RecruitingPhase 2ProcedureDuvelisib Maintenance for the Treatment of Peripheral T-Cell LymphomasThis phase II trial tests how well duvelisib works as treatment that is given to help keep cancer from coming back after it has disappeared following the initial therapy (maintenance) for patients with peripheral T-cell lymphomas. Duvelisib is in a class of medications called kinase inhibitors. It works by blocking the signals that cause cancer cells to multiply. This helps to stop the spread of cancer cells.