Sanofi and GSK announce a delay in their adjuvanted recombinant protein-based COVID-19 vaccine program to improve immune response in the elderly.

Sanofi and GSK announce a delay in their adjuvanted recombinant protein-based COVID-19 vaccine program to improve immune response in older adults. Phase 1/II study interim results showed an immune response comparable to patients who recovered from COVID-19 in adults aged 18 to 49 years, but a low immune response in older adults likely due to an insufficient concentration of the antigen 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 Companies confidence in the capacity of the adjuvanted recombinant platform to deliver a highly efficient vaccine for all adults. Roger Connor, President of GSK Vaccines added: “The results of the study are not as we hoped. Based on previous experience and other collaborations, we are confident that GSK’s pandemic adjuvant system, when coupled with a COVID-19 antigen, can elicit a robust immune response with an acceptable reactogenicity profile. It is also clear that multiple vaccines will be needed to contain the pandemic. Our aim now is to work closely with our partner Sanofi to develop this vaccine, with an improved antigen formulation, for it to make a meaningful contribution to preventing COVID-19.” The Companies plan a Phase IIb study expected to start in February 2021 with support from the Biomedical Advanced Research and Development Authority (BARDA), part of the HHS Office of the Assistant Secretary for Preparedness and Response (ASPR) under contract W15QKN-16-9-1002. The study will include a proposed comparison with an authorized COVID-19 vaccine. If data are positive, a global Phase III study could start in Q2 2021. Positive results from this study would lead to regulatory submissions in the second half of 2021, hence delaying the vaccine’s potential availability from mid-2021 to Q4 2021. the Phase 1/II study : The interim Phase 1/II results showed a level of neutralizing antibody titers after two doses comparable to sera from patients who recovered from COVID-19, a balanced cellular response in adults aged 18 to 49 years, but insufficient neutralizing antibody titers in adults over the age of 50. The candidate showed transient but higher than expected levels of reactogenicity likely due to the suboptimal antigen formulation, with no serious adverse events related to the vaccine candidate. The most favorable results were observed in the group which tested the highest antigen concentration, combined with the GSK adjuvant, showing neutralization titers in 88% of participants. Seroconversion was observed in 89.6% of the 18 to 49 age group; 85% in the >50 age group; and 62.5% in the >60 age group.