Tixagevimab/Cilgavimab: Still a Valid Prophylaxis against COVID-19 New Variants?

Abstract

BACKGROUND:

this study aims to evaluate the efficacy of tixagevimab/cilgavimab (Evusheld™) against various SARS-CoV-2 variants, including newer Omicron sublineages, in an immunocompromised cohort and in vitro.

STUDY DESIGN:

Conducted in Italy, this research involves immunocompromised patients who received Evusheld. It evaluates serum neutralization activity against different SARS-CoV-2 strains (20A.EU1, BA.5, BQ.1, XBB.1.5, XBB.1.16, and EG.5) before (T0), after 14 (T1), and after 30 (T2) days from the tixagevimab/cilgavimab injection. Furthermore, the in vitro activity of Evusheld against SARS-CoV-2 VOCs was evaluated.

RESULTS:

The cohort was composed of 72 immunocompromised patients. The serum neutralizing activity of tixagevimab/cilgavimab-treated patients was notably lower against newer variants such as BQ.1, XBB.1.5, XBB.1.16, and EG.5. Then, the in vitro study detailed specific EC50 values to quantify the activity of tixagevimab/cilgavimab against various SARS-CoV-2 VOCs. Newer variants like BQ.1 and XBB.1.5 exhibited notably lower neutralization, underscoring the challenges in effectively countering the evolving virus. Interestingly, tixagevimab/cilgavimab maintained reduced but still valid activity against EG.5 with an EC50 of 189 ng/mL and Cmax/EC90 of 110.7.

CONCLUSIONS:

Tixagevimab/cilgavimab efficacy wanes against novel subvariants. This underscores the critical need for ongoing adaptation and vigilance in prophylactic strategies to effectively counter the dynamic and unpredictable nature of the COVID-19 pandemic.

• Authors: Anna Gidari, Samuele Sabbatini, Sabrina Bastianelli, Sara Pierucci, Chiara Busti, Elisabetta Svizzeretto, Andrea Tommasi, Carlo Pallotto, Elisabetta Schiaroli, Daniela Francisci
• Journal: Viruses (Viruses) Vol. 16 Issue 3 (Feb 25 2024) ISSN: 1999-4915 [Electronic] Switzerland
• PMID: 38543720 (Publication Type: Journal Article)

Chemical References

• tixagevimab
• cilgavimab
• Antibodies, Monoclonal

Topics

• Humans
• COVID-19 (prevention & control)
• SARS-CoV-2 (genetics)
• Pandemics
• Antibodies, Monoclonal