GSK & Sanofi Back for a Phase 2 Vaccine Trial in U.S., Honduras & Panama Financed by U.S. Gov

GSK & Sanofi Back for a Phase 2 Vaccine Trial in U.S., Honduras & Panama Financed by U.S. Gov

Two major European pharmaceutical manufacturers, France-based Sanofi and UK-based GlaxoSmithKline (GSK) found setbacks toward the end of 2020 with an investigational vaccine product as the study produced disappointing outcomes. Hence the experimental COVID-19 vaccine candidate was pushed back as the “insufficient” immune response in participants over 50 led them to consider a Plan B. Apparently, the two companies went back to the lab to adjust the vaccine formulation and now plan to test a trio of doses in a new Phase 2 clinical trial involving 720 adults in the United States, Honduras, and Panama. With an ambitious timeline and government funding, they are back to test the safety, reactogenicity and immunogenicity of this updated investigational product.

Why was the previous data wasn’t sufficient?

By December 2020, the two sponsors had generated data from a Phase 1/2 clinical trial revealing that an immune response comparable to patients who had recovered from COVID-19 in adults 18 to 49 years, but a lower immune response in older adults, likely due to an insufficient concentration of the antigen.

What have the two done with their virus?

Thomas Triomphe, Executive Vice President and Head of Sanofi Pasteur, reported in a joint press releases that “Over the past few weeks our teams have worked to refine the antigen formulation of our recombinant-protein vaccine, based on learnings from our initial Phase 1/2 study.” The executive continued, “We are confident that our vaccine candidate has strong potential and we are very encouraged by the latest preclinical data. This new Phase 2 study will enable us to identify the final vaccine formulation for adults of all ages.”

While Roger Connor, President of GSK Vaccines, shared with the world that “The world needs multiple vaccines and we are confident that combining our proven pandemic adjuvant system with this improved antigen formulation will have significant potential as the pandemic evolves. We look forward to further progressing this vaccine candidate to Phase 3 in Q2 2021, if this Phase 2 study is successful.”

Does Sanofi have a fresh POV given the emergence of the variant?

Possibly. At least from the standpoint of their press release, these variants are top of mind and both Sanofi and GSK commenced development targeting these variants. Now is this more and above what the other vaccine makers are doing—we can’t say here at TrialSite but are certain Pfizer, Moderna, Johnson & Johnson, Novavax and others such as CureVac are mindful of the importance of addressing the variants. 

What about the Phase 2 study?

This Phase 2 randomized, double-blind, multi-center dose finding study (NCT04762680) will be conducted on those 18 and above to evaluate the safety, reactogenicity and immunogenicity of two injections given 21 days apart. This study will include equal numbers of adults 18 to 59 and those 60 years and above.

The sponsors will test various antigen doses with a fixed dose of adjuvant in a total study population of 720 volunteers in the U.S., Honduras and Panama. The sponsors declared that results of the Phase 2 outcomes will inform the Phase 3 protocol.

With three arms, this study is first and foremost primarily a safety study as evidenced by its number one endpoint measuring presence of immediate adverse events. Follow the link to the study description for all primary and secondary outcome measures.

What is the nature of the partnership?

Sanofi and GSK came together to complement their efforts in developing a vaccine targeting COVID-19. Sanofi provides its recombinant antigen and GSK contributes its pandemic adjuvant, both established vaccine platforms that have proven successful against influenza. 

What advantages does the recombinant technology combined with GSK’s adjuvant offer?

Advantages of stability at temperatures used for routine vaccines as well as the ability to generate high and sustained responses, and the potential to prevent virus transmission. Note that one drawback of this investigational product is that it still requires two jabs. Note the Johnson & Johnson investigational product for example only requires one shot.

Who is financing this Phase 2 study?

The U.S. government has again stepped in to help subsidize these trials. The advancement of the trial program is supported by the United States’ Biomedical Advanced Research and Development Authority (BARDA), part of the HHS Office of the Assistant Secretary for Preparedness and Response under contract W15QKN-16-9-1002. Sanofi and GSK’s adjuvanted recombinant protein-based COVID-19 vaccine candidate was selected in July 2020 by the U.S. government in order to accelerate its development and manufacturing.

Call to Action: If the Phase 2 trial is positive, a global Phase 3 study will commence by Q2 2021. Based on the two sponsors’ planning, they would seek a regulatory submission by Second Half 2021 with a vaccine available to the market by Q4 2021, assuming approval by regulatory authorities.


  1. Now Panama is getting a voice in the government from two lawmakers who are believing that ivermectin will safely help slow the COVID-19 virus from spreading
    Two legislators on Tuesday vowed to push through with a plan to distribute Ivermectin drug through an “Ivermectin Pan-Three” for those who are in dire need of the controversial drug.

    To equate both the “sense of urgency and inherent trait of community sharing,” Sagip Rep. Rodante Marcoleta and Anakalusugan Rep. Mike Defensor said each beneficiary would get a minimum of three capsules/tablet free of charge.

    The Ivermectin Pan-Three will be formally launched on Thursday at the Matandang Balara Hall Park.

    “From the experts’ collective testimony, Ivermectin had been widely used to treat a variety of human parasites since its introduction in 1981 and since then, is being taken along with Vitamins C and D, melatonin, zinc, among others, including steroids for the elderly and asthmatic patients,” the lawmakers said in a joint statement.