Clover Bio of Chengdu has produced a trimeric Spike-protein (S-Trimer) subunit vaccine candidate for the Wuhan coronavirus via a mammalian cell expression system. Clover scientists have also used the newly obtained S-Trimer to detect antigen-specific antibodies in sera from recovered 2019-nCoV patients. According to company, it is the first biopharma to disclose a 2019-nCoV vaccine candidate that can be recognized by antibodies produced in previously-infected patients.

The company said 2019-nCoV is an RNA virus that has a trimeric spike (S) protein on its viral envelope, much like other enveloped RNA viruses such as HIV, RSV and influenza. The trimeric S protein of 2019-nCoV is responsible for binding to host cell surface receptor ACE2 and subsequent viral entry.

Upon knowing the genomic DNA sequence of 2019-nCoV last month, Clover scientists immediately started designing the viral S-protein construct and completed its gene synthesis. Using its patented Trimer-Tag© technology, Clover produced a S-Trimer subunit vaccine that resembles the native trimeric viral spike via a rapid mammalian cell-culture based expression system.

Clover claims to have one of the largest in-house, commercial-scale cGMP biomanufacturing capabilities in China, which could scale up rapidly and produce large-quantities of a coronavirus vaccine.

Previously, Clover has developed recombinant subunit-Trimer vaccines for RSV and influenza viruses via its Trimer-Tag© technology.

“I am very excited that Clover has achieved high-level expression of the native-like trimeric viral Spike protein (S-Trimer) in mammalian cells in record time, and importantly, we have used the newly-obtained vaccine candidate to successfully detect viral S protein-specific antibodies from the sera of multiple patients who recently recovered from 2019-nCoV infection in China," said Dr. Peng Liang, co-founder, Chairman and President of Clover. "The implication of this discovery is that it not only has validated the correct conformation of our S-Trimer subunit vaccine candidate, but also further supports that the new 2019-nCov virus is indeed the culprit for the current epidemic, since all previous diagnosis for the viral infections have been based on nucleic acid detection."

“We are encouraged by the rapid progress of our S-Trimer vaccine development for 2019-nCoV and hope to support global efforts in fighting this epidemic,” said Joshua Liang, Chief Strategy Officer and Board Director at Clover. “To this end, we recognize that collaborations will be critical to accelerating the development of a successful new vaccine in times of emergency, and we invite any interested regulatory, academic or industry parties to contact us for this noble common cause.”
Clover Bio has raised more than $100 million in total capital since 2016. It uses its proprietary Trimer-Tag© technology platform to develop novel biologics targeting trimerization-dependent pathways. The company also has in-house cGMP biomanufacturing capabilities for select biosimilars.

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Disclosure: none.