Anglo-Swedish drugmaker AstraZeneca said on Tuesday a study of its monoclonal antibody treatment, AZD7442, did not meet the main goal of preventing symptomatic COVID-19 in people recently exposed to the novel coronavirus.

The company said the participants in the trial were unvaccinated adults older than 18 years with confirmed exposure to a person with the coronavirus within the past eight days.

AZD7442 reduced the risk of developing symptomatic COVID-19 by 33% compared to a placebo, which was not statistically significant, the company reported.

'While this trial did not meet the primary endpoint against symptomatic illness, we are encouraged by the protection seen in the PCR negative participants following treatment with AZD7442,' Mene Pangalos, AstraZeneca executive vice president, said in a statement.

AstraZeneca is also studying the treatment in a pre-exposed patients trial and for preventing more severe disease.

The monoclonal antibody therapy belongs to a class of drugs which mimic natural antibodies the body produces to fight off the infection.

Rivals Regeneron Pharmaceuticals Inc and Eli Lilly & Co have both developed monoclonal antibody therapies which have been authorised for use in the United States to treat patients infected with the virus.. The European Medicines Agency (EMA) has approved Regeneron's therapy and is reviewing similar drugs from Eli Lilly, Celltrion and one developed by GlaxoSmithKline and Vir Biotechnology Inc.

AstraZeneca in October enlisted Swiss contract manufacturer Lonza to produce the antibody drug in Portsmouth, New Hampshire, starting in the first half of 2021.

AZD7442 is being developed with support from the U.S. government. AstraZeneca in March announced a deal with the U.S. government to supply up to half a million doses of AZD7442. The company said on Tuesday it is now in talks with the U.S. government regarding next steps on the deal.