# First-in-Human Study of Mutant-selective PI3Kα Inhibitor, RLY-2608, as a Single Agent in Patients With Advanced Solid Tumors and in Combination With Endocrine Therapy +/- a CDK4/6 or CDK4 Inhibitor in Patients With Advanced Solid Tumors or Advanced Breast Cancer

> **NCT05216432** · PHASE1 · RECRUITING · sponsor: **Relay Therapeutics, Inc.** · enrollment: 930 (estimated)

## Conditions studied

- PIK3CA Mutation
- Solid Tumor, Adult
- HER2-negative Breast Cancer
- Breast Cancer
- Metastatic Breast Cancer
- Advanced Breast Cancer
- Unresectable Solid Tumor

## Interventions

- **DRUG:** RLY-2608
- **DRUG:** Fulvestrant
- **DRUG:** Palbociclib 125mg
- **DRUG:** Ribociclib 400mg
- **DRUG:** Ribociclib 600mg
- **DRUG:** PF-07220060 100mg
- **DRUG:** PF-07220060 300 mg

## Key facts

- **NCT ID:** NCT05216432
- **Lead sponsor:** Relay Therapeutics, Inc.
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE1
- **Study type:** INTERVENTIONAL
- **Status:** RECRUITING
- **Start date:** 2021-12-08
- **Primary completion:** 2027-04-30
- **Final completion:** 2027-04-30
- **Target enrollment:** 930 (ESTIMATED)
- **Last updated:** 2025-09-22


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05216432

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05216432, "First-in-Human Study of Mutant-selective PI3Kα Inhibitor, RLY-2608, as a Single Agent in Patients With Advanced Solid Tumors and in Combination With Endocrine Therapy +/- a CDK4/6 or CDK4 Inhibitor in Patients With Advanced Solid Tumors or Advanced Breast Cancer". Retrieved via AI Analytics 2026-07-19 from https://api.ai-analytics.org/clinical/NCT05216432. Licensed CC0.

---

*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*