A phase 1 study in healthy volunteers to investigate the safety, tolerability, and pharmacokinetics of VIR-2482: a monoclonal antibody for the prevention of severe influenza A illness.

The objective of this study was to evaluate the safety, tolerability, pharmacokinetics (PK), and immunogenicity of VIR-2482 in healthy adult subjects. A phase 1, first-in-human, randomized, double-blind, placebo-controlled dose-escalation study was conducted. One hundred participants were allocated to four cohorts (60 mg, 300 mg, 1,200 mg, and 1,800 mg). In each cohort, participants were randomized in a 4:1 ratio (active:placebo) to receive either VIR-2482 or volume-matched placebo by gluteal intramuscular injection. Participants remained at the investigative site under observation for 48 h, and adverse events (AEs) were collected for 56 days. PK and immunogenicity were measured up to 52 weeks post-dose. VIR-2482 was well tolerated at all doses studied. The overall incidence of AEs was comparable between VIR-2482 (68.8%) and placebo (85.0%). Nineteen VIR-2482 (23.8%) and six placebo (30.0%) recipients had Grade 1 or 2 AEs that were considered to be related to the study intervention. There were no treatment-related serious AEs. Injection-site reactions (ISRs) were reported in six (7.5%) VIR-2482 recipients, while no such reactions were reported among the placebo recipients. All ISRs were Grade 1, and there was no relationship with the dose. Median VIR-2482 serum elimination half-life ranged from 56.7 to 70.6 days across cohorts. The serum area under the curve and Cmax were dose-proportional. Nasopharyngeal VIR-2482 concentrations were approximately 2%-5% of serum levels and were less than dose-proportional. The incidence of immunogenicity across all cohorts was 1.3%. Overall, the safety, tolerability, and pharmacokinetic profile of VIR-2482 at doses up to 1,800 mg supported its further investigation as a long-acting antibody for the prevention of influenza A illness. This study has been registered at ClinicalTrials.gov under identifier NCT04033406.

Effect of Sotrovimab on Hospitalization or Death Among High-risk Patients With Mild to Moderate COVID-19: A Randomized Clinical Trial.

Importance: Older patients and those with comorbidities who are infected with SARS-CoV-2 may be at increased risk of hospitalization and death. Sotrovimab is a neutralizing antibody for the treatment of high-risk patients to prevent COVID-19 progression. Objective: To evaluate the efficacy and adverse events of sotrovimab in preventing progression of mild to moderate COVID-19 to severe disease. Design, Setting, and Participants: Randomized clinical trial including 1057 nonhospitalized patients with symptomatic, mild to moderate COVID-19 and at least 1 risk factor for progression conducted at 57 sites in Brazil, Canada, Peru, Spain, and the US from August 27, 2020, through March 11, 2021; follow-up data were collected through April 8, 2021. Interventions: Patients were randomized (1:1) to an intravenous infusion with 500 mg of sotrovimab (n = 528) or placebo (n = 529). Main Outcomes and Measures: The primary outcome was the proportion of patients with COVID-19 progression through day 29 (all-cause hospitalization lasting >24 hours for acute illness management or death); 5 secondary outcomes were tested in hierarchal order, including a composite of all-cause emergency department (ED) visit, hospitalization of any duration for acute illness management, or death through day 29 and progression to severe or critical respiratory COVID-19 requiring supplemental oxygen or mechanical ventilation. Results: Enrollment was stopped early for efficacy at the prespecified interim analysis. Among 1057 patients randomized (median age, 53 years [IQR, 42-62], 20% were ≥65 years of age, and 65% Latinx), the median duration of follow-up was 103 days for sotrovimab and 102 days for placebo. All-cause hospitalization lasting longer than 24 hours or death was significantly reduced with sotrovimab (6/528 [1%]) vs placebo (30/529 [6%]) (adjusted relative risk [RR], 0.21 [95% CI, 0.09 to 0.50]; absolute difference, -4.53% [95% CI, -6.70% to -2.37%]; P < .001). Four of the 5 secondary outcomes were statistically significant in favor of sotrovimab, including reduced ED visit, hospitalization, or death (13/528 [2%] for sotrovimab vs 39/529 [7%] for placebo; adjusted RR, 0.34 [95% CI, 0.19 to 0.63]; absolute difference, -4.91% [95% CI, -7.50% to -2.32%]; P < .001) and progression to severe or critical respiratory COVID-19 (7/528 [1%] for sotrovimab vs 28/529 [5%] for placebo; adjusted RR, 0.26 [95% CI, 0.12 to 0.59]; absolute difference, -3.97% [95% CI, -6.11% to -1.82%]; P = .002). Adverse events were infrequent and similar between treatment groups (22% for sotrovimab vs 23% for placebo); the most common events were diarrhea with sotrovimab (n = 8; 2%) and COVID-19 pneumonia with placebo (n = 22; 4%). Conclusions and Relevance: Among nonhospitalized patients with mild to moderate COVID-19 and at risk of disease progression, a single intravenous dose of sotrovimab, compared with placebo, significantly reduced the risk of a composite end point of all-cause hospitalization or death through day 29. The findings support sotrovimab as a treatment option for nonhospitalized, high-risk patients with mild to moderate COVID-19, although efficacy against SARS-CoV-2 variants that have emerged since the study was completed is unknown. Trial Registration: ClinicalTrials.gov Identifier: NCT04545060.

Outcomes of patients with detectable CMV DNA at randomization in the phase III trial of letermovir for the prevention of CMV infection in allogeneic hematopoietic cell transplantation.

Letermovir, a cytomegalovirus (CMV) terminase-complex inhibitor, is indicated for prophylaxis of CMV infection and disease in adult CMV-seropositive recipients of allogeneic hematopoietic cell transplantation (HCT). In a phase III, double-blind, randomized trial, letermovir significantly reduced the risk of clinically significant CMV infection (CS-CMVi) vs placebo through Week 24 post-HCT. This analysis investigated outcomes in participants with detectable CMV DNA at randomization, who were excluded from the primary efficacy analysis. In total, 70 of 565 randomized participants had detectable CMV DNA at randomization (letermovir 48; placebo 22). Study treatment completion rates were greater in letermovir-treated participants compared with placebo (52.1% vs 9.1%). The incidence of CS-CMVi or imputed primary endpoint events through Week 24 were 64.6% and 90.9% in the letermovir and placebo groups, respectively (treatment difference -26.1%; P = .010). Kaplan-Meier event rates for CS-CMVi onset through Week 14 (end-of-treatment period) were 33.1% for letermovir and 86.6% for placebo (P < .001). Median viral loads at the CS-CMVi events was similar in both treatment arms. All-cause mortality through Week 24 posttransplant was 15.0% for letermovir and 18.2% for placebo; through Week 48, mortality rates were 26.5% and 40.9%, respectively (P = .268). Overall, clinical outcomes were similar to those reported for participants with undetectable CMV DNA at randomization.

Pharmacokinetic Interactions between the Hepatitis C Virus Inhibitors Elbasvir and Grazoprevir and HIV Protease Inhibitors Ritonavir, Atazanavir, Lopinavir, and Darunavir in Healthy Volunteers.

The combination of the hepatitis C virus (HCV) nonstructural protein 5A (NS5A) inhibitor elbasvir and the NS3/4A protease inhibitor grazoprevir is a potent, once-daily therapy indicated for the treatment of chronic HCV infection in individuals coinfected with human immunodeficiency virus (HIV). We explored the pharmacokinetic interactions of elbasvir and grazoprevir with ritonavir and ritonavir-boosted HIV protease inhibitors in three phase 1 trials. Drug-drug interaction trials with healthy participants were conducted to evaluate the effect of ritonavir on the pharmacokinetics of grazoprevir (n = 10) and the potential two-way pharmacokinetic interactions of elbasvir (n = 30) or grazoprevir (n = 39) when coadministered with ritonavir-boosted atazanavir, lopinavir, or darunavir. Coadministration of ritonavir with grazoprevir increased grazoprevir exposure; the geometric mean ratio (GMR) for grazoprevir plus ritonavir versus grazoprevir alone area under the concentration-time curve from 0 to 24 h (AUC0-24) was 1.91 (90% confidence interval [CI]; 1.31 to 2.79). Grazoprevir exposure was markedly increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for grazoprevir AUC0-24 of 10.58 (90% CI, 7.78 to 14.39), 12.86 (90% CI, 10.25 to 16.13), and 7.50 (90% CI, 5.92 to 9.51), respectively. Elbasvir exposure was increased with coadministration of atazanavir-ritonavir, lopinavir-ritonavir, and darunavir-ritonavir, with GMRs for elbasvir AUC0-24 of 4.76 (90% CI, 4.07 to 5.56), 3.71 (90% CI, 3.05 to 4.53), and 1.66 (90% CI, 1.35 to 2.05), respectively. Grazoprevir and elbasvir had little effect on atazanavir, lopinavir, and darunavir pharmacokinetics. Coadministration of elbasvir-grazoprevir with atazanavir-ritonavir, lopinavir-ritonavir, or darunavir-ritonavir is contraindicated, owing to an increase in grazoprevir exposure. Therefore, HIV treatment regimens without HIV protease inhibitors should be considered for HCV/HIV-coinfected individuals who are being treated with elbasvir-grazoprevir.

Assessment of drug interaction potential between the HCV direct-acting antiviral agents elbasvir/grazoprevir and the HIV integrase inhibitors raltegravir and dolutegravir.

BACKGROUND: Elbasvir/grazoprevir is a once-daily fixed-dose combination therapy for the treatment of chronic HCV infection, including HCV/HIV coinfection. OBJECTIVES: To evaluate the pharmacokinetic interaction of elbasvir and grazoprevir with raltegravir or dolutegravir. METHODS: Three open-label trials in healthy adult participants were conducted. In the raltegravir trials, participants received a single dose of raltegravir 400 mg, a single dose of elbasvir 50 mg or grazoprevir 200 mg, and raltegravir with either elbasvir or grazoprevir. In the dolutegravir trial, participants received a single dose of dolutegravir 50 mg alone or co-administered with once-daily elbasvir 50 mg and grazoprevir 200 mg. RESULTS: The raltegravir AUC0-∞ geometric mean ratio (GMR) (90% CI) was 1.02 (0.81-1.27) with elbasvir and 1.43 (0.89-2.30) with grazoprevir. Dolutegravir AUC0-∞ GMR (90% CI) was 1.16 (1.00-1.34) with elbasvir and grazoprevir. The elbasvir AUC0-∞ GMR (90% CI) was 0.81 (0.57-1.17) with raltegravir and 0.98 (0.93-1.04) with dolutegravir. The grazoprevir AUC0-24 GMR (90% CI) was 0.89 (0.72-1.09) with raltegravir and 0.81 (0.67-0.97) with dolutegravir. CONCLUSIONS: Elbasvir or grazoprevir co-administered with raltegravir or dolutegravir resulted in no clinically meaningful drug-drug interactions and was generally well tolerated. These results support the assertion that no dose adjustments for elbasvir, grazoprevir, raltegravir or dolutegravir are needed for co-administration in HCV/HIV-coinfected people.

Efficacy and safety of ruzasvir 60 mg and uprifosbuvir 450 mg for 12 weeks in adults with chronic hepatitis C virus genotype 1, 2, 3, 4 or 6 infection.

In clinical trials, the three-drug regimen of ruzasvir (RZR) 60 mg, uprifosbuvir (UPR) 450 mg and grazoprevir 100 mg, with or without ribavirin, has demonstrated promising efficacy and excellent tolerability across a wide range of hepatitis C virus (HCV)-infected individuals. The present study assessed the efficacy and safety of the two-drug combination of RZR 60 mg plus UPR 450 mg administered for 12 weeks in participants with HCV genotype (GT) 1-6 infection. In this open-label clinical trial, treatment-naive or -experienced and cirrhotic or noncirrhotic participants with chronic HCV GT1-6 infection received RZR 60 mg plus UPR 450 mg orally once daily for 12 weeks (NCT02759315/protocol PN035). The primary efficacy endpoint was sustained virologic response at 12 weeks after the end of therapy (SVR12). One hundred and sixty participants were enrolled. SVR12 rates were 96% (52 of 54) in participants with GT1a infection; 100% (15 of 15) in those with GT1b infection; 97% (28 of 29) in those with GT2 infection; 77% (30 of 39) in those with GT3 infection; 90% (18 of 20) in those with GT4 infection; and 67% (2 of 3) in those with GT6 infection. Drug-related adverse events (AEs) reported by >5% of participants were fatigue (n = 10, 6.3%) and diarrhoea (n = 9, 5.6%). Five participants reported a total of 11 serious AEs, none considered drug-related. One participant experienced on-treatment alanine aminotransferase/aspartate aminotransferase elevations that resolved without intervention. Data from the present study indicate that the combination of RZR 60 mg plus UPR 450 mg once daily for 12 weeks was well tolerated overall but was effective only for certain genotypes.

Efficacy and safety of a two-drug direct-acting antiviral agent regimen ruzasvir 180 mg and uprifosbuvir 450 mg for 12 weeks in adults with chronic hepatitis C virus genotype 1, 2, 3, 4, 5 or 6.

Ruzasvir (MK-8408, an NS5A inhibitor) and uprifosbuvir (MK-3682, a nonstructural protein 5B nucleotide inhibitor) are highly potent direct-acting antiviral agents for the treatment of hepatitis C virus (HCV) infection. A phase III clinical trial evaluating the two-drug combination of ruzasvir 60 mg plus uprifosbuvir 450 mg suggested suboptimal efficacy in certain HCV genotypes (C-BREEZE 1; NCT02759315). The aim of the present study was to evaluate the efficacy and safety of ruzasvir in combination with uprifosbuvir administered at a higher dose than that assessed in the earlier study (C-BREEZE 2: NCT02956629/Merck protocol PN041). Treatment-naïve or interferon (with or without ribavirin)-experienced participants with or without compensated cirrhosis were enrolled. All participants received ruzasvir 180 mg plus uprifosbuvir 450 mg once daily for 12 weeks. The primary objectives were the proportion of participants with HCV RNA <15 lU/mL at 12 weeks after the end of study therapy (SVR12), and safety and tolerability of the study drug. Overall, 282 participants were enrolled. SVR12 (n/N) was 91.3% (42/46) in participants infected with HCV genotype (GT) 1a; GT1b, 96.7% (29/30); GT2, 91.5% (43/47); GT3, 73.8% (45/61); GT4, 98.2% (55/56); GT5, 100.0% (18/18); and GT6, 90.9% (20/22). Adverse events (AEs) were reported by 61.3% of participants; drug-related AEs were reported by 33.3%. The most frequent (≥5% of participants) drug-related AEs in all participants were fatigue (7.8%) and headache (7.4%). In conclusion, the two-drug combination of ruzasvir 180 mg plus uprifosbuvir 450 mg for 12 weeks was highly effective and well tolerated in participants infected with HCV GT1, GT2, GT4, GT5 and GT6, with a lower efficacy in GT3-infected persons.

Pharmacokinetics of elbasvir and grazoprevir in subjects with end-stage renal disease or severe renal impairment.

PURPOSE: To describe the phase 1 and population pharmacokinetic investigations that support dosing recommendations for elbasvir/grazoprevir (EBR/GZR) in hepatitis C virus-infected people with advanced chronic kidney disease. METHODS: This was an open-label, two-part, multiple-dose trial (MK-5172 PN050; NCT01937975) in 24 non-HCV-infected participants with end-stage renal disease (ESRD) or severe renal impairment who received once-daily EBR 50 mg and GZR 100 mg for 10 days. Population pharmacokinetic analyses from the phase 3 C-SURFER study (PN052, NCT02092350) were also conducted. RESULTS: When comparing haemodialysis (HD) and non-HD days in participants with ESRD, geometric mean ratios (GMRs) (90% confidence intervals [CIs]) for EBR and GZR AUC0-24 were 1.14 (1.08-1.21) and 0.97 (0.87-1.09). When comparing ESRD and healthy participants, GMRs (90% CIs) for EBR and GZR AUC0-24 were 0.99 (0.75-1.30) and 0.83 (0.56-1.22) on HD days, and 0.86 (0.65-1.14) and 0.85 (0.58-1.25) on non-HD days. GMRs (90% CIs) for AUC0-24 in participants with severe renal impairment relative to healthy controls were 1.65 (1.09-2.49) for GZR and 1.86 (1.38-2.51) for EBR. In population modelling of data from C-SURFER, absolute geometric means of steady-state EBR AUC0-24 were 2.78 and 3.07 µM*h (HD and non-HD recipients) and GZR AUC0-24 were 1.80 and 2.34 µM*h (HD and non-HD recipients). CONCLUSIONS: EBR/GZR represents an important treatment option for HCV infection in people with severe renal impairment and those with ESRD. No dosage adjustment of EBR/GZR is required in people with any degree of renal impairment, including those receiving dialysis.

Effect of Hepatic Impairment on the Pharmacokinetics of Grazoprevir, a Hepatitis C Virus Protease Inhibitor.

Grazoprevir (GZR) plus elbasvir is an approved treatment for chronic infection with hepatitis C virus (HCV) genotype 1 or 4. HCV infection complications include liver cirrhosis, end-stage liver disease, and hepatocellular carcinoma. The objective of this study was to evaluate the pharmacokinetics and safety of multiple-dose GZR (200, 100, or 50 mg) in non-HCV participants with mild, moderate, or severe hepatic impairment (HI), respectively, and in healthy matched controls (protocol MK-5172_p013; Merck & Co., Inc., Kenilworth, NJ). Participants with mild, moderate, or severe HI and controls (aged 18 to 65 years) matched for race, age, sex, and body mass index were enrolled in a 3-part, open-label, sequential-panel pharmacokinetic study. Participants received oral doses of GZR 200 mg (two 100-mg tablets), 100 mg (one 100-mg tablet), or 50 mg (two 25-mg tablets) once daily for 10 days. A total of 50 participants were enrolled: 8 with mild HI, 9 with moderate HI, 8 with severe HI, and a corresponding number of healthy matched controls for each hepatic cohort. Participants with HI demonstrated higher GZR exposure than healthy matched controls and showed an increase in exposure with increasing HI severity. The steady-state GZR AUC0-24 (area under the concentration-time curve from 0 to 24 h) for participants with mild, moderate, or severe HI was ≈2-, ≈5-, or ≈12-fold higher, respectively, than that for healthy matched controls. GZR was generally well tolerated in participants with HI. No dose adjustment is required for GZR in people with HCV with mild HI. GZR is contraindicated for those with moderate or severe HI (Child-Pugh class B or C), since they may have significantly increased GZR exposures that may lead to an increased risk of transaminase elevation.

No clinically meaningful pharmacokinetic interaction between the hepatitis C virus inhibitors elbasvir and grazoprevir and the oral contraceptives ethinyl estradiol and levonorgestrel.

PURPOSE: Oral contraceptive pills (OCPs) are an important element of hepatitis C virus (HCV) treatment in women of childbearing potential. These studies evaluated the safety and pharmacokinetic interactions between elbasvir (EBR) and grazoprevir (GZR) and ethinyl estradiol/levonorgestrel (EE/LNG). METHODS: Both studies were open-label, single-site, two-period, fixed-sequence, one-way interaction studies. In period 1, subjects received one tablet of EE/LNG (0.03 mg/0.15 mg). In period 2, subjects received EBR (50 mg once daily) for 13 days or GZR (200 mg once daily) for 10 days, with one tablet of EE/LNG on day 7 (GZR group) or 10 (EBR group). Each study enrolled 20 healthy, nonsmoking adult females. RESULTS: There was no clinically meaningful effect of multiple doses of EBR or GZR on the pharmacokinetics of EE or LNG. Geometric mean ratios (GMRs) for AUC0-∞ and Cmax in the presence and absence of EBR were 1.01 and 1.10 for EE and 1.14 and 1.02 for LNG, with 90% confidence intervals (CIs) that were contained in the interval [0.80, 1.25]. Similarly, the AUC0-∞ and Cmax GMRs in the presence and absence of GZR were 1.10 and 1.05 for EE and 1.23 and 0.93 for LNG, respectively. The 90% CIs for EE AUC0-∞ and for EE and LNG Cmax were contained in the interval [0.80, 1.25]; however, the 90% CI for the LNG AUC0-∞ [1.15, 1.32] slightly exceeded the upper bound. CONCLUSIONS: These results suggest that EBR/GZR can be co-administered to female patients with HCV of childbearing potential who are on OCPs to prevent pregnancy.

Susceptibilities of genotype 1a, 1b, and 3 hepatitis C virus variants to the NS5A inhibitor elbasvir.

Elbasvir is an investigational NS5A inhibitor with in vitro activity against multiple HCV genotypes. Antiviral activity of elbasvir was measured in replicons derived from wild-type or resistant variants of genotypes 1a, 1b, and 3. The barrier to resistance was assessed by the number of resistant colonies selected by exposure to various elbasvir concentrations. In a phase 1b dose-escalating study, virologic responses were determined in 48 noncirrhotic adult men with chronic genotype 1 or 3 infections randomized to placebo or elbasvir from 5 to 50 mg (genotype 1) or 10 to 100 mg (genotype 3) once daily for 5 days. The NS5A gene was sequenced from plasma specimens obtained before, during, and after treatment. Elbasvir suppressed the emergence of resistance-associated variants (RAVs) in vitro in a dose-dependent manner. Variants selected by exposure to high elbasvir concentrations typically encoded multiple amino acid substitutions (most commonly involving loci 30, 31, and 93), conferring high-level elbasvir resistance. In the monotherapy study, patients with genotype 1b had greater reductions in HCV RNA levels than patients with genotype 1a at all elbasvir doses; responses in patients with genotype 3 were generally less pronounced than for genotype 1, particularly at lower elbasvir doses. M28T, Q30R, L31V, and Y93H in genotype 1a, L31V and Y93H in genotype 1b, and A30K, L31F, and Y93H in genotype 3 were the predominant RAVs selected by elbasvir monotherapy. Virologic findings in patients were consistent with the preclinical observations. NS5A-RAVs emerged most often at amino acid positions 28, 30, 31, and 93 in both the laboratory and clinical trial. (The MK-8742 P002 trial has been registered at ClinicalTrials.gov under identifier NCT01532973.).

Efficiency of cell-free and cell-associated virus in mucosal transmission of human immunodeficiency virus type 1 and simian immunodeficiency virus.

Effective strategies are needed to block mucosal transmission of human immunodeficiency virus type 1 (HIV-1). Here, we address a crucial question in HIV-1 pathogenesis: whether infected donor mononuclear cells or cell-free virus plays the more important role in initiating mucosal infection by HIV-1. This distinction is critical, as effective strategies for blocking cell-free and cell-associated virus transmission may be different. We describe a novel ex vivo model system that utilizes sealed human colonic mucosa explants and demonstrate in both the ex vivo model and in vivo using the rectal challenge model in rhesus monkeys that HIV-1-infected lymphocytes can transmit infection across the mucosa more efficiently than cell-free virus. These findings may have significant implications for our understanding of the pathogenesis of mucosal transmission of HIV-1 and for the development of strategies to prevent HIV-1 transmission.

Effect of Bamlanivimab as Monotherapy or in Combination with Etesevimab or Sotrovimab on Persistently High Viral Load in Patients with Mild-to-Moderate COVID-19: A Randomized, Phase 2 BLAZE-4 Trial.

INTRODUCTION: Treatment with monoclonal antibodies provides rapid, passive immunity and may stop COVID-19 disease progression. The study evaluated the effect of bamlanivimab (BAM) or BAM + etesevimab (ETE)/sotrovimab compared to placebo on SARS-CoV-2 viral load in patients with COVID-19. METHODS: The phase 2, randomized, single-dose study included patients aged between ≥ 18 and < 65 years, not hospitalized at the time of randomization, and had ≥ 1 mild or moderate COVID-19 symptoms. Study included arms 1-6 (placebo, BAM 175 mg + ETE 350 mg, BAM 700 mg + ETE 1400 mg, BAM 2800 mg + ETE 2800 mg, BAM 700 mg alone, and BAM 350 mg + ETE 700 mg, respectively), BAM 700 mg + ETE 700 mg unintentional dosing; and arms 7 and 8 (BAM 700 mg + sotrovimab 500 mg and placebo, respectively). The primary endpoint was proportion of patients with SARS-CoV-2 log viral load > 5.27 on day 7 (persistently high viral load [PHVL]) who received BAM or BAM + (ETE or sotrovimab). RESULTS: A total of 725 patients, mean age 39.6 years (range 18-75 years), 50.2% male were randomized and infused with study drug in arms 1-6; and a total 202 patients, mean age 38 years (range 18-63 years), 53.5% female were randomized and infused with study drug in arms 7 and 8. A significantly lower proportion of patients in arms 2-6 and arm 7 experienced PHVL on day 7 compared to placebo. On day 7, patients in arms 2, 3, and 6 consistently experienced significantly greater reduction in viral load than placebo. Significant improvement was observed in time to viral load clearance and time to symptom improvement by day 29 in some arms compared to placebo. No new safety concerns were observed with drug combinations. CONCLUSION: The study demonstrated that a significantly lower proportion of patients with mild-to-moderate COVID-19 treated with BAM or BAM + (ETE or sotrovimab) experienced a PHVL at day 7. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT04634409.

Envelope variable region 4 is the first target of neutralizing antibodies in early simian immunodeficiency virus mac251 infection of rhesus monkeys.

A major goal of AIDS vaccine development is to design vaccination strategies that can elicit broad and potent protective antibodies. The initial viral targets of neutralizing antibodies (NAbs) early after human or simian immunodeficiency virus (HIV/SIV) infection are not known. The identification of early NAb epitopes that induce protective immunity or retard the progression of disease is important for AIDS vaccine development. The aim of this study was to determine the Env residues targeted by early SIV NAbs and to assess the influence of prior vaccination on neutralizing antibody kinetics and specificity during early infection. We previously described stereotypic env sequence variations in SIVmac251-infected rhesus monkeys that resulted in viral escape from NAbs. Here, we defined the early viral targets of neutralization and determined whether the ability of serum antibody from infected monkeys to neutralize SIV was altered in the setting of prior vaccination. To localize the viral determinants recognized by early NAbs, a panel of mutant pseudoviruses was assessed in a TZM-bl reporter gene neutralization assay to define the precise changes that eliminate recognition by SIV Env-specific NAbs in 16 rhesus monkeys. Changing R420 to G or R424 to Q in V4 of Env resulted in the loss of recognition by NAbs in vaccinated monkeys. In contrast, mutations in the V1 region of Env did not alter the NAb profile. These findings indicate that early NAbs are directed toward SIVmac251 Env V4 but not the V1 region, and that this env vaccination regimen did not alter the kinetics or the breadth of NAbs during early infection.

Virus inhibition activity of effector memory CD8(+) T cells determines simian immunodeficiency virus load in vaccinated monkeys after vaccine breakthrough infection.

The goal of an effective AIDS vaccine is to generate immunity that will prevent human immunodeficiency virus 1 (HIV-1) acquisition. Despite limited progress toward this goal, renewed optimism has followed the recent success of the RV144 vaccine trial in Thailand. However, the lack of complete protection in this trial suggests that breakthroughs, where infection occurs despite adequate vaccination, will be a reality for many vaccine candidates. We previously reported that neutralizing antibodies elicited by DNA prime-recombinant adenovirus serotype 5 (rAd5) boost vaccination with simian immunodeficiency virus strain mac239 (SIVmac239) Gag-Pol and Env provided protection against pathogenic SIVsmE660 acquisition after repeated mucosal challenge. Here, we report that SIV-specific CD8(+) T cells elicited by that vaccine lowered both peak and set-point viral loads in macaques that became infected despite vaccination. These SIV-specific CD8(+) T cells showed strong virus-inhibitory activity (VIA) and displayed an effector memory (EM) phenotype. VIA correlated with high levels of CD107a mobilization and perforin expression in SIV-specific CD8(+) T cells. Remarkably, both the frequency and the number of Gag CM9-specific public clonotypes were strongly correlated with VIA mediated by EM CD8(+) T cells. The ability to elicit such virus-specific EM CD8(+) T cells might contribute substantially to an efficacious HIV/AIDS vaccine, even after breakthrough infection.

Population pharmacokinetics and exposure-response analysis of a single dose of sotrovimab in the early treatment of patients with mild to moderate COVID-19.

Sotrovimab is a recombinant human monoclonal antibody that has been shown to prevent progression to hospitalization or death in non-hospitalized high-risk patients with mild to moderate coronavirus disease 2019 following either intravenous (i.v.) or intramuscular (i.m.) administration. Population pharmacokinetic (PopPK) and exposure-response (ER) analyses were performed to characterize single dose sotrovimab pharmacokinetics (PK) and the relationship between exposure and response (probability of progression), as well as covariates that may contribute to between-participant variability in sotrovimab PK and efficacy following i.v. or i.m. administration. Sotrovimab PK was described by a two-compartment model with linear elimination; i.m. absorption was characterized by a sigmoid absorption model. PopPK covariate analysis led to the addition of the effect of body weight on systemic clearance and peripheral volume of distribution, sex on i.m. bioavailability and first-order absorption rate (KA), and body mass index on KA. However, the magnitude of covariate effect was not pronounced and was therefore not expected to be clinically relevant based on available data to date. For ER analysis, sotrovimab exposure measures were predicted using the final PopPK model. An ER model was developed using the exposure measure of sotrovimab concentration at 168 h that described the relationship between exposure and probability of progression within the ER dataset for COMET-TAIL. The number of risk factors (≤1 vs. >1) was incorporated as an additive shift on the model-estimated placebo response but had no impact on overall drug response. Limitations in the ER model may prevent generalization of these results to describe the sotrovimab exposure-progression relationship across severe acute respiratory syndrome-coronavirus 2 variants.

Intramuscular vs Intravenous SARS-CoV-2 Neutralizing Antibody Sotrovimab for Treatment of COVID-19 (COMET-TAIL): A Randomized Noninferiority Clinical Trial.

Background: Convenient administration of coronavirus disease 2019 (COVID-19) treatment in community settings is desirable. Sotrovimab is a pan-sarbecovirus dual-action monoclonal antibody formulated for intravenous (IV) or intramuscular (IM) administration for early treatment of mild/moderate COVID-19. Method: This multicenter phase 3 study based on a randomized open-label design tested the noninferiority of IM to IV administration according to an absolute noninferiority margin of 3.5%. From June to August 2021, patients aged ≥12 years with COVID-19, who were neither hospitalized nor receiving supplemental oxygen but were at high risk for progression, were randomized 1:1:1 to receive sotrovimab as a single 500-mg IV infusion or a 500- or 250-mg IM injection. The primary composite endpoint was progression to (1) all-cause hospitalization for >24 hours for acute management of illness or (2) all-cause death through day 29. Results: Sotrovimab 500 mg IM was noninferior to 500 mg IV: 10 (2.7%) of 376 participants vs 5 (1.3%) of 378 met the primary endpoint, respectively (absolute adjusted risk difference, 1.06%; 95% CI, -1.15% to 3.26%). The 95% CI upper limit was lower than the prespecified noninferiority margin of 3.5%. The 250-mg IM group was discontinued early because of the greater proportion of hospitalizations vs the 500-mg groups. Serious adverse events occurred in <1% to 2% of participants across groups. Four participants experienced serious disease-related events and died (500 mg IM, 2/393, <1%; 250 mg IM, 2/195, 1%). Conclusions: Sotrovimab 500-mg IM injection was well tolerated and noninferior to IV administration. IM administration could expand outpatient treatment access for COVID-19. Clinical Trials Registration: ClinicalTrials.gov: NCT04913675.

Epitope-specific CD8+ T lymphocytes cross-recognize mutant simian immunodeficiency virus (SIV) sequences but fail to contain very early evolution and eventual fixation of epitope escape mutations during SIV infection.

Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) evade containment by CD8(+) T lymphocytes through focused epitope mutations. However, because of limitations in the numbers of viral sequences that can be sampled, traditional sequencing technologies have not provided a true representation of the plasticity of these viruses or the intensity of CD8(+) T lymphocyte-mediated selection pressure. Moreover, the strategy by which CD8(+) T lymphocytes contain evolving viral quasispecies has not been characterized fully. In the present study we have employed ultradeep 454 pyrosequencing of virus and simultaneous staining of CD8(+) T lymphocytes with multiple tetramers in the SIV/rhesus monkey model to explore the coevolution of virus and the cellular immune response during primary infection. We demonstrated that cytotoxic T lymphocyte (CTL)-mediated selection pressure on the infecting virus was manifested by epitope mutations as early as 21 days following infection. We also showed that CD8(+) T lymphocytes cross-recognized wild-type and mutant epitopes and that these cross-reactive cell populations were present at a time when mutant forms of virus were present at frequencies of as low as 1 in 22,000 sequenced clones. Surprisingly, these cross-reactive cells became enriched in the epitope-specific CD8(+) T lymphocyte population as viruses with mutant epitope sequences largely replaced those with epitope sequences of the transmitted virus. These studies demonstrate that mutant epitope-specific CD8(+) T lymphocytes that are present at a time when viral mutant epitope sequences are detected at extremely low frequencies fail to contain the later accumulation and fixation of the mutant epitope sequences in the viral quasispecies.

The TRIM5 gene modulates penile mucosal acquisition of simian immunodeficiency virus in rhesus monkeys.

There is considerable variability in host susceptibility to human immunodeficiency virus type 1 (HIV-1) infection, but the host genetic determinants of that variability are not well understood. In addition to serving as a block for cross-species retroviral infection, TRIM5 was recently shown to play a central role in limiting primate immunodeficiency virus replication. We hypothesized that TRIM5 may also contribute to susceptibility to mucosal acquisition of simian immunodeficiency virus (SIV) in rhesus monkeys. We explored this hypothesis by establishing 3 cohorts of Indian-origin rhesus monkeys with different TRIM5 genotypes: homozygous restrictive, heterozygous permissive, and homozygous permissive. We then evaluated the effect of TRIM5 genotype on the penile transmission of SIVsmE660. We observed a significant effect of TRIM5 genotype on mucosal SIVsmE660 acquisition in that no SIV transmission occurred in monkeys with only restrictive TRIM5 alleles. In contrast, systemic SIV infections were initiated after preputial pocket exposures in monkeys that had at least one permissive TRIM5 allele. These data demonstrate that host genetic factors can play a critical role in restricting mucosal transmission of a primate immunodeficiency virus. In addition, we used our understanding of TRIM5 to establish a novel nonhuman primate penile transmission model for AIDS mucosal pathogenesis and vaccine research.

Invasive Mycoleptodiscus fungal cellulitis and myositis.

We report progressive necrotizing fungal cellulitis and myositis in the leg of a patient with glioblastoma multiforme treated with temozolomide and corticosteroids. While the morphologic appearance of the isolate and its ability to grow at temperatures greater than 32°C were suggestive of Mycoleptodiscus indicus, some of the conidia were atypical for this species in that they had single septa and occasional lateral appendages. Furthermore, the isolate was different from M. indicus based on the sequencing analysis of two rDNA regions. This is the first case of Mycoleptodiscus invasive fungal disease in which the causative agent could not be resolved at the species level because of inconsistencies between morphological and molecular data.