Monoclonal Antibody Being Developed for Treatment and Prevention of COVID-19, Variants

A monoclonal antibody developed for both the treatment and prevention of COVID-19 displayed neutralizing activity against the virus as well as protection against it in animal models.

The monoclonal antibody named ADG2 was “engineered to possess high potency and broad neutralization against SARS-CoV, SARS-CoV-2, and pre-emergent SARS-like-CoVs. ADG20, a half-life extended version of ADG2, is being developed for the prevention and treatment of coronavirus disease (COVID-19)," the investigators wrote. "ADG2 and ADG20 displayed potent neutralizing activity against the original SARS-CoV-2 strain and all known variants of concern and provided significant protection against SARS and COVID-19 in mouse models.”

The data was presented virtually at the 23rd Annual Making a Difference in Infectious Disease Meeting 2021 virtual sessions

“ADG2 displayed potent neutralizing activity against SARS-CoV (IC50 of 4–8 ng/mL) and SARS-CoV-2 (IC50 of ~1 ng/mL) and bound with high affinity to RBDs of 12/13 clade 1 SARS-like-CoVs, with a KDAPP of 0.24–1.12 nM. ADG2 bound to all SARS-CoV-2 variants tested at levels ≥50% of wild-type (WT) SARS-CoV-2; whereas loss of binding (>75% reduced relative to WT) to one or more variants was observed for other clinical mAbs,” the investigators reported. “ADG20 also displayed little to no reduction (<4-fold) in neutralizing activity across 3 variants of concern (P.1, B.1.351, B.1.1.7), with all reaching a plateau at 100% neutralization.”

The company that developed the monoclonal therapy is Adimab. They announced last summer that it had launched Adagio Therapeutics, which is a biotechnology company that will develop a portfolio of anti-coronavirus antibodies as both therapeutics and prophylactics against COVID-19 and future coronaviruses.

In February, Adagio announced it began its phase 1 trial for ADG20. “We are in the unique position of having a monoclonal antibody that binds to and protects against common circulating SARS-CoV-2 variants as well as SARS-related viruses with pandemic potential,” Adagio CEO Tillman Gerngross, said at that time. “This broadly neutralizing activity was intentionally designed into ADG20, as we anticipated the continued emergence of resistance mutations, and we took deliberate steps to engineer ADG20 to maximize its potential to avoid viral escape. This design feature also enables ADG20 to target and neutralize coronaviruses that may emerge in the future.”