A Phase III, Randomized Study of Nivolumab (Opdivo) Plus AVD or Brentuximab Vedotin (Adcetris) Plus AVD in Patients (Age >/= 12 Years) with Newly Diagnosed Advanced Stage Classical Hodgkin Lymphoma

Primary Objective: To compare the progression-free survival (PFS) in patients with newly diagnosed advanced stage classical Hodgkin lymphoma randomized to N-AVD (nivolumab, doxorubicin, vinblastine, dacarbazine) versus that obtained with BV-AVD (brentuximab vedotin, doxorubicin, vinblastine, dacarbazine). Secondary Objectives: a) To compare overall survival (OS) in patients randomized to N-AVD versus BV- AVD. b) To compare event-free survival (EFS) in patients randomized to N-AVD versus BV-AVD. c) To compare the metabolic complete response (CR) rate at the end of treatment in patients randomized to N-AVD versus BV-AVD. d) To compare the physician-reported treatment-related adverse event rates between arms stratified by age groups. e) To compare patient-reported symptoms using selected PRO-CTCAE items between arms stratified by age groups. f) To compare the safety and tolerability of N-AVD versus that of BV-AVD.