To assess the pharmacokinetics (PK) and preliminary in vivo efficacy of YF2, SUDHL-6 (EP300-mutated) xenograft bearing mice were treated once daily i.p. for 6 days with YF2 doses of 40mg/kg or 60mg/kg….It demonstrates selective cytotoxic effects in EP300-mutated DLBCL cell lines, and is both well tolerated and effective in xenograft mouse models of lymphoma suggesting potential clinical application and precision medicine opportunities for patients harboring this mutation.