GDC-4198 alone or with giredestrant versus abemaciclib + giredestrant in ER-positive, HER2-negative advanced breast cancer after CDK4/6 inhibitor progression

Phase 2, randomised, open-label trial in breast cancer comparing GDC-4198 monotherapy, GDC-4198 + giredestrant and Abemaciclib + giredestrant (3 arms). Primary endpoints: Incidence and severity of adverse events, Change from baseline in selected vital signs and 3 more. Planned start Dec 2025; status: authorised.