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Kidney Week

Abstract: TH-PO971

Recombinant SARS-CoV-2 Antibodies in Kidney Transplant Recipients Without Neutralizing Antibodies Following Vaccination: The RESCUE-TX Trial

Session Information

Category: Coronavirus (COVID-19)

  • 000 Coronavirus (COVID-19)

Authors

  • Reindl-Schwaighofer, Roman, Medical University of Vienna, Vienna, Austria
  • Heinzel, Andreas, Medical University of Vienna, Vienna, Austria
  • Oberbauer, Rainer, Medical University of Vienna, Vienna, Austria
Background

Pre-exposition prophylaxis (PrEP) with monoclonal antibodies is used to prevent COVID-19 in high-risk individuals. Cilgavimab/tixagevimab remains the only drug approved for PrEP. A reduced efficicacy against Omicrion BA.1 has been reported.

Methods

We started the RESCUE-TX trial in kidney transplant recipients not responding to SARS-CoV-2 vaccination in April 2022. n=194 patients were enrolled and received 300 mg of cilgavimab/tixagevimab (i.m.). Patients are followed at the outpatient department of the Medical University of Vienna after 2, 4, 8, 12, 24, 36 and 48 weeks after dosing including blood draw for drug level quantification (PPD diagnostics; primary endpoint) and SARS-CoV-2 neutralization testing (secondary endpoint). Additional secondary outcomes include the rate and severity of breakthrough infections compared to the overall transplant population not receiving PrEP.

Results

A total of 34 individuals tested positive for SARS-CoV-2 infection following PrEP with cilgavimab/tixagevimab over a 12 week follow-up period (17.5%): Importantly, none of the participants suffered from severe COVID-19. The majority of breakthrough cases were due to the Omicron BA.2 variant. SARS-CoV-2 Omicron BA.2 neutralization tests in a subgroup of 30 patients confirmed strong activity for 12 weeks after PrEP (Figure 1). BA.2 neutralization titers were 160 [Q1, Q3: 120, 220], 160 [Q1, Q3: 120, 220], 120 [Q1, Q3: 80, 150] and 80 [Q1, Q3: 60, 120] at two, four eight and twelve weeks, respectively [Figure 1].

Conclusion

One in six patients tested positive for SARS-CoV-2 after PrEP with cilgavimab/tixagevimab over a 12-week follow-up period in a population with Omicron BA.2 pre-dominance. However, most cases were asymptomatic/oligosymptomatic individuals performing routine PCR testing. In-vivo neutralization capacity was present in all tested individuals for at least 12 weeks.