520. Pharmacokinetic and Safety Phase 1 Study and Microneutralization Assay Results with BRII-196/BRII-198, a Novel Antibody Cocktail Active Against a Wide Range of SARS-CoV-2 Variants

Abstract Background BRII-196 and BRII-198 are human monoclonal antibodies (mAb) with an extended half-life targeting distinct epitopes of the spike protein on SARS-CoV-2. Mutations in these epitope regions are continuously emerging, potentially conferring resistance to COVID-19 therapeutics in development. Individual phase I studies showed that BRII-196 or BRII-198 alone were safe and well tolerated in healthy subjects. The BRII-196 and BRII-198 cocktail is currently under evaluation in Phase 2/3 studies for the treatment of COVID-19. Methods Preclinical study: BRII-196 and BRII-198 were evaluated in the microneutralization assay using pseudo-viruses encoding mutations identified in the spike protein of a panel of SARS-CoV-2 variants of concerns, including strains originating in UK, SA, BR, CA, and India. The fold-change in neutralization IC50 titers relative to wild-type virus was calculated. Phase 1 study: healthy adults received sequential IV BRII-196 and BRII-198 (n=9) or placebo (n=3); and were followed for 180 days. Two dose levels (750mg/750mg and 1500mg/1500mg) were evaluated for safety, pharmacokinetics and immunogenicity. Interim analysis results are presented. Results Preclinical: BRII-196 and BRII-198 exhibited neutralizing activity against pseudo-virus variants that contained spike mutations of a panel of variants including B.1.1.7 (UK), B.1.351(SA), P.1(BR), B.1.427/429 (CA), B.1.526 (NY), and B.1.617 (IN), comparable to that against wild-type virus. Phase I study: BRII-196 plus BRII-198 was well tolerated with no dose-limiting adverse events (AEs), deaths, serious adverse events, or infusion reactions. The majority of AEs were isolated asymptomatic grade 1-2 laboratory abnormalities. (Table 1). Each mAb displayed pharmacokinetic characteristics expected of extended half-life YTE-antibodies. Conclusion The BRII-196 and BRII-198 cocktail was well-tolerated, and maintains neutralization against currently reported circulating variants of concern. These preclinical and clinical results support further development of BRII-196 and BRII-198 as a therapeutic or prophylactic option for SARS-CoV-2. Disclosures David A. Margolis, MD MPH, Brii Biosciences (Employee) Yao Zhang, MD, Brii Biosciences (Employee) Yun Ji, PhD, Brii Biosciences (Employee, Shareholder)

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Different dose regimens of a SARS-CoV-2 recombinant spike protein vaccine (NVX-CoV2373) in younger and older adults: A phase 2 randomized placebo-controlled trial

PLoS Medicine ◽

10.1371/journal.pmed.1003769 ◽

2021 ◽

Vol 18 (10) ◽

pp. e1003769

Author(s):

Neil Formica ◽

Raburn Mallory ◽

Gary Albert ◽

Michelle Robinson ◽

Joyce S. Plested ◽

...

Keyword(s):

Dose Regimen ◽

Phase 1 ◽

Late Phase ◽

Age Groups ◽

Neutralizing Antibody ◽

Spike Protein ◽

Wild Type Virus ◽

Phase 2 ◽

Type Virus ◽

Wild Type

Background NVX-CoV2373 is a recombinant severe acute respiratory coronavirus 2 (rSARS-CoV-2) nanoparticle vaccine composed of trimeric full-length SARS-CoV-2 spike glycoproteins and Matrix-M1 adjuvant. Methods and findings The phase 2 component of our randomized, placebo-controlled, phase 1 to 2 trial was designed to identify which dosing regimen of NVX-CoV2373 should move forward into late-phase studies and was based on immunogenicity and safety data through Day 35 (14 days after the second dose). The trial was conducted at 9 sites in Australia and 8 sites in the United States. Participants in 2 age groups (aged 18 to 59 and 60 to 84 years) were randomly assigned to receive either 1 or 2 intramuscular doses of 5-μg or 25-μg NVX-CoV2373 or placebo, 21 days apart. Primary endpoints were immunoglobulin G (IgG) anti-spike protein response, 7-day solicited reactogenicity, and unsolicited adverse events. A key secondary endpoint was wild-type virus neutralizing antibody response. After enrollment, 1,288 participants were randomly assigned to 1 of 4 vaccine groups or placebo, with 1,283 participants administered at least 1 study treatment. Of these, 45% were older participants 60 to 84 years. Reactogenicity was predominantly mild to moderate in severity and of short duration (median <3 days) after first and second vaccination with NVX-CoV2373, with higher frequencies and intensity after second vaccination and with the higher dose. Reactogenicity occurred less frequently and was of lower intensity in older participants. Both 2-dose regimens of 5-μg and 25-μg NVX-CoV2373 induced robust immune responses in younger and older participants. For the 2-dose regimen of 5 μg, geometric mean titers (GMTs) for IgG anti-spike protein were 65,019 (95% confidence interval (CI) 55,485 to 76,192) and 28,137 (95% CI 21,617 to 36,623) EU/mL and for wild-type virus neutralizing antibody (with an inhibitory concentration of 50%—MN50%) were 2,201 (95% CI 1,343 to 3,608) and 981 (95% CI 560 to 1,717) titers for younger and older participants, respectively, with seroconversion rates of 100% in both age groups. Neutralizing antibody responses exceeded those seen in a panel of convalescent sera for both age groups. Study limitations include the relatively short duration of safety follow-up to date and current lack of immune persistence data beyond the primary vaccination regimen time point assessments, but these data will accumulate over time. Conclusions The study confirmed the phase 1 findings that the 2-dose regimen of 5-μg NVX-CoV2373 is highly immunogenic and well tolerated in younger adults. In addition, in older adults, the 2-dose regimen of 5 μg was also well tolerated and showed sufficient immunogenicity to support its use in late-phase efficacy studies. Trial registration ClinicalTrials.gov NCT04368988.

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Evaluation of a SARS-CoV-2 Vaccine NVX-CoV2373 in Younger and Older Adults

10.1101/2021.02.26.21252482 ◽

2021 ◽

Author(s):

Neil Formica ◽

Raburn Mallory ◽

Gary Albert ◽

Michelle Robinson ◽

Joyce Plested ◽

...

Keyword(s):

Dose Regimen ◽

Phase 1 ◽

Geometric Mean ◽

Age Groups ◽

Safety Data ◽

Neutralizing Antibody ◽

Spike Protein ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type

Background NVX CoV2373 is a recombinant severe acute respiratory coronavirus 2 (rSARS-CoV-2) nanoparticle vaccine composed of trimeric full-length SARS CoV-2 spike glycoproteins and Matrix-M1 adjuvant. Methods The phase 2 component of our randomized, placebo-controlled, phase 1-2 trial was designed to identify which dosing regimen of NVX-CoV2373 should move forward into late phase studies in younger (18-59 years) and older (60-84 years) participants and was based on immunogenicity and safety data through day 35 (14 days after the second dose). Participants were randomly assigned to receive either one or two intramuscular doses of 5-microgram or 25-microgram NVX-CoV2373 or placebo, 21 days apart. Primary endpoints were immunoglobulin G (IgG) anti-spike protein response, 7 day solicited reactogenicity, and unsolicited adverse events. A key secondary endpoint was wild type virus neutralizing antibody response. Results After randomization, approximately 250 participants each were assigned to one of four vaccine groups or placebo. Of these, approximately 45% were older participants. Reactogenicity was predominantly mild to moderate in severity and of short duration (median <3 days) after first and second vaccination with NVX-CoV2373, with higher frequencies and intensity after second vaccination and with the higher dose, and occurred less frequently and was of lower intensity in older participants. The two-dose regimen of 5-microgram NVX-CoV2373 induced robust geometric mean titer (GMT) IgG anti-spike protein (65,019 and 28,137 EU/mL) and wild-type virus neutralizing antibody (2201 and 981 titers) responses in younger and older participants, respectively, with seroconversion rates of 100% in both age groups. Neutralizing antibody responses exceeded those seen in convalescent sera for both age groups. Conclusions The study confirmed that the two-dose regimen of 5 microgram NVX CoV2373 is highly immunogenic and well tolerated in both younger and older participants. (Funded by the Coalition for Epidemic Preparedness Innovations; ClinicalTrials.gov number: NCT04368988).

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Ultrapotent bispecific antibodies neutralize emerging SARS-CoV-2 variants

10.1101/2021.04.01.437942 ◽

2021 ◽

Author(s):

Hyeseon Cho ◽

Kristina Kay Gonzales-Wartz ◽

Deli Huang ◽

Meng Yuan ◽

Mary Peterson ◽

...

Keyword(s):

Bispecific Antibody ◽

Complete Loss ◽

Memory B Cells ◽

Spike Protein ◽

Bispecific Antibodies ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Hamster Model

The emergence of SARS-CoV-2 variants that threaten the efficacy of existing vaccines and therapeutic antibodies underscores the urgent need for new antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells of COVID-19 patients. The three most potent antibodies targeted distinct regions of the RBD, and all three neutralized the SARS-CoV-2 variants B.1.1.7 and B.1.351. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the ACE2 receptor, and has limited contact with key variant residues K417, E484 and N501. We designed bispecific antibodies by combining non-overlapping specificities and identified five ultrapotent bispecific antibodies that inhibit authentic SARS-CoV-2 infection at concentrations of <1 ng/mL. Through a novel mode of action three bispecific antibodies cross-linked adjacent spike proteins using dual NTD/RBD specificities. One bispecific antibody was >100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a 2.5 mg/kg dose. Notably, six of nine bispecific antibodies neutralized B.1.1.7, B.1.351 and the wild-type virus with comparable potency, despite partial or complete loss of activity of at least one parent monoclonal antibody against B.1.351. Furthermore, a bispecific antibody that neutralized B.1.351 protected against SARS-CoV-2 expressing the crucial E484K mutation in the hamster model. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.

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Age-Dependent Reduction in Neutralization against Alpha and Beta Variants of BNT162b2 SARS-CoV-2 Vaccine-Induced Immunity

Microbiology Spectrum ◽

10.1128/spectrum.00561-21 ◽

2021 ◽

Author(s):

Hitoshi Kawasuji ◽

Yoshitomo Morinaga ◽

Hideki Tani ◽

Yumiko Saga ◽

Makito Kaneda ◽

...

Keyword(s):

Age Groups ◽

Older Age ◽

Spike Protein ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Neutralizing Activity ◽

Age Dependent ◽

Induced Immunity

Since mRNA vaccines utilize wild-type SARS-CoV-2 spike protein as an antigen, there are potential concerns about acquiring immunity to variants of this virus. The neutralizing activity in BNT162b2-vaccinated individuals was higher against the wild-type virus than against its variants; this effect was more apparent in older age groups.

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Pharmacokinetics of Darunavir at 900 Milligrams and Ritonavir at 100 Milligrams Once Daily when Coadministered with Efavirenz at 600 Milligrams Once Daily in Healthy Volunteers

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01564-09 ◽

2010 ◽

Vol 54 (7) ◽

pp. 2775-2780 ◽

Cited By ~ 6

Author(s):

Gaik H. Soon ◽

Ping Shen ◽

Eu-Leong Yong ◽

Paul Pham ◽

Charles Flexner ◽

...

Keyword(s):

Healthy Volunteers ◽

Half Life ◽

Geometric Mean ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Time Curve ◽

Once Daily ◽

Drug Concentrations ◽

Trough Concentrations

ABSTRACT Ritonavir-boosted darunavir with efavirenz may be considered a nucleoside-sparing regimen for treatment-naïve HIV-infected patients. However, the pharmacokinetics of this combination administered once daily have not been studied. We conducted a three-period interaction study with healthy volunteers. The subjects were given darunavir at 900 mg with ritonavir at 100 mg once daily for 10 days. Efavirenz at 600 mg once daily was added for 14 days. Darunavir-ritonavir was then stopped and efavirenz alone was given for 14 days. At the end of each period, blood was taken predosing and for up to 24 h postdosing to measure the drug concentrations. We recruited seven males and five females ages 24 to 49 years and weighing 50 to 83 kg. The darunavir trough concentrations were reduced after efavirenz administration (geometric mean ratio [GMR], 0.43; 90% confidence interval [CI], 0.32 to 0.57]; P < 0.001). The mean darunavir trough concentrations were 1,180 ng/ml (standard deviation, 1,138 ng/ml) after efavirenz administration, but all darunavir trough concentrations were above the 50% effective concentration (EC50) of 55 ng/ml for the wild-type virus. For darunavir, the area under the concentration-time curve from 0 to 24 h (AUC0-24) (GMR, 0.86; 90% CI, 0.75 to 0.97; P = 0.05) and the half-life (GMR, 0.56; 90% CI, 0.49 to 0.65; P < 0.001) were also significantly reduced. The darunavir peak concentrations were not significantly changed (GMR, 0.92; 90% CI, 0.82 to 1.03; P = 0.23). The ritonavir trough concentrations (GMR, 0.46; 90% CI, 0.33 to 0.63; P = 0.001), AUC0-24 (GMR, 0.74; 90% CI, 0.64 to 0.86; P = 0.004), and half-life (GMR, 0.80; 90% CI, 0.75 to 0.86; P < 0.001) were also significantly reduced. The efavirenz half-life was significantly longer when it was coadministered with darunavir-ritonavir than when it was given alone (GMR, 1.66; 90% CI, 1.24 to 2.23; P = 0.01), but there were no differences in the efavirenz trough or peak concentration or AUC0-24 when it was coadministered with darunavir-ritonavir. Efavirenz reduced the trough concentrations of darunavir significantly, but the concentrations remained above the EC50 for the wild-type virus. This regimen should be evaluated with treatment-naïve patients with no preexisting resistance.

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D614G Substitution of SARS-CoV-2 Spike Protein Increases Syncytium Formation and Virus Titer via Enhanced Furin-Mediated Spike Cleavage

mBio ◽

10.1128/mbio.00587-21 ◽

2021 ◽

Author(s):

Ya-Wen Cheng ◽

Tai-Ling Chao ◽

Chiao-Ling Li ◽

Sheng-Han Wang ◽

Han-Chieh Kao ◽

...

Keyword(s):

Virus Titer ◽

Syncytium Formation ◽

Selective Advantage ◽

Spike Protein ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Evolutionary Trajectory ◽

Viral Genomes ◽

Over Time

Analysis of viral genomes and monitoring of the evolutionary trajectory of SARS-CoV-2 over time has identified the D614G substitution in spike (S) as the most prevalent expanding variant worldwide, which might confer a selective advantage in transmission. Several studies showed that the D614G variant replicates and transmits more efficiently than the wild-type virus, but the mechanism is unclear.

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Pathogenicity, immunogenicity, and protective ability of an attenuated SARS-CoV-2 variant with a deletion at the S1/S2 junction of the spike protein

10.1101/2020.08.24.264192 ◽

2020 ◽

Author(s):

Pui Wang ◽

Siu-Ying Lau ◽

Shaofeng Deng ◽

Pin Chen ◽

Bobo Wing-Yee Mok ◽

...

Keyword(s):

Antibody Response ◽

Proinflammatory Cytokines ◽

Neutralizing Antibody ◽

Spike Protein ◽

Parental Virus ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Cleavage Motif ◽

Sterilizing Immunity

AbstractSARS-CoV-2 contains a PRRA polybasic cleavage motif considered critical for efficient infection and transmission in humans. We previously reported that virus variants with spike protein S1/S2 junction deletions spanning this motif are attenuated. Here we characterize a further cell-adapted SARS-CoV-2 variant, Ca-DelMut. Ca-DelMut replicates more efficiently than wild type or parental virus in cells, but causes no apparent disease in hamsters, despite replicating in respiratory tissues. Unlike wild type virus, Ca-DelMut does not induce proinflammatory cytokines in hamster infections, but still triggers a strong neutralizing antibody response. Ca-DelMut-immunized hamsters challenged with wild type SARS-CoV-2 are fully protected, demonstrating sterilizing immunity.

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Pharmacokinetics of Once-Daily Darunavir-Ritonavir and Atazanavir-Ritonavir over 72 Hours following Drug Cessation

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01747-10 ◽

2011 ◽

Vol 55 (9) ◽

pp. 4218-4223 ◽

Cited By ~ 27

Author(s):

Marta Boffito ◽

Akil Jackson ◽

Alieu Amara ◽

David Back ◽

Saye Khoo ◽

...

Keyword(s):

Protein Binding ◽

Half Life ◽

Wild Type Virus ◽

Pharmacokinetic Parameters ◽

Type Virus ◽

Wild Type ◽

Minimum Effective Concentration ◽

Once Daily ◽

Elimination Half Life ◽

Elimination Half

ABSTRACTThe object of this study was to investigate the pharmacokinetics of darunavir-ritonavir and atazanavir-ritonavir once-daily dosing over 72 h (h) following drug intake cessation. Volunteers received darunavir-ritonavir at 800 and 100 mg, respectively, once daily for 10 days, followed by a 7-day washout period, and atazanavir-ritonavir at 300 and 100 mg, respectively, once daily for 10 days. Full pharmacokinetic profiles were assessed for each phase for the 72 h following day 10. Pharmacokinetic parameters were determined over 24 h and to the last measurable concentration by noncompartmental methods. Seventeen subjects completed the study. The geometric mean (GM) terminal elimination half-life to 72 h of darunavir was 6.48 h, which was lower than the 0- to 24-h half-life (10.70 h). The terminal elimination half-life of atazanavir was 6.74 h, which was lower than the 0- to 24-h half-life (13.72 h). All subjects but one had darunavir concentrations higher than the target of 550 ng/ml for protease-resistant HIV isolates (equivalent to 10 times the protein-binding-corrected 50% inhibitory concentration [IC50] for wild-type virus) at 24 h postdose, and 14 out of 17 had concentrations higher than the target at 30 h postdose (GM of 1,088 and 851 ng/ml). All subjects had atazanavir concentrations above the suggested minimum effective concentration of 150 ng/ml (equivalent to 10 times the protein-binding-corrected IC50for wild-type virus) at 24 and 30 h postdose (GM of 693 and 392 ng/ml). Two of 17 and 5 of 17 subjects were above target at 48 h postdose while on darunavir-ritonavir and atazanavir-ritonavir. Ritonavir half-life to 72 h was 6.84 h with darunavir and 6.07 with atazanavir. This study investigated the pharmacokinetic forgiveness of two boosted protease inhibitors. Although the rates of decline of darunavir and atazanavir slightly increased as ritonavir concentrations declined, most individuals had concentrations 6 h after the end of the ideal dosing interval of 24 h which were above the cutoff used to define therapeutic concentrations.

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