Open-Label, Multicenter, Two-Part, Phase 1 Study to Characterize Effects of a Moderate CYP3A Inhibitor on PK of Tazemetostat, Effects of Tazemetostat on PK of CYP2C8 and CYP2C19 Substrates, and Effect of Increased Gastric pH on PK of Tazemetostat in B-cell Lymphoma or Advanced Solid Tumor Patients

Tazemetostat is a selective oral small molecule inhibitor of EZH2

200mg will be orally administered QD for 4 days in order to determine CYP3A4 inhibition when administered concomitantly with tazemetostat

Using omeprazole as a probe substrate, 20mg will be orally administered for a total of 5 days in order to determine the potential of tazemetostat to inhibit or induce CYP2C19. Omeprazole is also being used to determine the effect of increased gastric pH on metabolism of tazemetostat.

Using repaglinide as a probe substrate, 25mg will be orally administered for a total of 2 days in order to determine the potential of tazemetostat to inhibit or induce CYP2C8.