MRTX1719 selectively inhibits MTAP del cancer cell line growth in vitro and in vivo. A and B, MRTX1719 in vitro activity across a panel of MTAP WT and MTAP del cell line models (5-day viability assay, Crown Biosciences). Dot plots showing median with 95% confidence intervals of IC50 values for MRTX1719 (A) and GSK3326595 (GSK-595; B) in MTAP WT and MTAP del cell line models. A smaller cohort of models was tested with GSK-595. Median values: MRTX1719-MTAP del: IC50 = 90 nmol/L; MTAP WT: IC50 = 2.2 mmol/L; GSK-595-MTAP del: IC50 = 262 nmol/L; MTAP WT: IC50 = 286 nmol/L. Statistics were determined using a two-tailed Student t test with significance indicated (*, P < 0.05). C, MRTX1719 was administered orally at the doses indicated to five mesothelioma PDX models. n = 3–5 mice per treatment group. Data, average tumor volume ± SEM. Statistics were determined using a two-way ANOVA with significance indicated (*, P < 0.05). TGI, tumor growth inhibition.