An existing drug appears to reduce organ damage and mortality in people with covid-19. This has been shown by a small-scale study among thirty corona patients. The special thing about the medicine is that it does not shut down the entire immune system, as existing medicines do. The study was published at the end of last month in The Lancet Rheumatology.

"We are not there yet with this drug," emphasises research leader and ICU doctor Dr Alexander Vlaar. "A larger follow-up study (phase 3) should confirm this signal."

Thirty patients with a severe coronary infection took part in the study. The patients needed a lot of oxygen support. This is because the coronavirus triggers a strong inflammatory reaction that causes a lot of damage to the lungs. The perspective of these patients is not good. The risk of death is high and if they survive, a long rehabilitation period awaits them.

Phase 2 study

In the study, fifteen patients received standard care (the control group) and fifteen patients received an antibody that selectively quiets the immune system (the treatment group). The study shows that treatment with the new drug is safe. And more importantly: "The treatment group suffered less from blood clotting in the lungs and other serious consequences of a corona infection. Mortality was also lower," says Vlaar. "This does not prove that the drug is better than the existing care. The group is far too small to draw any responsible conclusions," he warns. That is why a phase 3 study is needed. Runaway immune system Many people get through a corona infection without too many problems. In this phase, drugs or antibodies that inhibit the division of the virus seem to be the best choice. In some cases, the disease worsens and a strong inflammatory reaction causes a lot of damage. These patients suffer from inflammation and clotting and often end up in the ICU. According to the researchers, antibodies or virus inhibitors are then probably no longer useful; the immune system must be calmed down.

In recent months, numerous immunosuppressive candidates have been reviewed, such as dexamethasone, prednisone and tocilizumab. The disadvantage is that these drugs either flatten the entire immune system or do not work at all. Moreover, many seriously ill patients who receive these drugs die. Doctors therefore want better medicines to become available.

Selective inhibition of the immune system

Vlaar: "We now know much more about the effects of the coronavirus on the immune system. An important player seems to be the so-called 'complement' system. A specific component of this is the C5a protein. In case of a serious corona infection, this substance disrupts the immune system and leads to the feared inflammations and clot formation. The idea is to neutralise only the C5a and leave the rest of the immune system intact." To achieve this effect, an antibody against C5a is needed. This already exists under the code name IFX-1 (Vilomebilab) and is used for other inflammatory diseases. It is known to selectively block C5a in adults, leaving the rest of the immune system unaffected. It was developed by the German biotech company InflaRx (GmbH) and has now been studied for the first time in a phase-2 study in critically ill corona patients. "The results are encouraging, but they need to be confirmed in a larger well-designed phase-3 study," says Vlaar. He designed the study together with other experts and InflaRx; this company initiated and sponsored the study. Phase 3 study Vlaar does not want to speculate on the future of the drug. Meanwhile, a phase-3 study initiated by InflaRx has been running at Amsterdam UMC since this week. "As hopeful as the phase-2 study is, we have to wait for the results of the phase-3 study," he said.

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