Singapore team's Covid-19 neutralising antibody test kit is first to get US FDA approval

cPass does not require highly specialised equipment or training to use, and returns results in just an hour. PHOTO: DUKE-NUS MEDICAL SCHOOL

SINGAPORE - A kit that detects whether someone has antibodies which neutralise the coronavirus, invented by local researchers, has become the first of its kind to receive authorisation from the United States' Food and Drug Administration (FDA).

On Friday (Nov 6), the FDA said on its website that it had given emergency use authorisation for the kit, known as cPass.

cPass was invented by a team led by Professor Wang Linfa, director of Duke-NUS' emerging infectious diseases programme, and co-developed with biotech company GenScript Biotech Corporation and the Agency for Science, Technology and Research's (A*Star) Diagnostics Development Hub (DxD Hub).

It can be used to see if vaccines work, check what proportion of the population has already been infected, and assist in contact tracing by enabling the health authorities to retrace the steps of the virus.

cPass also does not require highly specialised equipment or training to use, and returns results in just an hour.

On Sunday, Prof Wang told The Straits Times that the FDA's approval was extremely significant not just for his team, but for Singapore as well.

He said: "To have the FDA approval as the first and only commercial kit to determine neutralising antibodies for Sars-CoV-2 in the world is a very high bar to reach. This is an incredible recognition for our team and the Singapore research and biotech landscape.

"The total critical mass of Singaporean biomedical R&D is less than 1 per cent of the (world's), and yet we are the international leader in this area for Covid-19."

FDA said it had previously issued emergency use authorisation to some 50 serology tests, which also detect antibodies.

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But it added that these kits only detect the presence of binding antibodies, which bind to a virus but do not necessarily decrease its ability to infect and destroy cells.

On the other hand, neutralising antibodies, which cPass detects, are thought to prevent the coronavirus from infecting a patient's cells.

(From left) Resarch assistant Ong Xin Mei, Professor Wang Linfa, and research assistant Lim Beng Lee with the cPass test kits. PHOTO: DUKE-NUS MEDICAL SCHOOL

Prof Wang acknowledged - as he had on previous occasions - that just because someone has such antibodies does not mean they are immune to Covid-19.

But "it is agreed that neutralising antibodies definitely play an important role in granting immunity... They are the only biomarker for immunity that we can practically measure on a large scale", he said.

Dr Timothy Stenzel, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health, said that the ability to detect such antibodies can help researchers gain insights into their impact on patients.

He said: "There are still many unknowns about what the presence of Sars-CoV-2 antibodies may tell us about potential immunity, but today's authorisation gives us another tool to evaluate those antibodies as we continue to research and study this virus."

Prof Wang said that following the FDA authorisation, Duke-NUS, DxD and GenScript will work to expand the application and geographic reach of the kits.

He added that cPass will also play an important role in the search for the origin of the coronavirus as it can detect neutralising antibodies in not just humans, but any species of animals as well.

He said his team has already obtained two grants from the World Health Organisation to work on this.

DxD's chief executive, Dr Sidney Yee, said that DxD is working with labs here to deploy the kits locally.

She said: "As Singapore's national diagnostics platform, DxD Hub is pleased that this test kit... has received approval from an internationally recognised body. It gives our partners additional assurance and confidence in the quality of this diagnostic kit in supporting the fight against the global pandemic."

The Straits Times has approached the Health Ministry for information on this deployment.

Prof Wang said: "Considering we are expecting many vaccines will go into mass deployment in the next three to six months, the mass testing by cPass will form an integral part of the 'exit strategy' for Singapore and all nations globally."

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