Non-human primate data sending Junshi, Lilly COVID-19 mAb to clinic
A Chinese Academy of Sciences team has provided evidence showing a mAb against SARS-CoV-2 from Lilly and Junshi is effective in monkeys -- a first for any COVID-19 mAb, according to the researchers -- and compares favorably on potency with other mAbs poised to enter the clinic.
The candidate appears to be at least as potent as other recently described SARS-CoV-2 mAbs -- including the one behind a pair of candidates from Vir Biotechnology Inc. (NASDAQ:VIR) -- although firm conclusions cannot be made due to variations in neutralization assay protocols.
Shanghai Junshi Biosciences Co. Ltd. (HKEX:1877) and Eli Lilly and Co. (NYSE:LLY) plan to begin clinical trials in the U.S. and China this quarter of the mAb, which contains Fc modifications to reduce the risk of Fc-mediated lung injury (see “Junshi Taps Lilly’s Manufacturing Capacity”).
The mAb, dubbed CB6, was isolated from a convalescent COVID-19 patient. It was described Tuesday in a Nature paper from a group that includes George Gao, who is director general of China’s Center for Disease Control and Prevention and director of the Chinese Academy of Sciences’ Key Laboratory of Pathogenic Microbiology and Immunology.
In rhesus macaques, intraperitoneal administration of 50 mg/kg of the modified CB6 on days one and three after intratracheal infection led to an immediate decline in viral RNA levels in throat swabs. By contrast, viral levels peaked at four days after infection in the control group.
In animals treated once with the same dose of the modified mAb one day before infection, viral RNA levels remained minimal or below the limit of detection.
Histological evaluation of one animal from each group showed that prophylactically and therapeutically treated monkeys exhibited limited signs of lung damage, with less pulmonary edema, fibrosis and leukocyte infiltration than the control animal, which also showed signs of thrombosis in the pulmonary capillary lumen. The treated animals also had no sign of serious small bronchi or small pulmonary capillary lesions.
The new article comes one week after Vir reported in Nature that S309, the mAb its candidates are derived from, neutralized SARS-CoV-2 in cell culture with an IC50 value of 79 ng/mL -- about half as potent as CB6, which neutralized the virus with an IC50 value of 36 ng/mL. Vir did not report animal data (see “Vir Backs Cross-reactive mAb Strategy with Preclinical Potency Data”).