Adverse event reporting of marketed biosimilar and biological monoclonal antibody cancer treatments in the United States.

BACKGROUND

By 8 September 2022, 10 biological monoclonal antibody (mAb) biosimilar products for cancer treatment had been approved and marketed in the United States (US). This study examined adverse event (AE) reporting patterns and disproportionate reporting signals for mAb biosimilars in the US compared to their originator biologics.

RESEARCH DESIGN AND METHODS

The US Food and Drug Adverse Event Reporting System database was used to identify AE reports for biological rituximab, bevacizumab, trastuzumab, and their marketed biosimilars. Proportions of patient age, sex and type of reporters of AEs were described for these reports. Reporting odds ratios (RORs) with 95% confidence intervals were calculated to compare reporting disproportionality in serious, death, and specific AEs between mAb biologics/biosimilars (index) and all other drugs. Breslow-Day statistic was used to determine homogeneity in RORs between each mAb biologic-biosimilar pair at p < 0.05.

RESULTS

We observed no risk signals of serious or death AE reporting for all three mAb biosimilars. A signal of disproportionate reporting of death was detected between biological and biosimilar bevacizumab (p < 0.05).

CONCLUSIONS

Our findings support the similarity in signals of disproportionate AE reporting between mAb originator biologics and biosimilars, except for death between biological and biosimilar bevacizumab.