A combination of giredestrant and everolimus outperformed standard hormone therapy in a major phase 3 trial for a common form of advanced breast cancer, according to results published in the New England Journal of Medicine.
The trial focused on oestrogen receptor-positive, HER2-negative advanced breast cancer — the most frequently diagnosed type of breast cancer in women. Patients in this category have tumours that are fuelled by oestrogen but do not overproduce a protein called HER2. The study tested giredestrant, a drug that both blocks and breaks down oestrogen receptors (known as an ER degrader and full ER antagonist), given alongside everolimus, a drug that slows cancer cell growth.
Patients who received the giredestrant-everolimus combination lived longer without their cancer getting worse — a measure doctors call progression-free survival — than those on the current standard treatment of endocrine therapy combined with everolimus. The safety profile of both treatment arms was described as similar.
The findings come from the evERA Breast Cancer trial, a full phase 3 study, meaning it is among the most rigorous types of clinical trial used to test new treatments before they can be considered for wider use.
No regulatory approval has yet been granted, though Roche announced in February 2026 that the FDA had accepted a new-drug application for giredestrant. Application acceptance does not constitute approval. Patients should not adjust their current treatment on the basis of trial results alone.
Anyone with questions about a breast cancer diagnosis or current treatment should speak to their oncology team or contact NHS 111 for general guidance.
Source: @NEJM