On April 30, 2026 Totus Medicines, a clinical stage, precision medicines company leveraging AI-powered small molecule drug discovery to advance a differentiated pipeline of therapeutics against high-value, historically difficult to drug targets in multiple therapeutic areas, reported that interim Phase 1b clinical data from its ongoing study of TOS-358, a next-generation pan-mutant, covalent, alpha-specific PI3K inhibitor, in combination with Fulvestrant, in heavily pre-treated metastatic HR+/HER- breast cancer patients, will be presented at the European Society for Medical Oncology (ESMO) (Free ESMO Whitepaper) Breast Cancer Annual Congress, taking place in Berlin, Germany, May 5-8, 2026.
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Presentation Details:
Conference: ESMO (Free ESMO Whitepaper) Breast Cancer 2026
Session: Poster Presentation
Date / Time: 13:15, Thursday, May 7, 2026
TOS-358 is an oral, highly selective, pan-mutant, covalent PI3Ka inhibitor that achieves >95% continuous target engagement at clinically relevant doses for deep and durable inhibition of PI3K-AKT signaling. PI3Ka driver mutations are present in approximately 40% of ER-positive/HER2-negative breast cancer, 50% of endometrial adenocarcinoma, and a meaningful subset of head and neck squamous cell carcinoma (HNSCC) patients. Totus Medicines is advancing TOS-358 as a potential best-in-class PI3Ka inhibitor into Ph1b clinical development across selected solid tumor indications.
(Press release, Totus Medicines, APR 30, 2026, View Source [SID1234664992])