tcsc1758 Tazemetostat

Tazemetostat (EPZ-6438) is a potent, selective and orally available EZH2 inhibitor with K_i and IC₅₀ of 2.5 and 11 nM, respectively.

IC50 & Target: Ki: 2.5 nM (EZH2)^[1]

In Vitro: Tazemetostat (EPZ-6438) inhibits EZH2 in a manner competitive with the substrate S-adenosylmethionine (SAM). Tazemetostat inhibits EZH1, EZH2(in peptide assay), EZH2 (in nucleosome assay) with IC₅₀of 392 nM, 11 nM and 16 nM, respectively. Tazemetostat displays a 35-fold selectivity versus EZH1 and >4,500-fold selectivity relative to 14 other HMTs tested^[1].

In Vivo: Tazemetostat (EPZ-6438, 125 mg/kg) induces tumor stasis during the administration period and produced a significant tumor growth delay compared with vehicle after the dosing period. Measuring Tazemetostat plasma levels either 5 min before or 3 h after dosing on day 21 reveals a clear dose-dependent increase in systemic exposure^[1]. Dose-dependent target inhibition is observed in PBMCs and bone marrow from rats dosed with Tazemetostat (EPZ-6438, orally administered, 100, 300, or 1,000 mg/kg) as measured by ELISA^[2].