The Food and Drug Administration has delayed an approval decision on an experimental breast cancer pill its developer, AstraZeneca, views as a future blockbuster.
AstraZeneca said Wednesday that U.S. regulators extended their review deadline to assess additional data provided by the company, but haven’t yet assigned a new date. That new information includes an analysis to be presented at the American Society of Clinical Oncology meeting on June 2 and that links the performance of the drug, known as camizestrant, to “long term efficacy outcomes,” the company said.
“We look forward to continuing the dialogue with the FDA in order to bring the benefits of camizestrant with this innovative treatment strategy to eligible patients in the U.S. as quickly as possible,” said Susan Galbraith, AstraZeneca’s head of oncology and hematology R&D, in a statement.
Camizestrant is part of a new wave of oral medicines that aim to supplant fulvestrant, a decades-old, injectable breast cancer treatment. Three of these “selective estrogen receptor degraders,” or SERDs, are now available for certain people with HR-positive, HER2-negative breast tumors. AstraZeneca wants to make camizestrant the fourth, and has spotlighted it as a key contributor to its plan to reach $80 billion in annual sales by 2030. Executives have predicted sales could top $5 billion per year.
The outlook for oral SERDs is somewhat uncertain. All three marketed drugs are only cleared for patients with “ESR1” mutations known to help tumors develop resistance, and they haven’t yet proven beneficial as an initial treatment. AstraZeneca, though, has claimed camizestrant touts some different characteristics than other, similar medicines. It has multiple studies underway in early lines of care.
The company has been hoping camizestrant might first get to market in what would be a new kind of treatment setting. In the “SERENA-6” study supporting its application, participants already on two medicines either stayed on the same regimen or swapped out one — a hormone treatment — for camizestrant. The group that received camizestrant had a 56% reduction in the risk of disease progression or death.
Yet, on April 30, an FDA advisory committee found the evidence supporting camizestrant’s benefits in that setting inconclusive and requested additional data. The FDA doesn’t have to follow the guidance of its expert panels, but usually does.
Breast cancer experts recently polled by Leerink Partners analyst Andrew Berens have similarly critical views. In a Wednesday client note, Berens wrote that these specialists were skeptical of a U.S. approval and don’t believe there’s been “sufficient data generated to merit the regimen's use.”
AstraZeneca did, however, receive an endorsement from Europe’s drug regulator last week. Once available there, it’ll be marketed under the name Etcamah.
