A First-in-Human Randomized Study to Assess the Safety, Tolerability, Pharmacokinetics, and Neutralization Profile of Two Investigational Long-Acting Anti-SARS-CoV-2 Monoclonal Antibodies

INTRODUCTION

COVID-19 remains a significant risk for the immunocompromised given their lower responsiveness to vaccination or infection. Therefore, passive immunity through long-acting monoclonal antibodies (mAbs) offers a needed approach for pre-exposure prophylaxis (PrEP). Our study evaluated safety, anti-SARS-CoV-2 neutralizing activity, nasal penetration, and pharmacokinetics (PK) of two half-life-extended investigational mAbs, AER001 and AER002, providing the first demonstration of upper airway penetration of mAbs with the LS-modification.

METHODS

This randomized, double-blind, placebo-controlled phase I study enrolled healthy adults (n = 80) who received two long-acting COVID mAbs (AER001 and AER002), AER002 alone, or placebo. The dose ranged from 100 mg (mg) to 1200 mg per mAb component. The primary objective was to describe the safety and tolerability following intravenous (IV) administration. Secondary objectives were to describe PK, anti-drug antibodies (ADA), neutralization activity levels, and safety evaluation through 6 months of follow-up.

RESULTS

The majority (97.6%) of the reported adverse events (AE) post administration were of grade 1 severity. There were no serious adverse events (SAE) or ADAs. AER001 and AER002 successfully achieved an extended half-life of 105 days and 97.5 days, respectively. Participants receiving AER001 and AER002 (300 mg each) or AER002 (300 mg) alone showed 15- and 26-fold higher neutralization levels against D614G and omicron BA.1 than the placebo group 24 h post-administration. Single 300 or 1200 mg IV dose of AER001 and AER002 resulted in nasal mucosa transudation of approximately 2.5% and 2.7%, respectively.

CONCLUSION

AER001 and AER002 showed an acceptable safety profile and extended half-life. High serum neutralization activity was observed against D614G and Omicron BA.1 compared to the placebo group. These data support that LS-modified mAbs can achieve durability, safety, potency, and upper airway tissue penetration and will guide the development of the next generation of mAbs for COVID-19 prevention and treatment.

TRIAL REGISTRATION

EudraCT Number 2022-001709-35 (COV-2022-001).

Classical swine fever virus-specific cytotoxic T lymphocytes and identification of a T cell epitope

Classical swine fever virus (CSFV)-specific cytotoxic T lymphocytes (CTL) were derived from peripheral blood mononuclear leukocytes of immunized NIH-minipigs (MHC d/d haplotype) after in vitro restimulation with infectious CSFV. Their cytotoxic activity was determined against CSFV-infected target cells obtained from simian virus 40 (SV40) large T antigen-transfected immortalized kidney cells of a syngeneic miniature swine. Experiments with separated effector cell populations revealed that the CSFV-specific cytotoxic activity was mediated by CD4(-)CD6+CD8+ MHC class I-restricted T lymphocytes. Infection of target cells with various vaccinia virus/CSFV recombinants led to the identification of a major antigenic site for CSFV-specific CTL near the cleavage site between the non-structural proteins p80 (NS3) and p10 (NS4a). Using synthetic overlapping nonapeptides which covered this protein region the sequence ENALLVALF is the first sequence to be identified as an MHC class I-restricted T cell epitope recognized by CSFV-specific CTL.

Classical swine fever virus: independent induction of protective immunity by two structural glycoproteins

To study which proteins of classical swine fever virus (CSFV) are able to confer protective immunity in swine, N-terminal autoprotease, viral core protein, and the three structural glycoproteins were expressed via vaccinia virus recombinants (VVR). CSFV proteins synthesized in cells infected with VVR showed migration characteristics on sodium dodecyl sulfate gels identical to those of their respective CSFV counterparts. Apparently authentic dimerization of the recombinant glycoproteins was observed. The glycoproteins E0 and E2 were detected on the surfaces of VVR-infected cells. In protection experiments, swine were immunized with the different VVR, and the generation of humoral immune response was monitored. Only animals vaccinated with VVR expressing E0 and/or E2 resisted a lethal challenge infection with CSFV. Glycoprotein E0 represents a second determinant for the induction of protective immunity against classical swine fever.