Vaccines (Jul 2024)

Real World Use of Tixagevimab/Cilgavimab Pre-Exposure Prophylaxis of COVID-19 in Immunocompromised Individuals: Data from the OCTOPUS Study

  • Alessandra Vergori,
  • Giulia Matusali,
  • Eleonora Cimini,
  • Licia Bordi,
  • Paola Borrelli,
  • Simone Lanini,
  • Roberta Palazzi,
  • Jessica Paulicelli,
  • Davide Mariotti,
  • Valentina Mazzotta,
  • Stefania Notari,
  • Rita Casetti,
  • Massimo Francalancia,
  • Silvia Rosati,
  • Alessandra D’Abramo,
  • Cosmina Mija,
  • Paola Mencarini,
  • Eugenia Milozzi,
  • Emanuela Caraffa,
  • Simona Sica,
  • Elisabetta Metafuni,
  • Federica Sorà,
  • Angela Rago,
  • Agostina Siniscalchi,
  • Elisabetta Abruzzese,
  • Mariagrazia Garzia,
  • Giovanni Luzi,
  • Roberta Battistini,
  • Luca Prosperini,
  • Antonella Cingolani,
  • Enrico Girardi,
  • Fabrizio Maggi,
  • Andrea Antinori

DOI
https://doi.org/10.3390/vaccines12070784
Journal volume & issue
Vol. 12, no. 7
p. 784

Abstract

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Objective. We aimed to report the real-world use and outcomes over time in immunocompromised individuals receiving tixagevimab/cilgavimab (T/C) pre-exposure prophylaxis (PrEP). Methods. This observational study included participants who received T/C PrEP, categorized into three groups: (i) No COVID-19 (NoC), i.e., participants who never had COVID-19; (ii) Hybrids (H), i.e., participants who had COVID-19 before PrEP; and (iii) Break-through Infections (BTIs), i.e., participants who had COVID-19 after PrEP. The study measured several immune markers at the administration of T/C (T0) at 3 (T1), 6 (T2), and 9 (T3) months afterward. These markers included: anti-receptor-binding domain (RBD) IgG antibodies; BA.5-neutralizing antibodies (nAbs); mucosal IgG; and T cell immunity. The incidence rate ratios for BTIs were analyzed using a Poisson regression model. Results. A total of 231 participants with a median age of 63 years (IQR 54.0–73.0). were included. Among these, 84% had hematological diseases and received a median of three vaccine doses. N = 72 participants belonged to the NoC group, N = 103 to the H group, and n = 56 to the BTI group (24%), with most BTIs being mild/moderate. The incidence rate (IR) of BTIs was 4.2 per 100 patient-months (95% CI 3.2–5.4), with no associated risk factors identified. There was a significant increase in anti-RBD IgG levels 3 months after the T/C administration in all groups, followed by a decline at 6 months, whereas at the same time points, geometric mean titers (GMTs) of anti-BA.5 nAbs were low for all groups and were around or below the detection threshold. No significant changes were observed in IFN-γ levels. The mucosal immune response was observed only 3 months after the PrEP administration. Conclusion. We provided a real-world experience model on the clinical efficacy of T/C PrEP in preventing severe COVID-19 during the Omicron wave through a comprehensive virological and immunological study. While waiting for the arrival of new monoclonal antibodies that can effectively neutralize the most recent variants, T/C PrEP remains the only viable strategy in the available armamentarium today to prevent COVID-19 complications in an extremely fragile population with suboptimal immune responses to COVID-19 vaccines.

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