Roche’s Giredestrant Combination Shows Promise in Breast Cancer Treatment Despite Trial Setback

Basel, Switzerland – March 9, 2026 – Roche announced today that its phase III persevERA study evaluating giredestrant in combination with palbociclib for estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer did not meet its primary objective. While the combination did not demonstrate a statistically significant improvement in progression-free survival compared to letrozole plus palbociclib, Roche remains optimistic about the potential of giredestrant as a modern standard of care in breast cancer treatment. Source

persevERA Study Results

The persevERA trial, a randomized, double-blind, placebo-controlled study, investigated giredestrant plus palbociclib against letrozole plus palbociclib as a first-line treatment for locally advanced or metastatic ER+/HER2- breast cancer. Although the study did not achieve its primary endpoint of statistically significant progression-free survival, a numerical improvement was observed. Source The combination of giredestrant and palbociclib was found to be well-tolerated, with adverse events consistent with the known safety profiles of each individual treatment.

Giredestrant’s Broader Development Program

Despite the persevERA results, Roche is continuing to advance the development of giredestrant across multiple treatment settings. The company recently received FDA acceptance for a New Drug Application (NDA) for giredestrant in combination with everolimus for ESR1-mutated, ER+/HER2- advanced breast cancer. Source The FDA is expected to make a decision on the application by December 18, 2026. This combination could potentially be the first oral selective estrogen receptor degrader (SERD) approved for use after CDK4/6 inhibitor therapy. Source

the phase III lidERA study, which evaluated giredestrant as an adjuvant endocrine treatment for early-stage ER+/HER2- breast cancer, demonstrated a 30% reduction in the risk of invasive disease recurrence or death. Source These results, presented at the 2025 San Antonio Breast Cancer Symposium, position giredestrant as a potential new standard of care for early-stage disease. Source

Another ongoing phase III study, pionERA, is evaluating giredestrant in combination with a physician’s choice of CDK4/6 inhibitor for endocrine-resistant ER+/HER2- breast cancer, with results expected in 2027. Source

Expert Perspective

“While persevERA didn’t meet its primary objective, we are confident in the potential of giredestrant to grow a new standard-of-care endocrine therapy in early and advanced ER-positive breast cancer,” said Levi Garraway, MD, PhD, Roche’s Chief Medical Officer and Head of Global Product Development. Source

Looking Ahead

Roche remains committed to transforming ER-positive breast cancer care, building on the success of lidERA in early-stage disease and evERA in the advanced setting. Source The upcoming FDA decision on the giredestrant/everolimus combination and the anticipated results from the pionERA study will provide further insights into the role of giredestrant in the treatment of this prevalent cancer.