Ocugen, the US partner of vaccine maker Bharat Biotech, announced “positive” results from the Phase 2/3, observer-blind, immuno-bridging, and broadening study of its Covid-19 vaccine candidate, Covaxin, in the US.

Covaxin, a whole-virion inactivated Covid19 investigational vaccine candidate of Bharat Biotech uses the same vero cell manufacturing platform that has been used in the production of polio vaccines for decades.

Broader immune response

Covaxin, an inactivated virus vaccine adjuvanted with a TLR7/8 agonist, has been demonstrated in clinical trials to generate a broader immune response against the whole virus, covering important antigens such as S-protein, RBD, and N-protein, whereas currently approved vaccines in the US target only the S-protein antigen.

Additionally, in contrast to other inactivated vaccines, clinical trials have demonstrated that the TLR7/8 agonist adjuvant in Covaxin generates a Th1-biased immune response that induces robust long-term memory B- and T-cell responses.

“The successful completion of this study represents an important milestone to the ongoing management of Covid-19,” Shankar Musunuri, Chairman, Chief Executive Officer, and Co-Founder, Ocugen, said in a release. 

“Given that a portion of the public remains hesitant to receive mRNA vaccines, this investigational Covid-19 vaccine candidate, which relies on a well-established approach to vaccine development and manufacturing, may provide an important additional vaccine option.”

This study enrolled 419 US adult participants who were randomised 1:1 to receive two doses of Covaxin or a placebo, 28 days apart. Blinded safety results and preliminary unblinded immunogenicity results are available through Day 56, one month following the second vaccination.

Immunogenicity results from Covaxin-vaccinated participants in the US were compared with results from Covaxin-vaccinated participants in the Bharat Biotech International Limited (Bharat Biotech)-sponsored Phase 3 study in India.

Approximately 24 per cent of tested participants in the US were vaccine-nave, while all participants in the Bharat Biotech Phase 3 study were vaccine-naïve. Immune responses were adjusted for differences between the U.S. and Indian cohorts in baseline neutralising antibodies, body mass index, gender, and age. 

The top-line data from the immuno-bridging and broadening study will be critical to supporting Oxygen’s future plans for the development of Covaxin in the US.

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