Clinical Trial of Brentuximab Vedotin in Classical Hodgkin Lymphoma

This trial will study two treatment combinations for classical Hodgkin lymphoma (cHL). This trial will find out if these two treatment combinations work to treat cHL. It will also find out what side effects occur. A side effect is anything the drug does besides treating cancer. This study will have three parts (Parts A, B, and C). The drugs used in Part A are a combination of targeted anticancer drug (brentuximab vedotin) and three chemotherapy drugs (doxorubicin, vinblastine, and dacarbazine). These four drugs are called "A+AVD." Participants will be treated with granulocyte colony stimulating factor (G-CSF) following every dose of A+AVD for 6 cycles of treatment (12 doses). Part A will look at whether the A+AVD drug combination reduces the number of participants who experience the side effect of febrile neutropenia. Febrile neutropenia is a very low white blood cell count and a fever, which can be life threatening. Parts B and C will use drug combination of brentuximab vedotin, plus nivolumab, doxorubicin, and dacarbazine. These four drugs are called "AN+AD." Parts B and C will study how well the drugs work to treat cHL and what side effects they cause.