2- Breast Cancer
Led by Totus Medicines · Updated on 2026-04-22
241
Participants Needed
18
Research Sites
250 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
The goal of this clinical trial is to evaluate the safety and efficacy of TOS-358 in women with HR+ HER2- metastatic breast cancer whose tumors have a mutation in PIK3CA and who meet all other study enrollment criteria. The main questions it aims to answer are: 1. Phase 1a: what is the maximum tolerated dose and recommended dose for phase 2? 2. Phase 1a: how safe and tolerable is TOS-358 at different dose levels when taken orally once or twice per day? 3. Phase 1b: how safe and effective is TOS-358 when given with standard of care medicines for HR+HER2- metastatic breast cancer (fulvestrant and CDK4/6i)
CONDITIONS
Official Title
A Study to Evaluate the Safety and Tolerability of TOS-358 in Women With HR+ HER2- Breast Cancer
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Adult women aged 18 years or older
- Histologically confirmed locally advanced, recurrent, or metastatic HR+/HER2- breast cancer
- Up to 3 prior lines of therapy for metastatic disease
- Willing and able to provide written informed consent
- Known PIK3CA mutations or amplifications confirmed by a CAP/CLIA-certified or equivalent lab using a validated test
- Measurable or evaluable disease by RECIST 1.1 criteria
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Life expectancy of at least 6 months as determined by the investigator
- Adequate bone marrow, liver, and kidney function within 14 days prior to first dose
- Fasting plasma glucose less than or equal to 140 mg/dL and hemoglobin A1c (HbA1c) less than or equal to 7.0%
- Available archived or fresh tumor tissue sample for central laboratory detection of PIK3CA mutation
You will not qualify if you...
- Established diagnosis of diabetes mellitus type 1 or uncontrolled diabetes mellitus type 2
- Known active central nervous system (CNS) metastases
- Presence of PTEN mutations
AI-Screening
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Trial Site Locations
Total: 18 locations
1
Northwestern Memorial Hospital
Chicago, Illinois, United States, 60611
Actively Recruiting
2
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States, 02215
Actively Recruiting
3
Dana-Farber Cancer Institute
Boston, Massachusetts, United States, 02215
Actively Recruiting
4
Comprehensive Cancer Centers of Nevada
Las Vegas, Nevada, United States, 89169
Actively Recruiting
5
University of Pennsylvania
Philadelphia, Pennsylvania, United States, 19106
Actively Recruiting
6
Sarah Cannon Cancer Center
Nashville, Tennessee, United States, 37203
Actively Recruiting
7
Vanderbilt-Ingram Cancer Center
Nashville, Tennessee, United States, 37232
Actively Recruiting
8
Texas Oncology - Flower Mound
Flower Mound, Texas, United States, 75028
Actively Recruiting
9
Virginia Cancer Specialists
Fairfax, Virginia, United States, 22031
Actively Recruiting
10
NEXT Oncology - Hospital Quironsalud Barcelona - PPDS
Barcelona, Spain, 08023
Actively Recruiting
11
START Barcelona HM Nou Delfos
Barcelona, Spain, 08023
Actively Recruiting
12
Instituto de Investigacion Oncologica Vall dHebron (VHIO) - EPON
Barcelona, Spain, 08035
Actively Recruiting
13
Hospital Clinico San Carlos
Madrid, Spain, 28040
Actively Recruiting
14
START MADRID Hospital Universitario Fundacion Jimenez Diaz - EDOS
Madrid, Spain, 28050
Actively Recruiting
15
START MADRID Hospital Universitario HM Sanchinarro - CIOCC
Madrid, Spain, 28050
Actively Recruiting
16
Clinica Universidad de Navarra
Pamplona, Spain, 31008
Actively Recruiting
17
NEXT Oncology - Hospital Quironsalud Madrid - PPDS
Pozuelo de Alarcón, Spain, 28223
Actively Recruiting
18
Hospital Clinico Universitario de Valencia
Valencia, Spain, 46010
Actively Recruiting
Research Team
C
Clinical Trials
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
3
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