A Real-World Experience in Pan-Tumor Testing for HER2 IHC in More Than 65 000 Solid Tumors
jamanetwork.com/journals/jam…
Trastuzumab deruxtecan-nxki (T-DXd) received tumor-agnostic FDA approval in April 2024 for adults with unresectable or metastatic HER2-positive (IHC 3+) solid tumors lacking other treatment options, based on responses seen across three DESTINY trials. This prompted widespread HER2 IHC testing across tumor types, leading to the first large-scale report on real-world HER2 IHC 3+ prevalence using standardized interpretation criteria. Among over 65,000 tested patients, HER2 IHC 3+ rates varied widely by cancer type, with
#BladderCancer showing the highest prevalence (13.9%), while others—like gliomas, sarcomas,
#ProstateCancer, and kidney cancers—had minimal or no expression.
These findings suggest universal HER2 testing may not be necessary for all solid tumors, and a more targeted approach—initiating HER2 IHC only after identifying ERBB2 amplification or overexpression via comprehensive genomic profiling—could reduce unnecessary testing while optimizing workflow and cost-efficiency.
Dave Bryant
Rebecca Feldman
Farah Abdulla
Daniel Magee
Jennifer R. Ribeiro
Matthew Oberley
Milan Radovich
David Spetzler
@carisls
@GeorgeSledge51