What Are Monoclonal Antibodies? Eli Lilly Claims Drug Helps Mild-to-moderate COVID-19 Patients

The pharmaceutical company Eli Lilly has claimed a drug known as a monoclonal antibody helped COVID-19 patients get rid of symptoms faster than those on a placebo.

Eli Lilly said data collected from an ongoing Phase 2 clinical trial provided a proof of concept that giving LY-CoV555 to COVID-19 outpatients with a mild-to-moderate form of the disease also appeared to make them less likely to need hospital treatment, and cleared the virus faster.

The interim findings of the ongoing trial were not published in a scientific journal, meaning they have not been through the rigorous peer review process. The company said it plans to publish its results in a peer-reviewed journal.

What are monoclonal antibodies?

Antibodies are proteins that are part of the immune system. Made by white blood cells, they recognise pathogens, like viruses or bacteria, and stick to them. They ultimately help the body neutralize and clear invaders.

Monoclonal antibodies are lab-made molecules that mimic our natural antibodies. They are used to treat conditions such as cancer, rheumatoid arthritis, multiple sclerosis, cardiovascular disease, Crohn's disease, psoriasis, and ulcerative colitis.

The drugs are relatively expensive and difficult to manufacture.

What did Eli Lilly find?

The on-going trial involved 452 participants, 302 on the monoclonal antibody and 150 placebo patients. The company hopes to enroll 800 participants in total.

The rate of hospitalization and emergency room visits for coronavirus among participants was 1.7 percent for those who took LY-CoV555, and 6 percent for those who were given the placebo, amounting to a 72 percent reduction in risk in the participants, according to Eli Lilly.

The majority of patients, including those taking the placebo, had almost totally cleared the virus by day 11. But participants given a 2,800 mg dose of LY-CoV555 saw their viral levels drop by day three. The patients taking LY-CoV555 appeared to see their symptoms improve faster than those given the placebo.

No serious adverse side effects were reported, and the drug was well-tolerated, the team said.

"The results reinforce our conviction that neutralizing antibodies can help in the fight against COVID-19," Daniel Skovronsky, Lilly's chief scientific officer and president of Lilly Research Laboratories, said in a statement. "These interim data from the BLAZE-1 trial suggest that LY-CoV555, an antibody specifically directed against SARS-CoV-2, has a direct antiviral effect and may reduce COVID-related hospitalizations."

Experts not involved in the research welcomed the findings. Andrew Preston, an expert in microbial pathogenesis at the University of Bath in the U.K., told Newsweek the findings were positive but preliminary. "A treatment that helps to reduce the severity of COVID-19 disease is very welcome," he said.

Preston said: "The trial contained only small numbers of patients who progressed to more serious disease, as only 6 percent of the control group reached this endpoint. This suggests that the trial tested the treatment on those with relatively mild disease, or that other treatments administered to patients were effective at preventing disease progression. Other discussions of MAb [monoclonal antibody] therapy have focused on its use to treat the most ill patients, this has yet to be tested.

"Interestingly, only one dose proved to have significant effect and it was the middle dose, not the highest dose. It will be important to determine why the high dose was not effective, as it appears that giving a specific level of antibody is important and it's not clear if this level varies among individuals."

Myron Cohen, director of the Institute for Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill, told The New York Times the results were "really compelling" and the trial seemed to be rigorous.

Rajesh T. Gandhi, an infectious disease specialist at Massachusetts General Hospital, told the newspaper it was encouraging the drug appeared to lower levels of the virus in the respiratory tract. This could mean patients are less infectious, but would need to be confirmed in bigger trials. He said he wanted to see more detail from the study when it finished.

This article has been updated with comment from Andrew Preston.