Covid-19 morbidity decreases with Tixagevimab/cilgavimab preexposure prophylaxis in kidney transplant recipients non/low vaccine responders

Humoral SARS-CoV-2 vaccine responses are durable in solid organ transplant recipients with and without HIV

Background

Solid organ transplant (SOT) recipients may have a suboptimal humoral immune response to the coronavirus disease 2019 (COVID-19) vaccine, prompting the need for additional doses of vaccine for immunocompromised patients. However, data regarding immune responses to vaccination specifically in SOT recipients with well controlled HIV are lacking.

Methods

We conducted a prospective observational cohort single-center study of SOT recipients with and without HIV-1 who had received two doses of mRNA COVID-19 vaccine and were planning to receive additional doses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binding and neutralizing antibody responses were measured at several time points after vaccination.

Findings

Of the 122 SOT recipients enrolled, 44 (36%) were people with HIV (PWH). Overall, 65% (50/77) of all SOT recipients were seropositive prior to a third vaccine dose. Seropositive SOT recipients with HIV had comparable anti-spike antibody responses at baseline and over time to those without HIV. In addition, HIV status did not impact neutralizing titers in our SOT cohort. Twenty-seven participants were seronegative at baseline; three (11%) were participants with HIV. In addition, 78% (21/27) of participants seroconverted over the duration of the study; of those who remained seronegative, none had HIV, but all were on an antimetabolites.

Interpretation

HIV status did not impact longitudinal spike-binding antibody titers or neutralizing titers in SOT recipients.

Research in context

Evidence before this study

Solid organ transplant (SOT) recipients may mount poor humoral immune responses to COVID-19 vaccines, prompting the need for additional vaccine doses in this patient population. Additional risk factors for poor immune response in this population have been described and include for example, age or use of certain immunosuppressant therapies. However, humoral responses to COVID-19 vaccine in SOT recipients with HIV have not previously been described.

Added value of this study

We conducted a prospective observational single center study of solid organ transplant recipients with and without HIV and measured SARS-CoV-2 binding and neutralizing antibody responses longitudinally. Our study results demonstrate that HIV status did not appear to be an additional risk factor that affected the durability of spike-antibody titers or neutralizing titers in SOT recipients over time.

Implications of all the available evidence

Well-controlled HIV infection is not an additional risk factor in SOT recipients when assessing responses to COVID-19 vaccine. Future studies should continue to focus on other risk factors, such as type of immunosuppressant therapies and timing of vaccination in relationship to transplant.

SARS-COV-2 Pre-Exposure Prophylaxis With Tixagevimab-Cilgavimab in Haematological, Immunocompromised Patients in the Omicron Era

BACKGROUND

Pre-exposure prophylaxis with tixagevimab-cilgavimab significantly reduced severe COVID-19 outcomes in high-risk individuals during the pre-Omicron era (PROVENT trial). However, efficacy in patients with haematological malignancies (HM) was underreported. The rapid emergence of Omicron strains in 2021 showed reduced neutralizing activity in preclinical data, but real-world data remains limited due to short follow-up.

PATIENTS AND METHODS

We aimed to evaluate the effectiveness and safety of tixagevimab-cilgavimab in 86 HM patients during the early Omicron wave, including the BA.2, BA.5, and XBB.1 sublineages. These patients received PrEP between February and August 2022 due to impaired vaccine response (72%) and B-cell depletion (46.5%). They were followed prospectively until April 2023, with a median follow-up of 297 days.

RESULTS

Breakthrough SARS-CoV-2 infections occurred in 32.6% of patients, with 22.1% within six months. Infections within six months were milder and shorter. B-cell depletion within six (p = 0.035) and twelve months (p = 0.016) was identified as risk factor for breakthrough infections. No new safety events were reported.

CONCLUSION

Our data showed that tixagevimab-cilgavimab prophylaxis effectively reduces severe COVID-19 outcomes in patients with HM, particularly within the first six months, even during the Omicron era. However, those with recent B-cell depletion (within 12 months) remained at high risk.

Therapeutic Potential of Neutralizing Monoclonal Antibodies (nMAbs) against SARS-CoV-2 Omicron Variant

BACKGROUND

The COVID-19 pandemic has spurred significant endeavors to devise treatments to combat SARS-CoV-2. A limited array of small-molecule antiviral drugs, specifically monoclonal antibodies and interferon therapy, have been sanctioned to treat COVID-19. These treatments typically necessitate administration within ten days of symptom onset. There have been reported reductions in the effectiveness of these medications due to mutations in non-structural protein genes, particularly against Omicron subvariants. This underscores the pressing requirement for healthcare systems to continually monitor pathogen variability and its impact on the efficacy of prevention and treatments.

AIM

This review aimed to comprehend the therapeutic benefits and recent progress of nMAbs for preventing and treating the Omicron variant of SARS-CoV-2.

RESULTS AND DISCUSSION

Neutralizing monoclonal antibodies (nMAbs) provide a treatment avenue for severely affected individuals, especially those at high risk for whom vaccination is not viable. With their specific epitope affinity, they pose no significant risk of severe adverse effects. The degree of reduction in neutralization varies significantly across different monoclonal antibodies and variant combinations. For instance, Sotrovimab maintained its neutralization effectiveness against Omicron BA.1, but exhibited diminished efficacy against BA.2, BA.4, BA.5, and BA.2.12.1.

CONCLUSION

Bebtelovimab has been observed to preserve its efficacy against all subtypes of the Omicron variant. Subsequently, WKS13, mAb-39, 19n01, F61-d2 cocktail, etc., have become effective. This review has highlighted the therapeutic implications of nMAbs in SARS-CoV-2 Omicron treatment and the progress of COVID-19 drug discovery.

Tixagevimab-cilgavimab for preventing breakthrough COVID-19 in dialysis patients: a prospective study

Background

The effectiveness of tixagevimab-cilgavimab as pre-exposure prophylaxis (PrEP) against breakthrough coronavirus disease 2019 (COVID-19) in dialysis patients remains uncertain due to limited data.

Methods

In this multicenter prospective study, we enrolled vaccinated dialysis patients and divided them into two groups: a tixagevimab-cilgavimab group (received a 150 mg/150 mg intramuscular dose of tixagevimab-cilgavimab) and a control group (age-matched patients not receiving tixagevimab-cilgavimab). The primary outcome was the breakthrough COVID-19 rate at 6 months, whereas secondary outcomes included COVID-19-related hospitalization, intensive care unit admission, endotracheal intubation and mortality. The safety of tixagevimab-cilgavimab was assessed.

Results

Two hundred participants were enrolled, with equal numbers in each group (n = 100 each). Baseline characteristics were comparable between groups, except for a higher number of COVID-19 vaccine doses in the tixagevimab-cilgavimab group [median (IQR) 4 (3-5) vs. 3 (3-4); P = .01]. At 6 months, the breakthrough COVID-19 rates were comparable between the tixagevimab-cilgavimab (17%) and control (15%) groups (P = .66). However, the median (IQR) time to diagnosis of breakthrough infections tended to be longer in the tixagevimab-cilgavimab group [4.49 (2.81-4.98) vs 1.96 (1.65-2.91) months; P = .08]. Tixagevimab-cilgavimab significantly reduced COVID-19-related hospitalization rates (5.9% vs 40.0%; P = .02) among participants with breakthrough infections. All tixagevimab-cilgavimab-related adverse events were mild.

Conclusion

The use of tixagevimab-cilgavimab as PrEP in vaccinated dialysis patients during the Omicron surge did not prevent breakthrough infections but significantly reduced COVID-19-related hospitalizations. Further research should prioritize alternative strategies.

Risk of SARS-CoV-2 infection and severe COVID-19 in hematological patients who received or not pre-exposure prophylaxis with tixagevimab/cilgavimab: a target trial emulation

We emulated a hypothetical target trial in which hematological subjects cared at the University Hospital of Pisa (Italy) received or not SARS-CoV-2 prophylaxis with tixagevimab/cilgavimab. Subjects who received prophylaxis (cases) were compared to those who did not (controls). The main outcome was SARS-CoV-2 infection in the subsequent 6 months. Inverse probability weighting (IPW) was used to adjust for confounders. A multivariable analysis was performed to identify variables associated with SARS-CoV-2 infection. We recruited 462 patients: 228 received prophylaxis, 234 were controls. COVID-19 was lower in cases compared to controls (16.7% vs 24.8%, p = 0.03, after IPW 14.3% vs 24.6%, p = 0.01). On multivariable analysis, B-cell depleting therapies (HR 2.09, 95%CI 1.05-4.18, p = 0.037) were associated with increased risk of COVID-19, while tixagevimab/cilgavimab prophylaxis (HR 0.45, 95%CI 0.27-0.73, p = 0.001) and previous SARS-CoV-2 infection (HR 0.27, 95%CI 0.14-0.51, p < 0.001) were protective. In conclusion, prophylaxis with monoclonal antibodies may reduce the risk of COVID-19 in hematological patients.

Longitudinal outcomes of COVID-19 in solid organ transplant recipients from 2020 to 2023

Data regarding coronavirus disease 2019 (COVID-19) outcomes in solid organ transplant recipients (SOTr) across severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) waves, including the impact of different measures, are lacking. This cohort study, conducted from March 2020 to May 2023 in Toronto, Canada, aimed to analyze COVID-19 outcomes in 1975 SOTr across various SARS-CoV-2 waves and assess the impact of preventive and treatment measures. The primary outcome was severe COVID-19, defined as requiring supplemental oxygen, with secondary outcomes including hospitalization, length of stay, intensive care unit (ICU) admission, and 30-day and 1-year all-cause mortality. SARS-CoV-2 waves were categorized as Wildtype/Alpha/Delta (318 cases, 16.1%), Omicron BA.1 (268, 26.2%), Omicron BA.2 (268, 13.6%), Omicron BA.5 (561, 28.4%), Omicron BQ.1.1 (188, 9.5%), and Omicron XBB.1.5 (123, 6.2%). Severe COVID-19 rate was highest during the Wildtype/Alpha/Delta wave (44.6%), and lower in Omicron waves (5.7%-16.1%). Lung transplantation was associated with severe COVID-19 (OR: 4.62, 95% CI: 2.71-7.89), along with rituximab treatment (OR: 4.24, 95% CI: 1.04-17.3), long-term corticosteroid use (OR: 3.11, 95% CI: 1.46-6.62), older age (OR: 1.51, 95% CI: 1.30-1.76), chronic lung disease (OR: 2.11, 95% CI: 1.36-3.30), chronic kidney disease (OR: 2.18, 95% CI: 1.17-4.07), and diabetes (OR: 1.97, 95% CI: 1.37-2.83). Early treatment and ≥3 vaccine doses were associated with reduced severity (OR: 0.29, 95% CI: 0.19-0.46, and 0.35, 95% CI: 0.21-0.60, respectively). Tixagevimab/cilgavimab and bivalent boosters did not show a significant impact. The study concludes that COVID-19 severity decreased across different variants in SOTr. Lung transplantation was associated with worse outcomes and may benefit more from preventive and early therapeutic interventions.

Safety and efficacy of tixagevimab/cilgavimab for pre-exposure prophylaxis in kidney transplant recipients: a multicenter retrospective cohort study

BACKGROUND

Immunocompromised patients show an impaired vaccine response and remain at high risk of severe COVID-19, despite vaccination. Neutralizing monoclonal antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed for prophylaxis and treatment. The combination tixagevimab/cilgavimab (AZD7442) has been authorized for emergency use as pre-exposure prophylaxis for COVID-19, but data on safety and efficacy in kidney transplant recipients during the Omicron period are limited.

METHODS

We conducted a multicenter retrospective cohort study including 253 kidney transplant recipients, of whom 98 were treated with tixagevimab/cilgavimab 150 mg/150 mg and 155 who received only four doses of the BNT162b2 mRNA vaccine.

RESULTS

Only 13.3% of patients developed SARS-CoV-2 infection after the administration of tixagevimab/cilgavimab; in comparison, 34.2% of patients had been infected after the fourth dose of vaccine (p = 0.00013). Most infected patients in the AZD7442 group remained asymptomatic (92.3% vs 54.7%), 7.7% had mild symptoms and none had severe disease, need for hospitalization or died, while in the control group, 9.4% of patients had moderate or severe disease (p = 0.04). Using Kaplan-Meier curves we demonstrated that the controls presented early infection compared to the AZD7442 group (p = 0.000014). No changes in eGFR or proteinuria, assessed before and after the administration, were observed.

CONCLUSIONS

In conclusion, our study showed that tixagevimab/cilgavimab 150/150 mg is effective and safe in preventing infection and severe disease when administered to patients with weak or no response to COVID-19 vaccine.

Tixagevimab/cilgavimab prophylaxis against COVID-19 in solid organ transplant recipients: a systematic review and meta-analysis

Background

Tixagevimab/cilgavimab (Tix/Cil) shows promise as a prophylactic treatment against coronavirus disease 2019 (COVID-19) in solid organ transplant recipients (SOTRs). This study was performed to assess the effectiveness of Tix/Cil for preexposure prophylaxis against COVID-19 in this population.

Methods

We systematically searched the Cochrane Library, Web of Science, PubMed, and Embase databases to identify articles relevant to our study up to December 15, 2023. Comprehensive Meta-Analysis (ver. 3.0) was used for data analysis.

Results

The meta-analysis included seven eligible retrospective studies, encompassing a total of 4,026 SOTRs. The analysis revealed significant differences in SOTRs who received Tix/Cil preexposure prophylaxis relative to those who did not. Specifically, these differences were observed in the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.15-0.60), hospitalization (OR, 0.24; 95% CI, 0.08-0.70), and intensive care unit admission (OR, 0.07; 95% CI, 0.02-0.22). However, mortality rate did not differ significantly between the two groups (P=0.06).

Conclusions

The evidence supporting the effectiveness of Tix/Cil as preexposure prophylaxis against SARS-CoV-2 in SOTRs is of a low to moderate level. Further high-quality research is necessary to understand its effects on this population.

Neutralizing antibody responses and cellular responses against SARS-CoV-2 Omicron subvariants after mRNA SARS-CoV-2 vaccination in kidney transplant recipients

Although the mRNA SARS-CoV-2 vaccine has improved the mortality rate in the general population, its efficacy against rapidly mutating virus strains, especially in kidney transplant recipients, remains unclear. We examined the anti-SARS-CoV-2 spike protein IgG antibody and neutralizing antibody titers and cellular immunity against B.1.1, BA.1, and BA.5 antigens in 73 uninfected kidney recipients and 16 uninfected healthy controls who received three doses of an mRNA SARS-CoV-2 vaccine. The IgG antibody titers were significantly lower in recipients than in healthy controls. Similarly, neutralizing antibody titers against three viral variants were significantly lower in recipients. When the virus was mutated, the neutralizing antibody titers decreased significantly in both groups. In cellular immunity analysis, the number of spike-specific CD8 + non-naïve T cells against three variants significantly decreased in recipients. Conversely, the frequency of spike-specific Th2 CD4 + T-cells in recipients was higher than that in healthy controls. Nineteen recipients and six healthy controls also received a bivalent omicron-containing booster vaccine, leading to increase IgG and neutralizing antibody titers in both groups. After that, eleven recipients and five healthy controls received XBB.1.5 monovalent vaccines, increasing the neutralizing antibody titers against not only XBB.1.5, but also EG.5.1 and BA.2.86 antigens in kidney recipients. Although kidney recipients did not gain sufficient immunity against Omicron BA.5 with the third dose of vaccine, humoral response against mutant SARS-CoV-2 lineages significantly increased after bivalent Omicron-containing booster vaccine and the XBB.1.5 monovalent vaccine. Therefore, it is important for kidney recipients to continue to administer updated vaccines.

Evaluation of T Cell Response to SARS-CoV-2 in Kidney Transplant Recipients Receiving Monoclonal Antibody Prophylaxis and the Utility of a Bivalent mRNA Vaccine Booster Dose

Monoclonal antibodies have been administered to kidney transplant recipients (KTRs) with a poor or non-responder status to SARS-CoV-2 vaccination. The cellular response to SARS-CoV-2 has been poorly studied in this context. We assessed the T cell response to SARS-CoV-2 in 97 patients on the day of the injection of tixagevimab/cilgavimab using an IFNγ enzyme-linked immunospot assay (ELISPOT). Among the 97 patients, 34 (35%) developed COVID-19 before the injection. Twenty-nine (85.3%) had an ELISPOT compatible with a SARS-CoV-2 infection. There was no difference between KTRs under belatacept or tacrolimus treatment. Sixty-three patients (64.9%) had no known COVID-19 prior to the ELISPOT, but nine (14.3%) had a positive ELISPOT. In 21 KTRs with a positive ELISPOT who received a booster dose of a bivalent mRNA vaccine, median antibody titers and spike-reactive T cells increased significantly in patients under tacrolimus but not belatacept. Our study emphasizes the potential usefulness of the exploration of immune cellular response to SARS-CoV-2 by ELISPOT. In KTRs with a positive ELISPOT and under CNI therapy, a booster dose of mRNA vaccine seems effective in inducing an immune response to SARS-CoV-2.

Anti SARS-CoV-2 Monoclonal Antibodies in Pre-Exposure or Post-Exposure in No- or Weak Responder to Vaccine Kidney Transplant Recipients: Is One Strategy Better than Another?

Background: Kidney transplant recipients (KTRs) are likely to develop severe COVID-19 and are less well-protected by vaccines than immunocompetent subjects. Thus, the use of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) to confer a passive immunity appears attractive in KTRs. Methods: This retrospective monocentric cohort study was conducted between 1 January 2022 and 30 September 2022. All KTRs with a weak antibody response one month after three doses of mRNA vaccine (anti spike IgG < 264 (BAU/mL)) have received tixagevimab-cilgavimab in pre-exposure (group 1), post-exposure (group 2) or no specific treatment (group 3). We compared COVID-19 symptomatic hospitalizations, including intensive care unit hospitalizations, oxygen therapy, and death, between the three groups. Results: A total of 418 KTRs had SARS-CoV-2 infection in 2022. During the study period, we included 112 KTRs in group 1, 40 KTRs in group 2, and 27 KTRs in group 3. The occurrence of intensive care unit hospitalization, oxygen therapy, and COVID-19 death was significantly increased in group 3 compared to group 1 or 2. In group 3, 5 KTRs (18.5%) were admitted to the intensive care unit, 7 KTRs (25.9%) needed oxygen therapy, and 3 KTRs (11.1%) died. Patients who received tixagevimab-cilgavimab pre- or post-exposure had similar outcomes. Conclusions: This retrospective real-life study supports the relative effectiveness of tixagevimab-cilgavimab on COVID-19 infection caused by Omicron, used as a pre- or post-exposure therapy. The continued evolution of Omicron variants has made tixagevimab-cilgavimab ineffective and reinforces the need for new therapeutic monoclonal antibodies for COVID-19 active on new variants.

Breakthrough SARS-CoV-2 infections among recipients of tixagevimab-cilgavimab prophylaxis: A citywide real-world effectiveness study

There are limited real-world data on the effectiveness of tixagevimab-cilgavimab as pre-exposure prophylaxis of COVID-19. We describe lessons learned when coordinating data collection and identifying breakthrough SARS-CoV-2 infections among patients across indications and institutions in a major US city. The Chicago Department of Public Health requested patient-level tixagevimab-cilgavimab administration data from all prescribing providers in Chicago, for treatments December 8, 2021 through June 30, 2022. Records were matched to COVID-19 vaccinations and laboratory-confirmed SARS-CoV-2 infections through December 31, 2022. Due to difficulty collecting data from all providers, targeted follow-up was conducted to improve completeness on key variables (demographics, vaccination status, clinical indication for prophylaxis). Over half of reported tixagevimab-cilgavimab administrations were to patients residing outside Chicago. Five hundred forty-four Chicago residents who received at least one dose of tixagevimab-cilgavimab were included in this analysis. Most were age 50 years or older (72%), Black non-Latinx (33%) or White non-Latinx (29%), and fully vaccinated (80%). Seventy-five patients (14%) had laboratory-confirmed COVID-19. Patients with and without breakthrough infections were demographically similar. Clinical indication was missing for >95% of cases, improved to 64% after follow-up; the most frequently specified was hematologic malignancy (10%). Severe outcomes were uncommon: 16% had documented COVID-19-related hospitalizations, one death was identified. Tixagevimab-cilgavimab recipients in Chicago had a lower rate of severe SARS-CoV-2 infection than reported among other untreated high-risk patients, including during predominance of non-neutralizing variants. Improving stakeholder collaboration is essential for generation of real-world effectiveness data, informing pandemic preparedness and optimizing use of medical countermeasures.

The efficacy of tixagevimab/cilgavimab (Evusheld) in prophylaxis and treatment of COVID-19 in immunocompromised patients: a systematic review and meta-analysis

BACKGROUND

During the COVID-19 pandemic, some populations, including immunocompromised patients, could not tolerate COVID-19 vaccination or had low responses. Evusheld is a combined neutralizing monoclonal antibody containing tixagevimab and cilgavimab. The World Health Organization (WHO) has approved this combination as pre-exposure prophylaxis (PrEP) and treatment for immunocompromised patients. With the new variant, the (WHO) recommended an increase in dose from 300 to 600 mg with a booster dose after 6 months. The target of this review was to compare the efficacy of the two doses, 300 mg and 600 mg of tixagevimab/cilgavimab (Evusheld) as prophylaxis for higher-risk individuals to reveal if there is a significant difference in efficacy between those two doses of the drug.

METHODS

In this study, electronic databases (PubMed, Web of Science core collection, Scopus, and Cochran) were investigated for articles up to 31/12/2022 in English using a well-established search strategy. We included studies conducted in immunocompromised patients (aged ≥ 12 years) (WHO) received Evusheld as prophylaxis or treatment for COVID-19. After excluding studies inconsistent with the selection criteria, 24 were involved, 22 of which were included in the meta-analysis. We analyzed the data by using RevMan 5.4 program software.

RESULTS

In the double-arm subgroup analysis, Evusheld 600 mg, administered as prophylaxis, showed no significant difference in the COVID-19 infection rate, mortality rate, or needed hospitalization rate compared with the dose of 300 mg (p = 0.13, p = 0.29, and p = 0.25, respectively). In the single-arm subgroup analysis, Evusheld 600 mg, administered as prophylaxis, showed a significant decrease in the COVID-19 infection rate and the hospitalization rate compared with the dose of 300 mg (p = 0.0001, p = 0.007, respectively). As a treatment, Evusheld showed a significant decrease in the mortality rate over the placebo group (p = 0.01) in COVID-19 patients.

CONCLUSION

This result indicated that Evusheld was an effective prophylactic and therapeutic drug for COVID-19 infection, especially for immunocompromised patients, but there was no considerable variation between the high and low doses. Further prospective and randomized controlled trials (RCTs) with increased population sizes are necessary to show the valuable benefit of the high dose of Evusheld in COVID-19 prevention and treatment and to compare the difference between the two doses within adverse events.

Measures to Increase Immunogenicity of SARS-CoV-2 Vaccines in Solid Organ Transplant Recipients: A Narrative Review

Purpose of review: To review the data on the immunogenicity of COVID-19 vaccines, administered by different strategies, in solid organ transplant recipients (SOTRs). Recent findings: COVID-19 booster vaccines were given to SOTRs as a widespread practice in many transplant centers, mostly as the third and/or fourth dose in an extended vaccine series, with a significantly improved humoral response compared with the initial two-dose scheme. However, one-third of SOTRs remained unresponsive, despite these boosters. Next steps: Vaccination with standard dosing remains the most feasible strategy for attaining protection against COVID-19. Additional booster doses and temporarily holding or reducing mycophenolate mofetil/mycophenolic acid may provide immunogenicity to vaccines, according to recent studies demonstrating some efficacy with these measures. Preexposure prophylaxis with monoclonal antibodies showed benefit in immunocompromised patients but is no longer recommended by the National Institutes of Health (NIH) due to diminished efficacy against Omicron and recent variants. Screening for the presence and titers of SARS-CoV-2-specific antibodies in SOTRs is not recommended in most clinical settings. T cell-based techniques are needed to evaluate vaccine efficacy and risk of infection. As SARS-CoV-2 continues to evolve, new vaccines based on conservative protein component/complexes of the COVID virus, in addition to its spike protein, are warranted to offer prolonged protection.

Lessons from SENCOVAC: A prospective study evaluating the response to SARS-CoV-2 vaccination in the CKD spectrum

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has negatively impacted on patients of the whole CKD spectrum, causing high rates of morbi-mortality. SARS-CoV-2 vaccines opened a new era, but patients with CKD (including kidney transplant, hemodialysis and peritoneal dialysis) were systematically excluded from pivotal clinical trials. The Spanish Society of Nephrology promoted the multicentric national SENCOVAC study aimed at assessing immunological responses after vaccination in patients with CKD. During the first year after vaccination, patients with non-dialysis CKD and those on hemodialysis and peritoneal dialysis presented good anti-Spike antibody responses to vaccination, especially after receiving the third and fourth doses. However, kidney transplant recipients presented suboptimal responses after any vaccination schedule (initial, third and fourth dose). Especially worrisome is the situation of a patients with a persistently negative humoral response that do not seroconvert after boosters. In this regard, monoclonal antibodies targeting SARS-CoV-2 have been approved for high-risk patients, although they may become obsolete as the viral genome evolves. The present report reviews the current status of SARS-CoV-2 vaccination in the CKD spectrum with emphasis on lessons learned from the SENCOVAC study. Predictors of humoral response, including vaccination schedules and types of vaccines, as well as the integration of vaccines, monoclonal antibodies and antiviral agents are discussed.

Efficacy of pre-exposure prophylaxis to prevent SARS-CoV-2 infection after lung transplantation: a two center cohort study during the omicron era

PURPOSE

Lung transplant (LTx) recipients are at risk for poor outcomes from coronavirus disease 2019 (COVID-19). The aim of the study was to assess the outcome of patients receiving pre-exposure prophylaxis (PrEP) with tixagevimab and cilgavimab after LTx.

METHODS

All LTx recipients with outpatient visits from February 28th to October 31st, 2022 at two German centers were included. Baseline characteristics were recorded and patients followed until November 30rd, 2022. Infections with SARS-CoV-2, disease severity, and COVID-19-associated death were compared between patients with and without PrEP.

RESULTS

In total, 1438 patients were included in the analysis, and 419 (29%) received PrEP. Patients receiving PrEP were older and earlier after transplantation, had lower glomerular filtration rates, and lower levels of SARS-CoV-2-S antibodies. In total, 535 patients (37%) developed SARS-CoV-2 infection during a follow-up of median of 209 days. Fewer infections occurred in patients with PrEP during the study period (31% vs. 40%, p = 0.004). Breakthrough SARS-CoV-2 infections after PrEP occurred in 77 patients (19%). In total, 37 infections (8%) were severe or critical. No difference in severity of COVID-19 was observed between patients with and without PrEP. There were 15 COVID-19-associated deaths (n = 1 after PrEP). Compared to matched controls, there was a non-significant difference towards a lower risk for moderate to critical COVID-19 (p 0.184).

CONCLUSION

The number of SARS-CoV-2 infections was lower in LTx recipients with PrEP. Despite being at higher risk for worse outcome severity of COVID-19 and associated mortality were similar in patients with and without PrEP.

Outcomes of targeted treatment in immunocompromised patients with asymptomatic or mild COVID-19: a retrospective study

The aim of this study was to describe the outcomes of targeted COVID-19 treatments in immunocompromised patients with asymptomatic or mild COVID-19 during the period of expansion of the different Omicron subvariants in France. A retrospective monocentric observational study was performed. All immunocompromised patients aged 18 or more, with asymptomatic SARS-CoV-2 infection or mild COVID-19, and who had received a targeted treatment with sotrovimab, tixagevimab/cilgavimab, nirmatrelvir/ritonavir or remdesivir at the Bordeaux University Hospital from 1st January 2022 to 31st December 2022 were eligible. The primary outcomes of interest was defined as a composite of either (i) progression to moderate (WHO-Clinical Progression Scale at 4 or 5) or severe COVID-19 (WHO-CPS ≥ 6), or (ii) the occurrence of COVID-19-related death. The secondary outcomes of interest were the components of the primary outcome. Outcomes were collected until day 30 after targeted treatment administration or at discharge for patients still hospitalised in relation with COVID-19 at day 30. 223 immunocompromised patients received targeted treatment for asymptomatic SARS-CoV-2 infection or mild COVID-19: 114 received sotrovimab, 50 tixagevimab/cilgavimab, 49 nirmatrelvir/ritonavir, and 10 remdesivir. Among 223 treated patients, 10 (4.5%) progressed to moderate or severe disease: three patients (1.3%) progressed to moderate COVID-19 and 7 (3.1%) patients progressed to severe disease. Among them, 4 (1.8%) died of COVID-19. More than 95% of immunocompromised patients with asymptomatic SARS-CoV-2 infection or mild COVID-19 treated by targeted therapies during the Omicron subvariants era did not progress to moderate or severe disease.

Monoclonal antibodies as COVID-19 prophylaxis therapy in immunocompromised patient populations

OBJECTIVES

The objective of this review was to examine the latest literature regarding the effectiveness of monoclonal antibodies as COVID-19 prophylaxis therapy for immunocompromised patient populations.

METHODS

Literature review of published real-world and randomized control trials (RCTs) from 2020 to May 2023.

RESULTS

COVID-19 is highly transmissible with potentially serious health outcomes, underscoring the need for effective prevention and treatment strategies. Vaccines are highly effective at preventing COVID-19 for the general population; however, efficacy is often impaired in immunocompromised patients given insufficient response to initial exposure and/or memory for secondary exposures. Some individuals may also have contraindications to vaccination. As such, additional protective measures are needed to bolster the immune response in these populations. Monoclonal antibodies have been effective at bolstering immune system responses to COVID-19 among immunocompromised patients; however, they are proving ineffective against the most recent Omicron strains (BA.4 and BA.5).

CONCLUSION

Several studies have investigated the efficacy of monoclonal antibodies as pre- and post-prophylaxis for COVID-19. Historical evidence is promising; however, new variants of concern are proving challenging for currently available regimens.

Health Outcomes and Cost-effectiveness of Monoclonal SARS-CoV-2 Antibodies as Pre-exposure Prophylaxis

Importance

Pre-exposure prophylaxis with neutralizing SARS-CoV-2 monoclonal antibodies (mAbs PrEP) prevents infection and reduces hospitalizations and the duration thereof for COVID-19 and death among high-risk individuals. However, reduced effectiveness due to a changing SARS-CoV-2 viral landscape and high drug prices remain substantial implementation barriers.

Objective

To assess the cost-effectiveness of mAbs PrEP as COVID-19 PrEP.

Design, Setting, and Participants

For this economic evaluation, a decision analytic model was developed and parameterized with health care outcome and utilization data from individuals with high risk for COVID-19. The SARS-CoV-2 infection probability, mAbs PrEP effectiveness, and drug pricing were varied. All costs were collected from a third-party payer perspective. Data were analyzed from September 2021 to December 2022.

Main Outcomes and Measures

Health care outcomes including new SARS-CoV-2 infections, hospitalization, and deaths. The cost per death averted and cost-effectiveness ratios using a threshold for prevention interventions of $22 000 or less per quality-adjusted life year (QALY) gained.

Results

The clinical cohort consisted of 636 individuals with COVID-19 (mean [SD] age 63 [18] years; 341 [54%] male). Most individuals were at high risk for severe COVID-19, including 137 (21%) with a body mass index of 30 or higher, 60 (9.4%) with hematological malignant neoplasm, 108 (17%) post-transplantation, and 152 (23.9%) who used immunosuppressive medication before COVID-19. Within the context of a high (18%) SARS-CoV-2 infection probability and low (25%) effectiveness the model calculated a short-term reduction of 42% ward admissions, 31% intensive care unit (ICU) admissions, and 34% deaths. Cost-saving scenarios were obtained with drug prices of $275 and 75% or higher effectiveness. With a 100% effectiveness mAbs PrEP can reduce ward admissions by 70%, ICU admissions by 97%, and deaths by 92%. Drug prices, however, need to reduce to $550 for cost-effectiveness ratios less than $22 000 per QALY gained per death averted and to $2200 for ratios between $22 000 and $88 000.

Conclusions and Relevance

In this study, use of mAbs PrEP for preventing SARS-CoV-2 infections was cost-saving at the beginning of an epidemic wave (high infection probability) with 75% or higher effectiveness and drug price of $275. These results are timely and relevant for decision-makers involved in mAbs PrEP implementation. When newer mAbs PrEP combinations become available, guidance on implementation should be formulated ensuring a fast rollout. Nevertheless, advocacy for mAbs PrEP use and critical discussion on drug prices are necessary to ensuring cost-effectiveness for different epidemic settings.

Tixagevimab/Cilgavimab as pre-exposure prophylaxis against SARS-CoV-2 in patients with hematological malignancies

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.

Cellular and humoral immune responses after a third dose of SARS-CoV-2 mRNA vaccine in lung transplant recipients in Japan

BACKGROUND

Lung transplant (LTx) recipients are at higher risk of infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). There is an increasing demand for additional analysis regarding the efficacy and safety of after the initial series of mRNA SARS-CoV-2 vaccines in Japanese transplant recipients.

METHOD

In this open-label, nonrandomized prospective study carried out at Tohoku University Hospital, Sendai, Japan, LTx recipients and controls received third doses of either the BNT162b2 or the mRNA-1273 vaccine, and the cellular and humoral immune responses were analyzed.

RESULTS

A cohort of 39 LTx recipients and 38 controls participated in the study. The third dose of SARS-CoV-2 vaccine promoted much greater humoral responses at 53.9 % of LTx recipients than after the initial series at 28.2 % of patients without increasing the risk of adverse events. However, still fewer LTx recipients responded to the SARS-CoV-2 spike protein with the median IgG titer of 129.8 AU/mL and with the median IFN-γ level of 0.01 IU/mL when compared to controls with those of 7394 AU/mL and 0.70 IU/mL, respectively.

CONCLUSION

Although the third dose of mRNA vaccine in LTx recipients was effective and safe, impaired cellular and humoral responses to SARS-CoV-2 spike protein were noted. Given lower antibody production and establishing vaccine safety, repeating the administration of mRNA vaccine will lead to robust protection in such a high-risk population (jRCT1021210009).

Real-world experience of tixagevimab-cilgavimab pre-exposure prophylaxis in orthotopic heart transplant recipients

BACKGROUND

Pre-exposure prophylaxis with tixagevimab-cilgavimab (tix-cil) may be associated with cardiovascular adverse events. Also, in vitro studies have reported a reduced activity of tix-cil against emerging SARS-CoV-2 Omicron subvariants. Our study aimed to report the real-world outcomes of tix-cil prophylaxis in orthotopic heart transplant (OHT) recipients METHODS: We retrospectively studied all OHT recipients who received one dose of tix-cil (150-150 mg or 300-300 mg) at Mayo Clinic in Arizona, Florida, and Minnesota, between February 5, 2022 and September 8, 2022. We collected data on cardiovascular adverse events and breakthrough COVID-19 following tix-cil administration.

RESULTS

One hundred sixty-three OHT recipients were included. The majority were male (65.6%), and the median age was 61 years (IQR 48, 69). During the median follow-up of 164 days (IQR 123, 190), one patient presented an episode of asymptomatic hypertensive urgency that was managed with outpatient antihypertensive treatment optimization. Twenty-four patients (14.7%) experienced breakthrough COVID-19 at the median of 63.5 days (IQR 28.3, 101.3) after tix-cil administration. The majority (70.8%) completed the primary vaccine series and received at least one booster dose (70.8%). Only one patient with breakthrough COVID-19 required hospitalization. All patients survived.

CONCLUSIONS

In this cohort of OHT recipients, no patients developed severe cardiovascular events related to tix-cil. The high incidence of breakthrough COVID-19 could be due to the reduced activity of tix-cil against current circulating SARS-CoV-2 Omicron variants. These results emphasize the need for a multimodal prevention strategy against SARS-CoV-2 in these high-risk patients.

Barac Y, Shlomai A, Bar-Haim E, Shtraichman O. Immunogenicity of a Third Dose of BNT162b2 Vaccine among Lung Transplant Recipients—A Prospective Cohort Study

Two doses of mRNA SARS-CoV-2 vaccines elicit an attenuated humoral immune response among immunocompromised patients. Our study aimed to assess the immunogenicity of a third dose of the BNT162b2 vaccine among lung transplant recipients (LTRs). We prospectively evaluated the humoral response by measuring anti-spike SARS-CoV-2 and neutralizing antibodies in 139 vaccinated LTRs ~4–6 weeks following the third vaccine dose. The t-cell response was evaluated by IFNγ assay. The primary outcome was the seropositivity rate following the third vaccine dose. Secondary outcomes included: positive neutralizing antibody and cellular immune response rate, adverse events, and COVID-19 infections. Results were compared to a control group of 41 healthcare workers. Among LTRs, 42.4% had a seropositive antibody titer, and 17.2% had a positive t-cell response. Seropositivity was associated with younger age (t = 3.736, p < 0.001), higher GFR (t = 2.355, p = 0.011), and longer duration from transplantation (t = −1.992, p = 0.024). Antibody titer positively correlated with neutralizing antibodies (r = 0.955, p < 0.001). The current study may suggest the enhancement of immunogenicity by using booster doses. Since monoclonal antibodies have limited effectiveness against prevalent sub-variants and LTRs are prone to severe COVID-19 morbidity, vaccination remains crucial for this vulnerable population.

Efficacy and safety of tixagevimab-cilgavimab as pre-exposure prophylaxis for COVID-19: A systematic review and meta-analysis

Some proportions of populations, such as immunocompromised patients and organ transplant recipients might have inadequate immune responses to the vaccine for coronavirus disease 2019 (COVID-19). For these groups of populations, administering monoclonal antibodies might offer some additional protection. This review sought to analyze the effectiveness and safety of tixagevimab-cilgavimab (Evusheld) as pre-exposure prophylaxis against COVID-19. We used specific keywords to comprehensively search for potential studies on PubMed, Scopus, Europe PMC, and ClinicalTrials.gov sources until 3 September 2022. We collected all published articles that analyzed tixagevimab-cilgavimab on the course of COVID-19. Review Manager 5.4 was utilized for statistical analysis. Six studies were included. Our pooled analysis revealed that tixagevimab-cilgavimab prophylaxis may decrease the rate of SARS-CoV-2 infection (OR: 0.24; 95% CI: 0.15-0.40, p < 0.00001, I2  = 75%), lower COVID-19 hospitalization rate (OR: 0.13; 95% CI: 0.07-0.24, p < 0.00001, I2  = 0%), decrease the severity risk (OR: 0.13; 95% CI: 0.07-0.24, p < 0.00001, I2  = 0%), and lower COVID-19 deaths (OR: 0.17; 95% CI: 0.03-0.99, p = 0.05, I2  = 72%). In the included studies, no major adverse events were reported. This study proposes that tixagevimab-cilgavimab was effective and safe for preventing COVID-19. Tixagevimab-cilgavimab may be offered to those who cannot be vaccinated or have inadequate immune response from the COVID-19 vaccine to give additional protection.

Neutralizing activity and 3-month durability of tixagevimab and cilgavimab prophylaxis against Omicron sublineages in transplant recipients

Neutralizing antibody (nAb) responses are attenuated in solid organ transplant recipients (SOTRs) despite severe acute respiratory syndrome-coronavirus-2 vaccination. Preexposure prophylaxis (PrEP) with the antibody combination tixagevimab and cilgavimab (T+C) might augment immunoprotection, yet in vitro activity and durability against Omicron sublineages BA.4/5 in fully vaccinated SOTRs have not been delineated. Vaccinated SOTRs, who received 300 + 300 mg T+C (ie, full dose), within a prospective observational cohort submitted pre and postinjection samples between January 31, 2022, and July 6, 2022. The peak live virus nAb was measured against Omicron sublineages (BA.1, BA.2, BA.2.12.1, and BA.4), and surrogate neutralization (percent inhibition of angiotensin-converting enzyme 2 receptor binding to full length spike, validated vs live virus) was measured out to 3 months against sublineages, including BA.4/5. With live virus testing, the proportion of SOTRs with any nAb increased against BA.2 (47%-100%; P < .01), BA.2.12.1 (27%-80%; P < .01), and BA.4 (27%-93%; P < .01), but not against BA.1 (40%-33%; P = .6). The proportion of SOTRs with surrogate neutralizing inhibition against BA.5, however, fell to 15% by 3 months. Two participants developed mild severe acute respiratory syndrome-coronavirus-2 infection during follow-up. The majority of fully vaccinated SOTRs receiving T+C PrEP achieved BA.4/5 neutralization, yet nAb activity commonly waned by 3 months postinjection. It is critical to assess the optimal dose and interval of T+C PrEP to maximize protection in a changing variant climate.

SARS-CoV-2 variant evasion of monoclonal antibodies based on in vitro studies

Monoclonal antibodies (mAbs) offer a treatment option for individuals with severe COVID-19 and are especially important in high-risk individuals where vaccination is not an option. Given the importance of understanding the evolution of resistance to mAbs by SARS-CoV-2, we reviewed the available in vitro neutralization data for mAbs against live variants and viral constructs containing spike mutations of interest. Unfortunately, evasion of mAb-induced protection is being reported with new SARS-CoV-2 variants. The magnitude of neutralization reduction varied greatly among mAb-variant pairs. For example, sotrovimab retained its neutralization capacity against Omicron BA.1 but showed reduced efficacy against BA.2, BA.4 and BA.5, and BA.2.12.1. At present, only bebtelovimab has been reported to retain its efficacy against all SARS-CoV-2 variants considered here. Resistance to mAb neutralization was dominated by the action of epitope single amino acid substitutions in the spike protein. Although not all observed epitope mutations result in increased mAb evasion, amino acid substitutions at non-epitope positions and combinations of mutations also contribute to evasion of neutralization. This Review highlights the implications for the rational design of viral genomic surveillance and factors to consider for the development of novel mAb therapies.

The Prevention of COVID-19 in High-Risk Patients Using Tixagevimab-Cilgavimab (Evusheld): Real-World Experience at a Large Academic Center

BACKGROUND

Coronavirus disease 2019 (COVID-19) is associated with increased morbidity and mortality among immunocompromised patients. Tixagevimab-cilgavimab (Tix-Cil) is a combination of 2 monoclonal antibodies approved for the prevention of COVID-19 complications in this high-risk group.

METHODS

We retrospectively reviewed the charts of patients who received Tix-Cil during the Omicron variant period (January 17 to April 23, 2022), with a follow-up period until May 24, 2022. We collected data about patient underlying comorbidities and post Tix-Cil COVID-19 infections, deaths, and hospitalizations.

RESULTS

There were 463 patients with a median age of 68 years, of which 51% were male, 79% White, 13.2% Hispanic, 1.7% Black/African American, and 5.8% identified as Other. A total of 18% had undergone a solid organ transplantation or hematopoietic stem cell transplantation. Only 6/98 (6.1%) had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detected by polymerase chain reaction (PCR) at a median 48 days (interquartile range [IQR] 27.5, 69) follow-up. Forty-two patients (9.1%) were hospitalized, and 4 (0.9%) died, but none were attributed to COVID-19 or Tix-Cil. One hospitalized patient had an incidental, asymptomatic, positive SARS-CoV 2 by PCR. The median days from Tix-Cil administration to non-COVID-19-related hospitalization and death were 30 (IQR 17, 55) and 53 (IQR 18, 91), respectively.

CONCLUSION

Tix-Cil provides protection against COVID-19 complications in immunocompromised patients with suboptimal immune responses to vaccines.

Tixagevimab/Cilgavimab in SARS-CoV-2 Prophylaxis and Therapy: A Comprehensive Review of Clinical Experience

Effective treatments and vaccines against COVID-19 used in clinical practice have made a positive impact on controlling the spread of the pandemic, where they are available. Nevertheless, even if fully vaccinated, immunocompromised patients still remain at high risk of adverse outcomes. This has driven the largely expanding field of monoclonal antibodies, with variable results. Tixagevimab/Cilgavimab (AZD7442), a long-acting antibody combination that inhibits the attachment of the SARS-CoV-2 spike protein to the surface of cells, has proved promising in reducing the incidence of symptomatic COVID-19 or death in high-risk individuals without major adverse events when given as prophylaxis, as well as early treatment. Real-world data confirm the antibody combination's prophylaxis efficacy in lowering the incidence, hospitalization, and mortality associated with COVID-19 in solid organ transplant recipients, patients with immune-mediated inflammatory diseases and hematological malignancies, and patients in B-cell-depleting therapies. Data suggest a difference in neutralization efficiency between the SARS-CoV-2 subtypes in favor of the BA.2 over the BA.1. In treating COVID-19, AZD7442 showed a significant reduction in severe COVID-19 cases and mortality when given early in the course of disease, and within 5 days of symptom onset, without being associated with severe adverse events, even when it is used in addition to standard care. The possibility of the development of spike-protein mutations that resist monoclonal antibodies has been reported; therefore, increased vigilance is required in view of the evolving variants. AZD7442 may be a powerful ally in preventing COVID-19 and the mortality associated with it in high-risk individuals. Further research is required to include more high-risk groups and assess the concerns limiting its use, along the SARS-CoV-2 evolutionary trajectory.

Lessons from SENCOVAC: A prospective study evaluating the response to SARS-CoV-2 vaccination in the CKD spectrum

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has negatively impacted on patients of the whole CKD spectrum, causing high rates of morbi-mortality. SARS-CoV-2 vaccines opened a new era, but patients with CKD (including kidney transplant, hemodialysis and peritoneal dialysis) were systematically excluded from pivotal clinical trials. The Spanish Society of Nephrology promoted the multicentric national SENCOVAC study aimed at assessing immunological responses after vaccination in patients with CKD. During the first year after vaccination, patients with non-dialysis CKD and those on hemodialysis and peritoneal dialysis presented good anti-Spike antibody responses to vaccination, especially after receiving the third and fourth doses. However, kidney transplant recipients presented suboptimal responses after any vaccination schedule (initial, third and fourth dose). Especially worrisome is the situation of a patients with a persistently negative humoral response that do not seroconvert after boosters. In this regard, monoclonal antibodies targeting SARS-CoV-2 have been approved for high-risk patients, although they may become obsolete as the viral genome evolves. The present report reviews the current status of SARS-CoV-2 vaccination in the CKD spectrum with emphasis on lessons learned from the SENCOVAC study. Predictors of humoral response, including vaccination schedules and types of vaccines, as well as the integration of vaccines, monoclonal antibodies and antiviral agents are discussed.

Efficacy and Safety of Tixagevimab/Cilgavimab to Prevent COVID-19 (Pre-Exposure Prophylaxis): A Systematic Review and Meta-Analysis

Background: Tixagevimab/cilgavimab (TGM/CGM) are neutralizing monoclonal antibodies (mAbs) directed against different epitopes of the receptor-binding domain of the SARS-CoV-2 spike protein that have been considered as pre-exposure prophylaxis (PrEP). Objectives: This study seeks to assess the efficacy and safety of TGM/CGM to prevent COVID-19 in patients at high risk for breakthrough and severe SARS-CoV-2 infection who never benefited maximally from SARS-CoV-2 vaccination and for those who have a contraindication to SARS-CoV-2 vaccines. Design: This study is a systematic review and meta-analysis. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was followed. Methods: Electronic databases (PubMed, CINAHL, Embase, medRxiv, ProQuest, Wiley online library, Medline, and Nature) were searched from 1 December 2021 to 30 November 2022 in the English language using the following keywords alone or in combination: 2019-nCoV, 2019 novel coronavirus, COVID-19, coronavirus disease 2019, SARS-CoV-2, severe acute respiratory syndrome coronavirus 2, tixagevimab, cilgavimab, combination, monoclonal, passive, immunization, antibody, efficacy, clinical trial, cohort, pre-exposure, prophylaxis, and prevention. We included studies in moderate to severe immunocompromised adults (aged ≥18 years) and children (aged ≥12 years) who cannot be vaccinated against COVID-19 or may have an inadequate response to SARS-CoV-2 vaccination. The effect sizes of the outcome of measures were pooled with 95% confidence intervals (CIs) and risk ratios (RRs). Results: Of the 76 papers that were identified, 30 articles were included in the qualitative analysis and 13 articles were included in the quantitative analysis (23 cohorts, 5 case series, 1 care report, and 1 randomized clinical trial). Studies involving 27,932 patients with high risk for breakthrough and severe COVID-19 that reported use of TGM/CGM combination were analyzed (all were adults (100%), 62.8% were men, and patients were mainly immunocompromised (66.6%)). The patients’ ages ranged from 19.7 years to 79.8 years across studies. TGM/CGM use was associated with lower COVID-19-related hospitalization rate (0.54% vs. 1.2%, p = 0.27), lower ICU admission rate (0.6% vs. 5.2%, p = 0.68), lower mortality rate (0.2% vs. 1.2%, p = 0.67), higher neutralization of COVID-19 Omicron variant rate (12.9% vs. 6%, p = 0.60), lower proportion of patients who needed oxygen therapy (8% vs. 41.2%, p = 0.27), lower RT-PCR SARS-CoV-2 positivity rate (2.1% vs. 5.8%, p < 0.01), lower proportion of patients who had severe COVID-19 (0% vs. 0.5%, p = 0.79), lower proportion of patients who had symptomatic COVID-19 (1.8% vs. 6%, p = 0.22), and higher adverse effects rate (11.1% vs. 10.7%, p = 0.0066) than no treatment or other alternative treatment in the prevention of COVID-19. Conclusion: For PrEP, TGM/CGM-based treatment can be associated with a better clinical outcome than no treatment or other alternative treatment. However, more randomized control trials are warranted to confirm our findings and investigate the efficacy and safety of TGM/CGM to prevent COVID-19 in patients at risk for breakthrough or severe SARS-CoV-2 infection.

Tixagevimab/cilgavimab for prevention and treatment of COVID-19: a review

INTRODUCTION

There is a need to protect vulnerable individuals who do not respond to vaccination against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), particularly following the emergence of new variants. Tixagevimab/cilgavimab, the only monoclonal antibody combination authorized for pre-exposure prophylaxis of coronavirus disease 2019 (COVID-19), demonstrated efficacy in unvaccinated individuals in the PROVENT study.

AREAS COVERED

This review focuses predominantly on real-world evidence examining the effectiveness and safety of tixagevimab/cilgavimab in populations who are immunocompromised and otherwise vulnerable. The ability of tixagevimab/cilgavimab to neutralize Omicron subvariants, the appropriate dosage in vulnerable populations, and the impact of prior vaccination on tixagevimab/cilgavimab effectiveness are also discussed.

EXPERT OPINION

The tixagevimab/cilgavimab combination is important in providing protection in people who either cannot have a full vaccination or respond poorly to COVID-19 vaccines. Abundant clinical data have emerged to inform clinical use in adults in need, although some additional data-formal pediatric and adolescent studies, plus information on optimal doses required to protect against emerging variants, and the ideal interval between tixagevimab/cilgavimab dosing and vaccination-would be welcomed. Importantly, despite the current effectiveness of tixagevimab/cilgavimab, we must recognize the possibility that resistant SARS-CoV-2 variants could emerge in the future.