A Study of Brentuximab Vedotin + Adriamycin, Vinblastine, and Dacarbazine in Pediatric Participants With Advanced Stage Newly Diagnosed Hodgkin Lymphoma

The drug being tested in this study is called brentuximab vedotin. Brentuximab vedotin is being tested to treat pediatric participants who have advanced stage, newly diagnosed, classical CD30+ HL. This study will assess the safety, tolerability, and anti-tumor activity, as well as recommended dose of brentuximab vedotin in combination with a multiagent chemotherapy regimen that is based on a current standard of care (SOC) first-line treatment regimen for newly diagnosed HL. The study will enroll approximately 55 evaluable participants. The study will be conducted in 2 phases, Phase 1 and Phase 2. Phase 1 study will enroll at least 6 participants to determine the recommended dose. Once the recommended dose is identified additional participants will be enrolled into phase 2 so that the total number of evaluable participants will be at least 55, including participants treated at recommended dose in Phase 1. Participants will be enrolled to the following initial dose cohort with an option to explore a reduced dose cohort at 36 mg/m\^2 if needed: • Brentuximab vedotin 48 mg/m\^2 in combination with doxorubicin, vinblastine, and dacarbazine. This multi-center trial will be conducted in the United States, Italy, Brazil and Japan. The overall time to participate in this study is approximately 55 months, including the follow-up period. Participants will be followed for a maximum of 30 days following the last dose of protocol therapy for a follow-up assessment and will be followed for survival and disease status every 12 weeks for 12 months, and then every 24 weeks until death or study closure or for up to 2 years from the date of the last participant enrolled.