Benzinga | May 17, 2021 07:07AM EDT

Sanofi-GSK's COVID-19 Vaccine Candidate Reports Success In Mid-Stage Study

* Sanofi SA (NASDAQ: SNY) and its collaborating partner GlaxoSmithKline plc (NYSE: GSK) have reported "strong immune responses" in early tests of their COVID-19 vaccine, raising hopes it could join the fight against the pandemic.

* The firms are combining a Sanofi-developed antigen, which stimulates the production of germ-killing antibodies, with GSK's adjuvant technology, a substance that bolsters the immune response triggered by a vaccine.

* The experimental vaccine "achieved strong rates of neutralizing antibody responses, in line with those measured in people who have recovered from COVID-19, in all adult age groups in a Phase 2 study with 722 volunteers," it said in a statement.

* "A global pivotal Phase 3 study is expected to start in the coming weeks."

* The Phase 2 interim results showed 95% to 100% seroconversion following the second injection in all age groups (18 to 95 years old) across all doses, with acceptable tolerability and no safety concerns.

* A single dose generated high neutralizing antibody levels in participants with evidence of prior SARS-CoV-2 infection, suggesting strong potential for development as a booster vaccine.

* The company plans to initiate a global Phase 3 study with the 10?g dose in more than 35,000 adult participants.

* It will assess the efficacy of two vaccine formulations, including the D614 (Wuhan) and B.1.351 (South African) variants.

* In parallel, the companies intend to conduct booster studies with various variant formulations to assess if a lower vaccine dose generates a strong booster response regardless of the initial vaccine platform received.

* The vaccine's approval is expected in the fourth quarter of 2021, subject to regulations and Phase 3 outcome.

* Price Action: GSK shares are down 0.15% at $39.02, and SNY shares are up 0.42% are at $52.96 during the premarket session on the last check Monday.