Regeneron Pharmaceuticals said on Monday that the Covid-19 antibody drug combination it is developing both prevented and treated the disease in rhesus macaques and hamsters, adding to hope that it might work for people.
The US biotech company said in the animal study, which has not yet been peer reviewed, that the cocktail of two monoclonal antibodies was able to “almost completely block establishment of virus infection.”
Regeneron said the cocktail was also able to minimize infection in a second study in which animals were infected with a much higher level of the virus. The prophylactic effect was greatly diminished with a lower dose of the drug, the company said.
It said the results matched or exceeded effects recently shown in animal studies of vaccine candidates.
Effective treatments and vaccines are seen as essential to halting a pandemic that has claimed more than 690 000 lives worldwide.
The infected animals treated with the antibodies cleared the virus faster than those given a placebo, the company said.
The lead researchers said the data suggests the therapy may offer clinical benefit in both prevention and treatment of Covid-19. They also said the animals did not show any signs of increased viral load or worsening of pathology after treatment, an important safety signal that suggests it will not worsen symptoms in humans.
The studies were conducted on a total of 36 rhesus macaques and 50 hamsters. Positive results in animals are no guarantee of success in humans.
Regeneron has already started late-stage clinical trials in humans to assess the antibody treatment’s ability to prevent and treat Covid-19.
The company signed a $450-million contract with the US government as part of its Operation Warp Speed program to provide the United States with the treatment if it succeeds.
Monoclonal antibodies are among the most widely used biotechnology medicines. Eli Lilly and Co and other drugmakers are testing similar treatments against Covid-19.