MRTX1133 sensitivty across the PRISM cohort of cell lines.

Supplementary Table S1 details the efficacy of MRTX0902 in a panel of cancer cell lines.

Supplementary Table S2 shows the antitumor activity of MRTX0902 and adagrasib in a panel of human KRAS G12C-mutant tumor cell line-derived and patient-derived xenograft models.

Supplementary Table S5 details the antitumor activity of MRTX0902 and avutometinib in human KRAS-MAPK pathway mutant tumor cell line-derived xenograft models.

Supplementary Figure S4 shows levels of KRAS-MAPK pathway modulation associated with coadministration of MRTX0902 and adagrasib in the MIA PaCa-2 (KRAS G12C-mutant) model.

Supplementary Figure S6 details the improved antiproliferative activity observed with the MRTX0902/osimertinib combination in EGFR mutant models, PC9 (EGFR ex19del) and NCI-H1975 (EGFR L858R/T790M).

Supplementary Figure S5 shows levels of KRAS-MAPK pathway modulation associated with coadministration of MRTX0902 and adagrasib in the murine CT26 (KRAS G12C-mutant) model.

Supplementary Figure S3 details the antitumor effects and gene set enrichment analysis data associated with coadministration of MRTX0902 and adagrasib in KRAS G12C-mutant human tumor xenograft models.

Supplementary Materials and Methods section includes detailed protocols for the following: Experimental Preparation of MRTX0902 and Avutometinib, SOS1 Biochemical Binding Assay, SOS1 and SOS2 Functional Assays, KRAS-SOS1 Protein-Protiein Interaction (PPI) HTRF Assay, In-Cell Western Assay, 3D Ultra-Low Attachment (ULA) Viability Assay, Immunoblotting and Densitometry Analysis, DUSP6 Quantification from Naive and Tumor-Bearing Mouse Blood, Bioanalysis and Pharmacokinetic Analysis, Synergy Analysis, CRISPR/Cas9 Screening and Data Analysis Methodology, RNAseq Pre-Processing, RNAseq Data Analysis, and Whole Genome Sequencing.

Genetic and copy number variants at resistance to adagrasib or sotorasib across the novel cohort of PDAC and GI cancer patients.

Supplemental Table 5A: Drug sensitivity metrics from MRTX1133-treated KRASG12D patient-derived organoids. Supplemental Table 5B: MRTX1133 dose response across KRASG12D mutated patient-derived organoids.

Supplementary Table S3 displays the various genetic co-alterations present in human KRAS G12C-mutant tumor cell line-derived and patient-derived xenograft models evaluated.

Supplemental Table 4A: Differential gene expression analysis between MRTX1133 sensitive and resistant KRASG12D cell lines. Supplemental Table 4B: Analysis of Copy number and RPPA datasets between MRTX1133 sensitive and resistant KRASG12D cell lines.

Supplementary Figure S7 shows the improved antiproliferative activity observed with the MRTX0902/avutometinib combination in KRAS-MAPK pathway mutant models, LN229 (PTPN11 A72S) and NCI-H1435 (NF1 K615N).

Supplementary Figure S8 details the antitumor effects associated with coadministration of MRTX0902 and adagrasib in the MIA PaCa-2 (KRAS G12C-mutant) model.

Supplementary Figure S2 shows the antitumor activity of MRTX0902 in the LN229 (PTPN11 A72S-mutant) model, with tumor growth inhibition data displayed in Figure S2A and ERK phosphorylation graphed in Figure S2B.

Background:Despite advances in treatment, brain metastasis (BM) management remains a significant challenge. Adagrasib is a brain-penetrant KRASG12C inhibitor active in patients with BM. KRAS mutations are linked with immune escape and may contribute to the limited clinical benefit from single-agent immune checkpoint inhibitors (ICI) targeting PD-1/PD-L1 in BM. Although adagrasib sensitizes extracranial tumors to ICI, its intracranial benefit combined with immunotherapy remains unknown. Here, we evaluate adagrasib with ICI in mouse models that mimic the BM immune microenvironment. Methods:We tested the in vitro efficacy of adagrasib on two KrasG12C-mutant murine cancer cells: colorectal CT26G12C and lung cancer KPARG12C. Murine BM models resembling the immunologic characteristics of BM were established by subcutaneous and intracranial injection of these cells. Animals were treated with adagrasib combined with anti-PD-1 and monitored for intracranial tumor growth and survival. Disease-free mice after 11-13 weeks were rechallenged with a higher tumor cell dose to assess tumor-specific memory. Results:Three-week adagrasib monotherapy and combination therapy with ICI demonstrated benefit in colorectal and lung cancer BM models. Adagrasib alone and in combination demonstrated similarly potent anti-tumor effects against extracranial tumors. While monotherapies reduced intracranial tumor growth, adagrasib with ICI showed the most favorable outcome. Although both adagrasib monotherapy and combination therapy extended survival, long-term intracranial disease control after rechallenge was the greatest with combination therapy. Conclusions:Adagrasib with ICI improved long-term survival and blocked CNS progression in dual extra- and intracranial BM models.  These findings support investigation of adagrasib with ICI in patients with KRASG12C-mutant BM.

Supplemental Figure 1: Acquired resistance to KRASG12C inhibition in PDAC and other GI cancers. Supplemental Figure 2: MRTX1133 sensitivity across KRASG12D mutant in vitro models of PDAC. Supplemental Figure 3: Isogenic models of acquired resistance to MRTX1133. Supplemental Figure 4: In vivo treatment and tumor monitoring for the KPC PDAC mouse model. Supplemental Figure 5: Genomic characterization of KPC tumors. Supplemental Figure 6: snRNA-seq quality metrics and description of the tumor microenvironment. Supplemental Figure 7: Identification and characterization of malignant cell populations. Supplemental Figure 8: Characterization of malignant metaprograms in KPC tumors. Supplemental Figure 9: Treatment with MRTX1133 induces modest changes in the immune microenvironment following tumor regression. Supplemental Figure 10: Treatment of 6694C2-LM tumors with MRTX1133 reduces granulocytes but has little effect on T cells. Supplemental Figure 11: Neoadjuvant and adjuvant therapy in a metastatic model of PDAC.