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
← catalyst calendarNCT05216432 · readout in 254 d
Sponsored by Relay Therapeutics, Inc. (industry) · RLAY — their whole pipeline →.
Phase
Phase 1
Status
Recruiting
Study type
Interventional
Design
Non randomized · None · Treatment
Enrollment
930estimated
Sites
37
Countries
Australia, France, Italy +2
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2021-12-08 | actual | When the study began enrolling |
| Primary completion | 2027-04-30 | estimated | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2027-04-30 | estimated | The whole study's end, after follow-up |
| First posted | 2022-01-31 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2025-09-22 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Conditions
- 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 — also filed as Faslodex
- Drug: Palbociclib 125mg — also filed as Ibrance
- Drug: Ribociclib 400mg — also filed as Kisqali
- Drug: Ribociclib 600mg — also filed as Kisqali
- Drug: PF-07220060 100mg
- Drug: PF-07220060 300 mg
Primary outcomes
what the primary-completion date above is the date OFDetermination of maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of RLY-2608 as a single agent
measured Cycle 1 (4-week cycle) of treatment for MTD and at the end of every cycle (4-week cycles) for RP2D until study discontinuation, approximately 24 months
Determination of maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of RLY-2608 in combination with fulvestrant
measured Cycle 1 (4-week cycle) of treatment for MTD and at the end of every cycle (4-week cycles) for RP2D until study discontinuation, approximately 24 months
Determination of maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of RLY-2608 in combination with fulvestrant and a CDK 4/6 inhibitor (palbociclib, ribociclib), and in combination with CDK4 inhibitor (PF-07220060) and fulvestrant
measured Cycle 1 (4-week cycle) of treatment for MTD and at the end of every cycle (4-week cycles) for RP2D until study discontinuation, approximately 24 months
Number of patients with adverse events and serious adverse events of RLY-2608 as a single agent
measured Every cycle (4-week cycles) until study discontinuation, approximately 24 months
Number of patients with adverse events and serious adverse events of RLY-2608 in combination with fulvestrant
measured Every cycle (4-week cycles) until study discontinuation, approximately 24 months
Number of patients with adverse events and serious adverse events of RLY-2608 in combination with fulvestrant and a CDK 4/6 inhibitor (palbociclib, ribociclib), and in combination with CDK4 inhibitor (PF-07220060) and fulvestrant
measured Every cycle (4-week cycles) until study discontinuation, approximately 24 months
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