Prednisone Recruiting Phase 1 / 2 Trials for Aggressive Non-Hodgkin Lymphoma / Diffuse Large B-Cell Lymphoma Unclassifiable / Intravascular Large B-Cell Lymphoma / Primary Mediastinal (Thymic) Large B-cell Lymphoma / T-Cell/Histiocyte-Rich Large B-Cell Lymphoma / CD20 Positive / Transformed Follicular Lymphoma to Diffuse Large B-Cell Lymphoma / B-cell Non-Hodgkin's Lymphomas Treatment