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A Study to Evaluate the Safety and Tolerability of TOS-358 in Adults With HR+ Breast Cancer and Other Select Solid Tumors
Trial Status: active
The goal of this clinical trial is to evaluate the safety of TOS-358 in adults with
select solid tumors who meet study enrollment criteria. The main questions it aims to
answer are:
1. what is the maximum tolerated dose and recommended dose for phase 2?
2. how safe and tolerable is TOS-358 at different dose levels when taken orally once or
twice per day?
Inclusion Criteria
Locally advanced, recurrent, or metastatic, incurable (any number of previous lines of therapy is allowed), histologically or cytologically confirmed; HR +/HER2- breast cancer; squamous cell carcinoma of the head and neck; urothelial cancer; or endometrial cancer with no more than 3 prior lines of therapy for metastatic disease
Willing and able to provide written informed consent for this study
Adults ≥ 18 years old at time of consent
Known PIK3CA mutations or amplifications as determined at a CAP/CLIA-certified or equivalently accredited diagnostic laboratory using a validated test
Measurable disease by RECIST 1.1
Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
Life expectancy ≥ 6 months, as determined by the investigator
Adequate bone marrow, liver, and kidney function within 14 days prior to first dose of investigational product
Available archived or fresh tumor tissue sample for detection of PIK3CA mutation by central laboratory test Key
Exclusion Criteria
Recent systemic anticancer treatment prior to start of treatment (EXCEPTION: Patients with breast cancer who were receiving a fulvestrant-containing regimen at the time of informed consent may remain on fulvestrant while receiving study treatment)
For non-breast cancer: prior treatment with any PI3K, AKT, or mTOR inhibitor, or any agent whose mechanism of action is to inhibit the PI3K-AKT-mTOR pathway,
Has an established diagnosis of diabetes mellitus type 1 or has uncontrolled diabetes mellitus type 2 requiring antihyperglycemic medication
Known active central nervous system (CNS) metastases.
Additional locations may be listed on ClinicalTrials.gov for NCT05683418.
