Infusion Related Hypersensitivity Reactions with Bio-similar Anti CD-20 Monoclonal Antibody Rituximab in Indian Patients: A Retrospective Study

There is paucity of data on infusion related hypersensitivity reactions (IRHR) pattern of bio-similar rituximab in B-cell lymphoma patients. As bio-similar molecules are independently developed monoclonal antibodies, they are likely to differ in immunogenicity and therefore, the hypersensitivity data of the innovator rituximab may not be directly applicable to patients treated with the biosimilar rituximab molecule. We analysed our data of 256 patients of B cell lymphoid neoplasm who received bio-similar rituximab (Reditux) based chemo-immunotherapy for their treatment. Total 56/256 (21.8%) patients had ≥ grade II IRHR with first dose of rituximab. Grade II reactions were seen in 32/256 (12.5%) cases, grade III and grade IV reactions were seen in 21/256 (8.2%) and 3/256 (1.2%) cases, respectively. Rituximab was withdrawn from all further therapy in only 2 patients due to grade IV IRHR after attempting re-challenge of the drug under intensive monitoring. There was no difference in complete response rates in patients with or without IRHR during their first rituximab infusion. The IRHRs with bio-similar rituximab noted in our study were comparable with the previously published reactions associated with the original rituximab.