One of the treatments President Donald Trump received soon after testing positive to COVID-19 was an experimental antibody cocktail from Regeneron.
The drug is so new that the federal Food and Drug Administration has not approved it yet for most hospitalized COVID-19 patients. Trump received Regeneron for COVID-19 under what’s known as a “compassionate use” request.
The key question now is whether Regeneron therapy for COVID-19 works. Doctors conducting clinical trials on the experimental drug in Colorado and elsewhere are working to answer that question now.
President Trump, Regeneron and COVID-19
The drug, called REGN-COV2, is well familiar to Dr. Thomas Campbell, a University of Colorado School of Medicine and UCHealth virologist and infectious-disease specialist. He’s leading the Colorado site in two multi-center clinical trials sponsored by Regeneron to understand REGEN-CoV2’s safety and effectiveness against COVID-19. While preliminary findings announced in a Sept. 29 press release from the company look promising, the drug’s effectiveness remains an open question, Campbell says.
The Regeneron clinical trials Campbell is conducting are among three trials related to Regeneron that are now underway at UCHealth University of Colorado Hospital on the Anschutz Medical Campus. Campbell’s studies focus on testing REGN-COV2 with outpatients as well as inpatients. A third study is considering the drug’s effectiveness in preventing the coronavirus.That one is being led locally by Dr. Eric Simoes, a CU School of Medicine pediatric infectious-disease specialist, and his colleague, Dr. Brian Montague, who focuses on infectious diseases in adults for UCHealth and the CU School of Medicine.
REGN-COV2 contains two monoclonal antibodies, REGN10933 and REGN10987. These are lab-engineered proteins that act like the infection fighters your body produces after being exposed to SARS-CoV-2 or taking an effective vaccine that mimics aspects of the virus. Regeneron researchers evaluated thousands of antibodies produced by people who had recovered from COVID-19 as well as by mice genetically engineered to have human immune systems. They winnowed that long list down to those two antibodies. Both bind to different parts of the SARS-CoV-2 spike proteins the coronavirus uses to unlock human cells and ultimately hijack cellular machinery to make untold copies of themselves. So doing, in theory, gums up the ability of the virus to replicate.
Regeneron results: So far, so good
The preliminary results Regeneron announced on Sept. 29 applied to 275 patients of the 2,100 people expected to be involved in the outpatient study (six of them have been at UCH, Campbell says). That study is comparing viral loads among those who received one-time REGN-COV2 infusions of 2.4 grams, 8 grams, or a placebo. The company reported that the drug sharply cut the amount of virus among those who got the drug; that patients with fewer natural coronavirus antibodies at the time they got the drug saw greater reductions in viral load than those with existing antibodies; and that the more virus a patient started with, the more impact the drug had in reducing viral load.
Campbell called the results “encouraging,” but cautioned that Regeneron had yet to publish detailed, peer-reviewed data.
“We don’t know if those measures have any clinical significance, bottom line,” he said. “You would think that they would, and you would think that they could correlate not only with getting people better faster by reducing the viral load in respiratory secretions but also that it would decrease the transmissibility – so reduce the infectiousness of the individual who has COVID and prevent spread to other people.”
Should the results stand up to peer review, the success of REGN-COV2 would be a strong tailwind for the roughly 70 teams pursuing lab-engineered antibodies as a COVID-19 therapy. These efforts have gotten much less attention than those related to vaccine development (Campbell is also leading the Colorado trial site of Moderna’s vaccine). But coronavirus-targeting antibody therapies, if successful, would represent major breakthroughs in taming the pandemic, particularly if they prove effective in bolstering patients’ immune systems enough to keep what might have been serious cases out of hospitals and the most serious cases out of intensive-care units.
Campbell’s two studies have involved nine patients so far, he says. It’s a number he hopes will grow, though he recognizes that, particularly with patients who have fallen ill with the coronavirus, participation can be a sacrifice
“It takes a lot of time and effort for people to participate in these studies, and oftentimes, the patients are sick and have to come in for a research visit that they wouldn’t necessarily have to do otherwise,” he said.