The European Medicines Agency said Tuesday it had started a "rolling review" of France's Sanofi coronavirus jab, which could lead to authorisation for use in the European Union.
"EMA will assess the compliance of Vidprevtyn with the usual EU standards for effectiveness, safety and quality," the agency said.
The Sanofi drug, developed with British firm GSK, joins four others on the EMA's review list, including Russia's Sputnik V and China's Sinovac.
Unlike mRNA vaccines, which need to be stored at ultra-cold temperatures, the Sanofi jab can be kept closer to room temperature, potentially helping the rollout.
The jab would require two doses, like most other vaccines on the market.
It combines 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.
Sanofi and GSK said in May that they would launch final trials after finding their drug "achieved strong rates of neutralising antibody responses" in Phase 2 clinical trials.
The EMA said its decision to start the review was based on preliminary results that "suggest that the vaccine triggers the production of antibodies that target SARS-CoV-2, the virus that causes COVID-19, and may help protect against the disease."
"EMA will evaluate data as they become available to decide if the benefits outweigh the risks," said the agency, adding that it could not give a timeline for the review.
The four vaccines with EMA authorisation in the EU are Pfizer-BioNTech, Moderna, AstraZeneca and Johnson & Johnson.