Information Samotolisib (LY3023414) Samotolisib (LY3023414, GTPL8918) is an oral ATP competitive inhibitor of the class I PI3K isoforms, mTOR and DNA-PK . Targets class I PI3K isoforms ; mTOR kinase ; DNA-PK In vitro LY3023414 shows high solubility across a wide pH range. inhibition of PI3K/AKT/mTOR signaling by LY3023414 causes G1 cell-cycle arrest and resulted in broad antiproliferative activity in cancer cell panel screens. In cell-based assays, LY3023414 inhibition of PI3K and mTOR is assessed in the PTEN-deficient U87 MG glioblastoma cell line. LY3023414 inhibits the phosphorylation ofAKT at position T308 downstream of PI3K at an IC50 of 106 nM. Similarly, LY3023414 inhibits phosphorylation of AKT at position S473 (IC50 = 94.2 nM) by mTORC2 as well as phosphorylation of mTORC1 kinase targets p70S6K (position T389; IC50 =10.6 nM) and 4E-BP1 (positions T37/46; IC50 = 187 nM). The downstream phosphorylation of S6RP at positions pS240/244 (IC50 = 19.1 nM) by p70S6K was inhibited as well, indicating target inhibition along the entire PI3K/AKT/mTOR pathway by LY3023414. In vivo LY3023414 demonstrates high bioavailability and dose-dependent dephosphorylation of PI3K/AKT/mTOR pathway downstream substrates such as AKT, S6K, S6RP, and 4E-BP1 for 4 to 6 hours, reflecting the drug\'s half-life of 2 hours. Intermittent target inhibition is sufficient for its antitumor activity. LY3023414 shows time- and dose-dependent target inhibition in vivo. It is currently being evaluated in phase 1 and 2 trials for the treatment of human malignancies.