# A Study to Evaluate the Safety and Tolerability of TOS-358 in Women With HR+ HER2- Breast Cancer

> **NCT05683418** · PHASE1 · RECRUITING · sponsor: **Totus Medicines** · enrollment: 241 (estimated)

## Conditions studied

- HR+/HER2-negative Breast Cancer

## Interventions

- **DRUG:** TOS-358
- **DRUG:** Fulvestrant
- **DRUG:** Palbociclib
- **DRUG:** Ribociclib

## Key facts

- **NCT ID:** NCT05683418
- **Lead sponsor:** Totus Medicines
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE1
- **Study type:** INTERVENTIONAL
- **Status:** RECRUITING
- **Start date:** 2023-02-15
- **Primary completion:** 2027-12
- **Final completion:** 2027-12
- **Target enrollment:** 241 (ESTIMATED)
- **Last updated:** 2026-04-22


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05683418

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05683418, "A Study to Evaluate the Safety and Tolerability of TOS-358 in Women With HR+ HER2- Breast Cancer". Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/clinical/NCT05683418. Licensed CC0.

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