Randomized Trial of Food Effect on Pharmacokinetic Parameters of ABX464 Administered Orally to Healthy Male Subjects.

ABX464 is an antiviral that provides a novel approach to the reduction and control of HIV infection. Investigation of food influence is important in the optimization of treatment. An open-label, food effect, randomized study which included 2 groups of 24 subjects each was carried out to assess the bioavailability and safety of single (group 1) and repeated (group 2) oral doses of ABX464 (50 mg) under fed or fasted conditions. The maximum concentration (Cmax) and the area under the concentration-time curve from time zero to infinity (AUC0-∞) of ABX464 were demonstrated to increase with food after a single dose of ABX464 (219% and 188%, respectively). The apparent terminal elimination half-lives (t1/2s) under fed and fasted conditions were comparable, at about 0.80 h. The median time to maximum concentration (Tmax) was delayed from 1.5 to 2.8 h, and the ratio of the AUC0-∞ obtained under fed conditions to the AUC0-∞ obtained under fasted conditions (Frel) was 2.69. Comparable results were obtained on day 1 and day 10 in group 2. The increases in Cmax and AUC0-∞ of the metabolite ABX464-N-glucuronide (ABX464-NGlc) were, however, much more limited when ABX464 was given with food. The t1/2s were also comparable under the two conditions (around 100 h). Between day 1 and day 10, the Cmax increased by 5% under the fasted condition and by 25% under the fed condition. The most common related treatment-emergent adverse events were headaches, vomiting, and nausea. It was concluded that food has a significant impact on the levels of ABX464 in plasma with a delay in absorption and increased relative bioavailability, with a lesser impact on its biotransformation into ABX464-NGlc. ABX464 was well tolerated under both fasted and fed conditions. (This study has been registered at ClinicalTrials.gov under registration no. NCT02731885.).

Pharmacokinetics and tolerability of ABX464, a novel first-in-class compound to treat HIV infection, in healthy HIV-uninfected subjects.

Background: An anti-HIV compound (ABX464) has been developed with a novel mechanism of activity in that it blocks viral gene expression in cells that are already infected. Objectives: A first-in-man study was conducted to determine the pharmacokinetic and safety profiles of ABX464. This was carried out as an open label, parallel group, single ascending dose, exploratory study. Methods: Twenty-four male subjects in good health without HIV infection, aged from 18 to 55 years old, with BMIs of 18-27 kg/m 2 were included. A single oral dose of ABX464 (50, 100, 150 or 200 mg) was administered on the morning of day 0 after overnight fasting, with follow-up for 45 days. Safety assessments consisted of vital signs, electrocardiogram, physical examination, laboratory tests and urinalysis. Pharmacokinetic parameters were calculated for ABX464 and its main metabolite ABX-464- N -glucuronide (ABX464-NGlc). The study was registered at https://www.clinicaltrials (trial number NCT02792686). Results: ABX464 was well tolerated; the most frequent related treatment-emergent adverse events were headaches, nausea and vomiting; they were not considered as treatment-limiting effects. ABX464's C max was observed approximately 2 h after administration in all groups. ABX464 was rapidly and substantially metabolized into ABX464-NGlc. The C max of ABX464-NGlc was observed approximately 4 h post-dose and was about 160-fold higher than that of the parent with a much longer t 1/2 (90-110 h). The ratio of metabolite to parent drug was consistent across the complete dose range. Conclusions: These studies confirmed that ABX464 is well tolerated and rapidly and substantially metabolized into ABX464-NGlc in human subjects.

Safety and immunogenicity of a vero cell culture-derived whole-virus influenza A(H5N1) vaccine in a pediatric population.

BACKGROUND: Children are highly vulnerable to infection with novel influenza viruses. It is essential to develop candidate pandemic influenza vaccines that are safe and effective in the pediatric population. METHODS: Infants and children aged 6-35 months and 3-8 years, respectively, were randomized to receive 2 immunizations with a 7.5-µg or 3.75-µg hemagglutinin (HA) dose of a nonadjuvanted whole-virus A/Vietnam(H5N1) vaccine; adolescents aged 9-17 years received a 7.5-µg dose only. A subset of participants received a booster immunization with an A/Indonesia(H5N1) vaccine approximately 1 year later. HA and neuraminidase antibody responses were assessed. RESULTS: Vaccination was safe and well tolerated; adverse reactions were transient and predominantly mild. Two immunizations with the 7.5-µg dose of A/Vietnam vaccine induced virus microneutralization (MN) titers of ≥1:20 against the A/Vietnam strain in 68.8%-85.4% of participants in the different age groups. After the booster, 93.1%-100% of participants achieved MN titers of ≥1:20 against the A/Vietnam and A/Indonesia strains. Neuraminidase-inhibiting antibodies were induced in ≥90% of participants after 2 immunizations with the 7.5 µg A/Vietnam vaccine and in 100% of participants after the booster. CONCLUSIONS: A whole-virus influenza A(H5N1) vaccine is suitable for prepandemic or pandemic immunization in a pediatric population. CLINICAL TRIALS REGISTRATION: NCT01052402.

Hyperimmune intravenous immunoglobulin containing high titers of pandemic H1N1 hemagglutinin and neuraminidase antibodies provides dose-dependent protection against lethal virus challenge in SCID mice.

BACKGROUND: Convalescent plasma and fractionated immunoglobulins have been suggested as prophylactic or therapeutic interventions during an influenza pandemic. FINDINGS: Intravenous immunoglobulin (IVIG) preparations manufactured from human plasma collected before the 2009 H1N1 influenza pandemic, and post-pandemic hyperimmune (H)-IVIG preparations were characterized with respect to hemagglutination inhibition (HI), microneutralization (MN) and neuraminidase-inhibiting (NAi) antibody titers against pandemic H1N1 (pH1N1) and seasonal H1N1 (sH1N1) viruses. The protective efficacy of the IVIG and H-IVIG preparations was evaluated in a SCID mouse challenge model.Substantial levels of HI, MN and NAi antibodies against pH1N1 (GMTs 1:45, 1:204 and 1: 727, respectively) and sH1N1 (GMTs 1:688, 1:4,946 and 1:312, respectively) were present in pre-pandemic IVIG preparations. In post-pandemic H-IVIG preparations, HI, MN and NAi antibody GMTs against pH1N1 were 1:1,280, 1:11,404 and 1:2,488 (28-, 56- and 3.4-fold enriched), respectively, compared to pre-pandemic IVIG preparations (p < 0.001). Post-pandemic H-IVIG (HI titer 1:1,280) provided complete protection from lethality of SCID mice against pH1N1 challenge (100% of mice survived for 29 days post-challenge). Pre-pandemic IVIG (HI titer 1:70) did not provide significant protection against pH1N1 challenge (50% of mice survived 29 days post-challenge compared to 40% survival in the buffer control group). There was a highly significant correlation between circulating in vivo HI and MN antibody titers and survival (p < 0001). CONCLUSION: The substantial enrichment of HA- and NA-specific antibodies in H-IVIG and the efficacious protection of SCID mice against challenge with pH1N1 suggests H-IVIG as a promising intervention against pandemic influenza for immunocompromised patients and other risk groups.

A vero cell-derived whole-virus H5N1 vaccine effectively induces neuraminidase-inhibiting antibodies.

A Vero cell-derived whole-virus H5N1 influenza vaccine has been shown to induce neutralizing antibodies directed against the hemagglutinin (HA) protein of diverse H5N1 strains in animal studies and clinical trials. However, neuraminidase-inhibiting (NAi) antibodies can reduce viral spread and may be of particular importance in the event of an H5N1 pandemic, where immunity due to HA antibodies is likely absent in the general population. Here we demonstrate the effective induction of NAi antibody titers after H5N1 vaccination in humans. In contrast to the immune response directed toward HA, a single vaccine dose induced a strong NAi response that was not significantly boosted by a second dose, most probably due to priming by previous vaccination or infection with seasonal influenza viruses. After 2 immunizations, seroconversion rates based on antibody titers against HA and NA were similar, indicating the induction of equally strong immune responses against both proteins by this H5N1 vaccine.

ABX464 (obefazimod) for patients with COVID-19 at risk for severe disease: miR-AGE, a randomized, double-blind placebo-controlled trial.

Background: ABX464 (obefazimod) is a small molecule that upregulates a single microRNA (miR-124) in immune cells and reduces the production of various inflammatory cytokines and chemokines. Objective: We assessed the efficacy and safety of the standard of care (SoC) plus oral obefazimod (SoC plus ABX464), 50 mg once daily, versus the SoC plus placebo for prevention of severe acute respiratory syndrome in patients with coronavirus disease 2019 (COVID-19) who are at risk for severe disease. Methods: Eligible patients for this phase 2/3 double-blind, placebo-controlled miR-AGE study were randomized (2:1) into 2 groups: SoC-ABX464 (n = 339) and SoC-placebo (n = 170). The primary end point was the percentage of patients who did not require use of high-flow oxygen or invasive or noninvasive mechanical ventilation within 28 days. The safety analyses included patients who had been randomly assigned and had received at least 1 dose of the study treatment. Results: At the time of the interim analysis, obefazimod showed no benefit over placebo when added to the SoC; the study enrollment was stopped for futility. The evaluation of the safety of obefazimod in 505 patients showed significantly more treatment-emergent adverse events in the SoC-ABX464 group than in the SoC-placebo group (P = .007). Frequently reported AEs in the SoC-ABX464 group included headache (14.6%), abdominal pain (9.6%), diarrhea (9.0%), back pain (6.9%), and nausea (6.0%). No treatment-related changes in laboratory parameters were reported. Conclusion: For patients who have severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and are at risk for severe COVID-19, obefazimod, 50 mg, provided no benefit over placebo when added to the SoC, although it did have a good safety profile (comparable to that reported in many therapeutic areas).

A cell culture-derived influenza vaccine provides consistent protection against infection and reduces the duration and severity of disease in infected individuals.

BACKGROUND: Current knowledge of the consistency of protection induced by seasonal influenza vaccines over the duration of a full influenza season is limited, and little is known about the clinical course of disease in individuals who become infected despite vaccination. METHODS: Data from a randomized double-blind placebo-controlled clinical trial undertaken in healthy young adults in the 2008-2009 influenza season were used to investigate the weekly cumulative efficacy of a Vero cell culture-derived influenza vaccine. In addition, the duration and severity of disease in vaccine and placebo recipients with cell culture-confirmed influenza infection were compared. RESULTS: Vaccine efficacy against matching strains was consistently high (73%-82%) throughout the study, including the entire period of the influenza season during which influenza activity was above the epidemic threshold. Vaccine efficacy was also consistent (68%-83%) when calculated for all strains, irrespective of antigenic match. Vaccination also ameliorated disease symptoms when infection was not prevented. Bivariate analysis of duration and severity showed a significant amelioration of myalgia (P = .003), headache (P = .025), and fatigue (P = .013) in infected vaccinated subjects compared with placebo. Cough (P = .143) and oropharyngeal pain (P = .083) were also reduced in infected vaccinated subjects. CONCLUSIONS: A Vero cell culture-derived influenza vaccine provides consistently high levels of protection against cell culture-confirmed infection by seasonal influenza virus and significantly reduces the duration and severity of disease in those individuals in which infection is not prevented. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov NCT00566345.

Efficacy, safety, and immunogenicity of a Vero-cell-culture-derived trivalent influenza vaccine: a multicentre, double-blind, randomised, placebo-controlled trial.

BACKGROUND: The use of cell-culture technologies for the manufacture of influenza vaccines might contribute to improved strain selection and robust vaccine supplies. We investigated the safety, immunogenicity, and protective efficacy of a Vero-cell-culture-derived influenza vaccine, and assessed the correlation between vaccine efficacy and haemagglutination inhibition antibody titre. METHODS: In a double-blind, placebo-controlled, phase 3 trial undertaken in 36 centres in the USA, healthy adults (aged 18-49 years) were randomly assigned in a 1:1 ratio to one injection of either placebo or Vero-cell-culture-derived influenza vaccine during the 2008-09 season. Randomisation was done in blocks by use of the random number generator algorithm, and participants were allocated by use of a centralised telephone system. The primary objective was the efficacy of the vaccine in preventing cell-culture-confirmed influenza infection with viruses that were antigenically matched to one of the vaccine strains. Analysis was by intention to treat. The study is registered with ClinicalTrials.gov, number NCT00566345. FINDINGS: 7250 participants were randomly assigned to vaccine (n=3626) and placebo (n=3624). 7236 were analysed for the primary outcome (n=3619 and n=3617, respectively). Overall protective efficacy for antigenically matched influenza infection was 78·5% (95% CI 60·8-88·2). The vaccine was well tolerated with no treatment-related serious adverse events. Adverse events were mainly mild and transient. An HI titre of at least 1:15 provided a reliable correlate of cell-culture-derived influenza vaccine-induced protection; no additional benefit was noted with titres greater than 1:30. INTERPRETATION: The data indicate that existing correlates of protection afforded with egg-derived seasonal influenza vaccines also apply to this vaccine. FUNDING: Federal (US Government) funds from the Office for Preparedness and Response, Biomedical Advanced Research and Development Authority, under contract to DynPort Vaccine Company.

Preparation of commercial quantities of a hyperimmune human intravenous immunoglobulin preparation against an emerging infectious disease: the example of pandemic H1N1 influenza.

BACKGROUND: The recent H1N1 pandemic provided an opportunity to conceptually assess the possibility of rapidly providing a "hyperimmune" human immunoglobulin (H-IVIG) to an emerging infectious disease, in useful quantities with respect to public health. Commercial-scale H-IVIG production from plasma collected from donors convalescent from or vaccinated against pandemic influenza A (H1N1) virus is described. STUDY DESIGN AND METHODS: A special protocol was implemented for the collection, processing, and shipment of plasma from previously qualified source plasma donors, self-identifying as convalescent from or vaccinated against H1N1 influenza. A licensed IVIG manufacturing process was utilized for the preparation of two commercial lots of approximately 50 kg 10% human IVIG preparation in total. The H1N1 hemagglutination inhibition and neutralization antibody titers of the resulting H-IVIG preparations were determined and compared with standard preparations. RESULTS: Twenty-six plasma collection centers participated in the protocol. Donor enrollment exceeded 300 donors per week and within 30 days of protocol deployment plasma was being collected at a rate of more than 2000 L/week. Manufacture of both H-IVIG lots was unremarkable and both lots met the requirements for commercial release and the bulk of the product was distributed in normal commercial channels. Examination of plasma pools and final IVIG product confirmed pandemic H1N1 antibody titers substantially higher than those collected before the emergence of the pandemic H1N1 virus. CONCLUSIONS: This work demonstrates the feasibility of producing a H-IVIG preparation at large scale relatively rapidly, with a significant enrichment in antibodies to the H1N1 influenza, achieved by donor self-identification.

A tick-borne encephalitis virus vaccine based on the European prototype strain induces broadly reactive cross-neutralizing antibodies in humans.

After vaccination of humans with tick-borne encephalitis virus (TBEV) vaccine, the extent of cross-neutralization between viruses of the European, Far Eastern, and Siberian subtypes of TBEV and Omsk hemorrhagic fever virus (OHFV) was analyzed. Hybrid viruses that encode the TBEV surface proteins for representative viruses within all subtypes, and OHFV, were constructed using the West Nile virus (WNV) backbone as vector. These viruses allow for unbiased head-to-head comparison in neutralization assays because they exhibit the antigenic characteristics of the TBEV strains from which the surface proteins were derived and showed equivalent biologic properties in cell culture. Human serum samples derived from a TBEV vaccine trial were analyzed and revealed comparable neutralizing antibody titers against European, Far Eastern, and Siberian subtype viruses, indicating equally potent cross-protection against these TBEV strains and a somewhat reduced but still protective neutralization capacity against more distantly related viruses, such as OHFV.

Demonstration of the Antitumor Activity of the iNKT Agonist ABX196, a Novel Enhancer of Cancer Immunotherapy, in Melanoma and Hepatocarcinoma Mouse Models.

Immune checkpoint blockers (ICB) provide a promising approach to antitumor immunotherapy through blockade of immunosuppressive pathways. The synthetic glycolipid, ABX196, is a potent stimulator of invariant natural killer T cells (iNKT), a small subset of regulatory lymphocytes, which are powerful enhancers of immunity when activated. ABX196 was investigated alone and in combination with chemotherapy and ICBs in a melanoma B16F10 tumor cell-bearing and an orthotopic Hepa 1-6 hepatocarcinoma (HCC) cell-bearing C57BL/6 mice model. In the melanoma model, immune response evaluation included immunofluorescence staining and detection by flow cytometry to identify anti-CD45, anti-CD8, anti-CD4, anti-CD3, anti-CD19, anti-FoxP3, CD1d tetramer, and anti-programmed cell death protein 1 (PD-1) markers. Analysis by MRI, liver weight, and IHC staining to detect CD4, CD8, F4/80, PD-1, programmed death-ligand 1, Ki67, and FoxP3 markers were used to measure antitumor response in the HCC model. Combination treatment with ABX196 and anti-PD-1 resulted in significant synergistic antitumor effects, reflected by the increase of CD8+ cells in the tumor and an increased ratio of CD8+ effector cells to FoxP3+ regulatory T cells (Treg) in mice with melanomas. ABX196 monotherapy and combination therapy resulted in antitumor effects in the HCC model. No significant differences in survival were demonstrated between monotherapy and combination therapy due to high response levels with either treatment. A synergistic combination effect was apparent when IFNγ was measured in peripheral blood, indicating sustained activation of iNKT cells. In both models, the antitumor effects were associated with a generation of a more advantageous T-effector to Treg cell ratio within the tumor, which could lead to in the proliferation and accumulation of cells that would otherwise be anergized. SYNOPSIS: Using melanoma and HCC tumor models in mice, this study demonstrates the potential of ABX196, alone and in combination with anti-PD-1 antibody, as a novel strategy to overcome the immunosuppressive microenvironment and to produce antitumor activity.

ABX464 (obefazimod) for moderate-to-severe, active ulcerative colitis: a phase 2b, double-blind, randomised, placebo-controlled induction trial and 48 week, open-label extension.

BACKGROUND: ABX464 (obefazimod) is a small molecule that selectively upregulates miR-124 in immune cells. We aimed to assess ABX464 as a treatment for patients with moderate-to-severe, active ulcerative colitis. METHODS: In this phase 2b, double-blind, randomised, placebo-controlled induction trial, patients were recruited from 95 centres (hospitals and health-care centres) in 16 countries. Eligible patients were aged 18-75 years, with a diagnosis of moderate-to-severe, active ulcerative colitis and a modified Mayo Score (MMS) of 5 points or higher, and a documented non-response or intolerance to previous treatment. Enrolled patients were randomly assigned (1:1:1:1) via an interactive voice and web response system to receive once daily oral ABX464 100 mg, ABX464 50 mg, ABX464 25 mg, or matched placebo. Randomisation was stratified according to study site (US vs non-US) and to whether the patient had previous exposure to second-line treatment with biologics or JAK inhibitors. The primary endpoint was the change from baseline in MMS at week 8. The primary efficacy analysis was done in the full analysis set (FAS), defined as all randomly assigned patients who received at least one dose of study treatment and had baseline data for at least one efficacy variable, and was analysed according to the principles of intention-to-treat. Safety analyses included patients who had been randomly assigned and who received at least one dose of study treatment. The 96 week open-label extension is ongoing. This study is registered with ClinicalTrials.gov, NCT04023396. FINDINGS: Between Aug 13, 2019, and April 16, 2021, 254 patients were randomly allocated to ABX464 100 mg (n=64), ABX464 50 mg (n=63), ABX464 25 mg (n=63), or placebo (n=64). Two patients, both in the ABX464 25 mg group, were excluded from the FAS. In the FAS at week 8, the least squares mean (LSM) change from baseline in MMS was -2·9 (95% CI -3·4 to -2·5) for the ABX464 100 mg group, -3·2 (-3·7 to -2·7) for the ABX464 50 mg group, -3·1 (-3·6 to -2·6) for the ABX464 25 mg group, and -1·9 (-2·4 to -1·5) for placebo group; the magnitude of the difference in MMS from baseline was significantly greater in all three ABX464 groups compared with placebo (p=0·0039 for ABX464 100 mg vs placebo, p=0·0003 for ABX464 50 mg vs placebo, and p=0·0010 for ABX464 25 mg vs placebo). The most frequently reported adverse event was headache, which was reported for 27 (42%) of 64 patients in the ABX464 100 mg group, 19 (30%) of 63 in the 50 mg group, 13 (21%) of 62 in the 25 mg group, and five (8%) of 64 in the placebo group. Severe (grade 3) headache was reported for three (5%) patients in the ABX464 group 100 mg group, two (3%) in the ABX464 50 mg group, one (2%) in the ABX464 25 mg group, and none in the placebo group. The only serious adverse event reported for two or more patients in any group was ulcerative colitis (one in each of the ABX464 100 mg and 50 mg groups, and three [5%] in the placebo group). INTERPRETATION: All doses of ABX464 significantly improved moderate-to-severe, active ulcerative colitis compared with placebo, as measured by changes in MMS from baseline to week 8. A phase 3 clinical programme is ongoing. FUNDING: Abivax.

A clinical trial of a whole-virus H5N1 vaccine derived from cell culture.

BACKGROUND: Widespread infections of avian species with avian influenza H5N1 virus and its limited spread to humans suggest that the virus has the potential to cause a human influenza pandemic. An urgent need exists for an H5N1 vaccine that is effective against divergent strains of H5N1 virus. METHODS: In a randomized, dose-escalation, phase 1 and 2 study involving six subgroups, we investigated the safety of an H5N1 whole-virus vaccine produced on Vero cell cultures and determined its ability to induce antibodies capable of neutralizing various H5N1 strains. In two visits 21 days apart, 275 volunteers between the ages of 18 and 45 years received two doses of vaccine that each contained 3.75 microg, 7.5 microg, 15 microg, or 30 microg of hemagglutinin antigen with alum adjuvant or 7.5 microg or 15 microg of hemagglutinin antigen without adjuvant. Serologic analysis was performed at baseline and on days 21 and 42. RESULTS: The vaccine induced a neutralizing immune response not only against the clade 1 (A/Vietnam/1203/2004) virus strain but also against the clade 2 and 3 strains. The use of adjuvants did not improve the antibody response. Maximum responses to the vaccine strain were obtained with formulations containing 7.5 microg and 15 microg of hemagglutinin antigen without adjuvant. Mild pain at the injection site (in 9 to 27% of subjects) and headache (in 6 to 31% of subjects) were the most common adverse events identified for all vaccine formulations. CONCLUSIONS: A two-dose vaccine regimen of either 7.5 microg or 15 microg of hemagglutinin antigen without adjuvant induced neutralizing antibodies against diverse H5N1 virus strains in a high percentage of subjects, suggesting that this may be a useful H5N1 vaccine. (ClinicalTrials.gov number, NCT00349141.)

Preclinical testing of human recombinant von Willebrand factor: ADAMTS13 cleavage capacity in animals as criterion for species suitability.

Von Willebrand factor (VWF) is cleaved by the plasma metalloprotease ADAMTS13 ( A Disintegrin and Metalloproteinase with Thrombo Spondin repeats, number 13) that regulates the hemostatic activity of VWF by limiting its multimeric size in the human system. In vitro and ex vivo studies have shown that human recombinant VWF (rVWF) is virtually resistant to the proteolytic activity of murine ADAMTS13. In contrast, rabbit and cynomolgus ADAMTS13 is able to cleave human rVWF. These findings were consistent with in vivo results showing distinct pharmacological behavior of human rVWF depending on the cleaving capacity of ADAMTS13 present in the species tested. Studies were performed using three mouse strains (ADAMTS13 deficient, C57BL/6J [wild type], VWF deficient), rats, rabbits, and cynomolgus monkeys. All animals were infused once with different doses of human rVWF and, in addition, 14 daily doses were given to rats and cynomolgus monkeys. Exaggerated pharmacological effects were observed in mice, with the ADAMTS13 knockout mouse being the most sensitive strain. Similar findings with decreased incidence and severity were seen in normal C57BL/6J mice and also in VWF-deficient mice, where they were least pronounced. In rats, exaggerated pharmacological effects were observed only after 14 doses. Rabbits and cynomolgus monkeys showed no exaggerated pharmacological effects. These differences between species and between mouse strains suggest that the efficiency of ADAMTS13 to cleave rVWF determines the severity of clinical, laboratory and pathohistological findings. These observations highlight the importance of evaluating species' suitability for the generation of meaningful preclinical data for determining the therapeutic safety margins for human patients. Only animals with a sufficient rVWF cleavage capacity by endogenous ADAMTS13 (rabbits and cynomolgus monkeys) are considered appropriate animal models for preclinical evaluation of the rVWF product.

Structure and function of a recombinant von Willebrand factor drug candidate.

The complex structure, large size, and multiple posttranslational modifications of von Willebrand factor (VWF) presented a technological challenge for the production of recombinant VWF (rVWF). Nonetheless, we developed an rVWF product for treating von Willebrand disease, whereupon rVWF is coexpressed with recombinant factor VIII (rFVIII) in Chinese hamster ovary cells used to produce rFVIII for the treatment of hemophilia A. Here we describe the characterization of the structure and function of the rVWF drug product, with a focus on its in vitro platelet aggregation and matrix protein binding functions. Electron microscopy and multimer analysis revealed a highly organized structure for the rVWF protein, with a homogeneous multimer distribution including ultrahigh molecular weight multimers. The specific activity for binding to collagen and platelets mediated by ristocetin is higher in rVWF than in commercial plasma-derived VWF-FVIII complex products. The affinity and binding capacity of rVWF to FVIII is comparable to VWF in plasma. rVWF effectively binds to platelets and promotes platelet adhesion under shear stress similar to VWF in human plasma.

A close look at human IgG sialylation and subclass distribution after lectin fractionation.

Polyspecific human IgG preparations are indicated for the treatment of primary immunodeficiency disorders associated with defects in humoral immunity. In addition, intraveneous IgG (IVIG) is used to treat patients with autoimmune and systemic inflammatory diseases. Lectin chromatography on Sambucus nigra agglutinin stood at the cradle of the hypothesis that the anti-inflammatory properties depend on sialylation of the N-glycans in the Fc region of IgG. A detailed analysis of fractions obtained by lectin chromatography revealed that binding of IVIG is essentially mediated by Fab glycosylation. Moreover, experiments with a monoclonal antibody from a human cell line and IVIG Fc fragments indicated that at least two sialic acids in the Fc region of an antibody are required for lectin binding. Such glycoforms contain either two monosialylated glycans or a disialylated glycan and constitute 1% or less of the total human IgG. Arguably this small proportion holds the entire anti-inflammatory potency. A new mass spectrometric quantification method of IgG subclass ratio revealed that the IVIG Fc preparation essentially consists of IgG1. This observation may be relevant when studying the effect of human Fc in murine models of inflammation because mouse IgG subclasses differ substantially in their interaction with receptors.

Seropersistence of tick-borne encephalitis antibodies, safety and booster response to FSME-IMMUN 0.5 ml in adults aged 18-67 years.

A clinical study was carried out to evaluate the persistence of tick-borne encephalitis (TBE) antibodies 2 and 3 years after a primary vaccination series (three-dose regimen), and to assess the antibody response to a booster vaccination with FSME-IMMUN. Volunteers (N = 347, 18-67 years) who had received two doses of either FSME-IMMUN or Encepur adults and a third vaccination with FSME-IMMUN were enrolled. Seropositivity rates were assessed by ELISA and neutralization test (NT). After the primary series, seropositivity rates were 99.1% as determined by ELISA and 100% by NT, decreasing to 85% and 96.8% in the first two years and to 88.7% and 95.4% after 3 years. Following booster vaccination, 100% of subjects were seropositive. Age was the only variable with a significant influence on the probability of remaining TBE seropositive 2 or 3 years after the third vaccination. In subjects aged 18-50 years, the pre-booster seropositivity rate was higher (88.7% and 92.3% after 2 and 3 years, respectively) than in those aged 51-67 years (65.5% and 70.9% after 2 and 3 years, respectively). Adverse events after booster vaccination occurred with a low frequency and were predominantly mild. An annual TBE antibody decline rate of 0.58 (based on NT) was estimated to lead to antibody titer decrease from e.g., 260 to 45.6 after 3 years. To conclude, a booster vaccination with FSME-IMMUN, administered 3 years after primary vaccination, is well tolerated and induces a

Safety, tolerability and impact on viral reservoirs of the addition to antiretroviral therapy of ABX464, an investigational antiviral drug, in individuals living with HIV-1: a Phase IIa randomised controlled study.

OBJECTIVES: To assess the safety and tolerability as well as antiretroviral impact of ABX464, an oral investigational drug with a novel mechanism of HIV-1 inhibition (ClinicalTrials.gov NCT02735863). METHODS: Randomised, double-blind, placebo-controlled, Phase IIa study in individuals living with HIV-1 on antiretroviral therapy at six clinical centres in Spain, France and Belgium. ABX464 was administered once a day to 22 fully controlled HIV-1-positive participants at two doses (50 mg, n=6 and 150 mg, n=16) versus placebo, which was given to eight participants for 28 days in combination with a boosted protease inhibitor (darunavir/ritonavir or darunavir/cobicistat). The primary objective of the study was to assess ABX464 safety and tolerability when used in combination with darunavir boosted therapy. The secondary objective was to study antiretroviral efficacy on viral reservoirs using time to viral rebound following treatment interruption. The impact of ABX464 on HIV-1 reservoirs was further assessed by measuring levels of total HIV-1 in peripheral blood mononuclear cells (PBMCs) in the intervention arm versus placebo. A positive response was defined as an absolute reduction in HIV-1 DNA of at least 50 copies/106 PBMCs and a relative decrease >25% of HIV-1 DNA level. RESULTS: Twenty-six of the 30 randomly allocated participants completed the study according to the study protocol. ABX464 was found to be safe and well tolerated with the majority of adverse events (AEs) being mild or moderate. Of the participants, 22 (73.3%) experienced treatment-associated AEs (93.8%, 66.7%, 37.5% in the ABX464 150-mg, 50-mg dose and placebo arms, respectively). Percentages for combined grade 3/4 AEs for the three arms were 6.3%, 0% and 12.5%, respectively. Median time (Kaplan-Meier estimates) to viral rebound for ABX464 150-mg, 50-mg and placebo arms were 12.0 (95% confidence interval [CI]: 10-15), 15.5 (95% CI 14-22) and 15.5 (95% CI 1-22) days, respectively with no significant difference between the 150-mg treatment arm and placebo. Median changes in total HIV-1 DNA copies/106 PBMCs for ABX464 150-mg, 50-mg and placebo arms after 28 days of treatment were -40 (range -434 to +194), -115 (range -116 to -114) and 25 (range -35 to +218), respectively, showing a decrease in the intervention arms. There were 6/14, 2/2, and 0/4 responders for ABX464 150 mg, 50 mg and placebo, respectively. No significant difference was seen between treatment arms and placebo with respect to these virological parameters. CONCLUSIONS: This small controlled study confirmed the good safety and tolerability of ABX464 and provides some evidence of a potential reduction of the HIV-1 reservoir in terms of HIV-1 DNA levels in PBMCs when it was added to an HIV-1 protease inhibitor-based regimen. These results will need to be confirmed in a larger study.

Safety and immunogenicity of a vero cell culture-derived whole-virus H5N1 influenza vaccine in chronically ill and immunocompromised patients.

The development of vaccines against H5N1 influenza A viruses is a cornerstone of pandemic preparedness. Clinical trials of H5N1 vaccines have been undertaken in healthy subjects, but studies in risk groups have been lacking. In this study, the immunogenicity and safety of a nonadjuvanted cell culture-derived whole-virus H5N1 vaccine were assessed in chronically ill and immunocompromised adults. Subjects received two priming immunizations with a clade 1 A/Vietnam H5N1 influenza vaccine, and a subset also received a booster immunization with a clade 2.1 A/Indonesia H5N1 vaccine 12 to 24 months later. The antibody responses in the two populations were assessed by virus neutralization and single radial hemolysis assays. The T-cell responses in a subset of immunocompromised patients were assessed by enzyme-linked immunosorbent spot assay (ELISPOT). The priming and the booster vaccinations were safe and well tolerated in the two risk populations, and adverse reactions were predominantly mild and transient. The priming immunizations induced neutralizing antibody titers of ≥1:20 against the A/Vietnam strain in 64.2% of the chronically ill and 41.5% of the immunocompromised subjects. After the booster vaccination, neutralizing antibody titers of ≥1:20 against the A/Vietnam and A/Indonesia strains were achieved in 77.5% and 70.8%, respectively, of chronically ill subjects and in 71.6% and 67.5%, respectively, of immunocompromised subjects. The T-cell responses against the two H5N1 strains increased significantly over the baseline values. Substantial heterosubtypic T-cell responses were elicited against the 2009 pandemic H1N1 virus and seasonal A(H1N1), A(H3N2), and B subtypes. There was a significant correlation between T-cell responses and neutralizing antibody titers. These data indicate that nonadjuvanted whole-virus cell culture-derived H5N1 influenza vaccines are suitable for immunizing chronically ill and immunocompromised populations. (This study is registered at ClinicalTrials.gov under registration no. NCT00711295.).

Vero cell culture-derived pandemic influenza vaccines: preclinical and clinical development.

Several subtypes of influenza A viruses with pandemic potential are endemic in bird populations throughout Asia, Africa and the Middle East, and evidence suggests that these viruses are adapting to the mammalian host. As emphasized by the high mortality rate of humans infected with H5N1 viruses, this situation presents a substantial risk to global human health. The Vero cell culture platform has been used to develop whole-virus influenza vaccines that provide broad cross-clade protection against viruses with pandemic potential, at low antigen doses, without the requirement for adjuvantation. The safety and immunogenicity of these vaccines has been demonstrated in studies with more than 10,000 individuals, including healthy adult and elderly subjects, children and various risk groups. These Vero cell-derived vaccines are licensed for prepandemic and pandemic use. The Vero platform is also being explored to develop next-generation live-attenuated and recombinant vaccines.