When US President Donald Trump was ill with COVID-19, his physicians administered a bevy of medications — some proven, others experimental. But there is one that the president has hailed as a “cure”: a cocktail of coronavirus antibodies produced by Regeneron Pharmaceuticals in Tarrytown, New York.
The ‘curative’ power of this antibody treatment has yet to be proven. Although it has shown promise in small, early studies in people with mild COVID-19 symptoms, large clinical trials have not yet been completed. Meanwhile, researchers are already designing more-advanced antibody treatments that could be cheaper, easier to produce and more potent.
“What you really want is something that is so amazingly potent that you need barely any,” says biochemist Pamela Björkman of the California Institute of Technology in Pasadena. “You want to be able to give it to everybody in the house or the hospital or the school or the meat-packing plant that’s been exposed.”
Antibodies are a key component of the body’s natural immune response to SARS-CoV-2, and researchers have been racing to develop therapies that harness their ability to directly bind to viral proteins and prevent the virus from replicating. One way to do this is by using blood plasma from people who are recovering from COVID-19 to transfer the antibodies that they have produced to someone else. Another is to manufacture and mass-produce specific antibodies against the virus that could supplement the body’s immune response. This approach has proven successful against other diseases: on 14 October, the US Food and Drug Administration (FDA) approved a cocktail of three specific antibodies, also produced by Regeneron, as a treatment against the Ebola virus, after it was shown to reduce deaths from the virus in the Democratic Republic of Congo.
Early trial success
Regeneron and Eli Lilly in Indianapolis, Indiana, now lead the race in developing antibody treatments against COVID-19. Each is testing its own proprietary antibodies and has applied for an Emergency Use Authorization from the FDA on the back of promising early studies. Eli Lilly’s first antibody therapy reduced visits to the hospital, from 6% in the placebo group to 1.7% in those who received the drug; Regeneron’s combination of 2 antibodies reduced symptoms and viral loads.
The main hope is that antibody therapies could stop mild COVID-19 from becoming severe. There is less optimism that the treatments will be game-changing for severe COVID-19 cases — when damage is caused by not only the virus, but also the body’s immune response to it. “I can’t imagine how excited I would be if these drugs were available and proved reliable,” says infectious-disease physician Myron Cohen of the University of North Carolina at Chapel Hill.
