ABSTRACT
SARS-CoV-2 Omicron subvariants have demonstrated extensive evasion from monoclonal antibodies (mAbs) developed for clinical use, which raises an urgent need to develop new broad-spectrum mAbs. Here, we report the isolation and analysis of two anti-RBD neutralizing antibodies BA7208 and BA7125 from mice engineered to produce human antibodies. While BA7125 showed broadly neutralizing activity against all variants except the Omicron sublineages, BA7208 was potently neutralizing against all tested SARS-CoV-2 variants (including Omicron BA.1-BA.5) except Mu. By combining BA7208 and BA7125 through the knobs-into-holes technology, we generated a biparatopic antibody BA7208/7125 that was able to neutralize all tested circulating SARS-CoV-2 variants. Cryo-electron microscopy structure of these broad-spectrum antibodies in complex with trimeric Delta and Omicron spike indicated that the contact residues are highly conserved and had minimal interactions with mutational residues in RBD of current variants. In addition, we showed that administration of BA7208/7125 via the intraperitoneal, intranasal, or aerosol inhalation route showed potent therapeutic efficacy against Omicron BA.1 and BA.2 in hACE2-transgenic and wild-type mice and, separately, effective prophylaxis. BA7208/7125 thus has the potential to be an effective candidate as an intervention against COVID-19.
ABSTRACT
INTRODUCTION: We aimed to evaluate the safety, tolerability, pharmacokinetics, and immunogenicity of a single dose of LY-CovMab in Chinese healthy adults. METHODS: We conducted a phase 1, randomized, dose-escalation, placebo-controlled trial in 42 volunteers, 18-45 years of age, and 40 out of 42 received a single dose of LY-CovMab or placebo with LY-CovMab at a dose of 30 mg, 150 mg, 600 mg, 1200 mg, and 2400 mg. There were ten subjects in each group receiving LY-CovMab or placebo in a 4:1 ratio with the exception that the 30 mg group had two subjects both receiving LY-CovMab. RESULTS: Among the 42 randomized participants, 40 received an injection with 32 administered LY-CovMab and 8 administered placebo. A total of 18 drug-related treatment-emergent adverse events (TEAEs) were reported in 12 subjects (30.0%), including protein urine present (25%, 10/40) and blood creatinine increased (7.5%, 3/40). The incidence of drug-related TEAE in each dosage group was as follows: 150 mg (28.6%, 2/7), 600 mg (25%, 2/8), 1200 mg (14.3%, 1/7), 2400 mg (50%, 4/8), and placebo (37.5%, 3/8). All drug-related TEAEs were grade 1, and most of them were recovering/resolving or recovered/resolved without taking action. The serum exposure of LY-CovMab (Cmax, AUC0-last, AUC0-inf) after intravenous infusion increased in an approximately proportional manner as the dose increased from 150 to 2400 mg. The elimination half-life (t1/2) value did not differ among different dose cohorts and was estimated to be around 28.5 days. CONCLUSIONS: A single dose of LY-CovMab was shown to be safe and well tolerated in Chinese healthy adults. The pharmacokinetic (PK) profiles of LY-CovMab in healthy adults showed typical monoclonal antibody distribution and elimination characteristics. LY-CovMab demonstrated dose proportionality. TRIAL REGISTRATION: ClinicalTrial.gov Identifier NCT04973735.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic, which has resulted in more than two million deaths at 2021 February . There is currently no approved therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target SARS-CoV-2 Spike protein. One human antibody, CA521FALA, demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521FALA showed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro. CA521FALA also demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521FALA inhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521FALA recognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 RBD in the Spike protein. CA521FALA blocks the interaction by binding all three RBDs of one SARS-CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions against COVID-19 and identifies CA521FALA a promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.