Monoclonal Antibody Therapies Against SARS-CoV-2: Promises and Realities.

Monoclonal antibodies targeting the Spike protein of SARS-CoV-2 have been widely deployed in the ongoing COVID-19 pandemic. I review here the impact of those therapeutics in the early pandemic, ranging from structural classification to outcomes in clinical trials to in vitro and in vivo evidence of basal and treatment-emergent immune escape. Unfortunately, the Omicron variant of concern has completely reset all achievements so far in mAb therapy for COVID-19. Despite the intrinsic limitations of this strategy, future developments such as respiratory delivery of further engineered mAb cocktails could lead to improved outcomes.

Efficacy and safety of tixagevimab-cilgavimab versus SARS-CoV-2 breakthrough infection in the hematological conditions.

BACKGROUND: Managing SARS-CoV-2 infection in frail and immunosuppressed patients still represents an open challenge, but, starting from the phase 3 PROVENT study, prophylaxis with tixagevimab-cilgavimab has improved the approach in this category of patients, guaranteeing a better outcome and inferior mortality. Real-life data in a heterogeneous cohort are few. METHODS: The aim of this study is to evaluate the benefit of prophylaxis with tixagevimab-cilgavimab in a cohort of 202 patients affected by different hematological diseases (lymphoproliferative, myeloproliferative, autoimmune, patients recently receiving a bone marrow transplant), active (with ongoing treatment), or in watch-and-wait strategy, followed in our center, during a median follow-up of 249 (45-325) days. RESULTS: An incidence of 44 breakthrough infections (21.8%) is reported, with no treatment-related adverse effects. Age ≥70 years, ongoing treatment (above all with monoclonal antibodies), baseline lymphoproliferative disorders, and prior virus exposure are identified as risk factors related to subsequent infection (p < 0.05). Moreover, the incidence is higher in low/nonresponse to prior vaccination (p = .002). Patients treated with tixagevimab-cilgavimab had a mild course of the infection and a reduction of the duration compared with preprophylaxis infection (11 vs. 15 days, p < .001). The concurrent treatment with anti-CD20 monoclonal antibodies and B-non-Hodgkin lymphoma still confers a higher duration of infection despite prophylaxis. No deaths attributable to the infection occurred. CONCLUSION: Prophylaxis treatment seems to be a valid and safe strategy, although not preventing breakthrough infection, but the severe complications associated with the infection and the possible delays in administering lifesaving therapies from long positivity.

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.

Accelerating therapeutics development during a pandemic: population pharmacokinetics of the long-acting antibody combination AZD7442 (tixagevimab/cilgavimab) in the prophylaxis and treatment of COVID-19.

AZD7442 is a combination of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-neutralizing antibodies, tixagevimab and cilgavimab, developed for pre-exposure prophylaxis (PrEP) and treatment of coronavirus disease 2019 (COVID-19). Using data from eight clinical trials, we describe a population pharmacokinetic (popPK) model of AZD7442 and show how modeling of "interim" data accelerated decision-making during the COVID-19 pandemic. The final model was a two-compartmental distribution model with first-order absorption and elimination, including standard allometric exponents for the effect of body weight on clearance and volume. Other covariates included were as follows: sex, age >65 years, body mass index ≥30 kg/m2, and diabetes on absorption rate; diabetes on clearance; Black race on central volume; and intramuscular (IM) injection site on bioavailability. Simulations indicated that IM injection site and body weight had > 20% effects on AZD7442 exposure, but no covariates were considered to have a clinically relevant impact requiring dose adjustment. The pharmacokinetics of AZD7442, cilgavimab, and tixagevimab were comparable and followed linear kinetics with extended half-lives (median 78.6 days for AZD7442), affording prolonged protection against susceptible SARS-CoV-2 variants. Comparison of popPK simulations based on "interim data" with a target concentration based on 80% viral inhibition and assuming 1.81% partitioning into the nasal lining fluid supported a decision to double the PrEP dosage from 300 mg to 600 mg to prolong protection against Omicron variants. Serum AZD7442 concentrations in adolescents weighing 40-95 kg were predicted to be only marginally different from those observed in adults, supporting authorization for use in adolescents before clinical data were available. In these cases, popPK modeling enabled accelerated clinical decision-making.

Molnupiravir increases SARS-CoV-2 genome diversity and complexity: A case-control cohort study.

Molnupiravir, an oral direct-acting antiviral effective in vitro against SARS-CoV-2, has been largely employed during the COVID-19 pandemic, since December 2021. After marketing and widespread usage, a progressive increase in SARS-CoV-2 lineages characterized by a higher transition/transversion ratio, a characteristic signature of molnupiravir action, appeared in the Global Initiative on Sharing All Influenza Data (GISAID) and International Nucleotide Sequence Database Collaboration (INSDC) databases. Here, we assessed the drug effects by SARS-CoV-2 whole-genome sequencing on 38 molnupiravir-treated persistently positive COVID-19 outpatients tested before and after treatment. Seventeen tixagevimab/cilgavimab-treated outpatients served as controls. Mutational analyses confirmed that SARS-CoV-2 exhibits an increased transition/transversion ratio seven days after initiation of molnupiravir. Moreover we observed an increased G->A ratio compared to controls, which was not related to apolipoprotein B mRNAediting enzyme, catalytic polypeptide-like (APOBEC) activity. In addition, we demonstrated for the first time an increased diversity and complexity of the viral quasispecies.

Breakthrough COVID-19 After Tixagevimab/Cilgavimab Among Patients With Systemic Autoimmune Rheumatic Diseases.

OBJECTIVE: To determine the incidence and baseline factors associated with breakthrough coronavirus disease 2019 (COVID-19) after preexposure prophylaxis (PrEP) with tixagevimab/cilgavimab among patients with systemic autoimmune rheumatic diseases (SARDs). METHODS: We performed a retrospective cohort study among patients with SARDs who received tixagevimab/cilgavimab between January 2, 2022, and November 16, 2022. The primary outcome was breakthrough COVID-19 after tixagevimab/cilgavimab. We performed multivariable Cox regression models adjusted for baseline factors to identify risk factors for breakthrough COVID-19. RESULTS: We identified 444 patients with SARDs who received tixagevimab/cilgavimab (mean age 62.0 years, 78.2% female). There were 83 (18.7%) breakthrough COVID-19 cases (incidence rate 31.5/1000 person-months, 95% CI 24.70-38.24), 7 (1.6%) hospitalizations, and 1 (0.2%) death. Older age was inversely associated with breakthrough COVID-19 (adjusted hazard ratio [aHR] 0.86/10 years, 95% CI 0.75-0.99). Higher baseline spike antibody levels were associated with lower risk of breakthrough COVID-19 (aHR 0.42, 95% CI 0.18-0.99 for spike antibody levels > 200 vs < 0.4 units). CD20 inhibitor users had a similar risk of breakthrough COVID-19 (aHR 1.05, 95% CI 0.44-2.49) compared to conventional synthetic disease-modifying antirheumatic drug (DMARD) users. CONCLUSION: We found that patients with SARDs had frequent breakthrough COVID-19, but the proportion experiencing severe COVID-19 was low. DMARD type, including CD20 inhibitors, did not significantly affect risk of breakthrough COVID-19. Evidence of prior humoral immunity was protective against breakthrough infection, highlighting the continued need for a multimodal approach to prevent severe COVID-19 as novel PrEP therapies are being developed.

Tixagevimab/cilgavimab (AZD7442/Evusheld) prevent from COVID19 in patients with hematologic malignancies under active chemotherapy.

Despite the efficacy of COVID-19 vaccines, patients with hematologic malignancy may still be fatal from COVID19. Therefore, we prospectively performed the analysis of administration of tixagevimab/cilgavimab in the real-world. In August 2022, 94 patients under active chemotherapy for lymphoma, multiple myeloma, or acute leukemia received a single dose AZD7442/Evusheld (two consecutive intramuscular injections of tixagevimab and cilgavimab, 300 mg each). Quantitative measurement of anti-SARS-CoV-2 spike protein (anti-S) and viral nucleocapsid (anti-N) titers were conducted before administration of tixagevimab/cilgavimab and at 1, 3, and 6 months after administration. Twenty-five patients (26.6%) had previously confirmed COVID-19 infection. Fifty-eight patients (61.7%) had previously received COVID-19 vaccinations, with a median of two doses (range, 1-5). The median anti-S Ab level increased from baseline (997.05 AU/mL) to 1 month (20,967.25 AU/mL), then decreased at 3 months (13,145.0 AU/mL), and 6 months (7123.0 AU/mL) (p < 0.001). There was no significant safety issue with tixagevimab/cilgavimab. With a median follow-up time of 6 months, thirteen patients (13.8%) had documented SARS-Cov-2 infection. A 20.2% rate of anti-N positivity was observed six months after the administration of tixagevimab/cilgavimab. The results of this study support the potential role of tixagevimab/cilgavimab for the prevention of symptomatic and severe COVID-19.Trial registration: KCT0007617; August 16, 2022.

Effectiveness of tixagevimab/cilgavimab in patients with hematological malignancies as a pre-exposure prophylaxis to prevent severe COVID-19: a Czech retrospective multicenter study.

Despite lower virulence, the omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) still poses a relevant threat for immunocompromised patients. A retrospective multicentric study was conducted to evaluate the efficacy of pre-exposure prophylaxis with tixagevimab/cilgavimab (Evusheld) with a 6-month follow-up for preventing severe COVID-19 in adult patients with hematology malignancy. Among the 606 patients in the cohort, 96 (16%) contracted COVID-19 with a median of 98.5 days after Evusheld administration. A total of 75% of patients had asymptomatic or mild severity of COVID-19, while just 25% of patients with SARS-CoV-2 positivity had to be hospitalized. Two patients (2%) died directly, and one patient (1%) in association with COVID-19. Eight patients (1.3%) of every cohort experienced adverse events related to Evusheld, mostly grade 1 and of reversible character. It was found that complete vaccination status or positive seroconversion was not associated with lower risk of COVID-19 infection. Previous treatment with an anti-CD20 monoclonal antibody was associated with higher rates of COVID-19, while previous treatment with anti-CD38 monoclonal antibody was not, as was the case for recipients of hematopoietic stem cell transplantation or CAR-T cell therapy. Presence of other comorbidities was not associated with more severe COVID-19. The results support the growing evidence for Evusheld's efficacy against severe COVID-19 in patients with hematology malignancies.

Efficacy and safety of tixagevimab/cilgavimab as passive immunisation against COVID-19 infections in patients with hematological malignancies.

Monoclonal antibodies, as tixagevimab/cilgavimab, have been introduced as prophylaxis against COVID-19 infections in high-risk populations. However, data on efficacy are limited. This study investigates efficacy and tolerability of tixagevimab/cilgavimab in hematological patients under real-life conditions. Tixagevimab/cilgavimab was administered to 155 hematological patients (March-August 2022) at two Austrian centres. S/RBD-antibody assessments were performed before (T0), four weeks (T1), and six months (T2) after application. Side effects, the occurrence of COVID-19 infections, and the course of S/RBD-antibody titres were analysed retrospectively in relation to clinical variables. 155 hematological patients, who refused tixagevimab/cilgavimab, were included as a control group to compare the frequency of COVID-19 infections. Of all immunised patients (52.3% males; 91% triple vaccinated), 25.8% had a COVID-19 breakthrough infection (76% mild) compared to 43.9% in the control group. Patients with chronic lymphocytic leukaemia (CLL)/lymphoma were at highest risk of a COVID-19 infection (OR = 2.21; 95% CI 1.05-4.65; p = 0.037). After immunisation, a steep increase in median antibody levels (1193.4BAU/ml, IQR 0-2318.94) was observed in 67.8%, followed by a rapid decrease between T1 and T2 (465.95BAU/ml, IQR 0-1900.65.3) with the greatest declines in CLL/lymphoma (848.7BAU/ml, IQR 0-1949.6, p = 0.026). Side-effects occurred in 21.2% (CTCAE I/II). These real-world data indicate that S/RBD antibodies respond rapidly after passive immunisation in all hematological patients without safety concerns. Given the rapid decline in S/RBD antibodies, early booster immunisations should be considered for future scenarios in this vulnerable group.

Comprehensive procedure for injecting Evusheld® for hematological diseases in a single institute.

Tixagevimab and cilgavimab (EVA, Evusheld®), monoclonal antibody combination treatments, consisted of two neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). EVA showed prophylactic and therapeutic effects against coronavirus disease 2019. The Japanese Society of Hematology recommended EVA for such patients with active treatment, but each institution decided on comprehensive administration. We develop a systematic procedure for comprehensive EVA injection prophylactically in patients with hematological malignancies without any over/under-indication. We listed all patients with the required indications from November 2022 to March 2023. We included 178 cases, 84 females and 94 males, with a median age of 70 (range: 19-90) years. Underlying diseases are myeloid neoplasms in 36 (20%), lymphoid neoplasms in 75 (73%), and others. Indications were intensively hematological malignancy treatment, rituximab treatment within 12 months, burton kinase inhibitor treatment, after chimeric antigen receptor T cell immunotherapy, and after stem cell transplantation in 74 (41%), 73 (41%), 3 (2%), 5 (3%), and 23 (13%) cases, respectively. Of the 178 cases, 22 (12.4%) refused EVA injection. Further, 42 and 136 cases were administered outpatient and inpatient, respectively. Over 95% of the listed cases received EVA injection within 3 months. No severe toxicities were observed among them (N = 156), and 8 (5.2%) cases had breakthrough SARS-CoV-2 infection, which was significantly lower (P = 0.02) than those without EVA (4 [18.2%] of 22 cases). Both groups showed no moderate or severe infection cases. This single-center experience showed that comprehensive EVA injection management effectively generated safer completion with preferable clinical impact.

Tixagevimab/cilgavimab for the prevention of COVID-19 in solid organ transplant recipients.

Tixagevimab/cilgavimab (tix/cil) received emergency use authorization in December 2021 for pre-exposure prophylaxis against COVID-19 in moderately to severely immunocompromised patients. Our study aimed to describe the incidence of COVID-19 infection and assess the immunologic risks associated with tix/cil in kidney, pancreas, liver, and heart transplant recipients. Retrospective chart review was completed to provide descriptive analysis. Outcomes data included COVID-19 infection, severity of COVID-19 infection, graft function, and rejection. Safety outcomes included cardiovascular (CV) and hypersensitivity events post tix/cil administration. A total of 410 transplant patients were included in the analysis: 20 heart, 92 liver, 243 kidney, 25 simultaneous pancreas/kidney, 23 simultaneous liver/kidney, and seven simultaneous heart/kidney. Twenty-seven (6.5%) patients tested positive for COVID-19 via PCR or antigen test post tix/cil. No apparent difference was observed in patients testing positive for COVID-19 by type of organ transplant (p = .122). Twenty-five of the 27 patients testing positive for COVID-19 reported symptomatic infection, only nine of whom were hospitalized. No patients were mechanically ventilated and no deaths due to COVID-19 occurred. No significant changes in graft function were observed. Clinically significant rejection was diagnosed and treated in four patients. COVID-19 breakthrough infection rates remained low in immunocompromised solid organ transplant recipients who received tix/cil. No significant immunologic risks were observed.

SARS-CoV-2 Vaccination Rates and Uptake of Tixagevimab-Cilgavimab Among a Cohort of Pediatric Solid Organ Transplant Recipients.

INTRODUCTION: There is a lack of data regarding SARS-CoV-2 vaccination rates and tixagevimab-cilgavimab (TC) uptake among pediatric solid organ transplant recipients. The purpose of our study was to assess these rates. MATERIALS AND METHODS: We reviewed vaccination records of pediatric recipients of heart, kidney, and liver transplants at Mayo Clinic, Rochester, MN, who received a transplant between January 2011 and December 2021. All SARS-CoV-2 vaccines and doses of TC received on or before September 1, 2022, the date of approval of the bivalent SARS-CoV2 vaccine, were included. We also assessed whether patients had been seen by an infectious diseases physician (ID) in the preceding 6 months. RESULTS: Our study included 110 patients: 47 kidney, 36 heart, and 27 liver transplant recipients. All vaccine doses recorded were monovalent SARS-CoV-2 vaccines. Sixty-eight (61.8%) patients received at least one vaccine. This varied by age group, with f of ≥12 years olds, 40.9% of 5-11 year olds and 14.3% of under 5 year olds (p = 0.001). Seven patients (6.4%) were up-to-date (UTD) for age. There was no difference in UTD status by organ type (p = 0.335). Patients who saw ID were significantly more likely to be UTD (13.2% versus 2.8%; p = 0.047). Among those eligible, 14 (18.2%) received TC, with rates not different based on transplanted organ type (p = 0.158) or whether they saw ID (p = 0.273). CONCLUSIONS: Despite the availability of vaccines, nearly 40% of pediatric solid organ transplant recipients remained unvaccinated against SARS-CoV-2 at time of the bivalent vaccine release. Less than a fifth of eligible patients received TC. Strategies to increase uptake of SARS-CoV-2 vaccines as well as adjunctive agents among this vulnerable group should be further explored.

COVID-19 Outcomes in Lung Transplant Recipients Following Pre-Exposure Prophylaxis With Tixagevimab-Cilgavimab During the Omicron BA.5 Surge: A Single Center Analysis.

Lung transplant (LTx) recipients are at high risk for COVID-19 related morbidity and mortality. Data regarding pre-exposure prophylaxis (PrEP) with tixagevimab-cilgavimab in this population are scarce. We therefore evaluated COVID-19 breakthrough infections and COVID-19 related complications after PrEP in a retrospective single-center study, including 264 LTx recipients who received PrEP between June 2022 and December 2022, when Omicron BA.5 was the dominant circulating SARS-CoV-2 variant. PrEP was indicated for fully vaccinated patients with poor seroconversion (anti-S <260 BAU/mL). COVID-19 breakthrough infection after PrEP occurred in 11.0% within the first 3 months, increasing to 17.4% within 6 months. Hospitalization rate rose from 27.6% to 52.9% (p = 0.046), while ICU admissions and COVID-19 mortality remained low, respectively occurring in 6.5% and 4.3% of patients with breakthrough infection within 6 months. COVID-19 breakthrough infection and associated hospitalization remained an important problem during the Omicron BA.5 surge in fully vaccinated LTx recipients with deficient seroconversion, despite PrEP with tixagevimab-cilgavimab. However, ICU admissions and COVID-19 mortality were low. Waning of neutralizing effects of PrEP and changing circulating SARS-CoV-2 variants may explain increases in COVID-19 infections and hospitalizations over time after PrEP, highlighting the need for novel, long-term effective PrEP strategies in these high-risk patients.

Investigation of severe acute respiratory syndrome coronavirus 2 infection status in solid organ transplant recipients treated with tixagevimab/cilgavimab.

INTRODUCTION: Tixagevimab and cilgavimab (T/C) are neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can be used to prevent SARS-CoV-2 infection in solid organ transplant (SOT) recipients. However, their neutralizing activity against recent variants was reduced, raising concerns regarding the emergence of breakthrough coronavirus diseases 2019 (COVID-19). This study aimed to investigate the status of the COVID-19 breakthrough after T/C administration. METHODS: We retrospectively investigated breakthrough COVID-19 in SOT recipients administered T/C at Kyoto University Hospital, Japan, from November 2022 to March 2023. Patients were monitored for 6 months after T/C administration. SARS-CoV-2 infection was diagnosed using polymerase chain reaction or antigen tests. The monthly incidence rates of SARS-CoV-2 infection were calculated using the person-time method. RESULTS: T/C were administered to 67 SOT recipients (liver, 16; lung, 36; and kidney, 15), of whom five were infected with SARS-CoV-2. All five cases were classified as mild, and none of these patients required admission to the intensive care unit (ICU) or died. All infected individuals tested positive for SARS-CoV-2 after March 2023, when T/C-resistant subvariant strains became predominant. The monthly incidence rate of SARS-CoV-2 infection, calculated using the person-time method, suggested an increasing trend. CONCLUSIONS: During the T/C-resistant variant epidemic, SARS-CoV-2 infections were identified even after T/C administration, suggesting that the prophylactic effects of T/C were invalid. Therefore, emerging variants must be carefully monitored and characterized to determine appropriate antiviral strategies, such as the use of suitable neutralizing antibodies.

Clinical characteristics and COVID-19-related outcomes of immunocompromised patients receiving tixagevimab/cilgavimab pre-exposure prophylaxis in Japan.

OBJECTIVE: Tixagevimab/cilgavimab is a cocktail of two long-acting monoclonal antibodies approved for pre-exposure prophylaxis (PrEP) of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection (cause of coronavirus disease 2019 [COVID-19]) in immunocompromised (IC) or high-risk patients. We investigated the patient characteristics and clinical outcomes of IC patients administered tixagevimab/cilgavimab for PrEP in real-world use in Japan. METHODS: This observational study used anonymous secondary data from Real-World Data Co., Ltd. for IC patients aged ≥12 years administered tixagevimab/cilgavimab between September 2022 and September 2023. We analyzed the baseline characteristics and event-rates of COVID-19-related clinical outcomes within 6 months of administration. RESULTS: Data were analyzed for 397 IC patients. About half (53.4 %) were male and the median age was 71.0 (interquartile range 61.0, 77.0) years. Malignancy (97.2 %), cardiovascular disease (71.3 %), and diabetes (66.5 %) were frequent comorbidities. Systemic corticosteroids and immunosuppressants were prescribed to 87.4 % and 24.9 %, respectively. The two most common target clinical conditions were active therapy for hematologic malignancies (88.2 %) and treatment with B cell-depleting therapies (57.4 %). The event-rates per 100 person-months (95 % confidence interval; number) for medically attended COVID-19, COVID-19 hospitalization, in-hospital mortality due to COVID-19, and all-cause death were 4.14 (3.06-5.48; n = 49), 1.74 (1.09-2.64; n = 22), 0.07 (0.00-0.42; n = 1), and 0.60 (0.26-1.17; n = 8), respectively. CONCLUSION: This is the first report using a multicenter database to describe the clinical characteristics and COVID-19-related outcomes of IC patients administered with tixagevimab/cilgavimab in real-world settings in Japan. This cohort of IC patients who received tixagevimab/cilgavimab included many elderly patients with comorbidities.

Analysis of SARS-CoV-2 mutations associated with resistance to therapeutic monoclonal antibodies that emerge after treatment.

The mutation rate of the Omicron sublineage has led to baseline resistance against all previously authorized anti-Spike monoclonal antibodies (mAbs). Nevertheless, in case more antiviral mAbs will be authorized in the future, it is relevant to understand how frequently treatment-emergent resistance has emerged so far, under different combinations and in different patient subgroups. We report the results of a systematic review of the medical literature for case reports and case series for treatment-emergent immune escape, which is defined as emergence of a resistance-driving mutation in at least 20% of sequences in a given host at a given timepoint. We identified 32 publications detailing 216 cases that included different variants of concern (VOC) and found that the incidence of treatment emergent-resistance ranged from 10% to 50%. Most of the treatment-emergent resistance events occurred in immunocompromised patients. Interestingly, resistance also emerged against cocktails of two mAbs, albeit at lower frequencies. The heterogenous therapeutic management of those cases doesn't allow inferences about the clinical outcome in patients with treatment-emergent resistance. Furthermore, we noted a temporal correlation between the introduction of mAb therapies and a subsequent increase in SARS-CoV-2 sequences across the globe carrying mutations conferring resistance to that mAb, raising concern as to whether these had originated in mAb-treated individuals. Our findings confirm that treatment-emergent immune escape to anti-Spike mAbs represents a frequent and concerning phenomenon and suggests that these are associated with mAb use in immunosuppressed hosts.

Safety of intramuscular tixagevimab-cilgavimab (Evusheld®) administration in patients at risk of iatrogenic haematoma due to haematological disorders.

INTRODUCTION: Traditionally, intramuscular (IM) injections have been avoided in patients with haematological diseases due to the risk of iatrogenic haematoma. Tixagevimab-cilgavimab (Evusheld®) is a novel monoclonal antibody combination used as preexposure prophylaxis against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), for those at highest risk of severe infections. It is delivered as two separate IM injections (1.5 mL each). Patients with haematological disease are at higher risk for severe SARS-CoV-2 infections, which may be partially abrogated by the prophylactic inoculation of tixagevimab-cilgavimab. METHODS: A combined retrospective and prospective study of patients under the haematology service at a large metropolitan hospital receiving tixagevimab-cilgavimab was conducted. Tixagevimab-cilgavimab was administered IM to all patients, with platelet and factor replacement provided according to local protocols. Patients completed a numerical pain score daily for seven days following the injection, with scores ≥4/10 prompting an ultrasound to identify iatrogenic gluteal haematomas. RESULTS: The study recruited 131 patients; 66 patients were thrombocytopenic, including 10 patients with a platelet count <30 × 109/L. Fourteen patients (10.7%) received a single platelet transfusion prior to tixagevimab-cilgavimab administration, while two patients received fresh frozen plasma. No gluteal haematomas were identified, and only two patients reported an initial pain score of ≥4/10. CONCLUSIONS: The intramuscular administration of tixagevimab-cilgavimab in patients with haematological diseases was well tolerated and was not associated with iatrogenic haematoma.

Breakthrough SARS-CoV-2 Infections in the PROVENT Prevention Trial Were Not Associated With AZD7442 (Tixagevimab/Cilgavimab) Resistant Variants.

BACKGROUND: We 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. METHODS: Variants 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. RESULTS: At 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. CONCLUSIONS: Symptomatic COVID-19 breakthrough cases in PROVENT were not due to resistance-associated substitutions in AZD7442 binding sites or lack of AZD7442 exposure. CLINICAL TRIALS REGISTRATION: NCT04625725.

Cardiovascular Outcomes After Tixagevimab and Cilgavimab use for Pre-Exposure Prophylaxis Against Coronavirus Disease 2019: A Population-Based Propensity-matched Cohort Study.

Tixagevimab and cilgavimab treatment was associated with higher rates of cardiovascular events in a post hoc analysis of a phase 3 trial. In this large population-based propensity-matched study, we found no increased risk of cardiovascular events up to 90 days after tixagevimab and cilgavimab administration, including in patients with pre-existing cardiovascular disease.

Association Between AZD7442 (Tixagevimab-Cilgavimab) Administration and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, Hospitalization, and Mortality.

BACKGROUND: Intramuscular AZD7442 (tixagevimab-cilgavimab [Evusheld; AstraZeneca]) has been found effective among immunocompromised individuals (ICIs) in reducing SARS-CoV-2 infection and severe disease in ICIs. We evaluated the association between AZD7442 administration and SARS-CoV-2 infection and severe disease (COVID-19 hospitalization and all-cause mortality) among selected ICIs, during a fifth Omicron-dominated wave of COVID-19 (December 2021-April 2022) in Israel. METHODS: ICIs aged ≥12 years identified in the Maccabi HealthCare Services database were invited by SMS/e-mail to receive AZD7442. Demographic information, comorbidities, coronavirus vaccination, and prior SARS-CoV-2 infection and COVID-19 outcome data (infection, severe disease) were extracted from the database. Rates of infection and severe disease were compared between those administered AZD7442 and those who did not respond to the invitation over a 3-month period. RESULTS: Of all 825 ICIs administered AZD7442, 29 (3.5%) became infected with SARS-CoV-2 compared with 308 (7.2%) of 4299 ICIs not administered AZD7442 (P < .001). After adjustment, the AZD7442 group was half as likely to become infected with SARS-CoV-2 than the nonadministered group (OR: .51; 95% CI: .30-.84). One person in the AZD7442 group (0.1%) was hospitalized for COVID-19 compared with 27 (0.6%) in the nonadministered group (P = .07). No mortality was recorded among the AZD7442 group compared with 40 deaths (0.9%) in the nonadministered group (P = .005). After adjustment, ICIs administered AZD7442 were 92% less likely to be hospitalized/die than those not administered AZD7442 (OR: .08; 95% CI: .01-.54). CONCLUSIONS: AZD7442 among ICIs may protect against Omicron variant infection and severe disease and should be considered for pre-exposure prophylactic AZD7442.