The Case for First-Line Therapy and Understanding TROP2 as a Target

The panel discusses the rationale for using effective agents in the first-line metastatic setting rather than reserving them for later lines, considering the disease's aggressive course and limited expected survival alongside the trajectories seen in other breast cancer subtypes. Panelists highlight attrition data showing that a substantial proportion of patients may not reach second-line therapy, a consideration particularly relevant for patients relapsing after early-stage chemoimmunotherapy. The discussion then turns to TROP2 as an ADC target, unpacking its broad expression across breast cancers and comparing two agents at the molecular level, including their distinct linkers, payloads, and drug-to-antibody ratios, while emphasizing that clinical data should guide use. Panelists also explain why TROP2 expression does not appear to predict ADC benefit and is not currently used to guide treatment, cautioning against over-interpreting NGS panel reports. Viewers come away understanding both the considerations around front-line therapy and the current limits of biomarkers.