An experimental COVID-19 vaccine developed by Sanofi and GlaxoSmithKline showed a robust immune response in early-stage clinical trial results, enabling the partners to move to a phase 3 trial.
The drugmakers were forced to restart their trial last December when the vaccine showed a low immune response in older adults. Now, phase 2 interim results showed 95% to 100% seroconversion following a second injection in all age groups and across all doses, with acceptable tolerability and no safety concerns.
After a single injection, high neutralizing antibody levels were generated in participants with evidence of prior SARS-CoV-2 infection, suggesting strong potential for development as a booster vaccine.
"We are analyzing this further as it may suggest our vaccine could serve as a potential booster, regardless of what vaccine someone may have received (beforehand)," Su-Peing Ng, Sanofi's global head of medical for vaccines, told reporters.
GSK and Sanofi's vaccine candidate uses the same technology as one of Sanofi's seasonal influenza vaccines. It will be coupled with an adjuvat, made by GSK.
Based on these positive phase 2 interim results, the companies plan to initiate a global phase 3, randomized, double-blind study with the 10µg dose, in combination with GSK’s pandemic adjuvant, in the coming weeks. This trial is expected to enroll more than 35,000 adult participants from a broad range of countries and will assess the efficacy of two vaccine formulations including the D614 (Wuhan) and B.1.351 (South African) variants
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