New Delhi :The national drugs regulator has granted approval to pharma majors Sanofi and GSK to conduct phase 3 clinical trials of their Covid-19 vaccine candidate in India, the companies announced in a joint statement on Thursday.It will be a bridging trial to assess the safety, efficacy, and immunogenicity of their adjuvanted recombinant-protein Covid-19 vaccine candidate as part of the global, randomised, double-blind phase 3 study with over 35,000 volunteers aged above 18 across the US, Asia, Africa, and Latin America.

“The primary endpoint of the study is the prevention of symptomatic COVID-19 in SARSCoV-2 naïve adults, with secondary endpoints being the prevention of severe COVID-19 disease and prevention of asymptomatic infection,” said the statement. According to the companies, the global interim phase 2 results have shown that the vaccine candidate achieved high rates of neutralizing antibody responses in all adult age groups, with 95 to 100% seroconversion rates. After a single injection, high neutralizing antibody levels were also generated in participants with evidence of prior SARS-CoV-2 infection, suggesting strong potential for development as a booster vaccine.

In a two-stage approach, the study will initially investigate the efficacy of a vaccine formulation targeting the original virus strain (D.614), while a second stage will evaluate a second formulation targeting the Beta variant (B.1.351).

The design of the phase 3 study, conducted across a broad diversity of geographies, also allows evaluation of the efficacy of the candidate against a variety of circulating variants.

Sanofi and GSK will also run clinical studies to assess the ability of the adjuvanted recombinant-protein Covid-19 vaccine candidate to generate a strong booster response regardless of the type of vaccine initially received.

“India is participating in Sanofi Pasteur’s pivotal Phase 3 study… we should soon begin enrolment of study participants in the country,” said Annapurna Das, country head, Sanofi Pasteur India.