Eli Lilly pauses COVID-19 antibody trial, citing potential safety concern

The Eli Lilly sign in front of its corporate headquarters in Indianapolis
Eli Lilly & Co. corporate headquarters in Indianapolis.
(Darron Cummings / Associated Press)

Eli Lilly & Co. said enrollment of participants in a clinical trial of its antibody treatment for COVID-19 has been paused due to a potential safety concern.

The independent Data and Safety Monitoring Board recommended pausing enrollment in the U.S. government-sponsored trial, a company spokeswoman said in an emailed statement. The company didn’t provide information about what caused the panel to recommend the stoppage.

“Lilly is supportive of the decision by the independent DSMB to cautiously ensure the safety of the patients participating in this study,” said spokeswoman Kathryn Beiser.


Indianapolis-based Lilly is one of several companies developing monoclonal antibody therapies, which can potentially aid those with early COVID-19 symptoms from developing severe cases and are also being studied as a prophylaxis. Such therapies are seen by pharmaceutical executives and government health officials as a viable bridge to a vaccine.

The class of treatments was spotlighted when President Trump received a similar therapy developed by Regeneron after he was infected with COVID-19. Trump has since called that therapy a “cure” and said he would push for it and similar treatments to get approval for use in the United States.

Shares of Eli Lilly declined as much as 3.3% in afternoon trading Tuesday.

The action came less than 24 hours after Johnson & Johnson said it had paused a late-stage study of its COVID-19 vaccine while the company investigated whether a study participant’s “unexplained illness” was related to the shot.

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In August, the U.S. National Institutes of Health began testing Lilly’s monoclonal antibody LY-CoV555 in hospitalized COVID-19 patients. The 300-participant trial, known as ACTIV-3, will also treat patients in both the placebo arm and antibody arm with the Gilead Sciences antiviral drug remdesivir, which is considered to be a standard of care.

News of the pause in the ACTIV-3 trial was first reported by the New York Times, citing emails that government officials sent to researchers at testing sites.

Such pauses for large clinical trials don’t necessarily mean anything is wrong with the treatment. A final decision must be made by the monitoring board before any future action is taken.


Both Lilly and Regeneron have approached the U.S. Food and Drug Administration seeking emergency-use authorization for their treatments. Lilly is seeking authorization for high-risk patients recently diagnosed with mild to moderate COVID-19, based on promising data reported last month from a different trial, known as BLAZE-1.

Lilly serves as the primary sponsor on that trial, collaborating with its co-developer on the LY-CoV555 therapy, Canadian biotech company AbCellera Biologics. It’s also testing an antibody cocktail. The BLAZE-1 trial is testing the monotherapy and the combination therapy in patients with early symptoms of COVID-19 who have not been hospitalized. It is unclear whether the pause in the NIH-sponsored study will impact Lilly’s other ongoing clinical trials.

Preliminary data from both Lilly and Regeneron have been largely positive, suggesting their drugs have the ability to lower the amount of virus in the body.