Sanofi, GSK COVID-19 vaccine rollout delayed on low immune response in older adults

French pharma major Sanofi and British multinational pharma company GSK have said their COVID-19 vaccines will not be ready before the end of 2021. The announcement came after interim results showed their vaccine candidate generated low immune response among older adults. "Sanofi and GSK announce a delay in their adjuvanted recombinant protein-based COVID-19 vaccine programme to improve immune response in the elderly," a statement by GSK said, adding the final rollout of its vaccine has now been delayed from mid-2021 to Q4 2021.

GSK said the phase 1/2 interim results showed an immune response comparable to patients who recovered from COVID-19 in adults aged 18 to 49 years.  "A recent challenge study in non-human primates performed with an improved antigen formulation demonstrated that the vaccine candidate could protect against lung pathology and lead to rapid viral clearance from the nasal passages and lungs, within 2 to 4 days. These results increase the company's confidence in the capacity of the adjuvanted recombinant platform to deliver a highly efficient vaccine for all adults," said the company.

However, there was an insufficient response in older adults, which means there's a need to refine the concentration of antigen to provide high-level immune response across all age groups, it said. The companies now plan a Phase 2b study with an improved antigen formulation to ensure high immune response among patients.

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The next study will start in February 2021, with the support from BARDA (Biomedical Advanced Research and Development Authority) as part of Operation Warp Speed, including a proposed comparison with an authorised COVID-19 vaccine, the British multinational pharmaceutical company said.

Notably, Sanofi's recombinant technology and GSK's pandemic adjuvant are established vaccine platforms that have proven successful against influenza. The recombinant technology offers the advantages of stability at temperatures used for routine vaccines, the ability to generate high and sustained immune responses, and the potential to prevent virus transmission.

"We have identified the path forward and remain confident and committed to bringing a safe and efficacious COVID-19 vaccine. Following these results and the latest encouraging new preclinical data, we will now work to further optimise our candidate to achieve this goal," said Thomas Triomphe, Executive Vice President and Head of Sanofi Pasteur, adding no single pharma company can make it alone and that the world needs more than one vaccine to fight the pandemic.

Roger Connor, President of GSK Vaccines, said the results of the study are not as they hoped but expressed confidence that with Sanofi, they will develop the vaccine with an improved antigen formulation to fight Covid-19.

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Notably, Pfizer, BioNTech, Moderna, and Russia's Sputnik V are the only vaccines that have claimed over 90 per cent efficacy of their respective candidates so far. While Russia had already rolled out Sputnik V for the masses in August, the recently announced data results on the efficacy of Moderna, Pfizer, and BioNTech's vaccines have also raised high hopes. Besides, Swedish drugmaker AstraZeneca and the University of Oxford's vaccine candidate, being developed along with India's Serum Institute, has also achieved 70 per cent efficacy during the preliminary analysis of its COVID-19 trial participants.

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