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COVID-19 Antibody Cocktail Reduces Viral Levels, Regeneron Says
The COVID-19 antibody cocktail, a combination of two monoclonal antibodies designed to block infectivity of SARS-COV-2, was most effective in patients who had not mounted their own immune response, initial clinical trial data shows.
Regeneron Pharmaceuticals recently announced that its COVID-19 antibody cocktail reduced viral load and alleviated symptoms in non-hospitalized coronavirus patients in a Phase 1/2/3 clinical trial.
Specifically, the antibody, REGN-COV2, rapidly reduced viral load through Day 7 in patients without an antibody presence (seronegative).
The mean time-weighted-average change from baseline viral load through Day 7 in the seronegative group was a 0.60 log10 milliliters greater reduction in patients treated with high dose compared to a placebo, a Regeneron spokesperson said. Patients treated with a low dose saw a 0.51 log10 milliliters greater reduction compared to a placebo.
These findings suggest that REGN-COV2 could provide a therapeutic substitute for the naturally-occurring immune response, said George D. Yancopoulos, MD, PhD, president and chief scientific officer of Regeneron.
"After months of incredibly hard work by our talented team, we are extremely gratified to see that Regeneron's antibody cocktail REGN-COV2 rapidly reduced viral load and associated symptoms in infected COVID-19 patients,” he said.
“In addition to having positive implications for REGN-COV2 trials and those of other antibody therapies, these data also support the promise of vaccines targeting the SARS-CoV-2 spike protein."
The randomized, ongoing, double-blind clinical trial enrolled 275 patients who had either mounted their own effective immune response against SARS-COV-2 or whose immune response was not yet adequate.
Patients were identified by the presence (seropositive) or absence (seronegative) of SARS-COV-2 antibodies or by high viral loads at baseline and received a high dose of REGN-COV2 (8 grams), a low dose (2.4 grams), or a placebo.
Approximately 45 percent of patients were seropositive, 41 percent were seronegative, and 14 percent were categorized as "other,” researchers said.
Viral load is the amount of COVID-19 that is present in an infected individual’s blood.
For seronegative patients, median time to symptom alleviation was 13 days for the placebo group, eight days for the high-dose group, and six days for the low-dose group.
Overall, seropositive patients had significantly lower levels of virus at baseline and achieved viral loads nearing lowest levels quantifiable, while seronegative patients had notably higher levels at baseline and cleared the virus more slowly with no treatment.
Researchers also found that patients with higher baseline viral levels had correspondingly greater reductions in viral load at Day 7 with REGN-COV2 treatment.
Specifically, they found a 50 to 60 percent reduction in viral load at Day 7 compared to placebo specifically in patients with baseline viral levels higher than 0.93 milliliters.
In patients with a viral load higher than 1.79 milliliters, there was a nearly 99 percent reduction compared to placebo.
The antibody showed positive trends in reducing medical visits as well.
Approximately 10 to 12 medically-attended visits were from patients in the seronegative group. Specifically, 15.2 percent of placebo-treated patients, 7.7 percent of patients treated with high dose, and 4.9 percent of patients treated with low dose required additional medical visits.
There were also no notable adverse events in the trial, and no deaths occurred.
REGN-COV2 is a combination of two monoclonal antibodies designed specifically to block infectivity of SARS-COV-2, Regeneron said.
The trial is part of a larger program of over 2,000 individuals that study REGN-COV2 for the treatment of hospitalized patients and will continue to uncover the effect of adding REGN-COV2 to usual standard care, compared to adding placebo.
The program also studies the prevention of infection in individuals that have been exposed to COVID-19 patients, a Regeneron spokesperson said in the announcement.
The COVID-19 antibody cocktail recently gained attention after President Trump reported taking the treatment while fighting the virus earlier this month. The president touted the treatment as a “cure” for the novel coronavirus in a video last week.
Regeneron has submitted an application to the FDA for emergency use authorization of its COVID-19 antibody cocktail, according to national news sources.
Eli Lilly also applied for emergency use authorization of a similar COVID-19 antibody therapy, which was also touted by President Trump in the video last week. Early clinical data trial has shown the experimental treatment to be effective at reduce viral levels.
