PKMYT1-IN-13 is a potent, orally active, and highly selective PKMYT1 inhibitor. It exhibits an IC50 value of less than 10.0 nM for PKMYT1 in ADP-Glo assays and 19.9 nM in NanoBRET cell assays, demonstrating significant selectivity over WEE1. This compound shows selective antiproliferative activity in CCNE1-amplified cells with minimal impact on wild-type cells. Furthermore, PKMYT1-IN-13 demonstrates notable antitumor activity in HCC1569 mouse xenograft models and is applicable for studying CCNE1-amplified cancers such as gastric, ovarian, and breast cancers.

CDK1:8.7 nM

PKMYT1-IN-13 (compound 20) demonstrates potent antiproliferative activity in CCNE1-amplified cell lines, specifically HCC1569, MKN1, OVCAR-3, AsPc-1, SW837, SW1463, and DLD-1 FBXW7 -/-), with IC50 values of 29.4, 32.8, 43.5, 83.5, 45.9, 87.8, and 328.5 nM, respectively, while showing minimal inhibitory effect on the corresponding wild-type control cells (IC50 of 13672 nM for SK-OV-3 cells and IC50 > 25000 nM for DLD-1 parental cells). In HCC1569 cells, PKMYT1-IN-13 (2-hour treatment) inhibits CDK1 phosphorylation at the Thr14 site, with an IC50 of 8.7 nM. It features favorable safety characteristics, including low CYP inhibition, time-dependent inhibition (TDI), and minimal hERG activity, and achieves high kinase selectivity with an S (10) score of 0.03 in a panel screening of 217 kinases.

In an HCC1569 xenograft mouse model, PKMYT1-IN-13 (compound 20) demonstrates dose-dependent antitumor activity at dosages of 10 and 20 mg/kg, administered orally twice daily for 26 consecutive days.