A single dose of lambda interferons has halved the risk of hospitalizations for SARS-CoV-2 infection in clinical trials. The rate of reduction even reached 89% in unvaccinated people. Update on this promising new treatment.
The relief of Paxlovid (Pfizer’s pill against Covid-19) has arrived, but without its drawbacks. On the one hand, Pfizer’s drug requires taking six tablets a day for five days, and its composition can interfere with the metabolism of many other drugs. On the other hand, the new antiviral drug developed by researchers at Stanford Medicine also makes it possible to reduce the number of hospitalizations linked to Covid-19, but in a single injection.
The advanced trial (phase 3) was conducted in Brazil and Canada on almost 2,000 adults, 85% of whom were vaccinated against the virus. To be included, patients had to test positive on a rapid antigen test and receive treatment or a placebo within seven days of showing symptoms of Covid-19. The results are published in the New England Journal of Medicine.
Use of interferons
The treatment called “PEG-lambda” is a synthetic version of interferon lambda, a protein that infected cells secrete as a first line of defense against viral infection, innately. Viruses have evolved ways of stopping the production of interferons in the cells they infect. However, they cannot suppress interferon receptors or prevent injected interferons from binding to these receptors and triggering potent antiviral activity. Although there are several types of interferons – such as alpha, whose receptors are abundant on the surface of the cells of many body tissues – the receptors for lambda interferon are mainly limited to the walls of the lungs, respiratory tracts and intestine (ideal for Covid-19), which makes it less toxic.
Study participants were divided into two groups: approximately 930 received a single subcutaneous injection of PEG-lambda, and approximately 1,020 received an injection of placebo. Of the patients who received PEG-lambda, 25 (2.7%) were hospitalized, compared with 57 (5.6%) of the patients who received the placebo. The treatment therefore reduced the number of hospitalizations by half. Note that the reduction reached 58% when PEG-lambda was administered within three days of the onset of symptoms.
More effective in unvaccinated people
Even more strikingly, the researchers observed an 89% reduction in hospitalizations (compared to placebo), only in unvaccinated people treated within the first three days of the onset of symptoms. Furthermore, the drug was effective against all variants tested, including Omicron. Side effects were no greater than those reported by those who received the placebo.
Virologist Jeffrey Glenn, who led the work, believes that it is still relevant to find new treatments against Covid-19, for vaccinated and unvaccinated people. ” Given that vaccine-induced immunity wears off faster than expected, new variants of SARS-CoV-2 are constantly trying to outwit our immune systems, and people are reluctant to repeatedly get vaccinated by fear of real or imagined side effects (or vaccine fatigue), the need for effective Covid-19 therapies is paramount “, does he have declared.