Clinical Trial

A Study to Evaluate the Effect of GDC-4198 Alone and in Combination With Giredestrant Versus Abemaciclib and Giredestrant in Participants With Locally Advanced or Metastatic Estrogen Receptor-Positive (ER+), Human Epidermal Growth Factor Receptor-Negative (HER2-) Breast Cancer

Study acronym: MoonROSE
Recruiting Phase 1/2
View on ClinicalTrials.gov →
Summary
The purpose of this study is to assess the safety of GDC-4198 alone and in combination with giredestrant and also the efficacy of GDC-4198 + giredestrant versus abemaciclib + giredestrant in participants with locally advanced or metastatic ER+, HER2- breast cancer. The study consists of 2 phases: Phase Ib and Phase II. Phase Ib will evaluate the safety and pharmacokinetics (PK) of GDC-4198 alone and in combination with giredestrant. Phase II stage will compare the activity and safety of GDC-4198 and giredestrant with abemaciclib and giredestrant.
Protocol Amendment History 4 changes
notable Trial sites expanded: 45 -> 52 locations 2026-07-14
notable Trial sites expanded: 39 -> 45 locations 2026-06-17
notable Trial sites expanded: 35 -> 39 locations 2026-05-19
notable Trial sites expanded: 21 -> 35 locations 2026-04-22
Trial Details
NCT Number NCT07100106
Lead Sponsor Genentech, Inc.
Collaborators: Roche (China) Holding Ltd.
Conditions Breast Cancer
Enrollment 285 participants
Start Date 2025-10-07
Primary Completion 2028-08-31 (estimated)
Study Completion 2028-08-31 (estimated)
Updated on ClinicalTrials.gov 2026-07-13