FDA extends review of AstraZeneca’s breast cancer drug following advisory panel setback
The U.S. Food and Drug Administration has extended its review period for AstraZeneca's (NASDAQ:AZN) New Drug Application for camizestrant, delaying a final decision on the advanced breast cancer treatment.
The regulator extended the Prescription Drug User Fee Act action date to allow for the evaluation of additional data requested from the drugmaker to support the regulatory submission.
The proposed therapy combines camizestrant with a cyclin-dependent kinase (CDK) 4/6 inhibitor for the first-line treatment of hormone receptor-positive, HER2-negative advanced breast cancer in patients whose tumors display an emergent ESR1 mutation.
The application is built on data from the pivotal SERENA-6 Phase III trial, which showed positive outcomes when patients switched to the camizestrant combination after an ESR1 mutation was detected in circulating tumor DNA (ctDNA).
However, the regulatory path in the U.S. hit a snag in April 2026 when the FDA’s Oncologic Drugs Advisory Committee did not reach a majority vote in favor of the treatment strategy.
The panel raised questions regarding the clinical benefit of changing therapies prior to visible radiographic progression of the disease.
In response to the committee's stance, AstraZeneca provided supplementary analyses to the FDA, including ctDNA clearance data linked to longer-term efficacy outcomes, which are scheduled to be presented publicly at the American Society of Clinical Oncology meeting on June 2, 2026.
Despite the regulatory slowdown in the U.S., AstraZeneca’s clinical strategy is gaining validation in other international jurisdictions.
On May 22, 2026, the European Medicines Agency's Committee for Medicinal Products for Human Use adopted a positive opinion recommending the approval of the camizestrant combination for this patient population.
The treatment has already secured regulatory clearances in the United Arab Emirates and Saudi Arabia, while parallel marketing applications remain under active review by regulators in Japan and several other nations.