FDA documents reviewed for Revolution Medicines’ Rasonque flagged new scrutiny around KRAS subgroup efficacy, according to investor-focused reporting. The disclosure added pressure on the company’s near-term outlook as analysts reassessed whether response is sufficiently broad across the intended biomarker-defined population. While Rasonque’s overall clinical story remains intact, the market reaction reflected heightened focus on subgroup consistency and the statistical defensibility of the biomarker-defined benefit. This is the kind of review detail that can shift commercial expectations well before confirmatory datasets arrive. For biotech operators, the case underscores how regulator attention to KRAS strata and baseline risk can drive follow-on questions on trial design, endpoint handling, and label-ready breadth.