Covid-19: The National Health Surveillance Agency (Anvisa) authorized the start of phase 3 clinical studies with the monoclonal antibody leronlimab against covid-19. The authorization was announced this Monday (22) by Biomm, the company responsible for marketing the substance in Brazil.
The study will be led by the Academic Research Organization (ARO) of the Hospital Israelita Albert Einstein in 35 Brazilian research centers with 612 people hospitalized for infections caused by the coronavirus and in need of oxygen support. The goal is to prevent the worsening of symptoms in patients and avoid the use of intubation.
There is still no date set for the start of clinical trials, which depend on the importation of the drug, produced by the CytoDyn company in the United States. The drug is considered of public interest for the prevention or treatment of covid-19 by the Food & Drug Administration (FDA), a US agency similar to Anvisa.
What are monoclonal antibodies?
One of the ways in which the body’s immune system attacks foreign substances, such as viruses, bacteria and cancer, is by making a large number of antibodies, capable of attaching to a foreign substance, also known as an antigen. Once turned on, the antibodies can force other parts of the immune system to destroy cells that contain the foreign substance.
With the development of biotechnology, researchers were able to create proteins that specifically target a certain antigen, as found in cancer cells or in the coronavirus. These laboratory-created proteins, which mimic the immune system’s ability to fight specific antigens, are called monoclonal antibodies.
How does leronlimab work
Leronlimab is an experimental drug that has been studied to treat cancer and HIV infections. With the covid-19 pandemic, the drug began to be tested against Sars-CoV-2 as well.
The drug works to prevent an excessive immune system response in infected patients, known as a “cytokine storm,” when the body produces an excessive level of inflammatory cytokines. The storm is considered by scientists as the probable cause of the worsening of cases of patients with covid-19, which can lead to death.
Leronlimab targets the immune receptor CCR5, a protein located on the surface of a variety of cells, including white blood cells and cancer cells. In white blood cells, CCR5 acts as a receptor for chemical attractants called chemokines, a family of small cytokines. By blocking the receptor, the drug prevents viruses or cancer cells from harming healthy cells.
CytoDyn has conducted two separate clinical trials investigating leronlimab for the treatment of covid-19 in the United States. Although it does not usually release preliminary data on unapproved substances, the FDA reported in May 2021 that the available data does not indicate a clinical benefit of using the drug in infections caused by the new coronavirus.
A smaller trial sought to understand the drug’s effectiveness in 86 patients with mild to moderate infections, however, there was no observed effect of the drug on the primary endpoint of the study or any of the secondary endpoints.
A larger study, which included 394 patients with severe symptoms of respiratory disease associated with covid-19, also did not show any effect of the drug on mortality or in reducing the mean length of hospital stay in the analyzed group.