AstraZeneca's camizestrant shows promise in breast cancer trial

(Sharecast News) - AstraZeneca announced on Wednesday that its drug candidate camizestrant demonstrated a statistically significant and clinically meaningful improvement in progression-free survival in the first-line treatment of hormone receptor-positive, HER2-negative advanced breast cancer with an emergent ESR1 mutation. The FTSE 100 pharmaceutical giant said interim results from the phase three SERENA-6 trial showed that switching to camizestrant in combination with a CDK4/6 inhibitor improved progression-free survival compared to continuing with standard-of-care aromatase inhibitor therapy alongside a CDK4/6 inhibitor.

It said SERENA-6 was the first global phase three trial to use a circulating tumour DNA-guided approach to detect endocrine resistance and prompt a switch in therapy before disease progression.

The study monitored patients for ESR1 mutations at routine tumour scan visits, allowing treatment adjustments before disease advancement.

It said the camizestrant combination showed a trend toward improving the secondary endpoint of time to second disease progression, although data on overall survival remained immature.

The trial would continue as planned to assess the outcomes further.

AstraZeneca said the safety profile of camizestrant in combination with palbociclib, ribociclib, or abemaciclib was consistent with known safety data for the therapies, with no new concerns identified and a low rate of treatment discontinuation.

It said it would present the full data at an upcoming medical meeting and engage with global regulatory authorities.

Endocrine resistance remained a significant challenge in the treatment of HR-positive breast cancer, with ESR1 mutations emerging in approximately 30% of patients receiving first-line endocrine therapy without disease progression.

The findings from SERENA-6 supported camizestrant as a potential new treatment option for patients with emerging resistance, marking it as the first next-generation oral SERD and complete estrogen receptor antagonist to demonstrate a first-line benefit in this setting.

"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," said Susan Galbraith, AstraZeneca's executive vice-president of oncology haematology research and development.

"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."

At 0829 GMT, shares in AstraZeneca were up 0.25% at 11,962p.

Reporting by Josh White for Sharecast.com.