A RANDOMIZED PHASE IIB STUDY, EVALUATING EFFICACY OF SALVAGE THERAPY WITH BRENTUXIMAB VEDOTIN-ESHAP VS ESHAP IN PATIENTS WITH RELAPSED / REFRACTORY CLASSICAL HODKIN’S LYMPHOMA, FOLLOWED BY BRENTUXIMAB VEDOTIN CONSOLIDATION (INSTEAD OF AUTOLOGOUS HEMATOPOIETIC STEM CELL TRANSPLANTATION) IN THOSE WHO ATTAINED A METABOLIC COMPLETE REMISSION AFTER SALVAGE THERAPY