Two COVID-19 Outpatient Antibody Drugs Show Encouraging Results

Marcia Frellick

October 29, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Two COVID-19 antibody treatments, one developed by Regeneron and the other by Eli Lilly, show promise in the outpatient setting in results released on Wednesday.

Regeneron, in a randomized, double-blind trial, is assessing the effect of adding its investigational antibody cocktail REGN-COV2 to usual standard of care in comparison with adding placebo to standard of care. A descriptive analysis from the first 275 patients was previously reported. The data described Wednesday, which involve an additional 524 patients, show that the trial met all of the first nine endpoints.

Regeneron announced prospective results from its phase 2/3 trial showing REGN-COV2 significantly reduced viral load and patient medical visits, which included hospitalizations, visits to an emergency department, visits for urgent care, and/or physician office/telemedicine visits.

Interest in the cocktail spiked after President Donald Trump extolled its benefits after it was used in his own COVID-19 treatment earlier this month.

Trump received the highest dose of the drug, 8 g, but, according to a Regeneron news release announcing the latest findings, "results showed no significant difference in virologic or clinical efficacy between the REGN-COV2 high dose (8 grams) and low dose (2.4 grams)."

The company described further results of the industry-funded study in the release: "On the primary endpoint, the average daily change in viral load through day 7 (mean time-weighted average change from baseline) in patients with high viral load (defined as greater than107 copies/mL) was a 0.68 log10 copies/mL greater reduction with REGN-COV2 compared to placebo (combined dose groups; p<0.0001). There was a 1.08 log greater reduction with REGN-COV2 treatment by day 5, which corresponds to REGN-COV2 patients having, on average, a greater than 10-fold reduction in viral load, compared to placebo."

The treatment appears to be most effective in patients most at risk, whether because of high viral load, ineffective baseline antibody immune response, or preexisting conditions, according to the researchers.

According to the press release, these results have not been peer reviewed but have been submitted to the US Food and Drug Administration, which is reviewing a potential emergency use authorization for the treatment in high-risk adults with mild to moderate COVID-19.

Operation Warp Speed, the Trump administration's treatment and vaccine program, contracted in July with Regeneron for up to 300,000 doses of its antibody cocktail.

Lilly Treatment Shows Drop in Hospitalizations, Symptoms

Another treatment, also given in the outpatient setting, shows promise as well.

Patients recently diagnosed with mild to moderate COVID-19 who received Eli Lilly's antibody treatment LY-CoV555 had fewer hospitalizations and symptoms compared with a group that received placebo, an interim analysis of a phase 2 trial indicates.

Peter Chen, MD, with the Department of Medicine, Women's Guild Lung Institute at Cedars-Sinai Medical Center, Los Angeles, California, and colleagues found that the most profound effects were in the high-risk groups.

The interim findings of the BLAZE-1 study, which was funded by Eli Lilly, were published online October 28 in The New England Journal of Medicine.

Researchers randomly assigned 452 patients to receive an intravenous infusion of LY-CoV555 in one of three doses (700 mg, 2800 mg, or 7000 mg) or placebo.

In the interim analysis, the researchers found that for the entire population, more than 99.97% of viral RNA was eliminated.

For patients who received the 2800-mg dose, the difference from placebo in the decrease from baseline was −0.53 (95% CI, −0.98 to −0.08; P = .02), for a log viral load that was lower by a factor of 3.4. Benefit over placebo was not significant with the other doses.

At day 29, according to the investigators, the percentage of patients hospitalized with COVID-19 was 1.6% (5 of 309 patients) in the treatment group compared with 6.3% (9 of 143 patients) in the placebo group.

Data indicate that the safety profile was similar whether patients received the active treatment or placebo.

"If these results are confirmed in additional analyses in this trial, LY-CoV555 could become a useful treatment for emergency use in patients with recently diagnosed Covid-19," the authors write.

Deborah Fuller, PhD, professor in the Department of Microbiology at the University of Washington School of Medicine in Seattle, told Medscape Medical News the findings are "exciting" but only part of the treatment solution.

"What's remarkable about these two studies and others I’ve seen," she said, "is how consistent they are in terms of the window of time they will be effective, and that’s because they are just targeting the virus itself. They do not have an effect on the inflammation unless they stop the replication early enough.”

The treatments are effective when they are given near the time of diagnosis, she pointed out.

"Once the virus has started that inflammatory cascade in your body, then that train has left the station and you have to deal with the inflammation," Fuller said.

She says future treatments will likely have to include both the antiviral and anti-inflammatory properties, and physicians will have to assess what's best, given the stage of the the patient's disease.

The trial of REGN-COV2 is funded by Regeneron. The BLAZE-1 study is funded by Eli Lilly. Many of the authors have financial ties to Eli Lilly. Fuller has disclosed no relevant financial relationships.

N Engl J Med. Published online October 28, 2020. Full text

October 30, 2020 — Editor's note: This article has been updated to include an interview with an independent commentator.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune and and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick.

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