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

Effectiveness of full mRNA vaccinations to prevent COVID-19 among immunocompromised patients receiving tixagevimab-cilgavimab as pre-exposure prophylaxis

Pre-exposure prophylaxis with monoclonal antibodies (mAbs) offers protection against COVID-19 in immunocompromised patients. To attest full vaccinations, defined by ≥ 3-dose mRNA vaccines, providing additional protection effect on mAbs against COVID-19, we retrospectively compared the breakthrough SARS-CoV-2 infection rates between adult immunocompromised patients with and without full vaccinations before receiving prophylactic tixagevimab-cilgavimab during the Omicron BA.5 dominant period. Among 148 patients, most (96.6 %) had hematologic malignancies. Fifty-nine (39.9 %) patients received full vaccinations before tixagevimab-cilgavimab. Overall, 19 (12.8 %) patients have breakthrough infections, and only three of them had full vaccinations. By a multivariable logistic regression model, receipt of full vaccinations was the only independent factor associated with prevention of breakthrough infections (adjusted odds ratio, 0.26 [95 % CI, 0.07-0.95]). The Kaplan-Meier estimate showed a lesser trend of breakthrough infections with those receiving full vaccinations (P = 0.08). Our study underscores the importance of full vaccinations among immunocompromised patients receiving pre-exposure prophylactic mAbs against COVID-19.

Risk of Severe COVID-19 in Four Immunocompromised Populations: A French Expert Perspective

Immunocompromised patients are disproportionately impacted by severe disease, hospitalization, and mortality associated with coronavirus disease 2019 (COVID-19). To optimize the management of these patients in clinical practice, we convened an expert panel to review current evidence on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine responses and severe COVID-19 in immunocompromised populations. We identified four main immunocompromised groups-solid organ transplant recipients, patients receiving allogeneic hematopoietic stem cell transplantation or chimeric antigen receptor (CAR) T cell therapy, patients treated for hematologic malignancies, and patients treated for inflammatory diseases-who mount suboptimal humoral responses to SARS-CoV-2 vaccination and are at increased risk of severe COVID-19-related outcomes. A wide range of risk factors were associated with reduced vaccine responses and/or poor outcomes, most commonly older age, comorbidities, and the type and number of immunosuppressive therapies. We believe that early identification and close monitoring of these at-risk patients, plus regular booster vaccinations, prophylactic monoclonal antibody therapy, non-pharmacologic prevention measures, prompt antiviral treatment, and other risk mitigation strategies, are critical to protect against SARS-CoV-2 infection and severe COVID-19.

Plant-produced SARS-CoV-2 antibody engineered towards enhanced potency and in vivo efficacy

Prevention of severe COVID-19 disease by SARS-CoV-2 in high-risk patients, such as immuno-compromised individuals, can be achieved by administration of antibody prophylaxis, but producing antibodies can be costly. Plant expression platforms allow substantial lower production costs compared to traditional bio-manufacturing platforms depending on mammalian cells in bioreactors. In this study, we describe the expression, production and purification of the originally human COVA2-15 antibody in plants. Our plant-produced mAbs demonstrated comparable neutralizing activity with COVA2-15 produced in mammalian cells. Furthermore, they exhibited similar capacity to prevent SARS-CoV-2 infection in a hamster model. To further enhance these biosimilars, we performed three glyco- and protein engineering techniques. First, to increase antibody half-life, we introduced YTE-mutation in the Fc tail; second, optimization of N-linked glycosylation by the addition of a C-terminal ER-retention motif (HDEL), and finally; production of mAb in plant production lines lacking β-1,2-xylosyltransferase and α-1,3-fucosyltransferase activities (FX-KO). These engineered biosimilars exhibited optimized glycosylation, enhanced phagocytosis and NK cell activation capacity compared to conventional plant-produced S15 and M15 biosimilars, in some cases outperforming mammalian cell produced COVA2-15. These engineered antibodies hold great potential for enhancing in vivo efficacy of mAb treatment against COVID-19 and provide a platform for the development of antibodies against other emerging viruses in a cost-effective manner.

Preventing Severe COVID-19 with Tixagevimab-Cilgavimab in Hematological Patients Treated with Anti-CD20 Monoclonal Antibodies: An International Multicenter Study

INTRODUCTION

Despite the declining public health emergency status, COVID-19 still poses significant risks, especially for immunocompromised individuals. We aimed to evaluate the effectiveness of tixagevimab-cilgavimab (T-C) prophylaxis in preventing severe COVID-19 in patients with hematologic malignancies (HM) treated with anti-CD20 therapy during the early Omicron variant phase of the pandemic.

METHODS

The European Society of Clinical Microbiology and Infectious Diseases Study Group for Respiratory Viruses (ESGREV) conducted a multicenter retrospective cohort study involving 15 centers from 5 countries. The study included 749 patients with HM treated with anti-CD20 between February 15 and June 30, 2022, comparing 215 who received T-C prophylaxis to 534 who did not.

RESULTS

The study revealed a significant reduction in the risk of COVID-19 among patients who received T-C prophylaxis compared to those who did not (11.2% vs 23.4%, p < 0.001), with hazard ratio (HR) of 0.40 (95% CI 0.26-0.63), adjusted for age, sex, vaccination status, baseline HM malignancy and type of anti-CD-20. We also demonstrated a reduction for severe-critical diseases within all study populations, 1.4% vs 5.2%, p = 0.017, HR 0.26 (95% CI 0.08-0.84).

CONCLUSION

T-C prophylaxis effectively prevented COVID-19 and severe-critical COVID-19 in patients with HM treated with anti-CD20 monoclonal antibodies during the early Omicron variant phase of the pandemic. Even though T-C is ineffective against current variants, these findings highlight the importance of additional protective measures and the continued development of monoclonal antibodies to protect immunocompromised individuals to mitigate the impact of COVID-19 and other respiratory viral diseases.

Epidemiological Study in Antiviral Innate Immunity

This chapter summarizes the epidemiological study design of natural immune epidemiology studies based on recent COVID-19-related research. The epidemiological studies on antiviral innate immunity have mainly included randomized controlled trials (RCTs) and observational studies. Importantly, this chapter will discuss how to use these methodologies to answer an epidemiological question of natural immunity in the viral infection process based on previous studies. An observational case- or cohort-based study of antiviral innate immunity may support this theoretical hypothesis but is not appropriate for clinical practice or treatment. RCTs are the gold standard for epidemiological studies and occupy a greater role in the hierarchy of evidence.

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.

How Immunocompromised Hosts Were Left Behind in the Quest to Control the COVID-19 Pandemic

The immunocompromised population was disproportionately affected by the severe acute respiratory syndrome coronavirus 2 pandemic. However, these individuals were largely excluded from clinical trials of vaccines, monoclonal antibodies, and small molecule antivirals. Although the community of scientists, clinical researchers, and funding agencies have proven that these therapeutics can be made and tested in record time, extending this progress to vulnerable and medically complex individuals from the start has been a missed opportunity. Here, we advocate that it is paramount to plan for future pandemics by investing in specific clinical trial infrastructure for the immunocompromised population to be prepared when the need arises.

Tolerability and outcomes with rollout of tixagevimab-cilgavimab in patients with common variable immunodeficiency

Background

Tixagevimab-cilgavimab is a combination of 2 mAbs against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In December 2021, the Food and Drug Administration issued Emergency Use Authorization for intramuscular injection of tixagevimab-cilgavimab for prophylaxis against SARS-CoV-2 in immunocompromised patients. Shortly thereafter, our clinic distributed tixagevimab-cilgavimab to patients with common variable immunodeficiency.

Objective

We sought to evaluate the effectiveness and tolerability of tixagevimab-cilgavimab in a common variable immunodeficiency clinic.

Methods

A retrospective chart review from February 1, 2022, to August 1, 2022, of 47 patients with common variable immunodeficiency who were offered tixagevimab-cilgavimab was carried out. Comparative outcomes of treatment and nontreatment groups examined the occurrence of SARS-CoV-2 infection, severity of SARS-CoV-2 infection, and other non-SARS-CoV-2 infections.

Results

Seventy percent of the patients were female; mean age was 49 years. Twenty-three patients received tixagevimab-cilgavimab, and 24 did not receive prophylaxis. In the tixagevimab-cilgavimab group, all were vaccinated for SARS-CoV-2 and 22 were receiving immunoglobulin replacement. One patient was infected with SARS-CoV-2, no patients required emergency care, and 7 patients had non-SARS-CoV-2 infection. In the cohort that did not receive prophylaxis, 21 were vaccinated, and all received immunoglobulin replacement. Two patients tested positive for SARS-CoV-2, 1 patient required emergency care due to SARS-CoV-2 disease severity, and 4 patients had a non-SARS-CoV-2 infection. None of the results showed statistical significance.

Conclusions

Although there is evidence that tixagevimab-cilgavimab can be protective against SARS-CoV-2 in immunocompromised individuals, our data suggest that this benefit may be blunted in patients with common variable immunodeficiency on immunoglobulin replacement. The additional benefit of tixagevimab-cilgavimab in immunocompromised patients already receiving replacement therapy requires further exploration.

Project NextGen: Developing the Next Generation of COVID-19 Vaccines and Therapeutics to Respond to the Present and Prepare for the Future

Coronavirus disease 2019 (COVID-19) epidemiology and product landscapes have changed considerably since onset of the pandemic. Safe and effective vaccines and therapeutics are available, but the continual emergence of severe acute respiratory syndrome coronavirus 2 variants introduce limitations in our ability to prevent and treat disease. Project NextGen is a collaboration between the Biomedical Advanced Research and Development Authority, part of the Administration for Strategic Preparedness and Response, and the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, that is leveraging public-private partnerships to address gaps in the nation's COVID-19 vaccine and therapeutic capabilities. Targeted investments will advance promising next-generation candidates through the most difficult phases of clinical development to encourage further private sector interest for later stage development and commercial availability. New commercial vaccines and therapeutics that are more durable and effective across variants will improve our fight against COVID-19 and transform our response to future threats.

Harnessing immunity: Immunomodulatory therapies in COVID-19

An overly exuberant immune response, characterized by a cytokine storm and uncontrolled inflammation, has been identified as a significant driver of severe coronavirus disease 2019 (COVID-19) cases. Consequently, deciphering the intricacies of immune dysregulation in COVID-19 is imperative to identify specific targets for intervention and modulation. With these delicate dynamics in mind, immunomodulatory therapies have emerged as a promising avenue for mitigating the challenges posed by COVID-19. Precision in manipulating immune pathways presents an opportunity to alter the host response, optimizing antiviral defenses while curbing deleterious inflammation. This review article comprehensively analyzes immunomodulatory interventions in managing COVID-19. We explore diverse approaches to mitigating the hyperactive immune response and its impact, from corticosteroids and non-steroidal drugs to targeted biologics, including anti-viral drugs, cytokine inhibitors, JAK inhibitors, convalescent plasma, monoclonal antibodies (mAbs) to severe acute respiratory syndrome coronavirus 2, cell-based therapies (i.e., CAR T, etc.). By summarizing the current evidence, we aim to provide a clear roadmap for clinicians and researchers navigating the complex landscape of immunomodulation in COVID-19 treatment.

Humoral immunity to SARS-CoV-2 in kidney transplant recipients and dialysis patients: IgA and IgG patterns unraveled after SARS-CoV-2 infection and vaccination

BACKGROUND

Infection with SARS-CoV-2 in high-risk groups such as kidney transplant and dialysis patients is shown to be associated with a more serious course of the disease. Four years after the start of the COVID-19 pandemic, crucial knowledge on the immune responses in these patient groups is still lacking. Therefore, this study aimed at investigating the humoral immune response after a SARS-CoV-2 infection compared to vaccination as well as the evolution of immunoglobulins over time.

METHODS

Kidney transplant recipients, patients on haemodialysis or on peritoneal dialysis and healthy controls were included in this longitudinal multicenter study. SARS-CoV-2 anti-RBD, anti-NP and anti-S1S2 immunoglobulin G (IgG) and A (IgA) as well as the neutralizing antibody capacity were measured.

RESULTS

Kidney transplant recipients had a significantly better humoral response to SARS-CoV-2 after infection (86.4%) than after a two-dose mRNA vaccination (55.8%) while seroconversion was comparable in patients on haemodialysis after infection (95.8%) versus vaccination (89.4%). In individuals without prior COVID-19, the IgG levels after vaccination were significantly lower in kidney transplant recipients when compared to all other groups. However, the IgA titres remained the highest in this patient group at each time point, both after infection and vaccination. A history COVID-19 was associated with higher antibody levels after double-dose vaccination in all patient categories and, while decreasing, titres remained high six months after double-dose vaccination.

CONCLUSION

Kidney transplant recipients had a more robust humoral response to SARS-CoV-2 following infection compared to a two-dose mRNA vaccination, while patients on haemodialysis exhibited comparable seroconversion rates. Notably, individuals with prior COVID-19 exhibited higher IgG levels in response to vaccination. Hybrid immunity is thus the best possible defence against severe COVID-19 disease and seems also to hold up for these populations. Next, it is not clear whether the higher IgA levels in the kidney transplant recipients is beneficial for neutralizing SARS-CoV-2 or if it is a sign of disease severity.

Anti-SARS-CoV-2 glyco-humanized polyclonal antibody XAV-19: phase II/III randomized placebo-controlled trial shows acceleration to recovery for mild to moderate patients with COVID-19

Introduction

XAV-19 is a glyco-humanized swine polyclonal antibody targeting SARS-CoV-2 with high neutralizing activity. The safety and clinical efficacy of XAV-19 were investigated in patients with mild to moderate COVID-19.

Methods

This phase II/III, multicentric, randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the safety and clinical efficacy of XAV-19 in patients with a seven-point WHO score of 2 to 4 at randomization, i.e., inpatients with COVID-19 requiring or not requiring low-flow oxygen therapy, and outpatients not requiring oxygen (EUROXAV trial, NCT04928430). Adult patients presenting in specialized or emergency units with confirmed COVID-19 and giving their consent to participate in the study were randomized to receive 150 mg of XAV-19 or placebo. The primary endpoint was the proportion of patients with aggravation within 8 days after treatment, defined as a worsening of the seven-point WHO score of at least one point between day 8 and day 1 (inclusion). The neutralization activity of XAV-19 against variants circulating during the trial was tested in parallel.

Results

From March 2021 to October 2022, 279 patients received either XAV-19 (N = 140) or placebo (N = 139). A slow enrollment and a low rate of events forced the termination of the premature trial. XAV-19 was well tolerated. Underpowered statistics did not allow the detection of any difference in the primary endpoint between the two groups or in stratified groups. Interestingly, analysis of the time to improvement (secondary endpoint) showed that XAV-19 significantly accelerated the recovery for patients with a WHO score of 2 or 3 (median at 7 days vs. 14 days, p = 0.0159), and even more for patients with a WHO score of 2 (4 days vs. 14 days, p = 0.0003). The neutralizing activity against Omicron and BA.2, BA.2.12.1, BA.4/5, and BQ.1.1 subvariants was shown.

Discussion

In this randomized placebo- controlled trial with premature termination, reduction of aggravation by XAV-19 at day 8 in patients with COVID-19 was not detectable. However, a significant reduction of the time to improvement for patients not requiring oxygen was observed. XAV-19 maintained a neutralizing activity against SARS-CoV-2 variants. Altogether, these data support a possible therapeutic interest for patients with mild to moderate COVID-19 requiring anti-SARS-CoV-2 neutralizing antibodies.

Clinical Trial Registration

https://clinicaltrials.gov/, identifier NCT04928430; https://www.clinicaltrialsregister.eu/about.html (EudraCT), identifier 2020-005979-12.

Increased Risk of Invasive Aspergillosis in Immunocompromised Patients With Persistent SARS-CoV-2 Viral Shedding >8 Weeks, Retrospective Case-control Study

Background

Immunocompromised patients now represent the population most at risk for severe coronavirus disease 2019. Persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral shedding was reported in these patients ranging from several weeks up to 9 months. We conducted a bicentric retrospective case-control study to identify risk and prognostic factors associated with persistent viral shedding in immunocompromised patients.

Material and Methods

Symptomatic immunocompromised adults with persistent SARS-CoV-2 viral shedding >8 weeks were retrospectively included between 1 March 2020 and 24 April 2022 at 2 university hospitals in Paris, France, and matched with a control group consisting of symptomatic immunocompromised patients without persistent viral shedding.

Results

Twenty-nine immunocompromised patients with persistent viral shedding were compared with 40 controls. In multivariate analysis, fever and lymphocytopenia (<0.5 G/L) were associated with an increased risk of persistent viral shedding (odds ratio [OR]: 3.3; 95% confidence interval [CI], 1.01-11.09) P = .048 and OR: 4.3; 95% CI, 1.2-14.7; P = .019, respectively). Unvaccinated patients had a 6-fold increased risk of persistent viral shedding (OR, 6.6; 95% CI, 1.7-25.1; P = .006). Patients with persistent viral shedding were at risk of hospitalization (OR: 4.8; 95 CI, 1.5-15.6; P = .008), invasive aspergillosis (OR: 10.17; 95 CI, 1.15-89.8; P = .037) and death (log-rank test <0.01).

Conclusions

Vaccine coverage was protective against SARS-CoV-2 persistent viral shedding in immunocompromised patients. This new group of immunocompromised patients with SARS-CoV-2 persistent viral shedding is at risk of developing invasive aspergillosis and death and should therefore be systematically screened for this fungal infection for as long as the viral shedding persists.

Vaccination strategies for patients under monoclonal antibody and other biological treatments: an updated comprehensive review based on EMA authorisations to January 2024

INTRODUCTION

Monoclonal antibodies (mAbs) and other biological agents are being increasingly approved in the last years with very different indications. Their highly heterogeneous immunosuppressive effects, mechanisms of action and pharmacokinetics require comprehensive individualized vaccination schedules.

AREAS COVERED

Vaccination for immunocompromised patients. Prevention and treatment with mAbs and other biological therapies.

EXPERT OPINION

Current recommendations on vaccine schedules for patients under mAbs or other biological treatments are based on expert opinions and are not individualized according to each vaccine and treatment. No studies are focusing on the high heterogeneity of these agents, which are exponentially developed and used for many different indications. Recent paradigm changes in vaccine development (boosted by the COVID-19 pandemic) and in the mAbs use for prophylactic purposes (changing 'vaccination' by 'immunization' schedules) has been witnessed in the last years. We aimed at collecting all mAbs used for treatment or prevention, approved as of 1 January 2024, by the EMA. Based on available data on mAbs and vaccines, we propose a comprehensive guide for personalizing vaccination. Recent vaccine developments and current population strategies (e.g. zoster vaccination or prophylactic nirsevimab) are discussed. This review aims to be a practical guideline for professionals working in vaccine consultations for immunosuppressed patients.