Fig. 4

Assessment of PCO response to EGFR inhibition. (a) Representative brightfield images of therapeutic resistance of KRAS^A146V MC4 with persistent growth of control and panitumumab from 0 to 48 h in contrast to (b) RAS^WT MR3 with growth arrest assessed by normalized Δ diameter at the organoid level. (c) Pooled analysis of diameter for four independent lines predicted for resistance to EGFRi: RAS^MT (LR2, MR11, MC4) and BRAF^V600E (MC5A) at 48 h (left panel) and change in diameter at 48 h (right panel) by assessment of individual PCOs normalized to baseline diameter at 0 h with corresponding effect size across distributions (GΔ). (d) Pooled analysis of diameter for nine independent RAS^WT/BRAF^WT PCOs at 48 h (left panel) and change in diameter at 48 h (right panel) by assessment of individual PCOs normalized to baseline diameter at 0 h with corresponding effect size across distributions (GΔ). (e) Line-specific sensitivity plotted by effect size (GΔ) including RAS^WT/BRAF^WT (gray) compared against RAS^MT (red) and BRAF^V600E (violet) using student’s t-test for effect size of normalized Δ diameter. (f) MR3 PCO response of single agent EGFR inhbition (panitumumab) *denoted in (e) represents a prospective clinical assessment tracked on CT scan at a 15-week follow-up showing local disease control at the biopsy site and a non-target progression in the right upper lung. Green lines indicate longest diameter (LD) of adrenal metastasis at baseline and restaging and measurements of non-target disease progression in right lung.