U.S. pauses Eli Lilly’s trial of a coronavirus antibody treatment over safety concerns

Eli Lilly’s late-stage trial of its leading monoclonal antibody treatment for the coronavirus has been paused by U.S. health regulators over potential safety concerns, the company confirmed to CNBC on Tuesday.

“Safety is of the utmost importance to Lilly. We are aware that, out of an abundance of caution, the ACTIV-3 independent data safety monitoring board (DSMB) has recommended a pause in enrollment,” a spokeswoman Molly McCully told CNBC. “Lilly is supportive of the decision by the independent (Data Safety Monitoring Board) to cautiously ensure the safety of the patients participating in this study.

The ACTIV-3 trial is designed to test a monoclonal antibody developed by Eli Lilly in combination with remdesivir, an anti-viral with emergency use authorization for the virus. It’s one of several ongoing trials that are part of the National Institute of Health’s “Activ” program, which is designed to accelerate the development of Covid-19 vaccines and treatments. It is also backed by Operation Warp Speed, the Trump administration’s effort to manufacturer and distribute vaccines to fight Covid-19.

Eli Lilly’s drug is part of a class of treatments known as monoclonal antibodies, which are made to act as immune cells that scientists hope can fight the virus. The treatment was developed using a blood sample from one of the first U.S. patients who recovered from Covid-19. AstraZeneca and Regeneron, among other companies, are also working on so-called antibody treatments.

Monoclonal antibody treatments hit the headlines this month after news broke that President Donald Trump received an antibody cocktail from Regeneron Pharmaceuticals. As Trump’s health improved, he touted it it as a “cure.” But Regeneron’s CEO Leonard Schleifer has stressed that more testing is required.

No details regarding Eli Lilly’s safety concern are yet known.

“When scientists test promising treatments, sometimes unexpected side effects occur,” said Jeremy Faust, a health policy expert and emergency medicine doctor at Brigham and Women’s Health.

Faust was part of the group of scientists that first reported the news via the research site Brief19.

“When only a small number of patients have received a compound, it’s hard to tell what’s a real problem and what is noise,” he told CNBC. “That’s why patience and prudence are always warranted before doling out experimental treatments.”