The FDA has delayed a decision on the approval of AstraZeneca’s camizestrant, deferring its ruling to review analyses filed after an advisory committee voted against the breast cancer prospect.
AstraZeneca filed for FDA approval of the oral SERD based on a phase 3 switching study. Patients in the Serena-6 trial received an aromatase inhibitor and a CDK4/6 inhibitor. After detecting an ESR1 mutation, investigators swapped the aromatase inhibitor for camizestrant. AstraZeneca linked switching to its oral SERD to a 56% jump in progression-free survival.
However, the FDA raised questions about the study design and its advisory committee voted six to three that AstraZeneca failed to show camizestrant provides a clinically meaningful benefit. The vote was a blow to AstraZeneca’s hopes of winning approval, although the FDA can go against advisory committees.
After the setback, AstraZeneca provided additional analyses requested by the FDA. The analyses include data on circulating tumor DNA clearance linked to longer-term efficacy outcomes, which AstraZeneca will share next week at the American Society of Clinical Oncology annual meeting. The FDA has pushed back its ruling on whether to approve camizestrant while it reviews the analyses.
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AstraZeneca didn’t provide a new decision date. Three-month delays are typical and, during the second Trump administration, have been a common occurrence. After budget cuts shrank its workforce, the FDA delayed rulings on assets including Bayer’s Lynkuet, Biohaven’s troriluzole and Sanofi’s tolebrutinib. The FDA reportedly blamed a “heavy workload and limited resources” for one delay.
The agency has continued to delay rulings this year, with Biogen, Savara and Travere Therapeutics among the companies to reveal the FDA has extended reviews of their molecules. Like AstraZeneca, those three companies suffered delays after submitting additional information that the agency needed time to review.
If AstraZeneca’s analyses allay the FDA’s concerns, the Big Pharma could win approval for an asset that it has tipped (PDF) to generate peak sales of more than $5 billion. The forecast could survive the failure to win approval based on the switching study, with Guggenheim Securities analysts describing the Serena-6 study as “a limited commercial opportunity in our and [AstraZeneca’s] view” in a note to investors this month.
AstraZeneca is running two adjuvant studies and a trial in a first-line setting as it seeks to establish its drug candidate in multiple parts of the breast cancer care pathway. Roche reported the failure of its rival oral SERD in first-line breast cancer in March, but AstraZeneca executives have argued their trial designs and drug candidate are differentiated.
Last week, Europe’s Committee for Medicinal Products for Human Use blessed camizestrant with a positive opinion. The drug will be marketed as Etcamah in Europe.
