Study of Tazemetostat in Lymphoid Malignancies

This study is testing tazemetostat, a targeted drug that blocks a specific cancer-related enzyme (EZH2), in people with peripheral T-cell lymphoma (a rare type of blood cancer) that has returned or stopped responding to previous treatment. **You may be eligible if:** - You are 18 or older with a confirmed diagnosis of peripheral T-cell lymphoma (one of the specific subtypes listed in the trial) - Your cancer has relapsed or is refractory (didn't respond to prior treatment) - You have received at least one prior treatment for your lymphoma - You have at least one measurable tumor on imaging **You may NOT be eligible if:** - You have not previously been treated for your lymphoma - You have uncontrolled active infections, including uncontrolled HIV or hepatitis C that hasn't been adequately treated - You are pregnant or breastfeeding - You have serious organ dysfunction that makes treatment unsafe Talk to your doctor to see if this trial is right for you.