Antibody combination treats Omicron infections

A new monoclonal antibody combination can prevent and treat Omicron infections in monkeys, researchers reported on Monday in Nature Microbiology.

The antibodies, called P2G3 and P5C3, recognize specific regions of the spike protein the SARS-CoV-2 virus uses to enter cells. “P5C3 alone can block all SARS-CoV-2 variants that had dominated the pandemic up to Omicron BA.2,” said Dr. Didier Trono of the Swiss Institute of Technology in Lausanne.

“P2G3 then comes to the rescue as it not only can neutralize all previous SARS-CoV-2 variants of concern, but it can also block BA.4 and BA.5,” he said. “P2G3 is even effective against some BA.2 or BA.4/BA.5 mutants capable of escaping (Eli Lilly’s (LLY.N)) bebtelovimab, the only antibody approved for the clinics still displaying activity against the currently dominant BA.4/BA.5 subvariants.”

In lab experiments, mutations that might make SARS-CoV-2 variants resistant to P2G3 did not allow escape from P5C3, and P5C3 escape mutants were still blocked by P2G3, Trono said. “In essence, the two antibodies cover for each other, one filling in for the lapses of the other and vice versa.”

Aerium Therapeutics plans to start testing the combination in humans next month, said Trono, who is among the company’s founders. If larger trials eventually confirm its effectiveness, the P5C3/P2G3 combination will be given by injection every three-to-six months to people who are immunocompromised and do not have a strong response to COVID-19 vaccines, the company has said.