Fig. 5. Antitumor activity of T-DXd according to mutation in PIK3CA, RAS, and HER2 in ctDNA at baseline and bTMB.

Vertical red dashed line shows the ORR of 45.3% in the overall population for Cohort A. P values are based on two-sided Fisher’s exact test for ORR and those based on two-sided log-rank test for PFS and OS are shown, without adjustment for multiple comparisons. Error bars represent the 95% CI. PIK3CA variants were determined according to published data³⁴. NRAS and KRAS variants were determined as mutation at codon 12, 13, 59, 61, 117, or 146. bTMB ≥ 20 mut/Mb was considered high according to the Guardant Health report. bTMB, blood tumor mutational burden; Mut, mutant; NA, not applicable; ORR, objective response rate; OS, overall survival; PFS, progression-free survival; WT, wild type.