Washington, Nov 9 (IANS): A single shot of Regeneron Pharmaceuticals's antibody cocktail reduced the risk of Covid-19 by 81.6 per cent for two to eight months, according to results of the phase-3 trials presented by the company.

Casirivimab and Imdevimab injection is a cocktail of two monoclonal antibodies and was designed specifically to block infectivity of SARS-CoV-2, the virus that causes Covid-19. The monoclonal antibodies are produced by recombinant DNA technology.

During the eight-month assessment period there were zero hospitalisations for Covid-19 and deaths in the REGEN-COV group, but six such incidents were recorded in the placebo group, the company said.

"These results demonstrate that REGEN-COV has the potential to provide long-lasting immunity from SARS-CoV-2 infection," said Myron S. Cohen, who leads monoclonal antibody efforts for the US National Institutes of Health-sponsored Covid Prevention Network.

The findings are particularly important to those who do not respond to Covid-19 vaccines including people who are immunocompromised, the company said.

The therapy had previously shown an 81.4 per cent risk reduction during the first month after administration.

Besides providing long-term protection against Covid-19, the trial also showed that the drug cocktail prevented "including times of particularly high risk from household exposure", the company said.

REGEN-COV has not been approved by the FDA, but is currently authorised in the US for the treatment and post-exposure prophylaxis in certain high risk individuals.

To increase global supply of the antibody cocktail, Regeneron has collaborated with Roche including in India.

Emergency or temporary pandemic use authorisations are currently in place in more than 40 countries, including India, the US, Switzerland and Canada, while the antibody cocktail is fully approved in Japan and conditionally approved in the UK.