Project description:BackgroundPreventive strategies against severe COVID-19 in Inborn Errors of Immunity (IEI) include bivalent vaccines, treatment with SARS-CoV-2 monoclonal antibodies (mAbs), early antiviral therapies, and pre-exposure prophylaxis (PrEP).ObjectiveTo assess the effectiveness of the PrEP with tixagevimab/cilgavimab (AZD7442) in IEI with primary antibody defects during the COVID-19 Omicron wave.MethodsA six-month prospective study evaluated the SARS-CoV-2 infection rate and the COVID-19 severity in the AZD7442 group, in the no-AZD7442 group, and in a group of patients with a recent SARS-CoV-2 infection (< three months). Spike-specific IgG levels were measured at regular intervals.ResultsSix out of thirty-three patients (18%) and 54/170 patients (32%) became infected in the AZD7442 group and in the no-AZD7442 group, respectively. Within 90 days post-administration, the AZD7442 group was 85% less likely to be infected and 82% less likely to have a symptomatic disease than the no-AZD7442 group. This effect was lost thereafter. In the entire cohort, no mortality/hospitalisation was observed. The control group of 35 recently infected patients was 88% and 92% less likely to be infected than the AZD7442 and no-AZD7442 groups. Serum anti-Spike IgG reached the highest peak seven days post-AZD7442 PrEP then decreased, remaining over 1000 BAU/mL 180 days thereafter.ConclusionIn patients with IEI and antibody defects, AZD7442 prophylaxis had a transient protective effect, possibly lost possibly because of the appearance of new variants. However, PrEP with newer mAbs might still represent a feasible preventive strategy in the future in this population.
Project description:The approved combination of Tixagevimab/Cilgavimab has been shown to decrease the rate of symptomatic SARS-CoV-2 infection in patients at increased risk of inadequate response to vaccination. However, Tixagevimab/Cilgavimab was tested in a few studies that included patients with hematological malignancies, even if this population has shown an increased risk of unfavorable outcomes following infection (with high rates of hospitalization, intensive care unit admission, and mortality) and poor significant immunization following vaccines. We performed a real-life prospective cohort study to evaluate the rate of SARS-CoV-2 infection following pre-exposure prophylaxis with Tixagevimab/Cilgavimab in anti-spike seronegative patients compared to a cohort of seropositive patients who were observed or received a fourth vaccine dose. We recruited 103 patients with a mean age of 67 years: 35 (34%) received Tixagevimab/Cilgavimab and were followed from March 17, 2022, until November 15, 2022. After a median follow-up of 4.24 months, the 3-month cumulative incidence of infection was 20% versus 12% in the Tixagevimab/Cilgavimab and observation/vaccine groups respectively (HR 1.57; 95% CI: 0.65-3.56; p = 0.34). In this study, we report our experience with Tixagevimab/Cilgavimab and a tailored approach to SARS-CoV-2 infection prevention in patients with hematological malignancies during the SARS-CoV-2 omicron surge.
Project description:BackgroundWe report spike protein-based lineage and AZD7442 (tixagevimab/cilgavimab) neutralizing activity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants identified from breakthrough infections in the PROVENT preexposure prophylaxis trial.MethodsVariants identified from PROVENT participants with reverse-transcription polymerase chain reaction-positive symptomatic illness were phenotypically assessed to determine neutralization susceptibility of variant-specific pseudotyped virus-like particles.ResultsAt completion of 6 months' follow-up, no AZD7442-resistant variants were observed in breakthrough coronavirus disease 2019 (COVID-19) cases. SARS-CoV-2 neutralizing antibody titers were similar in breakthrough and nonbreakthrough cases.ConclusionsSymptomatic COVID-19 breakthrough cases in PROVENT were not due to resistance-associated substitutions in AZD7442 binding sites or lack of AZD7442 exposure.Clinical trials registrationNCT04625725.
Project description:Therapeutic anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies (MAbs) provide immunosuppressed and vulnerable populations with prophylactic and treatment interventions against coronavirus disease 2019 (COVID-19). AZD7442 (tixagevimab-cilgavimab) is a combination of extended-half-life neutralizing MAbs that bind to distinct epitopes on the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. The Omicron variant of concern carries mutations at >35 positions in the spike protein and has undergone further genetic diversification since its emergence in November 2021. Here, we characterize the in vitro neutralization activity of AZD7442 toward major viral subvariants circulating worldwide during the first 9 months of the Omicron wave. BA.2 and its derived subvariants showed the highest susceptibility to AZD7442, while BA.1 and BA.1.1 showed a lower susceptibility. BA.4/BA.5 had a susceptibility level intermediate between BA.1 and BA.2. Mutagenesis of parental Omicron subvariant spike proteins was performed to establish a molecular model to describe the underlying determinants of neutralization by AZD7442 and its component MAbs. The concurrent mutation of residues at positions 446 and 493, located in the tixagevimab and cilgavimab binding sites, was sufficient to enhance in vitro susceptibility of BA.1 to AZD7442 and its component MAbs to levels similar to the Wuhan-Hu-1+D614G virus. AZD7442 maintained neutralization activity against all Omicron subvariants tested up to and including BA.5. The evolving nature of the SARS-CoV-2 pandemic warrants continuing real-time molecular surveillance and assessment of in vitro activity of MAbs used in prophylaxis against and the treatment of COVID-19. IMPORTANCE MAbs are key therapeutic options for COVID-19 prophylaxis and treatment in immunosuppressed and vulnerable populations. Due to the emergence of SARS-CoV-2 variants, including Omicron, it is vital to ensure that neutralization is maintained for MAb-based interventions. We studied the in vitro neutralization of AZD7442 (tixagevimab-cilgavimab), a cocktail of two long-acting MAbs targeting the SARS-CoV-2 spike protein, toward Omicron subvariants circulating from November 2021 to July 2022. AZD7442 neutralized major Omicron subvariants up to and including BA.5. The mechanism of action responsible for the lower in vitro susceptibility of BA.1 to AZD7442 was investigated using in vitro mutagenesis and molecular modeling. A combination of mutations at two spike protein positions, namely, 446 and 493, was sufficient to enhance BA.1 susceptibility to AZD7442 to levels similar to the Wuhan-Hu-1+D614G ancestral virus. The evolving nature of the SARS-CoV-2 pandemic warrants continuing real-time global molecular surveillance and mechanistic studies of therapeutic MAbs for COVID-19.
Project description:BackgroundTixagevimab-cilgavimab (Tix-Cil) was authorized for prophylaxis against COVID-19 in immunocompromised patients from December 2021 through January 2023. Real-world effectiveness for solid organ transplant (SOT) recipients has been unclear.MethodsWe enrolled 911 SOT recipients into a longitudinal COVID-19 serology study, of whom 381 (42%) received ≥1 dose of Tix-Cil. We collected and analyzed data on incident SARS-CoV-2 infections and antibody kinetics for all patients from January 2022 to March 2023, including periods dominated by Omicron BA and BQ subvariants.ResultsOver 253 ± 131 days of follow-up, there were 324 new-onset SARS-CoV-2 infections: 117 (31%) in Tix-Cil treated and 207 (39%) in Tix-Cil untreated patients (p = .012). In analyses adjusting for demographic, clinical, and COVID-19 exposure factors, any Tix-Cil treatment was associated with lower infection risk (OR 0.52, 95% CI 0.27-0.96, p = .039) throughout the surveillance period including when more resistant BQ.1 and BQ.1.1 subvariants had emerged (12/1/2022 onwards). Among treated patients, receiving a Tix-Cil dose was associated with substantial and sustained increase in anti-spike IgG antibody and angiotensin-converting enzyme 2 binding inhibition levels (Abbott Architect assay) that together also demonstrated association with lower infection risk (p = .042). During the full surveillance period, the frequency of infections requiring hospitalization was low overall (N = 26, 2.9% of the total cohort) and not significantly different between Tix-Cil recipients (N = 12, 3.2% of treated patients) and non-Tix-Cil recipients (N = 14, 2.6% of untreated patients) with unadjusted p = .31 for between-group difference.ConclusionIn a large cohort of SOT recipients, we found that Tix-Cil reduced infection risk even amidst emergent Omicron subvariants. Additionally, the extent of measurable humoral response to Tix-Cil may indicate relative effectiveness. Pre-exposure monoclonal antibody therapy may represent a strategy that will continue to offer clinical benefit for immunocompromised persons who are known to derive limited protection from vaccinations.
Project description:ObjectivesThe identification of the SARS-CoV-2 Omicron variants BA.1 and BA.2 immediately raised concerns about the efficacy of currently used monoclonal antibody therapies. Here, we analyzed the activity of Sotrovimab and Regdanvimab, which are used in clinics for treatment of moderate to severe SARS-CoV-2 infections, and Cilgavimab/Tixagevimab, which are approved for prophylactic use, against BA.1 and BA.2 in a 3D model of primary human bronchial epithelial cells.MethodsPrimary human airway epithelia (HAE) cells in a 3D tissue model were infected with clinical isolates of SARS-CoV-2 Delta, BA.1 or BA.2. To mimic the therapeutic use of mAbs, we added Regdanvimab, Sotrovimab or Cilgavimab/Tixagevimab 6 h after infection. In order to mirror the prophylactic use of Cilgavimab/Tixagevimab, we added this compound 6 h prior to infection to the fully differentiated, pseudostratified epithelia cultured in air-liquid interphase (ALI).ResultsWe observed that Sotrovimab, but not Regdanvimab, is active against BA.1; however, both antibodies lose their efficacy against BA.2. In contrast, we found that BA.2 was sensitive to neutralization by the approved prophylactic administration and the therapeutic use, which is not yet permitted, of Cilgavimab/Tixagevimab.ConclusionImportantly, while the use of Tixagevimab/Cilgavimab is effective in controlling BA.2 but not BA.1 infection, monoclonal antibodies (mAbs) with efficacy against BA.1 are ineffective to reduce BA.2 virus replication in a human lung model. Our data may have implications on the variant specific clinical use of monoclonal antibodies.
Project description:Tixagevimab 150 mg and cilgavimab 150 mg (EVUSHELDTM 150 mg + 150 mg solution for injection; tixagevimab + cilgavimab) is an intramuscular (IM) long-acting monoclonal antibody combination developed by AstraZeneca for the prevention and treatment of COVID-19. In March 2022, tixagevimab + cilgavimab was approved in the UK for pre-exposure prophylaxis of COVID-19 in adults who are not currently infected with SARS-CoV-2 and who have not had a known recent exposure to an individual infected with SARS-CoV-2 and who are unlikely to mount an adequate immune response to COVID-19 vaccination or for whom COVID-19 vaccination is not recommended, and in the EU for the prevention of COVID-19 in adults and adolescents aged ≥ 12 years and weighing ≥40 kg. In December 2021, tixagevimab + cilgavimab was granted Emergency Use Authorization by the US FDA for the pre-exposure prophylaxis of COVID-19 in adults and paediatric individuals (≥ 12 years of age and weighing ≥ 40 kg). This article summarizes the milestones in the development of tixagevimab + cilgavimab leading to this first approval for pre-exposure prophylaxis of COVID-19 in individuals who are not currently infected with SARS-CoV-2.