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The following is a summary of “Trajectories and predictive significance of inflammatory parameters for clinical outcome in COVID–19 patients treated with tocilizumab,” published in the August 2024 issue of Infectious Disease by Killer et al.

An approved adjuvant therapy reducing mortality and morbidity in severe cases of COVID-19 through its effects on hyperinflammation is due to IL-6 receptor inhibitor tocilizumab. 

Researchers conducted a retrospective study to depict the changes in patients treated with tocilizumab, evaluate its predictive value for death and bacterial superinfection, and assess its impact on mortality rates.

They analyzed 76 patients treated with tocilizumab for severe COVID-19 in 2020 and 2021. Inflammatory markers (IL-6, C-reactive protein (CRP), procalcitonin) were documented before and up to 7 days after tocilizumab administration.

The results showed an overall mortality of 25%, which rose to 53.8% among patients requiring invasive respiratory support. Patients who died had higher baseline IL-6 levels (P = 0.026) and peak IL-6 levels after tocilizumab compared to survivors (P < 0.0001). A peak IL-6 level exceeding 1000 pg/dl after tocilizumab administration strongly predicted mortality (AUC = 0.812). Additionally, 41.1% of deceased patients had a renewed increase in CRP after an initial drop following tocilizumab, whereas only 7.1% of survivors experienced this (P = 0.0011). Documented bacterial superinfections occurred in 35.5% (27/76) of patients, with 48.1% (13/27) of these patients succumbing to the infection.

They concluded a decline in CRP and an increase in IL-6 after tocilizumab treatment. An increase in IL-6 levels exceeding tenfold of baseline, a peak IL-6 level above 1000 pg/ml, or a renewed rise in CRP were associated with higher mortality. Suppressed CRP synthesis may hinder the diagnosis of bacterial superinfections, thereby increasing the risk of complications.

Source: link.springer.com/article/10.1007/s15010-024-02375-x#Abs1