Precision oncology has transformed cancer treatment by linking molecular features to therapies that can produce large and durable benefits. Imatinib in BCR::ABL1-positive chronic myeloid leukemia, trastuzumab in human epidermal growth factor receptor 2–positive breast cancer, osimertinib in EGFR-mutant non–small cell lung cancer, and larotrectinib in NTRK fusion–positive cancers are canonical examples.1–5 Across a broader evidence base, a meta-analysis of 570 phase II studies involving 32,149 patients found that biomarker-selected strategies were associated with higher median response rates (31% v 10.5%) and longer median progression-free survival (5.9 v 2.7 months) than nonselected strategies.6 These achievements establish molecular enrichment as a powerful approach to drug development and treatment selection.
