The European Union has approved the combination therapy of AstraZeneca's drug Etcamah (camizestrant) with a CDK4/6 inhibitor (palbociclib, ribociclib, or abemaciclib).

This approval is for treating adult patients with locally advanced or metastatic estrogen receptor-positive, HER2-negative breast cancer who have a detected ESR1 mutation and did not experience disease progression during prior first-line endocrine therapy combined with a CDK4/6 inhibitor.

AstraZeneca PLC (AZN.US) highlighted that Etcamah is currently the only new-generation oral selective estrogen receptor degrader (SERD) approved for first-line treatment of breast cancer.

Prior to this EU authorization, the product had already received approvals in Japan, the United Arab Emirates, and Saudi Arabia, with marketing applications also submitted in regions including the United States.

The approval is based on positive outcomes from the pivotal Phase III SERENA-6 study, a randomized, double-blind, global, multicenter trial.

This trial evaluated the efficacy and safety of Etcamah combined with a CDK4/6 inhibitor in patients with HR-positive, HER2-negative advanced breast cancer.

In a prespecified interim analysis, the Etcamah combination therapy reduced the risk of disease progression or death by 56% compared to the standard treatment of an aromatase inhibitor (AI) combined with a CDK4/6 inhibitor.

The hazard ratio (HR) was 0.44, with a 95% confidence interval of 0.31 to 0.60, and the result was statistically significant.

The median progression-free survival (PFS) was 16 months for the Etcamah group versus 9.2 months for the control group.

Data updated at the 2026 ASCO meeting showed that switching to Camizestrant led to a median 99% decrease in total circulating tumor DNA (ctDNA) at week 8.

In contrast, the control group continuing on AI plus a CDK4/6 inhibitor showed a 64% increase.

Regarding safety, the combined regimen's profile was consistent with the known safety characteristics of each individual drug.

No new safety concerns were identified, and discontinuation rates were very low and similar between the two treatment groups.

It is noteworthy that in April 2026, the U.S. FDA's Oncologic Drugs Advisory Committee (ODAC) voted 3-6 against recommending approval for Etcamah.

The committee expressed that the existing clinical data did not sufficiently demonstrate that switching therapy prior to radiological progression provides patients with a substantial, clinically meaningful long-term benefit.

Following this, the FDA extended the Prescription Drug User Fee Act (PDUFA) action date to allow for the review of additional supplementary data.