Vaccine Info

S-Trimer (SCB-2019) COVID-19 Vaccine

S-Trimer (SCB-2019) COVID-19 Vaccine Description

S-Trimer (SCB-2019) is a trimeric SARS-CoV-2 spike (S)-protein subunit vaccine candidate developed by Clover Pharmaceuticals by combining the trimeric SARS-CoV-2 spike (S)-protein with the company’s proprietary Trimer-Tag© technology.

Similar to other enveloped RNA viruses such as HIV, RSV, and Influenza, SARS-CoV-2 is also an RNA virus that has a trimeric spike (S) protein on its viral envelope. The trimeric S protein of SARS-CoV-2 is responsible for binding to host cell surface receptor ACE2 and subsequent viral entry, making it the primary target antigen for vaccine development. The S-Trimer vaccine resembles the native trimeric viral spike protein and is produced via a rapid mammalian cell-culture based expression system.

Trimer-Tag is an innovative drug development platform that allows the production of novel, covalently-trimerized fusion proteins. Many major disease targets are trimerization-dependent such as the tumor necrosis factor superfamily (involved in extrinsic apoptosis, immune co-stimulation, and inflammation) as well as enveloped RNA virus antigens responsible for entry into host cells.

The protein-based SCB-2019 COVID-19 vaccine candidate in combination with adjuvants from GSK or Dynavax induces a strong immune response and protection against SARS-CoV-2 in animal models.

Preclinical data as shown Clover’s protein-based adjuvanted COVID-19 vaccine candidate, S-Trimer, induces a strong neutralizing immune response in animals and protects nonhuman primates from a SARS-CoV-2 challenge. And strong immune response and protection were observed with adjuvant systems from GSK and Dynavax. These positive preclinical data supported the decision to progress adjuvanted vaccine candidates using both adjuvants into Clover’s ongoing Phase 1 clinical study of S-Trimer in healthy adult and elderly participants, said the company on September 25, 2020.

Clover is exploring development pathways for the S-Trimer vaccine to be made accessible to populations in China and globally if it is proven to be safe and effective.

On November 3, 2020, CEPI extended its partnership with Clover Biopharmaceuticals to fund the COVID-19 vaccine candidate through global Phase 2/3 study to licensure. CEPI’s total investment in Clover’s  S-Trimer vaccine candidate will be up to $328 million, including previously announced commitments of $69.5 million which have funded preclinical studies and Phase 1 clinical trials.

The new CEPI funding will also fund additional clinical studies in special populations, such as people with autoimmune conditions, immunocompromised individuals, pregnant women, and children. In parallel to the clinical development process, the program will continue scaling up the manufacturing process to potentially allow the production of more than one billion doses annually, and build up vaccine inventory which – if the vaccine is proven to be safe and effective - could be deployed rapidly upon licensure.

Joshua Liang is the Chief Strategy Officer of Clover Biopharmaceuticals and co-inventor of the COVID-19 S-Trimer vaccine. Clover Biopharmaceuticals is a global clinical-stage biotechnology company based in Chengdu, China, focused on discovering and developing transformative biologic therapies and vaccines.

S-Trimer (SCB-2019) COVID-19 Vaccine Indication

SCB-2019 COVID-19 is indicated to prevent SARS-CoV-2 infection which causes COVID-19 disease.

No pediatric vaccine efficacy has been disclosed.

S-Trimer (SCB-2019) COVID-19 Vaccine News

November 3, 2020 - The Coalition for Epidemic Preparedness Innovations announced that it will fund the development of the protein-based S-Trimer COVID-19 vaccine candidate by China-based Sichuan Clover Biopharmaceuticals, Inc. through a global pivotal Phase 2/3 efficacy clinical trial and to licensure in China and globally if the vaccine is proven to be safe and effective.

September 25, 2020 - Clover Biopharmaceuticals Announces Positive Preclinical Data and Updates on Phase 1 Study for its Adjuvanted S-Trimer COVID-19 Vaccine Candidate.

July 8, 2020 - The Coalition for Epidemic Preparedness Innovations announced the expansion of its partnership with Sichuan Clover Biopharmaceuticals, Inc. to rapidly advance the development and manufacture of Clover’s protein-based COVID-19 S-Trimer vaccine candidate, which is based on Clover’s proprietary Trimer-Tag© vaccine technology platform.

June 19, 2020 - Clover Biopharmaceuticals announced that the first participants have been dosed in the Phase 1 first-in-human study evaluating the company’s COVID-19 S-Trimer subunit vaccine candidate (SCB-2019), which is based on Clover’s proprietary Trimer-Tag vaccine technology platform.

S-Trimer (SCB-2019) COVID-19 Vaccine Clinical Trial

Clinical Trial NCT04405908 SCB-2019 as COVID-19 Vaccine - Last Update Posted: June 23, 2020.

  • This is a randomized, double-blind, placebo-controlled, first-in-human (FIH) study to assess safety, reactogenicity, and immunogenicity of SCB-2019 at multiple dose levels, administered as 2 injections IM in healthy subjects.
  • In June 2020, Clover announced the start of a Phase 1 clinical trial. The trial is a randomized, observer-blind, placebo-controlled study to assess the safety, reactogenicity and immunogenicity of the adjuvanted COVID-19 S-Trimer vaccine at multiple dose levels.
  • The study has completed enrollment of 150 adult and elderly participants. Preliminary results show that the vaccine is likely to be safe and well-tolerated, with high levels of neutralizing antibodies observed. Based on these preliminary results, an additional 200 participants will be enrolled in a Phase 1 dose-expansion study at the selected S-Trimer dose-level and adjuvanted with either GSK’s pandemic adjuvant or Dynavax’s advanced adjuvant CpG 1018 plus alum.
  • Clover intends to initiate a global Phase 2/3 vaccine efficacy study before the end of 2020. Detailed Phase 1 data will be made available in a peer-reviewed publication in the near future. The clinical trials and Clover’s COVID-19 vaccine program are being supported by funding and collaboration with the Coalition for Epidemic Preparedness Innovations.