AstraZeneca has reported positive outcomes from a planned interim analysis of the double-blind Phase III SERENA-6 trial of camizestrant plus a cyclin-dependent kinase (CDK) 4/6 inhibitor as first-line treatment of individuals with hormone receptor (HR)-positive, HER2-negative advanced breast cancer.
It is intended for those whose tumours have an emergent oestrogen receptor 1 mutation.
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CDK4/6 inhibitors include palbociclib, ribociclib or abemaciclib.
In the trial, the combo showed a significant improvement in progression-free survival (PFS), the primary endpoint.
This trial used a circulating tumour DNA (ctDNA)-guided method for identifying endocrine resistance emergence for these particular patients and determining the therapy switches before the progression of the disease.
It compared the effects of switching to the camizestrant combo against continuing with a standard aromatase inhibitor treatment combo with a CDK4/6 inhibitor.
While the key secondary endpoints of overall survival and time-to-second disease progression (PFS2) are still maturing, the combo showed trends suggesting potential improvement in PFS2. These endpoints will continue to be assessed as planned during the trial.
In the trial, the combination has maintained a safety profile consistent with the known safety profile.
Importantly, there were no safety concerns observed, and patient discontinuation rates were low and comparable across both treatment groups.
AstraZeneca oncology haematology R&D executive vice-president Susan Galbraith said: “These impressive results 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 the one in three patients with HR-positive, HER2-negative advanced breast cancer whose tumours develop ESR1 mutations during treatment with an aromatase inhibitor in combination with a CDK4/6 inhibitor.”
A selective oestrogen receptor degrader, camizestrant is presently under evaluation in Phase III trials targeting HR-positive breast cancer.
This development follows AstraZeneca’s recent announcement of positive outcomes from the NIAGARA trial of Imfinzi in combination with neoadjuvant chemotherapy.
