I. Assess the safety and tolerability of cyclophosphamide, doxorubicin, etoposide, prednisone, and brentuximab vedotin (CHEP-BV), as induction therapy in patients with CD30-positive peripheral T-cell lymphoma (PTCL). (Safety lead-in) II. Assess the anti-lymphoma activity of CHEP-BV as induction treatment in patients with CD30-positive PTCL. (Phase 2)