Clinical Study to Compare the Efficacy and Safety of Rituximab Biosimilar HLX01 and Rituximab in Combination With CHOP, in Previously Untreated Subjects With CD20+ DLBCL

Inclusion Criteria: * Untreated CD20-positive DLBCL confirmed. * IPI score of 1 to 2, Stage I \~ IV, Score 0 needs to accompanied by bulky disease, which is defined as the presence of a tumor mass with a diameter of more than 7.5 cm. * ECOG performance status of 0 to 2. * More than 6 months life expectancy. * At least one measurable lesion: For nodal tumor mass, more than 1.5 cm in the long axis and more than 1.0 cm in the short axis; For extranodal tumor mass, more than 1.0 cm in the long axis. * 18 years to 70 years; Male or female patients. Exclusion Criteria: * Known allergic reactions against human or murine monoclonal antibody, murine products, or foreign proteins. * Known allergic reactions against any component of CHOP regimen. * Previous treatment for NHL, including chemotherapy, immunotherapy, partial radiotherapy for lymphoma, monoclonal antibody therapy or surgical treatment (excluding lymph node biopsies and surgical resection for non-lymphoma lesions). * History of cytotoxic drugs treatment or anti-CD20 monoclonal antibody treatment for other disease (e.g., rheumatoid arthritis). * Prior use of any monoclonal antibody within 3 months. * Primary central nervous system(CNS) lymphoma, secondary CNS involvement, grey zone lymphoma (GZL) between burkitt and DLBCL, primary effusion lymphoma, plasmablastic lymphoma, primary cutaneous DLBCL, anaplastic lymphoma kinase(ALK) positive DLBCL or transformed lymphoma.