Monoclonal antibodies show promise in treating mild-moderate COVID-19; trial reduces hospitalization: Lilly

Multiple drug companies are actively researching monoclonal antibodies for treatment of COVID-19. Lilly announced success (see this Medscape article from September 17) in reducing hospitalizations with one of its antibodies in clinical trials. The trials, in 302 patients with mild to moderate symptoms, reduced hospital stays or emergency room visits from 6% (with placebo) to 1.7% (five patients) of the treated group.

Monoclonal antibodies are given in a single dose intravenously, and one shot delivers antibodies that last about a month. The shots could be used either for treatment, early or late during the disease, or prevention. It is not yet known when during infection would be the best time to administer the shot.

Monoclonal antibodies are derived from the serum of patients who are convalescing after acute viral infection. Each individual type of antibody is produced by a single immune cell which can be cloned– thus, monoclonal. The antibody is directed against a specific part of the virus, usually the spike protein with which it attaches to an endothelial cell during infection.

Once the monoclonal antibody is identified (separated from the large group of different antibodies circulating in a recovering patient’s serum) it can be produced by a specific segment of DNA. That DNA segment is transferred into another type of cell which can be cultured in a “broth” that nourishes the cells– in this case, a cell from an animal embryo.

Large numbers of these cells are cloned and grown over several months in a tank. The antibody protein is then purified from the broth, sterilized, and put into cold storage. This process is time, labor, and money-intensive.

Sufficient antibody of one type for about 100,000 treatments has been collected in this way. If the continued trials with this antibody are successful, Lilly will seek approval from the Food and Drug Administration (FDA) to market the antibody for clinical use.

Regeneron Pharmaceuticals and Vir Biotechnology, among others, are also working on additional monoclonal antibodies for use in COVID-19. The treatments are likely to be very expensive because of the complex and lengthy manufacturing process.