A Study to Evaluate the Safety and Tolerability of TOS-358 in Women With HR+ HER2- Breast Cancer
Public ClinicalTrials.gov record NCT05683418. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
A Study to Evaluate the Safety and Tolerability of the Covalent Phosphoinositide-3-Kinase (PI3K)-Alpha Inhibitor, TOS-358, in Adult Subjects With Select Solid Tumors
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
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)
Study identification
- NCT ID
- NCT05683418
- Recruitment status
- Recruiting
- Study type
- Interventional
- Phase
- Phase 1
- Enrollment
- 241 participants
Conditions and interventions
Conditions
Eligibility (public fields only)
- Age range
- 18 Years and older
- Sex
- Female
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Feb 14, 2023
- Primary completion
- Nov 30, 2027
- Completion
- Nov 30, 2027
- Last update posted
- Apr 21, 2026
2023 – 2027
United States locations
- U.S. sites
- 9
- U.S. states
- 7
- U.S. cities
- 7
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Northwestern Memorial Hospital | Chicago | Illinois | 60611 | Recruiting |
| Beth Israel Deaconess Medical Center | Boston | Massachusetts | 02215 | Recruiting |
| Dana-Farber Cancer Institute | Boston | Massachusetts | 02215 | Recruiting |
| Comprehensive Cancer Centers of Nevada | Las Vegas | Nevada | 89169 | Recruiting |
| University of Pennsylvania | Philadelphia | Pennsylvania | 19106 | Recruiting |
| Sarah Cannon Cancer Center | Nashville | Tennessee | 37203 | Recruiting |
| Vanderbilt-Ingram Cancer Center | Nashville | Tennessee | 37232 | Recruiting |
| Texas Oncology - Flower Mound | Flower Mound | Texas | 75028 | Recruiting |
| Virginia Cancer Specialists | Fairfax | Virginia | 22031 | Recruiting |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
Non-U.S. locations
This page focuses on the U.S. directory. The official record also lists 9 non-U.S. sites.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT05683418, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Apr 21, 2026 · Synced Sep 2, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT05683418 live on ClinicalTrials.gov.