Amid a sweeping National Security Law passage, many biotech and healthcare firms from China opt for a Hong Kong initial public offering in the meanwhile appetite for a US listing wanes.

The 10-year partnership brings Arcus up-front funding with ample earnout opportunities, while Gilead gets extensive opt-in rights and an equity stake it can increase – and potentially a wholly owned dual checkpoint combination.

In a bipartisan move, the US Senate is moving to impose new rules on companies - including those from China - seeking US initial public offerings, adding further uncertainty over such plans and further stoking trade tensions.

Vir began pursuing immunological approaches to infectious diseases three years before its COVID-19 work. Its hepatitis B, flu and HIV clinical trials are delayed about six months due to coronavirus-related issues.