Monoclonal Antibody Treatments

Written by Alice Han, Edited by Sami Morse


Produced en-masse by B cells, one of the most potent cells in our immune system’s arsenal, immunoglobulins (you may know them as antibodies) play an integral role in the body’s defense against invading germs. They bind to specific antigens, such as proteins vital to pathogens, dangerous toxins, or other targets that may cause harm to our bodies, and make it easier for our immune system to recognize invading cells, render said cells ineffective, and promote clearance of infection.

As both the understanding of antibody interactions and available biotechnology have advanced, scientists have learned how to construct antibodies that can be used in a clinical setting. Over the past few years, antibodies have been used to solve an increasing range of conditions, making up seven of the ten best-selling drugs in 2019.

In June 2020, the pharmaceutical company Eli Lilly launched the first human study of a SARS-CoV-2 antibody treatment with the drug Bamlanivimab, or LY-CoV555. Though the preliminary data has not yet been released to the public, Bamlanivimab was deemed safe, and advanced to phase II clinical trials. On October 28, preliminary data from phase II was released in the New England Journal of Medicine, determining the optimal dosage for the drug. In this double-blind trial, researchers gave participants either a placebo, a 700 mg dose, a 2800 mg dose, or a 7000 mg dose. The group that received a 2800 mg dose had higher clearance of the virus on day 7 (though there remains uncertainty regarding the clinical significance of this), and decreased symptom severity during early onset of the disease; additionally, participants that received LY-CoV555 across all dosages had significantly lower hospitalization rates overall and in high-risk groups, specifically.

Given the encouraging results of this Phase II trial, the U.S. Food and Drug Administration issued an Emergency Use Authorization for Bamlanivimab on November 9, 2020. This means that LY-CoV555 is authorized to be administered to patients 12 years or older, that weigh at least 88 pounds, who are SARS-CoV-2 positive and are at risk for developing severe COVID-19 or hospitalization.


The United States government purchased 300,000 vials of this antibody treatment in late October 2020, and 650,000 additional vials on December 2nd. In August of 2020, Eli Lilly launched phase III trials for the prevention of SARS-CoV-2 in long-term care facilities, which are still being conducted, with a primary completion date of March 8, 2021. The study will not be finished until late June, thus no results have been published yet. They hope their efforts will significantly contribute to alleviating the SARS-CoV-2 pandemic, and play a vital role in saving lives.


Aside from Bamlanivimab, more than 70 other monoclonal antibody treatments for SARS-CoV-2 are now in development. As vaccines continue to roll out across the world, these antibody treatments will still play a vital role in pandemic response: vaccines will curb SARS-CoV-2 contraction, while antibody treatment will help the prospects of patients who have already been infected with the virus. The promise that this treatment and others show is significant; LY-Co555 has the potential to save patients from severe infection, and will be a vital tool for physicians across the nation.

Results from ongoing research and the current understanding of COVID-19 are constantly evolving. This post contains information that was last updated on April 8, 2021.

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