205P Nirogacestat pediatric compassionate use program: Cross-sectional data review

with recognised driver biology, showing ORRs of 44-94%, whereas alterations without proven relevance in sarcoma produced 0% ORR and only occasional SD.Conclusions: Meaningful activity in sarcoma within basket trials emerged almost exclusively when the molecular alteration represented a validated oncogenic driver for that histotype (NTRK in IFS, KIT in GIST, or IDH1 in chondrosarcoma).These findings demonstrate that histology-agnostic matching is insufficient in sarcoma, where therapeutic effect depends on underlying tumour biology rather than the presence of a biomarker alone.Precision oncology for sarcoma therefore requires driver-defined, biology-anchored strategies rather than extrapolation of pan-cancer biomarkers or agnostic trial designs.