Tocilizumab linked to elevated risk for some types of infection
medwireNews: Findings from a multi-database study suggest that rheumatoid arthritis (RA) patients treated with tocilizumab do not have a higher overall risk for serious infection than those treated with tumor necrosis factor (TNF) inhibitors, but their risk for certain types of infection may be elevated.
Seoyoung Kim (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and co-researchers used three US claims databases to analyze data from 39,829 RA patients who initiated treatment with tocilizumab or a TNF inhibitor during 2010–2015, after prior use of least one biologic DMARD or tofacitinib.
Over an average follow-up of 0.9 years, the 13,102 patients initiating tocilizumab experienced 618 serious infections – defined as a bacterial, viral, or opportunistic infection requiring hospitalization – while the 26,727 propensity score-matched patients initiating a TNF inhibitor experienced 1155 serious infections.
These findings translated into comparable overall incidence rates of 4.68 and 3.99 per 100 person–years, respectively, report Kim and team in the Annals of the Rheumatic Diseases.
However, they found that the risk for serious bacterial infection was significantly elevated among patients treated with tocilizumab versus TNF inhibitors, with incidence rates of 3.95 versus 2.97 per 100 person–years (hazard ratio [HR]=1.19).
Tocilizumab-treated patients also had significantly higher rates of skin and soft tissue infections (0.28 vs 0.12 per 100 person–years; HR=2.38) and diverticulitis (0.52 vs 0.21 per 100 person–years; HR=2.34) than those taking TNF inhibitors, but the researchers note that “the absolute risks in both groups were small.”
They say that in spite of the elevated risk for certain types of infection in tocilizumab-treated patients, the similar overall risk for serious infection among the groups “was possibly due to the additional [serious infections] included in the primary endpoint definition that were not evaluated separately, and because more prevalent types of [serious infections] were not different between [tocilizumab] and TNF [inhibitors].”
The researchers also compared serious infection risk among patients initiating treatment with tocilizumab versus abatacept, finding that overall rates were significantly higher among patients given tocilizumab, at 4.51 versus 3.24 per 100 person–years (HR=1.40).
The risk for serious bacterial infection, diverticulitis, pneumonia/upper respiratory tract infection, and septicemia/bacteremia was also significantly higher among patients in the tocilizumab group than those in the abatacept group.
“This head-to-head comparative safety information between [tocilizumab] and TNF [inhibitors] or abatacept may help better manage patients with RA in clinical practice,” say the study authors.
They caution, however, that the databases did not include information on potential confounders such as RA duration and severity, BMI, smoking, and alcohol consumption.
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