Biotechnology company Genentech, a member of the Roche Group (SIX: RO, ROG) (OTCQX: RHHBY), on Monday announced positive Phase III results from its evERA study evaluating investigational giredestrant in combination with everolimus for estrogen receptor (ER)-positive, HER2-negative advanced breast cancer.

The trial met both co-primary endpoints, showing significant improvement in progression-free survival in the intention-to-treat and ESR1-mutated populations compared with standard-of-care therapy plus everolimus.

Findings also indicated a positive trend in overall survival, though data remain immature and follow-up is ongoing. The all-oral regimen was well tolerated, with adverse events consistent with known safety profiles and no new signals observed.

This marks the first positive head-to-head Phase III trial testing an oral selective estrogen receptor degrader-containing combination against standard care. The results suggest potential to improve outcomes in patients who have progressed after CDK4/6 inhibitors and endocrine therapy, a population with limited treatment options.

ER-positive breast cancer represents around 70% of all breast cancer cases, but resistance to endocrine therapy often leads to poor outcomes. The giredestrant plus everolimus combination targets two signaling pathways, aiming to delay progression while minimizing treatment burden by avoiding injections.

Genentech plans to present the data at an upcoming medical meeting and submit results to health authorities for regulatory review.