Mali Barbi, Medical Oncologist at Northwell Health, shared on X:
“We’re all hearing about the camizestrant approval, so here are my two cents.
The FDA cleared it in HR+/HER2- advanced breast cancer for patients who develop an ESR1 mutation in ctDNA on first-line endocrine therapy, before the scan progresses. It cleared because switching at that molecular signal, instead of waiting for radiographic progression, roughly doubled PFS, 16 vs 9.2 months. Accelerated approval, so no survival data yet, and part of that PFS gap may just reflect leaving the control arm on a failing drug.
Where I see it landing: the trigger to change therapy moves from the scan to the blood. That is the real shift, bigger than one drug.
But two practical questions decide whether it works in clinic, and neither is settled.
- How often would I draw the ctDNA? SERENA-6 monitored every two to three months. That is a real testing burden on patients who feel well and look stable on imaging.
- And in whom? You would monitor everyone on first-line AI plus CDK4/6i, but only the fraction who turn ESR1 positive get the drug. In SERENA-6 that meant screening thousands to randomize a few hundred. The burden of testing lands on a much larger group than the treatment does.
So the open question is not really the drug. It is whether serial monitoring of stable patients earns its place, when the testing falls on many and the benefit reaches few. I am not convinced yet.”
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