Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 12 2 2018 04 05 84 91 EN Gholamreza Toogeh Thrombosis Hemostasis Research Center, Tehran University of Medical Sciences, Tehran, IranDepartment of Internal Medicine, Hematology and Medical Oncology Ward, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Mohammad Faranoush Pediatric Growth and Development Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences, Tehran, Iran Seyed Mohsen Razavi Clinic of Hematology and Oncology, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran Hassan Jalaeikhoo AJA Cancer Research Center (ACRC), AJA University of Medical Sciences, Tehran, Iran Abolghasem Allahyari Division of Hematology and Medical Oncology, Emam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Reza Ravanbod Department of Internal Medicine, Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran Fariba Zarrabi Thrombosis Hemostasis Research Center, Tehran University of Medical Sciences, Tehran, Iran Vahid Fallahazad Research Department, Mahak’s Pediatric Cancer Treatment and Research Center, Tehran, Iran Ehsan Rezaei Darzi Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Shadi Sadat Alizadeh Fard School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2017 03 10 2018 01 07 Background: Chronic lymphocytic leukemia (CLL) is characterized by accumulation of B cells in blood, lymphoid tissues and bone marrow. Addition of rituximab to CLL chemotherapy regimens has been associated with improved survival. The aim of this study was to establish efficacy and safety of Zytux™ in comparison to MabThera® in treatment of CLL. Materials and Methods: Seventy CLL patients who met the criteria for entering the study were randomized into two groups (35 patients in each group). Both groups received Fludarabine and Cyclophosphamide plus Rituximab as part of the FCR regimen. Group A was treated with Zytux™, and group B was treated with MabThera®. A non-inferiority margin of 20% for the primary outcome was defined to examine the similarity between Zytux™ and MabThera®. Results: Baseline demographic characteristics showed no statistically significant difference between the two groups. The two treatment groups were comparable in terms of laboratory and clinical findings, cellular index changes and CD (5, 19, 20 and 23) counts during therapy cycles and at the end of the treatment period. Regarding safety results, Zytux™ demonstrated a similar profile of adverse reactions in comparison to MabThera®. Moreover, the overall response rate was 88% and 89% for Zytux™ and MabThera®, respectively (CI -0.17, 0.18). Conclusion: Results showed non-inferiority of Zytux™ in terms of efficacy and adverse events as a biosimilar version of MabThera®.   https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/771 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/771/623