Caldito NG, Shirani A, Salter A, Stuve O. Adverse event profile differences between rituximab and ocrelizumab: Findings from the FDA Adverse Event Reporting Database. Mult Scler. 2020;1352458520949986. doi:10.1177/1352458520949986
Background: Rituximab and ocrelizumab are anti-CD20 monoclonal antibodies that have shown a marked reduction in multiple sclerosis (MS) inflammatory activity. However, their real-world safety profile has not been adequately compared.
Objective: To investigate the adverse event (AE) profile of rituximab and ocrelizumab reported to the Food and Drug Administration Adverse Event Reporting System (FAERS) database.
Methods: The FAERS database was filtered by indication (MS) and drug (rituximab or ocrelizumab). Disproportionality analyses including but not limited to reporting odds ratio (ROR) were conducted to identify drug-AE associations. A signal was detected if the lower limit of the 95% confidence interval of ROR (ROR025) exceeded 1.
Results: There were 623 and 7948 reports for rituximab and ocrelizumab, respectively. The most frequent AEs with rituximab and ocrelizumab were infusion-related reaction (4.82%) and urinary tract infection (10.52%), respectively. The strongest drug-AE association for rituximab and ocrelizumab were ear pruritus (ROR025: 47.53) and oral herpes (ROR025: 38.99), respectively. Ocrelizumab was associated with an almost two times higher frequency of infections than rituximab (21.93% vs 11.05%, respectively).
Conclusion: This study revealed differences in reporting AEs between rituximab and ocrelizumab. Infections were reported more frequently with ocrelizumab. Although speculative, a potentially different or more extensive B-cell depletion by ocrelizumab might explain these findings. Additional pharmacovigilance studies need to be performed to better characterize differences in the AE profile in B-cell-depleting therapies.
Why is it speculative? The have not read our paper.,,,, We know that rituximab does not deplete B cells anywhere near as effectively as ocrelezumab. The B cells are probably depleted for about 6 months more, it has a higher a better killing potentual due to enhanced effector activity
The AEs included in the immune system category included hypersensitivity and anaphylactic shock which could indicate a more severe allergic reaction to the rituximab infusion. This is because there is more mouse bits in rituximab than ocrelizumab.
There were more infections reported with ocrelizumab, but we have to remember this a registry for adverse events and the question is what is the demoninator because there clearly a lot more people with MS using ocrelizumab than ritximab and as only ocrelizumab is FDA approved and the records came from the states