Brii Biosciences has reported that its long-acting Covid-19 neutralising antibody therapy, amubarvimab and romlusevimab, demonstrated to retain neutralising activity against the Omicron BA.2 subvariant of the SARS-CoV-2 virus.
Obtained from convalesced Covid-19 patients, amubarvimab and romlusevimab are non-competing SARS-CoV-2 monoclonal neutralising antibodies.
They were developed in partnership with the 3rd People’s Hospital of Shenzhen and Tsinghua University.
The data were analysed in in vitro pseudovirus neutralisation testing as well as using live virus neutralisation assays in independent laboratories.
The findings indicate that exposures of intravenous dose of 1000mg amubarvimab and 1000mg romlusevimab are anticipated to be above the level needed for neutralising activity against BA.2, to treat Covid-19, as per the human pharmacokinetic data on the antibody cocktail.
According to results from the live virus neutralisation assay conducted at a lab at the University of Maryland, US, the antibody therapy’s total serum concentrations remained 60 times the level needed for over 90% neutralisation against the live virus isolate BA.2, 14 days following dosing.
Consequently, even if the mutations seen in the BA.2 subvariant spike protein raise the IC50 relative to wild-type virus, substantial treatment exposures are anticipated to last for at least two weeks and more.
Existing in vitro pseudovirus testing results showed that amubarvimab and romlusevimab combination maintains activity against key variants of the virus.
The Emergency Use Authorization application for the antibody cocktail submitted by Brii Bio is being reviewed by the US Food and Drug Administration.
Brii Bio Infectious Diseases Therapy Area vice-president and head David Margolis said: “Omicron BA.2 subvariant cases now represent the majority of Covid-19 infections globally, so these data offer timely insights into the longevity and durability of the amubarvimab/romlusevimab combination as a potential new tool to help patients in need of more treatment options.
“There continues to be a critical need for highly effective therapies against Covid-19 infection, which can greatly reduce the risk of hospitalisation and death in individuals at high risk.”
In August last year, the company reported positive interim assessment findings from the Phase III ACTIV-2 trial of BRII-196 plus BRII-198 in non-hospitalised Covid-19 patients.