Chemoradiotherapy With Targeted Immunotherapy in Pediatric Lymphoma

The primary objective is 1) to determine feasibility and safety, as defined by dose limiting toxicities (DLTs), of adding polatuzumab vedotin (Pv) in combination with rituximab (RTX) containing French-American-British (FAB) chemoimmunotherapy, with reduced dose anthracycline, in CAYA with intermediate and high risk newly diagnosed MB-NHL; 2) To define the feasibility and safety, as defined by DLTs, of the addition of nivolumab to the backbone of reduced toxicity chemoimmunotherapy with brentuximab vedotin (Bv), vinblastine, dacarbazine and rituximab, with reduced dose anthracycline, in CAYA with newly diagnosed intermediate and high risk cHL.