Early tocilizumab treatment was associated with survival benefits in hospitalized kidney transplants with severe COVID-19 infection: A prospective cohort study.

Background: The potential of Tocilizumab (TCZ) in preventing the cytokine storm caused by COVID-19 infection has been observed, while the survival benefits were inconclusive in solid-organ transplant recipients. We aimed to explore whether the timing of TCZ administration holds significance in the clinical course of COVID-19 infection and identify predicative factors of TCZ efficacy.

Methods: We conducted a prospective cohort study between December 2022, and January 2023. Early TCZ use referred to administration within 6 days after symptoms onset, while late TCZ use indicated administration after 6 days. The primary endpoint was 30-day mortality.

Results: Twenty-seven kidney transplant recipients with severe COVID-19 infection were enrolled, with 10 in the early use group and 17 in the late use group. In the early use group, ferritin, lactate dehydrogenase (LDH), C-reactive protein (CRP) and brain natriuretic peptide(BNP) levels had shown significant inhibitions comparing to the late use group, and those inflammatory cytokines demonstrated a noticeable decreasing trend after TCZ administration, whereas only CRP levels decreased in the late use group. The Kaplan-Meier survival curve demonstrated that the early use group had a higher likelihood of survival (P = 0.0078). Receiver Operating Characteristic (ROC) analyses revealed that the time from symptoms to TCZ use (AUC: 0.645), LDH (AUC: 0.803), CRP (AUC: 0.787), and IL-6 (AUC: 0.725) were potential predictive factors of TCZ efficacy. TCZ use within 6 days from symptoms onset, with CRP < 73.5 mg/L, LDH < 435.5 IU/L, and IL-6 < 103.5 pg/mL, had higher survival rates (P = 0.008, P = 0.009, P < 0.001, P < 0.001).

Conclusion: This study highlights the survival benefits of early TCZ use and the predicative role of cytokines levels in predicting TCZ efficacy in kidney transplant recipients with severe COVID-19 infection.