Sanofi and GSK Launch Phase 1/2 Clinical Trial for Adjuvanted Recombinant Protein-Based COVID-19 Vaccine Candidate, Aiming for Phase 3 by Year-End

Today, Sanofi and GSK jointly announced the initiation of Phase 1/2 clinical trials for their collaboratively developed adjuvanted COVID-19 vaccine. The candidate vaccine utilizes the same recombinant protein technology as one of Sanofi’s approved seasonal influenza vaccines, combined with GSK’s proven pandemic vaccine adjuvant technology.

According to the latest statistics from the World Health Organization (WHO), 34 candidate COVID-19 vaccines have currently entered the clinical development stage. Among these, four are recombinant protein vaccines. One of them is the COVID-19 candidate vaccine jointly developed by Sanofi and GlaxoSmithKline (GSK). Sanofi’s recombinant protein vaccine technology platform supports large-scale expression of the recombinant SARS-CoV-2 spike (S) protein by using baculovirus to transfect insect cells. Sanofi’s influenza vaccine Flublok, which has been approved by the U.S. FDA, is based on this production platform. An advantage of recombinant protein candidate vaccines is their relative stability, allowing for storage and transportation at temperatures between 2°C and 8°C.

In April this year, Sanofi and GSK reached a collaboration agreement, under which GSK will provide its adjuvant technology for this candidate vaccine. This technology not only enhances the immunogenicity of the vaccine but also reduces the amount of vaccine protein required per dose, thereby enabling the production of more vaccines to help patients in need. Preclinical data show that two injections of this adjuvanted recombinant vaccine can elicit high levels of neutralizing antibodies, comparable to those observed in recovered COVID-19 patients. The preclinical results will be published later this year.

▲ R&D Plan for Sanofi/GSK COVID-19 Candidate Vaccine (Image source: Sanofi official website)

This Phase 1/2 clinical trial is a randomized, double-blind, placebo-controlled study designed to evaluate the safety, reactogenicity, and immunogenicity of a candidate COVID-19 vaccine. The study plans to enroll 440 healthy adult volunteers across 11 investigative sites. In the first stage of the trial, enrolled volunteers will be aged 18–49 years. Subsequently, the trial will recruit volunteers from a broader age range, including at least 140 volunteers aged 50 years or older.

The company expects that the first batch of results, anticipated in early December 2020, will support the initiation of Phase 3 clinical trials in December 2020. If the data are sufficient for a licensing application, regulatory approval is planned to be sought in the first half of 2021. Meanwhile, Sanofi and GSK are scaling up production of the antigen and adjuvant, with the goal of producing up to 1 billion doses of the candidate vaccine in 2021.

References:

[1] Sanofi and GSK initiate Phase 1/2 clinical trial of COVID-19 adjuvanted recombinant protein-based vaccine candidate. Retrieved September 3, 2020, from https://www.gsk.com/en-gb/media/press-releases/sanofi-and-gsk-initiate-phase-12-clinical-trial-of-covid-19-adjuvanted-recombinant-protein-based-vaccine-candidate/

[2] Draft landscape of COVID-19 candidate vaccines. Retrieved September 3, 2020, from https://www.who.int/publications/m/item/draft-landscape-of-covid-19-candidate-vaccines

[3] Sanofi and GSK move Covid-19 vaccine into human trials. Retrieved September 3, 2020, from https://www.statnews.com/2020/09/03/sanofi-gsk-covid19-vaccine-human-trials/

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