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Drug intelligence / Profile preview
TOS-358 + fulvestrant
- Development stage
- Phase 1
- Lead developer
- Totus Medicines
- Modality
- Small Molecules
- Administration
- Intramuscular, Oral
01
Overview
TOS-358 + fulvestrant is a combination therapy consisting of TOS-358, an oral, covalent, pan-mutant, alpha-selective phosphoinositide 3-kinase alpha (PI3Kα) inhibitor, and fulvestrant, a selective estrogen receptor degrader (SERD). Developed by Totus Medicines, this combination is being evaluated for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2−) metastatic breast cancer harboring PIK3CA mutations. TOS-358 achieves deep and durable inhibition of PI3K-AKT signaling by covalently binding to a cysteine residue in PI3Kα, while fulvestrant binds to and degrades the estrogen receptor, blocking estrogen-mediated signaling. Together, the doublet therapy aims to overcome resistance mechanisms and provide enhanced antitumor efficacy with a favorable safety profile.
- Other names
- fulvestrant + TOS-358fulvestrant and TOS-358TOS-358 + fulvestrantTOS-358 + fulvestrant doublet therapyTOS-358 and fulvestrantTOS358 and fulvestrantTOS 358 and fulvestrant
02
Targets
AKT (RAC-alpha serine/threonine-protein kinase)ESR1 (ERα)PIK3CA (Phosphoinositide 3-kinase alpha)mTOR (Mammalian target of rapamycin kinase)
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