Roche Unveils Promising Data for Giredestrant in Early Breast Cancer

Roche has announced exciting findings regarding its oral selective estrogen receptor degrader (SERD) giredestrant, which may expand treatment options for early-stage breast cancer patients. The results from the lidERA trial, focusing on patients with HR-positive, HER2-negative early breast cancer, were fully disclosed at the San Antonio Breast Cancer Symposium (SABCS) after being previewed last month. The data indicate that giredestrant resulted in a 30% reduction in invasive disease-free survival (iDFS) compared to standard endocrine therapy.

This achievement positions giredestrant as the only oral SERD to demonstrate such efficacy in a phase 3 trial focused on adjuvant settings. Roche emphasized that this marks “the first significant endocrine therapy advance in over 20 years” for patients with this subtype of breast cancer. Furthermore, there was an observed trend towards improved overall survival (OS), with 92.4% of patients receiving giredestrant still alive at three years, compared to 89.6% in the endocrine therapy group. However, this OS data is still classified as immature and has not yet reached statistical significance.

Approximately 70% of breast cancer cases are HR-positive, according to Roche. This statistic underscores the importance of addressing recurrence rates, as up to a third of patients experience a relapse during or after adjuvant endocrine therapy. The promising results from the lidERA trial may allow Roche to position giredestrant earlier in the treatment landscape than its competitors.

At present, two oral SERDs are available: Menarini/Stemline’s Orserdu (elacestrant) and Eli Lilly’s Inluriyo (imlunestrant). Both are currently approved as second-line treatments for advanced HR-positive/HER2-negative breast cancer with ESR1 mutations and are undergoing late-stage testing for adjuvant use. It is noteworthy that the lidERA trial commenced before the approvals of two CDK4/6 inhibitors—Eli Lilly’s Verzenio (abemaciclib) and Novartis’ Kisqali (ribociclib)—which have demonstrated superiority over traditional endocrine therapy in their respective phase 3 trials.

Verzenio, a blockbuster with annual sales projected to reach $5 billion, has shown a statistically significant 15.8% improvement in OS when combined with endocrine therapy in the monarchE trial. Although Kisqali did not achieve significant OS improvement in the NATALEE trial, its sales surged to $3 billion last year, benefiting from approvals for both node-positive and node-negative patients.

If giredestrant receives regulatory approval, its role in adjuvant treatment will hinge on various factors, including side effects and the risk of recurrence among patients. All three drugs in this category possess distinct safety profiles which will play a crucial role in guiding treatment decisions. Discussions at the SABCS highlighted the importance of considering whether patients fall into high, intermediate, or low-risk categories for recurrence when evaluating giredestrant’s potential in clinical practice.

As Roche advances its research, the lidERA trial’s results offer a glimpse into a new horizon for adjuvant therapy in early-stage breast cancer, potentially changing the landscape of treatment for many patients.