BACKGROUND
The safety and efficacy of biosimilars are carefully reviewed by the Food and Drug Administration (FDA) to ensure the biosimilar meets the high standards for approval. However, safety concerns from infusion nursing staff prompted a review of rituximab-PVVR and rituximab for any new trends in National VA, primary literature, and facility adverse events.
METHODS
Utilizing the VA ADERS (Veteran’s Affairs Adverse Drug Event Reporting System), data was analyzed from 01/01/21 thru 04/01/23. No clear trends were identified to support an increased reaction rate for Rituximab-PVVR or Rituximab. A total of 104 Rituximab product (both parent and biosimilar products) adverse reactions were reported nationally. Of those reported, about half 56 ADEs (54%) were specifically to Rituximab-PVVR.
RESULTS
Reviewing our facility specific VA ADERS data, Birmingham VA reported 7 ADEs. Similarly other sites reported a range of 0 to 13 Rituximab product ADEs. The total number of unique patients to receive a rituximab product in the Birmingham VA since 2021 is 106, resulting in an overall incidence rate of 6.6%.
DISCUSSION
Based on the recent publication, Safety of switching between rituximab biosimilars in onco-hematology “adverse events were similar, in terms of seriousness and frequency, to those described in the literature, providing further support to the clinical safety of biosimilars.” This prospective clinical trial published in 2021, reported grade 1 rituximab related infusion events in 7.1% of patients (n=83) which correlates closely to the reported incidence at our facility referenced above (6.6%). Our current pre-medications include acetaminophen, an antihistamine, and steroid 30 minutes prior to infusion. Although our interdisciplinary team deemed this appropriate, to improve and minimize infusion reaction symptoms, the following interventions were instituted including changing ORAL Diphenhydramine to intravenous Diphenhydramine 25mg IV and providing education to infusion nursing staff on the safety and efficacy of the rituximab and biosimilar products.
CONCLUSIONS
Following the intervention (04/07/23), 36 total unique patients received rituximab products with zero incidents reported. Although the results are limited, the data may suggest IV diphenhydramine reduces the severity of ADEs which may alter reporting or show a potential “nocebo” effect could be a factor with any rituximab infusion needing further evaluation.