AstraZeneca (AZ) has announced positive results from a late-stage trial of camizestrant in a subset of advanced breast cancer patients.
The phase 3 SERENA-6 study randomised patients with HR-positive, HER2-negative advanced breast cancer whose tumours had an emergent ESR1 mutation to receive either AZ’s candidate or an aromatase inhibitor (anastrozole or letrozole), both taken alongside a CDK4/6 inhibitor (palbociclib, ribociclib or abemaciclib).
The camizestrant combination demonstrated a highly statistically significant and clinically meaningful improvement in the primary endpoint of progression-free survival compared to standard-of-care treatment with an aromatase inhibitor and CDK4/6 inhibitor, AZ said.
The key secondary endpoints of time to second disease progression (PFS2) and overall survival were immature at the time of the interim analysis, but the company noted that its camizestrant combination demonstrated a trend toward improvement in PFS2.
The safety profile of the camizestrant combination was also shown to be consistent with the known safety profile of each medicine.
Breast cancer is the second most common cancer worldwide, with more than two million cases diagnosed in 2022.
Patients with HR-positive breast cancer, the most common subtype of the disease, are frequently treated with endocrine therapies that target oestrogen receptor (ER)-driven disease in combination with CDK4/6 inhibitors.
However, many patients with advanced disease develop resistance to these medicines, and mutations in the ESR1 gene, which develop during treatment, are a key driver of this.
AZ’s camizestrant, an investigational next-generation oral selective ER degrader and complete ER antagonist, is currently being evaluated in three additional trials when used as a monotherapy or in combination with other agents in this specific type of breast cancer.
Susan Galbraith, executive vice president, oncology haematology research and development, AZ, said the results from SERENA-6 “demonstrate the versatility of camizestrant in combination with all the widely approved CDK4/6 inhibitors to provide a well-tolerated new potential treatment option in the first-line setting” for this patient population.
“This critical read-out moves us one step closer to realising the potential of camizestrant to become a new standard-of-care as we look to shift the treatment paradigm and establish this new endocrine therapy backbone in HR-positive breast cancer,” she added.