Low to undetectable Omicron BQ.1.1 neutralization by patient's sera a month after initiation of AZD7442 600 mg.

In this journal, we recently reported the limited capacity of patients' sera, a month after initiation of 300 mg of AZD7442 (150 mg tixagevimab and 150 mg cilgavimab) as pre-exposure prophylaxis (PrEP), to neutralize the Omicron variant, particularly its BA.1 and BA.5 sublineages. 1 de Lamballerie X. Martin-Blondel G. Dupont A. et al. Low serum neutralization of Omicron variants a month after AZD7442 prophylaxis initiation. J Infect. 2023; 86: 66-117 Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar PrEP was associated in immunocompromised patients to a reduction in the risk of SARS-CoV-2 infection, and of symptomatic and severe COVID-19 in the Omicron BA.1 and BA.2 era. 2 Kertes J. Shapiro Ben David S. Engel-Zohar N. et al. Association between AZD7442 (Tixagevimab-Cilgavimab) administration and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, hospitalization, and mortality. Clin Infect Dis. 2022; ciac625https://doi.org/10.1093/cid/ciac625 Crossref Scopus (18) Google Scholar However, the rate of breakthrough infections increased in some studies after the emergence of the BA.5 sublineage, 3 Davis J.A. Granger K. Roubal K. et al. Efficacy of tixagevimab-cilgavimab in preventing SARS-CoV-2 for patients with B-cell malignancies. Blood. 2023; 141: 200-203 Crossref PubMed Scopus (12) Google Scholar even after AZD7442 dosage was increased to 600 mg (300 mg tixagevimab and 300 mg cilgavimab). The BA.5 sublineage, dominant since September 2022, is currently transitioning to BQ.1.1 in Europe. Approved monoclonal antibodies targeting the Spike protein, including tixagevimab and cilgavimab, have a drastically reduced in vitro neutralization activity on this novel Omicron sublineage. 4 Imai M. Ito M. Kiso M. et al. Efficacy of antiviral agents against omicron subvariants BQ.1.1 and XBB. N Engl J Med. 2023; 388: 89-91 Crossref PubMed Scopus (34) Google Scholar However, the neutralizing activity of sera from AZD7442-treated patients against the BQ.1.1 sublineage remains uncharacterized.