Tixagevimab-cilgavimab for preventing breakthrough COVID-19 in dialysis patients: a prospective study.

Background: The effectiveness of tixagevimab-cilgavimab as pre-exposure prophylaxis (PrEP) against breakthrough coronavirus disease 2019 (COVID-19) in dialysis patients remains uncertain due to limited data.

Methods: In this multicenter prospective study, we enrolled vaccinated dialysis patients and divided them into two groups: a tixagevimab-cilgavimab group (received a 150 mg/150 mg intramuscular dose of tixagevimab-cilgavimab) and a control group (age-matched patients not receiving tixagevimab-cilgavimab). The primary outcome was the breakthrough COVID-19 rate at 6 months, whereas secondary outcomes included COVID-19-related hospitalization, intensive care unit admission, endotracheal intubation and mortality. The safety of tixagevimab-cilgavimab was assessed.

Results: Two hundred participants were enrolled, with equal numbers in each group ( = 100 each). Baseline characteristics were comparable between groups, except for a higher number of COVID-19 vaccine doses in the tixagevimab-cilgavimab group [median (IQR) 4 (3-5) vs. 3 (3-4);  = .01]. At 6 months, the breakthrough COVID-19 rates were comparable between the tixagevimab-cilgavimab (17%) and control (15%) groups ( = .66). However, the median (IQR) time to diagnosis of breakthrough infections tended to be longer in the tixagevimab-cilgavimab group [4.49 (2.81-4.98) vs 1.96 (1.65-2.91) months;  = .08]. Tixagevimab-cilgavimab significantly reduced COVID-19-related hospitalization rates (5.9% vs 40.0%;  = .02) among participants with breakthrough infections. All tixagevimab-cilgavimab-related adverse events were mild.

Conclusion: The use of tixagevimab-cilgavimab as PrEP in vaccinated dialysis patients during the Omicron surge did not prevent breakthrough infections but significantly reduced COVID-19-related hospitalizations. Further research should prioritize alternative strategies.